WorldWideScience

Sample records for anaerobic process effects

  1. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9.......6 addresses the mass balances and environmental aspects of anaerobic digestion....

  2. Dynamics of the anaerobic process: Effects of volatile fatty acids

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær

    2003-01-01

    A complex and fast dynamic response of the anaerobic biogas system was observed when the system was subjected to pulses of volatile fatty acids (VFAs). It was shown that a pulse of specific VFAs into a well-functioning continuous stirred tank reactor (CSTR) system operating on cow manure affected...... both CH4 yield, pH, and gas production and that a unique reaction pattern was seen for the higher VFAs as a result of these pulses. In this study, two thermophilic laboratory reactors were equipped with a novel VFA-sensor for monitoring specific VFAs online. Pulses of VFAs were shown to have a positive...... and the history of the reactor process. It should be pointed out that the observed dynamics of VFA responses were based on hourly measurements, meaning that the response duration was much lower than the hydraulic retention time, which exceeds several days in anaerobic CSTR systems....

  3. Effects of ion strength and ion pairing on (plant-wide) modelling of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Mbamba, Christian Kazadi; Solon, Kimberly;

    2014-01-01

    The objective of this study is to show the influence of ionic strength (as activity corrections) andion pairing on (plant-wide) modelling of anaerobic digestion processes in wastewater treatment plants(WWTPs). Using the Benchmark Simulation Model No. 2 (BSM2) as a case study, this paper presents...... the effects that an improved physico-chemical description will have on the predicted effluent quality (EQI) and operational cost (OCI) indices. The acid-base equilibria implemented in the Anaerobic Digestion Model No.1 (ADM1) are modified to account for non-ideal aqueous-phase chemistry. The model corrects...... processes. Results at high ionic strength demonstrate that corrections to account for non-ideal conditions lead to significant differences in predicted process performance. In addition, the paper describes: 1) how the anaerobic digester performance is affected; 2) the effect on pH and the anaerobic...

  4. The anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  5. Effects of nitrite on phosphate uptake in anaerobic-oxic process

    Institute of Scientific and Technical Information of China (English)

    LI Jie; XIONG Biyong; ZHANG Shude; YANG Hong; ZHANG Jie

    2007-01-01

    An anaerobic-oxic(A/O)biological phosphorus removal reactor was operated to study the effect of nitrite on phosphate uptake.The phosphorus uptake profile was determined under different operating conditions.The results indicated that in addition to oxygen and nitrate(DPBNa,nitrate denitrifying phosphorus removal),to some extent,nitrite could also serve as an electron acceptor to achieve nitrite denitrifying phosphorus removal(DPBNi).The quantity and rate of phosphorus uptake of DPBNi,however,were evidently lower than that of DPBNa.The experiment results revealed that nitrite would bring toxic action to phosphate accumulating organisms(PAOs)when NO2- -N≥93]7 mg/L.The nitrite existing in the anoxic reactor made no difference to the quantity and rate of denitrifying phosphorus removal,but it could reduce the consumption of nitrate.Moreover,the data showed that the aerobic phosphate uptake of DPBNi was lower than that of anaerobic phosphorus-released sludge in a traditional A/O process.However,there was not much difference between these two kinds of sludge in terms of the total phosphorus uptake quantity and the effluent quality.

  6. Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process

    OpenAIRE

    Flotats Ripoll, Xavier

    2013-01-01

    Mathematical modelling of anaerobic digestion process has been used to give new insights regarding dynamics of the long chain fatty acids (LCFA) inhibition. Previously published experimental data, including batch tests with clay mineral bentonite additions, were used for parameter identification. New kinetics were considered to describe the bio-physics of the inhibitory process, including: i) adsorption of LCFA over granular biomass and ii) specific LCFA substrate (saturated/unsaturated) a...

  7. Effects of multiple inhibitory components on anaerobic treatment processes in municipal solid waste incineration leachate.

    Science.gov (United States)

    Lei, Yuqing; Dang, Yan; Lan, Zhangheng; Sun, Dezhi

    2016-06-01

    This study served to investigate the comparative and combined effects of calcium, ammonia nitrogen, and aquatic humic substances (AHS) on specific methanogenic activity (SMA) in municipal solid waste leachate at mesophilic conditions. Using orthogonal experiments, anaerobic granular sludge was cultured with different concentrations combinations of the three added components for 13 days. The combination of 6000 mg/L calcium, 400 mg/L ammonia nitrogen, and 4000 mg/L AHS was the most inhibitory combination on the SMA of granular sludge, with a calculated 4.49 mL (standard temperature and atmospheric pressure) (STP) CH4/(gVSS·d) of SMA. The SMA with the addition of the inhibitory components was much lower than the control group's (1000 mg/L calcium, 200 mg/L ammonia nitrogen and 2000 mg/L AHS) with a calculated 12.97 mL (STP) CH4/(gVSS·d) of SMA. Calcium was the major inhibitor among the three components followed by AHS. High concentrations of calcium significantly inhibited the utilization of propionate and butyrate in the substrate and further affected the methanogenic process.

  8. Innovative two-stage anaerobic process for effective codigestion of cheese whey and cattle manure.

    Science.gov (United States)

    Bertin, Lorenzo; Grilli, Selene; Spagni, Alessandro; Fava, Fabio

    2013-01-01

    The valorisation of agroindustrial waste through anaerobic digestion represents a significant opportunity for refuse treatment and renewable energy production. This study aimed to improve the codigestion of cheese whey (CW) and cattle manure (CM) by an innovative two-stage process, based on concentric acidogenic and methanogenic phases, designed for enhancing performance and reducing footprint. The optimum CW to CM ratio was evaluated under batch conditions. Thereafter, codigestion was implemented under continuous-flow conditions comparing one- and two-stage processes. The results demonstrated that the addition of CM in codigestion with CW greatly improved the anaerobic process. The highest methane yield was obtained co-treating the two substrates at equal ratio by using the innovative two-stage process. The proposed system reached the maximum value of 258 mL(CH4) g(gv(-1), which was more than twice the value obtained by the one-stage process and 10% higher than the value obtained by the two-stage one.

  9. Modelling inhibitory effects of long chain fatty acids in the anaerobic digestion process.

    Science.gov (United States)

    Zonta, Z; Alves, M M; Flotats, X; Palatsi, J

    2013-03-01

    Mathematical modelling of anaerobic digestion process has been used to give new insights regarding dynamics of the long chain fatty acids (LCFA) inhibition. Previously published experimental data, including batch tests with clay mineral bentonite additions, were used for parameter identification. New kinetics were considered to describe the bio-physics of the inhibitory process, including: i) adsorption of LCFA over granular biomass and ii) specific LCFA substrate (saturated/unsaturated) and LCFA-degrading populations. Furthermore, iii) a new variable was introduced to describe the state of damage of the acetoclastic methanogens in order to account for the loss of cell-functionality (inhibition) induced by the adsorbed LCFAs. The proposed model modifications are state compatible and easy to be integrated into the International Water Association's Anaerobic Digestion Model N°1 (ADM1) framework. Practical identifiability of model parameters was assessed with a global sensitivity analysis, while calibration and model structure validation were performed on independent data sets. A reliable simulation of the LCFA-inhibition process can be achieved, if the model includes the description of the adsorptive nature of the LCFAs and the LCFA-damage over specific biomass. The importance of microbial population structure (saturated/unsaturated LCFA-degraders) and the high sensitivity of acetoclastic population to LCFA are evidenced, providing a plausible explanation of experimental based hypothesis.

  10. Electron beam/biological processing of anaerobic and aerobic sludge

    Science.gov (United States)

    Čuba, V.; Pospíšil, M.; Múčka, V.; Jeníček, P.; Dohányos, M.; Zábranská, J.

    2003-01-01

    Besides common chemical and biological methods, the radiation technology is a promising way of sludge treatment. The paper describes possibilities of combined accelerated electrons/biological processing of both anaerobic and aerobic sludge. Besides one-shot experiments, experimental reactors for the simulation of anaerobic processes have been used. Main effort has been aimed to decrease organic compounds concentration and overall volume of solids, to improve some physico-chemical parameters of sludge, to validate hygienisation effects of the ionising radiation, and in the case of anaerobic sludge, to increase the volume of the produced biogas. Positive effects of the electron beam processing have been observed on all previously named parameters.

  11. POLISHING THE EFFLUENT FROM AN ANAEROBIC BIOLOGICAL PERCHLORATE TREATMENT PROCESS

    Science.gov (United States)

    Anaerobic biological processes effectively reduce perchlorate to chloride. However, the effluent can be biologically unstable, high in particulates and high in disinfection by-product precursor compounds. Such an effluent would be unsuitable for transmission into a drinking water...

  12. Effect of continuous oleate addition on microbial communities involved in anaerobic digestion process

    DEFF Research Database (Denmark)

    Baserba, Manel Garrido; Angelidaki, Irini; Karakashev, Dimitar Borisov

    2012-01-01

    In the present study, the microbial diversity in anaerobic reactors, continuously exposed to oleate, added to a manure reactor influent, was investigated. Relative changes in archaeal community were less remarkable in comparison to changes in bacterial community indicating that dominant archaeal ...... a comprehensive picture on oleate degrading microbial communities in high organic strength wastewater. The findings might be utilized for development of strategies for biogas production from lipid-riched wastes....

  13. Effects of volatile fatty acids on a thermophilic anaerobic hydrogen fermentation process degrading peptone.

    Science.gov (United States)

    Cheng, S S; Chang, S M; Chen, S T

    2002-01-01

    Hydrogen fermentation using glucose as a single substrate caused abrupt pH drops and the gradual losses of hydrogen producers, which in turn led to system failure. In this study the use of a proteinaceous substrate, peptone, avoided the abrupt pH drops in the reactive system and allowed for further exploration of volatile fatty acids (VFAs) and pH effects on the hydrogen fermentation process. Our results showed that: (1) during the hydrogen fermentation tests, the abrupt pH drops were avoided thus system stability increased due to the production of ammonia from the peptone fermented, (2) pH control was not necessary and the addition of acetate to the process had little effect on the hydrogen fermentation process, (3) at the extreme pHs the addition of acetate either lengthened the lag phase (pH hydrogen production rate (pH > or = 8), and both situations were not desired, and (4) high VFA content in the system sped up the consumption of hydrogen gas. Results of this study suggested that the hydrogen fermentation using the protein-containing substances as substrate was beneficial in maintaining the system pH. As long as the pH was maintained around 6-8, system inhibition due to VFAs accumulation was minimized. Thus, the optimal operation of a hydrogen fermentation process would be achievable via the control of substrate composition at a certain carbohydrate-to-protein ratio.

  14. Robust regulation of anaerobic digestion processes.

    Science.gov (United States)

    Mailleret, L; Bernard, O; Steyer, J P

    2003-01-01

    This paper deals with the problem of controlling anaerobic digestion processes. A two-step (i.e. acidogenesis-methanization) mass balance model is considered for a 1 m3 fixed bed digester treating industrial wine distillery wastewater. The control law aims at regulating the organic pollution level while avoiding washout of biomass. To this end, a simple output feedback controller is considered which regulates a variable strongly related to the Chemical Oxygen Demand (COD). Numerical simulations assuming noisy measurements first illustrate the robustness of this control procedure. Then, the regulating procedure is implemented on the considered anaerobic digestion process in order to validate and demonstrate its efficiency in real life experiments.

  15. Kinetics and modeling of anaerobic digestion process

    DEFF Research Database (Denmark)

    2003-01-01

    Anaerobic digestion modeling started in the early 1970s when the need for design and efficient operation of anaerobic systems became evident. At that time not only was the knowledge about the complex process of anaerobic digestion inadequate but also there were computational limitations. Thus......, the first models were very simple and consisted of a limited number of equations. During the past thirty years much research has been conducted on the peculiarities of the process and on the factors that influence it on the one hand while an enormous progress took place in computer science on the other....... The combination of both parameters resulted in the development of more and more concise and complex models. In this chapter the most important models found in the literature are described starting from the simplest and oldest to the more recent and complex ones....

  16. Oxygen Effects in Anaerobic Digestion - II

    Directory of Open Access Journals (Sweden)

    Deshai Botheju

    2010-04-01

    Full Text Available Standard models describing bio-gasification using anaerobic digestion do not include necessary processes to describe digester dynamics under the conditions of oxygen presence. Limited oxygenation in anaerobic digestion can sometimes be beneficial. The oxygen effects included anaerobic digestion model, ADM 1-Ox, was simulated against experimental data obtained from laboratory scale anaerobic digesters operated under different oxygenation conditions. ADM 1-Ox predictions are generally in good agreement with the trends of the experimental data. ADM 1-Ox simulations suggest the existence of an optimum oxygenation level corresponding to a peak methane yield. The positive impact of oxygenation on methane yield is more pronounced at conditions characterized by low hydrolysis rate coefficients (slowly degradable feed and low biomass concentrations. The optimum oxygenation point moves towards zero when the hydrolysis rate coefficient and the biomass concentration increase. Accordingly, the impact of oxygenation on methane yield can either be positive or negative depending on the digestion system characteristics. The developed ADM 1-Ox model can therefore be a valuable tool for recognizing suitable operating conditions for achieving the maximum benefits from partial aeration in anaerobic digestion.

  17. Anammox for nitrogen removal from anaerobically pre-treated municipal wastewater: Effect of COD/N ratios on process performance and bacterial community structure.

    Science.gov (United States)

    Leal, Cíntia Dutra; Pereira, Alyne Duarte; Nunes, Fernando Terra; Ferreira, Luísa Ornelas; Coelho, Aline Carolina Cirilo; Bicalho, Sarah Kinaip; Mac Conell, Erika F Abreu; Ribeiro, Thiago Bressani; de Lemos Chernicharo, Carlos Augusto; de Araújo, Juliana Calábria

    2016-07-01

    Long-term effects of COD/N ratios on the nitrogen removal performance and bacterial community of an anammox reactor were evaluated by adding a synthetic medium (with glucose) and real anaerobic effluent to a SBR. At a COD/N ratio of 2.8 (COD, 390mg·L(-1)) ammonium removal efficiency was 66%, while nitrite removal remained high (99%). However, at a COD/N ratio of 5.0 (COD, 300mg·L(-1)), ammonium and nitrite removal efficiencies were high (84% and 99%, respectively). High COD, nitrite, and ammonium removal efficiencies (80%, 90% and 95%, respectively) were obtained on adding anaerobically pre-treated municipal wastewater (with nitrite) to the reactor. DGGE revealed that the addition of anaerobic effluent changed the bacterial community structure and selected for DNA sequences related to Brocadia sinica and Chloroflexi. Adding glucose and anaerobic effluent increased denitrifiers concentration threefold. Thus, the possibility of using the anammox process to remove nitrogen from anaerobically pre-treated municipal wastewater was demonstrated.

  18. Hybrid modelling of anaerobic wastewater treatment processes.

    Science.gov (United States)

    Karama, A; Bernard, O; Genovesi, A; Dochain, D; Benhammou, A; Steyer, J P

    2001-01-01

    This paper presents a hybrid approach for the modelling of an anaerobic digestion process. The hybrid model combines a feed-forward network, describing the bacterial kinetics, and the a priori knowledge based on the mass balances of the process components. We have considered an architecture which incorporates the neural network as a static model of unmeasured process parameters (kinetic growth rate) and an integrator for the dynamic representation of the process using a set of dynamic differential equations. The paper contains a description of the neural network component training procedure. The performance of this approach is illustrated with experimental data.

  19. Anaerobic digestion of organic by-products from meat-processing industry. The effect of pre-treatments and co-digestion

    Energy Technology Data Exchange (ETDEWEB)

    Luste, S.

    2011-07-01

    suitable for anaerobic co-digestion. The co-digestion of the ABPs with sewage sludge and cattle slurry resulted improved methane production and reusability of the digestate. These enhancements were further improved by the pre-treatments studied. The most suitable (ultrasound and bacterial product addition) and synergistically beneficial (pre-hygienisation) pretreatments were found to enhance the complex degradation of materials. Pre-treatments effects on the whole process and on the end-products were depended on the hydrolysis values, but especially on the content of the materials and qualities of the solubilised compounds. Economical feasibility of ultrasound and hygienisation pre-treatments is attainable. Materials and process methods studied in this thesis offer required new information and aspects about the case- and material-specific factors of process requirements, process optimisation according to the requirements in practice, degradability of the ABP materials, hygienic matters and mechanisms involved in pre-treatments and co-digestion of ABPs. The information produced could be directly utilised in the practical implementations of the anaerobic digestion of studied or corresponding materials and feed mixtures. (orig.)

  20. Modelling sodium inhibition on the anaerobic digestion process.

    Science.gov (United States)

    Hierholtzer, A; Akunna, J C

    2012-01-01

    Sodium is a known process inhibitor in anaerobic systems and impacts on methanogens through an increase of osmotic pressure or complete dehydration of microorganisms. In this study, a combination of experimental and modelling approaches has been employed to determine and simulate sodium inhibition on the anaerobic digestion process. The ADM1, which has been successfully used in modelling anaerobic processes, has been modified to include an extra inhibition function that considers the effect of sodium on acetoclastic methanogens and the impact on biogas production and composition. A non-competitive inhibition function was added to the rate of acetate uptake for the model to take into account sodium toxicity. Experimental studies consisted of both batch and reactor tests to obtain parameters for model calibration and validation. The calibrated model was used to predict the effect of ammonia nitrogen on sodium toxicity. It was found that relatively low sodium levels can bring about significant levels of process inhibition in the presence of high levels of ammonia. On the other hand, where the concentration of ammonia is relatively low, the tolerance threshold for sodium ions increases. Hence, care must be taken in the use of sodium hydroxide for pH adjustment during anaerobic digestion of protein-rich substrates.

  1. Anaerobic Digestion. Student Manual. Biological Treatment Process Control.

    Science.gov (United States)

    Carnegie, John W., Ed.

    This student manual contains the textual material for a four-lesson unit on anaerobic digestion control. Areas addressed include: (1) anaerobic sludge digestion (considering the nature of raw sludge, purposes of anaerobic digestion, the results of digestion, types of equipment, and other topics); (2) digester process control (considering feeding…

  2. Effect of the Organic Loading Rate Increase and the Presence of Zeolite on Microbial Community Composition and Process Stability During Anaerobic Digestion of Chicken Wastes.

    Science.gov (United States)

    Ziganshina, Elvira E; Belostotskiy, Dmitry E; Ilinskaya, Olga N; Boulygina, Eugenia A; Grigoryeva, Tatiana V; Ziganshin, Ayrat M

    2015-11-01

    This study investigates the effect of the organic loading rate (OLR) increase from 1.0 to 3.5 g VS L(-1) day(-1) at constant hydraulic retention time (HRT) of 35 days on anaerobic reactors' performance and microbial diversity during mesophilic anaerobic digestion of ammonium-rich chicken wastes in the absence/presence of zeolite. The effects of anaerobic process parameters on microbial community structure and dynamics were evaluated using a 16S ribosomal RNA gene-based pyrosequencing approach. Maximum 12 % of the total ammonia nitrogen (TAN) was efficiently removed by zeolite in the fixed zeolite reactor (day 87). In addition, volatile fatty acids (VFA) in the fixed zeolite reactor accumulated in lower concentrations at high OLR of 3.2-3.5 g VS L(-1) day(-1). Microbial communities in the fixed zeolite reactor and reactor without zeolite were dominated by various members of Bacteroidales and Methanobacterium sp. at moderate TAN and VFA levels. The increase of the OLR accompanied by TAN and VFA accumulation and increase in pH led to the predominance of representatives of the family Erysipelotrichaceae and genera Clostridium and Methanosarcina. Methanosarcina sp. reached relative abundances of 94 and 57 % in the fixed zeolite reactor and reactor without zeolite at the end of the experimental period, respectively. In addition, the diminution of Synergistaceae and Crenarchaeota and increase in the abundance of Acholeplasmataceae in parallel with the increase of TAN, VFA, and pH values were observed.

  3. Linearizing control of continuous anaerobic fermentation processes

    Energy Technology Data Exchange (ETDEWEB)

    Babary, J.P. [Centre National d`Etudes Spatiales (CNES), 31 - Toulouse (France). Laboratoire d`Analyse et d`Architecture des Systemes; Simeonov, I. [Institute of Microbiology, Bulgarian Academy of Sciences (Bulgaria); Ljubenova, V. [Institute of Control and System Research, BAS (Country unknown/Code not available); Dochain, D. [Universite Catholique de Louvain (UCL), Louvain-la-Neuve (Belgium)

    1997-09-01

    Biotechnological processes (BTP) involve living organisms. In the anaerobic fermentation (biogas production process) the organic matter is mineralized by microorganisms into biogas (methane and carbon dioxide) in the absence of oxygen. The biogas is an additional energy source. Generally this process is carried out as a continuous BTP. It has been widely used in life process and has been confirmed as a promising method of solving some energy and ecological problems in the agriculture and industry. Because of the very restrictive on-line information the control of this process in continuous mode is often reduced to control of the biogas production rate or the concentration of the polluting organic matter (de-pollution control) at a desired value in the presence of some perturbations. Investigations show that classical linear controllers have good performances only in the linear zone of the strongly non-linear input-output characteristics. More sophisticated robust and with variable structure (VSC) controllers are studied. Due to the strongly non-linear dynamics of the process the performances of the closed loop system may be degrading in this case. The aim of this paper is to investigate different linearizing algorithms for control of a continuous non-linear methane fermentation process using the dilution rate as a control action and taking into account some practical implementation aspects. (authors) 8 refs.

  4. Applications of the anaerobic digestion process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ellegaard, L.; Ahring, Birgitte Kiær

    2003-01-01

    and incineration of organic waste has become less desirable, and legislation, both in Europe and elsewhere, tends to favor biological treatment as a way of recycling minerals and nutrients of organic wastes from society back to the food production and supply chain. Removing the relatively wet organic waste from......At the start of the new millennium waste management has become a political priority in many countries. One of the main problems today is to cope with an increasing amount of primary waste in an environmentally acceptable way. Biowastes, i.e., municipal, agricultural or industrial organic waste...... and resource/energy recovery have been developed. Treatment of biowastes by anaerobic digestion processes is in many cases the optimal way to convert organic waste into useful products such as energy (in the form of biogas) and a fertilizer product. Other waste management options, such as land filling...

  5. EFFECT OF MUSIC ON ANAEROBIC EXERCISE PERFORMANCE

    OpenAIRE

    Atan, T.

    2013-01-01

    For years, mostly the effects of music on cardiorespiratory exercise performance have been studied, but a few studies have examined the effect of music on anaerobic exercise. The purpose of this study was to assess the effect of listening to music and its rhythm on anaerobic exercise: on power output, heart rate and the concentration of blood lactate. 28 male subjects were required to visit the laboratory on 6 occasions, each separated by 48 hours. Firstly, each subject performed the Running-...

  6. Effects of Benzalkonium Chloride, Proxel LV, P3 Hypochloran, Triton X-100 and DOWFAX 63N10 on anaerobic digestion processes.

    Science.gov (United States)

    Flores, German Antonio Enriquez; Fotidis, Ioannis A; Karakashev, Dimitar Borisov; Kjellberg, Kasper; Angelidaki, Irini

    2015-10-01

    In this study, the individual and synergistic toxicity of the following xenobiotics: Benzalkonium Chloride (BKC), Proxel LV (PRX), P3 Hypochloran (HPC), Triton X-100 (TRX), and DOWFAX 63N10 (DWF), on anaerobic digestion (AD) process, was assessed. The experiments were performed in batch and continuous (up-flow anaerobic sludge blanket, UASB) reactors with biochemical-industrial wastewater, as substrate. In batch experiments, half-maximal inhibitory concentrations (IC50) for the tested xenobiotics were found to be 13.1, 1003, 311.5 and 24.3 mg L(-1) for BKC, PRX, DWF and TRX, respectively while HPC did not affect the AD process. Furthermore, the xenobiotics mixture tested did not present any synergistic inhibitory effect on the AD process. In continuous experiments, BKC and xenobiotics' mixture induced even stronger (more than 85%) of inhibition, expressed as IC50, compared to the levels observed from the batch reactors. Oppositely, TRX showed no inhibition in continuous mode, while inhibition was detected at batch mode.

  7. Inhibition of the anaerobic digestion process by linear alkylbenzene sulfonates

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Ahring, Birgitte Kiær

    2002-01-01

    Linear Alkylbenzene Sulfonates (LAS) are the most widely used synthetic anionic surfactants. They are anthropogenic, toxic compounds and are found in the primary sludge generated in municipal wastewater treatment plants. Primary sludge is usually stabilized anaerobically and therefore...... of the anaerobic digestion process should be seriously taken into consideration when wastewater from a surfactant producing industry is to be treated biologically or enter a municipal wastewater treatment plant that employs anaerobic technology. The upper allowable biomass specific LAS concentration should be 14...

  8. Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Suschka Jan

    2014-07-01

    Full Text Available Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

  9. The Pasteur effect in facultative anaerobic metazoa.

    Science.gov (United States)

    Schmidt, H; Kamp, G

    1996-05-15

    The existence and the regulatory mechanisms of the Pasteur effect in facultative anaerobic metazoa are discussed. There are three reasons for the controversy surrounding this phenomenon. 1) The different definitions of the Pasteur effect, 2) the antagonistic effect of metabolic depression and its species specific response to hypoxia, as well as 3) the laboratory-specific differences in the experimental procedures for analyzing the Pasteur effect and its regulation. This review aims to clarify the confusion about the existence of the Pasteur effect in facultative anaerobic metazoa and to offer possible molecular mechanisms.

  10. POLISHING THE EFFLUENT FROM AN ANAEROBIC BIOLOGICAL PERCHLORATE TREATMENT PROCESS - SLIDES

    Science.gov (United States)

    Anaerobic biological processes effectively reduce perchlorate to chloride. However, the effluent can be biologically unstable, high in particulates and high in disinfection by-product precursor compounds. Such an effluent would be unsuitable for transmission into a drinking water...

  11. Effects of Benzalkonium Chloride, Proxel LV, P3 Hypochloran, Triton X-100 and DOWFAX 63N10 on anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores, German Antonio Enriquez; Fotidis, Ioannis; Karakashev, Dimitar Borisov

    2015-01-01

    In this study, the individual and synergistic toxicity of the following xenobiotics: Benzalkonium Chloride (BKC), Proxel LV (PRX), P3 Hypochloran (HPC), Triton X-100 (TRX), and DOWFAX 63N10 (DWF), on anaerobic digestion (AD) process, was assessed. The experiments were performed in batch and conti...

  12. The effect of tannic compounds on anaerobic wastewater treatment.

    NARCIS (Netherlands)

    Field, J.A.

    1989-01-01

    Anaerobic wastewater treatment is an alternative to the conventional aerobic treatment processes for the removal of easily biodegradable organic matter in medium to high strength industrial wastestreams. Anaerobic treatment has several advantages, however one important disadvantage is the high sensi

  13. Effect of different pH-values on process parameters in two-phase anaerobic digestion of high-solid substrates.

    Science.gov (United States)

    Lindner, Jonas; Zielonka, Simon; Oechsner, Hans; Lemmer, Andreas

    2015-01-01

    In many publications, primary fermentation is described as a limiting step in the anaerobic digestion of fibre-rich biomass [Eastman JA, Ferguson JF. Solubilization of particulacte carbon during the anaerobic digeston. J WPCF. 1981;53:352-366; Noike T, Endo G, Chang J, Yaguchi J, Matsumoto J. Characteristics of carbohydrate degradation and the rate-limiting step in anaerobic digestion. Biotechnol Bioeng. 1985;27:1482-1489; Arntz HJ, Stoppok E, Buchholz K. Anaerobic hydroysis of beet pulp-discontiniuous experiments. Biotechnol Lett. 1985;7:113-118]. The microorganisms of the primary fermentation process differ widely from the methanogenic microorganisms [Pohland FG, Ghosh S. Developments in anaerobic stabilization of organic wastes-the two-phase concept. Environ Lett. 1971;1:255-266]. To optimize the biogas process, a separation in two phases is suggested by many authors [Fox P, Pohland GK. Anaerobic treatment applications and fundamentals: substrate specificity during phase separation. Water Environ Res. 1994;66:716-724; Cohen A, Zoetemeyer RJ, van Deursen A, van Andel JG. Anaerobic digestion of glucose with separated acid production and methane formation. Water Res. 1979;13:571-580]. To carry out the examination, a two-phase laboratory-scale biogas plant was established, with a physical phase separation. In previous studies, the regulation of the pH-value during the acid formation was usually carried out by the addition of sodium hydroxide [Cohen A, Zoetemeyer RJ, van Deursen A, van Andel JG. Anaerobic digestion of glucose with separated acid production and methane formation. Water Res. 1979;13:571-580; Ueno Y, Tatara M, Fukui H, Makiuchi T, Goto M, Sode K. Production of hydrogen and methane from organic solid wastes by phase separation of anaerobic process. Bioresour Technol. 2007;98:1861-1865; Zoetemeyer RJ, van den Heuvel JC, Cohen A. pH influence on acidogenic dissimilation of glucose in an anaerobic digestor. Water Res. 1982;16:303-311]. A new technology

  14. Characteristics, Process Parameters, and Inner Components of Anaerobic Bioreactors

    Science.gov (United States)

    Abdelgadir, Awad; Chen, Xiaoguang; Liu, Jianshe; Xie, Xuehui; Zhang, Jian; Zhang, Kai; Wang, Heng; Liu, Na

    2014-01-01

    The anaerobic bioreactor applies the principles of biotechnology and microbiology, and nowadays it has been used widely in the wastewater treatment plants due to their high efficiency, low energy use, and green energy generation. Advantages and disadvantages of anaerobic process were shown, and three main characteristics of anaerobic bioreactor (AB), namely, inhomogeneous system, time instability, and space instability were also discussed in this work. For high efficiency of wastewater treatment, the process parameters of anaerobic digestion, such as temperature, pH, Hydraulic retention time (HRT), Organic Loading Rate (OLR), and sludge retention time (SRT) were introduced to take into account the optimum conditions for living, growth, and multiplication of bacteria. The inner components, which can improve SRT, and even enhance mass transfer, were also explained and have been divided into transverse inner components, longitudinal inner components, and biofilm-packing material. At last, the newly developed special inner components were discussed and found more efficient and productive. PMID:24672798

  15. A bio-electrochemical system for removing inhibitors of anaerobic digestion processes from anaerobic reactors

    DEFF Research Database (Denmark)

    2014-01-01

    Inhibition of anaerobic digestion process by high level of ammonia (NH4 +/I\\IH3) is the most serious problem existing in biogas plants. No viable/applicable method to overcome this problem has been found up to now. This invention proposes an innovative submersible bio-electrochemical membrane...... reactor to recover ammonia from anaerobic digestion reactor, and thereby alleviate or counteract ammonia inhibition and enhance the conversion of ammonia-rich wastes to biogas. The invention may further reduce overall cost, giving synergistic advantages for both ammonia recycling and biogas plants...

  16. Cost-effectiveness analysis of TOC removal from slaughterhouse wastewater using combined anaerobic-aerobic and UV/H2O2 processes.

    Science.gov (United States)

    Bustillo-Lecompte, Ciro Fernando; Mehrvar, Mehrab; Quiñones-Bolaños, Edgar

    2014-02-15

    The objective of this study is to evaluate the operating costs of treating slaughterhouse wastewater (SWW) using combined biological and advanced oxidation processes (AOPs). This study compares the performance and the treatment capability of an anaerobic baffled reactor (ABR), an aerated completely mixed activated sludge reactor (AS), and a UV/H2O2 process, as well as their combination for the removal of the total organic carbon (TOC). Overall efficiencies are found to be up to 75.22, 89.47, 94.53, 96.10, 96.36, and 99.98% for the UV/H2O2, ABR, AS, combined AS-ABR, combined ABR-AS, and combined ABR-AS-UV/H2O2 processes, respectively. Due to the consumption of electrical energy and reagents, operating costs are calculated at optimal conditions of each process. A cost-effectiveness analysis (CEA) is performed at optimal conditions for the SWW treatment by optimizing the total electricity cost, H2O2 consumption, and hydraulic retention time (HRT). The combined ABR-AS-UV/H2O2 processes have an optimal TOC removal of 92.46% at an HRT of 41 h, a cost of $1.25/kg of TOC removed, and $11.60/m(3) of treated SWW. This process reaches a maximum TOC removal of 99% in 76.5 h with an estimated cost of $2.19/kg TOC removal and $21.65/m(3) treated SWW, equivalent to $6.79/m(3) day.

  17. Effect of aerobic pre-treatment on hydrogen and methane production in a two-stage anaerobic digestion process using food waste with different compositions.

    Science.gov (United States)

    Rafieenia, Razieh; Girotto, Francesca; Peng, Wei; Cossu, Raffaello; Pivato, Alberto; Raga, Roberto; Lavagnolo, Maria Cristina

    2017-01-01

    Aerobic pre-treatment was applied prior to two-stage anaerobic digestion process. Three different food wastes samples, namely carbohydrate rich, protein rich and lipid rich, were prepared as substrates. Effect of aerobic pre-treatment on hydrogen and methane production was studied. Pre-aeration of substrates showed no positive impact on hydrogen production in the first stage. All three categories of pre-aerated food wastes produced less hydrogen compared to samples without pre-aeration. In the second stage, methane production increased for aerated protein rich and carbohydrate rich samples. In addition, the lag phase for carbohydrate rich substrate was shorter for aerated samples. Aerated protein rich substrate yielded the best results among substrates for methane production, with a cumulative production of approximately 351ml/gVS. With regard to non-aerated substrates, lipid rich was the best substrate for CH4 production (263ml/gVS). Pre-aerated P substrate was the best in terms of total energy generation which amounted to 9.64kJ/gVS. This study revealed aerobic pre-treatment to be a promising option for use in achieving enhanced substrate conversion efficiencies and CH4 production in a two-stage AD process, particularly when the substrate contains high amounts of proteins.

  18. Mathematical modelling of anaerobic digestion processes: applications and future needs

    DEFF Research Database (Denmark)

    Batstone, Damien J.; Puyol, Daniel; Flores Alsina, Xavier

    2015-01-01

    Anaerobic process modelling is a mature and well-established field, largely guided by a mechanistic model structure that is defined by our understanding of underlying processes. This led to publication of the IWA ADM1, and strong supporting, analytical, and extension research in the 15 years sinc...

  19. Biochemical reaction engineering and process development in anaerobic wastewater treatment.

    Science.gov (United States)

    Aivasidis, Alexander; Diamantis, Vasileios

    2005-01-01

    Developments in production technology have frequently resulted in the concentrated local accumulation of highly organic-laden wastewaters. Anaerobic wastewater treatment, in industrial applications, constitutes an advanced method of synthesis by which inexpensive substrates are converted into valuable disproportionate products. A critical discussion of certain fundamental principles of biochemical reaction engineering relevant to the anaerobic mode of operation is made here, with special emphasis on the roles of thermodynamics, kinetics, mass and heat transfer, reactor design, biomass retention and recycling. The applications of the anaerobic processes are discussed, introducing the principles of an upflow anaerobic sludge bed reactor and a fixed-bed loop reactor. The merits of staging reactor systems are presented using selected examples based on two decades of research in the field of anaerobic fermentation and wastewater treatment at the Forschungszentrum Julich (Julich Research Center, Germany). Wastewater treatment is an industrial process associated with one of the largest levels of mass throughput known, and for this reason it provides a major impetus to further developments in bioprocess technology in general.

  20. Thermophilic anaerobic waste water treatment, temperature aspects and process stability.

    NARCIS (Netherlands)

    Lier, van J.B.

    1995-01-01

    The main objective of this thesis was to assess the thermostability of thermophilic anaerobic wastewater treatment processes and the possibility to optimize the performance of thermophilic high-rate systems.Experiments were conducted to study the suitability of two types of seed material to start a

  1. The effect of anaerobic fermentation processing of cattle waste for biogas as a renewable energy resources on the number of contaminant microorganism

    Science.gov (United States)

    Kurnani, Tb. Benito A.; Hidayati, Yuli Astuti; Marlina, Eulis Tanti; Harlia, Ellin

    2016-02-01

    Beef cattle waste has a positive potential that can be exploited, as well as a negative potential that must be controlled so as not to pollute the environment. Beef cattle waste can be processed into an alternative energy, namely biogas. Anaerobic treatment of livestock waste to produce gas can be a solution in providing optional energy, while the resulted sludge as the fermentation residue can be used as organic fertilizer for crops. However, this sludge may containt patogenic microorganism that will damage human and environmet healt. Therefor, this study was aimed to know the potency of beef cattle waste to produce biogas and the decrease of the microorganism's number by using fixed dome digester. Beef cattle waste was processed into biogas using fixed dome digester with a capacity of 12 m3. Biogas composition was measured using Gas Cromatografi, will microorganism species was identified using Total plate Count Methode. The result of this study shows that the produced biogas contains of 75.77% Mol (CH4), 13.28% Mol (N), and 6.96% Mol (CO2). Furthermor, this study show that the anaerobic fermrntation process is capable of reducing microorganisms that could potentially pollute the environment. The number of Escherichia coli and Samonella sp. were <30 MPN/ml respectively save for environment. This process can reduce 84.70% the amount of molds. The only molds still existed after fermentation was A.fumigatus. The number of protozoa can be reduced in order of 94.73%. Protozoa that can be identified in cattle waste before, and after anaerobic fermentation was merely Eimeria sp.. The process also reduced the yeast of 86.11%. The remaining yeast after fermentation was Candida sp. Finally, about 93.7% of endoparasites was reduced by this process. In this case, every trematode and cestoda were 100% reduced, while the nematode only 75%. Reducing some microorganisms that have the potential to pollute the environment signifies sludge anaerobic fermentation residue is safe to

  2. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    Science.gov (United States)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

  3. Fault detection filter design for an anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Aubrun, C.; Garnier, O. [Univ. Henri Poincare - Nancy 1, Vandoeuvre (France); Harmand, J.; Steyer, J.P. [LBE-INRA, Narbonne (France)

    2000-05-01

    In this paper, a Fault Detection and Isolation observer based method has been applied to biological wastewater treatment process. The method is designed with a dynamic model and the observer is determined using the eigenstructure assignment approach. The efficiency of the method is demonstrated for both detection and isolation of an actuator and a sensor failure using experimental data from a pilot scale anaerobic digestion process for the treatment of an industrial wine distillery vinasses. (orig.)

  4. A robust and cost-effective integrated process for nitrogen and bio-refractory organics removal from landfill leachate via short-cut nitrification, anaerobic ammonium oxidation in tandem with electrochemical oxidation.

    Science.gov (United States)

    Wu, Li-Na; Liang, Da-Wei; Xu, Ying-Ying; Liu, Ting; Peng, Yong-Zhen; Zhang, Jie

    2016-07-01

    A cost-effective process, consisting of a denitrifying upflow anaerobic sludge blanket (UASB), an oxygen-limited anoxic/aerobic (A/O) process for short-cut nitrification, and an anaerobic reactor (ANR) for anaerobic ammonia oxidation (anammox), followed by an electrochemical oxidation process with a Ti-based SnO2-Sb2O5 anode, was developed to remove organics and nitrogen in a sewage diluted leachate. The final chemical oxygen demand (COD), ammonia nitrogen (NH4(+)-N) and total nitrogen (TN) of 70, 11.3 and 39 (all in mg/L), respectively, were obtained. TN removal in UASB, A/O and ANR were 24.6%, 49.6% and 16.1%, respectively. According to the water quality and molecular biology analysis, a high degree of anammox besides short-cut nitrification and denitrification occurred in A/O. Counting for 16.1% of TN removal in ANR, at least 43.2-49% of TN was removed via anammox. The anammox bacteria in A/O and ANR, were in respective titers of (2.5-5.9)×10(9) and 2.01×10(10)copy numbers/(gSS).

  5. Effect of temperature and pH on the kinetics of methane production, organic nitrogen and phosphorus removal in the batch anaerobic digestion process of cattle manure

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, E. [Consultores Ambientales (CONAM), Havanna (Cuba); Borja, R. [Instituto de la Grasa (C.S.I.C.)., Sevilla (Spain); Weiland, P. [Institute of Technology, Federal Research Center of Agriculture (FAL), Braunschweig (Germany); Travieso, L. [Departamento de Estudios sobre Contaminacion Ambiental (DECA-CNIC), Centro Nacional de Investigaciones Cientificas (CNIC), La Habana (Cuba); Martin, A. [Departamento de Ingenieria Quimica, Facultad de Ciencias, Cordoba (Spain)

    2000-03-01

    A study of the effect of temperature and pH on the kinetics of methane production and organic nitrogen and phosphorus degradation in the anaerobic digestion process of cattle manure was carried out. Two laboratory-scale batch completely mixed reactors, operating at 35 C (mesophilic temperature), and other two, operating at 60 C (thermophilic temperature) were used. For each temperature selected, the influent pH values were 7.6 (initial pH of the waste used) and 7.0. The apparent kinetic constants of the biomethanization process increased 2.3 times when the initial pH of the influent was increased from 7.0 to 7.6 at mesophilic temperature. The values found at thermophilic temperature were similar. The kinetic constants of methane production decreased 2.6 and 7.2 times when the operating temperature increased from 35 C to 60 C for the experiments carried out at initial pH of 7.0 and 7.6, respectively. The methane yield coefficient (l CH{sub 4} STP/g VS removed) also decreased when the temperature increased from 35 C to 60 C for the two initial pH values studied. This behaviour agreed with the major inhibition level observed at thermophilic temperature as a result of the higher organic nitrogen removal and ammonia nitrogen production observed at 60 C. Specifically, the specific rate constants for organic nitrogen removal and ammonia nitrogen production increased 3.6 and 12 times when the temperature was increased from 35 C to 60 C for the experiments carried out at initial pH values of 7.0 and 7.6, respectively. In the same way, the values of the kinetic constant for phosphorus removal were 44% and 80% higher than those obtained at 35 C for the two initial pH values above-mentioned, respectively. Finally, the experimental values of organic nitrogen and phosphorus concentrations were reproduced with deviations equal to or less than 10% and 15% in every case, respectively. (orig.)

  6. EFFECTS OF ECCENTRIC EXERCISE ON ANAEROBIC POWER, STARTING SPEED AND ANAEROBIC ENDURANCE

    OpenAIRE

    Maciejczyk, Marcin; Szymura, Jadwiga; Wiecek, Magdalena; Szygula, Zbigniew; Kepinska, Magdalena; Ochalek, Katarzyna; Pokrywka, Andrzej

    2015-01-01

    The aim of this study was to evaluate the effects of eccentric exercise on anaerobic power, starting speed and anaerobic endurance. The participants performed the maximum cycling sprint test (MCST) prior to eccentric exercise (ECC), 10 minutes after, as well as one hour, 24 hours, 48 hours, and one week after ECC. The peak and mean power, time to attain peak power, time of maintaining peak power and power decrease were measured in the MCST. Before and after ECC, the myoglobin concentration...

  7. Improved ADM1 model for anaerobic digestion process considering physico-chemical reactions.

    Science.gov (United States)

    Zhang, Yang; Piccard, Sarah; Zhou, Wen

    2015-11-01

    The "Anaerobic Digestion Model No. 1" (ADM1) was modified in the study by improving the bio-chemical framework and integrating a more detailed physico-chemical framework. Inorganic carbon and nitrogen balance terms were introduced to resolve the discrepancies in the original bio-chemical framework between the carbon and nitrogen contents in the degraders and substrates. More inorganic components and solids precipitation processes were included in the physico-chemical framework of ADM1. The modified ADM1 was validated with the experimental data and used to investigate the effects of calcium ions, magnesium ions, inorganic phosphorus and inorganic nitrogen on anaerobic digestion in batch reactor. It was found that the entire anaerobic digestion process might exist an optimal initial concentration of inorganic nitrogen for methane gas production in the presence of calcium ions, magnesium ions and inorganic phosphorus.

  8. Effect of anaerobic bovine colostrum fermentation on bacteria growth inhibition

    Directory of Open Access Journals (Sweden)

    Mara Helena Saalfeld

    Full Text Available ABSTRACT: Efficient handling programs that provide high quality colostrum in adequate amounts to dairy farm calves are needed to assure their health and survival. Replacers (or milk substitutes often become necessary when colostrum presents inadequate quality, or in order to break the cycle of infectious disease transmission. In this study we aimed to assess the effect of anaerobic fermentation processing (colostrum silage on bacterial that represent interest to animal health. Colostrum samples were inoculated with cultures of Brucella abortus , Escherichia coli , Leptospira interrogans serovar Copenhageni , Mycobacterium bovis , Salmonella Enteritidis , Salmonella Typhimurium , Staphylococcus aureus , and Bacillus cereus and then subjected to anaerobic fermentation. On the first day, and every seven days until 30th days after fermentation, the samples were cultured and colony forming units counted. At seven days of fermentation, B. abortus , L. interrogans , and M. bovis were not detected. At 14th days of fermentation, E. coli , S. aureus , S. Enteritidis and S. Typhimurium were no longer detected. However, we were able to detect both lactic acid bacteria and B. cereus until 30th days of fermentation. From this study we suggested that anaerobic fermentation processing can inhibit important bacteria that cause economical losses for the cattle industry. The observations suggested that colostrum silage is a promising form to conserve bovine colostrum.

  9. Effect of ultrasonication on anaerobic degradability of solid waste digestate.

    Science.gov (United States)

    Boni, M R; D'Amato, E; Polettini, A; Pomi, R; Rossi, A

    2016-02-01

    This paper evaluates the effect of ultrasonication on anaerobic biodegradability of lignocellulosic residues. While ultrasonication has been commonly applied as a pre-treatment of the feed substrate, in the present study a non-conventional process configuration based on recirculation of sonicated digestate to the biological reactor was evaluated at the lab-scale. Sonication tests were carried out at different applied energies ranging between 500 and 50,000kJ/kg TS. Batch anaerobic digestion tests were performed on samples prepared by mixing sonicated and untreated substrate at two different ratios (25:75 and 75:25 w/w). The results showed that when applied as a post-treatment of digestate, ultrasonication can positively affect the yield of anaerobic digestion, mainly due to the dissolution effect of complex organic molecules that have not been hydrolyzed by biological degradation. A good correlation was found between the CH4 production yield and the amount of soluble organic matter at the start of digestion tests. The maximum gain in biogas production was 30% compared to that attained with the unsonicated substrate, which was tentatively related to the type and concentration of the metabolic products.

  10. Anaerobic digestion of straw and corn stover: The effect of biological process optimization and pre-treatment on total bio-methane yield and energy performance.

    Science.gov (United States)

    Croce, Serena; Wei, Qiao; D'Imporzano, Giuliana; Dong, Renjie; Adani, Fabrizio

    2016-12-01

    Anaerobic digestion (AD) is a useful method for producing renewable energy/biofuel. Today, biogas production uses a large amount of energy crops (EC), with the effect of increasing AD costs and creating conflict between food/feed vs. energy use. A partial solution to this might be the substitution of EC with agricultural wastes, e.g. straw. Straw and corn stover are widely available in the world and approximately 1600millionMgyear(-1) of these substrates are available. Straw can be useful used for biogas production but its characteristics limit its performance so that sometimes the energetic balance can be negative. In this review, the limits for the conversion of this substrate into biogas were investigated and solutions/proposals for getting higher straw biogas production performance are reported. In addition, energetic balances for untreated and pre-treated substrates are reported, giving indicative evaluations of the sustainability of straw and corn stover use for biogas production.

  11. Optimization of the purification process of wine lees through anaerobic filter reactors. Optimizacion del proceso de depuracion de vinazas de vino mediante reactores tipo filtro anaerobio

    Energy Technology Data Exchange (ETDEWEB)

    Nebot Sanz, E.; Romero Garcia, L.I.; Quiroga Alonso, J.M.; Sales Marquez, D. (Departamento de Ingenieria Quimica, Universidad de Cadiz, Cadiz (Spain))

    1994-01-01

    In this work, the optimization of thermophilic anaerobic process, using Anaerobic Filter technology was studied. Feed of the Anaerobic Filter was wine-distillery wastewaters. The experiments developed were carried out at lab-scale downflow anaerobic filter reactors. Reactors were filled with a high porous plastic media (Flocor-R). The media support entities have a high surface/volume ratio. Test were run to determine the maximum organic load attainable in the system for wich both, the depurative efficiency and the methane production were optimum. Likewise, the effect of organic load on the anaerobic filter performance were studied. (Author) 15 refs. (Author)

  12. Anaerobic co-digestion of meat-processing by-products and sewage sludge - effect of hygienization and organic loading rate.

    Science.gov (United States)

    Luste, Sami; Luostarinen, Sari

    2010-04-01

    Anaerobic co-digestion of a mixture of animal by-products (ABP) from meat-processing industry and of sewage sludge was studied at 35 degrees Celsius for co-digesting such by-products in digesters at wastewater treatment plants. The three reactors were fed with ABP mixture and sewage sludge (1) in a ratio of 1:7 (v/v), (2) in the same ratio but with hygienization (70 degrees Celsius, 60 min) and (3) in a ratio of 1:3 (v/v). Hydraulic retention time (HRT) was decreased from 25 to 20 days and finally to 14 days, while organic loading rates (OLR) ranged from 1.8 to 4.0 kg VS/m(3) day. The highest specific methane yields were achieved with 20-days-HRT (1) 400 + or - 30, (2) 430 + or - 40, (3) 410 + or - 30 m(3) CH(4)/t VS. Hygienization improved methane production to a level above the highest OLR applied (feed ratio 1:3 (3)), while the quality of the digestate remained similar to the other reactors.

  13. Semi-continuous anaerobic co-digestion of sugar beet byproduct and pig manure: Effect of the organic loading rate (OLR) on process performance.

    Science.gov (United States)

    Aboudi, Kaoutar; Álvarez-Gallego, Carlos José; Romero-García, Luis Isidoro

    2015-10-01

    Anaerobic co-digestion of dried pellet of exhausted sugar beet cossettes (ESBC-DP) with pig manure (PM) was investigated in a semi-continuous stirred tank reactor (SSTR) under mesophilic conditions. Seven hydraulic retention times (HRT) from 20 to 5 days were tested with the aim to evaluate the methane productivities and volatile solids (VS) removal. The corresponding organic loading rates (OLR) ranged from 4.2 to 12.8 gVS/L(reactor) d. The findings revealed that highest system efficiency was achieved at an OLR of 11.2 gVS/L(reactor) d (6 days-HRT) with a methane production rate (MPR) and volatile solids (VS) reduction of 2.91 LCH4/L(reactor) d and 57.5%, respectively. The HRT of 5 days was found critical for the studied process, which leads to volatile fatty acids (VFA) accumulation and sharp drop in pH. However, the increase of HRT permits the recovery of system.

  14. The effects of operational and environmental variations on anaerobic wastewater treatment systems: a review

    Energy Technology Data Exchange (ETDEWEB)

    Leitao, R.C. [Embrapa Agroindustria Tropical (Brazilian Agricultural Research Corporation, Inst. of Tropical Agroindustry), Fortaleza (Brazil); Haandel, A.C. van [Federal University of Campina Grande (Brazil); Zeeman, G.; Lettinga, G. [Wageningen Univ. (Netherlands)

    2006-06-15

    With the aim of improving knowledge about the stability and reliability of anaerobic wastewater treatment systems, several researchers have studied the effects of operational or environmental variations on the performance of such reactors. In general, anaerobic reactors are affected by changes in external factors, but the severity of the effect is dependent upon the type, magnitude, duration and frequency of the imposed changes. The typical responses include a decrease in performance, accumulation of volatile fatty acids, drop in pH and alkalinity, change in biogas production and composition, and sludge washout. This review summarises the causes, types and effects of operational and environmental variation on anaerobic wastewater treatment systems. However, there still remain some unclear technical and scientific aspects that are necessary for the improvement of the stability and reliability of anaerobic processes. (author)

  15. Anaerobic Digestion of Buffalo Dung: Simulation of Process Kinetics

    Directory of Open Access Journals (Sweden)

    Abdul Razaque Sahito

    2015-01-01

    Full Text Available Assessment of kinetic of AD (Anaerobic Digestion is a beneficial practice to forecast the performance of the process. It is helpful in the design of AD vessels, substrate feeding and digestate exit systems. The aim of this work was to assess the kinetics of anaerobically digested buffalo dung at different quantities of water added. It comprises the assessment of the specific methane production on the basis of VS (Volatile Solids added in each reactor by using three first order models, i.e. the modified Gompertz model, the Cone model and the Exponential Curve Factor model. The analysis was tested by using the three statistical parameters, i.e. the coefficient of multiple determinations, the standard deviation of residuals and the Akaike?s Information Criteria. The result reveals that the Exponential Curve Factor model was the best model that described the experimental data well. Moreover, there was not a direct or indirect relation between the kinetic coefficients of the AD process with the varying total or volatile solid content

  16. Optimization of process parameters for production of volatile fatty acid, biohydrogen and methane from anaerobic digestion.

    Science.gov (United States)

    Khan, M A; Ngo, H H; Guo, W S; Liu, Y; Nghiem, L D; Hai, F I; Deng, L J; Wang, J; Wu, Y

    2016-11-01

    The anaerobic digestion process has been primarily utilized for methane containing biogas production over the past few years. However, the digestion process could also be optimized for producing volatile fatty acids (VFAs) and biohydrogen. This is the first review article that combines the optimization approaches for all three possible products from the anaerobic digestion. In this review study, the types and configurations of the bioreactor are discussed for each type of product. This is followed by a review on optimization of common process parameters (e.g. temperature, pH, retention time and organic loading rate) separately for the production of VFA, biohydrogen and methane. This review also includes additional parameters, treatment methods or special additives that wield a significant and positive effect on production rate and these products' yield.

  17. Extension of anaerobic digestion model no. 1 with the processes of sulphate reduction

    NARCIS (Netherlands)

    Fedorovich, V.; Lens, P.N.L.; Kalyuzhnyi, S.

    2003-01-01

    In the present work, the Anaerobic Digestion Model No. 1 (ADM1) for computer simulation of anaerobic processes was extended to the processes of sulfate reduction. The upgrade maintained the structure of ADM1 and included additional blocks describing sulfate-reducing processes (multiple reaction stoi

  18. Application of Hydrothermal Treatment to High Concentrated Sewage Sludge for Anaerobic Digestion Process

    Directory of Open Access Journals (Sweden)

    M. Orikawa

    2013-10-01

    Full Text Available Tomato and seaweed were produced by utilizing CO2 and heat discharged from power generation using biogas in Toyogawa biomass park, Japan. The biogas was obtained by anaerobic digestion with hydrothermal treatment. The hydrothermal treatment was applied to the high concentrated sewage sludge (22 % total solids (TS dewatered sludge. The purpose of this study is to clarify the effect of hydrothermal treatment on the qualities of high concentrated sewage sludge, by analyzing particulate organic carbon (POC and dissolved organic carbon (DOC. The hydrothermal treatment was investigated under 10-60 min of treatment time, 180-200 °C of temperature, 10-22 %-TS of sewage sludge concentration. The results showed that the DOC in each conditions increased through hydrothermal treatment. The highest DOC obtained was 67 % of total carbon concentration, when the temperature was 180 °C, treatment time was 60 min and sewage sludge concentration was 10 %-TS. Furthermore, the viscosity of treated sewage sludge was decreased by hydrothermal treatment. In batch anaerobic digestion test, methane gas production was confirmed. In addition, this study evaluated the energy balance of this system. Thus, the results of this study indicated that the possibility of application of hydrothermal treatment to high concentrated sewage sludge for anaerobic digestion process. Keywords: anaerobic reaction, hydrothermal treatment, sewage sludge, solubilization

  19. Effects of Oxytetracycline on Methane Production and the Microbial Communities During Anaerobic Digestion of Cow Manure

    Institute of Scientific and Technical Information of China (English)

    KE Xin; WANG Chun-yong; LI Run-dong; ZHANG Yun

    2014-01-01

    The effects of different concentrations of oxytetracycline (OTC) on the dynamics of bacterial and archaeal communities during the mesophilic anaerobic digestion (37°C) of cow manure were investigated. Before anaerobic digestion, OTC was added to digesters at concentrations of 20, 50, and 80 mg L-1, respectively. Compared with no-antibiotic control, all methane productions underwent different levels of inhibition at different concentrations of OTC. Changes in the bacterial and archaeal communities were discussed by using PCR-denaturing gradient gel electrophoresis (DGGE). Results showed that OTC affected the richness and diversity of bacterial and archaeal communities. The bacterial genus Flavobacterium and an uncultured bacterium (JN256083.1) were detected throughout the entire process of anaerobic digestion and seemed to be the functional bacteria. Methanobrevibacter boviskoreani and an uncultured archaeon (FJ230982.1) dominated the archaeal communities during anaerobic digestion. These microorganisms may have high resistance to OTC and may play vital roles in methane production.

  20. Instrumentation and control of anaerobic digestion processes: A review and some research challenges

    NARCIS (Netherlands)

    Jimenez, J.; Latrille, E.; Harmand, J.; Robles, A.; Ferrer, J.; Gaida, D.; Wolf, C.; Mairet, F.; Bernard, O.; Alcaraz-Gonzalez, V.; Mendez-Acosta, H.; Zitomer, D.; Totzke, D.; Spanjers, H.; Jacobi, F.; Guwy, A.; Dinsdale, R.; Premier, G.; Mazhegrane, S.; Ruiz-Filippi, G.; Seco, A.; Ribeiro, T.; Pauss, A.; Steyer, J.P.

    2015-01-01

    To enhance energy production from methane or resource recovery from digestate, anaerobic digestion processes require advanced instrumentation and control tools. Over the years, research on these topics has evolved and followed the main fields of application of anaerobic digestion processes: from mun

  1. Effect of humic acid in leachate on specific methanogenic activity of anaerobic granular sludge.

    Science.gov (United States)

    Guo, Mengfei; Xian, Ping; Yang, Longhui; Liu, Xi; Zhan, Longhui; Bu, Guanghui

    2015-01-01

    In order to find out the effects of humic acid (HA) in anaerobic-treated landfill leachate on granular sludge, the anaerobic biodegradability of HA as well as the influences of HA on the total cumulative methane production, the anaerobic methanization process and the specific methanogenic activity (SMA) of granular sludge are studied in this paper. Experimental results show that as a non-biodegradable organic pollutant, HA is also difficult to be decomposed by microbes in the anaerobic reaction process. Presence of HA and changes in the concentration have no significant influences on the total cumulative methane production and the anaerobic methanization process of granular sludge. Besides, the total cumulative methane production cannot reflect the inhibition of toxics on the methanogenic activity of granular sludge on the premise of sufficient reaction time. Results also show that HA plays a promoting role on SMA of granular sludge. Without buffering agent the SMA value increased by 19.2% on average due to the buffering and regulating ability of HA, while with buffering agent the SMA value increased by 5.4% on average due to the retaining effect of HA on the morphology of the sludge particles. However, in the presence of leachate the SMA value decreased by 27.6% on average, because the toxic effect of the toxics in the leachate on granular sludge is much larger than the promoting effect of HA.

  2. Impact of agricultural activities on anaerobic processes in stream sediments

    Science.gov (United States)

    Schade, J. D.; Ludwig, S.; Nelson, L. C.; Porterfield, J.; Sather, K. L.; Songpitak, M.; Spawn, S.; Weigel, B.

    2013-12-01

    Streams draining agriculture watersheds are subject to significant anthropogenic impacts, including sedimentation from soil erosion and high nitrate input from heavy fertilizer application. Sedimentation degrades habitat and can reduce hydrologic exchange between surface and subsurface waters. Disconnecting surface and subsurface flow reduces oxygen input to hyporheic water, increasing the extent of anoxic zones in stream sediments and creating hotspots for anaerobic processes like denitrification and methanogenesis that can be important sources of nitrous oxide and methane, both powerful greenhouse gases. Increased nitrate input may influence greenhouse gas fluxes from stream sediments by stimulating rates of denitrification and potentially reducing rates of methanogenesis, either through direct inhibition or by increasing competition for organic substrates from denitrifying bacteria. We hypothesized that accumulation of fine sediments in stream channels would result in high rates of methanogenesis in stream sediments, and that increased nitrate input from agricultural runoff would stimulate denitrification and reduce rates of methane production. Our work focused on streams in northern and central Minnesota, in particular on Rice Creek, a small stream draining an agricultural watershed. We used a variety of approaches to test our hypotheses, including surveys of methane concentrations in surface waters of streams ranging in sediment type and nitrate concentration, bottle incubations of sediment from several sites in Rice Creek, and the use of functional gene probes and RNA analyses to determine if genes for these processes are present and being expressed in stream sediments. We found higher methane concentrations in surface water from streams with large deposits of fine sediments, but significantly less methane in these streams when nitrate concentrations were high. We also found high potential for both methanogenesis and denitrification in sediment incubations

  3. [Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography].

    Science.gov (United States)

    Ito, Kazuaki; Sakamoto, Jun; Nagaoka, Kazuya; Takayama, Yohichi; Kanahori, Takashi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2012-04-01

    The analysis of seven aliphatic carboxylic acids (formic, acetic, propionic, iso-butyric, n-butyric, iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid, perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection. The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column (TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column (TSKgel Super IC-A/C). Good separation was performed on the TSKgel SCX in shorter retention times. For the TSKgel Super IC-A/C, peak shape of the acids was sharp and symmetrical in spite of longer retention times. In addition, the mutual separation of the acids was good except for iso- and n-butyric acids. The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series), lower concentrations of PFBA and sulfuric acid as eluents, non-suppressed conductivity detection and UV detection at 210 nm. This analysis was applied to anaerobic digestion process waters. The chromatograms with conductivity detection were relatively simpler compared with those of UV detection. The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

  4. Modeling of two-phase anaerobic process treating traditional Chinese medicine wastewater with the IWA Anaerobic Digestion Model No. 1.

    Science.gov (United States)

    Chen, Zhaobo; Hu, Dongxue; Zhang, Zhenpeng; Ren, Nanqi; Zhu, Haibo

    2009-10-01

    The aim of the study was to implement a mathematical model to simulate two-phase anaerobic digestion (TPAD) process which consisted of an anaerobic continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket (UASB) reactor in series treating traditional Chinese medicine (TCM) wastewater. A model was built on the basis of Anaerobic Digestion Model No. 1 (ADM1) while considering complete mixing model for the CSTR, and axial direction discrete model and mixed series connection model for the UASB. The mathematical model was implemented with the simulation software package MATLABTM/Simulinks. System performance, in terms of COD removal, volatile fatty acids (VFA) accumulation and pH fluctuation, was simulated and compared with the measured values. The simulation results indicated that the model built was able to well predict the COD removal rate (-4.8-5.0%) and pH variation (-2.9-1.4%) of the UASB reactor, while failed to simulate the CSTR performance. Comparing to the measured results, the simulated acetic acid concentration of the CSTR effluent was underpredicted with a deviation ratios of 13.8-23.2%, resulting in an underprediction of total VFA and COD concentrations despite good estimation of propionic acid, butyric acid and valeric acid. It is presumed that ethanol present in the raw wastewater was converted into acetic acid during the acidification process, which was not considered by the model. Additionally, due to the underprediction of acetic acid the pH of CSTR effluent was overestimated.

  5. Early warning indicators for monitoring the process failure of anaerobic digestion system of food waste.

    Science.gov (United States)

    Li, Lei; He, Qingming; Wei, Yunmei; He, Qin; Peng, Xuya

    2014-11-01

    To determine reliable state parameters which could be used as early warning indicators of process failure due to the acidification of anaerobic digestion of food waste, three mesophilic anaerobic digesters of food waste with different operation conditions were investigated. Such parameters as gas production, methane content, pH, concentrations of volatile fatty acid (VFA), alkalinity and their combined indicators were evaluated. Results revealed that operation conditions significantly affect the responses of parameters and thus the optimal early warning indicators of each reactor differ from each other. None of the single indicators was universally valid for all the systems. The universally valid indicators should combine several parameters to supply complementary information. A combination of total VFA, the ratio of VFA to total alkalinity (VFA/TA) and the ratio of bicarbonate alkalinity to total alkalinity (BA/TA) can reflect the metabolism of the digesting system and realize rapid and effective early warning.

  6. The effect of motivational music on wingate anaerobic test performance

    Directory of Open Access Journals (Sweden)

    Özkan Işık

    2015-09-01

    Full Text Available The aim of this study is to examine the effect of the motivational music on the Wingate Anaerobic Test (WAnT performance. 16 male students who studied at School of Physical Education and Sports, Kocatepe University participated in the study voluntarily. After demographic characteristics of the voluntaries [age, height, body weight (BW, body mass index (BMI] were measured without music (pre-test and with motivational music [>120 bpm (beats per minute] conditions (post-test. For the analyses of the data; Wilcoxon Rank Test was used in order to detect the difference among the variables. As a result of the measurements taken in with and without music conditions; it was found out that there was a statistically significant difference on behalf of condition with music in terms of maximum anaerobic power (MaxAP, maximum anaerobic capacity (MAC, relative anaerobic power (RAP, relative anaerobic capacity (RAC and fatigue index (FI values (p0,05. It was determined that the motivational music has positive effects on the WAnT performance. However; although it was seen that motivational music increased the WAnT performance, we were of the opinion that this effect emerged thanks to the increased psycho-physiological factors caused by music.

  7. Microbiology, ecology and application of the nitrite-dependent anaerobic methane oxidation process

    Directory of Open Access Journals (Sweden)

    Li-Dong eShen

    2012-07-01

    Full Text Available Nitrite-dependent anaerobic methane oxidation (n-damo, which couples the anaerobic oxidation of methane to denitrification, is a recently discovered process observed in Candidatus Methylomirabilis oxyfera. M. oxyfera is affiliated with the NC10 phylum, a phylum having no members in pure culture. Based on the isotopic labeling experiments, it is hypothesized that M. oxyfera has an unusual intra-aerobic pathway for the production of oxygen via the dismutation of nitric oxide into dinitrogen gas and oxygen. In addition, the bacterial species has a unique ultrastructure that is distinct from that of other previously described bacterial shapes. M. oxyfera-like sequences have been recovered from different natural habitats, suggesting that the n-damo process potentially contributes to global carbon and nitrogen cycles. The n-damo process is an ecological process that can reduce the greenhouse effect, as methane is more effective in heat-trapping than carbon dioxide. The n-damo process, which uses methane instead of organic matter to drive denitrification, is also an economical nitrogen removal process because methane is a relatively inexpensive electron donor. This mini-review summarizes the peculiar microbiology of M. oxyfera and discusses the potential ecological importance and engineering application of the n-damo process.

  8. Microbiology, ecology, and application of the nitrite-dependent anaerobic methane oxidation process.

    Science.gov (United States)

    Shen, Li-Dong; He, Zhan-Fei; Zhu, Qun; Chen, Dong-Qing; Lou, Li-Ping; Xu, Xiang-Yang; Zheng, Ping; Hu, Bao-Lan

    2012-01-01

    Nitrite-dependent anaerobic methane oxidation (n-damo), which couples the anaerobic oxidation of methane to denitrification, is a recently discovered process mediated by "Candidatus Methylomirabilis oxyfera." M. oxyfera is affiliated with the "NC10" phylum, a phylum having no members in pure culture. Based on the isotopic labeling experiments, it is hypothesized that M. oxyfera has an unusual intra-aerobic pathway for the production of oxygen via the dismutation of nitric oxide into dinitrogen gas and oxygen. In addition, the bacterial species has a unique ultrastructure that is distinct from that of other previously described microorganisms. M. oxyfera-like sequences have been recovered from different natural habitats, suggesting that the n-damo process potentially contributes to global carbon and nitrogen cycles. The n-damo process is a process that can reduce the greenhouse effect, as methane is more effective in heat-trapping than carbon dioxide. The n-damo process, which uses methane instead of organic matter to drive denitrification, is also an economical nitrogen removal process because methane is a relatively inexpensive electron donor. This mini-review summarizes the peculiar microbiology of M. oxyfera and discusses the potential ecological importance and engineering application of the n-damo process.

  9. Microbiological Hydrogen Production by Anaerobic Fermentation and Photosynthetic Process

    Energy Technology Data Exchange (ETDEWEB)

    Asada, Y.; Ohsawa, M.; Nagai, Y.; Fukatsu, M.; Ishimi, K.; Ichi-ishi, S.

    2009-07-01

    Hydrogen gas is a clean and renewable energy carrier. Microbiological hydrogen production from glucose or starch by combination used of an anaerobic fermenter and a photosynthetic bacterium, Rhodobacter spheroides RV was studied. In 1984, the co-culture of Clostridium butyricum and RV strain to convert glucose to hydrogen was demonstrated by Miyake et al. Recently, we studied anaerobic fermentation of starch by a thermophilic archaea. (Author)

  10. In-Situ Anaerobic Biosurfactant Production Process For Remediation Of DNAPL Contamination In Subsurface Aquifers

    Science.gov (United States)

    Albino, J. D.; Nambi, I. M.

    2009-12-01

    Microbial Enhanced Oil Recovery (MEOR) and remediation of aquifers contaminated with hydrophobic contaminants require insitu production of biosurfactants for mobilization of entrapped hydrophobic liquids. Most of the biosurfactant producing microorganisms produce them under aerobic condition and hence surfactant production is limited in subsurface condition due to lack of oxygen. Currently bioremediation involves expensive air sparging or excavation followed by exsitu biodegradation. Use of microorganisms which can produce biosurfactants under anaerobic conditions can cost effectively expedite the process of insitu bioremediation or mobilization. In this work, the feasibility of anaerobic biosurfactant production in three mixed anaerobic cultures prepared from groundwater and soil contaminated with chlorinated compounds and municipal sewage sludge was investigated. The cultures were previously enriched under complete anaerobic conditions in the presence of Tetrachloroethylene (PCE) for more than a year before they were studied for biosurfactant production. Biosurfactant production under anaerobic conditions was simulated using two methods: i) induction of starvation in the microbial cultures and ii) addition of complex fermentable substrates. Positive result for biosurfactant production was not observed when the cultures were induced with starvation by adding PCE as blobs which served as the only terminal electron acceptor. However, slight reduction in interfacial tension was noticed which was caused by the adherence of microbes to water-PCE interface. Biosurfactant production was observed in all the three cultures when they were fed with complex fermentable substrates and surface tension of the liquid medium was lowered below 35 mN/m. Among the fermentable substrates tested, vegetable oil yielded highest amount of biosurfactant in all the cultures. Complete biodegradation of PCE to ethylene at a faster rate was also observed when vegetable oil was amended to the

  11. A new model for anaerobic processes of up-flow anaerobic sludge blanket reactors based on cellular automata

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Ahring, Birgitte Kiær

    2002-01-01

    characteristics and lead to different reactor behaviour. A dynamic mathematical model has been developed for the anaerobic digestion of a glucose based synthetic wastewater in UASB reactors. Cellular automata (CA) theory has been applied to simulate the granule development process. The model takes...... into consideration that granule diameter and granule microbial composition are functions of the reactor operational parameters and is capable of predicting the UASB performance and the layer structure of the granules....

  12. Anaerobic methanotrophy in tidal wetland: Effects of electron acceptors

    Science.gov (United States)

    Lin, Li-Hung; Yu, Zih-Huei; Wang, Pei-Ling

    2016-04-01

    Wetlands have been considered to represent the largest natural source of methane emission, contributing substantially to intensify greenhouse effect. Despite in situ methanogenesis fueled by organic degradation, methanotrophy also plays a vital role in controlling the exact quantity of methane release across the air-sediment interface. As wetlands constantly experience various disturbances of anthropogenic activities, biological burrowing, tidal inundation, and plant development, rapid elemental turnover would enable various electron acceptors available for anaerobic methanotrophy. The effects of electron acceptors on stimulating anaerobic methanotrophy and the population compositions involved in carbon transformation in wetland sediments are poorly explored. In this study, sediments recovered from tidally influenced, mangrove covered wetland in northern Taiwan were incubated under the static conditions to investigate whether anaerobic methanotrophy could be stimulated by the presence of individual electron acceptors. Our results demonstrated that anaerobic methanotrophy was clearly stimulated in incubations amended with no electron acceptor, sulfate, or Fe-oxyhydroxide. No apparent methane consumption was observed in incubations with nitrate, citrate, fumarate or Mn-oxides. Anaerobic methanotrophy in incubations with no exogenous electron acceptor appears to proceed at the greatest rates, being sequentially followed by incubations with sulfate and Fe-oxyhydroxide. The presence of basal salt solution stimulated methane oxidation by a factor of 2 to 3. In addition to the direct impact of electron acceptor and basal salts, incubations with sediments retrieved from low tide period yielded a lower rate of methane oxidation than from high tide period. Overall, this study demonstrates that anaerobic methanotrophy in wetland sediments could proceed under various treatments of electron acceptors. Low sulfate content is not a critical factor in inhibiting methane

  13. Thermo- and mesophilic anaerobic digestion of wheat straw by the upflow anaerobic solid-state (UASS) process.

    Science.gov (United States)

    Pohl, Marcel; Mumme, Jan; Heeg, Kathrin; Nettmann, Edith

    2012-11-01

    In this experimental work, the feasibility of wheat straw as a feedstock for biogas production is investigated using the newly developed upflow anaerobic solid-state (UASS) process. With the analytical emphasis placed on methane and metabolite production, both mesophilic and thermophilic 39 L UASS reactors were operated for 218 days at an organic loading rate of 2.5 g(VS)L(-1)d(-1) using wheat straw as sole substrate. For improved methanization of soluble metabolites, each UASS reactor was connected to an individual 30 L anaerobic filter (AF). During steady state thermophilic straw digestion was found to have a 36% higher methane yield (0.165 L g(VS)(-1)) whereas the hydrolysis rate constant increased by 106% (0.066 d(-1)).

  14. Biohydrogen production from diary processing wastewater by anaerobic biofilm reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rios-Gonzalez, L.J.; Moreno-Davila, I.M.; Rodriguez-Martinez, J.; Garza-Garcia, Y. [Universidad Autonoma de Coahuila, Saltillo, Coahuila (Mexico)]. E-mail: leopoldo.rios@mail.uadec.mx

    2009-09-15

    This article describes biological hydrogen production from diary wastewater via anaerobic fermentation using pretreated heat shock (100 degrees Celsius, 30 min.) and acid (pH 3.0, 24 h) treatment procedures to selectively enrich the hydrogen producing mixed consortia prior to inoculation to batch reactors. Bioreactor used for immobilization consortia was operated at mesophilic (room) temperature (20{+-}3 degrees Celsius), under acidophilic conditions (pH 4.0-4.5), HRT (2h), and a natural support for generate hydrogen producing mixed consortia biofilm: Opuntia imbricata. Reactor was initially operated with sorbitol (5g/L) for 60 days of operation. Batch tests were conducted using 20{+-}0.02g of natural support with biofilm. Batch experiments were conducted to investigate the effect of COD (2.9-21.1 g-COD/L), at initial pH of 7.0, 32{+-}1 degrees Celsius. Maximum hydrogen yield was obtained at 21.1 g-COD/L. Experiments of pH effect were conducted using the optimal substrate concentration (21.2 g-COD/L), at pH 4 to 7 and 11.32 (pH diary wastewater) ,and 32{+-}1 degrees Celsius. Experiments results indicate the optimum initial cultivation was pH 4.0, but we can consider also a stable hydrogen production at pH 11.32 (pH diary wastewater), so we can avoid to fit the pH, and use diary wastewater as it left the process of cheese manufacture. The operational pH of 4.0 is 1.5 units below that of previously reported hydrogen producing organisms. The influence of the effect of temperature were conducted using the optimal substrate concentration (21.2 g-COD/L), two pH levels: 4.0 and 11.32, and four different temperatures: 16{+-}3 degrees Celsius (room temperature), 3 C, 45{+-}1 degrees Celsius y 55{+-}1 degrees Celsius.Optimal temperature for hydrogen production from diary wastewater at pH 4.0 was 55{+-}1 degrees Celsius, and for pH 11.32 was 16{+-}3 degrees Celsius.Therefore, the results suggests biofilm reactors in a natural support like Opuntia imbricata have good potential

  15. Characteristics of high-sulfate wastewater treatment by two-phase anaerobic digestion process with Jet-loop anaerobic fluidized bed

    Institute of Scientific and Technical Information of China (English)

    WEI Chao-hai; WANG Wen-xiang; DENG Zhi-yi; WU Chao-fei

    2007-01-01

    A new anaerobic reactor,Jet-loop anaerobic fluidized bed(JLAFB),was designed for treating high-sulfate wastewater.The treatment characteristics,including the effect of influent COD/SO42- ratio and alkalinity and sulfide inhibition in reactors,were discussed for a JLAFB and a general anaerobic fluidized bed(AFB)reactor used as sulfate-reducing phase and methane-producing phase,respectively,in two-phase anaerobic digestion process.The formation of granules in the two reactors was also examined.The results indicated that COD and sulfate removal had different demand of influent COD/S042- ratios.When total COD removal Was up to 85%,the ratio was only required up to 1.2,whereas,total sulfate removal up to 95%required it exceeding 3.0.The alkalinity in the two reactors increased linearly with the growth of influent alkalinity.Moreover,the change of influent alkalinity had no significant effect on pH and volatile fatty acids(VFA)in the two reactors.Influent alkalinity kept at 400-500 mg/t,could meet the requirement of the treating process.The JLAFB reactor had great advantage in avoiding sulfide and free-H2S accumulation and toxicity inhibition on microorganisms.When sulfate loading rate was up to 8.1 kg/(m3·d),the sulfide and free-H2S concentrations in JLAFB reactor were 58.6 and 49.7 mg/L,respectively.Furthermore,the granules,with offwhite color,ellipse shape and diameters of 1.0-3.0 mm,could be developed in JLAFB reactor.In granules,different groups of bacteria were distributed in different layers,and some inorganic metal compounds such as Fe,Ca,Mg etc.were found.

  16. Mechanisms of granular activated carbon anaerobic fluidized-bed process for treating phenols wastewater

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Granular activated carbon (GAC) anaerobic fluidized-bed reactor was applied to treating phenols wastewater. When influent phenol concentration was 1000 mg/L, volume loadings of phenol and CODCr were 0.39 kg/(m3*d) and 0.98 kg/(m3*d), their removal rates were 99.9% and 96.4% respectively. From analyzing above results, the main mechanisms of the process are that through fluidizing GAC, its adsorption is combined with biodegradation, both activities are brought into full play, and phenol in wastewater is effectively decomposed. Meanwhile problems concerning gas-liquid separation and medium plugging are well solved.

  17. Study of the Process of Hydraulic Mixing in Anaerobic Digester of Biogas Plant

    Directory of Open Access Journals (Sweden)

    Karaeva Julia V.

    2015-03-01

    Full Text Available Two systems of hydraulic mixing in a vertical cylindrical anaerobic digester: standard and modernised are discussed in the paper. Numerical investigations that were carried out are focused on a study of hydrodynamic processes in an aerobic digester using two various systems of hydraulic mixing as well as on analysis of the efficiency of methane fermentation process accomplished under different geometric parameters of an anaerobic digester and systems of hydraulic mixing.

  18. Involvement of protozoa in anaerobic wastewater treatment process.

    Science.gov (United States)

    Priya, M; Haridas, Ajit; Manilal, V B

    2007-12-01

    It is only very rarely recognised in literature that anaerobic reactors may contain protozoa in addition to various bacterial and archeal groups. The role of protozoa in anaerobic degradation was studied in anaerobic continuous stirred tank reactors (CSTR) and batch tests. Anaerobic protozoa, especially the ciliated protozoa, have direct influence on the performance of CSTR at all organic loading rates (1-2g CODl(-1)d(-1)) and retention times (5-10 days). The studies revealed that chemical oxygen demand (COD) removal is strongly correlated to ciliate density in CSTR fed with oleate (suspended COD) and acetate (soluble COD). There was no significant difference in COD removal between reactors fed suspended COD and those fed soluble COD. However, the diversity and number of ciliates is greater in CSTR fed with particulate feed. The mixed liquor suspended solids (MLSS) representing biomass was significantly lower (16-34%) in CSTR with protozoa. In batch tests, increased COD removal and methane production was observed in sludge having ciliates as compared with sludge without protozoa. Methane production increased linearly with number of ciliates (R(2)=0.96) in batch tests with protozoa. Direct utilization of COD by flagellates and ciliates was observed in bacteria-suppressed cultures. The technological importance of these results is that reactors with protozoa-rich sludge can enhance the rate of mineralization of complex wastewater, especially wastewater containing particulate COD.

  19. Anaerobic Digestion. Instructor's Guide. Biological Treatment Process Control.

    Science.gov (United States)

    Carnegie, John W., Ed.

    This instructor's guide contains materials needed to teach a four-lesson unit on anaerobic digestion control. These materials include: (1) unit overview; (2) lesson plans; (3) lecture outlines; (4) student worksheets for each lesson (with answers); and (5) two copies of a final quiz (with and without answers). Lesson 1 is a review of the theory of…

  20. Effective distribution of emulsified edible oil for enhanced anaerobic bioremediation

    Science.gov (United States)

    Borden, Robert C.

    2007-10-01

    Recent laboratory and field studies have shown that injection of emulsified edible oils can provide an effective, low-cost alternative for stimulating anaerobic biodegradation processes. A pilot-scale permeable reactive bio-barrier (PRBB) was installed at a perchlorate and chlorinated solvent impacted site by injecting 380 L of commercially available emulsion (EOS ®) containing emulsified soybean oil, food-grade surfactants, lactate, and yeast extract through ten direct push injection wells over a two day period. Soil cores collected six months after emulsion injection indicate the oil was distributed up to 5 m downgradient of the injection wells. A previously developed emulsion transport model was used to simulate emulsion transport and retention using independently estimated model parameters. While there was considerable variability in the soil sampling results, the model simulations generally agreed with the observed oil distribution at the field site. Model sensitivity analyses indicate that increasing the injection flow rate or diluting the oil with more water will have little effect on final oil distribution in the aquifer. The only effective approach for enhancing the spread of emulsified oil away from the injection well appears to be injecting a greater mass of oil.

  1. Analysis of aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography

    Institute of Scientific and Technical Information of China (English)

    Kazuaki ITO; Kazuhiko TANAKA; Jun SAKAMOTO; Kazuya NAGAOKA; Yohichi TAKAYAMA; Takashi KANAHORI; Hiroshi SUNAHARA; Tsuneo HAYASHI; Shinji SATO; Takeshi HIROKAWA

    2012-01-01

    The analysis of seven aliphatic carboxylic acids ( formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents (benzoic acid,perfluorobutyric acid (PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet (UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column ( TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column ( TSKgel Super IC-A/C ).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso- and n-butyric acids.The better separation and good detection was achieved by using the two columns (TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

  2. Aerobic vs anaerobic exercise training effects on the cardiovascular system.

    Science.gov (United States)

    Patel, Harsh; Alkhawam, Hassan; Madanieh, Raef; Shah, Niel; Kosmas, Constantine E; Vittorio, Timothy J

    2017-02-26

    Physical exercise is one of the most effective methods to help prevent cardiovascular (CV) disease and to promote CV health. Aerobic and anaerobic exercises are two types of exercise that differ based on the intensity, interval and types of muscle fibers incorporated. In this article, we aim to further elaborate on these two categories of physical exercise and to help decipher which provides the most effective means of promoting CV health.

  3. Aerobic vs anaerobic exercise training effects on the cardiovascular system

    Science.gov (United States)

    Patel, Harsh; Alkhawam, Hassan; Madanieh, Raef; Shah, Niel; Kosmas, Constantine E; Vittorio, Timothy J

    2017-01-01

    Physical exercise is one of the most effective methods to help prevent cardiovascular (CV) disease and to promote CV health. Aerobic and anaerobic exercises are two types of exercise that differ based on the intensity, interval and types of muscle fibers incorporated. In this article, we aim to further elaborate on these two categories of physical exercise and to help decipher which provides the most effective means of promoting CV health. PMID:28289526

  4. Suitability of anaerobic digestion effluent as process water for corn fuel ethanol fermentation.

    Science.gov (United States)

    Wang, Ke; Zhang, Jian-Hua; Liu, Pei; Mao, Zhong-Gui

    2014-01-01

    A corn fuel ethanol plant integrated with anaerobic digestion treatment of thin stillage increases the net energy balance. Furthermore, the anaerobic digestion effluent (ADE) can be reused as a potential substitute for process water in the ethanol fermentation. In this study, the suitability of ADE as process water for corn ethanol fermentation was investigated by analyzing the potential inhibitory components in the ADE. It was found that ammonium influenced the growth and metabolism of Saccharomyces cerevisiae. Maximum ethanol production was obtained when the concentration of ammonium nitrogen was 200 mg/L, and ammonium could replace urea as the nitrogen source for S. cerevisiae under this concentration. In the ethanol fermentation with a higher concentration of ammonium, more glycerol was produced, thereby resulting in the decrease of ethanol production. In addition, components except ammonium in the ADE caused no inhibition to ethanol production. These results suggest that ADE could be reused as process water for corn ethanol fermentation without negative effect when ammonium concentration is well controlled.

  5. Effect of methanogenic substrates on anaerobic oxidation of methane and sulfate reduction by an anaerobic methanotrophic enrichment.

    KAUST Repository

    Meulepas, Roel J W

    2010-05-06

    Anaerobic oxidation of methane (AOM) coupled to sulfate reduction (SR) is assumed to be a syntrophic process, in which methanotrophic archaea produce an interspecies electron carrier (IEC), which is subsequently utilized by sulfate-reducing bacteria. In this paper, six methanogenic substrates are tested as candidate-IECs by assessing their effect on AOM and SR by an anaerobic methanotrophic enrichment. The presence of acetate, formate or hydrogen enhanced SR, but did not inhibit AOM, nor did these substrates trigger methanogenesis. Carbon monoxide also enhanced SR but slightly inhibited AOM. Methanol did not enhance SR nor did it inhibit AOM, and methanethiol inhibited both SR and AOM completely. Subsequently, it was calculated at which candidate-IEC concentrations no more Gibbs free energy can be conserved from their production from methane at the applied conditions. These concentrations were at least 1,000 times lower can the final candidate-IEC concentration in the bulk liquid. Therefore, the tested candidate-IECs could not have been produced from methane during the incubations. Hence, acetate, formate, methanol, carbon monoxide, and hydrogen can be excluded as sole IEC in AOM coupled to SR. Methanethiol did inhibit AOM and can therefore not be excluded as IEC by this study.

  6. Microbiology, ecology, and application of the nitrite-dependent anaerobic methane oxidation process

    OpenAIRE

    Li-Dong eShen; Bao-lan eHu

    2012-01-01

    Nitrite-dependent anaerobic methane oxidation (n-damo), which couples the anaerobic oxidation of methane to denitrification, is a recently discovered process observed in Candidatus Methylomirabilis oxyfera. M. oxyfera is affiliated with the NC10 phylum, a phylum having no members in pure culture. Based on the isotopic labeling experiments, it is hypothesized that M. oxyfera has an unusual intra-aerobic pathway for the production of oxygen via the dismutation of nitric oxide into dinitrogen ga...

  7. Thermophilic anaerobic fermentation of olive pulp for hydrogen and methane production: modelling of the anaerobic digestion process

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Skiadas, Ioannis V.; Ahring, Birgitte Kiær;

    2006-01-01

    The present study investigates the thermophilic biohydrogen and methane production from olive pulp, which is the semi-solid. residue coming from the two-phase processing of olives. It focussed on: a) production of methane from the raw olive pulp; b) anaerobic bio-production of hydrogen from...... were performed. The hydrogen potential of the olive pulp amounted to 1.6 mmole H-2 per g TS. The methane potential of the raw olive pulp and hydrogen-effluent was as high as 19 mmole CH4 per g TS suggesting that: a) olive pulp is a suitable substrate for methane production; and b) biohydrogen...

  8. Effect of Different Carriers on Anaerobic Ammonium Oxidation Process%不同载体材料对厌氧氨氧化效果影响的研究

    Institute of Scientific and Technical Information of China (English)

    赵旭飞; 龚逸; 赖玮毅; 王一渌; 周伟丽

    2012-01-01

    文章分别采用水性聚氨酯(WPU)和活性炭2种材料作为生物载体,在2个不同的上流式厌氧污泥床(UASB)反应器中接种包埋污泥和生物活性炭,采用人工配水进行连续实验,观测厌氧氨氧化反应器启动过程中各种含氮化合物的变化,以考察不同载体材料对厌氧氨氧化过程的影响.文章在生物活性炭反应器中成功驯化了采自污水处理厂的普通厌氧污泥,证明了从环境中驯化培养厌氧氨氧化菌的可能性.通过2个阶段中脱氮效率的比较,发现以水性聚氨酯包埋材料作为未驯化细菌载体并无明显优势,反而成为传质的障碍;而采用生物活性炭则可以迅速达到提高局部生物量、聚集功能菌、屏蔽不利环境的干扰等作用,是理想的微生物载体.%To investigate the effect of different carriers on process of anaerobic ammonia oxidation, two types of materials including water-bone polyurethane (WPU) and activated carbon, were used for microbial immobilization in two different UASB reactors. The synthetic wastewater containing ammonia and nitrite was applied as raw water and variation of nitrogen compounds was analyzed. The study verified the possibility of domesticating anaerobic ammonium oxidation bacteria from the environment in biological nctivated carbon (BAC) system. The comparison of nitrogen removal efficiency in different running stages indicated that the immobilized sludge had no distinct advantage in reactor start-up as it might have become the obstacle of mass transfer, while the activated carbon proved to be an ideal microbial carrier due to synergistic effect of contaminant adsorption, bacterial aggregation and microbial degradation, combined with its protection of microorganisms from deleterious surroundings.

  9. Trace metal pyritization variability in response to mangrove soil aerobic and anaerobic oxidation processes.

    Science.gov (United States)

    Machado, W; Borrelli, N L; Ferreira, T O; Marques, A G B; Osterrieth, M; Guizan, C

    2014-02-15

    The degree of iron pyritization (DOP) and degree of trace metal pyritization (DTMP) were evaluated in mangrove soil profiles from an estuarine area located in Rio de Janeiro (SE Brazil). The soil pH was negatively correlated with redox potential (Eh) and positively correlated with DOP and DTMP of some elements (Mn, Cu and Pb), suggesting that pyrite oxidation generated acidity and can affect the importance of pyrite as a trace metal-binding phase, mainly in response to spatial variability in tidal flooding. Besides these aerobic oxidation effects, results from a sequential extraction analyses of reactive phases evidenced that Mn oxidized phase consumption in reaction with pyrite can be also important to determine the pyritization of trace elements. Cumulative effects of these aerobic and anaerobic oxidation processes were evidenced as factors affecting the capacity of mangrove soils to act as a sink for trace metals through pyritization processes.

  10. Anaerobic treatment for C and S removal in 'zero-discharge' paper mills: effects of process design on S removal efficiencies.

    NARCIS (Netherlands)

    Lier, van J.B.; Lens, P.N.L.; Hulshoff Pol, L.W.

    2001-01-01

    Stringent environmental laws in Europe and Northern America lead to the development towards closure of the process water streams in pulp and paper mills. Application of a "zero-discharge" process is already a feasible option for the board and packaging paper industry, provided in-line treatment is a

  11. Anaerobic digestion of food waste stabilized by lime mud from papermaking process.

    Science.gov (United States)

    Zhang, Jishi; Wang, Qinqing; Zheng, Pengwei; Wang, Yusong

    2014-10-01

    The effects of lime mud from papermaking process (LMP) addition as buffer agent and inorganic nutrient on the anaerobic digestion stability of food waste (FW) were investigated under mesophilic conditions with the aim of avoiding volatile fatty acids accumulation, and inorganic elements deficiency. When LMP concentration ranged from 6.0 to 10g/L, the FW anaerobic digestion could maintain efficient and stable state. These advantages are attributed to the existence of Ca, Na, Mg, K, Fe, and alkaline substances that favor the methanogenic process. The highest CH4 yield of 272.8mL/g-VS was obtained at LMP and VS concentrations of 10.0 and 19.8g/L, respectively, with the corresponding lag-phase time of 3.84d and final pH of 8.4. The methanogens from residue digestates mainly consisted of Methanobrevibacter, coccus-type and sarcina-type methanogens with LMP addition compared to Methanobacteria in control. However, higher concentration of LMP inhibited methanogenic activities and methane production.

  12. High-strength fermentable wastewater reclamation through a sequential process of anaerobic fermentation followed by microalgae cultivation.

    Science.gov (United States)

    Qi, Wenqiang; Chen, Taojing; Wang, Liang; Wu, Minghong; Zhao, Quanyu; Wei, Wei

    2017-03-01

    In this study, the sequential process of anaerobic fermentation followed by microalgae cultivation was evaluated from both nutrient and energy recovery standpoints. The effects of different fermentation type on the biogas generation, broth metabolites' composition, algal growth and nutrients' utilization, and energy conversion efficiencies for the whole processes were discussed. When the fermentation was designed to produce hydrogen-dominating biogas, the total energy conversion efficiency (TECE) of the sequential process was higher than that of the methane fermentation one. With the production of hydrogen in anaerobic fermentation, more organic carbon metabolites were left in the broth to support better algal growth with more efficient incorporation of ammonia nitrogen. By applying the sequential process, the heat value conversion efficiency (HVCE) for the wastewater could reach 41.2%, if methane was avoided in the fermentation biogas. The removal efficiencies of organic metabolites and NH4(+)-N in the better case were 100% and 98.3%, respectively.

  13. Anaerobic electrochemical membrane bioreactor and process for wastewater treatment

    KAUST Repository

    Amy, Gary

    2015-07-09

    An anaerobic electrochemical membrane bioreactor (AnEMBR) can include a vessel into which wastewater can be introduced, an anode electrode in the vessel suitable for supporting electrochemically active microorganisms (EAB, also can be referred to as anode reducing bacteria, exoelectrogens, or electricigens) that oxidize organic compounds in the wastewater, and a cathode membrane electrode in the vessel, which is configured to pass a treated liquid through the membrane while retaining the electrochemically active microorganisms and the hydrogenotrophic methanogens (for example, the key functional microbial communities, including EAB, methanogens and possible synergistic fermenters) in the vessel. The cathode membrane electrode can be suitable for catalyzing the hydrogen evolution reaction to generate hydro en.

  14. Effects of Different States of Fe on Anaerobic Digestion:A Review

    Institute of Scientific and Technical Information of China (English)

    Wencheng Ma; Hongmei Xin; Dan Zhong; Fengyue Qian; Hongjun Han; Yuan Yuan

    2015-01-01

    Anaerobic digestion is widely used in the treatment of industrial wastewater, excess activated sludge, municipal waste, crop straw and livestock manure, with the functions of environmental protection and energy recovery. This review summarizes and evaluates the present knowledge of effects of different states of Fe ( ZVI, Fe ( II ) , Fe ( III ) ) on hydrogen and methane production in anaerobic digestion process. The potential promotion effects of iron oxides nanoparticles ( IONPs ) , especially magnetite nanoparticles on anaerobic digestion are also mentioned. Fe plays important role in transporting electron, stimulating bacterial growth and increasing hydrogen and methane production rate by promoting enzyme activity. Adding Fe with different morphologies and valence states in anaerobic digestion to increase biogas ( hydrogen and methane) production and enhance organic matter degradation simultaneously, which has attracted many scientists’ attention in recent years. Rapid progress in this area has been made over the last few years, since Fe is essential to the fermentative hydrogen and methane production, while few is known about how Fe affects the fermentative biogas production. This review is significant to maintain the stable operation of the biogas project.

  15. Combined treatment of olive mill wastewater by Fenton's reagent and anaerobic biological process.

    Science.gov (United States)

    Amor, Carlos; Lucas, Marco S; García, Juan; Dominguez, Joaquín R; De Heredia, J Beltrán; Peres, José A

    2015-01-01

    This work presents the application of Fenton's reagent process combined with anaerobic digestion to treat an olive mill wastewater (OMW). Firstly, OMW was pre-treated by chemical oxidation in a batch reactor with Fenton's reagent, using a fixed H2O2/COD ratio of 0.20, pH = 3.5 and a H2O2/Fe(2+) molar ratio of 15:1. This advanced oxidation treatment allowed reaching reductions of 17.6 and 82.5% of chemical oxygen demand (COD) and total polyphenols (TP), respectively. Secondly, OMW treatment by anaerobic digestion was performed using previously adapted microorganisms immobilized in Sepiolite. These biological tests were carried out varying the substrate concentration supplied to the reactor and COD conversions from 52 to 74% were obtained. Afterwards, Fenton's reagent followed by anaerobic digestion was applied to OMW treatment. This combined process presented a significant improvement on organic load removal, reaching COD degradations from 64 to 88%. Beyond the pollutant load removal, it was also monitored the yield of methane generated throughout anaerobic experiments. The methane produced ranged from 281 cm(3) to 322 cm(3) of CH4/g COD removed. Additionally, a methane generation kinetic study was performed using the Monod Model. The application of this model allowed observing a kinetic constant increase of the combined process (kFN = 0.036 h(-1)) when compared to the single anaerobic process (kF = 0.017 h(-1)).

  16. Monitoring of anaerobic digestion processes: A review perspective

    DEFF Research Database (Denmark)

    Madsen, Michael; Holm-Nielsen, Jens Bo; Esbensen, Kim

    2011-01-01

    to a new level of reliability and effectiveness. It is shown, how proper involvement of process sampling understanding, Theory of Sampling (TOS), constitutes a critical success factor. We survey the more recent trends within the field of AD monitoring and the powerful PAT/TOS/chemometrics application...

  17. The effect of outside conditions on anaerobic ammonia oxidation reaction

    Institute of Scientific and Technical Information of China (English)

    YANG Min; WANG Shu-bo

    2016-01-01

    Organic carbon, inorganic carbon, temperature, pH and ORP are all to have a certain influence on the anaerobic ammonia oxidation reaction. We can draw some conclusions on the optimum conditions of anaerobic ammonia oxidation reaction. The optimum temperature of the anaerobic ammonia oxidation reaction is 30-35℃. And the optimum pH of the anaerobic ammonia reaction is 7.5-8.3. The presence of organic matters can affect the anaerobic ammonia reaction, and different organic matters have different influence on it. The concentration of the inorganic carbon also exist great influence on the reaction. High inorganic carbon concentration also can inhibit anaerobic ammonia oxidation reaction.

  18. The Effect of Iron Salt on Anaerobic Digestion and Phosphate Release to Sludge Liquor

    Directory of Open Access Journals (Sweden)

    Svetlana Ofverstrom

    2011-12-01

    Full Text Available Iron salts are used at wastewater treatment plants (WWTPs for several reasons: for removing chemical phosphorus, preventing from struvite formation and reducing the content of hydrogen sulfide (H2S in biogas. Anaerobic digestion is a common scheme for sludge treatment due to producing biogas that could be used as biofuel. Laboratory analysis has been carried out using anaerobic digestion model W8 (Armfield Ltd, UK to investigate any possible effect of adding FeCl3 on the anaerobic digestion of primary sludge (PS and waste activated sludge (WAS mixture as well as on releasing phosphates to digested sludge liquor. The obtained results showed that FeCl3 negatively impacted the anaerobic digestion process by reducing the volume of produced biogas. Fe-dosed sludge (max produced 30% less biogas. Biogas production from un-dosed and Fe-dosed sludge (min was similar to the average of 1.20 L/gVSfed. Biogas composition was not measured during the conducted experiments. Phosphorus content in sludge liquor increased at an average of 38% when digesting sludge without ferric chloride dosing. On the contrary, phosphate content in sludge liquor from digested Fe-dosed sludge decreased by approx. 80%.

  19. How to use molecular biology tools for the study of the anaerobic digestion process?

    NARCIS (Netherlands)

    Cabezas, Angela; Araujo, de Juliana Calabria; Callejas, Cecilia; Galès, Amandine; Hamelin, Jérôme; Marone, Antonella; Machado de Sousa, Diana; Trably, Eric; Etchebehere, Claudia

    2015-01-01

    Anaerobic digestion is used with success for the treatment of solid waste, urban and industrial effluents with a concomitant energy production. The process is robust and stable, but the complexity of the microbial community involved in the process is not yet fully comprehensive. Nowadays, the stu

  20. Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Miyahara, Michiko; Miyahara, Makoto [National Inst. of Health Sciences, Tokyo (Japan)

    2002-10-01

    An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the lethal dose 10% (D{sub 10}) value of B. cereus at 4 deg C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 deg C. The gamma irradiation of the bacteria without incubation at 4 deg C before irradiation was more effective than that of the bacteria with incubation overnight at 4 deg C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 deg C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. (author)

  1. Process control of anaerobic biogas fermentation. Process control systems based on microcontroller based computational intelligence; Prozessfuehrung der anaerobe Biogasfermentation. Prozessfuehrungssysteme auf Basis mikrocontrollerbasierter Computational Intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, K.D. [Hochschule Harz, Wernigerode (Germany); Patzwahl, S.; Nacke, T.

    2005-07-01

    This article presents three system variants for the process control and monitoring of anaerobic biogas fermentation. All three systems were created using a self-developed software called ''EmCoSoft'' and a design process and were tested as microcontroller-based solutions. Strategies of computational intelligence (including Fuzzy Logic and Artificial Neuronal Networks) were considered most suitable for generating system core algorithms and were put to use. Experiments for generating process data and test sequences for each of the system variants were performed on well-equipped laboratory biogas plants.

  2. Characteristics of hydrogen and methane production from cornstalks by an augmented two- or three-stage anaerobic fermentation process.

    Science.gov (United States)

    Lu, Yuan; Lai, Qiheng; Zhang, Chong; Zhao, Hongxin; Ma, Kun; Zhao, Xuebing; Chen, Hongzhang; Liu, Dehua; Xing, Xin-Hui

    2009-06-01

    This paper presents the co-production of hydrogen and methane from cornstalks by a two- or three-stage anaerobic fermentation process augmented with effective artificial microbial community. Two-stage fermentation by using the anaerobic sludge and DGGE analysis showed that effective and stable strains should be introduced into the system. We introduced Enterobacter aerogens or Clostridium paraputrificum into the hydrogen stage, and C. paraputrificum was proven to be more effective. In the three-stage process consisting of the improved hydrolysis, hydrogen and methane production stages, the highest soluble sugars (0.482 kg/kg cornstalks) were obtained after the introduction of Clostridium thermocellum in the hydrolysis stage, under the thermophilic (55 degrees C) and acidic (pH 5.0) conditions. Hydrolysates from 1 kg of cornstalks could produce 2.61 mol (63.7 l) hydrogen by augmentation with C. paraputrificum and 4.69 mol (114.6 l) methane by anaerobic granular sludge, corresponding to 54.1% energy recovery.

  3. Anaerobic wastewater treatment in the food processing industry: two case studies

    Energy Technology Data Exchange (ETDEWEB)

    Campos, J.R.; Foresti, E.; Camacho, R.D.P.

    1986-01-01

    This article relates two experiments with wastewater treatment in the food processing industry. One of them refers to the use of an anaerobic filter (meat processing industry) and the other to the use of an upflow anaerobic sludge blanket reactor-UASB (vegetable and fruit processing industry). In the first case, the study describes the performance of an anaerobic filter which has been working for 6 years and provides COD removal efficiency (including primary treatment) equal or better than 80% with an organic loading of 1.4 kg of COD/cubic m/day. The reactor has a bed of broken stones with size of 0.75 m having a medium hydraulic retention time of 13 hours. Discharges of accumulated sludge in a false bottom below the filter are made at intervals of 2 or 3 months. In the second case, the study describes the performance of an upflow anaerobic sludge blanket reactor (88 cubic m) during 255 days of operation including the adaptation phase or startup. This reactor receives wastewater from vegetable and fruit processing including tomato, corn, guava and peach. At the end of each operational phase studied, the COD removal efficiency was about 80%. In the last phase (7.5 hours hydraulic retention time), the organic loading was 1.4 kg of COD/cubic m/day and the hydraulic loading was 3.2 cubic m/cubic m/day. (Refs. 11).

  4. Biohydrogen Production from Cheese Processing Wastewater by Anaerobic Fermentation Using Mixed Microbial Communities

    Science.gov (United States)

    Hydrogen (H2) production from simulated cheese processing wastewater via anaerobic fermentation was conducted using mixed microbial communities under mesophilic conditions. In batch H2 fermentation experiments H2 yields of 8 and 10 mM/g-COD fed were achieved at food-to-microorganism (F/M) ratios of ...

  5. Effect of increasing total solids contents on anaerobic digestion of food waste under mesophilic conditions: performance and microbial characteristics analysis.

    Directory of Open Access Journals (Sweden)

    Jing Yi

    Full Text Available The total solids content of feedstocks affects the performances of anaerobic digestion and the change of total solids content will lead the change of microbial morphology in systems. In order to increase the efficiency of anaerobic digestion, it is necessary to understand the role of the total solids content on the behavior of the microbial communities involved in anaerobic digestion of organic matter from wet to dry technology. The performances of mesophilic anaerobic digestion of food waste with different total solids contents from 5% to 20% were compared and the microbial communities in reactors were investigated using 454 pyrosequencing technology. Three stable anaerobic digestion processes were achieved for food waste biodegradation and methane generation. Better performances mainly including volatile solids reduction and methane yield were obtained in the reactors with higher total solids content. Pyrosequencing results revealed significant shifts in bacterial community with increasing total solids contents. The proportion of phylum Chloroflexi decreased obviously with increasing total solids contents while other functional bacteria showed increasing trend. Methanosarcina absolutely dominated in archaeal communities in three reactors and the relative abundance of this group showed increasing trend with increasing total solids contents. These results revealed the effects of the total solids content on the performance parameters and the behavior of the microbial communities involved in the anaerobic digestion of food waste from wet to dry technologies.

  6. Effect of oxygen on the microbial activities of thermophilic anaerobic biomass.

    Science.gov (United States)

    Pedizzi, C; Regueiro, L; Rodriguez-Verde, I; Lema, J M; Carballa, M

    2016-07-01

    Low oxygen levels (μgO2L(-1)) in anaerobic reactors are quite common and no relevant consequences are expected. On the contrary, higher concentrations could affect the process. This work aimed to study the influence of oxygen (4.3 and 8.8mgO2L(-1), respectively) on the different microbial activities (hydrolytic, acidogenic and methanogenic) of thermophilic anaerobic biomass and on the methanogenic community structure. Batch tests in presence of oxygen were conducted using specific substrates for each biological activity and a blank (with minimum oxygen) was included. No effect of oxygen was observed on the hydrolytic and acidogenic activities. In contrast, the methane production rate decreased by 40% in all oxygenated batches and the development of active archaeal community was slower in presence of 8.8mgO2L(-1). However, despite this sensitivity of methanogens to oxygen at saturation levels, the inhibition was reversible.

  7. Two-stage anaerobic and post-aerobic mesophilic digestion of sewage sludge: Analysis of process performance and hygienization potential.

    Science.gov (United States)

    Tomei, M Concetta; Mosca Angelucci, Domenica; Levantesi, Caterina

    2016-03-01

    Sequential anaerobic-aerobic digestion has been demonstrated to be effective for enhanced sludge stabilization, in terms of increased solid reduction and improvement of sludge dewaterability. In this study, we propose a modified version of the sequential anaerobic-aerobic digestion process by operating the aerobic step under mesophilic conditions (T=37 °C), in order to improve the aerobic degradation kinetics of soluble and particulate chemical oxygen demand (COD). Process performance has been assessed in terms of "classical parameters" such as volatile solids (VS) removal, biogas production, COD removal, nitrogen species, and polysaccharide and protein fate. The aerobic step was operated under intermittent aeration to achieve nitrogen removal. Aerobic mesophilic conditions consistently increased VS removal, providing 32% additional removal vs. 20% at 20 °C. Similar results were obtained for nitrogen removal, increasing from 64% up to 99% at the higher temperature. Improved sludge dewaterability was also observed with a capillary suction time decrease of ~50% during the mesophilic aerobic step. This finding may be attributable to the decreased protein content in the aerobic digested sludge. The post-aerobic digestion exerted a positive effect on the reduction of microbial indicators while no consistent improvement of hygienization related to the increased temperature was observed. The techno-economic analysis of the proposed digestion layout showed a net cost saving for sludge disposal estimated in the range of 28-35% in comparison to the single-phase anaerobic digestion.

  8. Effects of microbial inhibitors on anaerobic degradation of DDT

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.S.; Chiu, T.C.; Yen, J.H. [National Taiwan Univ., Taipei (Taiwan)

    2004-09-15

    Chlorinated insecticide DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] was extensively used for controlling pests in the agricultural field and human-being living environments in the past several decades. Due to the chemical stability, DDT was extremely persistent and recalcitrant in soils and sediments and it was banned by nations. Microorganisms usually play important roles in reducing organochlorine compounds in the environments. Under low-oxygen conditions, microbial dechlorination is thought as the onset of highly chlorinated compounds. Methanogenic and sulfate-reducing bacteria participate in microbial dechlorination under anaerobic condition has been reported. In this study, a mixed anaerobic culture enabling to dechlorinate DDT was obtained from river sediment in Taiwan. In order to understand the effect of these microorganisms on DDT dechlorination, microbial inhibitors BESA (2-bromoethanesulfonate) and molybdate, for inhibiting methanogenic and sulfate-reducing bacteria, respectively, were chosen to investigate the interaction between specific microbial communities and their degradation activities. Besides, a molecular technique, denaturing gradient gel electrophoresis (DGGE), based on analyzing the 16S rDNA of bacteria, was used for monitoring the bacterial community structure in this study.

  9. Thermophilic aerobic post treatment of anaerobically pretreated paper process water

    OpenAIRE

    Vogelaar, J.C.T.

    2002-01-01

    Thermophilic waste- or process water treatment increases in importance as industries shift from end-of-pipe treatment towards integrated process water treatment. The need for process water treatment becomes evident as the levels of pollutants in industrial water circuits need to be controlled whereas the intake of fresh water generally diminishes. In the paper and board industry, high process water temperatures prevail and thus water treatment needs to take place under thermophilic conditions...

  10. Thermophilic aerobic post treatment of anaerobically pretreated paper process water

    NARCIS (Netherlands)

    Vogelaar, J.C.T.

    2002-01-01

    Thermophilic waste- or process water treatment increases in importance as industries shift from end-of-pipe treatment towards integrated process water treatment. The need for process water treatment becomes evident as the levels of pollutants in industrial water circuits need to be co

  11. Seasonal and spatial variation in soil chemistry and anaerobic processes in an Arctic ecosystem

    Science.gov (United States)

    Lipson, D.; Mauritz, M.; Bozzolo, F.; Raab, T. K.; Santos, M. J.; Friedman, E. F.; Rosenbaum, M.; Angenent, L.

    2009-12-01

    Drained thaw lake basins (DTLB) are the dominant landform in the Arctic coastal plain near Barrow, Alaska. Our previous work in a DTLB showed that Fe(III) and humic substances are important electron acceptors in anaerobic respiration, and play a significant role in the C cycle of these organic-rich soils. In the current study, we investigated seasonal and spatial patterns of availability of electron acceptors and labile substrate, redox conditions and microbial activity. Landscapes within DTLB contain complex, fine-scale topography arising from ice wedge polygons, which produce raised and lowered areas. One goal of our study was to determine the effects of microtopographic variation on the potential for Fe(III) reduction and other anaerobic processes. Additionally, the soil in the study site has a complex vertical structure, with an organic peat layer overlying a mineral layer, overlying permafrost. We described variations in soil chemistry across depth profiles into the permafrost. Finally, we installed an integrated electrode/potentiostat system to electrochemically monitor microbial activity in the soil. Topographically low areas differed from high areas in most of the measured variables: low areas had lower oxidation-reduction potential, higher pH and electrical conductivity. Soil pore water from low areas had higher concentrations of Fe(III), Fe(II), dissolved organic C (DOC), and aromaticity (UV absorbance at 260nm, “A260”). Low areas also had higher concentrations of dissolve CO2 and CH4 in soil pore water. Laboratory incubations of soil showed a trend toward higher potentials for Fe(III) reduction in topographically low areas. Clearly, ice wedge-induced microtopography exerts a strong control on microbial processes in this DTLB landscape, with increased anaerobic activity occurring in the wetter, depressed areas. Soil water extracted from 5-15 cm depth had higher concentrations of Fe(III), Fe(II), A260, and DOC compared to soil water sampled from 0-5cm

  12. Performance evaluation of a two-phase anaerobic digestion process of synthetic domestic wastewater at ambient temperature.

    Science.gov (United States)

    Guerrero, L; Montalvo, S; Coronado, E; Chamy, R; Poirrier, P; Crutchik, D; Sánchez, E; De La Rubia, M A; Borja, R

    2009-06-01

    A two-phase anaerobic digestion process of synthetic domestic wastewater was studied at ambient temperature in mild to cold climates. The hydrolytic stage was carried out in a continuous stirred tank reactor with an effective volume of 1.2 L. The hydrolytic reactor operated at hydraulic retention times (HRTs) in the range of 1.3 to 2.7 h, which allowed for optimum HRT to be obtained in order to achieve a maximum amount of soluble COD. For the methanogenic stage, an up-flow anaerobic filter with a volume of 1.35 L and corrugated plastic rings as biomass immobilization support were used. During the investigation, the ambient temperature ranged between 21 degrees C and 24 degrees C. Synthetic domestic wastewater with a COD of 700 mg/L was used as substrate. The study was performed at total organic loading rates (OLR(T)) of 2.0-4.3 g COD/L. d, with a global HRT (including both hydrolytic and methanogenic stages) of 2.8-5.8 hours. A maximum percentage of organic matter removed of 88% was achieved at a global HRT of 5.8 hours. Under these operating conditions, the production of biogas was 97% higher than that obtained in the one-phase anaerobic digestion process. Additionally, the kinetics involved in the hydrolytic stage was determined using the Contois kinetic model, which adequately predicted the experimental results.

  13. Dry-thermophilic anaerobic digestion of simulated organic fraction of municipal solid waste: process modeling.

    Science.gov (United States)

    Fdez-Güelfo, L A; Álvarez-Gallego, C; Sales Márquez, D; Romero García, L I

    2011-01-01

    Solid retention time (SRT) is a very important operational variable in continuous and semicontinuous waste treatment processes since the organic matter removal efficiency--expressed in terms of percentage of Dissolved Organic Carbon (% DOC) or Volatile Solids (% VS) removed--and the biogas or methane production are closely related with the SRT imposed. Optimum SRT is depending on the waste characteristics and the microorganisms involved in the process and, hence, it should be determined specifically in each case. In this work a series of experiments were carried out to determine the effect of SRT, from 40 to 8 days, on the performance of the dry (30% Total Solids) thermophilic (55°C) anaerobic digestion of organic fraction of Municipal Solid Wastes (OFMSW) operating at semicontinuous regime of feeding. The experimental results show than 15days is the optimum SRT (the best between all proved) for this process. Besides, data of organic matter concentration and methane production versus SRT have been used to obtain the kinetic parameters of the kinetic model of Romero García (1991): the maximum specific growth rate of the microorganisms (μmax=0.580 days(-1)) and the fraction of substrate non-biodegradable (α=0.268).

  14. Enhanced Versus Conventional Sludge Anaerobic Processes: Performances and Techno-Economic Assessment.

    Science.gov (United States)

    Gianico, Andrea; Bertanza, Giorgio; Braguglia, Camilla M; Canato, Matteo; Gallipoli, Agata; Laera, Giuseppe; Levantesi, Caterina; Mininni, Giuseppe

    2016-05-01

    Sewage sludge processing is a key issue in water resource recovery facilities due to the inefficacy of conventional treatments to produce high quality biosolids to be safely used in agriculture. Under this framework, the performances of several enhanced stabilization processes, namely ultrasound-pretreated Mesophilic Anaerobic Digestion (US+MAD), thermophilic anaerobic digestion (TAD), thermal-pretreated TAD (TH+TAD) and ultrasound-pretreated inverse Temperature Phased Anaerobic Digestion (US+iTPAD) have been investigated. Such enhanced processes resulted in higher biogas yields and higher destruction of pathogens with respect to conventional MAD process, thus suggesting their feasibility in full-scale implementation perspectives. A procedure for technical-economic comparison of new sludge processing lines against conventional ones (benchmarking) was developed, based on the definition of technical issues (e.g. reliability, complexity, etc.) which are rated for each situation. Moreover, capital and operating costs were estimated. The enhanced processes analyzed in this work showed some potentially critical items, mainly related to energy balance and reagent consumption.

  15. Assessment of anaerobic bacterial diversity and its effects on anaerobic system stability and the occurrence of antibiotic resistance genes.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2016-05-01

    This study evaluated the link between anaerobic bacterial diversity and, the biodegradation of antibiotic combinations and assessed how amending antibiotic combination and increasing concentration of antibiotics in a stepwise fashion influences the development of resistance genes in anaerobic reactors. The biodegradation, sorption and occurrence of the known antibiotic resistance genes (ARGs) of erythromycin and tetracycline were investigated using the processes of UV-HPLC and qPCR analysis respectively. Ion Torrent sequencing was used to detect microbial community changes in response to the addition of antibiotics. The overall results indicated that changes in the structure of a microbial community lead to changes in biodegradation capacity, sorption of antibiotics combinations and occurrence of ARGs. The enhanced biodegradation efficiency appeared to generate variations in the structure of the bacterial community. The results suggested that controlling the ultimate Gram-negative bacterial community, especially Acinetobacter-related populations, may promote the successful biodegradation of antibiotic combinations and reduce the occurrence of ARGs.

  16. Effects of disinfectants and antibiotics on the anaerobic digestion of piggery waste

    Energy Technology Data Exchange (ETDEWEB)

    Poels, J.; Van Assche, P.; Verstraete, W.

    1984-01-01

    The effects of disinfectants and antibiotics on the anaerobic digestion of piggery waste were investigated. The disinfectants Tego 51, Dettol, NaOCl and Creolin, and the antibiotics, chlortetracyclin, tylosin, erythromycin, chloramphenicol, bacitracin and virginiamycin were tested at different concentrations. At concentrations normally used in practice, no inhibitory effect on methanisation process was detected. However, higher concentrations of the antimicrobial agents, Dettol, Creolin, bacitracin and virginiamycin, markedly inhibited biogas production. In order to minimize possible digester failures, farmers are advised to respect the normal recommended dose and to use low-toxicity antimicrobial agents. (Refs. 8).

  17. Saponification pretreatment and solids recirculation as a new anaerobic process for the treatment of slaughterhouse waste.

    Science.gov (United States)

    Affes, R; Palatsi, J; Flotats, X; Carrère, H; Steyer, J P; Battimelli, A

    2013-03-01

    Different configurations of anaerobic process, adapted to the treatment of solid slaughterhouse fatty waste, were proposed and evaluated in this study. The tested configurations are based on the combination of anaerobic digestion with/without waste saponification pretreatment (70 °C during 60 min) and with/without recirculation of the digestate solid fraction (ratio=20% w/w). After an acclimation period of substrate pulses-feeding cycles, the reactors were operated in a semi-continuous feeding mode, increasing organic loading rates along experimental time. The degradation of the raw substrate was shown to be the bottleneck of the whole process, obtaining the best performance and process yields in the reactor equipped with waste pretreatment and solids recirculation. Saponification promoted the emulsification and bioavailability of solid fatty residues, while recirculation of solids minimized the substrate/biomass wash-out and induced microbial adaptation to the treatment of fatty substrates.

  18. Feasibility tests for treating shampoo and hair colorant wastewaters using anaerobic processes.

    Science.gov (United States)

    Ahammad, Shaikh Z; Yakubu, A; Dolfing, J; Mota, C; Graham, D W

    2012-01-01

    Wastes from the personal care product (PCP) industry are often high in biodegradable carbon, which makes them amenable to aerobic biological treatment, although process costs are usually high due to aeration inefficiencies, high electricity demand and production of large amounts of sludge. As such, anaerobic treatment technologies are being considered to lower net energy costs by reducing air use and increasing methane production. To assess the amenability of PCP wastes to anaerobic treatment, methane yields and rates were quantified in different anaerobic reactors treating typical PCP wastes, including wastes from shampoo and hair colorant products. Overall, shampoo wastes were more amenable to methanogenesis with almost double the methane yields compared with colour wastes. To assess relevant microbial guilds, qPCR was performed on reactor biomass samples. Methanosaetaceae abundances were always significantly higher than Methanosarcinaceae and Methanomicrobiales abundances (P shampoo wastes, differences cannot be explained by relative microbial abundances and probably result from the presence of inhibiting compounds in hair colorants (e.g., oxidants) at higher levels. Results showed that anaerobic technologies have great potential for treating PCP wastes, but additional work is needed to establish the basis of elevated methane yields and inhibition, especially when colorant wastes are present.

  19. Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

    Science.gov (United States)

    Grübel, Klaudiusz; Suschka, Jan

    2015-05-01

    The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

  20. Simulation of aerobic and anaerobic biodegradation processes at a crude oil spill site

    Science.gov (United States)

    Essaid, Hedeff I.; Bekins, Barbara A.; Godsy, E. Michael; Warren, Ean; Baedecker, Mary Jo; Cozzarelli, Isabelle M.

    1995-01-01

    A two-dimensional, multispecies reactive solute transport model with sequential aerobic and anaerobic degradation processes was developed and tested. The model was used to study the field-scale solute transport and degradation processes at the Bemidji, Minnesota, crude oil spill site. The simulations included the biodegradation of volatile and nonvolatile fractions of dissolved organic carbon by aerobic processes, manganese and iron reduction, and methanogenesis. Model parameter estimates were constrained by published Monod kinetic parameters, theoretical yield estimates, and field biomass measurements. Despite the considerable uncertainty in the model parameter estimates, results of simulations reproduced the general features of the observed groundwater plume and the measured bacterial concentrations. In the simulation, 46% of the total dissolved organic carbon (TDOC) introduced into the aquifer was degraded. Aerobic degradation accounted for 40% of the TDOC degraded. Anaerobic processes accounted for the remaining 60% of degradation of TDOC: 5% by Mn reduction, 19% by Fe reduction, and 36% by methanogenesis. Thus anaerobic processes account for more than half of the removal of DOC at this site.

  1. Effects of anaerobic digestion and aerobic treatment on gaseous emissions from dairy manure storages

    Science.gov (United States)

    Effects of anaerobic digestion and aerobic treatment on the reduction of gaseous emissions from dairy manure storages were evaluated in this study. Screened dairy manure containing 3.5% volatile solids (VS) was either anaerobically digested or aerobically treated prior to storage in air-tight vessel...

  2. The Effect of Enzyme Addition on Anaerobic Digestion of Jose Tall Wheat Grass

    Science.gov (United States)

    The effects of the addition of enzyme products containing cellulase, hemicellulase, and Beta-glucosidase to anaerobic digestion systems were studied. Anaerobic digestion tests were performed using batch reactors operated at 35°C. The application of enzyme products in three digestion configurations w...

  3. Effect of ferrihydrite biomineralization on methanogenesis in an anaerobic incubation from paddy soil

    Science.gov (United States)

    Zhuang, Li; Xu, Jielong; Tang, Jia; Zhou, Shungui

    2015-05-01

    Microbial reduction of Fe(III) can be one of the major factors controlling methane production from anaerobic sedimentary environments, such as paddy soils and wetlands. Although secondary iron mineralization following Fe(III) reduction is a process that occurs naturally over time, it has not yet been considered in methanogenic systems. This study performed a long-term anaerobic incubation of a paddy soil and ferrihydrite-supplemented soil cultures to investigate methanogenesis during ferrihydrite biomineralization. The results revealed that the long-term effect of ferrihydrite on methanogenesis may be enhancement rather than suppression documented in previous studies. During initial microbial ferrihydrite reduction, methanogenesis was suppressed; however, the secondary minerals of magnetite formation was simultaneous with facilitated methanogenesis in terms of average methane production rate and acetate utilization rate. In the phase of magnetite formation, microbial community analysis revealed a strong stimulation of the bacterial Geobacter, Bacillus, and Sedimentibacter and the archaeal Methanosarcina in the ferrihydrite-supplemented cultures. Direct electric syntrophy between Geobacter and Methanosarcina via conductive magnetite is the plausible mechanism for methanogenesis acceleration along with magnetite formation. Our data suggested that a change in iron mineralogy might affect the conversion of anaerobic organic matter to methane and might provide a fresh perspective on the mitigation of methane emissions from paddy soils by ferric iron fertilization.

  4. Solid-state anaerobic co-digestion of hay and soybean processing waste for biogas production.

    Science.gov (United States)

    Zhu, Jiying; Zheng, Yi; Xu, Fuqing; Li, Yebo

    2014-02-01

    Co-digestion of soybean processing waste (SPW) and hay in solid-state anaerobic digestion (SS-AD) for biogas production was investigated. Effects of the SPW to hay ratio, feedstock to effluent (inoculum) ratio, premixing of effluent with feedstock, and leachate recirculation on biogas production via SS-AD were studied. The highest methane yield of 258 L/kg VS was obtained with a SPW/hay ratio of 75:25 and feedstock/effluent (F/E) ratio of 3, which was 148% and 50% higher than that of 100% SPW and 100% hay, respectively. Increasing the F/E ratio from 1 to 5 decreased methane yield, however the highest volumetric methane yield (16.2L/L reactor) was obtained at an F/E of 3. There was no significant difference in methane yields between premixing 50% and 100% of the effluent. Leachate recirculation significantly accelerated the SS-AD start-up process when effluent was not completely premixed.

  5. Hyperspectral imaging techniques applied to the monitoring of wine waste anaerobic digestion process

    Science.gov (United States)

    Serranti, Silvia; Fabbri, Andrea; Bonifazi, Giuseppe

    2012-11-01

    An anaerobic digestion process, finalized to biogas production, is characterized by different steps involving the variation of some chemical and physical parameters related to the presence of specific biomasses as: pH, chemical oxygen demand (COD), volatile solids, nitrate (NO3-) and phosphate (PO3-). A correct process characterization requires a periodical sampling of the organic mixture in the reactor and a further analysis of the samples by traditional chemical-physical methods. Such an approach is discontinuous, time-consuming and expensive. A new analytical approach based on hyperspectral imaging in the NIR field (1000 to 1700 nm) is investigated and critically evaluated, with reference to the monitoring of wine waste anaerobic digestion process. The application of the proposed technique was addressed to identify and demonstrate the correlation existing, in terms of quality and reliability of the results, between "classical" chemical-physical parameters and spectral features of the digestate samples. Good results were obtained, ranging from a R2=0.68 and a RMSECV=12.83 mg/l for nitrate to a R2=0.90 and a RMSECV=5495.16 mg O2/l for COD. The proposed approach seems very useful in setting up innovative control strategies allowing for full, continuous control of the anaerobic digestion process.

  6. Kinetic analysis of anaerobic phosphorus release during biological phosphorus removal process

    Institute of Scientific and Technical Information of China (English)

    DOU Junfeng; LUO Guyuan; LIU Xiang

    2007-01-01

    Enhanced biological phosphorus removal(EBPR)is a commonly used and sustainable method for phosphorus removal from wastewater.Poly-β-hydroxybutyrate(PHB),polyphosphate,and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation organisms.The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release,which is very important for controlling the performance of EBPR.To obtain the mechanism and kinetic character of anaerobic phosphorus release,a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit of the biological phosphorus removal system in this study.The results showed that the volatile suspended solid(vss)had an increasing trend,while the mixed liquid suspended sludge(MLSS)and ashes were reduced during the anaerobic phosphorus release process.The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms is exhausted.Under the condition of lower initial HAc-COD,HAc became the limiting factor after some time for anaerobic HAc uptake.Under the condition of higher initial HAc-COD,HAc uptake was stopped because of the depletion of glycogen in the microorganisms.The mean ratio of △ρP/△ρPHB,△ρGLY/△ρPHB,△ρP/△COD,and △ρPHB/△COD was 0.48,0.50,0.44.and 0.92.respectively,which was nearly the same as the theoretical value.The calibrated kinetic parameters of the HAc-uptake and phosphorus-release model were evaluated as Kgly was 0.005,and KCOD was 3 mg/L.An apparently linear correlation was observed between the ratio of △ρP/△COD and pH of the solution,and the equation between them was obtained in this study.

  7. Ammonia removal in food waste anaerobic digestion using a side-stream stripping process.

    Science.gov (United States)

    Serna-Maza, A; Heaven, S; Banks, C J

    2014-01-01

    Three 35-L anaerobic digesters fed on source segregated food waste were coupled to side-stream ammonia stripping columns and operated semi-continuously over 300 days, with results in terms of performance and stability compared to those of a control digester without stripping. Biogas was used as the stripping medium, and the columns were operated under different conditions of temperature (55, 70, 85 °C), pH (unadjusted and pH 10), and RT (2-5 days). To reduce digester TAN concentrations to a useful level a high temperature (≥70 °C) and a pH of 10 were needed; under these conditions 48% of the TAN was removed over a 138-day period without any detrimental effects on digester performance. Other effects of the stripping process were an overall reduction in digestate organic nitrogen-containing fraction compared to the control and a recovery in the acetoclastic pathway when TAN concentration was 1770±20 mg kg(-1).

  8. Kinetic evaluation and process performance of an upflow anaerobic filter reactor degrading terephthalic acid.

    Science.gov (United States)

    Davutluoglu, Orkun I; Seckin, Galip

    2014-01-01

    The anaerobic degradation of terephthalic acid (TA) as the sole organic carbon source was studied in an upflow anaerobic filter (UAF) reactor. The reactor was seeded with biomass obtained from a full-scale upflow anaerobic sludge bed (UASB) reactor and was used to treat wastewater from a petrochemical facility producing dimethyl terephthalate. The UAF reactor was operated for 252 d with a constant hydraulic retention time of 24 h, and the organic loading rate (OLR) was gradually increased from 1 to 10 g-chemical oxygen demand (COD)/L d. After a lag period of approximately 40 d, the COD removal efficiency increased exponentially and high removal rate values (≈90%) were obtained, except for at highest OLR (10 g-COD/L d). The high removal rates and the robustness of the reactor performance could be attributed to the formation of biofilm as well as granular sludge. The methane production rates (0.22 to 2.15 L/d) correlated well with the removed OLRs (0.3 to 6.8 g-COD/L d) during the various phases of treatment, indicating that the main mechanism of TA degradation occurs via methanogenic reactions. The average methane content of the produced biogas was 70.3%. The modified Stover-Kincannon model was found to be applicable for the anaerobic degradation of TA in UAFs (Umax = 64.5, KB = 69.1 g-COD/L d and Ymax = 0.27 L-CH4/g-CODremoved). These results suggest that UAF reactors are among the most effective reactor configurations for the anaerobic degradation of TA.

  9. A novel process simulation model (PSM) for anaerobic digestion using Aspen Plus.

    Science.gov (United States)

    Rajendran, Karthik; Kankanala, Harshavardhan R; Lundin, Magnus; Taherzadeh, Mohammad J

    2014-09-01

    A novel process simulation model (PSM) was developed for biogas production in anaerobic digesters using Aspen Plus®. The PSM is a library model of anaerobic digestion, which predicts the biogas production from any substrate at any given process condition. A total of 46 reactions were used in the model, which include inhibitions, rate-kinetics, pH, ammonia, volume, loading rate, and retention time. The hydrolysis reactions were based on the extent of the reaction, while the acidogenic, acetogenic, and methanogenic reactions were based on the kinetics. The PSM was validated against a variety of lab and industrial data on anaerobic digestion. The P-value after statistical analysis was found to be 0.701, which showed that there was no significant difference between discrete validations and processing conditions. The sensitivity analysis for a ±10% change in composition of substrate and extent of reaction results in 5.285% higher value than the experimental value. The model is available at http://hdl.handle.net/2320/12358 (Rajendran et al., 2013b).

  10. Research on Anaerobic Digestion: Optimization and Scalability of Mixed High-strength Food Processing Wastes for Renewable Biogas Energy

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Zhongtang [The Ohio State Univ., Columbus, OH (United States); Hitzhusen, Fredrick [The Ohio State Univ., Columbus, OH (United States)

    2012-12-27

    This research project developed and improved anaerobic digestion technologies, created a comprehensive Inventory of Ohio Biomass and a database of microorganisms of anaerobic digesters, and advanced knowledge and understanding of the underpinning microbiology of the anaerobic digestion process. The results and finding of this research project may be useful for future development and implementation of anaerobic digesters, especially at livestock farms. Policy makers and investors may also find the information on the biomass availability in Ohio and valuation of energy projects useful in policy making and making of investment decisions. The public may benefit from the information on biogas as an energy source and the potential impact of anaerobic digester projects on their neighborhoods.

  11. Anaerobic digestion of Jatropha curcas L. press cake and effects of an iron-additive.

    Science.gov (United States)

    Schmidt, Thomas

    2011-11-01

    Oil production from Jatropha curcas L. seeds generates large amounts of Jatropha press cake (JPC) which can be utilized as a substrate for biogas production. The objective of this work was to investigate anaerobic mono-digestion of JPC and the effects of an iron additive (IA) on gas quality and process stability during the increase of the organic loading rate (OLR). With the increase of the OLR from 1.3 to 3.2 g(VS) L(-1) day(-1), the biogas yield in the reference reactor (RR) without IA decreased from 512 to 194 L(N) kg(VS) (-1) and the CH₄ concentration decreased from 69.3 to 44.4%. In the iron additive reactor (IAR), the biogas yield decreased from 530 to 462 L(N) kg(VS) (-1) and the CH₄ concentration decreased from 69.4 to 61.1%. The H₂S concentration in the biogas was reduced by addition of the IA to values below 258 ppm in the IAR while H₂S concentration in the RR increased and exceeded the detection limit of 5000 ppm. The acid capacity (AC) in the RR increased to more than 20 g L(-1), indicating an accumulation of organic acids caused by process instability. AC values in the IAR remained stable at values below 5 g L(-1). The results demonstrate that JPC can be used as sole substrate for anaerobic digestion up to an OLR of 2.4 g(VS) l(-1) day(-1). The addition of IA has effectively decreased the H(2)S content in the biogas and has improved the stability of the anaerobic process and the biogas quality.

  12. The effect of cyclic anaerobic-aerobic conditions on biodegradation of azo dyes.

    Science.gov (United States)

    Yaşar, Semra; Cirik, Kevser; Cinar, Ozer

    2012-03-01

    The effect of cyclic anaerobic-aerobic conditions on the biodegradative capability of the mixed microbial culture for the azo dye Remazol Brilliant Violet 5R (RBV-5R) was investigated in the sequencing batch reactor (SBR) fed with a synthetic textile wastewater. The SBR had a 12-h cycle time with anaerobic-aerobic periods of 3/9, 6/6 and 9/3 h. General SBR performance was assessed by measurement of catabolic enzymes (catechol 2,3-dioxygenase, azo reductase), chemical oxygen demand (COD), color and amount of aromatic amines. In this study, under steady-state conditions, the anaerobic period of the cyclic SBR was found to allow the reductive decolorization of azo dye. Longer anaerobic periods resulted in higher color removal efficiencies, approximately 71% for the 3-h, 87% for 6-h and 92% for the 9-h duration. Total COD removal efficiencies were over 84% under each of the cyclic conditions and increased as the length of the anaerobic period was increased; however, the highest color removal rate was attained for the cycle with the shortest anaerobic period of 3 h. During the decolorization of RBV-5R, two sulfonated aromatic amines (benzene based and naphthalene based) were formed. Additionally, anaerobic azo reductase enzyme was found to be positively affected with the increasing duration of the anaerobic period; however; it was vice versa for the aerobic catechol 2,3-dioxygenase (C23DO) enzyme.

  13. 添加蚯蚓粪对餐厨垃圾厌氧消化过程的影响%Effect of Addition of Earthworm Manure on Anaerobic Digestion Processes of Food Waste

    Institute of Scientific and Technical Information of China (English)

    冯文谦; 李小建; 王德汉; 周振鹏; 邓加曦

    2012-01-01

    以餐厨垃圾为研究对象,在(37±1)℃的条件下,研究了蚯蚓粪的5种不同添加量对餐厨垃圾厌氧消化过程的影响,并考察了在这过程中pH、溶解性化学需氧量(SCOD)、挥发性脂肪酸(VFAs)、总磷(TP)和产气量的变化规律.研究结果表明:当蚯蚓粪的添加量(w,均以湿基计)为0、3%、6%、9%、12%、15%时,餐厨垃圾厌氧消化系统的累积产量分别为14 700、16 074、15 702、16 056、16 414和16 485 mL,产气率分别达到466.35、504.84、488.02、494.03、499.67、496.69 mL·g-1,与不添加蚯蚓粪相比产气率分别提高了8.25%、4.60%、5.93%、7.14%和6.51%,其中当添加量(w)为3%时对餐厨垃圾厌氧消化效果最明显.研究还发现,蚯蚓粪的添加能显著提高各处理的pH和餐厨垃圾的水解酸化速率.可见,添加蚯蚓粪有助于抑制VFAs的累积,使pH更稳定,从而提高沼气产量.%The influences of five different added dosages of earthworm manure on anaerobic digestion of food waste were investigated at (37±1)℃ . The variations of pH, SCOD, VFAs, TP and biogas yield in the anaerobic digestion processes were studied. The experimental results showed that the accumulations of biogas yield were 14 700, 16 074, 15 702, 16 056, 16 414 and 16 485 mL and the biogas yield rate reached 466. 35, 504. 84, 488. 02, 494. 03, 499. 67 and 496. 69 mL·g-1 when the earthworm manure added were 0, 3% , 6% , 9% , 12% and 15% (w, wet substrate) , respectively, and their outputs were increased by 8.25% , 4.60% , 5.93% , 7. 14% and 6.51% , respectively. The earthworm manure could enhance the biogas production most significantly at the dosage of 3%. During the process of the an-aerobic digestion, the addition of earthworm manure could improve the pH value and the hydrogensis and acidogenesis rate of food waste significantly. Therefore, the addition of earthworm manure could prevent VFAs accumulation, buffer the decrease of pH value and increase the

  14. 牛粪对互花米草混合厌氧消化过程的影响研究%Effect of Cow Feces on Anaerobic Digestion Process of Spartina alterniflora

    Institute of Scientific and Technical Information of China (English)

    陈广银; 郑正; 邹星星; 杨世关

    2009-01-01

    以互花米草和牛粪为原料,采用中温(35℃)批式发酵的方式,考察了添加牛粪对互花米草厌氧消化过程的影响.结果表明,互花米草单独发酵时,单位VS产气量为222.61 mL/g,发酵过程出现酸化现象,pH最低为5.60;添加牛粪改善了厌氧微生物的生存环境,提高了系统的缓冲能力,发酵过程未出现酸化现象,pH经短暂下降后很快恢复到7.2~7.5,累积产气量提高了38.83%,互花米草单位VS产气量为309.05 mL/g.混合发酵对消化液中有机酸产量影响不大,但有机酸高峰提前5d出现.FTIR表明,混合发酵促进了微生物对互花米草中易分解有机物的利用.发酵前、后和混合发酵互花米草的结晶度指数C_rI分别为0.617 6、0.620 0和0.615 4.%Effects of cow feces on anaerobic digestion process of Spartina alterniflora was studied by batch model at 35 ℃ .When Spartina alterniflora was digested alone, the biogas yield was 222.61 mL/g,and it was acidified from 10 d to 15 d. When cow feces was added, the environment where microorganisms lived in was meliorated, pH value was stabilized and bingas production was improved by 38.83 % . Volatile fatty acids production was not affected significantly, but the peak was advanced. FTIR and XRD analysis of solid residue substances further proved that co-digestion promoted the removal of carbohydrates and resulted in higher content of lignin than Spartina alterniflora straw digested alone,and promoted the destruction of crystalline of cellulose. The crystallinity index ( C_rI) of Spartina altemiflora, digested Spartina alterniflora and co-digested Spartina alterniflora were 0.6176, 0.6200 and 0.615 4, respectively. Therefore, adding cow feces was beneficial for the decomposition and increasing the biotransformation rate of Spartina alterniflora straw.

  15. Spatial variability of anaerobic processes and wastewater pH in force mains

    DEFF Research Database (Denmark)

    Rudelle, Elise Alice; Nielsen, Asbjørn Haaning; Hvitved-Jacobsen, Thorkild;

    2016-01-01

    The present study focuses on anaerobic organic matter transformation processes in force mains for the purpose of improving existing sewer process models. Wastewater samples were obtained at 100 m intervals from a 1 km long pilot scale force main and measured for several wastewater parameters. Tra....... A significant spatial variablilty was observed for the average transformation rates of all parameters........ Transformation rates for selected parameters were calculated and their spatial variability analyzed. In terms of electron transfer, fermentation was the most significant process, resulting in a net volatile fatty acid formation of 0.83 mmol/L. Sulfate reduction resulted in a production of 0.73 mmol...

  16. Microbial fuel cell based biosensor for in situ monitoring of anaerobic digestion process.

    Science.gov (United States)

    Liu, Zhidan; Liu, Jing; Zhang, Songping; Xing, Xin-Hui; Su, Zhiguo

    2011-11-01

    A wall-jet microbial fuel cell (MFC) was developed for the monitoring of anaerobic digestion (AD). This biofilm based MFC biosensor had a character of being portable, short hydraulic retention time (HRT) for sample flow through and convenient for continuous operation. The MFC was installed in the recirculation loop of an upflow anaerobic fixed-bed (UAFB) reactor in bench-scale where pH of the fermentation broth and biogas flow were monitored in real time. External disturbances to the AD were added on purpose by changing feedstock concentration, as well as process configuration. MFC signals had good correlations with online measurements (i.e. pH, gas flow rate) and offline analysis (i.e. COD) over 6-month operation. These results suggest that the MFC signal can reflect the dynamic variation of AD and can potentially be a valuable tool for monitoring and control of bioprocess.

  17. Hydrogen and methane production from desugared molasses using a two‐stage thermophilic anaerobic process

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2013-01-01

    Hydrogen and methane production from desugared molasses by a two‐stage thermophilic anaerobic process was investigated in a series of two up‐flow anaerobic sludge blanket (UASB) reactors. The first reactor that was dominated with hydrogen‐producing bacteria of Thermoanaerobacterium...... thermosaccharolyticum and Thermoanaerobacterium aciditolerans could generate a high hydrogen production rate of 5600 mL H2/day/L, corresponding to a yield of 132 mL H2/g volatile solid (VS). The effluent from the hydrogen reactor was further converted to methane in the second reactor with the optimal production rate...... of 3380 mL CH4/day/L, corresponding to a yield of 239 mL CH4/g VS. Aceticlastic Methanosarcina mazei was the dominant methanogen in the methanogenesis stage. This work demonstrates that biohydrogen production can be very efficiently coupled with a subsequent step of methane production using desugared...

  18. Inhibitory effects of the macrolide antimicrobial tylosin on anaerobic treatment.

    Science.gov (United States)

    Shimada, Toshio; Zilles, Julie L; Morgenroth, Eberhard; Raskin, Lutgarde

    2008-09-01

    A laboratory-scale anaerobic sequencing batch reactor (ASBR) was operated using a glucose-based synthetic wastewater to study the effects of tylosin, a macrolide antimicrobial commonly used in swine production, on treatment performance. The experimental period was divided into three consecutive phases with different influent tylosin concentrations (0, 1.67, and 167 mg/L). The addition of 1.67 mg/L tylosin to the reactor had negligible effects on the overall treatment performance, that is, total methane production and effluent chemical oxygen demand did not change significantly (P tylosin was added. The addition of 167 mg/L tylosin to the reactor resulted in a gradual decrease in methane production and the accumulation of propionate and acetate. Subsequent inhibition of methanogenesis was attributed to a decrease in the pH of the reactor. After the addition of 167 mg/L tylosin to the reactor, an initial decrease in the rate of glucose uptake during the ASBR cycle followed by a gradual recovery was observed. In batch tests, the specific biogas production with the substrate butyrate was completely inhibited in the presence of tylosin. This study indicated that tylosin inhibited propionate- and butyrate-oxidizing syntrophic bacteria and fermenting bacteria resulting in unfavorable effects on methanogenesis.

  19. The Impact of Chemical Phosphorus Removal on the Process of Anaerobic Sludge Digestion

    Directory of Open Access Journals (Sweden)

    Svetlana Ofverstrom

    2011-02-01

    Full Text Available The paper investigates the efficiency of the mixture of primary sludge and excess activated sludge in Vilnius WWTP with reference to the anaerobic digestion process. Sludge digestion was carried out under laboratory conditions using anaerobic sludge digestion model W8 (Armfield Ltd., UK. Laboratory analyses consist of two periods – the anaerobic digestion of the un-dosed and Fe-dosed sludge mixture. The results of digestion were processed using the methods of statistical analysis. The findings showed reduction in volatile solids approx. by 6% when dosing min FeCl3·6H2O and 15% when dosing max FeCl3·6H2O into feed sludge. Gas volume produced during the digestion of the un-dosed sludge was 90–160 ml/d and 60–125 ml/d in min Fe-dosed sludge and 45-95 ml/d. Also, correlation between VS loadings and biogas production was found. A rise in VS loading from 0,64 g/l/d to 1,01 g/l/d increased biogas production from 90 ml/d to 140–160 ml/d.Article in Lithuanian

  20. Bioelectrochemically-assisted anaerobic composting process enhancing compost maturity of dewatered sludge with synchronous electricity generation.

    Science.gov (United States)

    Yu, Hang; Jiang, Junqiu; Zhao, Qingliang; Wang, Kun; Zhang, Yunshu; Zheng, Zhen; Hao, Xiaodi

    2015-10-01

    Bioelectrochemically-assisted anaerobic composting process (AnCBE) with dewatered sludge as the anode fuel was constructed to accelerate composting of dewatered sludge, which could increase the quality of the compost and harvest electric energy in comparison with the traditional anaerobic composting (AnC). Results revealed that the AnCBE yielded a voltage of 0.60 ± 0.02 V, and total COD (TCOD) removal reached 19.8 ± 0.2% at the end of 35 d. The maximum power density was 5.6 W/m(3). At the end of composting, organic matter content (OM) reduction rate increased to 19.5 ± 0.2% in AnCBE and to 12.9 ± 0.1% in AnC. The fuzzy comprehensive assessment (FCA) result indicated that the membership degree of class I of AnCBE compost (0.64) was higher than that of AnC compost (0.44). It was demonstrated that electrogenesis in the AnCBE could improve the sludge stabilization degree, accelerate anaerobic composting process and enhance composting maturity with bioelectricity generation.

  1. Combined anaerobic-ozonation process for treatment of textile wastewater: removal of acute toxicity and mutagenicity.

    Science.gov (United States)

    Punzi, Marisa; Nilsson, Filip; Anbalagan, Anbarasan; Svensson, Britt-Marie; Jönsson, Karin; Mattiasson, Bo; Jonstrup, Maria

    2015-07-15

    A novel set up composed of an anaerobic biofilm reactor followed by ozonation was used for treatment of artificial and real textile effluents containing azo dyes. The biological treatment efficiently removed chemical oxygen demand and color. Ozonation further reduced the organic content of the effluents and was very important for the degradation of aromatic compounds, as shown by the reduction of UV absorbance. The acute toxicity toward Vibrio fischeri and the shrimp Artemia salina increased after the biological treatment. No toxicity was detected after ozonation with the exception of the synthetic effluent containing the highest concentration, 1 g/l, of the azo dye Remazol Red. Both untreated and biologically treated textile effluents were found to have mutagenic effects. The mutagenicity increased even further after 1 min of ozonation. No mutagenicity was however detected in the effluents subjected to longer exposure to ozone. The results of this study suggest that the use of ozonation as short post-treatment after a biological process can be beneficial for the degradation of recalcitrant compounds and the removal of toxicity of textile wastewater. However, monitoring of toxicity and especially mutagenicity is crucial and should always be used to assess the success of a treatment strategy.

  2. Pretreatment on Anaerobic Sludge for Enhancement of Biohydrogen Production from Cassava Processing Wastewater

    Directory of Open Access Journals (Sweden)

    Franciele do Carmo Lamaison

    2014-02-01

    Full Text Available Methods for the enrichment of an anaerobic sludge with H2-producing bacteria have been compared by using cassava processing wastewater as substrate.The sludge was submitted to three different pretreatments: 1 heat pretreatment by boiling at 98 °C for 15 min., 2 heat pretreatment followed by sludge washout in a Continuous Stirring Tank Reactor (CSTR operated at a dilution rate (D of 0.021 h-1, and 3 sludge washout as the sole enrichment method. The pretreated sludge and the sludge without pretreatment (control were employed in the seeding of 4 batch bioreactors, in order to verify the volume and composition of the generated biogas. Maximum H2 production rates (Rm from the pretreated sludges, were estimated by the modified Gompertz model. Compared to the control, H2 production was ca. 4 times higher for the sludge submitted to the heat pretreatment only and for the sludge subjected to heat pretreatment combined with washout, and 10 times higher for washout. These findings demonstrated that the use of sludge washout as the sole sludge pretreatment method was the most effective in terms of H2 production, as compared to the heat and to the combined heat and washout pretreatments.

  3. Biogas Production through the Anaerobic Digestion of Date Palm Tree Wastes - Process Optimization

    Directory of Open Access Journals (Sweden)

    Fahad Y. Al-Juhaimi

    2014-04-01

    Full Text Available A process for the production of biogas through the anaerobic digestion (AD of date palm tree waste (DPTW was developed. The effects of different substrate pretreatments and operating conditions on the yield of biogas and on the chemical composition of DPTW before and after AD were studied. The best results were obtained using alkali pretreatment, with a particle size of 2 to 5 mm, a C:N ratio of 30:1, a digestion temperature of 40 °C, an initial pH of 7.0, and a volatile solids concentration of approximately 10%. The production of flammable biogas containing up to 50% methane started after about one week of operation and continued for approximately 11 weeks. The highest average biogas yield obtained was 342.2 L gas/kg of volatile solids fed to the digester. The highest maximum and average volumetric biogas production rates obtained were 674.5 and 404.4 L/m3 of digester volume per day, respectively. After digestion, there was up to a 58% reduction in the organic matter content of the substrate. Reductions in the contents of cellulose, hemicellulose, and soluble organic compounds were 68.7, 73.4, and 71.9%, respectively, while the ash and lignin contents remained mostly constant. The remaining sludge contained nutrient minerals and some organic matter which qualifies it as a potential soil fertilizer for crop production.

  4. Effects of lipid concentration on anaerobic co-digestion of municipal biomass wastes

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yifei, E-mail: sunif@buaa.edu.cn [School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Wang, Dian; Yan, Jiao [School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Qiao, Wei [College of Chemical Science and Engineering, China University of Petroleum, Beijing 102249 (China); Wang, Wei [School of Environment, Tsinghua University, Beijing 100084 (China); Zhu, Tianle [School of Chemistry and Environment, Beihang University, Beijing 100191 (China)

    2014-06-01

    Highlights: • Lipid in municipal biomass would not inhibited the anaerobic digestion process. • A lipid concentration of 65% of total VS was the inhibition concentration. • The amount of Brevibacterium decreased with the increasing of the lipid contents. • Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process. - Abstract: The influence of the lipid concentration on the anaerobic co-digestion of municipal biomass waste and waste-activated sludge was assessed by biochemical methane potential (BMP) tests and by bench-scale tests in a mesophilic semi-continuous stirred tank reactor. The effect of increasing the volatile solid (VS) concentration of lipid from 0% to 75% was investigated. BMP tests showed that lipids in municipal biomass waste could enhance the methane production. The results of bench-scale tests showed that a lipids concentration of 65% of total VS was the inhibition concentration. Methane yields increased with increasing lipid concentration when lipid concentrations were below 60%, but when lipid concentration was set as 65% or higher, methane yields decreased sharply. When lipid concentrations were below 60%, the pH values were in the optimum range for the growth of methanogenic bacteria and the ratios of volatile fatty acid (VFA)/alkalinity were in the range of 0.2–0.6. When lipid concentrations exceeded 65%, the pH values were below 5.2, the reactor was acidized and the values of VFA/alkalinity rose to 2.0. The amount of Brevibacterium decreased with increasing lipid content. Long chain fatty acids stacked on the methanogenic bacteria and blocked the mass transfer process, thereby inhibiting anaerobic digestion.

  5. Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor.

    Science.gov (United States)

    Ge, Huoqing; Batstone, Damien; Keller, Jurg

    2016-01-01

    The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

  6. Pig slurry concentration by vacuum evaporation: influence of previous mesophilic anaerobic digestion process.

    Science.gov (United States)

    Bonmatí, August; Flotats, Xavier

    2003-01-01

    Water can be removed from pig slurry by evaporation, through the application of wasted heat from a power plant or from other processes. Apart from obtaining a concentrate with an obviously higher nutrient concentration than the original slurry, another objective of water removal is to obtain water as condensate, which could be reused. The objective of this work was to study the vacuum evaporation of pig slurry liquid fraction and to evaluate condensate composition as a function of both pH (4, 5, and 6) and pig slurry type (fresh slurry and anaerobically digested slurry). Batch experiments showed that condensate characteristics, total ammonia nitrogen (NH3-N), volatile fatty acids (VFA), and chemical oxygen demand were strongly dependent on initial slurry pH. In addition to producing part of the required thermal energy, previous anaerobic digestion presented several other clear advantages. The consumption of VFA and other volatile organic compounds during anaerobic digestion reduced the volatilization of organic matter in the evaporation treatment and, consequently, provided a higher quality condensate.

  7. Integration of a Water Scrubbing Technique and Two-Stage Pressurized Anaerobic Digestion in One Process

    Directory of Open Access Journals (Sweden)

    Andreas Lemmer

    2015-03-01

    Full Text Available Two-stage pressurized anaerobic digestion is a promising technology. This technology integrates in one process biogas production with upgrading and pressure boosting for grid injection. To investigate whether the efficiency of this novel system could be further increased, a water scrubbing system was integrated into the methanogensis step. Therefore, six leach-bed reactors were used for hydrolysis/acidification and a 30-L pressurized anaerobic filter operated at 9 bar was adopted for acetogenesis/methanogenesis. The fermentation liquid of the pressurized anaerobic filter was circulated periodically via a flash tank, operating at atmospheric pressure. Due to the pressure drop, part of dissolved carbon dioxide was released from the liquid phase into the flash tank. The depressurized fermentation liquid was then recycled to the pressurized reactor. Three different flow rates (0 L·day−1, 20 L·day−1 and 40 L·day−1 were tested with three repetitions. As the daily recycled flashed liquid flow was increased from 0 to 40 L, six times as much as the daily feeding, the methane content in the biogas increased from 75 molar percent (mol% to 87 mol%. The pH value of the substrate in the methane reactor rose simultaneously from 6.5 to 6.7. The experimental data were verified by calculation.

  8. Decolorization and biogas production by an anaerobic consortium: effect of different azo dyes and quinoid redox mediators.

    Science.gov (United States)

    Alvarez, L H; Valdez-Espinoza, R; García-Reyes, R B; Olivo-Alanis, D; Garza-González, M T; Meza-Escalante, E R; Gortáres-Moroyoqui, P

    2015-01-01

    The inhibitory effect of azo dyes and quinoid compounds on an anaerobic consortium was evaluated during a decolorization process and biogas production. In addition, the impact of quinoid compounds such as lawsone (LAW) and anthraquinone-2,6-disulfonate (AQDS) on the rate of decolorization of Direct Blue 71 (DB71) was assessed. The anaerobic consortium was not completely inhibited under all tested dye concentrations (0.1-2 mmol l(-1)), evidenced by an active decolorization process and biogas production. The presence of quinoid compounds at different concentrations (4, 8, and 12 mmol l(-1)) also inhibited biogas production compared to the control incubated without the quinoid compounds. In summary, the anaerobic consortium was affected to a greater extent by increasing the quantity of azo dyes or quinoid compounds. Nevertheless, at a lower concentration (1 mmol l(-1)) of quinoid compounds, the anaerobic consortium effectively decolorized 2 mmol l(-1) of DB71, increasing up to 5.2- and 20.4-fold the rate of decolorization with AQDS and LAW, respectively, compared to the control lacking quinoid compounds.

  9. Anaerobic Digestion of the Organic Fraction of Municipal Solid Waste With Recirculation of Process Water

    DEFF Research Database (Denmark)

    Hartmann, H.; Angelidaki, Irini; Ahring, Birgitte Kiær

    2001-01-01

    A new concept of a wet anaerobic digestion treatment of the organic fraction of municipal solid waste (OFMSW) is investigated. Once the waste is diluted with water, the entire liquid fraction of the effluent is recirculated and used as process water for dilution of the waste. This enables a well......-mixed process without additional water supply. A methane yield of 400 and 445 ml/gVS from OFMSW was achieved in batch and reactor experiments, respectively. Reactor performance with 15 days retention time and an organic loading rate of 4.5 gVS/ld was stable with low VFA concentrations and a VS reduction of 70...

  10. The effect of SRT on nitrate formation during autotrophic nitrogen removal of anaerobically treated wastewater.

    Science.gov (United States)

    Lee, Po-Heng; Kwak, Wonji; Bae, Jeaho; McCarty, Perry L

    2013-01-01

    Autotrophic nitrogen removal, coupling nitritation (ammonium to nitrite) with anaerobic ammonium oxidation (anammox), offers a promising nitrogen-removal alternative, especially for post-treatment of anaerobically-treated wastewater. However, previous reports suggest that less than 90% total nitrogen removal should be expected with this process alone because over 10% of the ammonium removed will be converted to nitrate. This is caused because nitrite conversion to nitrate is required for reduction of carbon dioxide to cell carbon. However, recent research results suggest that more limited nitrate formation of only a few per cent sometimes occurs. It was hypothesized such lower nitrate yields may result from use of long solids retention times (SRT) where net biological yields are low, and providing that the ratio of oxygen added to influent ammonium concentrations is maintained at or below 0.75 mol/mol. Overall reaction equations were developed for each process and combined to evaluate the potential effect of SRT on process stoichiometry. The results support the use of a long SRT to reduce net cell yield, which in turn results in a small percentage conversion to nitrate during ammonium removal and high total nitrogen removals in the range of 90 to 94%.

  11. 温度对污泥厌氧发酵产酸过程的影响%Effects of Temperature on Acidogenic Process in Anaerobic Fermentation for Sewage Sludge

    Institute of Scientific and Technical Information of China (English)

    蔡伟娜; 陆小青

    2011-01-01

    污泥厌氧发酵不仅可以产生短链脂肪酸补充污水脱氮除磷[1]工艺中碳源的不足,还可以实现污泥的减量化和资源化.该文综述了温度对污泥厌氧发酵产酸影响的研究进展,着重讨论了温度对污泥厌氧发酵过程中水解、短链脂肪酸(SCFAs)累积、甲烷的产生和污泥减量化等方面的影响,并对今后的研究方向进行了展望.%The use of short chain fatty acids (SCFAs)-richened fermentation liquid as the additional carbon source of biological nutrient removal (BNR) has been considered as a practical and sustainable solution for increasing BNR performance, by which both waste bio-solids utilization and internal carbon source production can be accomplished in the biological wastewater treatment plants. According to the latest research, the sludge anaerobic fermentations under different temperatures were reviewed in this paper. The effect of temperature on hydrolysis, acidification, methane production and sludge reduce was discussed in details in this paper. The research direction in the future was put forward.

  12. The Effect of Effluent Recirculation in a Semi-Continuous Two-Stage Anaerobic Digestion System

    Directory of Open Access Journals (Sweden)

    Karthik Rajendran

    2013-06-01

    Full Text Available The effect of recirculation in increasing organic loading rate (OLR and decreasing hydraulic retention time (HRT in a semi-continuous two-stage anaerobic digestion system using stirred tank reactor (CSTR and an upflow anaerobic sludge bed (UASB was evaluated. Two-parallel processes were in operation for 100 days, one with recirculation (closed system and the other without recirculation (open system. For this purpose, two structurally different carbohydrate-based substrates were used; starch and cotton. The digestion of starch and cotton in the closed system resulted in production of 91% and 80% of the theoretical methane yield during the first 60 days. In contrast, in the open system the methane yield was decreased to 82% and 56% of the theoretical value, for starch and cotton, respectively. The OLR could successfully be increased to 4 gVS/L/day for cotton and 10 gVS/L/day for starch. It is concluded that the recirculation supports the microorganisms for effective hydrolysis of polyhydrocarbons in CSTR and to preserve the nutrients in the system at higher OLRs, thereby improving the overall performance and stability of the process.

  13. Effects of ferric iron on the anaerobic treatment and microbial biodiversity in a coupled microbial electrolysis cell (MEC)--anaerobic reactor.

    Science.gov (United States)

    Zhang, Jingxin; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2013-10-01

    Adding Fe(III) into a MEC - anaerobic reactor enhanced the degradation of organic matters. To clarify the respective effects of combining Fe(III) dosage and a MEC and Fe(III) dosage only on strengthening anaerobic digestion, three anaerobic reactors were operated in parallel: a MEC - anaerobic reactor with dosing Fe(OH)3 (R1), an anaerobic reactor with dosing Fe(OH)3 (R2) and a common anaerobic reactor (R3). With increasing influent COD from 1500 to 4000 mg/L, the COD removal in R1 was maintained at 88.3% under a voltage of 0.8 V, which was higher than that in reactor R2 and R3. When the power was cut off, the COD removal in R1 decreased by 5.9%. The addition of Fe(OH)3 enhanced both anaerobic digestion and anodic oxidation, resulting in the effective mineralization of volatile fatty acids (VFAs). The reduced Fe(II) combined with electric field resulted more extracellular polymeric substances (EPS) production. Quantitative real - time PCR showed a higher abundance of bacteria in the anodic biofilm and R1. Pyrosequencing and denaturing gradient gel electrophoresis (DGGE) analysis revealed that the dominant bacteria and archaea communities were richer and more abundant in the anode biofilm and R1.

  14. [Pilot study of thermal treatment/thermophilic anaerobic digestion process treating waste activated sludge of high solid content].

    Science.gov (United States)

    Wu, Jing; Wang, Guang-qi; Cao, Zhi-ping; Li, Zhong-hua; Hu, Yu-ying; Wang, Kai-jun; Zu, Jian-e

    2014-09-01

    A pilot-scale experiment about the process of "thermal pretreatment at 70°C/thermophilic anaerobic digestion" of waste activated sludge of high solid content (8% -9% ) was conducted. The process employed thermal treatment of 3 days to accelerate the hydrolysis and thermophilic digestion to enhance anaerobic reaction. Thus it was good at organic removal and stabilization. When the solid retention time (SRT) was longer than 20 days, the VSS removal rate was greater than 42. 22% and it was linearly correlated to the SRT of the aerobic digestion with the R2 of 0. 915 3. It was suggested that SRT of anaerobic digestion was 25 days in practice. VSS removal rate and biogas production rate of the pilot experiment were similar to those of the run-well traditional full-scale sludge anaerobic digestion plants (solid content 3% -5% ) and the plant of high solid content using German technique.

  15. Bioaugmentation of anaerobic sludge digestion with iron-reducing bacteria: process and microbial responses to variations in hydraulic retention time.

    Science.gov (United States)

    Baek, Gahyun; Kim, Jaai; Shin, Seung Gu; Lee, Changsoo

    2016-01-01

    Although anaerobic digestion (AD) is a widely used option to manage waste activated sludge (WAS), there are some drawbacks related to its slow reaction rate and low energy productivity. This study examined an anaerobic WAS digester, augmented with an iron-reducing microbial consortium, relative to changes in microbial community structure and process performance at decreasing hydraulic retention times (HRTs) of 20 to 10 days. The enhanced methanation performance (approximately 40 % increase in methane yield) by the bioaugmentation was sustained until the HRT was decreased to 12.5 days, under Fe(3+)-rich conditions (ferric oxyhydroxide, 20 mM Fe). Enhanced iron-reducing activity was evidenced by the increased Fe(2+) to total Fe ratio maintained above 50 % during the stable operational phases. A further decrease in HRT to 10 days resulted in a significant performance deterioration, along with a drop in the Fe(2+) to total Fe ratio to <35 %, after four turnovers of operation. Prevailing existence of putative iron-reducing bacteria (IRBs) was identified by denaturing gradient gel electrophoresis (DGGE), with Spirochaetaceae- and Thauera-related organisms being dominant members, and clear dominance shifts among them with respect to decrease in HRT were observed. Lowering HRT led to evident shifts in bacterial community structure likely associated with washout of IRBs, leading to decreases in iron respiration activity and AD performance at a lower HRT. The bacterial community structure shifted dynamically over phases, and the community transitions correlated well with the changes in process performance. Overall, the combined biostimulation and bioaugmentation investigated in this study proved effective for enhanced methane recovery from anaerobic WAS digestion, which suggests an interesting potential for high-rate AD.

  16. The effects of anaerobic training in serum lipids and arachidonic acid metabolites

    Directory of Open Access Journals (Sweden)

    GEORGIOS KIPREOS

    2010-01-01

    Full Text Available Coronary arteries are subjected daily in high shear stress and manifest atherosclerosis very early in life in comparison to other arteries in the human body. Some factors that are implicated in the evolution and progress of this process are the concentration of lipids and arachidonic acid metabolites, such prostacyclin and thromboxane. It has been reported that those who participate in aerobic activities such as walking, cycling, jogging or brisk walking might have normal values of the mentioned chemical substances. On the other hand, it is reported that the effects of anaerobic and strength activities has negative effects on the vascular endothelium, which is essential for the maintenance of hemostatic balance and the local regulation of vascular tone.Therefore, even although extensive research has been conducted in this field, there are crucial gaps in our knowledge. Consequently, the purpose of this brief review is to describe what is known about the effects of anaerobic activities in which the competitive athletes have participated on the following blood parameters: Total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL - C, low density lipoproteins cholesterol (LDL - C, prostacyclin & thromboxane.

  17. Effects of inoculating microorganisms on mesophilic anaerobic digestion of septic sludge

    Institute of Scientific and Technical Information of China (English)

    黄川; 谷伟; 王里奥; 宋珍霞

    2009-01-01

    The anaerobic digestion of septic sludge was studied through inoculating effective microorganisms (EMs) under mesophilic condition (35 ℃). The variation of COD,total solid (TS),volatile solid (VS),pH value and the gas production rate during the digestion process were presented,and the optimal adding concentration of EMs was determined by comparing the reduction effectiveness of septic sludge. The results show that proper addition of EMs can enhance acid buffering capacity of the system,and the NH3-N concentration is lower than inhibition concentration of 2 g/L reported in the literature and maintain the range of pH value which is suitable for both hydrolysis-acidification and methanogenesis. However,overdose of EMs can reduce the initial pH value of septic sludge and decrease the effects of the anaerobic digestion. EMs can increase the quantity of microbe in septic sludge and improve the gas production and generation rate over a period of time. But overdosing EMs can lead to low pH,restrain activity of methanogenic bacteria and affect the quantity and the generation rate of gas. Adding 0.01% EMs achieves the highest sludge reduction with the removal rates of TS,VS and COD by 32.51%,42.34% and 40.97%,respectively.

  18. Bio-electrolytic sensor for rapid monitoring of volatile fatty acids in anaerobic digestion process

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Li, Xiaohu; Zhao, Nannan;

    2017-01-01

    This study presents an innovative biosensor that was developed on the basis of a microbial electrolysis cell for fast and reliable measurement of volatile fatty acids (VFA) during anaerobic digestion (AD) process. The bio-electrolytic sensor was first tested with synthetic wastewater containing...... to monitor VFA concentrations in a lab-scale AD reactor for a month. The VFA measurements from the sensor correlated well with those from GC analysis which proved the accuracy of the system. Since hydrogen was produced in the cathode as byproduct during monitoring, the system could be energy self...

  19. Effect of antimicrobial compounds tylosin and chlortetracycline during batch anaerobic swine manure digestion.

    Science.gov (United States)

    Stone, James J; Clay, Sharon A; Zhu, Zhenwei; Wong, Kwok L; Porath, Laura R; Spellman, Garth M

    2009-10-01

    Tylosin and chlortetracycline (CTC) are antimicrobial chemicals that are fed to >45% of the US swine herds at therapeutic and sub-therapeutic dosages to enhance growth rates and treat swine health problems. These compounds are poorly absorbed during digestion so that the bioactive compound or metabolites are excreted. This study investigated the degradation and stabilization of swine manure that contained no additives and compared the observed processes with those of manure containing either tylosin or CTC. The batch anaerobic incubation lasted 216 days. The breakdown of insoluble organic matter through anaerobic hydrolysis reactions was faster for manure containing CTC compared with tylosin or no-antimicrobial treatments. Volatile fatty acid (VFA) accumulation, including acetate, butyrate, and propionate, was greater for CTC-containing manure compared to tylosin and no-antimicrobial treatments. The relative abundance of two aceticlastic methanogens, Methanosaetaceae and Methanosarcinaceae spp., were less for CTC manure than manure with no-antimicrobial treatment. In addition, generation of methane and carbon dioxide was inhibited by 27.8% and 28.4%, respectively, due to the presence of CTC. Tylosin effects on manure degradation were limited, however the relative abundance of Methanosarcinaceae spp. was greater than found in the CTC or no-antimicrobial manures. These data suggest that acetate and other C-1 VFA compounds would be effectively utilized during methanogenesis in the presence of tylosin.

  20. Process and device for anaerobic removal of organic substrates. Verfahren und Vorrichtung zum anaeroben Abbau organischer Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, H.

    1984-09-06

    In a process for the anaerobic removal of organic substrates, these are treated in two separate anaerobic reactors 1 and 2. One anaerobic reactor 1 is used as an acid-forming reactor, while the other anaerobic reactor 2 is made as a reactor for forming acetates and methane with a biogas outflow pipe. A drain 3 is used to take partly treated organic substrate from the acid-forming reactor to the reactor forming the acetate and methane. In order to reduce or exclude the proportion of CO/sub 2/ in biogas pipe 5 in a simple and economical way, carbondioxide is removed from drain 3 of the acid-forming reactor 1. The removal of the carbondioxide is preferably done in a stripping device 6 situated in drain 3, to which an air intake pipe 7 and an air outlet pipe 8 are connected.

  1. Anaerobic Membrane Bioreactors For Cost-Effective Municipal Water Reuse

    NARCIS (Netherlands)

    Özgün, H.

    2015-01-01

    In recent years, anaerobic membrane bioreactor (AnMBR) technology has been increasingly researched for municipal wastewater treatment as a means to produce nutrient-rich, solids free effluents with low levels of pathogens, while occupying a small footprint. An AnMBR can be used not only for on-site

  2. EFFECT OF SULPHATE ON LOW-TEMPERATURE ANAEROBIC DIGESTION

    Directory of Open Access Journals (Sweden)

    Padhraig eMadden

    2014-07-01

    Full Text Available The effect of sulphate addition on the stability of, and microbial community behaviour in, low-temperature anaerobic expanded granular sludge bed-based bioreactors was investigated at 15°C. Efficient bioreactor performance was observed, with chemical oxygen demand removal efficiencies of >90%, and a mean SO42- removal rate of 98.3%. In situ methanogensis appeared unaffected at a COD:SO42- influent ratio of 8:1, and subsequently of 3:1, and was impacted marginally only when the COD: SO42- ratio was 1:2. . Specific methanogenic activity assays indicated a complex set of interactions between sulphate-reducing bacteria (SRB, methanogens and homoacetogenic bacteria. SO42- addition resulted in predominantly acetoclastic, rather than hydrogenotrophic, methanogenesis until >600 days of SO42--influenced bioreactor operation. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE of 16S rRNA genes. Fluorescence in situ hybridisations (FISH, qPCR and microsensor analysis were combined to investigate the distribution of microbial groups, and particularly SRB and methanogens, along the structure of granular biofilms. qPCR data indicated that sulphidogenic genes were present in methanogenic and sulfidogenic biofilms, indicating the potential for sulphate reduction even in bioreactors not exposed to SO42-. Although the architecture of methanogenic and sulphidogenic granules was similar, indicating the presence of SRB even in methanogenic systems, FISH with rRNA targets found that the SRB were more abundant in the sulphidogenic biofilms. Methanosaeta species were the predominant, keystone members of the archaeal community, with the complete absence of the Methanosarcina species in the experimental bioreactor by trial conclusion. Microsensor data suggested the ordered distribution of sulphate reduction and sulphide accumulation, even in methanogenic granules.

  3. Effect of sulfate on low-temperature anaerobic digestion.

    Science.gov (United States)

    Madden, Pádhraig; Al-Raei, Abdul M; Enright, Anne M; Chinalia, Fabio A; de Beer, Dirk; O'Flaherty, Vincent; Collins, Gavin

    2014-01-01

    The effect of sulfate addition on the stability of, and microbial community behavior in, low-temperature anaerobic expanded granular sludge bed-based bioreactors was investigated at 15°C. Efficient bioreactor performance was observed, with chemical oxygen demand (COD) removal efficiencies of >90%, and a mean SO(2-) 4 removal rate of 98.3%. In situ methanogensis appeared unaffected at a COD: SO(2-) 4 influent ratio of 8:1, and subsequently of 3:1, and was impacted marginally only when the COD: SO(2-) 4 ratio was 1:2. Specific methanogenic activity assays indicated a complex set of interactions between sulfate-reducing bacteria (SRB), methanogens and homoacetogenic bacteria. SO(2-) 4 addition resulted in predominantly acetoclastic, rather than hydrogenotrophic, methanogenesis until >600 days of SO(2-) 4-influenced bioreactor operation. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes. Fluorescence in situ hybridizations (FISH), qPCR and microsensor analysis were combined to investigate the distribution of microbial groups, and particularly SRB and methanogens, along the structure of granular biofilms. qPCR data indicated that sulfidogenic genes were present in methanogenic and sulfidogenic biofilms, indicating the potential for sulfate reduction even in bioreactors not exposed to SO(2-) 4. Although the architecture of methanogenic and sulfidogenic granules was similar, indicating the presence of SRB even in methanogenic systems, FISH with rRNA targets found that the SRB were more abundant in the sulfidogenic biofilms. Methanosaeta species were the predominant, keystone members of the archaeal community, with the complete absence of the Methanosarcina species in the experimental bioreactor by trial conclusion. Microsensor data suggested the ordered distribution of sulfate reduction and sulfide accumulation, even in methanogenic granules.

  4. Subsurface aeration of anaerobic groundwater : iron colloid formation and the nitrification process

    NARCIS (Netherlands)

    Wolthoorn, A.

    2003-01-01

    Keywords: Iron, anaerobic groundwater, groundwater purification, heterogeneous oxidation, iron colloid formation, electron microscopy, nitrification In anaerobic groundwater iron and ammonium can be found in relatively high concentrations. These substances need to be removed when groundwater is used

  5. Biogas production and methanogenic archaeal community in mesophilic and thermophilic anaerobic co-digestion processes.

    Science.gov (United States)

    Yu, D; Kurola, J M; Lähde, K; Kymäläinen, M; Sinkkonen, A; Romantschuk, M

    2014-10-01

    Over 258 Mt of solid waste are generated annually in Europe, a large fraction of which is biowaste. Sewage sludge is another major waste fraction. In this study, biowaste and sewage sludge were co-digested in an anaerobic digestion reactor (30% and 70% of total wet weight, respectively). The purpose was to investigate the biogas production and methanogenic archaeal community composition in the anaerobic digestion reactor under meso- (35-37 °C) and thermophilic (55-57 °C) processes and an increasing organic loading rate (OLR, 1-10 kg VS m(-3) d(-1)), and also to find a feasible compromise between waste treatment capacity and biogas production without causing process instability. In summary, more biogas was produced with all OLRs by the thermophilic process. Both processes showed a limited diversity of the methanogenic archaeal community which was dominated by Methanobacteriales and Methanosarcinales (e.g. Methanosarcina) in both meso- and thermophilic processes. Methanothermobacter was detected as an additional dominant genus in the thermophilic process. In addition to operating temperatures, the OLRs, the acetate concentration, and the presence of key substrates like propionate also affected the methanogenic archaeal community composition. A bacterial cell count 6.25 times higher than archaeal cell count was observed throughout the thermophilic process, while the cell count ratio varied between 0.2 and 8.5 in the mesophilic process. This suggests that the thermophilic process is more stable, but also that the relative abundance between bacteria and archaea can vary without seriously affecting biogas production.

  6. Recovery of methane from anaerobic process effluent using poly-di-methyl-siloxane membrane contactors.

    Science.gov (United States)

    Cookney, J; Cartmell, E; Jefferson, B; McAdam, E J

    2012-01-01

    This paper demonstrates the potential for recovering dissolved methane from low temperature anaerobic processes treating domestic wastewater. In the absence of methane recovery, ca. 45% of the produced methane is released as a fugitive emission which results in a net carbon footprint of -0.47 kg CO(2e) m(-3). A poly-di-methyl-siloxane (PDMS) membrane contactor was applied to support sweep gas desorption of dissolved methane using nitrogen. The dense membrane structure controlled gaseous mass transfer thus recovery was maximised at low liquid velocities. At the lowest liquid velocity, V(L), of 0.0025 m s(-1), 72% of the dissolved methane was recovered. A vacuum was also trialled as an alternative to sweep-gas operation. At vacuum pressures below 30 mbar, reasonable methane recovery was observed at an intermediate V(L) of 0.0056 m s(-1). Results from this study demonstrate that dissolved methane recovery could increase net electrical production from low temperature anaerobic processes by ca. +0.043 kWh(e) m(-3) and reduce the net carbon footprint to +0.01 kg CO(2e) m(-3). However, further experimental work to optimise the gas-side hydrodynamics is required as well as validation of the long-term impacts of biofouling on process performance.

  7. Concentration of pig slurry by evaporation: anaerobic digestion as the key process.

    Science.gov (United States)

    Bonmatí, A; Campos, E; Flotats, X

    2003-01-01

    Nutrient redistribution between areas with a structural pig slurry surplus and those with a shortage, is limited by the high cost of transportation and spreading, due to the high water content in slurry (more than 90%) and its relative low nutrient concentration. Water can be removed from slurry by evaporation, through the application of waste heat from a power plant or from other processes. Apart from obtaining a concentrate with an obviously higher nutrient concentration than the original slurry, another objective is to obtain clean water as condensate. The objective of this work was to study the batch vacuum evaporation of pig slurry liquid fraction, to evaluate the economic feasibility and to evaluate condensate quality as a function of both pH (4, 5 and 6) and pig slurry type (fresh slurry and anaerobically digested slurry). Results showed that condensate characteristics (ammonia nitrogen, VFA, COD) were strongly dependent on these variables. Previous anaerobic digestion presented clear advantages: it provided a fraction of the required energy and it removed organic matter, preventing its volatilisation in the evaporation process and providing higher quality condensates. These advantages make the combined treatment strategy economically more feasible than the evaporation process alone.

  8. Activated zeolite--suitable carriers for microorganisms in anaerobic digestion processes?

    Science.gov (United States)

    Weiß, S; Lebuhn, M; Andrade, D; Zankel, A; Cardinale, M; Birner-Gruenberger, R; Somitsch, W; Ueberbacher, B J; Guebitz, G M

    2013-04-01

    Plant cell wall structures represent a barrier in the biodegradation process to produce biogas for combustion and energy production. Consequently, approaches concerning a more efficient de-polymerisation of cellulose and hemicellulose to monomeric sugars are required. Here, we show that natural activated zeolites (i.e. trace metal activated zeolites) represent eminently suitable mineral microhabitats and potential carriers for immobilisation of microorganisms responsible for anaerobic hydrolysis of biopolymers stabilising related bacterial and methanogenic communities. A strategy for comprehensive analysis of immobilised anaerobic populations was developed that includes the visualisation of biofilm formation via scanning electron microscopy and confocal laser scanning microscopy, community and fingerprint analysis as well as enzyme activity and identification analyses. Using SDS polyacrylamide gel electrophoresis, hydrolytical active protein bands were traced by congo red staining. Liquid chromatography/mass spectroscopy revealed cellulolytical endo- and exoglucanase (exocellobiohydrolase) as well as hemicellulolytical xylanase/mannase after proteolytic digestion. Relations to hydrolytic/fermentative zeolite colonisers were obtained by using single-strand conformation polymorphism analysis (SSCP) based on amplification of bacterial and archaeal 16S rRNA fragments. Thereby, dominant colonisers were affiliated to the genera Clostridium, Pseudomonas and Methanoculleus. The specific immobilisation on natural zeolites with functional microbes already colonising naturally during the fermentation offers a strategy to systematically supply the biogas formation process responsive to population dynamics and process requirements.

  9. Nitrogen removal from sludge dewatering effluent through anaerobic ammonia oxidation process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shao-hui; ZHENG Ping; HUA Yu-mei

    2005-01-01

    Anaerobic ammonia oxidation(Anammox) process is a novel and promising wastewater nitrogen removal process. The feasibility of transition of Anammox from denitrification and the performance of lab-scale Anammox biofilm reactor were investigated with sludge dewatering effluent. The results showed that Anammox process could be successfully started up after cultivation of denitrification biofilm and using it as inoculum. The transition of Anammox from denitrification was accomplished within 85 d. Anammox process was found suitable to remove ammonia from sludge dewatering effluent. The effluent ammonia concentration was detected to be 23.11 mgN/L at HRT of 28 h when influent ammonia concentration was fed 245 mgN/L, which was less than that for the national discharge standard Ⅱ (25 mgN/L) of 243.25 mg NH4+ -N/L and 288.31 mg NO2- -N/L.

  10. Reductive transformation and detoxification mechanism of 2,4-dinitrochlorobenzene in combined zero valent iron and anaerobic-aerobic process

    Institute of Scientific and Technical Information of China (English)

    Jinyou Shen; Zongyuan Zhou; Changjin Ou; Xiuyun Sun; Jiansheng Li; Weiqing Han; Lin Zhou; Lianjun Wang

    2012-01-01

    A combined zero valent iron (ZVI) and anaerobic-aerobic process was adopted for the treatment of 2,4-dinitrochlorobenzene (DNCB)-containing wastewater.The transformation pathway,reduction of acute toxicity and enhancement of biodegradability were investigated.After pretreatment by ZVI,DNCB in wastewater could be completely converted into 2,4-diaminochlorobenzene (DACB).The ratio of BOD5/COD increased from 0.005 ± 0.001 to 0.168 ± 0.007,while EC50,48 hr (V/V) increased from 0.65% to 5.20%,indicating the enhancement of biodegradability and reduction of acute toxicity with the pretreatment by ZVI.DACB was further dechlorinated to m-phenylenediamine during the anaerobic process using methanol as electron donor,with EC50,48 hr increasing from 5.20% to 48.2%.After the subsequent anaerobic-aerobic process,m-phenylenediamine was degraded completely,with effluent COD of 67.5 ± 10.8 mg/L.This effluent of the subsequent anaerobic-aerobic process was not toxic to zebrafish.The combined ZVI and anaerobic-aerobic process offers bright prospects for the treatment of chlorinated nitroaromatic compound-containing wastewater.

  11. Anaerobic digestion of poplar processing residues for methane production after alkaline treatment.

    Science.gov (United States)

    Yao, Yiqing; He, Mulan; Ren, Yubing; Ma, Liying; Luo, Yang; Sheng, Hongmei; Xiang, Yun; Zhang, Hua; Li, Qien; An, Lizhe

    2013-04-01

    Poplar processing residues were used for methane production by anaerobic digestion after alkaline treatment and methane production was measured. The highest methane production of 271.9 L/kg volatile solid (VS) was obtained at conditions of 35 g/L and 5.0% NaOH, which was 113.8% higher than non-alkaline treated samples, and 28.9% higher than that of corn straw, which is the conventional anaerobic digestion material in China. The maximal enhancement of 275.5% obtained at conditions of 50 g/L and 7.0% NaOH. Degradation of cellulose, hemicellulose and lignin after treatment increased by 4.0-9.0%, 3.3-6.2%, and 11.1-20.5%, respectively, with NaOH dose ranged from 3.0% to 7.0%. Scanning electron microscopy (SEM), FTIR spectra and Crystallinity measurements showed that the lignocellulosic structures were disrupted by NaOH. The results indicate poplar processing residues might be an efficient substrate for methane production after alkaline treatment.

  12. Effect of substrate concentration on dark fermentation hydrogen production using an anaerobic fluidized bed reactor.

    Science.gov (United States)

    de Amorim, Eduardo Lucena Cavalcante; Sader, Leandro Takano; Silva, Edson Luiz

    2012-03-01

    The effect of substrate (glucose) concentration on the stability and yield of a continuous fermentative process that produces hydrogen was studied. Four anaerobic fluidized bed reactors (AFBRs) were operated with a hydraulic retention time (HRT) from 1 to 8 h and an influent glucose concentration from 2 to 25 g L(-1). The reactors were inoculated with thermally pre-treated anaerobic sludge and operated at a temperature of 30 °C with an influent pH around 5.5 and an effluent pH of about 3.5. The AFBRs with a HRT of 2 h and a feed strength of 2, 4, and 10 g L(-1) showed satisfactory H(2) production performance, but the reactor fed with 25 g L(-1) of glucose did not. The highest hydrogen yield value was obtained in the reactor with a glucose concentration of 2 g L(-1) when it was operated at a HRT of 2 h. The maximum hydrogen production rate value was achieved in the reactor with a HRT of 1 h and a feed strength of 10 g L(-1). The AFBRs operated with glucose concentrations of 2 and 4 g L(-1) produced greater amounts of acetic and butyric acids, while AFBRs with higher glucose concentrations produced a greater amount of solvents.

  13. Enhanced coproduction of hydrogen and methane from cornstalks by a three-stage anaerobic fermentation process integrated with alkaline hydrolysis.

    Science.gov (United States)

    Cheng, Xi-Yu; Liu, Chun-Zhao

    2012-01-01

    A three-stage anaerobic fermentation process including H(2) fermentation I, H(2) fermentation II, methane fermentation was developed for the coproduction of hydrogen and methane from cornstalks. Hydrogen production from cornstalks using direct microbial conversion by Clostridium thermocellum 7072 was markedly enhanced in the two-stage thermophilic hydrogen fermentation process integrated with alkaline treatment. The highest total hydrogen yield from cornstalks in the two-stage fermentation process reached 74.4 mL/g-cornstalk. The hydrogen fermentation effluents and alkaline hydrolyzate were further used for methane fermentation by anaerobic granular sludge, and the total methane yield reached 205.8 mL/g-cornstalk. The total energy recovery in the three-stage anaerobic fermentation process integrated with alkaline hydrolysis reached 70.0%.

  14. Comprehensive microbial analysis of combined mesophilic anaerobic-thermophilic aerobic process treating high-strength food wastewater

    DEFF Research Database (Denmark)

    Jang, Hyun Min; Ha, Jeong Hyub; Park, Jong Moon

    2015-01-01

    A combined mesophilic anaerobic-thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic...... reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT)=40d (corresponding OLR=3.5kgCOD/m3 d) and Run II with HRT=20d...... (corresponding OLR=7kgCOD/m3). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher...

  15. Central treatment of different emulsion wastewaters by an integrated process of physicochemically enhanced ultrafiltration and anaerobic-aerobic biofilm reactor.

    Science.gov (United States)

    Zhang, Weijun; Xiao, Ping; Wang, Dongsheng

    2014-05-01

    The feasibility of an integrated process of ultrafiltration (UF) enhanced by combined chemical emulsion breaking with vibratory shear and anaerobic/aerobic biofilm reactor for central treatment of different emulsion wastewaters was investigated. Firstly, it was found that calcium chloride exhibited better performance in oil removal than other inorganic salts. Chemical demulsification pretreatment could efficiently improve oil removal and membrane filtration in emulsion wastewater treatment by VSEP. According to aerobic batch bioassay, UF permeate exhibited good biodegradability and could be further treated with biological process. Additionally, pilot test indicated that anaerobic-aerobic biofilm exhibited an excellent ability against rise in organic loading and overall chemical oxygen demand (COD) removal efficiency of biological system was more than 93% of which 82% corresponded to the anaerobic process and 11% to the aerobic degradation. The final effluent of integrated process could meet the "water quality standards for discharge to municipal sewers" in China.

  16. Microbial community in anoxic-oxic-settling-anaerobic sludge reduction process revealed by 454 pyrosequencing analysis.

    Science.gov (United States)

    Ning, Xinqiang; Qiao, Wenwen; Zhang, Lei; Gao, Xu

    2014-12-01

    Modification of the anoxic-oxic (AO) process by inserting a sludge holding tank (SHT) into the sludge return line forms an anoxic-oxic-settling-anaerobic (A+OSA) process that can achieve a 48.98% sludge reduction rate. The 454 pyrosequencing method was used to obtain the microbial communities of the AO and A+OSA processes. Results showed that the microbial community structures of the 2 processes were different as a result of the SHT insertion. Bacteria assigned to the phyla Proteobacteria and Bacteroidetes commonly existed and dominated the microbial populations of the 2 processes. However, the relative abundance of these populations shifted in the presence of SHT. The relative abundance of Proteobacteria decreased during the A+OSA process. A specific comparison at the class level showed that Sphingobacteria was enriched in the A+OSA process. The result suggested that the fermentative bacteria Sphingobacteria may have key functions in reducing the sludge from the A+OSA process. Uncultured Nitrosomonadaceae gradually became the dominant ammonia-oxidizing bacteria, and the nitrite-oxidizing bacterium Nitrospira was enriched in the A+OSA process. Both occurrences were favorable for stabilized nitrogen removal. The known denitrifying species in the A+OSA process were similar to those in the AO process; however, their relative abundance also decreased.

  17. Prediction and quantifying parameter importance in simultaneous anaerobic sulfide and nitrate removal process using artificial neural network.

    Science.gov (United States)

    Cai, Jing; Zheng, Ping; Qaisar, Mahmood; Luo, Tao

    2015-06-01

    The present investigation deals with the prediction of the performance of simultaneous anaerobic sulfide and nitrate removal in an upflow anaerobic sludge bed (UASB) reactor through an artificial neural network (ANN). Influent sulfide concentration, influent nitrate concentration, S/N mole ratio, pH, and hydraulic retention time (HRT) for 144 days' steady-state condition were the inputs of the model; whereas output parameters were sulfide removal percentage, nitrate removal percentage, sulfate production percentage, and nitrogen production percentage. The prediction performance was evaluated by calculating root mean square error (RMSE), mean absolute error (MAE), mean absolute relative error (MARE), and determination coefficient (R (2)) values. Generally, the ANN model exhibited good prediction of the simultaneous sulfide and nitrate removal process. The effect of five input parameters to the performance of the reactor was quantified and compared using the connection weights method, Garson's algorithm method, and partial derivatives (PaD) method. The results showed that HRT markedly affects the performance of the reactor.

  18. Inhibitory effect of ammonia nitrogen on specific methanogenic activity of anaerobic granular sludge

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A series of batch experiments were conducted in 125 mL serum bottles to assess the toxicity of different concentrations of ammonia nitrogen to the specific methanogenic activity of anaerobic granular sludge from upflow anaerobic sludge bed(UASB) and expanded granular sludge bed(EGSB) reactors. The effects of pH value and temperature on toxicity of ammonia nitrogen to anaerobes were investigated. The results show that the specific methanogenic activity of anaerobic granular sludge suffers inhibition from ammonia nitrogen, the concentrations of ammonia nitrogen that produce 50% inhibition of specific methanogenic activity for sludge from UASB and EGSB reactor are 2.35 and 2.75 g/L, respectively. Hydrogen utilizing methanogens suffers less inhibition from ammonia nitrogen than that of acetate utilizing methanogens. Hydrogen-producing acetogens that utilize propionate and butyrate as substrates suffer serious inhibition from ammonia nitrogen. The toxicity of ammonia nitrogen to anaerobic granular sludge enhances when pH value and temperature increase. Anaerobic granular sludge can bear higher concentrations of ammonia nitrogen after being acclimated by ammonia nitrogen for 7 d.

  19. Succession of microbial community and enhanced mechanism of a ZVI-based anaerobic granular sludge process treating chloronitrobenzenes wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Liang, E-mail: felix79cn@hotmail.com [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058 (China); Jin, Jie [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Lin, Haizhuan [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Wenzhou Environmental Protection Design Scientific Institute, Wenzhou 325000 (China); Gao, Kaituo [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Xu, Xiangyang, E-mail: xuxy@zju.edu.cn [Department of Environmental Engineering, Zhejiang University, Hangzhou 310058 (China); Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058 (China)

    2015-03-21

    Highlights: • The combined ZVI–UASB process was established for the degradation of chloronitrobenzenes. • There were the better shock resistance and buffering capacity for anaerobic acidification in the combined process. • Novel ZVI-based anaerobic granular sludge (ZVI–AGS) was successfully developed. • Adaptive shift of microbial community was significant in ZVI-based anaerobic granular sludge system. - Abstract: The combined zero-valent iron (ZVI) and upflow anaerobic sludge blanket (UASB) process is established for the treatment of chloronitrobenzenes (ClNBs) wastewater, and the succession of microbial community and its enhanced mechanism are investigated in the study. Results showed that compared with the control UASB (R1), the stable COD removal, ClNBs transformation, and dechlorination occurred in the combined system (R2) when operated at influent COD and 3,4-Dichloronitrobenzene (3,4-DClNB) loading rates of 4200–7700 g m{sup −3} d{sup −1} and 6.0–70.0 g m{sup −3} d{sup −1}, and R2 had the better shock resistance and buffering capacity for the anaerobic acidification. The dechlorination for the intermediate products of p-chloroanaline (p-ClAn) to analine (AN) occurred in R2 reactor after 45 days, whereas it did not occur in R1 after a long-term operation. The novel ZVI-based anaerobic granular sludge (ZVI–AGS) was successfully developed in the combined system, and higher microbial activities including ClNB transformation and H{sub 2}/CH{sub 4} production were achieved simultaneously. The dominant bacteria were closely related to the groups of Megasphaera, Chloroflexi, and Clostridium, and the majority of archaea were correlated with the groups of Methanosarcinalesarchaeon, Methanosaetaconcilii, and Methanothrixsoehngenii, which are capable of reductively dechlorinating PCB, HCB, and TCE in anaerobic niche and EPS secretion.

  20. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  1. Anaerobic-aerobic small scale on-site wastewater treatment process. Kenkiter dot koki shori hoshiki jokaso

    Energy Technology Data Exchange (ETDEWEB)

    Inamori, Y. (National Institute for Environmental Studies, Tsukuba (Japan))

    1991-01-05

    As a part of the developmental project of advanced domestic wastewater treatment facilities, the following three types of small scale on-site anaerobic-aerobic wastewater treatment processes with removal functions of both BOD and nutritive salts were developed with targets of 10mg/l in BOD, 10mg/l in T-N and 1mg/l or less in T-P: an anaerobic-aerobic bio-filter treatment process with the adjustment function of hydraulic loading (A), an anaerobic-aerobic immobilized microorganisms packed fluidized bed-biofilm process (B) and a circulated anaerobic-aerobic fixed bed process (C). As the results of demonstration tests of each process using real wastewater, each process could achieve nearly the desired end, and the A process was superior in removal functions of organic substances, nitrogen and phosphorus. The C process was superior in stable removal functions of BOD and nitrogen as well as its easy production and low cost. 7 refs., 7 figs., 1 tab.

  2. ANAEROBIC DIGESTION MODEL ANALYSIS OF THE FERMENTATION PROCESS IN PSYCHROPHILIC AND MESOPHILIC CHAMBER IN ACCORDANCE WITH THE AMOUNT OF BIOGAS SOURCED

    OpenAIRE

    Dariusz Zdebik; Marcin Głodniok; Paweł Zawartka

    2015-01-01

    The paper presents problems concerning the modelling of anaerobic sludge stabilization, with the additional substrate (waste transported, dairy butchery sewage) in psychrophilic fermentation conditions in the range 10–20 °C and mesophilic at 35 °C. Simulation test was conducted in the two digesters. Results of the study allowed to evaluate the effectiveness of conducting these processes in separate chambers, i.e. the psychrophilic and mesophilic chamber. During the simulations, terms of obtai...

  3. Hydrogen and methane production from condensed molasses fermentation soluble by a two-stage anaerobic process

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chiu-Yue; Liang, You-Chyuan; Lay, Chyi-How [Feng Chia Univ., Taichung, Taiwan (China). Dept. of Environmental Engineering and Science; Chen, Chin-Chao [Chungchou Institute of Technology, Taiwan (China). Environmental Resources Lab.; Chang, Feng-Yuan [Feng Chia Univ., Taichung, Taiwan (China). Research Center for Energy and Resources

    2010-07-01

    The treatment of condensed molasses fermentation soluble (CMS) is a troublesome problem for glutamate manufacturing factory. However, CMS contains high carbohydrate and nutrient contents and is an attractive and commercially potential feedstock for bioenergy production. The aim of this paper is to produce hydrogen and methane by two-stage anaerobic fermentation process. The fermentative hydrogen production from CMS was conducted in a continuously-stirred tank bioreactor (working volume 4 L) which was operated at a hydraulic retention time (HRT) of 8 h, organic loading rate (OLR) of 120 kg COD/m{sup 3}-d, temperature of 35 C, pH 5.5 and sewage sludge as seed. The anaerobic methane production was conducted in an up-flow bioreactor (working volume 11 L) which was operated at a HRT of 24 -60 hrs, OLR of 4.0-10 kg COD/m{sup 3}-d, temperature of 35 C, pH 7.0 with using anaerobic granule sludge from fructose manufacturing factory as the seed and the effluent from hydrogen production process as the substrate. These two reactors have been operated successfully for more than 400 days. The steady-state hydrogen content, hydrogen production rate and hydrogen production yield in the hydrogen fermentation system were 37%, 169 mmol-H{sub 2}/L-d and 93 mmol-H{sub 2}/g carbohydrate{sub removed}, respectively. In the methane fermentation system, the peak methane content and methane production rate were 66.5 and 86.8 mmol-CH{sub 4}/L-d with methane production yield of 189.3 mmol-CH{sub 4}/g COD{sub removed} at an OLR 10 kg/m{sup 3}-d. The energy production rate was used to elucidate the energy efficiency for this two-stage process. The total energy production rate of 133.3 kJ/L/d was obtained with 5.5 kJ/L/d from hydrogen fermentation and 127.8 kJ/L/d from methane fermentation. (orig.)

  4. Nutrient recovery and improvement of anaerobic digestion process by low grade magnesium oxide application

    OpenAIRE

    Romero Güiza, Maycoll Stiven

    2015-01-01

    Anaerobic digestion is a worldwide technology to treat organic waste streams, primarily due to its capacity to produce methane as renewable energy. However, there is an increasing interest on nutrient recovery (N and P), which from both environmental and economic reasons have been identified as key feature in anaerobic digestion plants. Controlled struvite formation has been attracting increasing attention as a near mature technology to recover nutrients from anaerobic digestion. However, str...

  5. Dynamical model development and parameter identification for an anaerobic wastewater treatment process.

    Science.gov (United States)

    Bernard, O; Hadj-Sadok, Z; Dochain, D; Genovesi, A; Steyer, J P

    2001-11-20

    This paper deals with the development and the parameter identification of an anaerobic digestion process model. A two-step (acidogenesis-methanization) mass-balance model has been considered. The model incorporates electrochemical equilibria in order to include the alkalinity, which has to play a central role in the related monitoring and control strategy of a treatment plant. The identification is based on a set of dynamical experiments designed to cover a wide spectrum of operating conditions that are likely to take place in the practical operation of the plant. A step by step identification procedure to estimate the model parameters is presented. The results of 70 days of experiments in a 1-m(3) fermenter are then used to validate the model.

  6. EFFECT OF PLIOMETRIC TRAINING ON ANAEROBIC PERFORMANCE IN YOUNG BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    İsa SAĞIROĞLU

    2012-12-01

    Full Text Available The purpose of this study was to determine the effects of plyometric training in two different training frequencies between the competition seasons on vertical jump performance, anaerobic capability. Male basketball players aged 15-17 participated in this study. A total of 18 basketball players were divided into three groups as unbiased and in equal number (n=6; two experimental and one control group. One of these groups applied the drop jump plyometric exercise following the basketball training routine once a week while the other two groups did it three times a week, and, then, the training was completed with a stretching exercise. The study of the control group was completed with a stretching exercise after the routine. The training took eight weeks. Some measurements were taken before and after the eight weeks of the training session. Anaerobic power and capacity was recorded by the Wingate anaerobic test. Statistical comparisons among the three groups in this study were calculated by taking mean values of dependent variables, and Mann-Whitney U test, and Wilcoxon signed rank test was used for significance effects of dependent variables. Significance level was determined as p =5 . At the end of the training, it was observed that the values of the anaerobic power and capacity values of plyometric exercise groups showed statistically significant improvements. A statistically significant increase in the values of anaerobic power and capacity was provided for the experimental group doing the plyometric exercise once a week compared with the control group.

  7. Liquefaction and methanization of solid and liquid coffee wastes by two phase anaerobic digestion process.

    Science.gov (United States)

    Houbron, E; Larrinaga, A; Rustrian, E

    2003-01-01

    This study attempted to investigate the feasibility of volatile fatty acid (VFA) production from coffee pulp hydrolyse, and further to determine the potential of methanization of both the pre-acidified effluent and the coffee wastewater. The experiments were carried out in 2 completely mixed reactors, each one with a working volume of 4 litres. Coffee pulp was used as substrate in the acidogenic reactor and different mixtures of pulper and wash-water and pre-acidified effluent in the methanogenic one. The acidogenic and methanogenic reactors were operated at an organic loading rate of 5 COD g x l(-1) x d(-1) and 0.5 COD g x l(-1) x d(-1). The total, soluble and VFA's effluent COD concentrations of the acidogenic reactor present average values of 57.75, 17.00 and 13.92 g x l(-1) respectively. Under these experimental conditions, 23% (COD based) of coffee pulp was hydrolysed with a rate of 1.32 gCOD x l(-1) x d(-1) and the soluble fraction was transformed to VFA's with an acidification efficiency of 82%. Total VFA's concentration reached a value of 13.9 gCOD x l(-1), and acetate, propionate, butyrate and valerate represented 52%, 28%, 9% and 11% respectively of the liquid phase COD. In the methanogenic reactor, COD removal and methanization of fresh coffee wastewater, pre-acidified effluent and both combined occur with an efficiency of 85% to 95% respectively, with a characteristic biogas composition of 80% CH4 and 20% CO2. These results show that a humid coffee "Beneficio" processing daily 23 tons of cherry coffee (fresh fruit), equipped with a two stage anaerobic digestion process could generate at least 1,886 CH4 m3 x d(-1). This represents an increase in methane production by a factor 3 to 5 compared to a "Beneficio" using anaerobic digestion only for the treatment of its wastewater.

  8. [Effect of butachlor on CH4 emission and anaerobes in paddy soil].

    Science.gov (United States)

    Zhao, Y; Mei, Q; Chen, M; Min, H

    1997-12-01

    Effects of butachlor on CH4 emission and the count of anaerobes in paddy soil or in the media were studied. The results obtained showed that CH4 emission and growth of methanogens would be greatly affected at field rates of butachlor within 2 weeks, but this adverse effects would disappear as time went on. CH4 emission and methanogenic activities would be retarded by butachlor in media for longer time. The amount of butachlor available to act upon anaerobes depended on application rate and method of application.

  9. Anaerobic Slurry Co-Digestion of Poultry Manure and Straw: Effect of Organic Loading and Temperature

    Directory of Open Access Journals (Sweden)

    Azadeh Babaee

    2013-07-01

    Full Text Available In order to obtain basic design criteria for anaerobic digestion of a mixture of poultry manure and wheat straw, the effects of different temperatures and organic loading rates on the biogas yield and methane contents were evaluated. Since poultry manure is a poor substrate, in term of the availability of the nutrients, external supplementation of carbon has to be regularly performed, in order to achieve a stable and efficient process. The complete-mix, pilot-scale digester with working volume of 70 L was used. The digestion operated at 25[degree sign]C, 30[degree sign]C and 35[degree sign]C with organic loading rates of 1.0, 2.0, 2.5, 3.0, 3.5 and 4.0 kg Volatile solid/m3d and a HRT of 15 days. At a temperature of 35[degree sign]C, the methane yield was increased by 43% compared to 25[degree sign]C. Anaerobic co-digestion appeared feasible with a loading rate of 3.0 kg VS/m3d at 35[degree sign]C. At this state, the specific methane yield was calculated about 0.12 m3/kg VS with a methane content of 53--70.2% in the biogas. The volatile solid (VS removal was 72%. As a result of volatile fatty acid accumulation and decrease in pH, when the loading rate was less than 1 or greater than 4 kg VS/m3d, the process was inhibited or overloaded, respectively. Both the lower and higher loading rates resulted in a decline in the methane yield.

  10. Strong Pasteur effect in rabbit corneal endothelium preserves fluid transport under anaerobic conditions.

    Science.gov (United States)

    Riley, M V; Winkler, B S

    1990-07-01

    1. The hydration and transparency of the mammalian cornea are maintained by a metabolically dependent fluid transport system located in the endothelial cell layer. The purpose of the study was to determine whether this pump activity is dependent upon aerobic or anaerobic metabolism. 2. The ability of the cornea, superfused in vitro with a bicarbonate-Ringer solution containing glucose and adenosine, to maintain normal hydration (thickness) when respiration is inhibited has been examined in intact and de-epithelialized preparations and correlated with glycolytic activity and cellular concentrations of ATP. 3. In respiring intact and de-epithelialized corneas thickness was maintained for periods up to 5 h during superfusion with the control Ringer solution. 4. KCN (10(-3) M) or antimycin A (10(-6) M) caused the intact cornea to swell at 15 +/- 3 microns h-1, whereas the de-epithelialized tissue maintained normal thickness under these conditions. This swelling of the intact tissue appears to be due to the osmotic effect of increased epithelial lactate production under anaerobic conditions. 5. Pre-swollen de-epithelialized corneas deturgesced fully to original thickness at a rate of 43 +/- 7 microns h-1 under aerobic conditions, but with KCN or antimycin they deturgesced at only 65% of that rate and generally failed to return to their original thickness. 6. Ouabain (10(-4) M) caused de-epithelialized corneas to swell in the presence of KCN or antimycin, as it did under aerobic conditions, showing that maintenance of hydration or deturgescence are pump-dependent processes under both conditions. 7. Lactate production was markedly stimulated by KCN or antimycin in intact and de-epithelialized preparations, but not in the stroma alone. The magnitude of the Pasteur effect was calculated to be 5-fold in the endothelium and 2.5-fold in the epithelium. Ouabain inhibited anaerobic lactate production in the endothelium by 50%. 8. ATP content of the epithelium following 5 h

  11. State of the art of R and D in the anaerobic digestion process of municipal solid waste in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, F.; Traverso, P.G.; Mata-Alvarez, J.; Clancy, J.; Zaror, C.

    1988-01-01

    The state of the art of R and D in the field of anaerobic digestion of municipal solid waste in Europe is reviewed. A comparison is made of the quality and quantity of refuse produced in different European countries using data available in recent literature. The conclusion to be drawn from this analysis is that in programmes involving demonstration and full scale plants it is necessary to carry out more detailed studies of the process and its control, as well as carrying out further work on the microbiological aspects of anaerobic digestion of municipal solid waste.

  12. Study on biological phosphorus removal process by Acinetobacter lwoffi: possibility to by-pass the anaerobic phase

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, R.; Lodi, A.; Rovatti, M. [Institute of Chemical and Process Engineering ``G.B. Bonino``, University of Genoa (Italy)

    1998-03-01

    An Acinetobacter lwoffi culture has been submitted to anaerobic/aerobic conditions in a Sequencing Batch Reactor (SBR) in order to study the ability of this strain in biological phosphorus removal process. Even by feeding a pure sodium acetate substrate, no phosphorus release has been detected during anaerobiosis, while phosphorus uptake beyond metabolic needs has been recorded during the aerobic phase; the anaerobic phase seems to have no influence on the enhanced biological phosphorus removal mechanisms. Hence aerobic batch tests have been carried out in order to verify the ability of Acinetobacter lwoffi to remove phosphorus by ``luxury uptake`` and ``overplus accumulation`` without anaerobic stress. Obtained results revealed a phosphorus removal efficiency of 75-80%. (orig.) With 5 figs., 3 tabs., 18 refs.

  13. A new multiple-stage electrocoagulation process on anaerobic digestion effluent to simultaneously reclaim water and clean up biogas.

    Science.gov (United States)

    Liu, Zhiguo; Stromberg, David; Liu, Xuming; Liao, Wei; Liu, Yan

    2015-03-21

    A new multiple-stage treatment process was developed via integrating electrocoagulation with biogas pumping to simultaneously reclaim anaerobic digestion effluent and clean up biogas. The 1st stage of electrocoagulation treatment under the preferred reaction condition led to removal efficiencies of 30%, 81%, 37% and >99.9% for total solids, chemical oxygen demand, total nitrogen and total phosphorus, respectively. Raw biogas was then used as a reactant and pumped into the effluent to simultaneously neutralize pH of the effluent and remove H2S in the biogas. The 2nd stage of electrocoagulation treatment on the neutralized effluent showed that under the selected reaction condition, additional 60% and 10% of turbidity and chemical oxygen demand were further removed. The study concluded a dual-purpose approach for the first time to synergistically combine biogas purification and water reclamation for anaerobic digestion system, which well addresses the downstream challenges of anaerobic digestion technology.

  14. The Effect of Anaerobic and Aerobic Fish Sludge Supernatant on Hydroponic Lettuce

    Directory of Open Access Journals (Sweden)

    Simon Goddek

    2016-06-01

    Full Text Available The mobilization of nutrients from fish sludge (i.e., feces and uneaten feed plays a key role in optimizing the resource utilization and thus in improving the sustainability of aquaponic systems. While several studies have documented the aerobic and anaerobic digestion performance of aquaculture sludge, the impact of the digestate on plant growth has yet to be understood. The present study examines the impact of either an aerobic or an anaerobic digestion effluent on lettuce plant growth, by enriching a mixture of aquaculture and tap water with supernatants from both aerobic and anaerobic batch reactors. The lettuce plants grown in the hydroponic system supplied with supernatant from an anaerobic reactor had significantly better performance with respect to weight gain than both, those in the system where supernatant from the aerobic reactor was added, as well as the control system. It can be hypothesized that this effect was caused by the presence of NH4+ as well as dissolved organic matter, plant growth promoting rhizobacteria and fungi, and humic acid, which are predominantly present in anaerobic effluents. This study should therefore be of value to researchers and practitioners wishing to further develop sludge remineralization in aquaponic systems.

  15. Enhancing anaerobic digestion of waste activated sludge by pretreatment: effect of volatile to total solids.

    Science.gov (United States)

    Wang, Xiao; Duan, Xu; Chen, Jianguang; Fang, Kuo; Feng, Leiyu; Yan, Yuanyuan; Zhou, Qi

    2016-01-01

    In this study the effect of volatile to total solids (VS/TS) on anaerobic digestion of waste activated sludge (WAS) pretreated by alkaline, thermal and thermal-alkaline strategies was studied. Experimental results showed that the production of methane from sludge was increased with VS/TS. When anaerobic digesters were fed with sludge pretreated by the thermal-alkaline method, the average methane yield was improved from 2.8 L/d at VS/TS 0.35 to 4.7 L/d at VS/TS 0.56. Also, the efficiency of VS reduction during sludge anaerobic digestion varied between 18.9% and 45.6%, and increased gradually with VS/TS. Mechanism investigation of VS/TS on WAS anaerobic digestion suggested that the general activities of anaerobic microorganisms, activities of key enzymes related to sludge hydrolysis, acidification and methanogenesis, and the ratio of Archaea to Bacteria were all increased with VS/TS, showing good agreement with methane production.

  16. High-rate two-phase process for the anaerobic degradation of cellulose, employing rumen microorganisms for an efficient acidogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Gijzen, H.J.; Zwart, K.B.; Verhagen, F.J.M.; Vogels, G.D.

    1988-04-05

    A novel two-stage anaerobic process for the microbial conversion of cellulose into biogas has been developed. In the first phase, a mixed population of rumen bacteria and ciliates was used in the hydrolysis and fermentation of cellulose. The volatile fatty acids (VFA) produced in this acidogenic reactor were subsequently converted into biogas in a UASB-type methanogenic reactor. A stepwise increase of the loading rate from 11.9 to 25.8 g volatile solids/L reactor volume/day (g VS/L/day) did not affect the degradation efficiency in the acidogenic reactor, whereas the methanogenic reactor appeared to be overloaded at the highest loading rate. Cellulose digestion was almost complete at all loading rates applied. The two-stage anaerobic process was also tested with a closed fluid circuit. In this instance total methane production was 0.438 L CH/sub 4//g VS added, which is equivalent to 98% of the theoretical value. The application of rumen microorganisms in combination with a high-rate methane reactor is proposed as a means of efficient anaerobic degradation of cellulosic residues to methane. Because this newly developed two-phase system is based on processes and microorganisms from the ruminant, it will be referred to as Rumen Derived Anaerobic Digestion (RUDAD)-process.

  17. A novel full recycling process through two-stage anaerobic treatment of distillery wastewater for bioethanol production from cassava.

    Science.gov (United States)

    Zhang, Qing-Hua; Lu, Xin; Tang, Lei; Mao, Zhong-Gui; Zhang, Jian-Hua; Zhang, Hong-Jian; Sun, Fu-Bao

    2010-07-15

    In the present study, a novel full recycling process for bioethanol production was investigated, where three mathematical models were established to simulate the accumulation of major soluble inhibitory substances, including organic compounds, total ions, volatile fatty acids (VFAs) and colorants. These inhibitory substances in the reused water reached a relative steady state after 3-7 batches of anaerobic treatment and recycling process, which coincided with the results of mathematical models. There were no negative effects of these inhibitory substances on ethanol fermentation and the final ethanol yield, fermentation time, starch utilization ratio were very close to that of the conventional process using tap water. However, approximately 7.54% (w/w) of water was lost during each circulation, which was replenished in subsequent circulations, to assure consistent fermentation broth volume. This novel process was confirmed to have a stable operation over 13 recycles. It is concluded the stable states of the inhibitory substances in the reused water can assure this recycling process will run successfully.

  18. Effects of total ammonia nitrogen concentration on solid-state anaerobic digestion of corn stover.

    Science.gov (United States)

    Wang, Zhongjiang; Xu, Fuqing; Li, Yebo

    2013-09-01

    The inhibitive effect of total ammonia nitrogen (TAN) (including NH3 and NH4(+)) on solid-state anaerobic digestion of corn stover was investigated in batch reactors at 37°C. The highest methane yield of 107.0 L/kg VS(feed) was obtained at a TAN concentration of 2.5 g/kg (based on total weight). TAN concentrations greater than 2.5 g/kg resulted in decreased methane yields, with a 50% reduction observed at a concentration of 6.0 g/kg. Reduced reaction rates and microbial activities for hydrolysis of cellulose and methanogenesis from acetate were observed at TAN concentrations higher than 4.3 g/kg. Strong ammonia stress was indicated at butyrate concentrations higher than 300 mg/kg. Result showed that the effluent of liquid anaerobic digestion can provide enough nitrogen for solid-state anaerobic digestion of corn stover.

  19. Evidence for anaerobic ammonium oxidation process in freshwater sediments of aquaculture ponds.

    Science.gov (United States)

    Shen, Li-dong; Wu, Hong-sheng; Gao, Zhi-qiu; Ruan, Yun-jie; Xu, Xiang-hua; Li, Ji; Ma, Shi-jie; Zheng, Pei-hui

    2016-01-01

    The anaerobic ammonium oxidation (anammox) process, which can simultaneously remove ammonium and nitrite, both toxic to aquatic animals, can be very important to the aquaculture industry. Here, the presence and activity of anammox bacteria in the sediments of four different freshwater aquaculture ponds were investigated by using Illumina-based 16S rRNA gene sequencing, quantitative PCR assays and (15)N stable isotope measurements. Different genera of anammox bacteria were detected in the examined pond sediments, including Candidatus Brocadia, Candidatus Kuenenia and Candidatus Anammoxoglobus, with Candidatus Brocadia being the dominant anammox genus. Quantitative PCR of hydrazine synthase genes showed that the abundance of anammox bacteria ranged from 5.6 × 10(4) to 2.1 × 10(5) copies g(-1) sediment in the examined ponds. The potential anammox rates ranged between 3.7 and 19.4 nmol N2 g(-1) sediment day(-1), and the potential denitrification rates varied from 107.1 to 300.3 nmol N2 g(-1) sediment day(-1). The anammox process contributed 1.2-15.3% to sediment dinitrogen gas production, while the remainder would be due to denitrification. It is estimated that a total loss of 2.1-10.9 g N m(-2) per year could be attributed to the anammox process in the examined ponds, suggesting that this process could contribute to nitrogen removal in freshwater aquaculture ponds.

  20. Effect of temperature and pH on the anaerobic digestion of grass silage

    OpenAIRE

    2014-01-01

    The operating temperature and pH level in the digester during anaerobic digestion and the retention period are among the major factors that affect the rate of biogas production. Therefore, this paper evaluates the effects of temperature and pH in anaerobic digestion of grass silage. Grass silage was digested in 1000ml at different temperatures (35 ○C, 40 ○C, 45 ○C and 50 ○C) and pH (6.5, 6.8 &7.2). The digesters were shaken everyday to prevent the formation of surface crust which may prevent ...

  1. The effect of the source of microorganisms on adaptation of hydrolytic consortia dedicated to anaerobic digestion of maize silage.

    Science.gov (United States)

    Poszytek, Krzysztof; Pyzik, Adam; Sobczak, Adam; Lipinski, Leszek; Sklodowska, Aleksandra; Drewniak, Lukasz

    2017-02-17

    The main aim of this study was to evaluate the effect of the source of microorganisms on the selection of hydrolytic consortia dedicated to anaerobic digestion of maize silage. The selection process was investigated based on the analysis of changes in the hydrolytic activity and the diversity of microbial communities derived from (i) a hydrolyzer of a commercial agricultural biogas plant, (ii) cattle slurry and (iii) raw sewage sludge, during a series of 10 passages. Following the selection process, the adapted consortia were thoroughly analyzed for their ability to utilize maize silage and augmentation of anaerobic digestion communities. The results of selection of the consortia showed that every subsequent passage of each consortium leads to their adaptation to degradation of maize silage, which was manifested by the increased hydrolytic activity of the adapted consortia. Biodiversity analysis (based on the 16S rDNA amplicon sequencing) confirmed the changes microbial community of each consortium, and showed that after the last (10th) passage all microbial communities were dominated by the representatives of Lactobacillaceae, Prevotellaceae, Veillonellaceae. The results of the functional analyses showed that the adapted consortia improved the efficiency of maize silage degradation, as indicated by the increase in the concentration of glucose and volatile fatty acids (VFAs), as well as the soluble chemical oxygen demand (sCOD). Moreover, bioaugmentation of anaerobic digestion communities by the adapted hydrolytic consortia increased biogas yield by 10-29%, depending on the origin of the community. The obtained results also indicate that substrate input (not community origin) was the driving force responsible for the changes in the community structure of hydrolytic consortia dedicated to anaerobic digestion.

  2. Assessment of anti-fouling strategies for membrane coupled with upflow anaerobic sludge blanket (MUASB) process.

    Science.gov (United States)

    Tran, Thao Minh; Ye, Yun; Chen, Vicki; Stuetz, Richard; Le-Clech, Pierre

    2013-01-01

    In this novel process, domestic wastewater was filtered by a hollow-fibre membrane coupled with an upflow anaerobic sludge blanket (MUASB) bioreactor. To improve the process sustainability and decrease energy costs, the membranes were operated under low fluxes with little, or no, shear. The efficiency of anti-fouling strategies, including relaxation, backwashing and supply of low aeration and stir rates, was assessed through detailed characterization of the fouling layers. Results indicated that backwashing was more efficient than relaxation, even when the systems were operated under the same flux productivity. In terms of shear supply, stir provided a better fouling limitation strategy compared to aeration, at similar shear stress values. Physical and chemical cleaning methods were applied to recover three fouling fractions (i.e. cake, residual and irreversible) for better characterization of the fouling layers. Under the sustainable operating conditions used in this study, most of the fouling was easily reversible by simple rinsing. In addition, permanent and irreversible fouling, resulting in the need for frequent chemical cleanings and potential membrane degradation, is limited once small shear stresses are applied. These outcomes are expected to form the basis for the future assessment of trade-off between operation, maintenance and replacement costs of membrane filtration processes used in wastewater treatment.

  3. Soaking pretreatment of corn stover for bioethanol production followed by anaerobic digestion process.

    Science.gov (United States)

    Zuo, Zhuang; Tian, Shen; Chen, Zebing; Li, Jia; Yang, Xiushan

    2012-08-01

    The production of ethanol and methane from corn stover (CS) was investigated in a biorefinery process. Initially, a novel soaking pretreatment (NaOH and aqueous-ammonia) for CS was developed to remove lignin, swell the biomass, and improve enzymatic digestibility. Based on the sugar yield during enzymatic hydrolysis, the optimal pretreatment conditions were 1 % NaOH+8 % NH(4)OH, 50°C, 48 h, with a solid-to-liquid ratio 1:10. The results demonstrated that soaking pretreatment removed 63.6 % lignin while reserving most of the carbohydrates. After enzymatic hydrolysis, the yields of glucose and xylose were 78.5 % and 69.3 %, respectively. The simultaneous saccharification and fermentation of pretreated CS using Pichia stipitis resulted in an ethanol concentration of 36.1 g/L, corresponding only to 63.3 % of the theoretical maximum. In order to simplify the process and reduce the capital cost, the liquid fraction of the pretreatment was used to re-soak new CS. For methane production, the re-soaked CS and the residues of SSF were anaerobically digested for 120 days. Fifteen grams CS were converted to 1.9 g of ethanol and 1337.3 mL of methane in the entire process.

  4. Effect of ammonia on the anaerobic hydrolysis of cellulose and tributyrin

    NARCIS (Netherlands)

    Vasconcelos Fernandes, T.; Keesman, K.J.; Zeeman, G.; Lier, van J.B.

    2012-01-01

    Ammonia nitrogen is one of the most common inhibitors in the anaerobic digestion of complex wastes containing high concentrations of ammonia like animal manures, blackwater and waste oil from gastronomy. The inhibiting effect of ammonia on methanogenesis has been well established. In contrast, the k

  5. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    NARCIS (Netherlands)

    Mashad, El H.; Zeeman, G.; Loon, van W.K.P.; Bot, G.P.A.; Lettinga, G.

    2004-01-01

    The influence of temperature, 50 and 60 °C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fl

  6. Investigating Aerobic, Anaerobic Combine Technical Trainings' Effects on Performance in Tennis Players

    Science.gov (United States)

    Suna, Gürhan; Kumartasli, Mehmet

    2017-01-01

    The aim of this study is to investigate eight-week aerobic, anaerobic combine technical trainings' effects on developments of performance. 21 athletes of tennis proficiency students from Sports Sciences Department were joined to the study voluntarily. Participated in the research athletes' ages' mean was 22,2 ± 0,3 year, lengths' mean was 177,3 ±…

  7. Enhanced biological nutrient removal in modified carbon source division anaerobic anoxic oxic process with return activated sludge pre-concentration☆

    Institute of Scientific and Technical Information of China (English)

    Qin Lu; Haiyan Wu; Haoyan Li; Dianhai Yang

    2015-01-01

    A pilot-scale modified carbon source division anaerobic anoxic oxic (AAO) process with pre-concentration of returned activated sludge (RAS) was proposed in this study for the enhanced biological nutrient removal (BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60%and 50%, respectively, with an inner recycling ratio of 100%under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L−1 with a removal efficiency of 63%and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.

  8. Effect of the chlortetracycline addition method on methane production from the anaerobic digestion of swine wastewater.

    Science.gov (United States)

    Huang, Lu; Wen, Xin; Wang, Yan; Zou, Yongde; Ma, Baohua; Liao, Xindi; Liang, Juanboo; Wu, Yinbao

    2014-10-01

    Effects of antibiotic residues on methane production in anaerobic digestion are commonly studied using the following two antibiotic addition methods: (1) adding manure from animals that consume a diet containing antibiotics, and (2) adding antibiotic-free animal manure spiked with antibiotics. This study used chlortetracycline (CTC) as a model antibiotic to examine the effects of the antibiotic addition method on methane production in anaerobic digestion under two different swine wastewater concentrations (0.55 and 0.22mg CTC/g dry manure). The results showed that CTC degradation rate in which manure was directly added at 0.55mg CTC/g (HSPIKE treatment) was lower than the control values and the rest of the treatment groups. Methane production from the HSPIKE treatment was reduced (pmethane production under different antibiotic addition methods might be explained by the microbial activity and the concentrations of antibiotic intermediate products and metabolites. Because the primary entry route of veterinary antibiotics into an anaerobic digester is by contaminated animal manure, the most appropriate method for studying antibiotic residue effects on methane production may be using manure from animals that are given a particular antibiotic, rather than adding the antibiotic directly to the anaerobic digester.

  9. Effects of psychological priming, video, and music on anaerobic exercise performance.

    Science.gov (United States)

    Loizou, G; Karageorghis, C I

    2015-12-01

    Peak performance videos accompanied by music can help athletes to optimize their pre-competition mindset and are often used. Priming techniques can be incorporated into such videos to influence athletes' motivational state. There has been limited empirical work investigating the combined effects of such stimuli on anaerobic performance. The present study examined the psychological and psychophysiological effects of video, music, and priming when used as a pre-performance intervention for an anaerobic endurance task. Psychological measures included the main axes of the circumplex model of affect and liking scores taken pre-task, and the Exercise-induced Feeling Inventory, which was administered post-task. Physiological measures comprised heart rate variability and heart rate recorded pre-task. Fifteen males (age = 26.3 ± 2.8 years) were exposed to four conditions prior to performing the Wingate Anaerobic Test: music-only, video and music, video with music and motivational primes, and a no-video/no-music control. Results indicate that the combined video, music, and primes condition was the most effective in terms of influencing participants' pre-task affect and subsequent anaerobic performance; this was followed by the music-only condition. The findings indicate the utility of such stimuli as a pre-performance technique to enhance athletes' or exercisers' psychological states.

  10. Reviewing the anaerobic digestion and co-digestion process of food waste from the perspectives on biogas production performance and environmental impacts.

    Science.gov (United States)

    Chiu, Sam L H; Lo, Irene M C

    2016-12-01

    In this paper, factors that affect biogas production in the anaerobic digestion (AD) and anaerobic co-digestion (coAD) processes of food waste are reviewed with the aim to improve biogas production performance. These factors include the composition of substrates in food waste coAD as well as pre-treatment methods and anaerobic reactor system designs in both food waste AD and coAD. Due to the characteristics of the substrates used, the biogas production performance varies as different effects are exhibited on nutrient balance, inhibitory substance dilution, and trace metal element supplement. Various types of pre-treatment methods such as mechanical, chemical, thermal, and biological methods are discussed to improve the rate-limiting hydrolytic step in the digestion processes. The operation parameters of a reactor system are also reviewed with consideration of the characteristics of the substrates. Since the environmental awareness and concerns for waste management systems have been increasing, this paper also addresses possible environmental impacts of AD and coAD in food waste treatment and recommends feasible methods to reduce the impacts. In addition, uncertainties in the life cycle assessment (LCA) studies are also discussed.

  11. Techno-economic evaluation of stillage treatment with anaerobic digestion in a softwood-to-ethanol process

    Directory of Open Access Journals (Sweden)

    Barta Zsolt

    2010-09-01

    Full Text Available Abstract Background Replacing the energy-intensive evaporation of stillage by anaerobic digestion is one way of decreasing the energy demand of the lignocellulosic biomass to the ethanol process. The biogas can be upgraded and sold as transportation fuel, injected directly into the gas grid or be incinerated on-site for combined heat and power generation. A techno-economic evaluation of the spruce-to-ethanol process, based on SO2-catalysed steam pretreatment followed by simultaneous saccharification and fermentation, has been performed using the commercial flow-sheeting program Aspen Plus™. Various process configurations of anaerobic digestion of the stillage, with different combinations of co-products, have been evaluated in terms of energy efficiency and ethanol production cost versus the reference case of evaporation. Results Anaerobic digestion of the stillage showed a significantly higher overall energy efficiency (87-92%, based on the lower heating values, than the reference case (81%. Although the amount of ethanol produced was the same in all scenarios, the production cost varied between 4.00 and 5.27 Swedish kronor per litre (0.38-0.50 euro/L, including the reference case. Conclusions Higher energy efficiency options did not necessarily result in lower ethanol production costs. Anaerobic digestion of the stillage with biogas upgrading was demonstrated to be a favourable option for both energy efficiency and ethanol production cost. The difference in the production cost of ethanol between using the whole stillage or only the liquid fraction in anaerobic digestion was negligible for the combination of co-products including upgraded biogas, electricity and district heat.

  12. Anoxic phosphorus removal in a pilot scale anaerobic-anoxic oxidation ditch process

    Institute of Scientific and Technical Information of China (English)

    Hongxun HOU; Shuying WANG; Yongzhen PENG; Zhiguo YUAN; Fangfang YIN; Wang GAN

    2009-01-01

    The anaerobic-anoxic oxidation ditch (A2/O OD) process is popularly used to eliminate nutrients from domestic wastewater. In order to identify the existence of denitrifying phosphorus removing bacteria (DPB), evalu-ate the contribution of DPB to biological nutrient removal,and enhance the denitrifying phosphorus removal in the A2/O OD process, a pilot-scale A2/O OD plant (375 L)was conducted. At the same time batch tests using sequence batch reactors (12 L and 4 L) were operated to reveal the significance of anoxic phosphorus removal. The results indicated that: The average removal efficiency of COD, NH4+, pO3-4, and TN were 88.2%, 92.6%, 87.8%,and 73.1%, respectively, when the steady state of the pilotscale A2/O OD plant was reached during 31-73d,demonstrating a good denitrifying phosphorus removal performance. Phosphorus uptake took place in the anoxic zone by poly-phosphorus accumulating organisms NO2- could be used as electron receptors in denitrifying phosphorus removal, and the phosphorus uptake rate with NO2- as the electron receptor was higher than that with NO3- when the initial concentration of either NO2- or NO3 was 40 mg/L.

  13. Critical assessment of anaerobic processes for continuous biohydrogen production from organic wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Show, Kuan-Yeow [Faculty of Engineering and Green Technology, University Tunku Abdul Rahman, Jalan University, Bandar Barat, 31900 Kampar, Perak (Malaysia); Zhang, Zhen-Peng [Beijing Enterprises Water Group Limited, BLK 25, No. 3 Minzhuang Road, Beijing 100195 (China); Tay, Joo-Hwa [School of Civil and Environmental Engineering, Nanyang Technological University, Nanyang Avenue (Singapore); Liang, David Tee [Institute of Environmental Science and Engineering, Nanyang Technological University (Singapore); Lee, Duu-Jong [Department of Chemical Engineering, National Taiwan University, Taipei (China); Ren, Nanqi; Wang, Aijie [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China)

    2010-12-15

    Production of biohydrogen using dark fermentation has received much attention owing to the fact that hydrogen can be generated from renewable organics including waste materials. The key to successful application of anaerobic fermentation is to uncouple the liquid retention time and the biomass retention time in the reactor system. Various reactor designs based on biomass retention within the reactor system have been developed. This paper presents our research work on bioreactor designs and operation for biohydrogen production. Comparisons between immobilized-cell systems and suspended-cell systems based on biomass growth in the forms of granule, biofilm and flocs were made. Reactor configurations including column- and tank-based reactors were also assessed. Experimental results indicated that formation of granules or biofilms substantially enhanced biomass retention which was found to be proportional to the hydrogen production rate. Rapid hydrogen-producing culture growth and high organic loading rate might limit the application of biofilm biohydrogen production, since excessive growth of fermentative biomass would result in washout of support carrier. It follows that column-based granular sludge process is a preferred choice of process for continuous biohydrogen production from organic wastewater, indicating maximum hydrogen yield of 1.7 mol-H{sub 2}/mol-glucose and hydrogen production rate of 6.8 L-H{sub 2}/L-reactor h. (author)

  14. Liquefaction and methanization of solid and liquid coffee wastes by two phase anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Houbron, E.; Rustrian, E. [Universidad Veracruzana, Orizaba, Ver. (Mexico). Facultad de Ciencias Quimicas; Larrinaga, A. [Instituto tecnologico de Orizaba, Ver. (Mexico)

    2003-07-01

    This study attempted to investigate the feasibility of volatile fatty acid (VFA) production from coffee pulp hydrolyse, and further to determine the potential of methanization of both the pre-acidified effluent and the coffee wastewater. The experiments were carried out in 2 completely mixed reactors, each one with working volume of 4 litres. Coffee pulp was used as substrate in the acidogenic reactor and different mixtures of pulper and wash-water and pre-acidified effluent in the methanogenic one. The acidogenic and methanogenic reactors were operated at an organic loading rate of 5 COD g.l{sup -1}.d{sup -1} and 0.5 COD g.l{sup -1}.d{sup -1}. The total, soluble and VFA's effluent COD concentrations of the acidogenic reactor present average values of 57.75, 17.00 and 13.92 g.l{sup -1} respectively. Under these experimental conditions, 23% (COD based) of coffee pulp was hydrolysed with a rate of 1.32 gCOD.l{sup -1}.d{sup -1} and the soluble fraction was transformed to VFA's with an acidification efficiency of 82%. Total VFA's concentration reached a value of 13.9 gCOD.l{sup -1}, and acetate, propionate, butyrate and valerate represented 52%, 28%, 9% and 11% respectively of the liquid phase COD. In the methanogenic reactor, COD removal and methanization of fresh coffee wastewater, pre-acidified effluent and both combined occur with an efficiency of 85% to 95% respectively, with a characteristic biogas composition of 80% CH{sub 4} and 20% CO{sub 2}. These results show that a humid coffee 'Beneficio' processing daily 23 tons of cherry coffee (fresh fruit), equipped with a two stage anaerobic digestion process could generate at least 1,886 CH{sub 4} m{sup 3}.d{sup -1}. This represents an increase in methane production by a factor 3 to 5 compared to a 'Beneficio' using anaerobic digestion only for the treatment of its wastewater. (author)

  15. Effect of ultrasonic pretreatment on anaerobic digestion and its sludge dewaterability

    Institute of Scientific and Technical Information of China (English)

    Huacheng Xu; Pinjing He; Guanghui Yu; Liming Shao

    2011-01-01

    To investigate the effect of ultrasonic pretreatment on anaerobic digestion and sludge dewaterability and further to probe into the influencing factors on sludge dewaterability,sludge flocs were stratified into four fractions:(1) slime; (2) loosely bound extracellular polymeric substances (LB-EPS); (3) tightly bound EPS (TB-EPS); and (4) EPS-free pellets.The results showed that ultrasonic pretreatment increased the anaerobic digestion efficiency by 7%-8%.Anaerobic digestion without ultrasonic pretreatment deteriorated the sludge dewaterability,with the capillary suction time (CST) increased from 1.42 to 47.3 (sec.L)/g-TSS.The application of ultrasonic pretreatment firstly deteriorated the sludge dewaterability (normalized CST increased to 44.4 (sec.L)/g-TSS),while subsequent anaerobic digestion offset this effect and ultimately decreased the normalized CST to 23.2 (sec.L)/g-TSS.The dewaterability of unsonicated sludge correlated with protein (p = 0.003) and polysaccharide (p = 0.004) concentrations in the slime fraction,while that of sonicated sludge correlated with protein concentrations in the slime and LB-EPS fractions (p < 0.05).Fluorescent excitationemission matrix analysis showed that the fluorescence matters in the LB-EPS fraction significantly correlated with sludge dewaterability during anarobic digestion.

  16. Effect of thermal hydrolysis and ultrasounds pretreatments on foaming in anaerobic digesters.

    Science.gov (United States)

    Alfaro, N; Cano, R; Fdz-Polanco, F

    2014-10-01

    Foam appears regularly in anaerobic digesters producing operational and safety problems. In this research, based on the operational observation at semi-industrial pilot scale where sludge pretreatment mitigated foaming in anaerobic digesters, this study aimed at evaluating any potential relationship between foaming tools applied to activated sludge at lab-scale (foam potential, foam stability and Microthrix parvicella abundance) and the experimental behavior observed in pilot scale and full-scale anaerobic digesters. The potential of thermal hydrolysis and ultrasounds for reducing foaming capacity was also evaluated. Filamentous bacteria abundance was directly linked to foaming capacity in anaerobic processes. A maximum reduction of M.parvicella abundance (from 5 to 2) was reached using thermal hydrolysis with steam explosion at 170°C and ultrasounds at 66.7kWh/m(3), showing both good anti-foaming properties. On the other hand, foam potential and stability determinations showed a lack of consistency with the bacteria abundance results and experimental evidences.

  17. The anaerobic digestion process capability to produce biostimulant: the case study of the dissolved organic matter (DOM) vs. auxin-like property.

    Science.gov (United States)

    Scaglia, Barbara; Pognani, Michele; Adani, Fabrizio

    2017-07-01

    Biostimulants improve plant growth by stimulating nutrient uptake and efficiency, improving tolerance to abiotic stress and raising crop quality. Biostimulants are currently only recognised in five categories. However, the recent interest in this sector has led to the identification of some new ones. The aim of this work was to study the auxin-like activity of digestate dissolved organic matter (DOM) obtained from full scale anaerobic digester plants. All DOMs had biostimulant capacity comparable with humic acid and amino acids. The auxin-like activities depended mainly on the hydrophobic DOM fractions for the presence of auxin-active and other auxin-like molecules. Significant correlations were found for the auxin-effect in relation to auxin-active molecules and fatty acids responsible for most of the auxin-like effects (67% of the total importance in giving auxin-like activity) while a minor or null contribution was attributable to the carboxylic acids and aminoacid categories. Therefore, the anaerobic digestion process seems to be a useful biotechnology to produce biostimulants. Basing on these first results, the expanding anaerobic digestion sector could become important for the production of new biostimulant classes to meet the agricultural sector's new requirements and saving on raw materials.

  18. Developing a nutrient recovery process for recovering nutrients in anaerobic digestate in low income countries

    OpenAIRE

    Rose, Christopher

    2015-01-01

    It is estimated that 2.7 billion people worldwide are served by on-site sanitation facilities that require faecal sludge management. Anaerobic digestion is a treatment mechanism that can provide faecal sludge management, methane production and an effluent digestate rich in nutrients. However, there is a paucity of information regarding the composition of the input faecal sludge which hinders the advancement of anaerobic digestion treatment and downstream nutrient recovery to...

  19. Effects of alkalinity sources on the stability of anaerobic digestion from food waste.

    Science.gov (United States)

    Chen, Shujun; Zhang, Jishi; Wang, Xikui

    2015-11-01

    This study investigated the effects of some alkalinity sources on the stability of anaerobic digestion (AD) from food waste (FW). Four alkalinity sources, namely lime mud from papermaking (LMP), waste eggshell (WES), CaCO3 and NaHCO3, were applied as buffer materials and their stability effects were evaluated in batch AD. The results showed that LMP and CaCO3 had more remarkable effects than NaHCO3 and WES on FW stabilization. The methane yields were 120.2, 197.0, 156.2, 251.0 and 194.8 ml g(-1) VS for the control and synergistic digestions of CaCO3, NaHCO3, LMP and WES added into FW, respectively. The corresponding final alkalinity reached 5906, 7307, 9504, 7820 and 6782 mg l(-1), while the final acidities were determined to be 501, 200, 50, 350 and 250 mg l(-1), respectively. This indicated that the synergism between alkalinity and inorganic micronutrients from different alkalinity sources played an important role in the process stability of AD from FW.

  20. Dynamics of microbial community in a mesophilic anaerobic digester treating food waste: Relationship between community structure and process stability.

    Science.gov (United States)

    Li, Lei; He, Qin; Ma, Yao; Wang, Xiaoming; Peng, Xuya

    2015-01-01

    Organic loading rate (OLR) disturbances were introduced into a mesophilic anaerobic digester treating food waste (FW) to induce stable and deteriorative phases. The microbial community of each phase was investigated using 454-pyrosequencing. Results show that the relative abundance of acid-producing bacteria and syntrophic volatile fatty acid (VFA) oxidizers increased dramatically at deteriorative phase, while the dominant methanogens did not shift from acetoclastic to hydrogenotrophic groups. The mismatching between bacteria and methanogens may partially be responsible for the process deterioration. Moreover, the succession of predominant hydrogenotrophic methanogens reduced the consumption efficiency of hydrogen; meanwhile, the dominant Methanosaeta with low acetate degradation rate, and the increase of inhibitors concentrations further decreased its activity, which may be the other causes for the process failure. These results improve the understanding of the microbial mechanisms of process instability, and provide theoretical basis for the efficient and stable operation of anaerobic digester treating FW.

  1. Near-infrared spectroscopy-based quantification of substrate and aqueous products in wastewater anaerobic fermentation processes

    Institute of Scientific and Technical Information of China (English)

    ZHANG MengLin; SHENG GuoPing; YU HanQing

    2009-01-01

    In this study, a Fourier transform near-infrared (FT-NIR) technique was used for process monitoring of anaerobic fermentation. Orthogonal signal correction (OSC) method was used as NIR spectral pre-processing options. Calibration models were established and the validation of the method was per-formed with the sucrose, ethanol and volatile fatty acids (VFAs) contents determined by the anthrone and gas chromatography methods, respectively. Spectral range and the number of internal latent variables were optimized for the best correlation coefficient. Test set validation of sucrose resulted in excellent measurement of prediction performance and the correlation coefficient of determination is 0.930. Similar prediction statistics for individual VFA and total VFA contents were obtained. These re-sults proved that the NIR spectroscopy technology is able to quantify the contents of both volatile fatty acids and sucrose in wastewater anaerobic fermentation process.

  2. Process stability and microbial community structure in anaerobic hydrogen-producing microflora from food waste containing kimchi.

    Science.gov (United States)

    Jo, Ji Hye; Jeon, Che Ok; Lee, Dae Sung; Park, Jong Moon

    2007-09-15

    Hydrogen production by the dark fermentation of food wastes is an economic and environmentally friendly technology to produce the clean energy source as well as to treat the problematic wastes. However, the long-term operations of the continuous anaerobic reactor for fermentative hydrogen production were frequently unstable. In this study, the structure of microbial community within the anaerobic reactor during unstable hydrogen production was examined by denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) techniques. The changes in microbial community from H(2)-producing Clostridium spp. to lactic acid-producing Lactobacillus spp. were well coincident with the unexpected process failures and the changes of metabolites concentrations in the effluent of the anaerobic reactor. As the rate of hydrogen production decreased, effluent lactic acid concentration increased. Low rate of hydrogen production and changes in microbial community were related to the 'kimchi' content and storage temperature of food waste feed solution. After low temperature control of the storage tank of the feed solution, any significant change in microbial community within the anaerobic reactor did not occur and the hydrogen production was very stably maintained for a long time.

  3. [Accelerating effects of immobilized anthanquinone on the anaerobic biodegradation].

    Science.gov (United States)

    Guo, Jian-bo; Zhou, Ji-ti; Wang, Dong; Tian, Cun-ping; Wang, Ping; Wang, Jing; Salah, Uddin; Li, Li-hua

    2006-10-01

    The accelerating effect of anthanquinone as a redox mediator in the bio-decolorization was conducted. Decolorization of azo dyes was carried out experimentally using the salt-tolerant bacteria under immobilized anthanquinone and high salt conditions. Anthnaquinone used as a redox mediator was able to increase the decolorization rate of wastewater containing azo dyes, and was immobilized by entrapment in calcium alginate (CA), polyvinyl alcohol (PVA)-H3BO3, polyvinyl alcohol (PVA)-calcium alginate (CA) and agar, respectively. The effects of various operating conditions such as anthnaquinone bead number and dissolved oxygen on microbial decolorization were investigated experimentally. At the same time, immobilized anthanquinone was tested to assess the effects on the change of the oxidation-reduction potential (ORP) values during the decolorization processes. High decolorization rate was obtained in the presence of 200 anthnaquinone immobilization beads at 30 degrees C, which increased 1.5-2 fold, in comparison with the control of free-anthanquinone. The oxidation-reduction potential (ORP) values stabilized around -260 to approximately -265 mV after 6 hours anoxic conditions, which lowered ORP values around -10 to approximately -15 mV by anthanquinone. The reusability of the anthnaquinone immobilization beads was evaluated with repeated-bacth decolorization experiments. After four repeated experiments, the decolorization rate of calcium alginate (CA) immobilized anthnaquinone retained over 90% of their original activity.

  4. The effect of managing nutrients in the performance of anaerobic digesters of municipal wastewater treatment plants.

    Science.gov (United States)

    Demirer, Sibel Uludag; Taskin, Bilgin; Demirer, Goksel N; Duran, Metin

    2013-09-01

    Is it possible to create conditions in the anaerobic digesters to control nutrients without changing the performance of a reactor? This study investigates an answer for this question. To this purpose, anaerobic reactors are operated at high concentrations of Mg(2+) ion to harvest the nutrient ions (NH4 (+) and PO4 (3-)) in the form of struvite, that is, magnesium ammonium phosphate. The effects of this modification on the anaerobic digestion of sewage sludge were investigated in terms of chemical oxygen demand (COD) removal and cumulative CH4 production as well as the changes in the biological diversity. The results showed that approximately 50 % of the nutrients (NH4 (+) and PO4 (3-)) were removed regardless of the method adopted for the addition of Mg(2+) ion, slug or daily dosing. The numbers of Methanosaeta and Methanosarcina in the samples withdrawn prior to and after the addition of Mg(2+) did not show significant difference according to the results obtained from qPCR analyses. The research results showed that the addition of Mg(2+) into the anaerobic digesters in municipal wastewater treatment facilities may help to remove the nutrients from the effluent while recovering in their solid forms.

  5. Effect of food to microorganism ratio on biohydrogen production from food waste via anaerobic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jinming [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China); Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Zhang, Ruihong; Sun, Huawei [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); El-Mashad, Hamed M. [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Department of Agricultural Engineering, Mansoura University, El-Mansoura (Egypt); Ying, Yibin [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China)

    2008-12-15

    The effect of different food to microorganism ratios (F/M) (1-10) on the hydrogen production from the anaerobic batch fermentation of mixed food waste was studied at two temperatures, 35 {+-} 2 C and 50 {+-} 2 C. Anaerobic sludge taken from anaerobic reactors was used as inoculum. It was found that hydrogen was produced mainly during the first 44 h of fermentation. The F/M between 7 and 10 was found to be appropriate for hydrogen production via thermophilic fermentation with the highest yield of 57 ml-H{sub 2}/g VS at an F/M of 7. Under mesophilic conditions, hydrogen was produced at a lower level and in a narrower range of F/Ms, with the highest yield of 39 ml-H{sub 2}/g VS at the F/M of 6. A modified Gompertz equation adequately (R{sup 2} > 0.946) described the cumulative hydrogen production yields. This study provides a novel strategy for controlling the conditions for production of hydrogen from food waste via anaerobic fermentation. (author)

  6. Continuous cultivation of Chlorella pyrenoidosa using anaerobic digested starch processing wastewater in the outdoors.

    Science.gov (United States)

    Chu, Hua-Qiang; Tan, Xiao-Bo; Zhang, Ya-Lei; Yang, Li-Bin; Zhao, Fang-Chao; Guo, Jun

    2015-06-01

    Microalgae cultivation using wastewater might be a suitable approach to support sustainable large-scale biomass production. Its compelling characteristics included the recycling of nutrients and water resources, reducing carbon emissions and harvesting available biomass. In outdoor batch and continuous cultures, Chlorella pyrenoidosa completely adapted to anaerobic digested starch processing wastewater and was the dominant microorganism in the photobioreactor. However, seasonal changes of environmental conditions significantly influenced biomass growth and lipid production. The long-term outdoor operation demonstrated that the biomass concentration and productivity in continuous operations at different hydraulic retention times (HRTs) can be successfully predicted using the kinetic growth parameters obtained from the batch culture. A moderate HRT (4days) in the summer provided the best microalgae and lipid production and achieved relatively high biomass concentrations of 1.29-1.62g/L, biomass productivities of 342.6±12.8mg/L/d and lipids productivities of 43.37±7.43mg/L/d.

  7. Ubiquitous anaerobic ammonium oxidation in inland waters of China: an overlooked nitrous oxide mitigation process.

    Science.gov (United States)

    Zhu, Guibing; Wang, Shanyun; Zhou, Leiliu; Wang, Yu; Zhao, Siyan; Xia, Chao; Wang, Weidong; Zhou, Rong; Wang, Chaoxu; Jetten, Mike S M; Hefting, Mariet M; Yin, Chengqing; Qu, Jiuhui

    2015-11-27

    Denitrification has long been regarded as the only pathway for terrestrial nitrogen (N) loss to the atmosphere. Here we demonstrate that large-scale anaerobic ammonium oxidation (anammox), an overlooked N loss process alternative to denitrification which bypasses nitrous oxide (N2O), is ubiquitous in inland waters of China and contributes significantly to N loss. Anammox rates in aquatic systems show different levels (1.0-975.9 μmol N m(-2) h(-1), n = 256) with hotspots occurring at oxic-anoxic interfaces and harboring distinct biogeochemical and biogeographical features. Extrapolation of these results to the China-national level shows that anammox could contribute about 2.0 Tg N yr(-1), which equals averagely 11.4% of the total N loss from China's inland waters. Our results indicate that a significant amount of the nitrogen lost from inland waters bypasses denitrification, which is important for constructing more accurate climate models and may significantly reduce potential N2O emission risk at a large scale.

  8. Effect of saponification on the anaerobic digestion of solid fatty residues.

    Science.gov (United States)

    Mouneimne, A H; Carrère, H; Bernet, N; Delgenès, J P

    2003-10-01

    In France, fatty residues considered as "non-ultimate" waste will not be accepted in landfill from 2002, in accordance with French legislation. Anaerobic digestion appears as an alternative process to mobilize and profitably use such fermentable waste. In this work, the effect of an alkaline pretreatment on the degradation of hexane extractible matter (HEM) and the production of volatile fatty acids (VFAs) was compared in reactors working at pH 6.5 and 8.5. The results obtained showed that 40% (+/- 0.1) of HEM were degraded at pH 8.5 versus 10% (+/- 0.3) at pH 6.5, regardless of the alkali agent used to saponify the greasy wastes. The highest performances of VFA production (8.45% +/- 0.3) were obtained at pH 8.5 with greases saponified by potassium hydroxide, compared to results (4.25% +/- 0.1) with greasy waste saponified by sodium hydroxide. This difference in VFA production might be attributable to biotoxic molecules generated during the saponification of greases by soda, limiting consequently the VFA production process.

  9. Volatile fatty acids production from anaerobic treatment of cassava waste water: effect of temperature and alkalinity.

    Science.gov (United States)

    Hasan, Salah Din Mahmud; Giongo, Citieli; Fiorese, Mônica Lady; Gomes, Simone Damasceno; Ferrari, Tatiane Caroline; Savoldi, Tarcio Enrico

    2015-01-01

    The production of volatile fatty acids (VFAs), intermediates in the anaerobic degradation process of organic matter from waste water, was evaluated in this work. A batch reactor was used to investigate the effect of temperature, and alkalinity in the production of VFAs, from the fermentation of industrial cassava waste water. Peak production of total volatile fatty acids (TVFAs) was observed in the first two days of acidogenesis. A central composite design was performed, and the highest yield (3400 mg L(-1) of TVFA) was obtained with 30°C and 3 g L(-1) of sodium bicarbonate. The peak of VFA was in 45 h (pH 5.9) with a predominance of acetic (63%) and butyric acid (22%), followed by propionic acid (12%). Decreases in amounts of cyanide (12.9%) and chemical oxygen demand (21.6%) were observed, in addition to the production of biogas (0.53 cm(3) h(-1)). The process was validated experimentally and 3400 g L(-1) of TVFA were obtained with a low relative standard deviation.

  10. The importance of copper in pig-farming, the anaerobic process and the environment; Cobre: su importancia en porcicultura, proceso anaerobio y medio ambiente

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Borges, E.; Poggi Varaldo, H. M.

    2006-07-01

    A review of the literature forms the basis for assessing the incidence of copper forms pig-farming waste, the use of the anaerobic process and the presence of this element in bodies of water. Since the optimum amounts of minerals for promoting growth in pigs is not known, there is a tendency to employ large amounts of food supplements containing trace metals, including copper, which then pass into pig waste. Copper is present in the anaerobic process in hydrogenase, an enzyme involved in the biotransformation of hydrogen into biogas. The toxic and inhibitory levels of copper during the anaerobic processing of organic matter are given. (Author) 22 refs.

  11. Comprehensive microbial analysis of combined mesophilic anaerobic-thermophilic aerobic process treating high-strength food wastewater.

    Science.gov (United States)

    Jang, Hyun Min; Ha, Jeong Hyub; Park, Jong Moon; Kim, Mi-Sun; Sommer, Sven G

    2015-04-15

    A combined mesophilic anaerobic-thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT) = 40 d (corresponding OLR = 3.5 kg COD/m(3) d) and Run II with HRT = 20 d (corresponding OLR = 7 kg COD/m(3)). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher organic matter removal efficiencies (over 90%) of TS, VS and COD and methane production than did R3. Quantitative real-time PCR (qPCR) results indicated that higher populations of both bacteria and archaea were maintained in R1 than in R3. Pyrosequencing analysis revealed relatively high abundance of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera (Prevotella, Aminobacterium, Geobacillus and Unclassified Actinobacteria), which suggests synergy between mesophilic anaerobic digestion and thermophilic aerobic digestion. For archaea, in R1 methanogenic archaea shifted from genus Methanosaeta to Methanosarcina, whereas genera Methanosaeta, Methanobacterium and Methanoculleus were predominant in R3. The results demonstrated dynamics of key microbial populations that were highly consistent with an enhanced reactor performance of the combined process.

  12. Treatment of anaerobic digester effluents of nylon wastewater through chemical precipitation and a sequencing batch reactor process.

    Science.gov (United States)

    Huang, Haiming; Song, Qianwu; Wang, Wenjun; Wu, Shaowei; Dai, Jiankun

    2012-06-30

    Chemical precipitation, in combination with a sequencing batch reactor (SBR) process, was employed to remove pollutants from anaerobic digester effluents of nylon wastewater. The effects of the chemicals along with various Mg:N:P ratios on the chemical precipitation (struvite precipitation) were investigated. When brucite and H(3)PO(4) were applied at an Mg:N:P molar ratio of 3:1:1, an ammonia-removal rate of 81% was achieved, which was slightly more than that (80%) obtained with MgSO(4)·7H(2)O and Na(2)HPO(4)·12H(2)O at Mg:N:P molar ratios greater than the stoichiometric ratio. To further reduce the ammonia loads of the successive biotreatment, an overdose of phosphate with brucite and H(3)PO(4) was applied during chemical precipitation. The ammonia-removal rate at the Mg:N:P molar ratio of 3.5:1:1.05 reached 88%, with a residual PO(4)-P concentration of 16 mg/L. The economic analysis showed that the chemical cost of chemical precipitation could be reduced by about 41% when brucite and H(3)PO(4) were used instead of MgSO(4)·7H(2)O and Na(2)HPO(4)·12H(2)O. The subsequent biological process that used a sequencing batch reactor showed high removal rates of contaminants. The quality of the final effluent met the requisite effluent-discharging standards.

  13. Modeling multi-component transport and enhanced anaerobic dechlorination processes in a single fracture-clay matrix system

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Broholm, Mette Martina; Binning, Philip John;

    2010-01-01

    and the contaminant flux out of the clay system are assessed for different distributions of microbial degradation. Results from a set of scenarios show that time to remove 90% of the initial mass is halved when dechlorination occurs in a 5 cm reaction zone in the clay at the fracture-matrix interface (from 419 to 195...... to the physical processes, mainly diffusion in the matrix, than to the biogeochemical processes, when dechlorination is assumed to take place in a limited reaction zone only. The inclusion of sequential dechlorination in clay fracture transport models is crucial, as the contaminant flux to the aquifer...... of a contaminant in a single fracture-clay matrix system coupled with a reactive model for anaerobic dechlorination. The model takes into account microbially driven anaerobic dechlorination, where sequential Monod kinetics with competitive inhibition is used to model the reaction rates, and degradation...

  14. Anaerobic digestion of fruit and vegetable processing wastes for biogas production

    Energy Technology Data Exchange (ETDEWEB)

    Viswanath, P.; Sumithra Devi, S.; Nand, K. (Central Food Technological Research Inst., Mysore (IN))

    1992-01-01

    The effect of feeding different fruit and vegetable wastes, mango, pineapple, tomato, jackfruit, banana and orange, was studied in a 60-litre digester by cycling each waste every fifth day in order to operate the digester as and when there was supply of feed. The characteristics of the anaerobically digested fluid and digester performance in terms of biogas production were determined at different loading rates (LR) and at different hydraulic retention times (HRT) and the maximum biogas yield of 0.6 m{sup 3}/kg VS added was achieved at a 20-day HRT and 40 kg TS m{sup -3}day{sup -1} loading rate. The hourly gas production was observed in the digesters operated at 16 and 24 days HRT. The major yield (74.5%) of gas was produced within 12h of feeding at a 16-day HRT whereas at a 24-day HRT only 59.03% of the total gas could be obtained at this time. (author).

  15. Biohydrogen production from cheese processing wastewater by anaerobic fermentation using mixed microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Peilin [Department of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, MS 39762 (United States); Zhang, Ruihong [Department of Biological and Agricultural Engineering, University of California at Davis, Davis, CA 95616 (United States); McGarvey, Jeffery A. [U.S. Department of Agriculture, Agricultural Research Service, Foodborne Contaminants Research Unit, Albany, CA 94710 (United States); Benemann, John R. [Benemann Associates, Walnut Creek, CA 94595 (United States)

    2007-12-15

    Hydrogen (H{sub 2}) production from simulated cheese processing wastewater via anaerobic fermentation was conducted using mixed microbial communities under mesophilic conditions. In batch H{sub 2} fermentation experiments H{sub 2} yields of 8 and 10 mM/g COD fed were achieved at food-to-microorganism (F/M) ratios of 1.0 and 1.5, respectively. Butyric, acetic, propionic, and valeric acids were the major volatile fatty acids (VFA) produced in the fermentation process. Continuous H{sub 2} fermentation experiments were also performed using a completely mixed reactor (CSTR). The pH of the bioreactor was controlled in a range of 4.0-5.0 by addition of carbonate in the feed material. Maximum H{sub 2} yields were between 1.8 and 2.3 mM/g COD fed for the loading rates (LRs) tested with a hydraulic retention time (HRT) of 24 h. Occasionally CH{sub 4} was produced in the biogas with concurrent reductions in H{sub 2} production; however, continuous H{sub 2} production was achieved for over 3 weeks at each LR. The 16S rDNA analysis of DNA extracted from the bioreactors during periods of high H{sub 2} production revealed that more than 50% of the bacteria present were members of the genus Lactobacillus and about 5% were Clostridia. When H{sub 2} production in the bioreactors decreased concurrent reductions in the genus Lactobacillus were also observed. Therefore, the microbial populations in the bioreactors were closely related to the conditions and performance of the bioreactors. (author)

  16. Anaerobe Tolerance to Oxygen and the Potentials of Anaerobic and Aerobic Cocultures for Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    M.T. Kato

    1997-12-01

    Full Text Available The anaerobic treatment processes are considered to be well-established methods for the elimination of easily biodegradable organic matter from wastewaters. Some difficulties concerning certain wastewaters are related to the possible presence of dissolved oxygen. The common belief is that anaerobes are oxygen intolerant. Therefore, the common practice is to use sequencing anaerobic and aerobic steps in separate tanks. Enhanced treatment by polishing off the residual biodegradable oxygen demand from effluents of anaerobic reactors, or the biodegradation of recalcitrant wastewater pollutants, usually requires sequenced anaerobic and aerobic bacteria activities. However, the combined activity of both bacteria can also be obtained in a single reactor. Previous experiments with either pure or mixed cultures showed that anaerobes can tolerate oxygen to a certain extent. The oxygen toxicity to methanogens in anaerobic sludges was quantified in batch experiments, as well as in anaerobic reactors. The results showed that methanogens have a high tolerance to oxygen. In practice, it was confirmed that dissolved oxygen does not constitute any detrimental effect on reactor treatment performance. This means that the coexistence of anaerobic and aerobic bacteria in one single reactor is feasible and increases the potentials of new applications in wastewater treatment

  17. Stable isotope composition of biogas allows early warning of complete process failure as a result of ammonia inhibition in anaerobic digesters.

    Science.gov (United States)

    Lv, Zuopeng; Hu, Meng; Harms, Hauke; Richnow, Hans Hermann; Liebetrau, Jan; Nikolausz, Marcell

    2014-09-01

    Four 15-L lab-scale continuous stirred tank reactors were operated under mesophilic conditions to investigate the effect of ammonia inhibition. Stable isotope fingerprinting of biogas was applied as a process monitoring tool. Ammonia inhibition was initiated by amendment of chicken manure to maize silage fed reactors. During the accumulation of ammonia, the concentration of volatile fatty acids increased while the biogas production and pH decreased. However, in one reactor, an inhibited steady state with stable gas production even at high ammonia levels was achieved, while the other reactor proceeded to complete process failure. A depletion of the δ(13)CH4 and δ(13)CO2 values preceded the process inhibition. Moreover, the stable isotope composition of biogas also forecasted the complete process failure earlier than other standard parameters. The stable isotope analyses of biogas have a potential for mechanistic insights in anaerobic processes, and may be used to pre-warn process failure under stress conditions.

  18. Metabolic and microbial community dynamics during the anaerobic digestion of maize silage in a two-phase process.

    Science.gov (United States)

    Sträuber, Heike; Lucas, Rico; Kleinsteuber, Sabine

    2016-01-01

    Two-phasic anaerobic digestion processes (hydrolysis/acidogenesis separated from acetogenesis/methanogenesis) can be used for biogas production on demand or a combined chemicals/bioenergy production. For an effective process control, detailed knowledge about the microbial catalysts and their correlation to process conditions is crucial. In this study, maize silage was digested in a two-phase process and interrelationships between process parameters and microbial communities were revealed. In the first-phase reactor, alternating metabolic periods were observed which emerged independently from the feeding frequency. During the L-period, up to 11.8 g L(-1) lactic acid was produced which significantly correlated to lactic acid bacteria of the genus Lactobacillus as the most abundant community members. During the alternating G-period, the production of volatile fatty acids (up to 5.3, 4.0 and 3.1 g L(-1) for propionic, n-butyric and n-caproic acid, respectively) dominated accompanied by a high gas production containing up to 28 % hydrogen. The relative abundance of various Clostridiales increased during this metabolic period. In the second-phase reactor, the metabolic fluctuations of the first phase were smoothed out resulting in a stable biogas production as well as stable bacterial and methanogenic communities. However, the biogas composition followed the metabolic dynamics of the first phase: the hydrogen content increased during the L-period whereas highest CH4/CO2 ratios (up to 2.8) were reached during the G-period. Aceticlastic Methanosaeta as well as hydrogenotrophic Methanoculleus and Methanobacteriaceae were identified as dominant methanogens. Consequently, a directed control of the first-phase stabilizing desired metabolic states can lead to an enhanced productivity regarding chemicals and bioenergy.

  19. Quantitative and qualitative transitions of methanogen community structure during the batch anaerobic digestion of cheese-processing wastewater.

    Science.gov (United States)

    Lee, Changsoo; Kim, Jaai; Shin, Seung Gu; O'Flaherty, Vincent; Hwang, Seokhwan

    2010-08-01

    Qualitative and quantitative shifts in methanogen community structure, associated with process performance data, were investigated during the batch anaerobic digestion of a cheese-processing wastewater, whey permeate. Denaturing gradient gel electrophoresis (DGGE) and real-time PCR techniques were applied to obtain qualitative and quantitative microbial data sets, respectively, based on methanogen 16S rRNA genes. Throughout the operation, dynamic variations in both qualitative and quantitative community structures were observed, with repeated shifts in dominance between the aceticlastic Methanosarcinaceae (suggested mainly by the detection of a Methanosarcina-like population) and the hydrogenotrophic Methanomicrobiales (suggested mainly by the detection of a Methanofollis-like population). This trend corresponded well to the diauxic utilization of acetate and longer-chain fatty acids (C(3)-C(6)), mainly propionate. Joint-plot non-metric multidimensional scaling (NMS) analysis demonstrated that the qualitative and quantitative community shifts had significant correlations with the composition of residual organic acids and the methane production rate, respectively. This suggests the potential use of microbial community shift analysis as an indicative tool for diagnosing anaerobic digestion processes. The results suggest that more attention should be directed to quantitative, as well as qualitative, approaches for a better understanding of anaerobic digestion, particularly in terms of biogas production efficiency, under dynamic and transitional conditions.

  20. The Effects of Acoustic Disturbance on Anaerobic Endurance in Female Volleyball Players

    Directory of Open Access Journals (Sweden)

    Sienkiewicz-Dianzenza Edyta

    2015-03-01

    Full Text Available Purpose.The purpose of the study was to assess anaerobic endurance in volleyball players through repeated vertical jump performance under quiet and noisy conditions. Methods. A group of 12 female players aged 19-28 year completed six sets of eight standing vertical jump jumps; jump height and heart rate before and after the protocol were measured in quiet and noisy (fan cheering conditions. Results. Maximum and minimum vertical jump heights were higher and intragroup differences were smaller in noisy than quiet conditions. Conclusions. Vertical jump testing, a measure of physical activity typical of volleyball, is suitable for monitoring training effects. The influence of noise typical during volleyball matches had a positive effect on player performance and anaerobic endurance.

  1. Effect of anaerobic digestion on the high rate of nitritation, treating piggery wastewater

    Institute of Scientific and Technical Information of China (English)

    Jiyeol Im; Kyungik Gil

    2011-01-01

    The amount of piggery wastewater as domestic livestock is increasing.The volume of piggery wastewater produced is less than the volume of other wastewaters,but piggery wastewater has a heavy impact on wastewater streams due to an extremely high concentration of nitrogen and COD.In this study,laboratory reactors were operated using piggery wastewater and the effluent of anaerobic digester from piggery wastewater plants.The purpose of this study was to induce the nitritation process,which is an economically advantageous nitrogen removal method that converts ammonium nitrogen into nitrite.The results showed that the effluent of anaerobic digester from piggery wastewater was more efficient than raw piggery wastewater in terms of inducing nitritation.It can be deduced that nitritation is largely affected by an organic fraction of piggery wastewater.It can also be concluded that a small amount of biodegradable organic matter in piggery wastewater is efficient in inducing nitritation.

  2. ANAEROBIC DIGESTION MODEL ANALYSIS OF THE FERMENTATION PROCESS IN PSYCHROPHILIC AND MESOPHILIC CHAMBER IN ACCORDANCE WITH THE AMOUNT OF BIOGAS SOURCED

    Directory of Open Access Journals (Sweden)

    Dariusz Zdebik

    2015-03-01

    Full Text Available The paper presents problems concerning the modelling of anaerobic sludge stabilization, with the additional substrate (waste transported, dairy butchery sewage in psychrophilic fermentation conditions in the range 10–20 °C and mesophilic at 35 °C. Simulation test was conducted in the two digesters. Results of the study allowed to evaluate the effectiveness of conducting these processes in separate chambers, i.e. the psychrophilic and mesophilic chamber. During the simulations, terms of obtaining volatile fatty acids and biogas in conjunction with the operating conditions of the chambers indicated.

  3. [Effect of moisture content on anaerobic methanization of municipal solid waste].

    Science.gov (United States)

    Qu, Xian; He, Pin-Jing; Shao, Li-Ming; Bouchez, Théodore

    2009-03-15

    Biogas production, gas and liquid characteristics were investigated for comparing the effect of moisture content on methanization process of MSW with different compositions of food waste and cellulosic waste. Batch reactors were used to study the anaerobic methanization of typical Chinese and French municipal solid waste (MSW) and cellulosic waste with different moisture content, as 35%, field capacity (65%-70%), 80%, and saturated state (> 95%). The results showed that for the typical Chinese and French waste, which contained putrescible waste, the intermediate product, VFA, was diluted by high content of water, which helped to release the VFA inhibition on hydrolysis and methanization. Mass amount of methane was produced only when the moisture content of typical French waste was higher than 80%, while higher content of moisture was needed when the content of putrescible waste was higher in MSW, as > 95% for typical Chinese waste. Meanwhile the methane production rate and the ultimate cumulated methane production were increased when moisture content was leveled up. The ultimate cumulated methane production of the typical French waste with saturated state was 0.6 times higher than that of the waste with moisture content of 80%. For cellulosic waste, high moisture content of cellulosic materials contributed to increase the attachment area of microbes and enzyme on the surface of the materials, which enhance the waste hydrolysis and methanization. When the moisture content of the cellulosic materials increased from field capacity (65%) to saturated state (> 95%), the ultimate cumulated methane production increased for 3.8 times.

  4. Effect of temperature on the treatment of domestic wastewater with a staged anaerobic fluidized membrane bioreactor.

    Science.gov (United States)

    Yoo, R H; Kim, J H; McCarty, P L; Bae, J H

    2014-01-01

    A laboratory staged anaerobic fluidized membrane bioreactor (SAF-MBR) system was applied to the treatment of primary clarifier effluent from a domestic wastewater treatment plant with temperature decreasing from 25 to 10 °C. At all temperatures and with a total hydraulic retention time of 2.3 h, overall chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) removals were 89% and 94% or higher, with permeate COD and BOD5 of 30 and 7 mg/L or lower, respectively. No noticeable negative effects of low temperature on organic removal were found, although a slight increase to 3 mg/L in volatile fatty acids concentrations in the effluent was observed. Biosolids production was 0.01-0.03 kg volatile suspended solids/kg COD, which is far less than that with aerobic processes. Although the rate of trans-membrane pressure at the membrane flux of 9 L/m(2)/h increased as temperature decreased, the SAF-MBR was operated for longer than 200 d before chemical cleaning was needed. Electrical energy potential from combustion of the total methane production (gaseous and dissolved) was more than that required for system operation.

  5. Effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester.

    Science.gov (United States)

    Espinosa-Solares, Teodoro; Valle-Guadarrama, Salvador; Bombardiere, John; Domaschko, Max; Easter, Michael

    2009-05-01

    The effect of heating strategy on power consumption and performance of a pilot plant anaerobic digester treating chicken litter, under thermophilic conditions, has been studied. Heating strategy was evaluated using three different spans (0.2 degrees C, 0.6 degrees C, and 1.0 degree C) for triggering the temperature control system from target temperature (56.7 degrees C). The hydraulic retention time in the pilot plant digester was in the range of 32 to 37 days, varying the total solids concentration fed from 5% to 6%. The results showed that under the experimental conditions, heating was the most energy-demanding process with 95.5% of the energy used. Increments up to 7.5% and 3.8%, respectively, on mechanical and heating power consumption, were observed as the span, for triggering the temperature control system from target temperature, was increased. Under the experimental conditions studied here, an increment of 30.6% on the global biodigester performance index was observed when a span of 1.0 degree C was compared to the one of 0.2 degrees C.

  6. [Characterisation of excess sludge reduction in an anoxic + oxic-settling-anaerobic activated sludge process].

    Science.gov (United States)

    Gao, Xu; Lu, Yan-Hua; Guo, Jin-Song

    2009-05-15

    An energy balance analysis method with auto calorimeter being adopted was introduced to determine calorific values of sludge samples in influent and effluent of uncoupling tank in an anoxic (A) + oxic-settling-anaerobic (OSA) process and a reference system. The affiliation of sludge amount change and its energy content were studied, as well as potential of excess sludge reduction was evaluated through modifying performance of uncoupling tank. The characteristi s and causes of sludge reduction in OSA system were deduced according to energy and matter balance analysis. Results show that when the hydraulic retention time (HRT) of uncoupling tank are 5.56 h, 7.14 h and 9 h, the excess sludge reduction of whole A + OS Asystem are 1.236 g/d, 0.771 g/d and 0.599 g/d respectively. Energy content of sludge flows into and out of the uncoupling tank changes, the specific calorific value of sludge in effluent is inclined to be higher than that in influent with the HRT of the tank increasing: there isn't any significant difference of sludge calorific values between influent and effluent at 5.56 h, while the differences are in 99-113 J/g at 7.14 h, and 191-329 J/g at 9 h. Sludge in uncoupling tank would decay and longer HRT will result in more attenuation. It could be concluded that excess sludge reduction of A + OSA system is caused by both of sludge decay in uncoupling tank and sludge proliferation in AO reaction zone.

  7. Anaerobic digestion of different feedstocks: impact on energetic and environmental balances of biogas process.

    Science.gov (United States)

    Bacenetti, Jacopo; Negri, Marco; Fiala, Marco; González-García, Sara

    2013-10-01

    The possibility of limiting the global warming is strictly linked to the reduction of GHG emissions. Renewable energy both allows reducing emissions and permits to delay fossil fuel depletion. The anaerobic digestion of animal manure and energy crops is a promising way of reducing GHG emissions. In Italy agricultural biogas production was considerably increased; nowadays there are about 520 agricultural biogas plants. The increasing number of biogas plants, especially of those larger than 500 kW(e) (electrical power), involves a high consumption of energy crops, large transport distances of biomass and digestate and difficulties on thermal energy valorization. In this study the energetic (CED) and environmental (GHG emissions) profiles associated with the production of electricity derived from biogas have been identified. Three biogas plants located in Northern Italy have been analyzed. The study has been carried out considering a cradle-to-grave perspective and thus, special attention has been paid on the feedstock production and biogas production process. The influences on the results taking into account different plant sizes and feeding rate has been assessed in detail. Energy analysis was performed using the Cumulative Energy Demand method (CED). The climate change was calculated for a 100-year time frame based on GHG emissions indicated as CO2 equivalents (eq) and defined by the IPCC (2006). In comparison to the fossil reference system, the electricity production using biogas saves GHG emissions from 0.188 to 1.193 kg CO2eq per kWh(e). Electricity supply from biogas can also contribute to a considerable reduction of the use of fossil energy carriers (from -3.97 to 10.08 MJ(fossil) per kWh(e)). The electricity production from biogas has a big potential for energy savings and reduction of GHG emissions. Efficient utilization of the cogenerated heat can substantially improve the GHG balance of electricity production from biogas.

  8. An innovative bioelectrochemical-anaerobic digestion-coupled system for in-situ ammonia recovery and biogas enhancement: process performance and microbial ecology

    OpenAIRE

    Zhang, Yifeng; Angelidaki, Irini

    2014-01-01

    Ammonia (NH4+/NH3) inhibition during anaerobic digestion process is one of the most frequent problems existing in biogas plants, resulting in unstable process and reduced biogas production. In this study, we developed a novel hybrid system, consisted of a submersed microbial resource recovery cell (SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production. In batch experiment, the ammonia c...

  9. On improving effect combining aerobic and anaerobic loads of character in the classroom for physical training in universities

    Directory of Open Access Journals (Sweden)

    Goginava S.E.

    2014-06-01

    Full Text Available Purpose: substantiate the health effects on the body through a combination of students in the classroom for physical training loads of aerobic and anaerobic nature. Material : the study involved 174 students of 1-3 courses NIU "BSU." Of these, 90 girls and 84 boys aged 17-20 years. Results : the specificity of the health effects of athletic gymnastics as a means of anaerobic training students. The specificity of the health effects of swimming as a means of improving aerobic exercise. Expediency and the method of load combination of aerobic and anaerobic focus on employment in physical education with students. Conclusions: results of scientific studies show that the load combination of aerobic and anaerobic characters on physical education classes at the university promotes the significant increase in the level of physical health of students of the basic training department.

  10. Anaerobic Biodegradation of Detergent Surfactants

    Directory of Open Access Journals (Sweden)

    Erich Jelen

    2009-03-01

    Full Text Available Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants.

  11. Effect of digestion time on anaerobic digestion with high ammonia concentration

    Science.gov (United States)

    Oktavitri, Nur Indradewi; Purnobasuki, Hery; Kuncoro, Eko Prasetyo; Purnamasari, Indah; Semma Hadinnata, P.

    2016-03-01

    Anaerobic digestion was developed to treat high concentration organic compound efficiently in certain Digestion Time (DT). High ammonia concentration could influenced removal organic compound in digestion. This bench scale study investigated the effect of digestion time on anaerobic batch reactor with high ammonia concentration. Total Ammonia Nitrogen (TAN) concentration was adjusted 4000 and 5000 mg/1, Digestion time was ranged from 0-26 d, operation temperature was ranged from 28-29°C, inoculum was collected from slaughter house sludge. The degradation of Chemical Oxygen Demand (COD) correlated with digestion time. The concentration of TAN from synthetic wastewater contain 5000 mg/1 of TAN more fluctuated than those use 4000 mg/1 of TAN. However, the biogas production from wastewater contained 4000 mg/1 of TAN gradually increased until 24 d of DT. The reactor contain 5000 mg/1 of TAN only growth until 12 d and steady state at over 12 d of digestion time.

  12. Biogas production from food-processing industrial wastes by anaerobic digestion

    DEFF Research Database (Denmark)

    Fang, Cheng

    Konfronteret med energikrise og klimaforandringer, har verden brug for grønne, effektive og kulstofneutrale energikilder, som kan erstatte fossile brændstoffer. Biogas, som dannes ved anaerob nedbrydning af organisk materiale, er en bæredygtig, pålidelig og vedvarende energikilde. Der er stor uud...

  13. Changes in bacterial and fungal abundance in the soil during the process of anaerobic soil disinfestation

    NARCIS (Netherlands)

    Streminska, M.A.; Wurff, van der A.W.G.; Runia, W.T.; Thoden, T.C.; Termorshuizen, A.J.; Feil, H.

    2014-01-01

    Anaerobic soil disinfestation (ASD) has potential to reduce soilborne plant pathogens as a sustainable alternative for chemical or energy-demanding steam treatments. It involves adding a labile carbon source, irrigating the soil to stimulate decomposition of organic material and then covering the so

  14. Diagnosis of the anaerobic reject water effects on WWTP operational characteristics as a precursor of bulking and foaming.

    Science.gov (United States)

    Erdirençelebi, Dilek; Küçükhemek, Murat

    2015-01-01

    This study investigates the effects observed on operational parameters in a large and full-scale wastewater treatment plant subjected to anaerobic reject water (ARW) diversion off the main line for a 3-month period and further monitoring for a 2-year period. The plant's secondary unit consists of a two-stage plug-flow-modified Bardenpho process receiving wastewater from both municipal and industrial origins. As a result, ARW was found to have a direct effect on bulking in secondary clarifiers and foaming in anaerobic digesters (AD) despite its relatively small flow rate. During the cut-off period a highly stable sludge volume index at 80 mL g(-1) level was obtained in the secondary clarifiers, effluent suspended solids concentration was reduced and continuous feeding to AD was recovered. Sludge density increased in the thickeners during hot season. Secondary clarifiers showed good and stable settleability despite low dissolved oxygen, food/microorganism ratio and high sludge retention time and ammonium levels in the biological unit. The bulking and foaming effect was presented on the plant's internal flow balance. ARW needs serious consideration for elimination by appropriate technologies because of its high potential as a multi-dimensional pollutant source, not only as a carrier of nutrients but also as a possible carrier of filamentous bacteria, which might promote chronic seeding and retention in the system.

  15. Effect of inorganic carbon on anaerobic ammonium oxidation enriched in sequencing batch reactor

    Institute of Scientific and Technical Information of China (English)

    Liao Dexiang; Li Xiaoming; Yang Qi; Zeng Guangming; Guo Liang; Yue Xiu

    2008-01-01

    The present lab-scale research reveals the enrichment of anaerobic ammonium oxidation microorganism from methanogenic anaerobic granular sludge and the effect of inorganic carbon (sodium bicarbonate) on anaerobic ammonium oxidation. The enrichment of anammox bacteria was carried out in a 7.0-L SBR and the effect of bicarbonate on anammox was conducted in a 3.0-L SBR. Research results , especially the biomass, showed first signs of anammox activity after 54 d cultivation with synthetic wastewater, when the pH was controlled between 7.5 and 8.3, the temperature was 35℃. The anammox activity increased as the influent bicarbonate concentration increased from 1.0 to 1.5 g/L and then, was inhibited as the bicarbonate concentration approached 2.0 g/L. However, the activity could be restored by the reduction of bicarbonate concentration to 1.0 g/L, as shown by rapid conversion of ammonium, and nitrite and nitrate production with normal stoichiometry. The optimization of the bicarbonate concentration in the reactor could increase the anammox rate up to 66.4 mgN/(L·d).

  16. Production of citric acid using its extraction wastewater treated by anaerobic digestion and ion exchange in an integrated citric acid-methane fermentation process.

    Science.gov (United States)

    Xu, Jian; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2014-08-01

    In order to solve the problem of extraction wastewater pollution in citric acid industry, an integrated citric acid-methane fermentation process is proposed in this study. Extraction wastewater was treated by mesophilic anaerobic digestion and then used to make mash for the next batch of citric acid fermentation. The recycling process was done for seven batches. Citric acid production (82.4 g/L on average) decreased by 34.1 % in the recycling batches (2nd-7th) compared with the first batch. And the residual reducing sugar exceeded 40 g/L on average in the recycling batches. Pigment substances, acetic acid, ammonium, and metal ions in anaerobic digestion effluent (ADE) were considered to be the inhibitors, and their effects on the fermentation were studied. Results indicated that ammonium, Na(+) and K(+) in the ADE significantly inhibited citric acid fermentation. Therefore, the ADE was treated by acidic cation exchange resin prior to reuse to make mash for citric acid fermentation. The recycling process was performed for ten batches, and citric acid productions in the recycling batches were 126.6 g/L on average, increasing by 1.7 % compared with the first batch. This process could eliminate extraction wastewater discharge and reduce water resource consumption.

  17. Effect of solid-state NaOH pretreatment on methane production from thermophilic semi-dry anaerobic digestion of rose stalk.

    Science.gov (United States)

    Liang, Yue-Gan; Cheng, Beijiu; Si, You-Bin; Cao, De-Ju; Li, Dao-Lin; Chen, Jian-Feng

    2016-01-01

    The effects of solid-state NaOH pretreatment on the efficiency of methane production from semi-dry anaerobic digestion of rose (Rosa rugosa) stalk were investigated at various NaOH loadings (0, 1, 2, and 4% (w/w)). Methane production, process stability and energy balance were analyzed. Results showed that solid-state NaOH pretreatment significantly improved biogas and methane yields of 30-day anaerobic digestion, with increases from 143.7 mL/g volatile solids (VS) added to 157.1 mL/g VS -192.1 mL/g VS added and from 81.8 mL/g VS added to 88.8 mL/g VS-117.7 mL/g VS added, respectively. Solid-state NaOH pretreatment resulted in anaerobic digestion with higher VS reduction and lower technical digestion time. The 4% NaOH-treated group had the highest methane yield of 117.7 mL/g VS added, which was 144% higher compared to the no NaOH-treated group, and the highest net energy recovery. Higher rate of lignocellulose breakage and higher process stability of anaerobic digestion facilitated methane production in the NaOH-pretreated groups.

  18. 三价铁离子促进玉米秸秆厌氧发酵%Fe3+enhanced anaerobic digestion process of corn straw

    Institute of Scientific and Technical Information of China (English)

    时昌波; 王进; 彭书传; 侯成虎; 陈天虎; 岳正波※

    2013-01-01

      Anaerobic digestion is one of the effective utilization processes for the resourcization of agricultural wastes. Trace elements are one of the key biological factors that influence the biogas production capacity of organic wastes, especially for the element of iron that has a significant influence on the stability and methane yield of the anaerobic digestion process. However, the iron content in the corn stover normally is low. Therefore, in this experiment FeCl3 was used as the iron source to enhance the anaerobic digestion of corn stover. The experiment was performed in batch modes using the serum bottles as reactors with a working volume of 150 mL. The mass concentration based on the volatile solids (VS ) of corn stover was 50 g/L and FeCl3 dosages were 0%, 0.1%, 0.2%, 0.5%, 1.5%, 3%, 6%of the corn stover VS. The characteristics of the gas and methane generation process, digester solution, and solid digester residues in the five reactors were studied. A modified Gompertz equation was used to describe the gas and methane generation process. Results showed that the methane production of the reactor with 3%FeCl3 was 7.29 L·L-1 which was about 14%higher than that of the control reactor (6.47 L·L-1). Simulation results also showed that the lag time, product yield, and formation rate were different in the reactors. Such a difference could be attributed to the nutrient iron requirements for different anaerobic microorganisms, including hydrolytic and fermentative bacteria, acetogenic bacteria, and methane-producing archaea were different. Cellulose and hemicellulose were the main ingredients of corn stalks, and were also the main biodegradable ingredients of corn stover for the anaerobic digestion process. The lignocelluloses content in the dolif digester residues were analyzed. The mass fractions of neutral detergent fiber, hemicellulose, and cellulose in the digester residue obtained from the reactor with 3%FeCl3 were the lowest, which were 56%, and 6%and 18

  19. The effects of different mixing intensities during anaerobic digestion of the organic fraction of municipal solid waste.

    Science.gov (United States)

    Lindmark, Johan; Eriksson, Per; Thorin, Eva

    2014-08-01

    Mixing inside an anaerobic digester is often continuous and is not actively controlled. The selected mixing regime can however affect both gas production and the energy efficiency of the biogas plant. This study aims to evaluate these effects and compare three different mixing regimes, 150 RPM and 25 RPM continuous mixing and minimally intermittent mixing for both digestion of fresh substrate and post-digestion of the organic fraction of municipal solid waste. The results show that a lower mixing intensity leads to a higher biogas production rate and higher total biogas production in both cases. 25 RPM continuous mixing and minimally intermittent mixing resulted in similar biogas production after process stabilization, while 150 RPM continuous mixing resulted in lower production throughout the experiment. The lower gas production at 150 RPM could not be explained by the inhibition of volatile fatty acids. Cumulative biogas production until day 31 was 295 ± 2.9, 317 ± 1.9 and 304 ± 2.8N ml/g VS added during digestion of fresh feed and 113 ± 1.3, 134 ± 1.1 and 130 ± 2.3N ml/g VS added during post digestion for the 150 RPM, 25 RPM and minimally mixed intensities respectively. As well as increasing gas production, optimal mixing can improve the energy efficiency of the anaerobic digestion process.

  20. Effect of aerobic and anaerobic exercises on glycemiccontrol in type 1 diabetic youths

    Institute of Scientific and Technical Information of China (English)

    Andrea Lukács; László Barkai

    2015-01-01

    AIM: To evaluate the long-term effect of aerobic and/ or anaerobic exercise on glycemic control in youths with type 1 diabetes. METHODS: Literature review was performed in spring and summer 2014 using PubMed/MEDLINE, Google Scholar, Scopus, and ScienceDirect with the following terms: aerobic, anaerobic, high-intensity, resistance, exercise/training, combined with glycemic/metabolic control, glycated haemoglobin A1c (HbA1c) and type 1 diabetes. Only peer-reviewed articles in English wereincluded published in the last 15 years. It was selectedfrom 1999 to 2014. Glycemic control was measuredwith HbA1c. Studies with an intervention lasting atleast 12 wk were included if the HbA1c was measuredbefore and after the intervention.RESULTS: A total of nine articles were found, andthey were published between the years of 2002-2011.The sample size was 401 diabetic youths (166 malesand 235 females) with an age range of 10-19 yearsexcept one study, in which the age range was 13-30years. Study participants were from Australia, Tunisia,Lithuania, Taiwan, Turkey, Brazilia, Belgium, Egypt andFrance. Four studies were aerobic-based, four werecombined aerobic and anaerobic programs, and onecompared aerobic exercise to anaerobic one. Availablestudies had insufficient evidence that any type ofexercise or combined training would clearly improvethe glycemic control in type 1 diabetic youth. Onlythree (two aerobic-based and one combined) studiescould provide a significant positive change in glycemiccontrol.CONCLUSION: The regular physical exercise hasseveral other valuable physiological and health benefitsthat justify the inclusion of exercise in pediatricdiabetes treatment and care.

  1. Effect of domestication on microorganism diversity and anaerobic digestion of food waste.

    Science.gov (United States)

    Bi, S J; Hong, X J; Wang, G X; Li, Y; Gao, Y M; Yan, L; Wang, Y J; Wang, W D

    2016-08-19

    To accomplish the rapid start-up and stable operation of biogas digesters, an efficient inoculum is required. To obtain such an inoculum for food waste anaerobic digestion, we domesticated dairy manure anaerobic digestion residue by adding food waste every day. After 36 days, the pH and biogas yield stabilized signifying the completion of domestication. During domestication, the microbial communities in the inocula were investigated by constructing 16S rDNA clone libraries. We evaluated the effect of the domesticated inoculum by testing batch food waste anaerobic digestion with a non-domesticated inoculum as a control. The pH and methane yield of the digestion systems were determined as measurement indices. Domestication changed the composition and proportion of bacteria and archaea in the inocula. Of the bacteria, Clostridia (49.3%), Bacteroidales (19.5%), and Anaerolinaceae (8.1%) species were dominant in the seed sludge; Anaerolinaceae (49.0%), Clostridia (28.4%), and Bacteroidales (9.1%), in domestication sludge. Methanosaeta was the dominant genus in both of the seed (94.3%) and domestication (74.3%) sludge. However, the diversity of methanogenic archaea was higher in the domestication than in seed sludge. Methanoculleus, which was absent from the seed sludge, appeared in the domestication sludge (21.7%). When the domesticated inoculum was used, the digestion system worked stably (organic loading rate: 20 gVS/L; methane yield: 292.2 ± 9.8 mL/gVS; VS = volatile solids), whereas the digestion system inoculated with seed sludge failed to generate biogas. The results indicate that inoculum domestication ensures efficient and stable anaerobic digestion by enriching the methanogenic strains.

  2. Effect of dietary arsonic acids on performance characteristics of swine waste anaerobic digesters

    Energy Technology Data Exchange (ETDEWEB)

    Brumm, M.C.; Sutton, A.L.; Jones, D.D.

    1980-01-01

    A completely random design experiment was conducted to determine the effect of dietary arsonic acids on the performance of laboratory swine waste anaerobic digesters. Fortified corn-soybean meal diets containing no arsonic acids (control), 100 ppm arsanilic acid or 75 ppm roxarsone were fed to growing-finishing pigs. Fresh waste (including urine) from all treatments were collected daily for 74 days and loaded at a rate of 2.4 kg volatile solids/cubic meter into nine 25-L anaerobic digesters heated to 34 degrees with continuous agitation and total gas collection. After a 60-day acclimation period, daily gas production and composition and nutrient composition data were obtained from the anaerobic digesters. Inclusion of the arsonic acids in swine diets reduced dry matter and volatile solids content. Dietary arsonic acids also increased NH4+-N. Alky. was high in all the digesters; however, arsonic acids decreased alky. Dietary arsonic acids reduced the ratio of CH4 to CO2 in the gas compared to the control. Significant amounts of As accumulated in the digesters. Alcohol, ethanol, and propanol concentrations were increased by roxarsone, and arsanilic acid increased the PrCO2H concentrations over the percentage in both the roxarsone and control digesters.

  3. Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure.

    Science.gov (United States)

    Arikan, Osman A; Mulbry, Walter; Lansing, Stephanie

    2015-09-01

    Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion. In temperate climates, digesters require a considerable amount of additional heat energy to maintain temperatures at these levels. In this study, the effects of lower digestion temperatures (22 and 28°C), on the methane production from dairy digesters were evaluated and compared with 35°C using duplicate replicates of field-scale (FS) digesters with a 17-day hydraulic retention time. After acclimation, the FS digesters were operated for 12weeks using solids-separated manure at an organic loading rate (OLR) of 1.4kgVSm(-3)d(-1) and then for 8weeks using separated manure amended with manure solids at an OLR of 2.6kgVSm(-3)d(-1). Methane production values of the FS digesters at 22 and 28°C were about 70% and 87%, respectively, of the values from FS digesters at 35°C. The results suggest that anaerobic digesters treating dairy manure at 28°C were nearly as efficient as digesters operated at 35°C, with 70% of total methane achievable at 22°C. These results are relevant to small farms interested in anaerobic digestion for methane reduction without heat recovery from generators or for methane recovery from covered lagoon digesters.

  4. Enhanced anaerobic treatment of CSTR-digested effluent from chicken manure: The effect of ammonia inhibition.

    Science.gov (United States)

    Liu, Zhan-Guang; Zhou, Xue-Fei; Zhang, Ya-Lei; Zhu, Hong-Guang

    2012-01-01

    The effect of ammonia inhibition was evaluated during the enhanced anaerobic treatment of digested effluent from a 700m(3) chicken-manure continuous stirred tank reactor (CSTR). A 12.3L internal circulation (IC) reactor inoculated with an anaerobic granular sludge and operated at 35±1°C was employed for the investigation. With a corresponding organic loading rate of 1.5-3.5kg-COD/m(3)d over a hydraulic retention time of 1.5d, a maximum volumetric biogas production rate of 1.2m(3)/m(3)d and TCOD (total COD) removal efficiency ranging from 70% to 80% was achieved. However, the continual increase in the influent TAN content led to ammonia inhibition in the methanogenesis system. The SCOD/TAN (soluble COD/total ammonia nitrogen) ratio was presented to be the key controlling factor for the anaerobic treatment of semi-digested chicken manure, and further validation through shock loading and ammonia inhibition experiments was conducted. The threshold value of the SCOD/TAN ratio was determined to be 2.4 (corresponding to a TAN of 1250mg/L) at an influent pH of 8.5-9.

  5. THE EFFECT OF F/M RATIO TO THE ANAEROBIC DECOMPOSITION OF BIOGAS PRODUCTION FROM FISH OFFAL WASTE

    Directory of Open Access Journals (Sweden)

    Agus Hadiyarto

    2016-01-01

    Full Text Available Biogas is a gas produced from the anaerobic decomposition of organic compounds. In the production of biogas from anaerobic digestion, value of F/M ratio shows a ratio between the mass of food available in the waste substrate with a mass of microorganisms that act as decomposers. F/M ratio is too small causing microbes could not metabolize perfectly and vice versa on the value of the ratio F / M overload resulting metabolic imbalance. The purpose of this study was to assess the effect of F/M ratio to optimal production of biogas from fish offal waste. The process of anaerobic digestion is conducted in the biodigester with four-liter volume and batch system operated at ambient temperature for 38 days. As a raw material, fish offal and microbial sludge obtained from the curing of fish and river mud discharges in the region of Bandarharjo, Semarang, Central Java. F/M ratio is set at 0.2, 0.4, and 0.6 are derived from sewage sludge VSS weight ratio of fish offal with sludge containing microbes. The addition of micronutrients supplied with a concentration of 0.4 mg/liter. Yield maximum methane gas obtained was 164,7 l/kg CODMn when the ratio F/M was 0.2. Based on the results of the study, found that the ratio F/M affect the amount of biogas produced. Meanwhile, the retention time (HRT is only influenced by the ratio F/M.

  6. ANAEROBIC DIGESTION OF ANIMAL WASTE: EFFECT OF MODE OF MIXING

    Science.gov (United States)

    Laboratory-scale digesters were operated to study the effect of mixing (via biogas recirculation, impeller mixing, and slurry recirculation) on biogas production. Three sets of experiments were performed using cow manure slurry feed with either 50, 100, or 150 g/L total solids (TS) concentrations (r...

  7. Synergistic and Pretreatment Effect on Anaerobic Co-Digestion from Rice Straw and Municipal Sewage Sludge

    Directory of Open Access Journals (Sweden)

    Mingxing Zhao

    2014-08-01

    Full Text Available Anaerobic digestion is considered to be a priority disposal technology for rice straw and sewage sludge. In this study, the synergistic and alkali-treat effect on co-digestion of rice straw and sewage sludge was investigated. The results indicated that the co-digestion of alkali-treated rice straw and sewage sludge had the best biogas yield of 338.9 mL/gVS, which was 1.06 and 1.75 times that of either alkali-treated rice straw or sewage sludge alone, respectively. The actual biogas and methane yields of a co-digestion group with raw rice straw and sewage sludge (G4 increased 26.39% and 24.79% relative to the theoretical calculation based on raw rice straw digestion (group G2 and sewage sludge digestion (group G5, suggesting that a synergistic effect occurred during the co-digestion process. The maximum concentration of volatile fatty acids (VFA was 4860 mg/L on the 4th day in the sewage sludge group. Xylanase activity reached a maximum of 10.55 U/mL on the 6th day in the alkali-treated rice straw group, while the concentration of protease enzyme was relatively higher in the sewage sludge group than in others. The removal rates of cellulose and hemicellulose in groups with alkali treatment were 32.25% and 36.96% (G1 and 40.86% and 41.61% (G3, higher than that of groups without treatment.

  8. A two-stage process for the anaerobic digestion of sludge generated during the production of bioethanol from sweet sorghum

    Energy Technology Data Exchange (ETDEWEB)

    Stamatelatou, K.; Dravillas, K.; Lyberatos, G.

    2003-07-01

    Sweet sorghum is an energy crop, often cultivated to recover energy in the form of ethanol, hydrogen etc by applying biological processes. These processes, however, produce a significant amount of sludge (bagasse) which contains the recalcitrant unconverted portion of sorghum, the non-hydrolyzed portion of the plant biomass as well as microbial biomass. In this work, the sludge from the alcoholic fermentation of sweet sorghum following a distillation step (to remove the generated bioethanol) was subjected to anaerobic digestion for further biodegradation and energy production (methane). A two-stage configuration for the anaerobic digestion of this type of industrial sludge was conceived and compared with a single stage anaerobic digestion of bagasse. For the two-stage process, the sludge was separated into one solid and one liquid stream. The solid portion of the sludge (9%) contributed mainly to the total organic load, although there was a significant organic load dissolved in the liquid portion too (28.73{+-}11.01 g/l). In the two stage system the solid and liquid phases of the sludge were separately treated under different operating conditions in two separate reactors: the solid phase in a thermophilic hydrolyzing reactor and the liquid phase in a mesophilic high-rate digester. The overall yield of the continuous two-stage process was 16 l methane/l wastewater at a hydraulic retention time of almost 20 days, while the maximum methane yield that could be achieved in batch experiments (duration 40d) was 30 l/l wastewater. (author)

  9. Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process

    DEFF Research Database (Denmark)

    Luo, Gang; Xie, Li; Zhou, Qi

    2011-01-01

    The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single......-stage methanogenic process (HRT 15d) under organic loading rate (OLR) 3gVS/(Ld). The two-stage process was still stable when the OLR was increased to 4.5gVS/(Ld), while the single-stage process failed. The study further revealed that by changing the HRThydrogen:HRTmethane ratio of the two-stage process from 3...

  10. Reuse of recalcitrant-rich anaerobic effluent as dilution water after enhancement of biodegradability by Fenton processes.

    Science.gov (United States)

    Arimi, Milton M; Zhang, Yongjun; Namango, Saul S; Geißen, Sven-Uwe

    2016-03-01

    Anaerobic digestion is used to treat effluents with a lot of organics, such as molasses distillery wastewater (MDW) which is the effluent of bioethanol production from molasses. The raw MDW requires a lot of dilution water before biodigestion, while the digested MDW has high level of recalcitrants which are problematic for its discharge. This study investigated ferric coagulation, Fenton, Fenton-like (with ferric ions as catalyst) processes and their combinations on the biodegradability of digested MDW. The Fenton and Fenton-like processes after coagulation increased the MDW biodegradability defined by (BOD5/COD) from 0.07 to (0.4-0.6) and saved 50% of H2O2 consumed in the classic Fenton process. The effluent from coagulation coupled to a Fenton-like process was used as dilution water for the raw MDW before the anaerobic digestion. The process was stable with volumetric loading of approx. 2.7 g COD/L/d. It resulted in increased overall biogas recovery and significantly decreased the demand for the dilution water.

  11. Formic Acid: Development of an Analytical Method and Use as Process Indicator in Anaerobic Systems

    Science.gov (United States)

    1992-03-01

    proteins . First these organic constituents are hydrolyzed and liquified by extracellular enzymes into a soluble form that can pass through the bacterial...organic matter. Mackie and Bryant (1990) correlated the rate of protein synthesis with cell growth and substrate degradation. Their purpose was to mrnitor...when it was added to anaerobic systems, it was rapidly depleted; in most cases in a matter of minutes. In a study of whey waste, Chartrain and Zeikus

  12. Nutrient removal from an anaerobic membrane bioreactor effluent using microalgae. Study and modeling of the process.

    OpenAIRE

    Ruiz Martínez, Ana

    2016-01-01

    [EN] Anaerobic membrane bioreactors for urban wastewater treatment present interesting advantages when compared with aerobic treatments, such as less sludge production, lower energy demand and biogas generation. However, the generated effluent cannot generally be discharged without further ammonium and phosphate elimination. This thesis studies the removal of these inorganic nutrients by means of microalgae cultivation. The main objective of this work is therefore to obtain an autochthono...

  13. Improved anaerobic digestion of a thermally pretreated mixture of physicochemical sludge; broiler excreta and sugar cane wastes (SCW): Effect on organic matter solubilization, biodegradability and bioenergy production.

    Science.gov (United States)

    Nava-Valente, Noemí; Alvarado-Lassman, Alejandro; Nativitas-Sandoval, Liliana S; Mendez-Contreras, Juan M

    2016-01-01

    Thermal pretreatment effect of a mixture of organic wastes (physicochemical sludge, excreta of broiler chickens and sugarcane wastes (SCW)) in the solubilization and biodegradability organic matter as well as bioenergy production by anaerobic digestion was evaluated. Two different mixtures of physicochemical sludge, excreta of broiler chickens and SCW (70%, 15%, 15% and 60%, 20%, 20% of VS, respectively) were treated at different temperatures (80 °C, 85 °C and 90 °C) and contact time (30, 60 and 90 min). Results indicate that, organic matter solubilization degree increased from 1.14 to 6.56%; subsequently, in the anaerobic digestion process, an increase of 50% in the volatile solids removal and 10% in biogas production was observed, while, retention time decreased from 23 up to 9 days. The results obtained were similar to pilot-scale. In both experimental scales it showed that the synergy produced by the simultaneous anaerobic digestion of different substrates could increase bioenergy production up to 1.3 L bio g(-1) VS removed and 0.82 L CH4 g(-1) VS removed. The treatment conditions presented in this study allow for large residue quantities to be treated and large bioenergy quantities to be produced (10% higher than during conventional treatment) without increasing the anaerobic digester volume.

  14. Effects of Dietary Acid Load on Exercise Metabolism and Anaerobic Exercise Performance

    Directory of Open Access Journals (Sweden)

    Susan L. Caciano, Cynthia L. Inman, Elizabeth E. Gockel-Blessing, Edward P. Weiss

    2015-06-01

    Full Text Available Dietary acid load, quantified as the potential renal acid load (PRAL of the diet, affects systemic pH and acid-base regulation. In a previous cross-sectional study, we reported that a low dietary PRAL (i.e. alkaline promoting diet is associated with higher respiratory exchange ratio (RER values during maximal exercise. The purpose of the present study was to confirm the previous findings with a short-term dietary intervention study. Additionally, we sought to determine if changes in PRAL affects submaximal exercise RER (as a reflection of substrate utilization and anaerobic exercise performance. Subjects underwent a graded treadmill exercise test (GXT to exhaustion and an anaerobic exercise performance test on two occasions, once after following a low-PRAL diet and on a separate occasion, after a high-PRAL diet. The diets were continued as long as needed to achieve an alkaline or acid fasted morning urine pH, respectively, with all being 4-9 days in duration. RER was measured during the GXT with indirect calorimetry. The anaerobic performance test was a running time-to-exhaustion test lasting 1-4 min. Maximal exercise RER was lower in the low-PRAL trial compared to the high-PRAL trial (1.10 ± 0.02 vs. 1.20 ± 0.05, p = 0.037. The low-PRAL diet also resulted in a 21% greater time to exhaustion during anaerobic exercise (2.56 ± 0.36 vs. 2.11 ± 0.31 sec, p = 0.044 and a strong tendency for lower RER values during submaximal exercise at 70% VO2max (0.88 ± 0.02 vs. 0.96 ± 0.04, p = 0.060. Contrary to our expectations, a short-term low-PRAL (alkaline promoting diet resulted in lower RER values during maximal-intensity exercise. However, the low-PRAL diet also increased anaerobic exercise time to exhaustion and appears to have shifted submaximal exercise substrate utilization to favor lipid oxidation and spare carbohydrate, both of which would be considered favorable effects in the context of exercise performance.

  15. A study of the process of two staged anaerobic fermentation as a possible method for purifying sewage

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y.; Kouama, K.; Matsuo, T.

    1983-01-01

    Great attention has recently been given to the study of the processes of anaerobic fermentation, which may become alternatives to the existing methods for purifying waste waters which use aerobic microorganisms. A series of experimentswere conducted with the use of an artificially prepared liquid (fermented milk and starch) which imitates the waste to be purified, in order to explain the capabilities of the process of two staged anaerobic fermentation (DAS) as a method for purifying waste waters. The industrial system of the process includes: a fermentation vat for acetic fermentation with recirculation of the sediment, a primary settler, a fermentation tank for methane fermentation and a secondary settler. The process was conducted at a loading speed (based on Carbon) from 0.15 to 0.4 kilograms per cubic meter per day at a temperature of 38C. The degree of conversion of the fermented organic substances into volatile organic acids was not a function of the loading speed and was 54 to 57 percent in the acetic fermentation tank, where 95 to 97 percent of the organic material was broken down with the production of methane and carbon dioxide.

  16. Effect of natural zeolite on methane production for anaerobic digestion of ammonium rich organic sludge.

    Science.gov (United States)

    Tada, Chika; Yang, Yingnan; Hanaoka, Toshiaki; Sonoda, Akinari; Ooi, Kenta; Sawayama, Shigeki

    2005-03-01

    The effect of an inorganic additive on the methane production from NH(4+)-rich organic sludge during anaerobic digestion was investigated using different kinds of inorganic adsorbent zeolites (mordenite, clinoptilolite, zeolite 3A, zeolite 4A), clay mineral (vermiculite), and manganese oxides (hollandite, birnessite). The additions of inorganic materials resulted in significant NH4+ removals from the natural organic sludge ([NH4+]=1, 150 mg N/l), except for the H-type zeolite 3A and birnessite. However, an enhanced methane production was only achieved using natural mordenite. Natural mordenite also enhanced the methane production from the sludge with a markedly high NH4+ concentration (4500 mg N/l) during anaerobic digestion. Chemical analyses of the sludge after the digestion showed considerable increases in the Ca2+ and Mg2+ concentrations in the presence of natural mordenite, but not with synthetic zeolite 3A. The effect of Ca2+ or Mg2+ addition on the methane production was studied using Na(+)-exchanges mordenite and Ca2+ or Mg(2+)-enriched sludge. The simultaneous addition of Ca2+ ions and Na(+)-exchanged mordenite enhanced the methane production; the amount of produced methane was about three times greater than that using only the Na(+)-exchanged mordenite. In addition, comparing the methane production by the addition of natural mordenite or Ca2+ ions, the methane production with natural mordenite was about 1.7 times higher than that with only Ca2+ ions. The addition of 5% and 10% natural mordenite were suitable condition for obtaining a high methane production. These results indicated that the Ca2+ ions, which are released from natural mordenite by a Ca2+/NH4+ exchange, enhanced the methane production of the organic waste at a high NH4+ concentration. Natural mordenite has a synergistic effect on the Ca2+ supply as well on the NH4+ removal during anaerobic digestion, which is effective for the mitigation of NH4+ inhibition against methane production.

  17. Evaluation of methane generation and process stability from anaerobic co-digestion of sugar beet by-product and cow manure.

    Science.gov (United States)

    Aboudi, Kaoutar; Álvarez-Gallego, Carlos José; Romero-García, Luis Isidoro

    2016-05-01

    The effect of mesophilic anaerobic co-digestion of dried pellets of exhausted sugar beet cossettes (ESBC-DP) and cow manure (CM) on the enhancement of methane generation and process stability were studied with the aim to select the best substrate mixture ratio. A series of batch experiments was conducted using the following five mixture ratios of ESBC-DP:CM: 0:100; 25:75; 50:50; 75:25 and 100:0. Best results were obtained from mixture ratios with ESBC-DP proportions in the range of 25-50%. Mixture ratio of 50:50 showed a specific methane production (SMP) increase of 81.4% and 25.5%, respectively, in comparison with mono-digestion of ESBC-DP and CM. Evolution of the indirect parameter named acidogenic substrate as carbon (ASC) could be used to provide more insight about the process stability of anaerobic digestion. ASC accumulation was observed in reactors with higher ESBC-DP proportions leading to a delay in VFAs consumption and conversion into methane.

  18. Determination of some aliphatic carboxylic acids in anaerobic digestion process waters by ion-exclusion chromatography with conductimetric detection on a weakly acidic cation-exchange resin column.

    Science.gov (United States)

    Ito, Kazuaki; Takayama, Yohichi; Ikedo, Mikaru; Mori, Masanobu; Taoda, Hiroshi; Xu, Qun; Hu, Wenzhi; Sunahara, Hiroshi; Hayashi, Tsuneo; Sato, Shinji; Hirokawa, Takeshi; Tanaka, Kazuhiko

    2004-06-11

    The determination of seven aliphatic carboxylic acids, formic, acetic, propionic, isobutyric, n-butyric, isovaleric and n-valeric acids in anaerobic digestion process waters was examined using ion-exclusion chromatography with conductimetric detection. The analysis of these biologically important carboxylic acids is necessary as a measure for evaluating and controlling the process. The ion-exclusion chromatography system employed consisted of polymethacrylate-based weakly acidic cation-exchange resin columns (TSKgel OApak-A or TSKgel Super IC-A/C). weakly acidic eluent (benzoic acid), and conductimetric detection. Particle size and cation-exchange capacity were 5 microm and 0.1 meq./ml for TSKgel OApak-A and 3 microm and 0.2 meq./ml for TSKgel Super IC-A/C, respectively. A dilute eluent (1.0-2.0 mM) of benzoic acid was effective for the high resolution and highly conductimetric detection of the carboxylic acids. The good separation of isobutyric and n-butyric acids was performed using the TSKgel Super IC-A/C column (150 mm x 6.0 mm i.d. x 2). The simple and good chromatograms were obtained by the optimized ion-exclusion chromatography conditions for real samples from mesophilic anaerobic digestors, thus the aliphatic carboxylic acids were successfully determined without any interferences.

  19. Effect of chlorate, molybdate, and shikimic acid on Salmonella enterica serovar Typhimurium in aerobic and anaerobic cultures.

    Science.gov (United States)

    Oliver, Christy E; Beier, Ross C; Hume, Michael E; Horrocks, Shane M; Casey, Thomas A; Caton, Joel S; Nisbet, David J; Smith, David J; Krueger, Nathan A; Anderson, Robin C

    2010-04-01

    Experiments were conducted to determine factors that affect sensitivity of Salmonella enterica serovar Typhimurium to sodium chlorate (5mM). In our first experiment, cultures grown without chlorate grew more rapidly than those with chlorate. An extended lag before logarithmic growth was observed in anaerobic but not aerobic cultures containing chlorate. Chlorate inhibition of growth during aerobic culture began later than that observed in anaerobic cultures but persisted once inhibition was apparent. Conversely, anaerobic cultures appeared to adapt to chlorate after approximately 10h of incubation, exhibiting rapid compensatory growth. In anaerobic chlorate-containing cultures, 20% of total viable counts were resistant to chlorate by 6h and had propagated to 100% resistance (>10(9)CFU mL(-1)) by 24h. In the aerobic chlorate-containing cultures, 12.9% of colonies had detectable resistance to chlorate by 6h, but only 1% retained detectable resistance at 24h, likely because these cultures had opportunity to respire on oxygen and were thus not enriched via the selective pressure of chlorate. In another study, treatment with shikimic acid (0.34 mM), molybdate (1mM) or their combination had little effect on aerobic or anaerobic growth of Salmonella in the absence of added chlorate. As observed in our earlier study, chlorate resistance was not detected in any cultures without added chlorate. Chlorate resistant Salmonella were recovered at equivalent numbers regardless of treatment after 8h of aerobic or anaerobic culture with added chlorate; however, by 24h incubation chlorate sensitivity was completely restored to aerobic but not anaerobic cultures treated with shikimic acid or molybdate but not their combination. Results indicate that anaerobic adaptation of S. Typhimurium to sodium chlorate during pure culture is likely due to the selective propagation of low numbers of cells exhibiting spontaneous resistance to chlorate and this resistance is not reversible by

  20. The influence of the temperature regime on the formation of methane in a two-phase anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, Mandy; Linke, Bernd

    2012-06-15

    The influence of different temperature levels on the formation of methane in a two-phase anaerobic digestion process using rye silage and barley straw as feedstocks was investigated in this study. This process comprised a leach-bed reactor (LBR), a reservoir for leachate from the LBR, and a separate downstream fixed-film anaerobic filter (AF), with immobilized micro biocoenosises. The degree of degradation of the volatile solids was similar in both studies and was almost equal at 75 Ma.-%{sub VS}. When both reactor phases were operated at thermophilic conditions, the main substrate turnover was observed in the LBR(58% of the total methane yield, with an average methane content of 41 Vol.-%). Only the excess of organic fraction in the process-liquid was transformed in the AF(42% of the total methane yield, with an average methane content of 74 Vol.-%). When the parts of the reactor system operated at different temperature regimes, thermophilic hydrolysis/acidogenesis phase and mesophilic methanization, a separation of carbon dioxide and methane production, was observed. A total methane yield of 88%, with an average methane content of 85 Vol.-%, was formed in the AF. The generated biogas with high methane concentrations is suitable for feeding the purified biomethane into the natural gas grid. Furthermore, it can be used as fuel for cars and tractors. (copyright 2012 WILEY-VCH Verlag GmbH 8 Co. KGaA, Weinheim)

  1. High-Rate Anaerobic Side-Stream Reactor (ASSR) Processes to Minimize the Production of Excess Sludge.

    Science.gov (United States)

    Park, Chul; Chon, Dong-Hyun

    2015-12-01

    High-rate anaerobic side-stream reactor (ASSR) processes were developed to minimize excess sludge production during wastewater treatment. New ASSRs were operated in 2.5-day solids retention time (SRT), much shorter than 10-day SRT used by the commercial sludge reduction process. The 2.5-day was selected based on literature review and preliminary studies, showing that maximum solublization of key floc components, such as divalent cations, extracellular polymeric substances (EPS), and protease, occur within 2 to 3 days of anaerobic digestion. The laboratory reactor study showed that 2.5-day ASSR systems produced approximately 60 and 20% less sludge than the control (no ASSR) and the 10-day ASSR, respectively. The experimental systems showed acceptable effluent quality, despite minimal sludge wastage. This was possible because sludge EPS were continuously released/degraded and regenerated as sludge underwent recirculation between ASSR and the aerobic basin. The results supported that the activated sludge process incorporating small ASSRs significantly decrease the production of excess sludge during wastewater treatment.

  2. A hybrid cascade control scheme for the VFA and COD regulation in two-stage anaerobic digestion processes.

    Science.gov (United States)

    Méndez-Acosta, H O; Campos-Rodríguez, A; González-Álvarez, V; García-Sandoval, J P; Snell-Castro, R; Latrille, E

    2016-10-01

    A hybrid (continuous-discrete) cascade control is proposed to regulate both, volatile fatty acids (VFA) and chemical oxygen demand (COD) concentrations in two-stage (acidogenic-methanogenic) anaerobic digestion (TSAD) processes. The outer loop is a discrete controller that regulates the COD concentration of the methanogenic bioreactor by using a daily off-line measurement and that modifies the set-point tracked by inner loop, which manipulates the dilution rate to regulate the VFA concentration of the acidogenic bioreactor, estimated by continuous on-line conductivity measurements, avoiding acidification. The experimental validation was conducted in a TSAD process for the treatment of tequila vinasses during 110days. Results showed that the proposed cascade control scheme was able to achieve the VFA and COD regulation by using conventional measurements under different set-point values in spite of adverse common scenarios in full-scale anaerobic digestion processes. Microbial composition analysis showed that the controller also favors the abundance and diversity toward methane production.

  3. Increasing biogas production from sewage sludge anaerobic co-digestion process by adding crude glycerol from biodiesel industry.

    Science.gov (United States)

    Nartker, Steven; Ammerman, Michelle; Aurandt, Jennifer; Stogsdil, Michael; Hayden, Olivia; Antle, Chad

    2014-12-01

    In an effort to convert waste streams to energy in a green process, glycerol from biodiesel manufacturing has been used to increase the gas production and methane content of biogas within a mesophilic anaerobic co-digestion process using primary sewage sludge. Glycerol was systematically added to the primary digester from 0% to 60% of the organic loading rate (OLR). The optimum glycerol loading range was from 25% to 60% OLR. This resulted in an 82-280% improvement in specific gas production. Following the feeding schedule described, the digesters remained balanced and healthy until inhibition was achieved at 70% glycerol OLR. This suggests that high glycerol loadings are possible if slow additions are upheld in order to allow the bacterial community to adjust properly. Waste water treatment plant operators with anaerobic digesters can use the data to increase loadings and boost biogas production to enhance energy conversion. This process provides a safe, environmentally friendly method to convert a typical waste stream to an energy stream of biogas.

  4. 厌氧MBBR处理生活污水的特性研究%Research on domestic wastewater treatment by anaerobic MBBR process

    Institute of Scientific and Technical Information of China (English)

    赵建邦; 袁辉洲; 柯水洲

    2011-01-01

    采用厌氧移动床生物膜反应器处理城市生活污水,研究了HRT、pH值、容积负荷、水温等对工艺运行效果的影响,并进行了厌氧MBBR与SBR联用试验及回用分析.结果表明,在HRT为4 h,进水CODCr的质量浓度为300mg/L左右,氨氮的质量浓度为15 mg/L左右,50%的填料填充率,pH值为7左右的条件下,厌氧MBBR出水CODCr、氨氮、总磷指标达到了GB 18918-2002二级标准;厌氧MBBR与SBR联用处理出水满足GB/T18920-2002,且达到了HG/T 3923-2007.%Anaerobic MBBR was used to treat urban domestic wastewater, the influences of HRT, pH value,volume loading, water temperature and some other factors on treatment effect were studied, and an anaerobic MBBR-SBR combined experiment was carried out with water recycling analyzed. The results showed that, when the HRT was 4 h, the mass concentrations of CODCr and ammonia nitrogen in the infiuent water were about 300 and 15 mg/L respectively, the filling rate was 50%, the pH value was 7, the mass concentrations of CODCr,ammonia nitrogen and total phosphorus in the effluent water treated by the anaerobic MBBR process met the specification for grade 2 in GB 18918-2002 Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant. The quality of the effluent water treated by the anaerobic MBBR-SBR combined process could meet the requirements of GB/T 18920-2002 The Reuse of Urban Recycling Water-Water Quality Standard For Urban Miscellaneous Water Consumption and HG/T 3923-2007 Reusing Wastewater Quality Standard for Industrial Circulating Cooling Water at the same time.

  5. Modelling phosphorus (P), sulfur (S) and iron (Fe) interactions for dynamic simulations of anaerobic digestion processes.

    Science.gov (United States)

    Flores-Alsina, Xavier; Solon, Kimberly; Kazadi Mbamba, Christian; Tait, Stephan; Gernaey, Krist V; Jeppsson, Ulf; Batstone, Damien J

    2016-05-15

    This paper proposes a series of extensions to functionally upgrade the IWA Anaerobic Digestion Model No. 1 (ADM1) to allow for plant-wide phosphorus (P) simulation. The close interplay between the P, sulfur (S) and iron (Fe) cycles requires a substantial (and unavoidable) increase in model complexity due to the involved three-phase physico-chemical and biological transformations. The ADM1 version, implemented in the plant-wide context provided by the Benchmark Simulation Model No. 2 (BSM2), is used as the basic platform (A0). Three different model extensions (A1, A2, A3) are implemented, simulated and evaluated. The first extension (A1) considers P transformations by accounting for the kinetic decay of polyphosphates (XPP) and potential uptake of volatile fatty acids (VFA) to produce polyhydroxyalkanoates (XPHA) by phosphorus accumulating organisms (XPAO). Two variant extensions (A2,1/A2,2) describe biological production of sulfides (SIS) by means of sulfate reducing bacteria (XSRB) utilising hydrogen only (autolithotrophically) or hydrogen plus organic acids (heterorganotrophically) as electron sources, respectively. These two approaches also consider a potential hydrogen sulfide ( [Formula: see text] inhibition effect and stripping to the gas phase ( [Formula: see text] ). The third extension (A3) accounts for chemical iron (III) ( [Formula: see text] ) reduction to iron (II) ( [Formula: see text] ) using hydrogen ( [Formula: see text] ) and sulfides (SIS) as electron donors. A set of pre/post interfaces between the Activated Sludge Model No. 2d (ASM2d) and ADM1 are furthermore proposed in order to allow for plant-wide (model-based) analysis and study of the interactions between the water and sludge lines. Simulation (A1 - A3) results show that the ratio between soluble/particulate P compounds strongly depends on the pH and cationic load, which determines the capacity to form (or not) precipitation products. Implementations A1 and A2,1/A2,2 lead to a reduction in

  6. Volatile fatty acid degradation kinetics in anaerobic process; Cinetica de la degradacion de acidos grasos volatiles en procesos anaerobios

    Energy Technology Data Exchange (ETDEWEB)

    Riscado, S.; Osuna, B.; Iza, J.; Ruiz, E. [Universidad del Pais Vasco. Bilbao (Spain)

    1998-10-01

    While searching for the optimal substrate load for anaerobic toxicity assays, the inhibition caused by the propionic acid has been addressed. Lab scale experiments have been carried out to assess the effects of different loads and acid ratios. Results bad been subjected to kinetic analysis and show the degradation follows a first order kinetic, and acetic is easier to degrade than propionic acid. The optimal load for a 100 ml vial assay is composed of 158 mg COD of the 3:1:1 HAc:HPr:HBu mixture. (Author) 9 refs.

  7. The effects of the antibiotics ampicillin, florfenicol, sulfamethazine, and tylosin on biogas production and their degradation efficiency during anaerobic digestion.

    Science.gov (United States)

    Mitchell, Shannon M; Ullman, Jeffrey L; Teel, Amy L; Watts, Richard J; Frear, Craig

    2013-12-01

    The impacts of four common animal husbandry antibiotics (ampicillin, florfenicol, sulfamethazine, and tylosin) on anaerobic digestion (AD) treatment efficiency and the potential for antibiotic degradation during digestion were evaluated. Sulfamethazine and ampicillin exhibited no impact on total biogas production up to 280 and 350 mg/L, respectively, although ampicillin inhibited biogas production rates during early stages of AD. Tylosin reduced biogas production by 10-38% between 130 and 913 mg/L. Florfenicol reduced biogas by ≈ 5%, 40% and 75% at 6.4, 36 and 210 mg/L, respectively. These antibiotic concentrations are higher than commonly seen for mixed feedlot manure, so impacts on full scale AD should be minimal. Antibiotic degradation products were found, confirming AD effectively degraded ampicillin, florfenicol, and tylosin, although some products were persistent throughout the process. Contamination of AD solid and liquid effluents with sulfamethazine and antibiotic transformation products from florfenicol and tylosin could present an environmental concern.

  8. Effect of thermal treatment of anaerobic sludge on the bioavailability and biodegradability characteristics of the organic fraction

    Directory of Open Access Journals (Sweden)

    E. S. M. Borges

    2009-09-01

    Full Text Available Most works reported in the literature focus on thermal treatment of waste activated sludge at temperatures in the range of 160 to 180ºC. This research aimed at evaluating the thermal treatment of excess anaerobic sludge at much lower temperatures, using biogas generated in the wastewater treatment process as the energy source for heating a simplified thermal reactor. Direct burning of the biogas allowed an increase in the sludge temperature up to values close to 75ºC, for a 7-hour heating period. Sludge samples taken at different heating times showed that the thermal disintegration of the organic fraction allowed increases in the concentration of protein, carbohydrate, lipid and COD parameters by 30 to 35 times, as well as a 50% increase in the biogas production. Moreover, the simplified thermal treatment system proved to be an effective alternative for recovering energy from biogas and for controlling methane emissions to the atmosphere.

  9. Effect of different ratios of cow manure and corn straw on the mixed anaerobic fermentation rate

    Directory of Open Access Journals (Sweden)

    Zongshan JIANG

    2016-08-01

    Full Text Available In order to study the effect of the different ratios on the anaerobic fermentation rate is investigated, and the rate-limiting factors are preliminarily determined, at mesophilic (38±1℃ condition, with anaerobic granular sludge as inoculums, different ratios of cow manure and corn straw are used as substrate for mixed anaerobic fermentation. By measuring daily biogas production, the concentrations of CH4 and CO2 in the marsh gas, TC, the concentration of VFAs and pH value, The results show that under the mixture ratio of 2∶1, the hydrolysis rate constants, cumulative biogas yield and biodegradability CH4 reach their high limits, which are 0.043 7 d-1, 271.93 mL/g and 71.59%, respectively. Moreover, it is found that the concentration of acetic acid is proportional to the amount of cow manure at the beginning (the first day of mixed fermentation, and the concentration of propionicacid is proportional to the amount of corn straw in medium fermentation stage (the fifth day. In addition, rate-limiting step of biogas production is related to the ratio of cow manure and corn in fermentation material. With the increasing of corn straw proportion, on the 1st day, it tends to hydrolysis acidogenesis; from the 2th day to 15th day, it tends to hydrogen-production acetogenisis; and from the 16th day to 30th day, it is hydrolysis acidogenesis. The paper focuses on the relationship between the ratio of cow manure and corn straw and the rate-limiting step for biogas production, which could provide a theoretical and experimental support for improving the efficiency of biogas production in mixed fermentation.

  10. Integrated extraction and anaerobic digestion process for recovery of nutraceuticals and biogas from pomegranate marcs

    Science.gov (United States)

    Pomegranate marc (PM), a by-product from pomegranate juice processing, has not been effectively utilized. The objectives of this study were to (1) determine the yields and properties of antioxidants (henceforth referring to total phenolics in terms of tannic acid equivalent) and oil extracted from v...

  11. The effects of polyethylene glycosylated creatine supplementation on anaerobic performance measures and body composition.

    Science.gov (United States)

    Camic, Clayton L; Housh, Terry J; Zuniga, Jorge M; Traylor, Daniel A; Bergstrom, Haley C; Schmidt, Richard J; Johnson, Glen O; Housh, Dona J

    2014-03-01

    The purpose of this study was to examine the effects of 28 days of polyethylene glycosylated creatine (PEG-creatine) supplementation (1.25 and 2.50 g·d) on anaerobic performance measures (vertical and broad jumps, 40-yard dash, 20-yard shuttle run, and 3-cone drill), upper- and lower-body muscular strength and endurance (bench press and leg extension), and body composition. This study used a randomized, double-blind, placebo-controlled parallel design. Seventy-seven adult men (mean age ± SD, 22.1 ± 2.5 years; body mass, 81.7 ± 10.8 kg) volunteered to participate and were randomly assigned to a placebo (n = 23), 1.25 g·d of PEG-creatine (n = 27), or 2.50 g·d of PEG-creatine (n = 27) group. The subjects performed anaerobic performance measures, muscular strength (one-repetition maximum [1RM]), and endurance (80% 1RM) tests for bench press and leg extension, and underwater weighing for the determination of body composition at day 0 (baseline), day 14, and day 28. The results indicated that there were improvements (p creatine groups without changes for the placebo group. Thus, the present results demonstrated that PEG-creatine supplementation at 1.25 or 2.50 g·d had an ergogenic effect on lower-body vertical power, agility, change-of-direction ability, upper-body muscular endurance, and body mass.

  12. Production of methane from sugar beet silage without manure addition by a single-stage anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, B.; Scherer, P. [Lifetec Process Engineering, Faculty of Life Sciences, Hamburg University of Applied Sciences, Lohbruegger Kirchstrasse 65, 21033 Hamburg (Germany)

    2008-03-15

    Single-stage continuous anaerobic conversion of sugar beet silage without manure to methane was investigated in this experimental work, using a laboratory-scale mesophilic anaerobic biogas digester. The sugar beet silage had an extreme low pH of 3.3. The reactor was operated in a hydraulic retention time (HRT) range of between 95 and 15 days, and an organic loading rate (OLR) range of between 0.937 and 6.33 g{sup -1} VS l{sup -1} d{sup -1}. The highest specific gas production rate (spec. GPR) of 0.72 l g VS{sup -1} d{sup -1} could be obtained at 25 days of HRT, with an average methane content of about 63%, at a pH of around 6.8. Since sugar beet silage without the leaves is a poor substrate, in terms of the availability of the nutrients and the buffering capacity, external supplementation of nitrogen and buffering agents has to be regularly performed, in order to achieve a stable and an efficient process. Sodium or potassium hydrogen carbonate addition seemed to function best in our case, among the other agents used, to provide adequate buffering capacity and to keep the digester pH stable during the operation. Use of a new harvest (a new charge of substrate) also affected the spec. GPR values significantly. (author)

  13. Effects of caffeine on time to exhaustion in exercise performed below and above the anaerobic threshold

    Directory of Open Access Journals (Sweden)

    Denadai B.S.

    1998-01-01

    Full Text Available Controversy still exists concerning the potential ergogenic benefit of caffeine (CAF for exercise performance. The purpose of this study was to compare the effects of CAF ingestion on endurance performance during exercise on a bicycle ergometer at two different intensities, i.e., approximately 10% below and 10% above the anaerobic threshold (AT. Eight untrained males, non-regular consumers of CAF, participated in this study. AT, defined as the intensity (watts corresponding to a lactate concentration of 4 mM, was determined during an incremental exercise test from rest to exhaustion on an electrically braked cycle ergometer. On the basis of these measurements, the subjects were asked to cycle until exhaustion at two different intensities, i.e., approximately 10% below and 10% above AT. Each intensity was performed twice in a double-blind randomized order by ingesting either CAF (5 mg/kg or a placebo (PLA 60 min prior to the test. Venous blood was analyzed for free fatty acid, glucose, and lactate, before, during, and immediately after exercise. Rating of perceived exertion and time to exhaustion were also measured during each trial. There were no differences in free fatty acids or lactate levels between CAF and PLA during and immediately after exercise for either intensity. Immediately after exercise glucose increased in the CAF trial at both intensities. Rating of perceived exertion was significantly lower (CAF = 14.1 ± 2.5 vs PLA = 16.6 ± 2.4 and time to exhaustion was significantly higher (CAF = 46.54 ± 8.05 min vs PLA = 32.42 ± 14.81 min during exercise below AT with CAF. However, there was no effect of CAF treatment on rating of perceived exertion (CAF = 18.0 ± 2.7 vs PLA = 17.6 ± 2.3 and time to exhaustion (CAF = 18.45 ± 7.28 min vs PLA = 19.17 ± 4.37 min during exercise above AT. We conclude that in untrained subjects caffeine can improve endurance performance during prolonged exercise performed below AT and that the decrease of

  14. Modelling phosphorus (P), sulfur (S) and iron (Fe) interactions for dynamic simulations of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores Alsina, Xavier; Solon, Kimberly; Kazadi Mbamba, Christian

    2016-01-01

    This paper proposes a series of extensions to functionally upgrade the IWA Anaerobic Digestion Model No. 1 (ADM1) to allow for plant-wide phosphorus (P) simulation. The close interplay between the P, sulfur (S) and iron (Fe) cycles requires a substantial (and unavoidable) increase in model...... complexity due to the involved three-phase physico-chemical and biological transformations. The ADM1 version, implemented in the plant-wide context provided by the Benchmark Simulation Model No. 2 (BSM2), is used as the basic platform (A0). Three different model extensions (A1, A2, A3) are implemented......, simulated and evaluated. The first extension (A1) considers P transformations by accounting for the kinetic decay of polyphosphates (XPP) and potential uptake of volatile fatty acids (VFA) to produce polyhydroxyalkanoates (XPHA) by phosphorus accumulating organisms (XPAO). Two variant extensions (A2,1/A2...

  15. Modified two-phase anaerobic baffled process for low-concentration wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    LIN Ying-zi; HAN Xiang-kui; YIN Jun; SHAO Pi-hong; AI Sheng-shu

    2009-01-01

    In this study low-concentration wastewater was investigated in the integral two-phase anaerobic baf-fled reactor by determining the removal of COD at various HRT,reflex ratios,and temperatures.Results indi-cate that the removal efficiency of COD is more than 90%at 25℃and 10-h HRT with no wastewater recycled,and the removal efficiency is up to 88%at 8-h HRT and reflex ratio of 150%.The removal efficiency is de-creased with the decreasing temperature and HRT.The removal efficiency of COD is approximaleIy 60%at10℃,which proves that the temperature does not affect it apparently.This research has significance for reduc-ing the cost ot wastewater and sludge treatment in cold area.

  16. Optimization of Anaerobic Digestion of Cattle Manure. Effect of its Association with the Aquatic Weed Pistia (Pistia stratiotes

    Directory of Open Access Journals (Sweden)

    Zennaki, Z.

    1997-01-01

    Full Text Available This study investigates the improvement of performance of anaerobic fermentation of cattle manure mixed with the water lettuce Pistia stratiotes, a macrophyte plant growing in the effluent of an anaerobic digestor. The experiments used a series of continuous fermentors, using mixtures of cattle manure and water lettuce in the following proportions : 12.5 %, 16.6 %, 25 % and 50 % of Pistia stratiotes. The best biogas yields were achieved with a proportion of 50 % of water lettuce in the mixture giving a biogas yield of 0.62 m3/(m3. d. with a methane content of 76.8 % over a 15-days hydraulic retention time, at a constant temperature of 35° C. The kinetic study based on batch fermentation shows that the process is well represented by the Monod Model. These performances are better than those obtained in anaerobic digestion of cattle manure used alone.

  17. Anaerobic Digestion and Biogas Potential: Simulation of Lab and Industrial-Scale Processes

    Directory of Open Access Journals (Sweden)

    Ihsan Hamawand

    2015-01-01

    Full Text Available In this study, a simulation was carried out using BioWin 3.1 to test the capability of the software to predict the biogas potential for two different anaerobic systems. The two scenarios included: (1 a laboratory-scale batch reactor; and (2 an industrial-scale anaerobic continuous lagoon digester. The measured data related to the operating conditions, the reactor design parameters and the chemical properties of influent wastewater were entered into BioWin. A sensitivity analysis was carried out to identify the sensitivity of the most important default parameters in the software’s models. BioWin was then calibrated by matching the predicted data with measured data and used to simulate other parameters that were unmeasured or deemed uncertain. In addition, statistical analyses were carried out using evaluation indices, such as the coefficient of determination (R-squared, the correlation coefficient (r and its significance (p-value, the general standard deviation (SD and the Willmott index of agreement, to evaluate the agreement between the software prediction and the measured data. The results have shown that after calibration, BioWin can be used reliably to simulate both small-scale batch reactors and industrial-scale digesters with a mean absolute percentage error (MAPE of less than 10% and very good values of the indexes. Furthermore, by changing the default parameters in BioWin, which is a way of calibrating the models in the software, as well, this may provide information about the performance of the digester. Furthermore, the results of this study showed there may be an over estimation for biogas generated from industrial-scale digesters. More sophisticated analytical devices may be required for reliable measurements of biogas quality and quantity.

  18. Effects of intermittent training on anaerobic performance and MCT transporters in athletes.

    Directory of Open Access Journals (Sweden)

    Grégoire Millet

    Full Text Available This study examined the effects of intermittent hypoxic training (IHT on skeletal muscle monocarboxylate lactate transporter (MCT expression and anaerobic performance in trained athletes. Cyclists were assigned to two interventions, either normoxic (N; n = 8; 150 mmHg PIO2 or hypoxic (H; n = 10; ∼3000 m, 100 mmHg PIO2 over a three week training (5×1 h-1h30 x week(-1 period. Prior to and after training, an incremental exercise test to exhaustion (EXT was performed in normoxia together with a 2 min time trial (TT. Biopsy samples from the vastus lateralis were analyzed for MCT1 and MCT4 using immuno-blotting techniques. The peak power output (PPO increased (p<0.05 after training (7.2% and 6.6% for N and H, respectively, but VO2max showed no significant change. The average power output in the TT improved significantly (7.3% and 6.4% for N and H, respectively. No differences were found in MCT1 and MCT4 protein content, before and after the training in either the N or H group. These results indicate there are no additional benefits of IHT when compared to similar normoxic training. Hence, the addition of the hypoxic stimulus on anaerobic performance or MCT expression after a three-week training period is ineffective.

  19. Effect of chemo-mechanical disintegration on sludge anaerobic digestion for enhanced biogas production.

    Science.gov (United States)

    Kavitha, S; Pray, S Saji; Yogalakshmi, K N; Kumar, S Adish; Yeom, Ick-Tae; Banu, J Rajesh

    2016-02-01

    The effect of combined surfactant-dispersion pretreatment on dairy waste activated sludge (WAS) reduction in anaerobic digesters was investigated. The experiments were performed with surfactant, Sodium dodecyl sulfate (SDS) in the range of 0.01 to 0.1 g/g suspended solids (SS) and disperser with rpm of 5000-25,000. The COD (chemical oxygen demand) solubilization, suspended solids reduction, and biogas generation increased for an energy input of 7377 kJ/kg total solids (TS) (12,000 rpm, 0.04 g/g SS, and 30 min) and were found to be 38, 32, and 75 %, higher than that of control. The pretreated sludge improved the performance of semicontinuous anaerobic digesters of 4 L working volume operated at four different SRTs (sludge retention time). SRT of 15 days was found to be appropriate showing 49 and 51 % reduction in SS and volatile solids (VS), respectively. The methane yield of the pretreated sample was observed to be 50 mL/g VS removed which was observed to be comparatively higher than the control (12 mL/g VS removed) at optimal SRT of 15 days. To the best of the authors' knowledge, this study is the first to be reported and not yet been documented in literature.

  20. pH Control for Effective Anaerobic Bioremediation of Chlorinated Solvents

    Science.gov (United States)

    Robinson, C.; Barry, D.; Gerhard, J. I.; Kouznetsova, I.

    2007-12-01

    SABRE (Source Area BioREmediation) is a 4-year collaborative project that aims to evaluate the performance of enhanced anaerobic bioremediation for the treatment of chlorinated solvent DNAPL source areas. The project focuses on a pilot scale demonstration at a trichloroethene (TCE) DNAPL field site, and includes complementary laboratory and modelling studies. Organic acids and hydrogen ions (HCl) typically build up in the treatment zone during anaerobic bioremediation. In aquifer systems with relatively low buffering capacity the generation of these products can cause significant groundwater acidification thereby inhibiting dehalogenating activity. Where the soil buffering capacity is exceeded, addition of buffer may be needed for the effective continuation of TCE degradation. As an aid to the design of remediation schemes, a geochemical model was designed to predict the amount of buffer required to maintain the source zone pH at a suitable level for dechlorinating bacteria (i.e. > 6.5). The model accounts for the amount of TCE to be degraded, site water chemistry, type of organic amendment and soil mineralogy. It assumes complete dechlorination of TCE, and further considers mineral dissolution and precipitation kinetics. The model is applicable to a wide range of sites. For illustration we present results pertinent to the SABRE field site. Model results indicate that, for the extensive dechlorination expected in proximity to the SABRE DNAPL source zone, significant buffer addition may be necessary. Additional simulations are performed to identify buffer requirements over a wider range of field conditions.

  1. Effects of lactone, ketone, and phenolic compounds on methane production and metabolic intermediates during anaerobic digestion.

    Science.gov (United States)

    Wikandari, Rachma; Sari, Noor Kartika; A'yun, Qurrotul; Millati, Ria; Cahyanto, Muhammad Nur; Niklasson, Claes; Taherzadeh, Mohammad J

    2015-02-01

    Fruit waste is a potential feedstock for biogas production. However, the presence of fruit flavors that have antimicrobial activity is a challenge for biogas production. Lactones, ketones, and phenolic compounds are among the several groups of fruit flavors that are present in many fruits. This work aimed to investigate the effects of two lactones, i.e., γ-hexalactone and γ-decalactone; two ketones, i.e., furaneol and mesifurane; and two phenolic compounds, i.e., quercetin and epicatechin on anaerobic digestion with a focus on methane production, biogas composition, and metabolic intermediates. Anaerobic digestion was performed in a batch glass digester incubated at 55 °C for 30 days. The flavor compounds were added at concentrations of 0.05, 0.5, and 5 g/L. The results show that the addition of γ-decalactone, quercetin, and epicathechin in the range of 0.5-5 g/L reduced the methane production by 50 % (MIC50). Methane content was reduced by 90 % with the addition of 5 g/L of γ-decalactone, quercetin, and epicathechin. Accumulation of acetic acid, together with an increase in carbon dioxide production, was observed. On the contrary, γ-hexalactone, furaneol, and mesifurane increased the methane production by 83-132 % at a concentration of 5 g/L.

  2. The opposing effects of bacterial activity and gas production on anaerobic TCE degradation in soil columns.

    Science.gov (United States)

    Singhal, Naresh; Jaffé, Peter; Maier, Walter; Jho, Eun Hea

    2007-11-01

    This laboratory study explores the effect of growth substrate concentration on the anaerobic degradation of trichloroethylene (TCE) in sand packed columns. In all columns the growth substrate rapidly degraded to gas, that formed a separate phase. Biomass accumulated in the 0-4.8 cm section of the columns in proportion to the influent growth substrate concentration and biomass concentrations in the remaining sections of all columns were similar to the column receiving the lowest substrate concentration. Increases in growth substrate concentration up to 3030 mg-CODl(-1) promoted TCE degradation, but a further increase to 14300 mg-CODl(-1) reduced the amount of TCE completely dechlorinated but did not affect the production of chlorinated TCE intermediates. The mathematical model developed here satisfactorily described the enhancement in TCE dehalogenation for substrate concentration up to 3030 mg-CODl(-1); reproducing TCE dehalogenation for 14300 mg-CODl(-1) required that the moisture content used in simulation be lowered to 0.1. The study shows that volatilization of TCE can be significant and volatilization losses should be taken into account when anaerobic activity in in-situ bioremediation applications is stimulated via addition of growth substrates. An implication of the modeling simulations is that maintaining a lower, but uniform, substrate concentration over the contaminated region may lead to faster contaminant degradation.

  3. Effect of organic loading rate during anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Dhar, Hiya; Kumar, Pradeep; Kumar, Sunil; Mukherjee, Somnath; Vaidya, Atul N

    2016-10-01

    The effect of chemical oxygen demand (COD) and volatile solids (VS) on subsequent methane (CH4) production during anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW) was studied in a laboratory-scale digester. The experiment was performed in 2L anaerobic digester under different experimental conditions using different input mass co-digested with inoculum and organic loading rate (OLR) for 27days at 38±2°C. Three digesters (digesters 1, 2 and 3) were operated at initial loading of 5.1, 10.4 and 15.2g/L CODS per batch which were reduced to 77.9% and 84.2%, respectively. Cumulative biogas productions were 9.3, 10.7 and 17.7L in which CH4 yields were 84.3, 101.0 and 168.4mL/gVS removal in digesters 1, 2, and 3, respectively. The observed COD removal was found to be influenced on variation in CH4 production. Co-efficient of determination (R(2)) was 0.67 and 0.74 in digesters 1 and 2, respectively.

  4. Effect of Microwave and Ultrasonic Pretreatments on Biogas Production from Anaerobic Digestion of Palm Oil Mill Effleunt

    Directory of Open Access Journals (Sweden)

    N. Saifuddin

    2009-01-01

    Full Text Available Problem Statement: Oil palm production is a major agricultural industry in Malaysia. In 2006, palm oil mills in Malaysia produced more than 58 million tonnes of Palm Oil Mill Effluent (POME. Existing treatment in a series of open lagoons at high ambient temperatures, results in the uncontrolled production of methane and carbon dioxide, which are both green house gases (GHGs. With the increased worldwide concern on environmentally friendly production processes particularly the emission of methane, it is important to develop an alternative concept for POME treatment. This study elucidates the effects of pre-treatment of palm oil mill effluent by microwave irradiation and ultrasonic on anaerobic digestion. Approach: Effects of pre-treatment on sludge characterisation parameters were monitored. The Soluble Chemical Oxygen Demand (SCOD/total COD ratio and biodegradability of soluble organic matter increased significantly after both the pre-treatments which indicated an increase in disintegration of the floc structure of the sludge. Three identical bioreactors with working volume of 5 litres were used as anaerobic digesters at 32-35°C. The reactors were separately fed with pre-treated sludge (microwave, ultrasonic and combination of microwave and ultrasonic and control sludge at different Hydraulic Retention Times (HRT to check for the production of methane. Results: The maximum SCOD/TCOD ratio reached almost 29% after 30 min of ultrasonic treatment, while it was 45% after 7 min of microwave irradiation. The BOD5/SCOD ratio also increased after the pre-treatments suggesting the biodegradability of the soluble organic material increased during the treatment. It was observed that TVFA released was increased after both the treatments, with microwave treatment showing a higher yield of TVFA. Greatest enhancement in methane production was shown by the 3 min microwave plus 10 min ultrasonic treatment. Conclusion: The microwave in combination with

  5. The control of H2S in biogas using iron ores as in situ desulfurizers during anaerobic digestion process.

    Science.gov (United States)

    Zhou, Qiying; Jiang, Xia; Li, Xi; Jiang, Wenju

    2016-09-01

    In this study, five kinds of iron ores, limonite, hematite, manganese ore, magnetite and lava rock, were used as the in situ desulfurizers in the anaerobic digestion reactors to investigate their effects on controlling H2S in biogas. The results show that the addition of the five iron ores could significantly control the content of H2S in biogas, with the best performance for limonite. As limonite dosages increase (10-60 g/L), the contents of H2S in biogas were evidently decreased in the digesters with different initial sulfate concentrations (0-1000 mg/L). After the anaerobic digestion, the removed sulfur was mostly deposited on the surface of limonite. A possible mechanism of H2S control in biogas by limonite was proposed preliminarily, including adsorption, FeS precipitation, and Fe (III) oxidation. The results demonstrated that limonite was a promising in situ desulfurizer for controlling H2S in biogas with low cost and high efficiency.

  6. Microbial community structure in a thermophilic aerobic digester used as a sludge pretreatment process for the mesophilic anaerobic digestion and the enhancement of methane production.

    Science.gov (United States)

    Jang, Hyun Min; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

    2013-10-01

    An effective two-stage sewage sludge digestion process, consisting of thermophilic aerobic digestion (TAD) followed by mesophilic anaerobic digestion (MAD), was developed for efficient sludge reduction and methane production. Using TAD as a biological pretreatment, the total volatile suspended solid reduction (VSSR) and methane production rate (MPR) in the MAD reactor were significantly improved. According to denaturing gradient gel electrophoresis (DGGE) analysis, the results indicated that the dominant bacteria species such as Ureibacillus thermophiles and Bacterium thermus in TAD were major routes for enhancing soluble organic matter. TAD pretreatment using a relatively short SRT of 1 day showed highly increased soluble organic products and positively affected an increment of bacteria populations which performed interrelated microbial metabolisms with methanogenic species in the MAD; consequently, a quantitative real-time PCR indicated greatly increased Methanosarcinales (acetate-utilizing methanogens) in the MAD, resulting in enhanced methane production.

  7. Evidence for the cooccurrence of nitrite-dependent anaerobic ammonium and methane oxidation processes in a flooded paddy field.

    Science.gov (United States)

    Shen, Li-Dong; Liu, Shuai; Huang, Qian; Lian, Xu; He, Zhan-Fei; Geng, Sha; Jin, Ren-Cun; He, Yun-Feng; Lou, Li-Ping; Xu, Xiang-Yang; Zheng, Ping; Hu, Bao-Lan

    2014-12-01

    Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two of the most recent discoveries in the microbial nitrogen cycle. In the present study, we provide direct evidence for the cooccurrence of the anammox and n-damo processes in a flooded paddy field in southeastern China. Stable isotope experiments showed that the potential anammox rates ranged from 5.6 to 22.7 nmol N2 g(-1) (dry weight) day(-1) and the potential n-damo rates varied from 0.2 to 2.1 nmol CO2 g(-1) (dry weight) day(-1) in different layers of soil cores. Quantitative PCR showed that the abundance of anammox bacteria ranged from 1.0 × 10(5) to 2.0 × 10(6) copies g(-1) (dry weight) in different layers of soil cores and the abundance of n-damo bacteria varied from 3.8 × 10(5) to 6.1 × 10(6) copies g(-1) (dry weight). Phylogenetic analyses of the recovered 16S rRNA gene sequences showed that anammox bacteria affiliated with "Candidatus Brocadia" and "Candidatus Kuenenia" and n-damo bacteria related to "Candidatus Methylomirabilis oxyfera" were present in the soil cores. It is estimated that a total loss of 50.7 g N m(-2) per year could be linked to the anammox process, which is at intermediate levels for the nitrogen flux ranges of aerobic ammonium oxidation and denitrification reported in wetland soils. In addition, it is estimated that a total of 0.14 g CH4 m(-2) per year could be oxidized via the n-damo process, while this rate is at the lower end of the aerobic methane oxidation rates reported in wetland soils.

  8. Mathematical model of anaerobic digestion in a chemostat: effects of syntrophy and inhibition.

    Science.gov (United States)

    Weedermann, Marion; Seo, Gunog; Wolkowicz, Gail S K

    2013-01-01

    Three of the four main stages of anaerobic digestion: acidogenesis, acetogenesis, and methanogenesis are described by a system of differential equations modelling the interaction of microbial populations in a chemostat. The microbes consume and/or produce simple substrates, alcohols and fatty acids, acetic acid, and hydrogen. Acetogenic bacteria and hydrogenotrophic methanogens interact through syntrophy. The model also includes the inhibition of acetoclastic and hydrogenotrophic methanogens due to sensitivity to varying pH-levels. To examine the effects of these interactions and inhibitions, we first study an inhibition-free model and obtain results for global stability using differential inequalities together with conservation laws. For the model with inhibition, we derive conditions for existence, local stability, and bistability of equilibria and present a global stability result. A case study illustrates the effects of inhibition on the regions of stability. Inhibition introduces regions of bistability and stabilizes some equilibria.

  9. Effect of urea addition on giant reed ensilage and subsequent methane production by anaerobic digestion.

    Science.gov (United States)

    Liu, Shan; Ge, Xumeng; Liew, Lo Niee; Liu, Zhe; Li, Yebo

    2015-09-01

    The effect of urea addition on giant reed ensilage and sequential anaerobic digestion (AD) of the ensiled giant reed was evaluated. The dry matter loss during ensilage (up to 90 days) with or without urea addition was about 1%. Addition of 2% urea enhanced production of lactic acid by about 4 times, and reduced production of propionic acid by 2-8 times. Besides, urea addition reduced degradation of cellulose and hemicellulose, and increased degradation of lignin in giant reed during ensilage. Ensilage with or without urea addition had no significant effects on the enzymatic digestibility of giant reed, but ensilage with urea addition achieved a cumulative methane yield of 173 L/kg VS, which was 18% higher than that of fresh giant reed. The improved methane yield of giant reed could be attributed to the production of organic acids and ethanol during ensilage.

  10. Anaerobic digestion of catering wastes: effect of micronutrients and retention time.

    Science.gov (United States)

    Climenhaga, M A; Banks, C J

    2008-01-01

    Source-separated foodwastes collected from a campus catering facility were processed in bench-scale single-stage anaerobic digesters. The feedstock contained a varied mix of fruits, vegetables, meats and fried foods. A constant organic loading rate (OLR) was maintained with differing hydraulic retention times (HRT). Regular addition of trace elements or prolonged retention time allowed stable digestion at high total volatile fatty acid (TVFA) levels. Reactors on HRT of 25, 50, and 100 days with no micronutrient supplementation exhibited methanogenic failure after approximately 40, 100 and 90 days respectively, while duplicate reactors with micronutrient supplementation maintained stable digestion. An extended HRT of 180 days has so far allowed continued digestion (for reactors with and without micronutrient supplementation) at levels of ammonia nitrogen exceeding 5.7 g l(-1) and volatile fatty acid levels exceeding 15 g l(-1), usually considered inhibitory or toxic.

  11. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella

    2014-02-01

    Full Text Available The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong

  12. Anaerobic Digestion Foaming Causes

    OpenAIRE

    Ganidi, Nafsika

    2008-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...

  13. Performance of biological phosphorus removal and characteristics of microbial community in the oxic-settling-anaerobic process by FISH analysis

    Institute of Scientific and Technical Information of China (English)

    Jian-fang WANG; Qing-liang ZHAO; Wen-biao JIN; Shi-jie YOU; Jin-na ZHANG

    2008-01-01

    Performance of biological phosphorus removal in the oxic-settling-anaerobic (OSA) process was investigated. Cell staining and fluorescent in situ hybridization (FISH) were used to analyze characteristics and microbial community of sludge.Experimental results showed that phosphorus removal efficiency was near 60% and the amount of biological phosphorus accumulation in aerobic sludge of the OSA system was up to 26.9 mg/g. Biological phosphorus removal efficiency was partially inhibited by carbon sources in the continuous OSA system. Contrasted to the OSA system, biological phosphorus removal efficiency was enhanced by 14% and the average total phosphorus (TP) contents of aerobic sludge were increased by 0.36 mg/g when sufficient carbon sources were supplied in batch experiments. Staining methods indicated that about 35% of microorganisms had typical characteristics of phosphorus accumulating organisms (PAOs). FISH analysis demonstrated that PAOMIX-binding bacteria were predominant microbial communities in the OSA system, which accounted for around 28% of total bacteria.

  14. Methane production improvement by modulation of solid phase immersion in dry batch anaerobic digestion process: Dynamic of methanogen populations.

    Science.gov (United States)

    André, L; Ndiaye, M; Pernier, M; Lespinard, O; Pauss, A; Lamy, E; Ribeiro, T

    2016-05-01

    Several 60L dry batch anaerobic digestion (AD) reactors were implemented with or without liquid reserve on cattle manure. The immersed part modulation of cattle manure increased the methane flow of about 13%. The quantitative real time PCR and the optimized DNA extraction were implemented and validated to characterize and quantify the methanogen dynamic in dry batch AD process. Final quantities of methanogens converged toward the same level in several inocula at the end of AD. Methanogen dynamic was shown by dominance of Methanosarcinaceae for acetotrophic methanogens and Methanobacteriales for the hydrogenotrophic methanogens. Overall, methanogens populations were stabilized in liquid phase, except Methanosaetaceae. Solid phase was colonized by Methanomicrobiales and Methanosarcinaceae populations giving a support to biofilm development. The methane increase could be explained by a raise of Methanosarcinaceae population in presence of a total contact between solid and liquid phases. Methanosarcinaceae was a bio-indicator of the methane production.

  15. Mesophilic anaerobic co-digestion of poultry dropping and Carica papaya peels: Modelling and process parameter optimization study.

    Science.gov (United States)

    Dahunsi, S O; Oranusi, S; Owolabi, J B; Efeovbokhan, V E

    2016-09-01

    The study evaluated anaerobic co-digestion of poultry dropping and pawpaw peels and the optimization of important process parameters. The physic-chemical analyses of the substrates were done using standard methods after application of mechanical, thermal and chemical pre-treatments methods. Gas chromatography analysis revealed the gas composition to be within the range of 66-68% methane and 18-23% carbon dioxide. The study equally revealed that combination of the different pre-treatment methods enhanced enormous biogas yield from the digestion. Optimization of the generated biogas data were carried out using the Response Surface Methodology and the Artificial Neural Networks. The coefficient of determination (R(2)) for RSM (0.9181) was lower compare to that of ANN (0.9828). This shows that ANN model gives higher accuracy than RSM model for the current. Further usage of Carica papaya peels for biogas generation is advocated.

  16. Enhancement of bioenergy production from organic wastes by two-stage anaerobic hydrogen and methane production process.

    Science.gov (United States)

    Luo, Gang; Xie, Li; Zhou, Qi; Angelidaki, Irini

    2011-09-01

    The present study investigated a two-stage anaerobic hydrogen and methane process for increasing bioenergy production from organic wastes. A two-stage process with hydraulic retention time (HRT) 3d for hydrogen reactor and 12d for methane reactor, obtained 11% higher energy compared to a single-stage methanogenic process (HRT 15 d) under organic loading rate (OLR) 3 gVS/(L d). The two-stage process was still stable when the OLR was increased to 4.5 gVS/(Ld), while the single-stage process failed. The study further revealed that by changing the HRT(hydrogen):HRT(methane) ratio of the two-stage process from 3:12 to 1:14, 6.7%, more energy could be obtained. Microbial community analysis indicated that the dominant bacterial species were different in the hydrogen reactors (Thermoanaerobacterium thermosaccharolyticum-like species) and methane reactors (Clostridium thermocellum-like species). The changes of substrates and HRT did not change the dominant species. The archaeal community structures in methane reactors were similar both in single- and two- stage reactors, with acetoclastic methanogens Methanosarcina acetivorans-like organisms as the dominant species.

  17. Co-occurrence of nitrite-dependent anaerobic ammonium and methane oxidation processes in subtropical acidic forest soils.

    Science.gov (United States)

    Meng, Han; Wang, Yong-Feng; Chan, Ho-Wang; Wu, Ruo-Nan; Gu, Ji-Dong

    2016-09-01

    Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two new processes of recent discoveries linking the microbial nitrogen and carbon cycles. In this study, 16S ribosomal RNA (rRNA) gene of anammox bacteria and pmoA gene of n-damo bacteria were used to investigate their distribution and diversity in natural acidic and re-vegetated forest soils. The 16S rRNA gene sequences retrieved featured at least three species in two genera known anammox bacteria, namely Candidatus Brocadia anammoxidans, Candidatus Brocadia fulgida, and Candidatus Kuenenia stuttgartiensis while the pmoA gene amplified was affiliated with two species of known n-damo bacteria Candidatus Methylomirabilis oxyfera and a newly established Candidatus Methylomirabilis sp. According to the results, the diversity of anammox bacteria in natural forests was lower than in re-vegetated forests, but no significant difference was observed in n-damo community between them. Quantitative real-time PCR showed that both anammox and n-damo bacteria were more abundant in the lower layer (10-20 cm) than the surface layer (0-5 cm). The abundance of anammox bacteria varied from 2.21 × 10(5) to 3.90 × 10(6) gene copies per gram dry soil, and n-damo bacteria quantities were between 1.69 × 10(5) and 5.07 × 10(6) gene copies per gram dry soil in the two different layers. Both anammox and n-damo bacteria are reported for the first time to co-occur in acidic forest soil in this study, providing a more comprehensive information on more defined microbial processes contributing to C and N cycles in the ecosystems.

  18. Effect of ammoniacal nitrogen on one-stage and two-stage anaerobic digestion of food waste

    Energy Technology Data Exchange (ETDEWEB)

    Ariunbaatar, Javkhlan, E-mail: jaka@unicas.it [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Scotto Di Perta, Ester [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy); Panico, Antonio [Telematic University PEGASO, Piazza Trieste e Trento, 48, 80132 Naples (Italy); Frunzo, Luigi [Department of Mathematics and Applications Renato Caccioppoli, University of Naples Federico II, Via Claudio, 21, 80125 Naples (Italy); Esposito, Giovanni [Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Via Di Biasio 43, 03043 Cassino, FR (Italy); Lens, Piet N.L. [UNESCO-IHE Institute for Water Education, Westvest 7, 2611 AX Delft (Netherlands); Pirozzi, Francesco [Department of Civil, Architectural and Environmental Engineering, University of Naples Federico II, Via Claudio 21, 80125 Naples (Italy)

    2015-04-15

    Highlights: • Almost 100% of the biomethane potential of food waste was recovered during AD in a two-stage CSTR. • Recirculation of the liquid fraction of the digestate provided the necessary buffer in the AD reactors. • A higher OLR (0.9 gVS/L·d) led to higher accumulation of TAN, which caused more toxicity. • A two-stage reactor is more sensitive to elevated concentrations of ammonia. • The IC{sub 50} of TAN for the AD of food waste amounts to 3.8 g/L. - Abstract: This research compares the operation of one-stage and two-stage anaerobic continuously stirred tank reactor (CSTR) systems fed semi-continuously with food waste. The main purpose was to investigate the effects of ammoniacal nitrogen on the anaerobic digestion process. The two-stage system gave more reliable operation compared to one-stage due to: (i) a better pH self-adjusting capacity; (ii) a higher resistance to organic loading shocks; and (iii) a higher conversion rate of organic substrate to biomethane. Also a small amount of biohydrogen was detected from the first stage of the two-stage reactor making this system attractive for biohythane production. As the digestate contains ammoniacal nitrogen, re-circulating it provided the necessary alkalinity in the systems, thus preventing an eventual failure by volatile fatty acids (VFA) accumulation. However, re-circulation also resulted in an ammonium accumulation, yielding a lower biomethane production. Based on the batch experimental results the 50% inhibitory concentration of total ammoniacal nitrogen on the methanogenic activities was calculated as 3.8 g/L, corresponding to 146 mg/L free ammonia for the inoculum used for this research. The two-stage system was affected by the inhibition more than the one-stage system, as it requires less alkalinity and the physically separated methanogens are more sensitive to inhibitory factors, such as ammonium and propionic acid.

  19. Effects of mixture ratio on anaerobic co-digestion with fruit and vegetable waste and food waste of China

    Institute of Scientific and Technical Information of China (English)

    Jia Lin; Jiane Zuo; Lili Gan; Peng Li; Fenglin Liu; Kaijun Wang; Lei Chen; Hainan Gan

    2011-01-01

    The biochemical methane potentials for typical fruit and vegetable waste (FVW) and food waste (FW) from a northern China city were investigated,which were 0.30,0.56 m3 CH4/kgVS (volatile solids) with biodegradabilities of 59.3% and 83.6%,respectively.Individual anaerobic digestion testes of FVW and FW were conducted at the organic loading rate (OLR) of 3 kg VS/(m3·day) using a lab-scale continuous stirred-tank reactor at 35℃.FVW could be digested stably with the biogas production rate of 2.17 m3/(m3.day) and methane production yield of 0.42 m3 CHl4/kg VS.However,anaerobic digestion process for FW was failed due to acids accumulation.The effects of FVW:FW ratio on co-digestion stability and performance were further investigated at the same OLR.At FVW and FW mixing ratios of 2:1 and 1:1,the performance and operation of the digester were maintained stable,with no accumulation of volatile fatty acids (VFA) and ammonia.Changing the feed to a higher FW content in a ratio of FVW to FW 1:2,resulted in an increase in VFAs concentration to 1100-1200 mg/L,and the methanogenesis was slightly inhibited.At the optimum mixture ratio 1:1 for co-digestion of FVW with FW,the methane production yield was 0.49 m3 CHl4/kg VS,and the volatile solids and soluble chemical oxygen demand (sCOD) removal efficiencies were 74.9% and 96.1%,respectively.

  20. Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes.

    Science.gov (United States)

    García-Gen, Santiago; Sousbie, Philippe; Rangaraj, Ganesh; Lema, Juan M; Rodríguez, Jorge; Steyer, Jean-Philippe; Torrijos, Michel

    2015-01-01

    A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 gVS/Ld. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.

  1. Kinetic modelling of anaerobic hydrolysis of solid wastes, including disintegration processes

    Energy Technology Data Exchange (ETDEWEB)

    García-Gen, Santiago [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Sousbie, Philippe; Rangaraj, Ganesh [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Lema, Juan M. [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Rodríguez, Jorge, E-mail: jrodriguez@masdar.ac.ae [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Institute Centre for Water and Environment (iWater), Masdar Institute of Science and Technology, PO Box 54224 Abu Dhabi (United Arab Emirates); Steyer, Jean-Philippe; Torrijos, Michel [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France)

    2015-01-15

    Highlights: • Fractionation of solid wastes into readily and slowly biodegradable fractions. • Kinetic coefficients estimation from mono-digestion batch assays. • Validation of kinetic coefficients with a co-digestion continuous experiment. • Simulation of batch and continuous experiments with an ADM1-based model. - Abstract: A methodology to estimate disintegration and hydrolysis kinetic parameters of solid wastes and validate an ADM1-based anaerobic co-digestion model is presented. Kinetic parameters of the model were calibrated from batch reactor experiments treating individually fruit and vegetable wastes (among other residues) following a new protocol for batch tests. In addition, decoupled disintegration kinetics for readily and slowly biodegradable fractions of solid wastes was considered. Calibrated parameters from batch assays of individual substrates were used to validate the model for a semi-continuous co-digestion operation treating simultaneously 5 fruit and vegetable wastes. The semi-continuous experiment was carried out in a lab-scale CSTR reactor for 15 weeks at organic loading rate ranging between 2.0 and 4.7 g VS/L d. The model (built in Matlab/Simulink) fit to a large extent the experimental results in both batch and semi-continuous mode and served as a powerful tool to simulate the digestion or co-digestion of solid wastes.

  2. Lifecycle Greenhouse Gas Analysis of an Anaerobic Codigestion Facility Processing Dairy Manure and Industrial Food Waste.

    Science.gov (United States)

    Ebner, Jacqueline H; Labatut, Rodrigo A; Rankin, Matthew J; Pronto, Jennifer L; Gooch, Curt A; Williamson, Anahita A; Trabold, Thomas A

    2015-09-15

    Anaerobic codigestion (AcoD) can address food waste disposal and manure management issues while delivering clean, renewable energy. Quantifying greenhouse gas (GHG) emissions due to implementation of AcoD is important to achieve this goal. A lifecycle analysis was performed on the basis of data from an on-farm AcoD in New York, resulting in a 71% reduction in GHG, or net reduction of 37.5 kg CO2e/t influent relative to conventional treatment of manure and food waste. Displacement of grid electricity provided the largest reduction, followed by avoidance of alternative food waste disposal options and reduced impacts associated with storage of digestate vs undigested manure. These reductions offset digester emissions and the net increase in emissions associated with land application in the AcoD case relative to the reference case. Sensitivity analysis showed that using feedstock diverted from high impact disposal pathways, control of digester emissions, and managing digestate storage emissions were opportunities to improve the AcoD GHG benefits. Regional and parametrized emissions factors for the storage emissions and land application phases would reduce uncertainty.

  3. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: enhanced removal of aromatic amines.

    Science.gov (United States)

    Koupaie, E Hosseini; Moghaddam, M R Alavi; Hashemi, S H

    2011-11-15

    The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  4. Effects of extraction procedures on metal binding properties of extracellular polymeric substances (EPS) from anaerobic granular sludges

    NARCIS (Netherlands)

    Abzac, D' P.; Bordas, F.; Hullebusch, E.; Lens, P.N.L.; Guibaud, G.

    2010-01-01

    The effects of the extraction procedure of extracellular polymeric substances (EPS) on their proton/metal binding properties were studied. Nine extraction procedures (one control, four physical and four chemical procedures) were applied to four types of anaerobic granular sludges. The binding capaci

  5. Effect of substrate and cation requirement on anaerobic volatile fatty acid conversion rates at elevated biogas pressure

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Ferrer, I.; Weijma, J.; Lier, van J.B.

    2013-01-01

    This work studied the anaerobic conversion of neutralized volatile fatty acids (VFA) into biogas under Autogenerative High Pressure Digestion (AHPD) conditions. The effects of the operating conditions on the biogas quality, and the substrate utilisation rates were evaluated using 3 AHPD reactors (0.

  6. Effect of vitamin B-12 pulse addition on the performance of cobalt deprived anaerobic granular sludge bioreactors

    NARCIS (Netherlands)

    Fermoso, F.G.; Bartacek, J.; Lens, P.N.L.

    2010-01-01

    The effect of a pulse addition of vitamin B-12 as cobalt source to restore the performance of cobalt depleted methanol-fed bioreactors was investigated. One upflow anaerobic sludge bed (UASB) reactor was supplied with a pulse of vitamin B-12, and its operation was compared to that of another cobalt

  7. Effects of Short Term Camp Periods on Aerobic and Anaerobic Performance Parameters in Ice Hockey National Team Athletes

    Science.gov (United States)

    Eler, Serdar

    2016-01-01

    This study was conducted for determining the effects of trainings, applied to athletes during short term camp period, on their aerobic and anaerobic performance. Measurements were made by the participation of 28 volunteer male ice hockey national team players. During the 15-day camp period, 10-minute running and stretching for warming and then…

  8. Effect of yeast extract on speciation and bioavailability of nickel and cobalt in anaerobic bioreactors

    NARCIS (Netherlands)

    Gonzalez-Gil, G.; Jansen, S.; Zandvoort, M.H.; Leeuwen, van H.P.

    2003-01-01

    The speciation of metals plays an important role in their bioavailability. In the case of anaerobic reactors for the treatment of wastewaters, the ubiquitous presence of sulfide leads to extensive precipitation of metals like nickel and cobalt, which are essential for the metabolism of the anaerobic

  9. Effect of nickel ions on anaerobic methane production from water hyacinth.

    Science.gov (United States)

    Cai, Xuan; Hong, Zi-Jian; Dai, Rui-Hua; Liu, Yan; Liu, Xiang

    2012-01-01

    The effect of different concentrations of nickel ions (Ni(2+), 0, 10, 40 and 80 mg/L) on the anaerobic methane production of water hyacinth were investigated. Under these four concentrations, the methane production in 40 d was 2,275, 2,703, 3,210 and 2,481 mL, respectively. This situation illustrated that the Ni(2+) promoted the growth of hydrogen-producing acetic acid bacteria and methanogenic bacteria, even at high concentrations (i.e. 40-80 mg/L). The highest methane production per unit weight water hyacinth reached 206 mL/gTS with 40 mg/L Ni(2+). Meanwhile, the modified Gompertz and Logistic equations were applied to describe the effect on anaerobic culture of Ni(2+). According to these models, the values of methane production potential (mL) for four concentrations were in the following order: 40 mg/L (3,123.42 ± 60.08) > 10 mg/L (2,541.16 ± 46.94) > 80 mg/L (2,432.36 ± 40.18) > 0 mg/L (2,238.10 ± 31.90). According to the analysis of the digestate, the residual concentration of Ni(2+) was approximately 1.05-4.9 mg/L, which was relatively low compared with the Ni(2+) concentrations in the raw feedstock. The results would provide academic guidance and technical support for treatment of water hyacinth with an accumulation of heavy metals.

  10. Effect of temperature on two-phase anaerobic reactors treating slaughterhouse wastewater

    Directory of Open Access Journals (Sweden)

    Simone Beux

    2007-11-01

    Full Text Available The effectiveness of the anaerobic treatment of effluent from a swine and bovine slaughterhouse was assessed in two sets of two-phase anaerobic digesters, operated with or without temperature control. Set A, consisting of an acidogenic reactor with recirculation and an upflow biological filter as the methanogenic phase, was operated at room temperature, while set B, consisting of an acidogenic reactor without recirculation and an upflow biological filter as the methanogenic phase, was maintained at 32°C. The methanogenic reactors showed COD (Chemical Demand of Oxygen removal above 60% for HRT (Hydraulic Retention Time values of 20, 15, 10, 8, 6, 4, and 2 days. When the HRT value in those reactors was changed to 1 day, the COD percentage removal decreased to 50%. The temperature variations did not have harmful effects on the performance of reactors in set A.Avaliou-se a eficiência do tratamento anaeróbio de efluente de matadouro de suínos e bovinos em dois conjuntos de biodigestores anaeróbios de duas fases, operados com e sem controle de temperatura. O conjunto A, formado por um reator acidogênico com recirculação e um filtro biológico de fluxo ascendente, foi operado a temperatura ambiente e o conjunto B, formado por um reator de fluxo ascendente e um filtro biológico de fluxo ascendente, foi mantido a 32°C. Os reatores metanogênicos apresentaram remoção de DQO acima de 60 % para os TRHs de 20, 15, 10, oito, seis, quatro e dois dias. Quando o TRH destes reatores foi mudado para um dia observou-se uma queda da porcentagem de remoção de DQO para 50 %. As variações de temperatura parecem não ter prejudicado o desempenho dos reatores do conjunto A.

  11. Utilization of biogas produced by anaerobic digestion of agro-industrial waste: Energy, economic and environmental effects.

    Science.gov (United States)

    Hublin, Andrea; Schneider, Daniel Rolph; Džodan, Janko

    2014-07-01

    Anaerobic digestion of agro-industrial waste is of significant interest in order to facilitate a sustainable development of energy supply. Using of material and energy potentials of agro-industrial waste, in the framework of technical, economic, and ecological possibilities, contributes in increasing the share of energy generated from renewable energy sources. The paper deals with the benefits arising from the utilization of biogas produced by co-digestion of whey and cow manure. The advantages of this process are the profitability of the plant and the convenience in realizing an anaerobic digestion plant to produce biogas that is enabled by the benefits from the sale of electric energy at favorable prices. Economic aspects are related to the capital cost (€ 2,250,000) of anaerobic digestion treatment in a biogas plant with a 300 kW power and 510 kW heating unit in a medium size farm (450 livestock units). Considering the optimum biogas yield of 20.7 dm(3) kg(-1) of wet substrate and methane content in the biogas obtained of 79%, the anaerobic process results in a daily methane production of 2,500 kg, with the maximum power generation of 2,160,000 kWh y(-1) and heat generation of 2,400,000 kWh y(-1) The net present value (NPV), internal rate of return (IRR) and payback period for implementation of profitable anaerobic digestion process is evaluated. Ecological aspects related to carbon dioxide (CO2) and methane (CH4) emission reduction are assessed.

  12. A comparative study of the industrial discharges effect on the anaerobic treatment of domestic wastewater in both experimental and pilot-plant scales.

    Science.gov (United States)

    Saddoud, Ahlem; Abdelkafi, Slim; Aloui, Fathi; Sayadi, Sami

    2010-11-01

    The aim of this study was to compare the effect of industrial discharges on the anaerobic treatment of domestic wastewater in both laboratory and pilot-plant scales at mesophilic conditions. The laboratory experiment results have shown the low process efficiency of anaerobic treatment of DW by the use of an adapted or a non-adapted methanogenic inoculum. These experiments performed in batch digesters were further confirmed by scaling up to a pilot-plant anaerobic membrane bioreactor (MBR). The treatment inefficiency in both laboratory and pilot-plant experiments could be related to the presence of toxic compounds due to the wastewater contamination by industrial discharges. The toxic character of DW was proved by the phytotoxicity and microtoxicity tests. Indeed, the luminescence inhibition percentages started at an average of 21% in the morning and reached more than 84% in the late afternoon. Moreover, the toxicity results have shown a direct relation with methanization results. Indeed, when the average microtoxicity increased to 73%, the average germination index value and the methanization efficiency expressed as the average methane percentage in the produced biogas decreased to 0% and 14.5%, respectively.

  13. Slow swimming, fast strikes: effects of feeding behavior on scaling of anaerobic metabolism in epipelagic squid.

    Science.gov (United States)

    Trueblood, Lloyd A; Seibel, Brad A

    2014-08-01

    Many pelagic fishes engage prey at high speeds supported by high metabolic rates and anaerobic metabolic capacity. Epipelagic squids are reported to have among the highest metabolic rates in the oceans as a result of demanding foraging strategies and the use of jet propulsion, which is inherently inefficient. This study examined enzymatic proxies of anaerobic metabolism in two species of pelagic squid, Dosidicus gigas and Doryteuthis pealeii (Lesueur 1821), over a size range of six orders of magnitude. We hypothesized that activity of the anaerobically poised enzymes would be high and increase with size as in ecologically similar fishes. In contrast, we demonstrate that anaerobic metabolic capacity in these organisms scales negatively with body mass. We explored several cephalopod-specific traits, such as the use of tentacles to capture prey, body morphology and reduced relative prey size of adult squids, that may create a diminished reliance on anaerobically fueled burst activity during prey capture in large animals.

  14. Anaerobic digestion of sludge: application of fluorescence microscopy for process analysis; Digestion anaerobia de lodos de depuradora: aplicacion de la microscopia de epifluorescencia al analisis del proceso

    Energy Technology Data Exchange (ETDEWEB)

    Solera, R.; Rubia de la, M. A.; Romero, L.; Sales, D.

    2001-07-01

    In this paper, we studied the industrial-scale mesophilic anaerobic digestion of sludge. We used fluorescence microscopy methods to count the bacterial population involved in this process. The results are compared to those obtained in a previous laboratory-scale study in thermophilic temperature. (Author) 11 refs.

  15. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: Enhanced removal of aromatic amines

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini Koupaie, E., E-mail: ehssan.hosseini.k@gmail.com [Civil and Environmental Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of); Alavi Moghaddam, M.R., E-mail: alavim@yahoo.com [Civil and Environmental Engineering Department, Amirkabir University of Technology (AUT), Hafez Ave., Tehran 15875-4413 (Iran, Islamic Republic of); Hashemi, S.H., E-mail: h_hashemi@sbu.ac.ir [Environmental Science Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

    2011-11-15

    Highlights: {yields} Biofilm process was applied as post-treatment of anaerobically degraded an azo dye. {yields} More than 65% of the dye total metabolites was completely mineralized. {yields} Based on HPLC analysis, more than 80% of 1-naphthylamine-4-sulfonate was removed. {yields} Inhibition of biofilm growth was increased with increasing the initial dye concentration. {yields} Considerable porous morphology was observed in the SEM photographs of the biofilm. - Abstract: The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  16. A case study of coupling upflow anaerobic sludge blanket (UASB) and ANITA™ Mox process to treat high-strength landfill leachate.

    Science.gov (United States)

    Lu, Ting; George, Biju; Zhao, Hong; Liu, Wenjun

    2016-01-01

    A pilot study was conducted to study the treatability of high-strength landfill leachate by a combined process including upflow anaerobic sludge blanket (UASB), carbon removal (C-stage) moving bed biofilm reactor (MBBR) and ANITA™ Mox process. The major innovation on this pilot study is the patent-pending process invented by Veolia that integrates the above three unit processes with an effluent recycle stream, which not only maintains the low hydraulic retention time to enhance the treatment performance but also reduces inhibiting effect from chemicals present in the high-strength leachate. This pilot study has demonstrated that the combined process was capable of treating high-strength leachate with efficient chemical oxygen demand (COD) and nitrogen removals. The COD removal efficiency by the UASB was 93% (from 45,000 to 3,000 mg/L) at a loading rate of 10 kg/(m(3)·d). The C-stage MBBR removed an additional 500 to 1,000 mg/L of COD at a surface removal rate (SRR) of 5 g/(m(2)·d) and precipitated 400 mg/L of calcium. The total inorganic nitrogen removal efficiency by the ANITA Mox reactor was about 70% at SRR of 1.0 g/(m(2)·d).

  17. Anaerobic digestion for sustainable development: a natural approach

    Energy Technology Data Exchange (ETDEWEB)

    Gijzen, H.J.

    2002-07-01

    After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These ''natural reactors'' exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic post-treatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. In conclusion: a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery. (author)

  18. Effect of the presence of the antimicrobial tylosin in swine waste on anaerobic treatment.

    Science.gov (United States)

    Angenent, Largus T; Mau, Margit; George, Usha; Zahn, James A; Raskin, Lutgarde

    2008-05-01

    An anaerobic sequencing batch reactor (ASBR), seeded with a biomass inoculum that previously had not been exposed to the macrolide antimicrobial tylosin (mixture of Tylosin A, B, C, and D), was operated for 3 months with swine waste without Tylosin A and for 9 months with swine waste containing Tylosin A at an average concentration of 1.6 mg/L. When swine waste with tylosin was fed to the ASBR, methane production and volatile solids removal did not appear to be inhibited and a methane yield of 0.47 L methane per gram volatile solids fed to the ASBR was observed. Throughout the operating period, Tylosin A levels in ASBR biomass and effluent were below the detection limit of 0.01 mg/L. However, during the first 3 months of operation, the levels of macrolide-lincosamide-streptogramin B (MLSB)-resistant bacteria in the ASBR biomass increased substantially as determined by hybridizations with oligonucleotide probes designed to target MLSB-resistant bacteria. Since no Tylosin A was present in the swine waste during the initial 3 months, the presence of MLSB-resistant bacteria in the swine waste was likely the reason for the increase in resistance. Subsequently, the levels of MLSB-resistant bacteria in ASBR biomass stabilized with an average of 44.9% for the 9 months of operation with swine waste containing Tylosin A. The level of MLSB-resistant bacteria in the swine waste fed to the ASBR during this period averaged 18.0%. The results indicate that anaerobic treatment of a waste stream containing tylosin was effective (based on reactor performance) and that the level of resistant bacteria in the ASBR was substantially higher than in the waste stream fed to this system.

  19. Effects of acute aerobic and anaerobic exercise on blood markers of oxidative stress.

    Science.gov (United States)

    Bloomer, Richard J; Goldfarb, Allan H; Wideman, Laurie; McKenzie, Michael J; Consitt, Leslie A

    2005-05-01

    The purpose of this study was to compare oxidative modification of blood proteins, lipids, DNA, and glutathione in the 24 hours following aerobic and anaerobic exercise using similar muscle groups. Ten cross-trained men (24.3 +/- 3.8 years, [mean +/- SEM]) performed in random order 30 minutes of continuous cycling at 70% of Vo(2)max and intermittent dumbbell squatting at 70% of 1 repetition maximum (1RM), separated by 1-2 weeks, in a crossover design. Blood samples taken before, and immediately, 1, 6, and 24 hours postexercise were analyzed for plasma protein carbonyls (PC), plasma malondialdehyde (MDA), and whole-blood total (TGSH), oxidized (GSSG), and reduced (GSH) glutathione. Blood samples taken before and 24 hours postexercise were analyzed for serum 8-hydroxy-2'-deoxyguanosine (8-OHdG). PC values were greater at 6 and 24 hours postexercise compared with pre-exercise for squatting, with greater PC values at 24 hours postexercise for squatting compared with cycling (0.634 +/- 0.053 vs. 0.359 +/- 0.018 nM.mg protein(-1)). There was no significant interaction or main effects for MDA or 8-OHdG. GSSG experienced a short-lived increase and GSH a transient decrease immediately following both exercise modes. These data suggest that 30 minutes of aerobic and anaerobic exercise performed by young, cross-trained men (a) can increase certain biomarkers of oxidative stress in blood, (b) differentially affect oxidative stress biomarkers, and (c) result in a different magnitude of oxidation based on the macromolecule studied. Practical applications: While protein and glutathione oxidation was increased following acute exercise as performed in this study, future research may investigate methods of reducing macromolecule oxidation, possibly through the use of antioxidant therapy.

  20. Potentials for food waste minimization and effects on potential biogas production through anaerobic digestion.

    Science.gov (United States)

    Schott, Anna Bernstad Saraiva; Vukicevic, Sanita; Bohn, Irene; Andersson, Tova

    2013-08-01

    Several treatment alternatives for food waste can result in both energy and nutrient recovery, and thereby potential environmental benefits. However, according to the European Union waste management hierarchy, waste prevention should be the prioritized strategy to decrease the environmental burdens from all solid waste management. The aim of the present study was therefore to investigate the potential for food waste minimization among Swedish households through an investigation of the amount of avoidable food waste currently disposed of. A further aim was to investigate the effect on the national biogas production potential through anaerobic digestion of food waste, considering minimization potentials. A method for waste composition analyses of household food waste, where a differentiation between avoidable and unavoidable food waste is made, was used in a total of 24 waste composition analyses of household waste from Swedish residential areas. The total household food waste generation reached 3.4 kg (household and week)(-1), on average, of which 34% is avoidable. The theoretical methane (CH4) potential in unavoidable food waste reached 442 Ndm(3) (kg VS)(-1) or 128 Nm(3) tonne(-1) wet waste, while the measured (mesophilic CH4 batch tests) CH4 production reached 399 Ndm(3) (kg VS)(-1), which is lower than several previous assessments of CH4 production from household food waste. According to this study the combination of a decrease in food waste generation-in case of successful minimization-and decreased CH4 production from unavoidable food waste will thus result in lower total potential energy recovery from household food waste through anaerobic digestion CH4 potential than previously stated.

  1. INCREASING ANAEROBIC DIGESTION PERFORMANCE OF WASTEWATER WITH CO-DIGESTION USING DECANTER CAKE

    OpenAIRE

    Thaniya Kaosol; Narumol Sohgrathok

    2014-01-01

    Low biogas production in the frozen seafood wastewater anaerobic digestion is observed due to the low organic and Total Solids (TS) contents in the wastewater. In this research the decanter cake will be used in the anaerobic co-digestion process to improve the biogas production rate. The effect of co-digestion and Hydraulic Retention Time (HRT) will be investigated using the continuously stirred tank reactors under anaerobic conditions. Moreover, the study determines the biogas production pot...

  2. Effects of phosphate addition on methane fermentation in the batch and upflow anaerobic sludge blanket (UASB) reactors.

    Science.gov (United States)

    Suzuki, Sho; Shintani, Masaki; Sanchez, Zoe Kuizon; Kimura, Kohei; Numata, Mitsuru; Yamazoe, Atsushi; Kimbara, Kazuhide

    2015-12-01

    Ammonia inhibition of methane fermentation is one of the leading causes of failure of anaerobic digestion reactors. In a batch anaerobic digestion reactor with 429 mM NH3-N/L of ammonia, the addition of 25 mM phosphate resulted in an increase in methane production rate. Similar results were obtained with the addition of disodium phosphate in continuous anaerobic digestion using an upflow anaerobic sludge blanket (UASB) reactor. While methane content and production rate decreased in the presence of more than 143 mM NH3-N/L of ammonium chloride in UASB, the addition of 5 mM disodium phosphate suppressed ammonia inhibition at 214 mM NH3-N/L of ammonium chloride. The addition prevented acetate/propionate accumulation, which might be one of the effects of the phosphate on the ammonia inhibition. The effects on the microbial community in the UASB reactor was also assessed, which was composed of Bacteria involved in hydrolysis, acidogenesis, acetogenesis, and dehydrogenation, as well as Archaea carrying out methanogenesis. The change in the microbial community was observed by ammonia inhibition and the addition of phosphate. The change indicates that the suppression of ammonia inhibition by disodium phosphate addition could stimulate the activity of methanogens, reduce shift in bacterial community, and enhance hydrogen-producing bacteria. The addition of phosphate will be an important treatment for future studies of methane fermentation.

  3. Effects of Metal Nanoparticles on Methane Production from Waste-Activated Sludge and Microorganism Community Shift in Anaerobic Granular Sludge

    Science.gov (United States)

    Wang, Tao; Zhang, Dong; Dai, Lingling; Chen, Yinguang; Dai, Xiaohu

    2016-05-01

    Extensive use of nanoparticles (NPs) in consumer and industrial products has led to concerns about their potential environmental impacts; however, the influences of different NPs (e.g., nZVI (nano zero-valent iron), Ag NPs, Fe2O3 NPs and MgO NPs) on the anaerobic digestion of sludge have not yet been studied in depth. Additionally, a new guideline or the use of different NPs in the anaerobic digestion of sludge should be established to improve the anaerobic digestion of sludge and avoid inhibitory effects. This study investigated the effects of four representative NPs (i.e., nZVI, Ag NPs, Fe2O3 NPs and MgO NPs) on methane production during the anaerobic digestion of waste activated sludge (WAS). The presence of 10 mg/g total suspended solids (TSS) nZVI and 100 mg/g TSS Fe2O3 NPs increased methane production to 120% and 117% of the control, respectively, whereas 500 mg/g TSS Ag NPs and 500 mg/g TSS MgO NPs generated lower levels of methane production (73.52% and 1.08% that of the control, respectively). These results showed that low concentrations of nZVI and Fe2O3 NPs promoted the amount of microbes (Bacteria and Archaea) and activities of key enzymes but that higher concentrations of Ag NPs and MgO NPs inhibited them.

  4. High rate CNP removal from a milk processing wastewater in a single ultrasound augmented up-flow anaerobic/aerobic/anoxic bioreactor.

    Science.gov (United States)

    Rezaee, S; Zinatizadeh, A A L; Asadi, A

    2015-03-01

    Simultaneous removal of carbon, nitrogen and phosphorus (CNP) in a single bioreactor is of high significance in terms of reactor volume and energy consumption. Therefore, in this study, an innovative up-flow anaerobic/aerobic/anoxic bioreactor (UAAASB) augmented by ultrasound was developed as a high rate single bioreactor for the simultaneous removal of nutrients from a milk processing wastewater. The ultrasonic irradiation used in this work was in the range of high frequency (1.7 MHz). The central composite design (CCD) and response surface methodology (RSM) were applied to design the experimental conditions, model obtained data, and optimize the process. The effects of three independent variables, i.e. hydraulic retention time (HRT), aeration mode and mixed liquor suspended solid (MLSS) concentration on 10 process responses were investigated. The results prove that the ultrasonic irradiation has a positive effect on the sludge settling velocity and effluent turbidity. The optimum conditions were determined as 12-15 h, 4000-5000 mg/l and 1.5-2 for HRT, MLSS concentration and aeration mode, respectively, based on removal efficiency of sCOD ⩾ 90%, TN and TP ⩾ 50%.

  5. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Li, Yu-You, E-mail: yyli@epl1.civil.tohoku.ac.jp [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi’an University of Architecture and Technology, Xi’an (China)

    2015-09-15

    Highlights: • Microbial community dynamics and process functional resilience were investigated. • The threshold of TAN in mesophilic reactor was higher than the thermophilic reactor. • The recoverable archaeal community dynamic sustained the process resilience. • Methanosarcina was more sensitive than Methanoculleus on ammonia inhibition. • TAN and FA effects the dynamic of hydrolytic and acidogenic bacteria obviously. - Abstract: While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000 mg/L with free ammonia (FA) 2000 mg/L compared to 16,000 mg/L (FA1500 mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gV S{sub in} in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages.

  6. Anaerobic effluent disinfection using ozone: Byproducts formation

    NARCIS (Netherlands)

    Silva, G.H.R.; Daniel, L.A.; Bruning, H.; Rulkens, W.H.

    2010-01-01

    This research was aimed at studying oxidation processes, coliform inactivation effectiveness and disinfection byproducts (DBPs) associated with the disinfection of anaerobic sanitary wastewater effluent with ozone applied at doses of 5.0, 8.0 and 10.0mg O(3)L(-1) for contact times of 5, 10 and 15 mi

  7. [Anaerobic digestion of lignocellulosic biomass with animal digestion mechanisms].

    Science.gov (United States)

    Wu, Hao; Zhang, Pan-Yue; Guo, Jian-Bin; Wu, Yong-Jie

    2013-02-01

    Lignocellulosic material is the most abundant renewable resource in the earth. Herbivores and wood-eating insects are highly effective in the digestion of plant cellulose, while anaerobic digestion process simulating animal alimentary tract still remains inefficient. The digestion mechanisms of herbivores and wood-eating insects and the development of anaerobic digestion processes of lignocellulose were reviewed for better understanding of animal digestion mechanisms and their application in design and operation of the anaerobic digestion reactor. Highly effective digestion of lignocellulosic materials in animal digestive system results from the synergistic effect of various digestive enzymes and a series of physical and biochemical reactions. Microbial fermentation system is strongly supported by powerful pretreatment, such as rumination of ruminants, cellulase catalysis and alkali treatment in digestive tract of wood-eating insects. Oxygen concentration gradient along the digestive tract may stimulate the hydrolytic activity of some microorganisms. In addition, the excellent arrangement of solid retention time, digesta flow and end product discharge enhance the animal digestion of wood cellulose. Although anaerobic digestion processes inoculated with rumen microorganisms based rumen digestion mechanisms were developed to treat lignocellulose, the fermentation was more greatly limited by the environmental conditions in the anaerobic digestion reactors than that in rumen or hindgut. Therefore, the anaerobic digestion processes simulating animal digestion mechanisms can effectively enhance the degradation of wood cellulose and other organic solid wastes.

  8. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  9. Methane production from rice straw with acclimated anaerobic sludge: effect of phosphate supplementation.

    Science.gov (United States)

    Lei, Zhongfang; Chen, Jiayi; Zhang, Zhenya; Sugiura, Norio

    2010-06-01

    Rice straw particles were directly used as substrate for anaerobic digestion with acclimated sludge under room temperature and different levels of phosphate. Two obvious biogas production peaks were observed for all reactors, with biogas or methane yields of (0.33-0.35)m(3)/kg-VS loaded or (0.27-0.29)m(3) CH(4)/kg-VS loaded and average methane contents of 75.9-78.2%. A separated two-stage first-order kinetic model was developed in this study and showed a good fit to the experimental data when this complicated process was divided into two stages. The average biogas and methane production rate constants were (0.027-0.031)d(-1) and (0.028-0.033)d(-1), respectively, increased by 2-3 times in the second stages than those in the first. The results indicated that an adequate level of phosphate addition (465 mg-P/L) could accelerate the biogasification process: 7-13 days earlier appearance of the two peaks and shorter time needed for complete biogasification of rice straw.

  10. Inhibitory effect of high NH{sub 4}{sup +}–N concentration on anaerobic biotreatment of fresh leachate from a municipal solid waste incineration plant

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhao; Dang, Yan; Li, Caihua; Sun, Dezhi, E-mail: sdzlab@126.com

    2015-09-15

    Highlights: • High NH{sub 4}{sup +}–N concentrations inhibit anaerobic treatment of leachate. • Inhibitory effect of NH{sub 4}{sup +}–N concentrations on anaerobic granular sludge is reversible. • High NH{sub 4}{sup +}–N concentrations inhibit bioactivities of microorganisms instead of survival. - Abstract: Fresh leachate from municipal solid waste (MSW) incineration plants generally contains extremely high NH{sub 4}{sup +}–N concentration which could inhibit the bioactivity of microorganisms. The inhibitory effect of high NH{sub 4}{sup +}–N concentration on anaerobic biotreatment of fresh leachate from a MSW incineration plant in China has been investigated in this study. The inhibition processes was studied by both static tests and a laboratory-scale expanded granular sludge bed (EGSB) reactor. The specific methanogenic activity (SMA) of the microorganisms in anaerobic granular sludge was inhibited with the NH{sub 4}{sup +}–N concentration increasing to 1000 mg/L in static tests. As well the chemical oxygen demand (COD) removal efficiency and the methane yield decreased in the EGSB reactor, while the volatile fatty acids (VFAs) accumulated and extracellular polymeric substances (EPS) of the anaerobic granular sludge increased with NH{sub 4}{sup +}–N concentration rising to 1000 mg/L, without any rebounding during 30 days of operation. Decreasing NH{sub 4}{sup +}–N concentration to 500 mg/L in influent, the COD removal efficiency recovered to about 85% after 26 days. 1000 mg/L of NH{sub 4}{sup +}–N in leachate was suggested to be the inhibition threshold in EGSB reactor. High-throughput sequencing results showed little changes in microbial communities of the sludge for a high NH{sub 4}{sup +}–N concentration, indicating that the survival of most microorganisms was not affected under such a condition. It inhibited the bioactivity of the microorganisms, resulting in decrease of the COD removal efficiency.

  11. Effects of cycle-frequency and temperature on the performance of anaerobic sequencing batch reactors (ASBRs) treating swine waste.

    Science.gov (United States)

    Ndegwa, P M; Hamilton, D W; Lalman, J A; Cumba, H J

    2008-04-01

    Anaerobic digestion of animal waste is a technically viable process for the abatement of adverse environmental impacts caused by animal wastes; however, widespread acceptance has been plagued by poor economics. This situation is dismal if the technology is adapted for treating low strength animal slurries because of large digester-volume requirements and a corresponding high energy input. A possible technology to address these constraints is the anaerobic sequencing batch reactor (ASBR). The ASBR technology has demonstrated remarkable potential to improve the economics of treating dilute animal waste effluents. This paper presents preliminary data on the effects of temperature and frequency-cycle on the operation of an ASBR at a fixed hydraulic retention time (HRT). The results suggest that within the parameter range under consideration, temperature did not affect the biogas yield significantly, however, higher cycle-frequency had a negative effect. The biogas quality (%CH(4)) was not significantly affected by temperature nor by the cycle-frequency. The operating principle of the ASBR follows four phases: feed, react, settle, and decant in a cyclic mode. To improve the biogas production in an ASBR, one long react-phase was preferable compared to three shorter react-phases. Treatment of dilute manure slurries in an ASBR at 20 degrees C was more effective than at 35 degrees C; similarly more bio-stable effluents were obtained at low cycle-frequency. The treatment of dilute swine slurries in an ASBR at the lower temperature (20 degrees C) and lower cycle-frequency is, therefore, recommended for the bio-stabilization of dilute swine wastewaters. The results also indicate that significantly higher VFA degradation occurred at 20 degrees C than at 35 degrees C, suggesting that the treatment of dilute swine slurries in ASBRs for odor control might be more favorable at the lower than at the higher temperatures examined in this study. Volatile fatty acid reduction at the two

  12. Effects of Recovery Type after a Kickboxing Match on Blood Lactate and Performance in Anaerobic Tests

    OpenAIRE

    Ouergui, Ibrahim; Hammouda, Omar; Chtourou, Hamdi; Gmada, Nabil; Franchini, Emerson

    2014-01-01

    Purpose To verify whether active recovery (AR) applied after a kickboxing match resulted in better performance in anaerobic tests when compared to passive recovery (PR). Methods Eighteen kickboxers volunteered to participate on a Kickboxing match preceded and followed by anaerobic tests: squat jump (SJ), the counter movement jump (CMJ) and the upper-body Wingate test. Blood lactate (BL), heart rate (HR) and rate of perceived exertion (RPE) were analyzed before and after rounds. The recovery s...

  13. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  14. [Studies on Effect of Alkali Pretreatment on Anaerobic Digestion of Rice Straw with Confocal Raman Microscopy].

    Science.gov (United States)

    Xia, Yi-hua; Luo, Liu-bin; Li, Xiao-li; He, Yong; Sheng, Kui-chuan

    2015-03-01

    NaOH pretreatment is a convenient and effective method which is widely used in rice straw anaerobic digestion. But the mechanism of the alkaline (NaOH) hydrolysis of biopolymers compositions and polymeric cross-linked network structures of rice straw cell wall need further study. This paper firstly studied the effect and mechanism of alkali pretreatment on anaerobic digestion and biogas production of rice straw by using a combination of confocal Raman microscopy and transmission electron microscope. First, the original rice straw and the rice straw pretreated by NaOH were taken for mapping scanning by confocal Raman microscopy with micron-scale spatial resolution. Then principal component analysis was adopted to extract main information of Raman spectra, it could be found that the two types of samples were respectively presented with ray-like distribution in the first two principal component space, which were with cumulative contribution of 99%. And there was a clear boundary between the two types of samples without any overlapping, indicating that there was a significant difference of Raman spectral characteristic between original rice leaf and rice leaf pretreated by NaOH. Further analysis of the loading weights of the first two principal components showed that the Raman peaks at 1 739, 1 508 and 1 094 cm(-1) were the important bands, and these three Raman peaks were attributed to the scattering of hemicellulose, cellulose and lignin respectively. Following, chemical imaging analysis of hemicellulose, cellulose and lignin were achieved by combining these Raman peaks and microscopic image information. It could be found that the NaOH pretreatment resulted in a loss of dense spatial uniformity structure of tissue and great decreases of the contents of these three ingredients, particularly lignin. It can be concluded that it is feasible to non-destructively measure hemicellulose, lignin and cellulose in rice straw tissue by confocal Raman microscopy, and to achieve

  15. Hydrogen Production By Anaerobic Fermentation Using Agricultural and Food Processing Wastes Utilizing a Two-Stage Digestion System

    OpenAIRE

    Thompson, Reese S

    2008-01-01

    Hydrogen production by means of anaerobic fermentation was researched utilizing three different substrates. Synthetic wastewater, dairy manure, and cheese whey were combined together at different concentrations under batch anaerobic conditions to determine the optimal hydrogen producing potential and waste treatment of each. Cheese whey at a concentration of 55% was combined with dairy manure at a concentration of 45% to produce 1.53 liters of hydrogen per liter of substrate. These results...

  16. Anaerobic Digestion of Piggery Waste

    NARCIS (Netherlands)

    Velsen, van A.F.M.

    1981-01-01

    Anaerobic digestion is a biological process by which organic matter is converted to methane and carbon dioxide by microbes in the absence of air (oxygen). In nature, anaerobic conversions occur at all places where organic material accumulates and the supply of oxygen is deficient, e.g. in marshes an

  17. Optimisation of sewage sludge anaerobic digestion through co-digestion with OFMSW: Effect of collection system and particle size

    Energy Technology Data Exchange (ETDEWEB)

    Silvestre, Gracia [IRTA, GIRO Joint Research Unit IRTA-UPC, Torre Marimon, Barcelona (Spain); Ainia, Departamento de Medio Ambiente, Bioenergía e Higiene Industrial, Paterna, Valencia (Spain); Bonmatí, August [IRTA, GIRO Joint Research Unit IRTA-UPC, Torre Marimon, Barcelona (Spain); Fernández, Belén, E-mail: belen.fernandez@irta.cat [IRTA, GIRO Joint Research Unit IRTA-UPC, Torre Marimon, Barcelona (Spain)

    2015-09-15

    Highlights: • Methane production rate increased between 56% and 208% during OFMSW–SS codigestion. • The OFMSW particle size reduction from 20 to 8 mm did not affect the methane yield. • OFMSW–SS codigestion promoted β-oxidation and acetoclastic methanogenic activity. • The evolution of specific activity was a feasible tool to control the process. - Abstract: The effect of organic fraction of municipal solid waste (OFMSW) loading rate and particulate size on the sewage sludge (SS) mesophilic anaerobic co-digestion was assessed in continuous stirred tank reactor at hydraulic retention time of 20 days. The SS–OFMSW mixture composed by 54% of the volatile solids fed (inlet-VS), at OLR of 3.1 kg{sub COD} m{sup −3} d{sup −1} (1.9 kg{sub VS} m{sup −3} d{sup −1}), showed the highest increment on the volumetric methane production and yield of +200% and +59% respectively, under stable conditions. The effect of particulate size was assessed with the same mixture and same operational conditions but reducing the OFMSW particulate size from 20 mm to 8 mm with the aim to improve the hydrolysis step, but the results showed any influence in the OFMSW particulate size range analysed. In addition, specific biomass activity was assessed at the end of each co-digestion period. Results showed that OFMSW promoted β-oxidation syntrophic acetogens and the acetoclastic methanogens activity; although the last increase of the OFMSW percentage (from 47% to 54% inlet-VS) affected negatively the specific substrate activity, but not inhibitory effect was observed. Therefore, the results obtained in the continuous experiment could be related with some inhibitory or toxic effect and not due to hydrolysis limitation. The specific biomass activity test was demonstrated to be an interesting tool to evaluate and control the co-digestion process, especially when conventional parameters did not explain the behaviour of the biological system.

  18. Inhibitory effects of butyrate on biological hydrogen production with mixed anaerobic cultures.

    Science.gov (United States)

    Zheng, Xian-Jun; Yu, Han-Qing

    2005-01-01

    In this study batch experiments were conducted to investigate the inhibitory effects of butyrate addition on hydrogen production from glucose by using anaerobic mixed cultures. Experimental results showed that addition of butyrate at 4.18 and 6.27 g/l only slightly inhibited hydrogen production, and addition of butyrate at 8.36-12.54 g/l imposed a moderate inhibitory effect on hydrogen production. At addition of 25.08 g/l, butyrate had a strong inhibitory influence on substrate degradation and hydrogen production. The distribution of the volatile fatty acids produced from the acidogeneisis of glucose was significantly influenced by the addition of butyrate. The inhibition of butyrate addition on hydrogen production was described well by a non-competitive and non-linear inhibition model, with the maximum hydrogen production rate of 59.3 ml/g-SS/h, critical added butyrate concentration of 25.08 g/l, and inhibition degree of 0.323, respectively. The C(I,50) values (the butyrate concentration at which bioactivity is reduced by 50%) for hydrogen production rate and yield were estimated as 19.39 and 20.78 g/l of added butyrate, respectively.

  19. Effects of adrenaline on glycogenolysis in resting anaerobic frog muscles studied by 31P-NMR.

    Science.gov (United States)

    Kikuchi, Kimio; Yamada, Takenori; Sugi, Haruo

    2009-11-01

    The effects of adrenaline (also called epinephrine) on glycogenolysis in living anaerobic muscles were examined based on time-dependent changes of (31)P-NMR spectra of resting frog skeletal muscles with and without iodoacetate treatments. The phosphate-metabolite concentration and the intracellular pH determined from the NMR spectra changed with time, reflecting the advancement of various phosphate metabolic reactions coupled with residual ATPase reactions to keep the ATP concentration constant. The results could be explained semi-qualitatively as the ATP regenerative reactions, creatine kinase reaction and glycogenolysis, advanced with time showing the characteristic two phases. Thus, it was clarified for living muscles that adrenaline activates the phosphorylase step of glycogenolysis, and the adrenaline-activated glycogenolysis is further regulated at the phosphofructokinase step by PCr and also possibly by AMP. Associated with the adrenaline-activated glycogenolysis in the examined muscles, the P(i) concentration and the intracellular pH, factors affecting the muscle force, changed significantly, suggesting complicated effects of adrenaline on the muscle contractility.

  20. Effect of moisture on pretreatment efficiency for anaerobic digestion of lignocellulosic substrates.

    Science.gov (United States)

    Peces, M; Astals, S; Mata-Alvarez, J

    2015-12-01

    The present study evaluates the effect of moisture in low-temperature and ultrasound pretreatment on lignocellulosic substrates anaerobic biodegradability, where brewer's spent grain was used as model substrate. Besides moisture content, low-temperature pretreatment was also evaluated in terms of temperature (60-80°C) and exposure time (12-72 h). Likewise, ultrasonication was also evaluated in terms of specific energy (1000-50,000 kJ kg TS(-1)). In addition, the effect of substrate particle size reduction by milling pretreatment was also considered. The results clearly demonstrated that substrate moisture (total solid concentration) is a significant parameter for pretreatment performance, although it has been rarely considered in pretreatment optimisation. Specifically, moisture optimisation increased the methane yield of brewer's spent grain by 6% for low-temperature pretreatment (60°C), and by 14% for ultrasound pretreatment (1000 kJ kg TS(-1)) towards the control (without pretreatment). In both pretreatments, the experimental optimum total solid concentration was 100 gTS kg(-1). Thus, lowering substrate moisture, a strategy suggested attaining energetic pretreatment feasibility, needs to be analysed as another pretreatment variable since it might have limited correlation. Finally, a preliminary energetic balance of the pretreatments under study showed that the extra methane production could not cover the energetic pretreatment expenses.

  1. Effects of Anaerobically Digested Slurry on Meloidogyne incognita and Pratylenchus penetrans in Tomato and Radish Production

    Directory of Open Access Journals (Sweden)

    Yu Yu Min

    2011-01-01

    Full Text Available Since effective disposable way of anaerobically digested biogas slurry is expected, ADS was applied to soil to evaluate its effects on nematode damage. Damage index of tomato by root-knot nematode was significantly (<.05 lower and the growth better in pots applied with ADS (100 and 200 mg NH+4-N kg−1 than that in those with chemical fertilizer and control (no ADS. ADS was applied into radish cultivated fields infested with the root-lesion nematode: a single (100 kg NH+4-N ha−1 in 2007 and 2008 and multiple applications (25, 50, 25 kg NH+4-N ha−1 soil in 2009. Damage to radish was 30% and 50% lower in ADS-treated fields than that in the control in 2007 and 2009, respectively, although not in 2008. These results suggest that application of ADS to fields might be feasible for mitigating nematode damage, but the rate and timing should be considered further for the best application way.

  2. The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity

    Directory of Open Access Journals (Sweden)

    Carl Foster, Courtney V. Farland, Flavia Guidotti, Michelle Harbin, Brianna Roberts, Jeff Schuette, Andrew Tuuri, Scott T. Doberstein, John P. Porcari

    2015-12-01

    Full Text Available High intensity interval training (HIIT has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement. This study compared the effects of two HIIT protocols vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training. Fifty-five untrained college-aged subjects were randomly assigned to three training groups (3x weekly. Steady-state (n = 19 exercised (cycle ergometer 20 minutes at 90% of ventilatory threshold (VT. Tabata (n = 21 completed eight intervals of 20s at 170% VO2max/10s rest. Meyer (n = 15 completed 13 sets of 30s (20 min @ 100% PVO2 max/ 60s recovery, average PO = 90% VT. Each subject did 24 training sessions during 8 weeks. Results: There were significant (p < 0.05 increases in VO2max (+19, +18 and +18% and PPO (+17, +24 and +14% for each training group, as well as significant increases in peak (+8, + 9 and +5% & mean (+4, +7 and +6% power during Wingate testing, but no significant differences between groups. Measures of the enjoyment of the training program indicated that the Tabata protocol was significantly less enjoyable (p < 0.05 than the steady state and Meyer protocols, and that the enjoyment of all protocols declined (p < 0.05 across the duration of the study. The results suggest that although HIIT protocols are time efficient, they are not superior to conventional exercise training in sedentary young adults.

  3. The Effects of High Intensity Interval Training vs Steady State Training on Aerobic and Anaerobic Capacity

    Science.gov (United States)

    Foster, Carl; Farland, Courtney V.; Guidotti, Flavia; Harbin, Michelle; Roberts, Brianna; Schuette, Jeff; Tuuri, Andrew; Doberstein, Scott T.; Porcari, John P.

    2015-01-01

    High intensity interval training (HIIT) has become an increasingly popular form of exercise due to its potentially large effects on exercise capacity and small time requirement. This study compared the effects of two HIIT protocols vs steady-state training on aerobic and anaerobic capacity following 8-weeks of training. Fifty-five untrained college-aged subjects were randomly assigned to three training groups (3x weekly). Steady-state (n = 19) exercised (cycle ergometer) 20 minutes at 90% of ventilatory threshold (VT). Tabata (n = 21) completed eight intervals of 20s at 170% VO2max/10s rest. Meyer (n = 15) completed 13 sets of 30s (20 min) @ 100% PVO2 max/ 60s recovery, average PO = 90% VT. Each subject did 24 training sessions during 8 weeks. Results: There were significant (p HIIT protocols are time efficient, they are not superior to conventional exercise training in sedentary young adults. Key points Steady state training equivalent to HIIT in untrained students Mild interval training presents very similar physiologic challenge compared to steady state training HIIT (particularly very high intensity variants were less enjoyable than steady state or mild interval training Enjoyment of training decreases across the course of an 8 week experimental training program PMID:26664271

  4. [Effect of temperature on H+-K+ exchange in Escherichia coli bacteria during their anaerobic growth].

    Science.gov (United States)

    Vardanian, V; Trchunian, A

    1998-01-01

    The H(+)-K(+)-exchange in E.coli grown under anaerobic conditions at temperatures from 17 to 37 degrees C was studied. The Arrhenius plots for both the N,N'-dicyclohexylcarbodiimide-sensitive release of H+ and K+ uptake by cells transferred into a fresh medium containing a carbon source (glucose) are nonlinear. The activation energy values for the transport of these cations at different temperatures significantly differ. It is shown that as the temperature decreases, the accumulation of K+ by cells is reduced. In this process, the initial rate of K+ absorption through the TrkA system, the time of accumulation of these cations by cells and the osmosensitivity of K+ uptake substantially decrease. At temperatures below 20 degrees C, the absorption becomes insensitive to the secondary osmoshock. However, the stoichiometry of N,N'-dicyclohexylcar-bodiimide-sensitive cation fluxes remains unchanged and is equal to 2H+:K+. It is assumed that the H(+)-K(+)-exchange proceeds by the operation of an ensemble of oligomers, formed from the protomers of F0F1 and TrkA, which rearrange by the action of temperature, whereas F0F1 and TrkA in each protomer do not change.

  5. Pilot-scale anaerobic co-digestion of municipal biomass waste and waste activated sludge in China: Effect of organic loading rate

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiao, E-mail: liuxiao07@mails.tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China); Wang Wei; Shi Yunchun; Zheng Lei [School of Environment, Tsinghua University, Beijing 100084 (China); Gao Xingbao [Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Qiao Wei [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249 (China); Zhou Yingjun [Department of Urban and Environmental Engineering, Graduate School of Engineering, Kyoto University, Katsura, Nisikyo-ku, Kyoto 615-8540 (Japan)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) was examined on a pilot-scale reactor. Black-Right-Pointing-Pointer System performance and stability under OLR of 1.2, 2.4, 3.6, 4.8, 6.0 and 8.0 kg VS (m{sup 3} d){sup -1} were analyzed. Black-Right-Pointing-Pointer A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and HRT of 15d. Black-Right-Pointing-Pointer With the increasing OLRs, pH values, VS removal rate and methane concentration decreased and VFA increased. Black-Right-Pointing-Pointer The changing of biogas production rate can be a practical approach to monitor and control anaerobic digestion system. - Abstract: The effects of organic loading rate on the performance and stability of anaerobic co-digestion of municipal biomass waste (MBW) and waste activated sludge (WAS) were investigated on a pilot-scale reactor. The results showed that stable operation was achieved with organic loading rates (OLR) of 1.2-8.0 kg volatile solid (VS) (m{sup 3} d){sup -1}, with VS reduction rates of 61.7-69.9%, and volumetric biogas production of 0.89-5.28 m{sup 3} (m{sup 3} d){sup -1}. A maximum methane production rate of 2.94 m{sup 3} (m{sup 3} d){sup -1} was achieved at OLR of 8.0 kg VS (m{sup 3} d){sup -1} and hydraulic retention time of 15 days. With increasing OLRs, the anaerobic reactor showed a decrease in VS removal rate, average pH value and methane concentration, and a increase of volatile fatty acid concentration. By monitoring the biogas production rate (BPR), the anaerobic digestion system has a higher acidification risk under an OLR of 8.0 kg VS (m{sup 3} d){sup -1}. This result remarks the possibility of relating bioreactor performance with BPR in order to better understand and monitor anaerobic digestion process.

  6. Rapid start-up of anaerobic ammonium oxidation (anammox) process for nitrogen removal from wastewater

    OpenAIRE

    Ali, Muhammad

    2015-01-01

    The dissertation is associated with the field of biological wastewater treatment and more precisely focus on nitrogen removal from wastewater. The nutrients removal (mainly N and P) from wastewater is necessary in order to avoid the eutrophication of the surface waters. Nitrogen compounds (NH4+, NO2- and NO3-) removal is commonly performed by means of biological processes due to the lower cost as compared to chemical treatment. The conventional nitrogen removal process consists of two steps, ...

  7. Effect of ferrous chloride on biogas production and enzymatic activities during anaerobic fermentation of cow dung and Phragmites straw.

    Science.gov (United States)

    Zhang, Huayong; Tian, Yonglan; Wang, Lijun; Mi, Xueyue; Chai, Yang

    2016-06-01

    The effect of ferrous (added as FeCl2) on the anaerobic co-digestion of Phragmites straw and cow dung was studied by investigating the biogas properties, pH values, organic matter degradation (COD) and enzyme activities (cellulase, protease and dehydrogenase) at different stages of mesophilic fermentation. The results showed that Fe(2+) addition increased the cumulative biogas yields by 18.1 % by extending the peak period with high daily biogas yields. Meanwhile, the methane (CH4) contents in the Fe(2+) added groups were generally higher than the control group before the 15th day. The pH values were not significantly impacted by Fe(2+) concentrations during the fermentation process. The COD concentrations, cellulase, protease and dehydrogenase activities varied with the added Fe(2+) concentrations and the stages of the fermentation process. At the beginning stage of fermentation (4th day), Fe(2+) addition increased the biogas production by improving the cellulase and dehydrogenase activities which caused a decline in COD. At the peak stage of fermentation (8th day), Fe(2+) addition enhanced the cellulase and protease activities, and resulted in lower COD contents than the control group. When the biogas yields decreased again (13th day), the COD contents varied similar with the protease and dehydrogenase activities, whilst cellulase activities were not sensitive to Fe(2+) concentrations. At the end of fermentation (26th day), Fe(2+) addition decreased the cellulase activities, led to lower COD contents and finally resulted the lower biogas yields than the control group. Taking the whole fermentation process into account, the promoting effect of Fe(2+) addition on biogas yields was mainly attributed to the extension of the gas production peak stage and the improvement of cellulase activities.

  8. Bio-hydrolysis and bio-hydrogen production from food waste by thermophilic and hyperthermophilic anaerobic process.

    Science.gov (United States)

    Algapani, Dalal E; Qiao, Wei; Su, Min; di Pumpo, Francesca; Wandera, Simon M; Adani, Fabrizio; Dong, Renjie

    2016-09-01

    High-temperature pretreatment plays a key role in the anaerobic digestion of food waste (FW). However, the suitable temperature is not yet determined. In this work, a long-term experiment was conducted to compare hydrolysis, acidogenesis, acetogenesis, and hydrogen production at 55°C and 70°C, using real FW in CSTR reactors. The results obtained indicated that acidification was the rate-limiting step at both temperatures with similar process kinetics characterizations. However, the thermophilic pretreatment was more advantageous than the hyperthermophilic with suspended solids solubilization of 47.7% and 29.5% and total VFA vs. soluble COD ratio of 15.2% and 4.9%, for thermophilic and hyperthermophilic treatment, respectively, with a hydrolytic reaction time (HRT) of 10days and an OLR of 14kgCOD/m(3)d. Moreover, stable hydrogen yield (70.7ml-H2/gVSin) and content in off gas (58.6%) was achieved at HRT 5days, pH 5.5, and temperature of 55°C, as opposed to 70°C.

  9. Bioelectrochemical treatment of paper and pulp wastewater in comparison with anaerobic process: integrating chemical coagulation with simultaneous power production.

    Science.gov (United States)

    Krishna, K Vamshi; Sarkar, Omprakash; Venkata Mohan, S

    2014-12-01

    The efficiency of a bioelectrochemical treatment system (BET) to treat complex paper and pulp wastewater at two different pH conditions (6 and 7) in comparison with conventional anaerobic treatment process (AnT) was evaluated. Among the operating conditions, BET showed good treatment efficiency at pH 7 in terms of COD (BET/AnT: 55%/51%), nitrates (33.5%/19.1%), phosphates (33%/19%) and sulfates (58%/41%) in removal. The effluent obtained from BET system was subjected to coagulation for further treatment which showed good COD removal (BET/AnT, 95%/69%) and color (100%/68%). Bioelectrochemical analysis revealed higher catalytic currents in BET than AnT specific to oxidation and reduction. Besides, derivative of cyclic voltammetric scans (DCV) also supported the involvement of various membrane bound electron transferring complexes like FAD(H) bound enzymes, ubiquinone, NADH(+)/H(+) bound enzymes, etc. Experimental results demonstrated that BET system can be a viable platform to treat complex wastewaters with simultaneous energy recovery in integrated approach.

  10. Effect of Diurnally Cyclic Temperature on the Performance of a Continuous Mix Anaerobic Digester

    Directory of Open Access Journals (Sweden)

    Abdel E. Ghaly

    2011-01-01

    Full Text Available Problem statement: Concentrated livestock production is a major contributor to environmental problems through the production of large quantity of husks on relatively small land area. Anaerobic digestion represents a valuable means of cover by these husks into methane while reducing manure pollution problems. Methodology: An experimental apparatus, including data acquisition and control system, was developed and used to investigate the effects of two diurnally cyclic temperature ranges (20-40 and 15-25°C and four levels of hydraulic retention times (25, 20, 15 and 10 d on the performance of anaerobic reactors operated on screened dairy manure. Results: The reactor temperature exhibited a lag relative to the chamber temperature. For the 20-40°C temperature cycles, the average lag at the maximum chamber temperature was 3.75 h while the lag at the minimum chamber temperature was 4.37 h. For the 15-25°C temperature cycle, the average lag at maximum chamber temperatures was 3.61 while the lag of the minimum chamber temperature was 4.34 h. The effluent solids content, total Kjeldahl nitrogen and ammonium nitrogen concentrations were not adversely affected by the reactor diurnally cyclic temperature. The observed values of these parameters compared fairly well with the values obtained by other researchers. The effluent total solids, volatile suspended solids, TKN, NH4-N and methane content of the biogas diurnally cyclic patterns were out of phase with the diurnally cyclic pattern of the reactor temperature by about 12 h under most of the investigated operating conditions. The pH and the carbon dioxide content of the biogas all exhibited a diurnally cyclic pattern which was in phase with the reactor diurnally cyclic temperature. The reductions in total solids, total suspended solids, fixed suspended solids, total Kjeldahl nitrogen, ammonium nitrogen and methane yield were all significantly affected by the diurnal temperature range and hydraulic

  11. Effect of Solids Retention Time on the Denitrification Potential of Anaerobically Digested Swine Waste

    Science.gov (United States)

    Kinyua, Maureen Njoki

    Three continuously stirred tank reactors (CSTR) were operated in semi continuous mode treating swine waste using anaerobic digestion. The reactors were used to test the effect of solid retention time (SRT) on CH4 yield, total ammonia nitrogen (TAN) concentrations, % volatile solids (VS), chemical oxygen demand (COD) and volatile fatty acids (VFA) removal, readily biodegradable COD concentration and the denitrification potential for the effluent in a biological nutrient removal (BNR) system. During Phase I of the study, the three reactors were operated at the same 28 day SRT for 16 weeks. SRTs were then changed during the 12 week Phase II period. The SRTs studied were 14, 21 and 28 days, with the same organic loading rate (OLR) of 1.88 ± 0.2 kg VS/ m3-day. The reactor with the lowest SRT (14 days) had the highest VS and VFA removal at 73.6 and 67.6% and lowest TAN concentration at 0.78 g NH4+-N/L, followed by the 21 day and 28 day reactors. This was likely due to the fast microbial growth rates and substrate utilization rates in this reactor compared with the other two. The 14 day reactor had the highest CH4 yield at 0.33 m3CH 4/kg VS added and readily biodegradable COD concentration at 0.93 COD/L. The variations in CH4 yield and readily biodegradable COD concentrations between the three reactors were not statistically significant. Denitrification potential for the reactors was 1.20, 0.73 and 0.56 g COD/g N for 14, 21 and 28 day reactors, respectively, and the differences were statistically significant. None of the reactors achieved a denitrification potential of 5 g COD/g N, the amount required to use effluent of anaerobically digested swine waste as an internal carbon source in a BNR. This was attributed to operating conditions such as freezing and thawing of the raw swine waste that maximized CH4 yield and lowered the readily biodegradable COD concentration. In addition the 14 day reactor had low TAN concentrations thus increasing the denitrification potential

  12. Benefit of sodium hydroxide pretreatment of ensiled sorghum forage on the anaerobic reactor stability and methane production.

    Science.gov (United States)

    Sambusiti, C; Ficara, E; Malpei, F; Steyer, J P; Carrère, H

    2013-09-01

    The assessment of the pretreatment effect on the anaerobic digestion process is generally based on the results of batch tests, which may fail in truly predicting full-scale anaerobic reactors performance. Therefore, in this study, the effect of alkaline pretreatment on the anaerobic digestion of ensiled sorghum forage was evaluated by comparing the results of two semi-continuous CSTR (Continuously Stirred Tank Reactor) anaerobic reactors. Results showed that an alkaline pretreatment step, prior to the anaerobic digestion of ensiled sorghum forage, can have a beneficial effect both in enhancing methane production (an increase of 25% on methane production was observed, if compared to that of untreated sorghum) and in giving more stability to the anaerobic digestion process.

  13. Effects of growth hormone and testosterone therapy on aerobic and anaerobic fitness , body composition and lipoprotein profile in middle-aged men

    Directory of Open Access Journals (Sweden)

    Adam Zając

    2014-03-01

    Full Text Available Introduction. Andropause and aging are associated with neuroendocrine dysfunctions. Growth hormone and testosterone play a significant role in several processes affecting adaptation and thereby also everyday functioning. The aim of this research project was to evaluate the effects of recombinant human growth hormone and testosterone enanthate injections on body mass and body composition, aerobic and anaerobic fitness and lipid profile in middle-aged men. Materials and method. The research group was comprised of 14 men aged 45 – 60 years. Two series of laboratory analyses were performed. Independent tests were carried out at baseline and after 12 weeks of the experiment. The data were analyzed using Statistica 9.1 software. Results. A two-way repeated measures ANOVA revealed a statistically significant effect of the intervention programme on fat-free mass (η2=0.34, total body fat (η2=0.79, total cholesterol (η2=0.30, high-density lipoprotein cholesterol (η2=0.31, low-density lipoprotein cholesterol (η2=0.42, triglyceride (η2=0.28, testosterone (η2=0.52, insulin-like growth factor 1 (η2=0.47 and growth hormone (η2=0.63. Furthermore, ANOVA revealed a statistically significant effect of the rhGH and T treatment on maximal oxygen uptake (η2=0.63, anaerobic threshold (η2=0.61 and maximal work rate (η2=0.53. Conclusion. It should be emphasized that the lipid profile was affected not only by rhGH+T replacement therapy, but also by the prescribed physical activity programme. The strength and endurance fitness programme alone did not cause significant changes in body mass and composition, nor the anaerobic and aerobic capacity. On the other hand, the rhGH=T treatment stimulated these changes significantly.

  14. THE EFFECT OF CEFTRIAXONE ON THE ANAEROBIC BACTERIAL-FLORA AND THE BACTERIAL ENZYMATIC-ACTIVITY IN THE INTESTINAL-TRACT

    NARCIS (Netherlands)

    WELLING, GW; MEIJERSEVERS, GJ; HELMUS, G; VANSANTEN, E; TONK, RHJ; DEVRIESHOSPERS, HG; VANDERWAAIJ, D

    1991-01-01

    The normal flora of the intestinal tract, mainly consisting of anaerobic bacteria, protects the host against colonization by pathogenic microorganisms. Antimicrobial treatment with ceftriaxone may influence the colonic microflora and as a consequence, the protective effect. Ten healthy volunteers re

  15. The Denitrifying Biological Phosphorus Removal Performance in Anaerobic/Anoxic Sequencing Batch Reactor: The Effect of Carbon Source

    OpenAIRE

    Gürtekin, Engin; ŞEKERDAĞ, Nusret

    2015-01-01

    In this study, the effect of carbon source on denitrifying biological phosphorus removal performance in acetate and glucose fed two anaerobic/anoxic sequencinq batch reactor (SBR) was investigated. Glucose and acetate were used as the substrates. In acetate and glucose fed reactors, the COD (Chemical Oxygen Demand) removal efficiencies were 91,90% and PO4-P removal efficiencies were 87,51% respectively. These results shows that the phosphorus removal efficiency is lower in glucose fed reactor.

  16. The effect of pH and operation mode for COD removal of slaughterhouse wastewater with Anaerobic Batch Reactor (ABR

    Directory of Open Access Journals (Sweden)

    Maria Octoviane Dyan

    2015-01-01

    Full Text Available Disposal of industrial wastes in large quantities was not in accordance with today's standards of waste into environmental issues that must be overcome with proper treatment. Similarly, the abattoir wastewater that contains too high organic compounds and suspended solids. The amount of liquid waste disposal Slaughterhouse (SW with high volume also causes pollution. The research aim to resolve this problem by lowering the levels of BOD-COD to comply with effluent quality standard. Anaerobic process is the right process for slaughterhouse wastewater treatment because of high content of organic compounds that can be utilized by anaerobic bacteria as a growth medium. Some research has been conducted among abattoir wastewater treatment using anaerobic reactors such as ABR, UASB and ASBR. Our research focuses on the search for the optimum results decline effluent COD levels to match the quality standards limbah and cow rumen fluid with biodigester ABR (Anaerobic Batch Reactor. The variables used were PH of 6, 7, and 8, as well as the concentration ratio of COD: N is 400:7; 450:7, and 500:7. COD value is set by the addition of N derived from urea [CO(NH2 2]. COD levels will be measured daily by water displacement technique. The research’s result for 20 days seen that optimum PH for biogas production was PH 7,719 ml. The optimum PH for COD removal is PH 6, 72.39 %. The operation mode COD:N for biogas production and COD removal is 500:7, with the production value is 601 ml and COD removal value is 63.85 %. The research’s conclusion, the PH optimum for biogas production was PH 7, then the optimum PH for COD removal is PH 6. The optimum operation mode COD:N for biogas production and COD removal was 500:7

  17. Mixing effect on thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste

    KAUST Repository

    Ghanimeh, Sophia A.

    2012-08-01

    This paper examines the effect of mixing on the performance of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste during the start-up phase and in the absence of an acclimated seed. For this purpose, two digesters were used under similar starting conditions and operated for 235days with different mixing schemes. While both digesters exhibited a successful startup with comparable specific methane yield of 0.327 and 0.314l CH 4/gVS, continuous slow stirring improved stability by reducing average VFA accumulation from 2890 to 825mg HAc/l, propionate content from 2073 to 488mg/l, and VFA-to-alkalinity ratio from 0.32 to 0.07. As a result, the startup with slow mixing was faster and smoother accomplishing a higher loading capacity of 2.5gVS/l/d in comparison to 1.9gVS/l/d for non-mixing. Mixing equally improved microbial abundance from 6.6 to 10gVSS/l and enhanced solids and soluble COD removal. © 2012 Elsevier Ltd.

  18. Effect of substrate loading on hydrogen production during anaerobic fermentation by Clostridium thermocellum 27405.

    Science.gov (United States)

    Islam, Rumana; Cicek, Nazim; Sparling, Richard; Levin, David

    2006-09-01

    We have investigated hydrogen (H2) production by the cellulose-degrading anaerobic bacterium, Clostridium thermocellum. In the following experiments, batch-fermentations were carried out with cellobiose at three different substrate concentrations to observe the effects of carbon-limited or carbon-excess conditions on the carbon flow, H2-production, and synthesis of other fermentation end products, such as ethanol and organic acids. Rates of cell growth were unaffected by different substrate concentrations. H2, carbon dioxide (CO2), acetate, and ethanol were the main products of fermentation. Other significant end products detected were formate and lactate. In cultures where cell growth was severely limited due to low initial substrate concentrations, hydrogen yields of 1 mol H2/mol of glucose were obtained. In the cultures where growth ceased due to carbon depletion, lactate and formate represented a small fraction of the total end products produced, which consisted mainly of H2, CO2, acetate, and ethanol throughout growth. In cultures with high initial substrate concentrations, cellobiose consumption was incomplete and cell growth was limited by factors other than carbon availability. H2-production continued even in stationary phase and H2/CO2 ratios were consistently greater than 1 with a maximum of 1.2 at the stationary phase. A maximum specific H2 production rate of 14.6 mmol g dry cell(-1) h(-1) was observed. As cells entered stationary phase, extracellular pyruvate production was observed in high substrate concentration cultures and lactate became a major end product.

  19. Effects of Psychrophilic Storage on Manures as Substrate for Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Wenche Bergland

    2014-01-01

    Full Text Available The idea that storage can enhance manure quality as substrate for anaerobic digestion (AD to recover more methane is evaluated by studying storage time and temperature effects on manure composition. Volatile fatty acids (VFA and total dissolved organics (CODs were measured in full scale pig manure storage for a year and in multiple flasks at fixed temperatures, mainly relevant for colder climates. The CODs generation, influenced by the source of the pig manure, was highest initially (0.3 g COD L−1d−1 gradually dropping for 3 months towards a level of COD loss by methane production at 15°C. Methane emission was low ( 10°C in the full scale storage and almost no generation at lower temperatures (4–6°C. CODs consisted mainly of VFA, especially acetate. All VFAs were present at almost constant ratios. The naturally separated manure middle layer without sediment and coarser particles is suitable for sludge bed AD and improved further during an optimal storage time of 1–3 month(s. This implies that high rate AD can be integrated with regular manure slurry handling systems to obtain efficient biogas generation.

  20. Effects of the antimicrobial tylosin on the microbial community structure of an anaerobic sequencing batch reactor.

    Science.gov (United States)

    Shimada, Toshio; Li, Xu; Zilles, Julie L; Morgenroth, Eberhard; Raskin, Lutgarde

    2011-02-01

    The effects of the antimicrobial tylosin on a methanogenic microbial community were studied in a glucose-fed laboratory-scale anaerobic sequencing batch reactor (ASBR) exposed to stepwise increases of tylosin (0, 1.67, and 167 mg/L). The microbial community structure was determined using quantitative fluorescence in situ hybridization (FISH) and phylogenetic analyses of bacterial 16S ribosomal RNA (rRNA) gene clone libraries of biomass samples. During the periods without tylosin addition and with an influent tylosin concentration of 1.67 mg/L, 16S rRNA gene sequences related to Syntrophobacter were detected and the relative abundance of Methanosaeta species was high. During the highest tylosin dose of 167 mg/L, 16S rRNA gene sequences related to Syntrophobacter species were not detected and the relative abundance of Methanosaeta decreased considerably. Throughout the experimental period, Propionibacteriaceae and high GC Gram-positive bacteria were present, based on 16S rRNA gene sequences and FISH analyses, respectively. The accumulation of propionate and subsequent reactor failure after long-term exposure to tylosin are attributed to the direct inhibition of propionate-oxidizing syntrophic bacteria closely related to Syntrophobacter and the indirect inhibition of Methanosaeta by high propionate concentrations and low pH.

  1. Effect of pH and sulfate concentration on hydrogen production using anaerobic mixed microflora

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jae-Hoon; Choi, Jeong-A.; Bhatnagar, Amit; Kumar, Eva; Jeon, Byong-Hun [Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710 (Korea); Abou-Shanab, R.A.I. [Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710 (Korea); Department of Environmental Biotechnology, Mubarak City for Scientific Research, Alexandria (Egypt); Min, Booki [Department of Environmental Science and Engineering, Kyung Hee University, Yongin-Si, Gyeonggi-Do 446-701 (Korea); Song, Hocheol; Kim, Yong Je [Geologic Environment Division, KIGAM, Daejeon, 305-350 (Korea); Choi, Jaeyoung [Korea Institute of Science and Technology (KIST), Gangneung Institute, Gangneung 210-340 (Korea); Lee, Eung Seok [Geological Sciences, College of Arts and Sciences, Ohio University, Athens, OH 45701-2979 (United States); Um, Sukkee [School of Mechanical Engineering, Hanyang University, 17 Haengdang-Dong, Seongdong-Gu, Seoul, 133-791 (Korea); Lee, Dae Sung [Petroleum and Marine Research Department, KIGAM, Daejeon (Korea)

    2009-12-15

    The effects of varying sulfate concentrations with pH on continuous fermentative hydrogen production were studied using anaerobic mixed cultures growing on a glucose substrate in a chemostat reactor. The maximum hydrogen production rate was 2.8 L/day at pH 5.5 and sulfate concentration of 3000 mg/L. Hydrogen production and residual sulfate level decreased with increasing the pH from 5.5 to 6.2. The volatile fatty acids (VFAs) and ethanol fractions in the effluent were in the order of butyric acid (HBu) > acetic acid (HAc) > ethanol > propionic acid (HPr). Fluorescence In Situ Hybridization (FISH) analysis revealed the presence of hydrogen producing bacteria (HPB) under all pH ranges while sulfate reducing bacteria (SRB) were present at pH 5.8 and 6.2. The inhibition in hydrogen production by SRB at pH 6.2 diminished entirely by lowering to pH 5.5, at which activity of SRB is substantially suppressed. (author)

  2. Effect of operational pH on biohydrogen production from food waste using anaerobic batch reactors.

    Science.gov (United States)

    Lee, Chaeyoung; Lee, Sewook; Han, Sun-Kee; Hwang, Sunjin

    2014-01-01

    This study was performed to investigate the influence of operational pH on dark H(2) fermentation of food waste by employing anaerobic batch reactors. The highest maximum H(2) yield was 1.63 mol H(2)/mol hexoseadded at operational pH 5.3, whereas the lowest maximum H(2) yield was 0.88 mol H(2)/mol hexoseadded at operational pH 7.0. With decreasing operational pH values, the n-butyrate concentration tended to increase and the acetate concentration tended to decrease. The highest hydrogen conversion efficiency of 11.3% was obtained at operational pH 5.3, which was higher than that (8.3%) reported by a previous study (Kim et al. (2011) 'Effect of initial pH independent of operational pH on hydrogen fermentation of food waste', Bioresource Technology 102 (18), 8646-8652). The new result indicates that the dark fermentation of food waste was stable and efficient in this study. Fluorescence in situ hybridization (FISH) analysis showed that Clostridium species Cluster I accounted for 84.7 and 13.3% of total bacteria at operational pH 5.3 and pH 7.0, respectively, after 48 h operation.

  3. Effect of the solid content on anaerobic digestion of meat and bone meal.

    Science.gov (United States)

    Wu, Guangxue; Healy, Mark Gerard; Zhan, Xinmin

    2009-10-01

    The effect of the solid content on anaerobic digestion of meat and bone meal (MBM) was investigated in batch reactors at MBM solid contents of 1%, 2%, 5% and 10%. There was no significant difference in the specific methane (CH(4)) production potential with respect to the total volatile MBM solids (TVS) applied at these solid contents, which ranged from 351 to 381 ml CH(4)/g TVS. However, the highest CH(4) yield with respect to the removed volatile MBM solids (RVS) was 482 ml CH(4)/g RVS at the MBM solid content of 5%; the CH(4) yields were 384-448 ml CH(4)/g RVS at the other MBM solid contents. The lag time of CH(4) production rose with the increase in the solid content. The longer lag time at MBM solid contents of 5% and 10% was due to inhibition caused by high concentrations of volatile fatty acids (VFAs) and free ammonia in the reactors, but the inhibition was reversible. The production of VFAs during the digestion varied with solid contents: at the solid content of 1%, only acetic acid was detected; at 2%, both acetic and propionic acids were detected; and at 5% and 10%, acetic, propionic, butyric and valeric acids were detected. After 93-day digestion, the volatile MBM solid reduction was 92%, 91%, 79% and 80% at MBM solid contents of 1%, 2%, 5% and 10%, respectively.

  4. Anaerobic digestion of fish processing wastewaters with special emphasis on hydrolysis of suspended solids

    NARCIS (Netherlands)

    Palenzuela Rollón, A.

    1999-01-01

    Fish processing industries comprise an important segment of the Philippine economy. However, among other industries, they pollute lakes, rivers, and eventually, coastal waters. If their effluents are not sufficiently treated, the well-being of the country's coastal waters is threatened. In the long

  5. Process model for ammonia volatilization from anaerobic swine lagoons incorporating varying wind speeds and biogas bubbling

    Science.gov (United States)

    Ammonia volatilization from treatment lagoons varies widely with the total ammonia concentration, pH, temperature, suspended solids, atmospheric ammonia concentration above the water surface, and wind speed. Ammonia emissions were estimated with a process-based mechanistic model integrating ammonia ...

  6. Occurrence and removal of six pharmaceuticals and personal care products in a wastewater treatment plant employing anaerobic/anoxic/aerobic and UV processes in Shanghai, China.

    Science.gov (United States)

    Wang, Dan; Sui, Qian; Lu, Shu-Guang; Zhao, Wen-Tao; Qiu, Zhao-Fu; Miao, Zhou-Wei; Yu, Gang

    2014-03-01

    The occurrence and removal of six pharmaceuticals and personal care products (PPCPs) including caffeine (CF), N, N-diethyl-meta-toluamide (DEET), carbamazepine, metoprolol, trimethoprim (TMP), and sulpiride in a municipal wastewater treatment plant (WWTP) in Shanghai, China were studied in January 2013; besides, grab samples of the influent were also taken every 6 h, to investigate the daily fluctuation of the wastewater influent. The results showed the concentrations of the investigated PPCPs ranged from 17 to 11,400 ng/L in the WWTP. A low variability of the PPCP concentrations in the wastewater influent throughout the day was observed, with the relative standard deviations less than 25 % for most samples. However, for TMP and CF, the slight daily fluctuation still reflected their consumption patterns. All the target compounds except CF and DEET, exhibited poor removal efficiencies (treatment process, probably due to the low temperature in the bioreactor, which was unfavorable for activated sludge. While for the two biodegradable PPCPs, CF, and DEET, the anaerobic and oxic tank made contributions to their removal while the anoxic tank had a negative effect to their elimination. The tertiary UV treatment removed the investigated PPCPs by 5-38 %, representing a crucial polishing step to compensate for the poor removal by the biologic treatment process in winter.

  7. Modified anaerobic digestion elutriated phased treatment for the anaerobic co-digestion of sewage sludge and food wastewater.

    Science.gov (United States)

    Mo, Kyung; Lee, Wonbae; Kim, Moonil

    2017-02-01

    A modified anaerobic digestion elutriated phased treatment (MADEPT) process was developed for investigating anaerobic co-digestion of sewage sludge and food wastewater. The anaerobic digestion elutriated phased treatment (ADEPT) process is similar to a two-phase system, however, in which the effluent from a methanogenic reactor recycles into an acidogenic reactor to elutriate mainly dissolved organics. Although ADEPT could reduce reactor volume significantly, the unsolubilized solids should be wasted from the system. The MADEPT process combines thermo-alkali solubilization with ADEPT to improve anaerobic performance and to minimize the sludge disposal. It was determined that the optimal volume mixing ratio of sewage sludge and food wastewater was 4 : 1 for the anaerobic co-digestion. The removal efficiencies of total chemical oxygen demand, volatile solids, and volatile suspended solids in the MADEPT process were 73%, 70%, and 64%, respectively. However, those in the ADEPT process were only 48%, 37%, and 40%, respectively, at the same hydraulic retention time (HRT) of 7 days. The gas production of MADEPT was two times higher than that of ADEPT. The thermo-alkali solubilization increased the concentration of dissolved organics so that they could be effectively degraded in a short HRT, implying that MADEPT could improve the performance of ADEPT in anaerobic co-digestion.

  8. Effect of sex and menstrual cycle in women on starting speed, anaerobic endurance and muscle power.

    Science.gov (United States)

    Wiecek, M; Szymura, J; Maciejczyk, M; Cempla, J; Szygula, Z

    2016-03-01

    The aim of our study was to compare the indicators of starting speed, anaerobic endurance and power in women as well as men, and to investigate whether the values of these indicators differ in women during the follicular and luteal phases of the menstrual cycle. The studied group included 16 men and 16 women. The subjects performed the 20-second maximal cycling sprint test. The men performed the test twice at 14-day intervals. The women undertook the test 4 times: twice during the middle of follicular phase and twice in the middle of luteal phase in separate menstrual cycles. Hormonal changes during the menstrual cycle do not influence anaerobic performance, starting speed or anaerobic endurance in women. Anaerobic performance in men is higher than in women with similar aerobic performance expressed as VO2max/LBM (lean body mass). A lower power decrease with time was noted for women than men, with a similar time of maintaining power in both groups. This is evidence of women's better anaerobic endurance compared to men. At the same time, the men had significantly better starting speed rates than women.

  9. Evaluation of the detoxication efficiencies for acrylonitrile wastewater treated by a combined anaerobic oxic-aerobic biological fluidized tank (A/O-ABFT) process: Acute toxicity and zebrafish embryo toxicity.

    Science.gov (United States)

    Na, Chunhong; Zhang, Ying; Deng, Minjie; Quan, Xie; Chen, Shuo; Zhang, Yaobin

    2016-07-01

    Acrylonitrile (ACN) wastewater generated during ACN production has been reported to be toxic to many aquatic organisms. However, few studies have evaluated toxicity removal of ACN wastewater during and after the treatment process. In this study, the detoxication ability of an ACN wastewater treatment plant (WWTP) was evaluated using Daphnia magna, Danio rerio and zebrafish embryo. This ACN WWTP has a combined anaerobic oxic-aerobic biological fluidized tank (A/O-ABFT) process upgraded from the traditional anaerobic oxic (A/O) process. Moreover, the potential toxicants of the ACN wastewaters were identified by gas chromatography-mass spectrometry (GC-MS). The raw ACN wastewater showed high acute and embryo toxicity. 3-Cyanopyridine, succinonitrile and a series of nitriles were detected as the toxic contributors of ACN wastewater. The A/O process was effective for the acute and embryo toxicity removal, as well as the organic toxicants. However, the A/O effluent still showed acute and embryo toxicity which was attributed by the undegraded and the newly generated toxicants during the A/O process. The residual acute and embryo toxicity as well as the organic toxicants in the A/O effluent were further reduced after going through the downstream ABFT process system. The final effluent displayed no significant acute and embryo toxicity, and less organic toxicants were detected in the final effluent. The upgrade of this ACN WWTP results in the improved removal efficiencies for acute and embryo toxicity, as well as the organic toxicants.

  10. Effects of emulsified octadecanic acids on gas production and cellulolysis by the rumen anaerobic fungus, Piromyces communis M014.

    Science.gov (United States)

    Kim, Chang-H; Lee, Shin J; Ha, Jong K; Kim, Wan Y; Lee, Sung S

    2008-02-01

    Responses of the rumen anaerobic fungus, Piromyces communis M014, to octadecanic long-chain fatty acids (LCFAs) were evaluated by measuring total and hydrogen gas productions, filter paper (FP) cellulose degradation and polysaccharidase enzyme activities. Octadecanic acids (stearic acid, C(18:0); oleic acid, C(18:1); linoleic acid, C(18:2) and linolenic acid, C(18:3)) were emulsified by ultrasonication under anaerobic conditions, and added to the medium at the level of 0.001%. When P. communis M014 was grown in culture with stearic and oleic acids, the cumulative gas production, FP cellulose digestion and enzyme activities were significantly (pinhibited all of the investigated parameters, including cellulose degradation, enzyme activities and gas production, up to 168h incubation. These results indicated that stearic and oleic acids tended to have stimulatory effects on fungal cellulolysis, whereas linolenic acid caused a significant (pinhibition of gas production and cellulase enzyme activity was.

  11. Effects of dairy manure and corn stover co-digestion on anaerobic microbes and corresponding digestion performance.

    Science.gov (United States)

    Yue, Zhengbo; Chen, Rui; Yang, Fan; MacLellan, James; Marsh, Terence; Liu, Yan; Liao, Wei

    2013-01-01

    This study investigated the effects of corn stover as a supplemental feed on anaerobic digestion of dairy manure under different hydraulic retention times (HRT). The results elucidated that both HRT and corn stover supplement significantly influenced microbial community and corresponding anaerobic digestion performance. The highest biogas production of 497 mL per gram total solid loading per day was observed at a HRT of 40 days from digestion of manure supplemented with corn stover. Biogas production was closely correlated with the populations of Bacteroidetes, Clostridia and methanogens. Composition of the solid digestate (AD fiber) from the co-digestion of corn stover and dairy manure was similar to the digestion of dairy manure. However, the hydrolysis of AD fiber was significantly (P < 0.05) different among the different digestions. Both HRT and feed composition influenced the hydrolyzability of AD fiber via shifting the composition of microbial community.

  12. Anaerobic degradation of methanethiol in a process for Liquefied Petroleum Gas (LPG) biodesulfurization

    NARCIS (Netherlands)

    Leerdam, van R.C.

    2007-01-01

    Due to increasingly stringent environmental legislation car fuels have to be desulfurized to levels below 10 ppm in order to minimize negative effects on the environment as sulfur-containing emissions contribute to acid deposition (‘acid rain’) and to reduce the amount of particulates formed during

  13. Hydrogen production from the dissolution of nano zero valent iron and its effect on anaerobic digestion.

    Science.gov (United States)

    Huang, Yu-Xi; Guo, Jialiang; Zhang, Chunyang; Hu, Zhiqiang

    2016-01-01

    Nano zero valent iron (NZVI) has shown inhibition on methanogenesis in anaerobic digestion due to its reductive decomposition of cell membrane. The inhibition was accompanied by the accumulation of hydrogen gas due to rapid NZVI dissolution. It is not clear whether and how rapid hydrogen release from NZVI dissolution directly affects anaerobic digestion. In this study, the hydrogen release kinetics from NZVI (average size = 55 ± 11 nm) dissolution in deionized water under anaerobic conditions was first evaluated. The first-order NZVI dissolution rate constant was 2.62 ± 0.26 h(-1) with its half-life of 0.26 ± 0.03 h. Two sets of anaerobic digestion experiments (i.e., in the presence of glucose or without any substrate but at different anaerobic sludge concentrations) were performed to study the impact of H2 release from rapid NZVI dissolution, in which H2 was generated in a separate water bottle containing NZVI (i.e., ex situ H2 or externally supplied from NZVI dissolution) before hydrogen gas was introduced to anaerobic digestion. The results showed that the H2 partial pressure in the headspace of the digestion bottle reached as high as 0.27 atm due to rapid NZVI dissolution, resulting in temporary inhibition of methane production. Nevertheless, the 5-d cumulative methane volume in the group with ex situ H2 production due to NZVI dissolution was actually higher than that of control, suggesting NZVI inhibition on methanogenesis is solely due to the reductive decomposition of cell membrane after direct contact with NZVI.

  14. Modelling phosphorus (P), sulphur (S) and iron (Fe) interactions during the simulation of anaerobic digestion processes

    DEFF Research Database (Denmark)

    Flores-Alsina, Xavier; Solon, Kimberly; Kazadi-Mbamba, Christian;

    2015-01-01

    ) and their potential effect on total biogas production (CO2, CH4, H2 and H2S). The ADM1 version, implemented in the plant-wide context provided by the Benchmark Simulation Model No. 2 (BSM2), is used as the basic platform (A0). Four (A1 – A4) different model extensions are implemented, simulated and evaluated....... The first approach (A1) considers P transformations by accounting for the kinetic decay of polyphosphates (XPP) and potential uptake of Volatile Fatty Acids (VFA) to produce Polyhydroxyalkanoates (XPHA) by Phosphorus Accumulating Organisms (XPAO). The second model formulation (A2) describes biological...... production of sulfide (SH2S) by means of Sulfate-Reducing Bacteria (XSRB). This approach also considers potential SH2S inhibition effect on biomass and mass transfer phenomena (aqueous-gas). The third evaluated model (A3) considers chemical iron (III) (SFe+3) reduction to iron (II) (SFe+2) using hydrogen (SH...

  15. Anaerobic degradation of methanethiol in a process for Liquefied Petroleum Gas (LPG) biodesulfurization

    OpenAIRE

    Leerdam, van, J.

    2007-01-01

    Due to increasingly stringent environmental legislation car fuels have to be desulfurized to levels below 10 ppm in order to minimize negative effects on the environment as sulfur-containing emissions contribute to acid deposition (‘acid rain’) and to reduce the amount of particulates formed during the burning of the fuel. Moreover, low sulfur specifications are also needed to lengthen the lifetime of car exhaust catalysts. The research presented in this thesis focuses on the biological desul...

  16. Biohydrogen production from purified terephthalic acid (PTA) processing wastewater by anaerobic fermentation using mixed microbial communities

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ge-Fu; Wu, Peng; Wei, Qun-Shan; Lin, Jian-yi; Liu, Hai-Ning [Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China); Gao, Yan-Li [China University of Geosciences, Wuhan 430074 (China)

    2010-08-15

    Purified terephthalic acid (PTA) processing wastewater was evaluated as a fermentable substrate for hydrogen (H{sub 2}) production with simultaneous wastewater treatment by dark-fermentation process in a continuous stirred-tank reactor (CSTR) with selectively enriched acidogenic mixed consortia under continuous flow condition in this paper. The inoculated sludge used in the reactor was excess sludge taken from a second settling tank in a local wastewater treatment plant. Under the conditions of the inoculants not less than 6.3 gVSS/L, the organic loading rate (OLR) of 16 kgCOD/m{sup 3} d, hydraulic retention time (HRT) of 6 h and temperature of (35 {+-} 1) C, when the pH value, alkalinity and oxidation-reduction potential (ORP) of the effluent ranged from 4.2 to 4.4, 280 to 350 mg CaCO{sub 3}/L, and -220 to -250 mV respectively, soluble metabolites were predominated by acetate and ethanol, with smaller quantities of propionate, butyrate and valerate. Stable ethanol-type fermentation was formed with the sum of ethanol and acetate concentration ratio of 70.31% to the total liquid products after 25 days operation. The H{sub 2} volume content was estimated to be 48-53% of the total biogas and the biogas was free of methane throughout the study. The average biomass concentration was estimated to be 10.82 gVSS/L, which favored H{sub 2} production efficiently. The rate of chemical oxygen demand (COD) removal reached at about 45% and a specific H{sub 2} production rate achieved 0.073 L/gMLVSS d in the study. This CSTR system showed a promising high-efficient bioprocess for H{sub 2} production from high-strength chemical wastewater. (author)

  17. Effect of microwave hydrolysis on transformation of steroidal hormones during anaerobic digestion of municipal sludge cake.

    Science.gov (United States)

    Hamid, Hanna; Eskicioglu, Cigdem

    2013-09-15

    Fate and removal of 16 steroidal (estrogenic, androgenic and progestogenic) hormones were studied during advanced anaerobic digestion of sludge cake using microwave (MW) pretreatment. Effect of pretreatment temperature (80, 120, 160 °C), operating temperature (mesophilic at 35 ± 2 °C, thermophilic at 55 ± 2 °C) and sludge retention time (SRT: 20, 10, 5 days) were studied employing eight lab-scale semi-continuously fed digesters. To determine the potential effect of MW hydrolysis, hormones were quantified in total (sorbed + soluble) and supernatant (soluble) phases of the digester influent and effluent streams. Seven of 16 hormones were above the method reporting limit (RL) in one or more of the samples. Hormone concentrations in total phase of un-pretreated (control) and pretreated digester feeds ranged in hormones from soluble and/or total phase. MW hydrolysis of the influent resulted in both release (from sludge matrix) and attenuation of hormones in the soluble phase. Accumulation of estrone (E1) as well as progesterone (Pr) and androstenedione (Ad) in most of the digesters indicated possible microbial transformations among the hormones. Compared to controls, all pretreated digesters had lower total hormone concentrations in their influent streams. At 20 days SRT, highest total removal (E1+E2+Ad +Pr) was observed for the thermophilic control digester (56%), followed by pretreated mesophilic digesters at 120 °C and 160 °C with around 48% efficiency. In terms of conventional performance parameters, relative (to control) improvements of MW pretreated digesters at a 5-d SRT ranged in 98-163% and 57-121%, for volatile solids removal and methane production, respectively.

  18. Ammonia stripping, activated carbon adsorption and anaerobic biological oxidation as process combination for the treatment of oil shale wastewater.

    Science.gov (United States)

    Alexandre, Verônica M F; do Nascimento, Felipe V; Cammarota, Magali C

    2016-10-01

    Anaerobic biodegradability of oil shale wastewater was investigated after the following pretreatment sequence: ammonia stripping and activated carbon adsorption. Anaerobic biological treatment of oil shale wastewater is technically feasible after stripping at pH 11 for reducing the N-NH3 concentration, adsorption with 5 g/L of activated carbon in order to reduce recalcitrance and pH adjustment with CO2 so that the sulphate concentration in the medium remains low. After this pretreatment sequence, it was possible to submit the wastewater without dilution to an anaerobic treatment with 62.7% soluble chemical oxygen demand removal and specific methane production of 233.2 mL CH4STP/g CODremoved.

  19. Assessment of Ex-Vitro Anaerobic Digestion Kinetics of Crop Residues Through First Order Exponential Models: Effect of LAG Phase Period and Curve Factor

    Directory of Open Access Journals (Sweden)

    Abdul Razaque Sahito

    2013-04-01

    Full Text Available Kinetic studies of AD (Anaerobic Digestion process are useful to predict the performance of digesters and design appropriate digesters and also helpful in understanding inhibitory mechanisms of biodegradation. The aim of this study was to assess the anaerobic kinetics of crop residues digestion with buffalo dung. Seven crop residues namely, bagasse, banana plant waste, canola straw, cotton stalks, rice straw, sugarcane trash and wheat straw were selected from the field and were analyzed on MC (Moisture Contents, TS (Total Solids and VS (Volatile Solids with standard methods. In present study, three first order exponential models namely exponential model, exponential lag phase model and exponential curve factor model were used to assess the kinetics of the AD process of crop residues and the effect of lag phase and curve factor was analyzed based on statistical hypothesis testing and on information theory. Assessment of kinetics of the AD of crop residues and buffalo dung follows the first order kinetics. Out of the three models, the simple exponential model was the poorest model, while the first order exponential curve factor model is the best fit model. In addition to statistical hypothesis testing, the exponential curve factor model has least value of AIC (Akaike's Information Criterion and can generate methane production data more accurately. Furthermore, there is an inverse linear relationship between the lag phase period and the curve factor.

  20. Instrumentation and Control in Anaerobic Digestion

    DEFF Research Database (Denmark)

    has been lack of process control handles, instruments, and developed control algorithms. This has improved dramatically in the past 10 years, and all of these areas have now been addressed. The main gap in instrumentation technology has been a rapid intermediate sensor to detect overload conditions...... benchmark. There has therefore been, overall, a quantum advance in application and sophistication of instrumentation and control in anaerobic digestion, and it is an effective option for improved process loading rate and conversion efficiency....

  1. Effects of Cd(II) and Cu(II) on microbial characteristics in 2-chlorophenol-degradation anaerobic bioreactors

    Institute of Scientific and Technical Information of China (English)

    HUANG Aiqun; CHEN Hao; CHEN Ling; DAI Yalei; ZHAO Jianfu

    2008-01-01

    The effects of Cd2+ and CU2+ at 300 mg/L on anaerobic microbial communities that degrade 2.cholorophenol(2-CP) were examined. Based on the polymerase chain reaction (PCR) of 16S rDNA, bacterial community diversity and archaeal community structure were analyzed with denaturing gradient gel electrophoresis (DGGE) and cloning,respectively.Degradation capabilities of the anaerobic microbial community were drastically abated and the degradation efficiency of 2-CP was reduced to 60%after shock by Cu2+ and Cd2+, respectively.The bacterial community structure was disturbed and the biodiversity Was reduced after shock by Cu2+ and Cdz+ for 3 d.Some new metal-resistant microbes which could cope with the new condition appeared.The sequence analysis showed that there existed common Archaea species in control sludge and systems when treated with Cu2+ and Cd2+, such as Methanothrix soehngenii,Methanosaeta concilii,uncultured euryarchaeote, and so on.Both the abundance and diversity of archaeal species were altered with addition of Cd2+ and Cu2+ at high concentration.AIthough the abundance of the predominant archaeal species decreased wim Cd2+ and Cu2+ addition for 3 d.tIley recovered to some extent after 10 d.The diversity of archaeal species Was remarkably reduced after recovery for 10 d and the shift in archaeal composition seemed to be irreversible.The 2-CP-degradation anaerobic system was more sensitive to Cu2+ than Cd2+.

  2. Effects of permafrost thaw on carbon emissions under aerobic and anaerobic environments in the Great Hing'an Mountains, China.

    Science.gov (United States)

    Song, Changchun; Wang, Xianwei; Miao, Yuqing; Wang, Jiaoyue; Mao, Rong; Song, Yanyu

    2014-07-15

    The carbon (C) pool of permafrost peatland is very important for the global C cycle. Little is known about how permafrost thaw could influence C emissions in the Great Hing'an Mountains of China. Through aerobic and anaerobic incubation experiments, we studied the effects of permafrost thaw on CH4 and CO2 emissions. The rates of CH4 and CO2 emissions were measured at -10, 0 and 10°C. Although there were still C emissions below 0°C, rates of CH4 and CO2 emissions significantly increased with permafrost thaw under aerobic and anaerobic conditions. The C release under aerobic conditions was greater than under anaerobic conditions, suggesting that permafrost thaw and resulting soil environment change should be important influences on C emissions. However, CH4 stored in permafrost soils could affect accurate estimation of CH4 emissions from microbial degradation. Calculated Q10 values in the permafrost soils were significantly higher than values in active-layer soils under aerobic conditions. Our results highlight that permafrost soils have greater potential decomposability than soils of the active layer, and such carbon decomposition would be more responsive to the aerobic environment.

  3. Cleaner production of citric acid by recycling its extraction wastewater treated with anaerobic digestion and electrodialysis in an integrated citric acid-methane production process.

    Science.gov (United States)

    Xu, Jian; Su, Xian-Feng; Bao, Jia-Wei; Chen, Yang-Qiu; Zhang, Hong-Jian; Tang, Lei; Wang, Ke; Zhang, Jian-Hua; Chen, Xu-Sheng; Mao, Zhong-Gui

    2015-01-01

    To solve the pollution problem of extraction wastewater in citric acid production, an integrated citric acid-methane production process was proposed. Extraction wastewater was treated through anaerobic digestion and the anaerobic digestion effluent (ADE) was recycled for the next batch of citric acid fermentation, thus eliminating wastewater discharge and reducing water consumption. Excessive Na(+) contained in ADE could significantly inhibit citric acid fermentation in recycling and was removed by electrodialysis in this paper. Electrodialysis performance was improved after pretreatment of ADE with air stripping and activated carbon adsorption to remove precipitable metal ions and pigments. Moreover, the concentrate water was recycled and mixed with feed to improve the water recovery rate above 95% in electrodialysis treatment, while the dilute water was collected for citric acid fermentation. The removal rate of Na(+) in ADE was above 95% and the citric acid production was even higher than that with tap water.

  4. Biogas production from potato-juice, a by-product from potato-starch processing, in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors

    DEFF Research Database (Denmark)

    Fang, Cheng; Boe, Kanokwan; Angelidaki, Irini

    2011-01-01

    In this study, the utilization of potato-juice, the organic by-product from potato-starch processing, for biogas production was investigated in batch assay and in high rate anaerobic reactors. The maximum methane potential of the potato-juice determined by batch assay was 470mL-CH4/g......VS-added. Anaerobic digestion of potato-juice in an EGSB reactor could obtain a methane yield of 380mL-CH4/gVS-added at the organic loading rate of 3.2gCOD/(L-reactor.d). In a UASB reactor, higher organic loading rate of 5.1gCOD/(L-reactor.d) could be tolerated, however, it resulted in a lower methane yield of 240m...

  5. Anaerobic bio-digestion of concentrate obtained in the process of ultra filtration of effluents from tilapia processing unit

    Directory of Open Access Journals (Sweden)

    Milena Alves de Souza

    2012-02-01

    Full Text Available The objective of the present study was to evaluate the efficiency of the process of biodigestion of the protein concentrate resulting from the ultrafiltration of the effluent from a slaughterhouse freezer of Nile tilapia. Bench digesters were used with excrements and water (control in comparison with a mixture of cattle manure and effluent from the stages of filleting and bleeding of tilapias. The effluent obtained in the continuous process (bleeding + filleting was the one with highest accumulated population from the 37th day, as well as greatest daily production. Gases composition did not differ between the protein concentrates, but the gas obtained with the use of the effluent from the filleting stage presented highest methane gas average (78.05% in comparison with those obtained in the bleeding stage (69.95% and in the continuous process (70.02% or by the control method (68.59%.

  6. Eliminating methanogenic activity in hydrogen reactor to improve biogas production in a two-stage anaerobic digestion process co-digesting municipal food waste and sewage sludge.

    Science.gov (United States)

    Zhu, Heguang; Parker, Wayne; Conidi, Daniela; Basnar, Robert; Seto, Peter

    2011-07-01

    Laboratory scale two-stage anaerobic digestion process model was operated for 280 days to investigate the feasibility to produce both hydrogen and methane from a mixture feedstock (1:1 (v/v)) of municipal food waste and sewage sludge. The maximum hydrogen and methane yields obtained in the two stages were 0.93 and 9.5 mL/mL feedstock. To eliminate methanogenic activity and obtain substantial hydrogen production in the hydrogen reactor, both feedstock and mixed liquor required treatment. The heat treatment (100°C, 10 min) for feedstock and a periodical treatment (every 2-5 weeks, either heating, removal of biomass particles or flushing with air) for mixed liquor were effective in different extent. The methane production in the second stage was significantly improved by the hydrogen production in the first stage. The maximum methane production obtained in the period of high hydrogen production was more than 2-fold of that observed in the low hydrogen production period.

  7. Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

    Directory of Open Access Journals (Sweden)

    B. Orcutt

    2008-11-01

    Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal were examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species can cause the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, none of the potential intermediates considered here is able to support metabolic activity matching the measured rates.

  8. Biogenic hydrogen conversion of de-oiled jatropha waste via anaerobic sequencing batch reactor operation: process performance, microbial insights, and CO2 reduction efficiency.

    Science.gov (United States)

    Kumar, Gopalakrishnan; Lin, Chiu-Yue

    2014-01-01

    We report the semicontinuous, direct (anaerobic sequencing batch reactor operation) hydrogen fermentation of de-oiled jatropha waste (DJW). The effect of hydraulic retention time (HRT) was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L ∗ d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d) with a DJW concentration of 200 g/L, temperature 55 °C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L ∗ d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30 °C, and pH 7.0. PCR-DGGE analysis revealed that combination of cellulolytic and fermentative bacteria were present in the hydrogen producing ASBR.

  9. Biogenic Hydrogen Conversion of De-Oiled Jatropha Waste via Anaerobic Sequencing Batch Reactor Operation: Process Performance, Microbial Insights, and CO2 Reduction Efficiency

    Directory of Open Access Journals (Sweden)

    Gopalakrishnan Kumar

    2014-01-01

    Full Text Available We report the semicontinuous, direct (anaerobic sequencing batch reactor operation hydrogen fermentation of de-oiled jatropha waste (DJW. The effect of hydraulic retention time (HRT was studied and results show that the stable and peak hydrogen production rate of 1.48 L/L*d and hydrogen yield of 8.7 mL H2/g volatile solid added were attained when the reactor was operated at HRT 2 days (d with a DJW concentration of 200 g/L, temperature 55°C, and pH 6.5. Reduced HRT enhanced the production performance until 1.75 d. Further reduction has lowered the process efficiency in terms of biogas production and hydrogen gas content. The effluent from hydrogen fermentor was utilized for methane fermentation in batch reactors using pig slurry and cow dung as seed sources. The results revealed that pig slurry was a feasible seed source for methane generation. Peak methane production rate of 0.43 L CH4/L*d and methane yield of 20.5 mL CH4/g COD were observed at substrate concentration of 10 g COD/L, temperature 30°C, and pH 7.0. PCR-DGGE analysis revealed that combination of celluloytic and fermentative bacteria were present in the hydrogen producing ASBR.

  10. Biohydrogen production from cheese whey wastewater in a two-step anaerobic process.

    Science.gov (United States)

    Rai, Pankaj K; Singh, S P; Asthana, R K

    2012-07-01

    Cheese whey-based biohydrogen production was seen in batch experiments via dark fermentation by free and immobilized Enterobacter aerogenes MTCC 2822 followed by photofermentation of VFAs (mainly acetic and butyric acid) in the spent medium by Rhodopseudomonas BHU 01 strain. E. aerogenes free cells grown on cheese whey diluted to 10 g lactose/L, had maximum lactose consumption (∼79%), high production of acetic acid (1,900 mg/L), butyric acid (537.2 mg/L) and H(2) yield (2.04 mol/mol lactose; rate,1.09 mmol/L/h). The immobilized cells improved lactose consumption (84%), production of acetic acid (2,100 mg/L), butyric acid (718 mg/L) and also H(2) yield (3.50 mol/mol lactose; rate, 1.91 mmol/L/h). E. aerogenes spent medium (10 g lactose/L) when subjected to photofermentation by free Rhodopseudomonas BHU 01 cells, the H(2) yield reached 1.63 mol/mol acetic acid (rate, 0.49 mmol/L/h). By contrast, immobilized Rhodopseudomonas cells improved H(2) yield to 2.69 mol/mol acetic acid (rate, 1.87 mmol/L/h). The cumulative H(2) yield for free and immobilized bacterial cells was 3.40 and 5.88 mol/mol lactose, respectively. Bacterial cells entrapped in alginate, had a sluggish start of H(2) production but outperformed the free cells subsequently. Also, the concomitant COD reduction for free cells (29.5%) could be raised to 36.08% by immobilized cells. The data suggest that two-step fermentative H(2) production from cheese whey involving immobilized bacterial cells, offers greater substrate to- hydrogen conversion efficiency, and the effective removal of organic load from the wastewater in the long-term.

  11. Economic viability of anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

    1996-01-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  12. Menstrual Cycle Effects on Anaerobic Power, Muscular Strength, and Muscular Endurance in Trained and Untrained Females.

    Science.gov (United States)

    Rosenburg, Beth S.; And Others

    A study determined if anaerobic power, isometric strength, and isometric endurance are affected by the menstrual cycle and if endurance trained females and untrained females are affected in the same manner on these performance parameters. Subjects were healthy, normally menstruating females, ages 18-34 years who were classified as either trained…

  13. Anaerobic soil disinfestation: Carbon rate effects on tomato plant growth and organic acid production

    Science.gov (United States)

    Anaerobic soil disinfestation (ASD) is a non-chemical soil disinfestation technique proposed for the control of soil-borne pathogens, plant parasitic-nematodes, and weeds in different crops. ASD is applied in three steps: 1) Soil amendment with a labile carbon (C) source; 2) Cover the soil with tota...

  14. Effect Of Imposed Anaerobic Conditions On Metals Release From Acid-Mine Drainage Contaminated Streambed Sediments

    Science.gov (United States)

    Remediation of streams influenced by mine-drainage may require removal and burial of metal-containing bed sediments. Burial of aerobic sediments into an anaerobic environment may release metals, such as through reductive dissolution of metal oxyhydroxides. Mining-impacted aerob...

  15. Effects of ionic strength and ion pairing on (plant-wide) modelling of anaerobic digestion

    DEFF Research Database (Denmark)

    Solon, Kimberly; Flores Alsina, Xavier; Mbamba, Christian Kazadi

    2015-01-01

    and overall plant performance indicators, namely effluent quality index (EQI) and operational cost index (OCI). The acid-base equilibria implemented in the Anaerobic Digestion Model No. 1 (ADM1) are modified to account for non-ideal aqueous-phase chemistry. The model corrects for ionic strength via the Davies...... to be required when precipitation is to be modelled....

  16. The Effect of Anaerobic and Aerobic Fish Sludge Supernatant on Hydroponic Lettuce

    NARCIS (Netherlands)

    Goddek, Simon; Schmautz, Zala; Scott, Ben; Delaide, Boris; Keesman, Karel; Wuertz, Sven; Junge, Ranka

    2016-01-01

    The mobilization of nutrients from fish sludge (i.e., feces and uneaten feed) plays a key role in optimizing the resource utilization and thus in improving the sustainability of aquaponic systems. While several studies have documented the aerobic and anaerobic digestion performance of aquaculture sl

  17. Effect of Vibration Training on Anaerobic Power and Quardroceps Surface EMG in Long Jumpers

    Science.gov (United States)

    Liu, Bin; Luo, Jiong

    2015-01-01

    Objective: To explore the anaerobic power and surface EMG (sEMG) of quardrocep muscle in lower extremities after single vibration training intervention. Methods: 8 excellent male long jumpers voluntarily participated in this study. Four intervention modes were devised, including high frequency high amplitude (HFHA,30Hz,6mm), low frequency low…

  18. Repeated sprint performance and metabolic recovery curves: effects of aerobic and anaerobic characteristics.

    Science.gov (United States)

    de Aguiar, Rafael Alves; Turnes, Tiago; Santos de Oliveira Cruz, Rogério; Salvador, Amadeo Félix; Caputo, Fabrizio

    2015-05-01

    To examine the influence of aerobic and anaerobic indices on repeated sprint (RS) performance and ability (RSA), 8 sprinters (SPR), 8 endurance runners (END), and 8 active participants (ACT) performed the following tests: (i) incremental test; (ii) 1-min test to determine first decay time constant of pulmonary oxygen uptake off-kinetics and parameters related to anaerobic energy supply, lactate exchange, and removal abilities from blood lactate kinetics; and (iii) RS test (ten 35-m sprints, departing every 20 s) to determine best (RSbest) and mean (RSmean) sprint times and percentage of sprint decrement (%Dec). While SPR had a 98%-100% likelihood of having the fastest RSbest (Cohen's d of 1.8 and 1.4 for ACT and END, respectively) and RSmean (2.1 and 0.9 for ACT and END, respectively), END presented a 97%-100% likelihood of having the lowest %Dec (0.9 and 2.2 for ACT and SPR, respectively). RSmean was very largely correlated with RSbest (r=0.85) and moderately correlated with estimates of anaerobic energy supply (r=-0.40 to -0.49). RSmean adjusted for RSbest (which indirectly reflects RSA) was largely correlated with lactate exchange ability (r=0.55). Our results confirm the importance of locomotor- and anaerobic-related variables to RS performance, and highlight the importance of disposal of selected metabolic by-products to RSA.

  19. Effect of temperature on methane production from field-scale anaerobic digesters treating dairy manure

    Science.gov (United States)

    Temperature is a critical factor affecting anaerobic digestion because it influences both system heating requirements and methane production. Temperatures of 35-37°C are typically suggested for manure digestion, yet in temperate climate digesters, require a considerable amount of additional heat en...

  20. Discussion on the application of hot hydrolysis-anaerobic digestion process in sludge treatment%热水解厌氧消化工艺的分析和应用探讨

    Institute of Scientific and Technical Information of China (English)

    王平

    2015-01-01

    热水解厌氧消化工艺可提高污泥的水解效果和有机物降解率,增加沼气产量;杀灭污泥中病菌;缩短厌氧消化的停留时间、提高消化池内的污泥浓度,节省占地面积和土建工程投资;同时使消化后的污泥易于脱水,污泥体积减少。与传统的厌氧消化工艺比较,热水解厌氧消化工艺强化了污泥的减量化、稳定化、无害化和资源化的处理目标,当与后续热干化工艺结合时,可降低运行成本。从热水解技术的原理和形式出发,结合实际工程方案,对热水解厌氧消化工艺的可行性和应用中的问题进行了初步探讨。%The hot hydrolysis-anaerobic digestion process could improve sludge hydrolysis effects and organic matter removal rate,improve methane production,and eliminate germ in sludge.It could also shorten the sludge retention time in anaerobic digestion process,increase the sludge intensity in tank,and save the occupied land area and construction proj ect investment. Meanwhile,it could make the digested sludge easy for dewatering and decrease the sludge volume. Compared with traditional anaerobic digestion process, the hot hydrolysis-anaerobic digestion process could enhance the sludge treatment functions including the reduction,stability,harmless-ness,and resource recovery of sludge.When it was combined with the consequent hot drying process,it could also reduce the operation cost.Based on the principles and style of hot hydrolysis and its application in practical proj ects,this paper discussed the feasibility of hot hydrolysis-anaero-bic digestion process and the problems in its application.

  1. Ammonia tolerant inocula provide a good base for anaerobic digestion of microalgae in third generation biogas process

    DEFF Research Database (Denmark)

    Mahdy, Ahmed; Fotidis, Ioannis; Mancini, Enrico

    2017-01-01

    ) of five different algae (Chlorella vulgaris)/manure (cattle) mixtures showed that the mixture of 80/20 (on VS basis) resulted in the highest BMP value (431 mL CH4 g VS-1), while the BMP of microalgae alone (100/0) was 415 mL CH4 g VS-1. Subsequently, anaerobic digestion of those two substrates was tested...

  2. Ammonia tolerant inocula provide a good base for anaerobic digestion of microalgae in third generation biogas process

    DEFF Research Database (Denmark)

    Mahdy, Ahmed; Fotidis, Ioannis; Mancini, Enrico;

    2016-01-01

    ) of five different algae (Chlorella vulgaris)/manure (cattle) mixtures showed that the mixture of 80/20 (on VS basis) resulted in the highest BMP value (431 mL CH4 g VS-1), while the BMP of microalgae alone (100/0) was 415 mL CH4 g VS-1. Subsequently, anaerobic digestion of those two substrates was tested...

  3. Effect of temperature and organic nutrients on the biodegradation of linear alkylbenzene sulfonate (LAS) during the composting of anaerobically digested sludge from a wastewater treatment plant.

    Science.gov (United States)

    Sanz, E; Prats, D; Rodríguez, M; Camacho, A

    2006-01-01

    Limits on the application of biosolids (anaerobically processed sludges from wastewater treatment plants) as fertilizers for the amendment of soil are becoming greater because of the accumulation of recalcitrant substances, making necessary the use of techniques that bring the concentration of xenobiotics to lower concentrations than those permitted. In general, the biosolids composting process is sufficient to reduce the usual concentration of linear alkylbenzene sulfonates (LAS) to low levels. In this work, an assessment is made on the effect of temperature in the capacity of enriched bacterial populations to biodegrade LAS, together with the influence that the available nutrients may have in the biodegradation of these compounds. The results show that the microbial metabolism of LAS was not observed in the thermophilic range. The optimum temperature for the biodegradation of LAS appears to be around 40 degrees C, this is, the lowest assayed here, and at this temperature the differences in the biodegradation of LAS among the nutritionally supplemented cultures are small.

  4. Anaerobic granular sludge and biofilm reactors

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Gavala, Hariklia N.; Schmidt, Jens Ejbye

    2003-01-01

    by the immobilization of the biomass, which forms static biofilms, particle-supported biofilms, or granules depending on the reactor's operational conditions. The advantages of the high-rate anaerobic digestion over the conventional aerobic wastewater treatment methods has created a clear trend for the change......-rate anaerobic treatment systems based on anaerobic granular sludge and biofilm are described in this chapter. Emphasis is given to a) the Up-flow Anaerobic Sludge Blanket (UASB) systems, b) the main characteristics of the anaerobic granular sludge, and c) the factors that control the granulation process...

  5. Effect of electrode position on azo dye removal in an up-flow hybrid anaerobic digestion reactor with built-in bioelectrochemical system

    Science.gov (United States)

    Cui, Min-Hua; Cui, Dan; Lee, Hyung-Sool; Liang, Bin; Wang, Ai-Jie; Cheng, Hao-Yi

    2016-04-01

    In this study, two modes of hybrid anaerobic digestion (AD) bioreactor with built-in BESs (electrodes installed in liquid phase (R1) and sludge phase (R2)) were tested for identifying the effect of electrodes position on azo dye wastewater treatment. Alizarin yellow R (AYR) was used as a model dye. Decolorization efficiency of R1 was 90.41 ± 6.20% at influent loading rate of 800 g-AYR/ m3·d, which was 39% higher than that of R2. The contribution of bioelectrochemical reduction to AYR decolorization (16.23 ± 1.86% for R1 versus 22.24 ± 2.14% for R2) implied that although azo dye was mainly removed in sludge zone, BES further improved the effluent quality, especially for R1 where electrodes were installed in liquid phase. The microbial communities in the electrode biofilms (dominant by Enterobacter) and sludge (dominant by Enterococcus) were well distinguished in R1, but they were similar in R2. These results suggest that electrodes installed in liquid phase in the anaerobic hybrid system are more efficient than that in sludge phase for azo dye removal, which give great inspirations for the application of AD-BES hybrid process for various refractory wastewaters treatment.

  6. Fertilization stimulates anaerobic fuel degradation of antarctic soils by denitrifying microorganisms.

    Science.gov (United States)

    Powell, Shane M; Ferguson, Susan H; Snape, Ian; Siciliano, Steven D

    2006-03-15

    Human activities in the Antarctic have resulted in hydrocarbon contamination of these fragile polar soils. Bioremediation is one of the options for remediation of these sites. However, little is known about anaerobic hydrocarbon degradation in polar soils and the influence of bioremediation practices on these processes. Using a field trial at Old Casey Station, Antarctica, we assessed the influence of fertilization on the anaerobic degradation of a 20-year old fuel spill. Fertilization increased hydrocarbon degradation in both anaerobic and aerobic soils when compared to controls, but was of most benefit for anaerobic soils where evaporation was negligible. This increased biodegradation in the anaerobic soils corresponded with a shift in the denitrifier community composition and an increased abundance of denitrifiers and benzoyl-CoA reductase. A microcosm study using toluene and hexadecane confirmed the degradative capacity within these soils under anaerobic conditions. It was observed that fertilized anaerobic soil degraded more of this hydrocarbon spike when incubated anaerobically than when incubated aerobically. We conclude that denitrifiers are actively involved in hydrocarbon degradation in Antarctic soils and that fertilization is an effective means of stimulating their activity. Further, when communities stimulated to degrade hydrocarbons under anaerobic conditions are exposed to oxygen, hydrocarbon degradation is suppressed. The commonly accepted belief that remediation of polar soils requires aeration needs to be reevaluated in light of this new data.

  7. Transcriptional monitoring of steady state and effects of anaerobic phases in chemostat cultures of the filamentous fungus Trichoderma reesei

    Directory of Open Access Journals (Sweden)

    Penttilä Merja

    2006-10-01

    Full Text Available Abstract Background Chemostat cultures are commonly used in production of cellular material for systems-wide biological studies. We have used the novel TRAC (transcript analysis with aid of affinity capture method to study expression stability of approximately 30 process relevant marker genes in chemostat cultures of the filamentous fungus Trichoderma reesei and its transformant expressing laccase from Melanocarpus albomyces. Transcriptional responses caused by transient oxygen deprivations and production of foreign protein were also studied in T. reesei by TRAC. Results In cultures with good steady states, the expression of the marker genes varied less than 20% on average between sequential samples for at least 5 or 6 residence times. However, in a number of T. reesei cultures continuous flow did not result in a good steady state. Perturbations to the steady state were always evident at the transcriptional level, even when they were not measurable as changes in biomass or product concentrations. Both unintentional and intentional perturbations of the steady state demonstrated that a number of genes involved in growth, protein production and secretion are sensitive markers for culture disturbances. Exposure to anaerobic conditions caused strong responses at the level of gene expression, but surprisingly the cultures could regain their previous steady state quickly, even after 3 h O2 depletion. The main effect of producing M. albomyces laccase was down-regulation of the native cellulases compared with the host strain. Conclusion This study demonstrates the usefulness of transcriptional analysis by TRAC in ensuring the quality of chemostat cultures prior to costly and laborious genome-wide analysis. In addition TRAC was shown to be an efficient tool in studying gene expression dynamics in transient conditions.

  8. Impact of aluminum chloride on process performance and microbial community structure of granular sludge in an upflow anaerobic sludge blanket reactor for natural rubber processing wastewater treatment.

    Science.gov (United States)

    Thanh, Nguyen Thi; Watari, Takahiro; Thao, Tran Phuong; Hatamoto, Masashi; Tanikawa, Daisuke; Syutsubo, Kazuaki; Fukuda, Masao; Tan, Nguyen Minh; Anh, To Kim; Yamaguchi, Takashi; Huong, Nguyen Lan

    In this study, granular sludge formation was carried out using an aluminum chloride supplement in an upflow anaerobic sludge blanket (UASB) reactor treating natural rubber processing wastewater. Results show that during the first 75 days after the start-up of the UASB reactor with an organic loading rate (OLR) of 2.65 kg-COD·m(-3)·day(-1), it performed stably with a removal of 90% of the total chemical oxygen demand (COD) and sludge still remained in small dispersed flocs. However, after aluminum chloride was added at a concentration of 300 mg·L(-1) and the OLR range was increased up to 5.32 kg-COD·m(-3)·day(-1), the total COD removal efficiency rose to 96.5 ± 2.6%, with a methane recovery rate of 84.9 ± 13.4%, and the flocs began to form granules. Massively parallel 16S rRNA gene sequencing of the sludge retained in the UASB reactor showed that total sequence reads of Methanosaeta sp. and Methanosarcina sp., reported to be the key organisms for granulation, increased after 311 days of operation. This indicates that the microbial community structure of the retained sludge in the UASB reactor at the end of the experiment gave a good account of itself in not only COD removal, but also granule formation.

  9. Early-warning process/control for anaerobic digestion and biological nitrogen transformation processes: Batch, semi-continuous, and/or chemostat experiments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hickey, R. [Science Applications International Corp., McLean, VA (United States)

    1992-09-01

    The objective of this project was to develop and test an early-warning/process control model for anaerobic sludge digestion (AD). The approach was to use batch and semi-continuously fed systems and to assemble system parameter data on a real-time basis. Specific goals were to produce a real-time early warning control model and computer code, tested for internal and external validity; to determine the minimum rate of data collection for maximum lag time to predict failure with a prescribed accuracy and confidence in the prediction; and to determine and characterize any trends in the real-time data collected in response to particular perturbations to feedstock quality. Trends in the response of trace gases carbon monoxide and hydrogen in batch experiments, were found to depend on toxicant type. For example, these trace gases respond differently for organic substances vs. heavy metals. In both batch and semi-continuously feed experiments, increased organic loading lead to proportionate increases in gas production rates as well as increases in CO and H{sub 2} concentration. An analysis of variance of gas parameters confirmed that CO was the most sensitive indicator variable by virtue of its relatively larger variance compared to the others. The other parameters evaluated including gas production, methane production, hydrogen, carbon monoxide, carbon dioxide and methane concentration. In addition, a relationship was hypothesized between gaseous CO concentration and acetate concentrations in the digester. The data from semicontinuous feed experiments were supportive.

  10. [The effects of organic matter and hydrous metal oxides on the anaerobic degradation of gamma-666, p,p'-DDT in Liaohe River sediments].

    Science.gov (United States)

    Zhao, Xu; Quan, Xie; Zhao, Huimin; Chen, Shuo; Chen, Jingwen; Zhao, Yazhi

    2002-05-01

    Effects of organic matter and active Fe, Al, Mn oxides on the anaerobic degradation of gamma-666, p,p'-DDT were investigated by means of removing organic matter and hydrous metal oxides in Liaohe River sediments sequentially. The results showed that the anaerobic degradation of gamma-666, p,p'-DDT followed pseudo-first-order kinetics in different sediments; but, the extents and rates of degradation were different, even the other conditions remained same. Anaerobic degradation rates of gamma-666, p,p'-DDT were 0.020 d-1, 0.009 d-1 respectively for the sediments without additional carbon resources. However, with additional carbon resources, the anaerobic degradation rates of gamma-666, p,p'-DDT were 0.071 d-1 and 0.054 d-1 in the original sediments respectively. After removing organic matter, the rates were decreased to 0.047 d-1, 0.037 d-1. In the sediments removed organic matter and hydrous metal oxides, the rates were increased to 0.067 d-1, 0.059 d-1. This results indicated that organic matter in the sediments accelerated the anaerobic degradation of gamma-666, p,p'-DDT; the hydrous metal oxides inhibited the anaerobic degradation of gamma-666 and p,p'-DDT.

  11. Effects of nature organic matters and hydrated metal oxides on the anaerobic degradation of lindane,p,p'-DDT and HCB in sediments

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xu; QUAN Xie; ZHAO Hui-min; CHEN Jing-wen; CHEN Shou; ZHAO Ya-zhi

    2003-01-01

    Effects of natural organic matters(NOM) and hydrated metal oxides(HMO) in sediments on the anaerobic degradation of γ-666, p,p'-DDT and HCB were investigated by means of removing NOM and HMO in Liaohe River sediments sequentially. The results showed that the anaerobic degradation of γ-666, p,p'-DDT and HCB followed pseudo-first-order kinetics in different sediments; But, the extents and rates of degradation were different, even the other conditions remained the same. Anaerobic degradation rates of γ-666, p,p'-DDT and HCB were 0.020 d-1, 0.009 d-1 and 0.035 month-1 respectively for the sediments without additional carbon resources. However, with addition of carbon resources, the anaerobic degradation rates of γ-666, p, p'-DDT and HCB were 0.071d-1, 0.054d-1 and 0.088 month-1 in the original sediments respectively. After removing NOM, the rates were decreased to 0.047 d-1, 0.037 d-1 and 0.066 month-1; in the sediments removed NOM and HMO, the rates were increased to 0.067d-1, 0.059 d-1 and 0.086 month-1. These results indicated that NOM in the sediments accelerated the anaerobic degradation of γ-666, p,p'-DDT and HCB; the HMO inhibited the anaerobic degradation of γ-666, p,p'-DDT and HCB.

  12. Defined enzyme cocktail from the anaerobic fungus Orpinomyces sp. strain C1A effectively releases sugars from pretreated corn stover and switchgrass

    Science.gov (United States)

    Morrison, Jessica M.; Elshahed, Mostafa S.; Youssef, Noha H.

    2016-01-01

    The anaerobic fungus Orpinomyces strain C1A is capable of growth on various types of lignocellulosic substrates, and harbors an impressive reservoir of carbohydrate active enzymes (CAZymes). Using a minimum enzyme cocktail strategy, we constituted a four-component lignocellulolytic cocktail derived from highly transcribed C1A, and evaluated its efficacy against pretreated corn stover and switchgrass. Hydrolysis yields ranged between 65–77.4%, depending on the lignocellulosic substrate and pretreatment applied. Addition of a highly expressed anaerobic fungal swollenin improved hydrolysis yields by up to 7%. Compared to the commercial cocktail CTec2, these anaerobic fungal cocktails provided comparable or slightly lower hydrolysis yields. Further, the differences in efficacy between commercial and anaerobic cocktails were often only realized after extended (168 hr) incubations. Under certain conditions, the hydrolysis yields of the anaerobic fungal cocktail was slightly superior to that realized by CTec2. We attribute the observed high hydrolysis yields to the high specific activity and affinity of the individual enzymes of the cocktail, as well as the high level of synergy and multi-functionality observed in multiple components. Collectively, this effort provides a novel platform for constructing highly effective enzymes for biofuel production and represents the first lignocellulolytic enzyme cocktail created from anaerobic fungal enzymes. PMID:27381262

  13. Effects of aerobic-anaerobic transient conditions on sulfur and metal cycles in sewer biofilms

    NARCIS (Netherlands)

    Nielsen, A.; Lens, P.N.L.; Vollertsen, J.; Hvitved-Jacobsen, Th.

    2005-01-01

    Interactions between sulfur and metals were studied in aerobic and anaerobic biofilms grown on domestic waste water at 15°C. The dominant metals in the waste water were iron, zinc and copper, which were present in average concentrations of 0.5mg/l, 0.6mg/l and 0.1m/l, respectively. Copper and zinc w

  14. Isolation and Cultivation of Anaerobes

    DEFF Research Database (Denmark)

    Aragao Börner, Rosa

    2016-01-01

    Anaerobic microorganisms play important roles in different biotechnological processes. Their complex metabolism and special cultivation requirements have led to less isolated representatives in comparison to their aerobic counterparts.In view of that, the isolation and cultivation of anaerobic...... microorganisms is still a promising venture, and conventional methodologies as well as considerations and modifications are presented here. An insight into new methodologies and devices as well as a discussion on future perspectives for the cultivation of anaerobes may open the prospects of the exploitation...

  15. Bio-chemical process for nitrogen and phosphorus removal by draining out anaerobic rich phosphate supernatant in ERP-SBR system

    Institute of Scientific and Technical Information of China (English)

    JIFangying; XUXiaoyi; LUOGuyuan

    2003-01-01

    The method of fixed phosphate coming from anaerobic reactor by the auxiliary chemical process is applied in External Recycle Process-SBR (ERP-SBR). This process changes the model of draining out activated sludge in the traditional biological phosphorus removal system to discharge anaerobic poly-phosphate supernatant. This process eliminates the contradiction of control for Solid Removal Time (SRT) in process of biological nitrogen and phosphorus removal. It can obtain high removal efficiency of nitrogen(N) and phosphorus(P) in longer SRT. Experiment results show that: when SRT=50 ~ 80 d, TN=28.6~ 58.3 mg/L, TP=5.5~ 13.5 mg/L in influent, COD≤ 34mg/L, TN≤ 6.02 mg/L, PO43-≤0.23 mg/L in effluent. The amount of lime is only 5% of traditional methods. The phosphorus content in the chemical sludge is 12 %~15 % and the recycle of phosphorus can be realized easily.

  16. A review of anaerobic treatment of saline wastewater.

    Science.gov (United States)

    Xiao, Yeyuan; Roberts, Deborah J

    2010-01-01

    Large volumes of saline (> 2% w/v NaCl) wastewaters are discharged from many industries; e.g. seafood processing, textile dyeing, oil and gas production, tanneries and drinking water treatment processes. Although anaerobic treatment would be the most cost-effective and sustainable technology for the treatment of many of these saline wastewaters, the salinity is considered to be inhibitory to anaerobic biological treatment processes. The recent applications of salt-tolerant cultures for the treatment of wastewaters from seafood processing and ion-exchange processes suggest that biological systems can be used to treat salty wastewaters. Additionally, organisms capable of anaerobic degradation of contaminants in saline solutions have been observed in marine sediments and have been characterized during the last two decades. This manuscript provides a review of the recent research on anaerobic treatment of saline wastewater and bacterial consortia capable of the anaerobic degradation of pollutants in saline solutions, documenting that the biological treatment of saline wastewaters is promising.

  17. Anaerobic biodegradability of macropollutants

    DEFF Research Database (Denmark)

    Angelidaki, Irini

    2002-01-01

    A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors import...

  18. Decolorizing and detoxifying textile wastewater, containing both soluble and insoluble dyes, in a full scale combined anaerobic/aerobic system.

    Science.gov (United States)

    Frijters, C T M J; Vos, R H; Scheffer, G; Mulder, R

    2006-03-01

    The wastewater originating from the bleaching and dyeing processes in the textile factory Ten Cate Protect in Nijverdal (the Netherlands) was successfully treated in a sequential anaerobic/aerobic system. In the system, a combination of an anaerobic 70-m3 fluidized bed reactor and a 450-m3 aerobic basin with integrated tilted plate settlers, 80-95% of the color was removed. The color was largely removed in the preacidification basin and the anaerobic reactor. Color, deriving from both reactive as well as disperse, was anaerobically removed, indicating that these type of dyes were reduced to colorless products. Interestingly, the vat dyes, the anthraquinones and indigoids, which were thought to be removed mainly aerobically, were largely anaerobically decolorized. Apparently the anaerobic system is capable of effectively removing the color of both soluble as insoluble dyes. The treated effluent of the sequential anaerobic/aerobic treatment showed no toxicity towards the bioluminescent bacterium Vibrio fisheri (EC20 (95%) > 45%). Partially bypassing the anaerobic stage resulted in increased toxicity (EC20 (95%) of 9% and 14%) in the effluent of the aerobic treatment and caused significant decrease of color removal. The results of this study show a main contribution of anaerobic treatment in decolorizing and detoxifying the textile wastewater in the sequential anaerobic/aerobic system.

  19. The effects of aerobic and anaerobic training on fitness, blood pressure, and psychological stress and well-being.

    Science.gov (United States)

    Norris, R; Carroll, D; Cochrane, R

    1990-01-01

    To determine whether fitness alters psychological and physiological indices of well-being, male police officers were assigned to either an aerobic or anaerobic training condition or to a no treatment control group. The training groups met three times per week in 45 min sessions aimed at improving either cardiovascular endurance or muscle strength. Aerobic fitness level, heart rate, blood pressure and self-report of stress and well-being were measured prior to and following 10 weeks of training. Post-training fitness measures confirmed the effectiveness of training and between group differences for physiological and self-report measures were found. Subjects undergoing aerobic training evinced larger changes on the self-report measures of well-being and stress than the anaerobic trainers and both groups showed significant improvement when compared to controls. This experiment provides support for the hypothesis that exercise, and in particular aerobic exercise, has positive effects of well-being. It is suggested that future research might usefully explore the particular contribution of different aspects of the training situation to these effects.

  20. Biodegradability of leathers through anaerobic pathway.

    Science.gov (United States)

    Dhayalan, K; Fathima, N Nishad; Gnanamani, A; Rao, J Raghava; Nair, B Unni; Ramasami, T

    2007-01-01

    Leather processing generates huge amounts of both solid and liquid wastes. The management of solid wastes, especially tanned leather waste, is a challenging problem faced by tanners. Hence, studies on biodegradability of leather become imperative. In this present work, biodegradability of untanned, chrome tanned and vegetable tanned leather under anaerobic conditions has been addressed. Two different sources of anaerobes have been used for this purpose. The effect of detanning as a pretreatment method before subjecting the leather to biodegradation has also been studied. It has been found that vegetable tanned leather leads to more gas production than chrome tanned leather. Mixed anaerobic isolates when employed as an inoculum are able to degrade the soluble organics of vegetable tanned material and thus exhibit an increased level of gas production during the initial days, compared to the results of the treatments that received the anaerobic sludge. With chrome tanned materials, there was not much change in the volume of the gas produced from the two different sources. It has been found that detanning tends to improve the biodegradability of both types of leathers.

  1. LONG TERM EFFECTS OF DIFFERENT TRAINING MODALITIES ON POWER, SPEED, SKILL AND ANAEROBIC CAPACITY IN YOUNG MALE BASKETBALL PLAYERS

    Directory of Open Access Journals (Sweden)

    Mindaugas Balciunas

    2006-03-01

    Full Text Available The purpose of this study was to identify the effect of 4 months of different training modalities on power, speed, skill and anaerobic capacity in 15-16 year old male basketball players. Thirty five Lithuanian basketball players were randomly assigned into three groups: power endurance group (intermittent exercise, PE, n = 12, general endurance group (continuous exercise, GE, n = 11 and control group (regular basketball training, CG, n = 12. The power endurance model was based in basketball game external structure whereas the general endurance model was based in continuous actions that frequently occur during the basketball game. The training models were used for 16 weeks in sessions conducted 3 times a week during 90 minutes each in the competition period. The following tests were performed: 20 m speed run, Squat jump, Countermovement jump, Running-based Anaerobic Sprint Test (RAST, 2 min. shooting test and the Shuttle ball-dribbling test. A 3×2 repeated measures ANOVA revealed no statistically significant differences in the 20 m speed run, Squat jump and Countermovement jump (p > 0.05. On the other hand, RAST showed significant increases in PE, with greater increases during the 5th and 6th runs. The PE training model also produced a significant improvement in the shuttle ball-dribbling test (48.7 ± 1.5 in the pretest, 45.5 ± 1.3 in the posttest, p < 0.05. Globally, our results suggest that both training modalities were able to maintain initial values of speed and power, however, the anaerobic capacity and skill increased only in the players from the power endurance group. Therefore, the power endurance training (intermittent high intensity exercise may be more beneficial to prepare junior players according to the game cardiovascular and metabolic specific determinants

  2. Application of Anaerobic Digestion Model No. 1 for simulating anaerobic mesophilic sludge digestion

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, Carlos, E-mail: carllosmendez@gmail.com; Esquerre, Karla, E-mail: karlaesquerre@ufba.br; Matos Queiroz, Luciano, E-mail: lmqueiroz@ufba.br

    2015-01-15

    Highlights: • The behavior of a anaerobic reactor was evaluated through modeling. • Parametric sensitivity analysis was used to select most sensitive of the ADM1. • The results indicate that the ADM1 was able to predict the experimental results. • Organic load rate above of 35 kg/m{sup 3} day affects the performance of the process. - Abstract: Improving anaerobic digestion of sewage sludge by monitoring common indicators such as volatile fatty acids (VFAs), gas composition and pH is a suitable solution for better sludge management. Modeling is an important tool to assess and to predict process performance. The present study focuses on the application of the Anaerobic Digestion Model No. 1 (ADM1) to simulate the dynamic behavior of a reactor fed with sewage sludge under mesophilic conditions. Parametric sensitivity analysis is used to select the most sensitive ADM1 parameters for estimation using a numerical procedure while other parameters are applied without any modification to the original values presented in the ADM1 report. The results indicate that the ADM1 model after parameter estimation was able to predict the experimental results of effluent acetate, propionate, composites and biogas flows and pH with reasonable accuracy. The simulation of the effect of organic shock loading clearly showed that an organic shock loading rate above of 35 kg/m{sup 3} day affects the performance of the reactor. The results demonstrate that simulations can be helpful to support decisions on predicting the anaerobic digestion process of sewage sludge.

  3. Effects of the incorporation of drinking water sludge on the anaerobic digestion of domestic wastewater sludge for methane production.

    Science.gov (United States)

    Torres-Lozada, Patricia; Díaz-Granados, José Sánchez; Parra-Orobio, Brayan Alexis

    2015-01-01

    Water purification and wastewater treatment generate sludge, which must be adequately handled to prevent detrimental effects to the environment and public health. In this study, we examined the influence of the application of settled sludge from a drinking water treatment plant (S(DWTP)) on the anaerobic digestion (AD) of the thickened primary sludge from a municipal wastewater treatment plant (S(WWTP)) which uses chemically assisted primary treatment (CAPT). On both plants the primary coagulant is ferric chloride. The study was performed at laboratory scale using specific methanogenic activity (SMA) tests, in which mixtures of S(WWTP)-S(DWTP) with the ratios 100:00, 80:20, 75:25, 70:30 and 00:100 were evaluated. Methane detection was also performed by gas chromatography for a period of 30 days. Our results show that all evaluated ratios that incorporate S(DWTP), produce an inhibitory effect on the production of methane. The reduction in methane production ranged from 26% for the smallest concentration of S(DWTP) (20%) to more than 70% for concentrations higher than 25%. The results indicated that the hydrolytic stage was significantly affected, with the hydrolysis constant Kh also reduced by approximately 70% (0.24-0.26 day(-1) for the different ratios compared with 0.34 day(-1) for the S(WWTP) alone). This finding demonstrates that the best mixtures to be considered for anaerobic co-digestion must contain a fraction of S(DWTP) below 20%.

  4. Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

    Science.gov (United States)

    Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

    2014-11-01

    One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

  5. Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

    Directory of Open Access Journals (Sweden)

    B. Orcutt

    2008-05-01

    Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism, substrate affinity and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal was examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species causes the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, neither hydrogen nor formate is exchanged fast enough between the consortia partners to achieve measured rates of metabolic activity, but that acetate exchange might support rates that approach those observed.

  6. On-field study of anaerobic digestion full-scale plants (Part II): new approaches in monitoring and evaluating process efficiency.

    Science.gov (United States)

    Schievano, Andrea; D'Imporzano, Giuliana; Orzi, Valentina; Adani, Fabrizio

    2011-10-01

    Biogas plants need easy and practical tools for monitoring and evaluating their biological process efficiency. As soon as, in many cases, biomass supply present considerable costs, full-scale anaerobic digestion (AD) processes must approach, as much as possible, the potential biogas yield of the organic mixture fed to the biodigesters. In this paper, a new indicator is proposed (the bio-methane yield, BMY), for measuring the efficiency in full-scale AD processes, based on a balance between the biochemical methane potential (BMP) of the input biomass and the residual BMP of the output materials (digestate). For this purpose, a one-year survey was performed on three different full-scale biogas plants, in the Italian agro-industrial context, and the bio-chemical processes were fully described in order to calculate their efficiencies (BMY = 87-93%) and to validate the new indicator proposed, as useful and easily applicable tool for full-scale AD plants operators.

  7. H{sub 2}S Removal in Anaerobic digestion of Sludge by Microaerophilic Processes: Pilot Plant Experience; Eliminacion de H{sub 2}S en digestion anaerobia de lodos por procesos microaerofilico: experiencia en planta piloto

    Energy Technology Data Exchange (ETDEWEB)

    Fdz-Polanco Iniguez de la Torre, M.; Perez Elvira, S. I.; Diaz Villalobos, I.; Garcia Rodriguez, L.; Torio Acha, R.; Acevedo Alvarez, A. F.

    2009-07-01

    Anaerobic digestion of sludge produces a biogas with content in H{sub 2}S between 4.000-6.000 ppm, Removal strategies can operate at three different levels: (1) at the source (source control), (2) at process level or (3) at the end (biogas treatment). Process-level control of sulfide presents several advantages when comparing with traditional biogas treatment. Microaerophilic process consists on the supply of small amounts of oxygen in the digester in order to completely remove H{sub 2}S without affect the anaerobic process. (Author) 9 refs.

  8. A bacterial population analysis of granular sludge from an anaerobic digester treating a maize-processing waste

    Energy Technology Data Exchange (ETDEWEB)

    Howgrave-Graham, A.R.; Wallis, F.M. (Natal Univ., Pietermaritzburg (ZA). Dept. of Microbiology and Plant Pathology); Steyn, P.L. (Pretoria Univ. (South Africa))

    1991-01-01

    Microbial population studies were conducted on a dense granular sludge, with excellent settling, thickening and nutrient removal properties, from a South African clarigester treating effluent from a factory producing glucose and other carbohydrates from maize. The bacterial population comprised a heterogeneous group including acetogens, enterobacteria, sulphate-reducers, spirochaetes, heterofermentative lactobacilli and methanogens. The presence of these bacteria and lack of propionic acid and butyric acid bacteria suggests that the microbial activity of this anaerobic digester involved acetate and lactate metabolism rather than propionate or butyrate catabolism as a source of precursors for methane production. (author).

  9. Combined mesophilic anaerobic and thermophilic aerobic digestion process for high-strength food wastewater to increase removal efficiency and reduce sludge discharge.

    Science.gov (United States)

    Jang, H M; Park, S K; Ha, J H; Park, J M

    2014-01-01

    In this study, a process that combines the mesophilic anaerobic digestion (MAD) process with thermophilic aerobic digestion (TAD) for high-strength food wastewater (FWW) treatment was developed to examine the removal of organic matter and methane production. All effluent discharged from the MAD process was separated into solid and liquid portions. The liquid part was discarded and the sludge part was passed to the TAD process for further degradation. Then, the digested sludge from the TAD process was recycled back to the MAD unit to achieve low sludge discharge from the combined process. The reactor combination was operated in two phases: during Phase I, 40 d of total hydraulic retention time (HRT) was applied; during Phase II, 20 d was applied. HRT of the TAD process was fixed at 5 d. For a comparison, a control process (single-stage MAD) was operated with the same HRTs of the combined process. Our results indicated that the combined process showed over 90% total solids, volatile solids and chemical oxygen demand removal efficiencies. In addition, the combined process showed a significantly higher methane production rate than that of the control process. Consequently, the experimental data demonstrated that the combined MAD-TAD process was successfully employed for high-strength FWW treatment with highly efficient organic matter reduction and methane production.

  10. Temperature effects on fermentative hydrogen production from xylose using mixed anaerobic cultures

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chiu-Yue; Wu, Chein-Chung [BioHydrogen Laboratory, Department of Water Resource Engineering, Feng Chia University, P.O. Box 25-123, Taichung 40724 (China); Hung, Chun-Hsiung [Department of Environmental Engineering, National Chung-Hsing University, 250 Kuo-Kuang Road, Taichung 40227 (China)

    2008-01-15

    Sewage sludge microflora were anaerobically cultivated in a chemostat-type anaerobic bioreactor at temperatures of 30-55{sup o}C, a pH of 7.1 and a hydraulic retention time of 12 h to determine the hydrogen production efficiency from xylose (20 g-COD/L). It was demonstrated that hydrogen production of the enriched sewage sludge microflora (dominated by Clostridia species) was temperature-dependent in hydrogen gas content, hydrogen yield, hydrogen production rate (HPR) and specific HPR with values of 25.1-42.2% (v/v), 0.4-1.4 mol-H{sub 2}/mol-xylose, 0.06-0.24 mol-H{sub 2}/L-day and 0.02-0.10 mol-H{sub 2}/g-VSS-day, respectively, and the above values peaked whaaen being operated at 50{sup o}C. A transition temperature of 45{sup o}C existed by having a lowest hydrogen production efficiency. Butyrate and ethanol were the major soluble metabolite products for thermophilic and mesophilic fermentation, respectively. The liquid metabolite concentration fractions and microbial community analysis indicate that the differences in hydrogen production efficiency between each tested temperature might relate to the shifts in metabolic pathway or microbial community. Thermodynamic analysis using HPR values and Arrhenius equation showed that the activation energy was 74.7 kJ/mol. Strategies based on temperature control for optimal hydrogen production from xylose using natural mixed cultures are proposed. (author)

  11. Anaerobic digester foaming in full-scale cylindrical digesters--effects of organic loading rate, feed characteristics, and mixing.

    Science.gov (United States)

    Subramanian, Bhargavi; Pagilla, Krishna R

    2014-05-01

    Cylindrical anaerobic digesters (AD) were investigated to determine the causes and contributors of AD foaming due to the following: organic loading rate (OLR) and mixing effects, waste activated sludge (WAS) storage effects and foam suppression mixing at the surface of AD, and the effects of primary sludge (PS) solids fraction in the feed sludge. No foaming was observed over the duration of the study, indicating absence of a primary foaming cause even though the suspected contributors to AD foaming were present. Total solids and temperature profiles showed that reducing mixing frequency did not significantly impact digester performance or the homogeneity of the digester contents. The results showed that high organic loading rates, reduced mixing, and feed sludge storage by themselves do not cause foaming in most ADs when the primary foaming cause is absent. Reduced mixing and surface sludge sprays are practical strategies to control AD foaming.

  12. Effect of vitamin B12 pulse addition on the performance of cobalt deprived anaerobic granular sludge bioreactors

    KAUST Repository

    Fermoso, Fernando G.

    2010-07-01

    The effect of a pulse addition of vitamin B12 as cobalt source to restore the performance of cobalt depleted methanol-fed bioreactors was investigated. One upflow anaerobic sludge bed (UASB) reactor was supplied with a pulse of vitamin B12, and its operation was compared to that of another cobalt depleted UASB reactor to which a pulse of CoCl2 was given. The addition of cobalt in the form of CoCl2 supplies enough cobalt to restore methanogenesis and maintain full methanol degradation coupled to methane production during more than 35 days after the CoCl2 pulse. Similar to CoCl2, pulse addition of vitamin B12 supplies enough cobalt to maintain full methanol degradation during more than 35 days after the pulse. However, the specific methanogenic activities (SMAs) of the sludge in the vitamin B12 supplied reactor were around 3 times higher than the SMA of the sludge from the CoCl2 supplied reactor at the same sampling times. An appropriate dosing strategy (repeated pulse dosing) combined with the choice of vitamin B12 as the cobalt species is suggested as a promising dosing strategy for methanol-fed anaerobic bioreactors limited by the micronutrient cobalt. © 2010 Elsevier Ltd. All rights reserved.

  13. The Analysis of a Microbial Community in the UV/O3-Anaerobic/Aerobic Integrated Process for Petrochemical Nanofiltration Concentrate (NFC Treatment by 454-Pyrosequencing.

    Directory of Open Access Journals (Sweden)

    Chao Wei

    Full Text Available In this study, high-throughput pyrosequencing was applied on the analysis of the microbial community of activated sludge and biofilm in a lab-scale UV/O3- anaerobic/aerobic (A/O integrated process for the treatment of petrochemical nanofiltration concentrate (NFC wastewater. NFC is a type of saline wastewater with low biodegradability. From the anaerobic activated sludge (Sample A and aerobic biofilm (Sample O, 59,748 and 51,231 valid sequence reads were obtained, respectively. The dominant phylotypes related to the metabolism of organic compounds, polycyclic aromatic hydrocarbon (PAH biodegradation, assimilation of carbon from benzene, and the biodegradation of nitrogenous organic compounds were detected as genus Clostridium, genera Pseudomonas and Stenotrophomonas, class Betaproteobacteria, and genus Hyphomicrobium. Furthermore, the nitrite-oxidising bacteria Nitrospira, nitrite-reducing and sulphate-oxidising bacteria (NR-SRB Thioalkalivibrio were also detected. In the last twenty operational days, the total Chemical Oxygen Demand (COD and Total Organic Carbon (TOC removal efficiencies on average were 64.93% and 62.06%, respectively. The removal efficiencies of ammonia nitrogen and Total Nitrogen (TN on average were 90.51% and 75.11% during the entire treatment process.

  14. The Effects of Low Dose Buccal Administered Caffeine on RPE and Pain during an Upper Body Muscle Endurance Test and Lower Body Anaerobic Test

    Science.gov (United States)

    Bellar, David M.; Judge, Lawrence W.; Kamimori, Gary H.; Glickman, Ellen L.

    2012-01-01

    To date there have been a number of studies that have assessed the effects of caffeine on Rated Perceived Exertion (RPE) and Pain Scale scores during continuous exercise. Presently there is little information about the effects of caffeine on RPE and Pain Scale scores during short term, anaerobic and muscle endurance activity. The purpose of the…

  15. Short-and long-term effects of ammonia and nitrite on the anammox process

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, I.; Campos, J. L.; Mosquera-Corral, A.; Mendez, R.

    2009-07-01

    Auto trophic anaerobic ammonium oxidation (Anammox) process is a feasible alternative to treat industrial wastewater with high ammonia concentration but low content of organic matter. In this process ammonium and nitrite are used by Planctomycete-type bacteria under anoxic conditions to generate nitrogen gas. Both substrates can exert inhibitory effects on the process, causing the decrease of the specific activity of the biomass and the loss of the performance and stability of reactors. (Author)

  16. Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol Wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xuefei; REN Nanqi

    2007-01-01

    In this study,the two-stage upflow anaerobic sludge blanket(UASB)system and batch experiments were employed to evaluate the performance of anaerobic digestion for the treatment of high concentration methanol wastewater.The acid resistance of granular sludge and methanogenic bacteria and their metabolizing activity were investigated.The results show that the pH of the first UASB changed from 4.9 to 5.8 and 5.5 to 6.2 for the second reactor.Apparently,these were not the advisable pH levels that common metha nogenic bacteria could accept.The methanogenic bacteria of the system,viz.Methanosarcina barkeri,had some acid resistance and could still degrade methanol at pH 5.0.If the methanogenic bacteria were trained further,their acid resistance would be improved somewhat.Granular sludge of the system could protect the methanogenic bacteria within its body against the impact of the acidic environment and make them degrade methanol at pH 4.5.The performance of granular sludge was attributed to its structure,bacteria species,and the distribution of bacterium inside the granule.

  17. A Novel Process Configuration for Anaerobic Digestion of Source-Sorted Household Waste Using Hyper-Thermophilic Post-Treatment

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2005-01-01

    A novel reactor configuration was investigated for anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). An anaerobic hyper-thermophilic (68°C) reactor R68 was implemented as a post–treatment step for the effluent of a thermophilic reactor R1 (55°C) in order to enhance...... hydrolysis of recalcitrant organic matter, improve sanitation and ease the stripping of ammonia from the reactor. The efficiency of the combined system was studied in terms of methane yield, volatile solids (VS) reduction and volatile fatty acid (VFA) production at different hydraulic retention times (HRT......). A single-stage thermophilic (55°C) reactor R2 was used as control. VS reduction and biogas yield of the combined system was 78 – 89% and 640 – 790 ml/g-VS, respectively. While the VS reduction in the combined system was up to 7% higher than in the single-stage treatment, no increase in methane yield...

  18. The effects of salinization on aerobic and anaerobic decomposition and mineralization in peat meadows: the roles of peat type and land use.

    Science.gov (United States)

    Brouns, Karlijn; Verhoeven, Jos T A; Hefting, Mariet M

    2014-10-01

    Peat soils comprise a large part of the western and northern Netherlands. Drainage for agriculture has caused increased soil aeration which has stimulated decomposition and, hence, soil subsidence, currently amounting to 1-2 cm/yr. River water is supplied to these peat areas in summer to prevent drying out of the peat soils. Saltwater intrusion and evaporation make this surface water slightly brackish during drought periods. In addition, brackish seepage can surface more easily during such dry periods. We performed an incubation experiment in which the effects of salinization on aerobic decomposition and mineralization of shallow peat samples and anaerobic decomposition and mineralization of deep peat samples were studied. We considered four different types of peat samples: peat sampled in agricultural peat meadows and in nature reserves, originally formed under either eutrophic or oligotrophic conditions. The aerobic decomposition was approximately reduced by 50% after salinization, whereas the anaerobic decomposition rates remained unchanged. Remarkably, the response to salinization did not differ between the peat types and land uses. Ammonium concentrations increased while nitrate concentrations decreased after salinization, probably as a result of reduced nitrification. Especially in the oligotrophic peat, ammonium concentrations increased substantially. Phosphate concentrations increased, possibly caused by changes in desorption and adsorption processes due to higher ion concentrations. DOC concentrations decreased in the brackish samples due to precipitation. Furthermore, the eutrophic peat samples showed increasing sulfate concentrations, both in oxic and anoxic incubations, which was attributed to pyrite oxidation. Independently of salinization, nitrification rates were higher in the agricultural, fertilized, peat soils. In conclusion, while salinization might reduce subsidence rates, it will have adverse effects on water quality.

  19. Effects of Residual Hypochlorite Ion on Methane Production during the Initial Anaerobic Digestion Stage of Pig Slurry.

    Science.gov (United States)

    Yoon, Young-Man; Kim, Hyun-Cheol; So, Kyu-Ho; Kim, Chang-Hyun

    2013-01-01

    The hypochlorite ion (OCl(-)) is a widely used disinfecting agent in pig rearing in Korea, but its residual effect on CH4 production from pig slurry is unclear. The objective of this study was to investigate the inhibition effects of residual OCl(-) on CH4 production during the initial anaerobic digestion stage of pig slurry. Three organic concentrations (9.9, 26.2 and 43.7 g/L) of volatile solids (VS) were tested with the addition of 52.3 mg/L OCl(-), ten times of the typical concentration used in Korea, or without OCl(-) (Control) in anaerobic batch culture. The culture was run under mesophilic (38°C) conditions for 20 d. At the lowest organic concentration with OCl(-), the VS degradation was 10.3% lower (pOCl(-), it did not differ from Control. CH4 yields were higher in the control treatments than their OCl(-) counterpart cultures, and CH4 yields of Control and OCl(-) treatments at the organic concentrations of 9.9, 26.2 and 43.7 g/L differed in the probability level (p) of 0.31, 0.04, and 0.06, respectively. Additionally, CH4 concentration increased steeply and reached 70.0% within 4 d in the absence OCl(-), but a gradual increase up to 60.0% was observed in 6 d in the OCl(-) treated cultures. The Rm (the maximum specific CH4 production rate) and λ (lag phase time) of 9.9 g/L with OCl(-) were 8.1 ml/d and 25.6 d, while the Rm was increased to 15.1 ml/d, and λ was reduced to 11.4 d in PS-III (higher organic concentration) with OCl(-). The results suggest that a prolonged fermentation time was necessary for the methanogens to overcome the initial OCl(-) inhibitory effect, and an anaerobic reactor operated with high organic loadings was more advantageous to mitigate the inhibitory effect of residual hypochlorite ion.

  20. The Effect of Colostrum along with Aerobic and Anaerobic Exercise on Lipid Peroxidation and Total Antioxidant Capacity of Male Wistar Rats

    Directory of Open Access Journals (Sweden)

    M Mogharnasi

    2016-06-01

    Full Text Available Background & aim: The consumption of food supplements in order to eliminate oxidative damages induced by exercise are common among athletes. Previous studies have shown that bovine colostrum has antioxidant properties, but no study has ever been done to evaluate its effectiveness on Oxidative stress and antioxidant capacity. The aim of study was to investigate the effects of bovine colostrum along with aerobic and anaerobic exercise on Lipid peroxidation and antioxidant capacity in male Wistar rats.   Methods: In the present experimental study, 48 male Wistar rats were randomly divided into six groups (control, colostrum supplement, aerobic exercise, anaerobic exercise, colostrum supplements and aerobic exercise, colostrum supplements and anaerobic exercise. Colostrum group received daily for ten weeks dosing 300 mg /kg bovine colostrum powder orally. Exercising groups worked out three times a week for a period of 10 weeks on a custom-made treadmill for rodents. Blood samples were taken before and 24 hours after the last exercise session on an empty stomach. Data were analyzed using Kolmogorov-Smirnov tests, One Way ANOVA and post hoc Tukey at α<0.05.   Results: The plasma levels of oxidative stress index (MDA in all groups except colostrum supplement and anaerobic exercise compared with the control group was significantly reduced (p<0.05. The antioxidant capacity in all groups except anaerobic exercise group compared with the control group was significant increased (p<0.05.   Conclusions: The results indicated that colostrum supplementation with ten weeks of aerobic exercise had better effect on the control of oxidative stress and antioxidant capacity compared to anaerobic exercise.    

  1. Effects of biodegradation of mecoprop, dichlorprop and bentazone by changing the redox conditions from anaerobic to aerobic in sandy aquifer

    DEFF Research Database (Denmark)

    Levi, Suzi; Bjerg, Poul Løgstrup; Albrechtsen, Hans-Jørgen

    2011-01-01

    in combination with geological variations may affect microbial degradation processes by mixing in even low oxygen concentrations and create steep gradients and drastic redox zones in aquifers. The aim of the current study was to investigate the stimulation of pesticides biodegradation by adding oxygen...... knowledge, this is the first observation of bentazone degradation with aquifer. Optimization of redox conditions from anaerobic to aerobic by adding oxygen stimulated the biodegradation of three pesticides.......Pesticides and metabolites are detected in an increasing number of aquifers resulting in closure of many drinking water wells. The natural redox conditions of aquifers are considered to be one of the important factors governing the pesticides degradation in groundwater. Water abstraction strategy...

  2. Improvement of anaerobic digestion of sludge

    Energy Technology Data Exchange (ETDEWEB)

    Dohanyos, Michael; Zabranska, Jana; Kutil, Josef; Jenicek, Pavel

    2003-07-01

    Anaerobic digestion improvement can be accomplished by different methods. Besides optimization of process conditions is frequently used pretreatment of input sludge and increase of process temperature. Thermophilic process brings a higher solids reduction and biogas production, the high resistance to foaming, no problems with odour, the higher effect of destroying pathogens and the improvement of the energy balance of the whole treatment plant. Disintegration of excess activated sludge in lysate centrifuge was proved in full-scale conditions causing increase of biogas production. The rapid thermal conditioning of digested sludge is acceptable method of particulate matter disintegration and solubilization. (author)

  3. Succession of lignocellulolytic bacterial consortia bred anaerobically from lake sediment

    NARCIS (Netherlands)

    Korenblum, Elisa; Jiménez Avella, Diego; van Elsas, Jan

    2016-01-01

    Anaerobic bacteria degrade lignocellulose in various anoxic and organically rich environments, often in a syntrophic process. Anaerobic enrichments of bacterial communities on a recalcitrant lignocellulose source were studied combining polymerase chain reaction–denaturing gradient gel electrophoresi

  4. Improved Monitoring of Semi-Continuous Anaerobic Digestion of Sugarcane Waste: Effects of Increasing Organic Loading Rate on Methanogenic Community Dynamics

    Directory of Open Access Journals (Sweden)

    Athaydes Francisco Leite

    2015-09-01

    Full Text Available The anaerobic digestion of filter cake and its co-digestion with bagasse, and the effect of gradual increase of the organic loading rate (OLR from start-up to overload were investigated. Understanding the influence of environmental and technical parameters on the development of particular methanogenic pathway in the biogas process was an important aim for the prediction and prevention of process failure. The rapid accumulation of volatile organic acids at high OLR of 3.0 to 4.0 gvs·L−1·day−1 indicated strong process inhibition. Methanogenic community dynamics of the reactors was monitored by stable isotope composition of biogas and molecular biological analysis. A potential shift toward the aceticlastic methanogenesis was observed along with the OLR increase under stable reactor operating conditions. Reactor overloading and process failure were indicated by the tendency to return to a predominance of hydrogenotrophic methanogenesis with rising abundances of the orders Methanobacteriales and Methanomicrobiales and drop of the genus Methanosarcina abundance.

  5. Improved Monitoring of Semi-Continuous Anaerobic Digestion of Sugarcane Waste: Effects of Increasing Organic Loading Rate on Methanogenic Community Dynamics

    Science.gov (United States)

    Leite, Athaydes Francisco; Janke, Leandro; Lv, Zuopeng; Harms, Hauke; Richnow, Hans-Hermann; Nikolausz, Marcell

    2015-01-01

    The anaerobic digestion of filter cake and its co-digestion with bagasse, and the effect of gradual increase of the organic loading rate (OLR) from start-up to overload were investigated. Understanding the influence of environmental and technical parameters on the development of particular methanogenic pathway in the biogas process was an important aim for the prediction and prevention of process failure. The rapid accumulation of volatile organic acids at high OLR of 3.0 to 4.0 gvs·L−1·day−1 indicated strong process inhibition. Methanogenic community dynamics of the reactors was monitored by stable isotope composition of biogas and molecular biological analysis. A potential shift toward the aceticlastic methanogenesis was observed along with the OLR increase under stable reactor operating conditions. Reactor overloading and process failure were indicated by the tendency to return to a predominance of hydrogenotrophic methanogenesis with rising abundances of the orders Methanobacteriales and Methanomicrobiales and drop of the genus Methanosarcina abundance. PMID:26404240

  6. BIOGAS PROCTION FROM ANAEROBIC CO-DIGESTION OF COW DUNG AND ORGANIC WASTES (NAPIER PAK CHONG I AND FOOD WASTE IN THAILAND: TEMPERATURE EFFECT ON BIOGAS PRODUCT

    Directory of Open Access Journals (Sweden)

    Lertluck Saitawee

    2014-01-01

    Full Text Available Biogas production has been attracting increasing attention as a biofuel of the future because biogas technology not only constitutes a biofuel source, but also can be applied in the various environmental pollutants. Anaerobic digestion of high solid slurries (such as food waste and cow dung is typically performed in continuously reactor (by force substrate flow to avoid problems with a thick floating layer or large amounts of sediments. Temperature also seems to have profound influence on the biogas production. The objective of the study was to identify the optimum biogas production for anaerobic co-digestion of cow dung and organic wastes (napierpakchong I and food waste. Influence of temperature (psyhrophilic temperature 25°C and thermoplilic temperature 45°C and active biogas process on single substrate (food waste feed and co-digestion of cow dung and organic wastes (napierpakchong I and food waste was used, within the reactor was studies in 1.80 cm high over a 45 day. Results showed that best digestion was achieved when digested of cow dung, napierpakchong I and food waste on 1:1:1 and thermoplilic temperature. Maximum biogas production (R4, biogas yield, methane content and %VS reduction was found that 70 L/day, 70 L/VS feed, 65 and 80%, respectively. The result showed that the biogas production increased progressively withhigher temperature.The increased in biogas production in thermophilic temperature and psyhrophilic temperature could be up 28.01 and 26%, respectively. The biogas yield increased 12.5% of co-digestion system, which compared to thermophilic temperature and psyhrophilic temperature (R4 and R2. This behavior might be due to the higher degradability. Therefore, temperature of digester can be used effectively as an operating strategy to optimize biogas production.

  7. Long-term glycine propionyl-l-carnitine supplemention and paradoxical effects on repeated anaerobic sprint performance

    Directory of Open Access Journals (Sweden)

    Goldstein Erica R

    2010-10-01

    Full Text Available Abstract Background It has been demonstrated that acute GPLC supplementation produces enhanced anaerobic work capacity with reduced lactate production in resistance trained males. However, it is not known what effects chronic GPLC supplementation has on anaerobic performances or lactate clearance. Purpose The purpose of this study was to examine the long-term effects of different dosages of GPLC supplementation on repeated high intensity stationary cycle sprint performance. Methods Forty-five resistance trained men participated in a double-blind, controlled research study. All subjects completed two testing sessions, seven days apart, 90 minutes following oral ingestion of either 4.5 grams GPLC or 4.5 grams cellulose (PL, in randomized order. The exercise testing protocol consisted of five 10-second Wingate cycle sprints separated by 1-minute active recovery periods. Following completion of the second test session, the 45 subjects were randomly assigned to receive 1.5 g, 3.0 g, or 4.5 g GPLC per day for a 28 day period. Subjects completed a third test session following the four weeks of GPLC supplementation using the same testing protocol. Values of peak power (PP, mean power (MP and percent decrement of power (DEC were determined per bout and standardized relative to body mass. Heart rate (HR and blood lactate (LAC were measured prior to, during and following the five sprint bouts. Results There were no significant effects of condition or significant interaction effects detected for PP and MP. However, results indicated that sprint bouts three, four and five produced 2 - 5% lower values of PP and 3 - 7% lower values of MP with GPLC at 3.0 or 4.5 g per day as compared to baseline values. Conversely, 1.5 g GPLC produced 3 - 6% higher values of PP and 2 -5% higher values of MP compared with PL baseline values. Values of DEC were significantly greater (15-20% greater across the five sprint bouts with 3.0 g or 4.5 g GPLC, but the 1.5 g GPLC

  8. Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal

    Institute of Scientific and Technical Information of China (English)

    A.R. Majdi Nasab; S.M. Soleymani; M. Nosrati; S.M. Mousavi

    2016-01-01

    A pilot scale modified step-feed process was improved to increase nutrient (N and P) and organic removal operations from municipal wastewater. It combined the step-feed process and a method named“University of Cape Town (UCT)”. The effect of nutrient ratios and inflow distribution ratios were studied. The highest uptake efficiency of 95%for chemical oxygen demand (COD) has been achieved at the inflow distribution ratio of 40/35/25. However, maximum removal efficiency obtained for total nitrogen (TN) and phosphorus at 93%and 78%, respectively. The average mixed liquor suspended solids (MLSS) was 5500 mg·L−1. In addition, convenient values for dissolved oxygen (DO) concentration, and pH were obtained throughout different stages. The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal, sturdy sludge settle ability and COD removal.

  9. Thermophillic treatment by anaerobic granular sludge as an effective approach to accelerate the electron transfer and improve the reductive decolorization of azo dyes in bioreactors

    NARCIS (Netherlands)

    Santos, dos A.B.; Traverse, J.; Cervantes, F.J.; Lier, van J.B.

    2005-01-01

    The effects of temperature, hydraulic retention time (HRT), and the redox mediator, thraquinone- 2,6-disulfonate (AQDS), on electron transfer and subsequent reductive decolorization of dyes rom textile wastewater was assessed in mesophilic and thermophilic anaerobic bioreactors. The results clearly

  10. Effect of substrate and cation requirement on anaerobic volatile fatty acid conversion rates at elevated biogas pressure.

    Science.gov (United States)

    Lindeboom, Ralph E F; Ferrer, Ivet; Weijma, Jan; van Lier, Jules B

    2013-12-01

    This work studied the anaerobic conversion of neutralized volatile fatty acids (VFA) into biogas under Autogenerative High Pressure Digestion (AHPD) conditions. The effects of the operating conditions on the biogas quality, and the substrate utilisation rates were evaluated using 3 AHPD reactors (0.6 L); feeding a concentration of acetate and VFA (1-10 g COD/L) corresponding to an expected pressure increase of 1-20 bar. The biogas composition improved with pressure up to 4.5 bar (>93% CH4), and stabilized at 10 and 20 bar. Both, acetotrophic and hydrogenotrophic methanogenic activity was observed. Substrate utilisation rates of 0.2, 0.1 and 0.1 g CODCH4/g VSS/d for acetate, propionate and butyrate were found to decrease by up to 50% with increasing final pressure. Most likely increased Na(+)-requirement to achieve CO2 sequestration at higher pressure rather than end-product inhibition was responsible.

  11. Effect of Mixing Driven by Siphon Flow: Parallel Experiments Using the Anaerobic Reactors with Different Mixing Modes

    Directory of Open Access Journals (Sweden)

    Kai-Qin Xu

    2013-08-01

    Full Text Available The effect of mixing by siphon flow on anaerobic digestion, sludge distribution and microbial community were examined in parallel experiments using a siphon-mixed reactor (SMR, an unmixed reactor (UMR and a continuously mixed reactor (CMR. The SMR performed well without the accumulation of fatty acids under COD loading rates varying from 3 to 18 kg/m3/day, while the UMR was totally acidified when the loading rate increased to 10 kg/m3/day. The methane yield of the SMR was at least 10% higher than that of the UMR, and comparable to that of the CMR. Furthermore, the SMR was found to markedly improve the dispersion of solids and reduce deposit formation compared to the UMR. Besides, during stable operation, the fatty acids level in the effluent of the SMR and UMR was lower than that in the CMR, and the archaeal community structure of the SMR was similar to that of the UMR.

  12. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    Science.gov (United States)

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity.

  13. Effects of solution conditions on the physicochemical properties of stratification components of extracellular polymeric substances in anaerobic digested sludge

    Institute of Scientific and Technical Information of China (English)

    Dongqin Yuan; Yili Wang

    2013-01-01

    The composition and effects of solution conditions on the physicochemical properties of the stratification components of extracellular polymeric substances (EPS) in anaerobic digested sludge were determined.The total EPS in anaerobic digested sludge were extracted by the cation exchange resin method.Another EPS extraction method,the centrifugation and sonication technique was employed to stratify the EPS into three fractions:slime,loosely bound (LB)-EPS,and tightly bound (TB)-EPS from the outside to the inside of the anaerobic digested sludge.Proteins and polysaccharides were dispersed uniformly across the different EPS fractions,and humic-like substances were mainly partitioned in the slime,with TB-EPS second.Protein was the major constituent of the LB-EPS and TB-EPS,and the corresponding ratios ranged from 54.0% to 65.6%.The hydrophobic part in the EPS chemical components was primarily comprised of protein and DNA,while the hydrophilic part was mainly composed of polysaccharide.In the slime,the hydrophobic values of several EPS chemical components (protein,polysaccharide,humic-like substances and DNA) were all below 50%.The protein/polysaccharide ratio had a significant influence on the Zeta potentials and isoelectric point values of the EPS:the greater the protein/polysaccharide ratio of the EPS was,the greater the Zeta potential and the higher the isoeleetric point value were.All Zeta potentials of the EPS showed a decreasing trend with increasing pH.The corresponding isoeleetric point values (pH) were 2.8 for total EPS,2.2 for slime,2.7 for LB-EPS,and 2.6 for TB-EPS.As the ionic strength increased,the Zeta potentials sharply increased and then gradually became constant without charge reversal.In addition,as the temperature increased (< 40℃),the apparent viscosity of the EPS decreased monotonically and then gradually became stable between 40 and 60℃.

  14. 鸡粪厌氧发酵沼液达标处理工艺研究%Treatment Process of Anaerobically Digested Effluent of Chicken Manure for Meeting the Discharging Standard

    Institute of Scientific and Technical Information of China (English)

    王峰; 严潇南; 杨海真

    2012-01-01

    为解决鸡场沼气工程沼液后续处理问题,以某养鸡场沼气工程全混式发酵池出水沼液处理为例,研究鸡粪厌氧发酵沼液的达标处理工艺.从鸡粪厌氧发酵沼液的特点出发,采用生化法与物化法相结合工艺处理沼液,并考查了3种不同组合的工艺处理效果.先以小试试验确定工艺最佳运行参数,再中试运行考查工艺的处理效果.结果表明:采用鸟粪石- SBR -混凝工艺处理鸡粪厌氧发酵沼液,沼液CODCr由9 200 mg/L降至280 mg/L,NH4+-N由3 200 mg/L降至36 mg/L,TP由270 mg/L降至3.3 mg/L,达到畜禽养殖业污染物排放标准(GB 18596-2001);对于鸡粪厌氧发酵沼液中NH4+-N的去除,直接采用SBR处理,微生物会受到游离氨抑制,NH4+-N去除率不足30%,生化处理前必须采用预处理降低NH4+-N负荷;鸡粪厌氧发酵沼液生化性良好,但仍含有一定量难降解 CODCr,,采用生化处理结合物化工艺进行深度处理可以以较低成本实现达标排放.%To solve subsequent treating problems of cbicken farm biogas project slurry, a research was carried out on treatment processes of anaerobically digested effluent of chicken manure for meeting the discharging standard-a case study of treatment of CSTR fermentation tank effluent of a biogas project. Based on the characteristics of anaerobically digested effluent of chicken manure, bio-chemical treatment combined with physical-chemical process was used to treat the biogas slurry. In addition, effects of three different processes combination method were investigated. First, bench scale experiment was carried out to determine the optimal operation parameters , and then pilot scale devices were introduced to examine the effect of the process. Results showed when using struvite - SBR - coagulation process treating anaerobically digested effluent of chicken manure, C0DCr decreased from 9 200 mg/L to 280 mg/L, NH4+-N decreased from 3 200 mg/L to 36 mg/L, TP decreased from 270 mg

  15. Impact of nickel and cobalt on biogas production and process stability during semi-continuous anaerobic fermentation of a model substrate for maize silage.

    Science.gov (United States)

    Pobeheim, Herbert; Munk, Bernhard; Lindorfer, Harald; Guebitz, Georg M

    2011-01-01

    The importance of nickel and cobalt on anaerobic degradation of a defined model substrate for maize was demonstrated. Five semi-continuous reactors were operated for 250 days at 35 °C and a well-defined trace metal solution was added to all reactors. Two reactors each were limited regarding the concentration of Ni(2+) and Co(2+), respectively, for certain time intervals. The required nickel concentration was depending on the organic loading rates (OLR) while, for example, above 2.6 g ODM L(-1) d(-1) nickel concentrations below 0.06 mg kg(-1) FM in the process significantly decreased biogas production by up to 25% compared to a control reactor containing 0.8 mg Ni(2+) kg(-1) FM. Similarly, limitation of cobalt to 0.02 mg kg(-1) FM decreased biogas production by about 10%. Limitations of nickel as well as cobalt lead to process instability. However, after gradual addition of nickel till 0.6 mg and cobalt till 0.05 mg kg(-1) FM the OLR was again increased to 4.3 g ODM L(-1) d(-1) while process stability was recovered and a fast metabolisation of acetic and propionic acid was detected. An increase of nickel to 0.88 mg kg(-1) FM did not enhance biogas performance. Furthermore, the increase of cobalt from 0.05 mg kg(-1) FM up to 0.07 mg kg(-1) FM did not exhibit a change in anaerobic fermentation and biogas production.

  16. Comparison of start-up strategies and process performance during semi-continuous anaerobic digestion of sugarcane filter cake co-digested with bagasse.

    Science.gov (United States)

    Janke, Leandro; Leite, Athaydes F; Nikolausz, Marcell; Radetski, Claudemir M; Nelles, Michael; Stinner, Walter

    2016-02-01

    The anaerobic digestion of sugarcane filter cake and the option of co-digestion with bagasse were investigated in a semi-continuous feeding regime to assess the main parameters used for large-scale process designing. Moreover, fresh cattle manure was considered as alternative inoculum for the start-up of biogas reactors in cases where digestate from a biogas plant would not be available in remote rural areas. Experiments were carried out in 6 lab-scale semi-continuous stirred-tank reactors at mesophilic conditions (38±1°C) while the main anaerobic digestion process parameters monitored. Fresh cattle manure demonstrated to be appropriate for the start-up process. However, an acclimation period was required due to the high initial volatile fatty acids concentration (8.5gL(-1)). Regardless the mono-digestion of filter cake presented 50% higher biogas yield (480mLgVS(-1)) than co-digestion with bagasse (320mLgVS(-1)) during steady state conditions. A large-scale co-digestion system would produce 58% more biogas (1008m(3)h(-1)) than mono-digestion of filter cake (634m(3)h(-1)) due to its higher biomass availability for biogas conversion. Considering that the biogas production rate was the technical parameter that displayed the most relevant differences between the analyzed substrate options (0.99-1.45m(3)biogasm(3)d(-1)). The decision of which substrate option should be implemented in practice would be mainly driven by the available construction techniques, since economically efficient tanks could compensate the lower biogas production rate of co-digestion option.

  17. Anaerobic co-digestion of cork based oil sorbent and cow manure or sludge

    OpenAIRE

    Cavaleiro, A. J.; Neves, T. M.; Guedes, Ana P.; Alves, M.M.; Pinto, P.; Silva, S.P.; Sousa, D.Z.

    2015-01-01

    Cork, a material with great economic, social and environmental importance in Portugal, is also a good oil sorbent that can be used in the remediation of oil spills. The oil-impregnated cork can be easily removed, but requires further treatment. In the case of vegetable oil spills, anaerobic digestion may be a potential solution. This study aims to evaluate the effect of adding cork contaminated with sunflower oil as co-substrate in anaerobic digestion processes. Biodegradability assays were p...

  18. Evaluation of the matrix effect of thermophilic anaerobic digestion on inactivation of infectious laryngotracheitis virus using real-time PCR and viral cell culture.

    Science.gov (United States)

    Gao, Tiejun; Bowlby, Evelyn; Tong, Yupin; Wu, John T Y; Wong, Lester; Tower, Robert J; Pang, Xiaoli; Li, Xiaomei

    2012-04-01

    The matrix effect of the thermophilic anaerobic digestion (TAD) process on inactivation of infectious laryngotracheitis virus (ILTV) was evaluated. Viral cell culture and real-time PCR were used for assessing removal of the viral infectivity and degradation of viral DNA, respectively. Results showed that the TAD-derived matrix alone can inactivate the virus and destroy the nucleic acid helix core of ILTV in a time-and- dose-dependent manner. No cytopathogenic effect (CPE) was observed in the cells exposed to ILTV pre-treated with TAD matrix for 1.5h in experiment 1 and for 16h in experiment 2. There was a significant statistical difference between TAD matrix treated and non-treated cultures (p<0.001, Chi-test). Amplifiable ILT viral DNA was reduced 2.27 log by 1.5h-treatment and was not present by 16h-treatment with TAD matrix, indicating complete viral DNA fragmentation. The TAD process is an environmentally friendly way for disposing of poultry biowaste and carcasses.

  19. Effect of dye structure and redox mediators on anaerobic azo and anthraquinone dye reduction

    Directory of Open Access Journals (Sweden)

    Mayara Carantino Costa

    2012-01-01

    Full Text Available We investigated the biological decolourisation of dyes with different molecular structures. The kinetic constant values (k1 achieved with azo dye Reactive Red 120 were 7.6 and 10.1 times higher in the presence of RM (redox mediators AQDS and riboflavin, respectively, than the assays lacking RM. The kinetic constant achieved with the azo dye Congo Red was 42 times higher than that obtained with the anthraquinone dye Reactive Blue 4. The effect of RM on dye reduction was more evident for azo dyes resistant to reductive processes, and ineffective for anthraquinone dyes because of the structural stability of the latter.

  20. Effects of dissolved organic matters (DOMs) on membrane fouling in anaerobic ceramic membrane bioreactors (AnCMBRs) treating domestic wastewater.

    Science.gov (United States)

    Yue, Xiaodi; Koh, Yoong Keat Kelvin; Ng, How Yong

    2015-12-01

    Anaerobic membrane bioreactors (AnMBRs) have been regarded as a potential solution to achieve energy neutrality in the future wastewater treatment plants. Coupling ceramic membranes into AnMBRs offers great potential as ceramic membranes are resistant to corrosive chemicals such as cleaning reagents and harsh environmental conditions such as high temperature. In this study, ceramic membranes with pore sizes of 80, 200 and 300 nm were individually mounted in three anaerobic ceramic membrane bioreactors (AnCMBRs) treating real domestic wastewater to examine the treatment efficiencies and to elucidate the effects of dissolved organic matters (DOMs) on fouling behaviours. The average overall chemical oxygen demands (COD) removal efficiencies could reach around 86-88%. Although CH4 productions were around 0.3 L/g CODutilised, about 67% of CH4 generated was dissolved in the liquid phase and lost in the permeate. When filtering mixed liquor of similar properties, smaller pore-sized membranes fouled slower in long-term operations due to lower occurrence of pore blockages. However, total organic removal efficiencies could not explain the fouling behaviours. Liquid chromatography-organic carbon detection, fluorescence spectrophotometer and high performance liquid chromatography coupled with fluorescence and ultra-violet detectors were used to analyse the DOMs in detail. The major foulants were identified to be biopolymers that were produced in microbial activities. One of the main components of biopolymers--proteins--led to different fouling behaviours. It is postulated that the proteins could pass through porous cake layers to create pore blockages in membranes. Hence, concentrations of the DOMs in the soluble fraction of mixed liquor (SML) could not predict membrane fouling because different components in the DOMs might have different interactions with membranes.

  1. Anaerobic digestion of industrial hemp-effect of harvest time on methane energy yield per hectare

    Energy Technology Data Exchange (ETDEWEB)

    Kreuger, E.; Escobar, F.; Bjoernsson, L. [Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Prade, T.; Svensson, S.-E.; Englund, J.-E. [Department of Agriculture-Farming Systems, Technology and Product Quality, Swedish University of Agricultural Sciences, P.O. Box 104, SE-230 53 Alnarp (Sweden)

    2011-02-15

    There is a worldwide emphasis to increase the share of renewable transportation fuels. When using agricultural land for production of renewable transportation fuels, the energy output per hectare for different crops and transportation fuels is a crucial factor. In this study, the gross methane energy yield per hectare from anaerobic digestion of industrial hemp (Cannabis sativa L.), was determined at four different harvest times between July and October in Southern Sweden, a cold climate region. The biomass yield was determined for three years and the methane yield was determined for two years through the biochemical methane potential test. The highest biomass yield, 16 tonnes dry matter per hectare on an average, and the highest methane energy yield per hectare was achieved when the hemp was harvested in September or October, with an average gross methane energy yield of 136 {+-} 24 GJ per hectare. There was no significant difference in the specific methane yield between the harvest times; the average being 234 {+-} 35 m{sup 3} per tonne volatile solids. Biogas from hemp turned out to be a high yielding alternative to the currently dominating renewable transportation fuels produced from crops grown in Sweden: ethanol from wheat and biodiesel from rapeseed. (author)

  2. Start-up of the SHARON and ANAMMOX process in landfill bioreactors using aerobic and anaerobic ammonium oxidising biomass.

    Science.gov (United States)

    Shalini, S Sri; Joseph, Kurian

    2013-12-01

    The main aim of this study is to analyse the feasibility to use aerobic ammonium oxidising bacteria (AOB) and anammox/AnAOB biomass enriched from mined municipal solid waste for in situ SHARON and ANAMMOX processes in laboratory scale landfill bioreactors (LFBR) for ammonia nitrogen removal. For this purpose, three LFBRs were operated as Control (without biomass seed), SHARON (with AOB biomass seed) and ANAMMOX (with anammox biomass seed) for 315 days. Results showed nitrogen loading rate of 1.0 kg N/d was effectively removed in SHARON and ANAMMOX LFBR. In SHARON LFBR, partial nitritation efficiency reached up to 98.5% with AOB population of MPN of 5.1 × 10(6)/mL obtained. ANAMMOX LFBR gave evolution of 95% of nitrogen gas as the end product confirmed the ANAMMOX process. Nitrogen transformations, biomass development and hydrazine and hydroxylamine formation authenticated the enriched AOB and anammox biomass activity in landfill bioreactors.

  3. Biological nutrients removal from the supernatant originating from the anaerobic digestion of the organic fraction of municipal solid waste.

    Science.gov (United States)

    Malamis, S; Katsou, E; Di Fabio, S; Bolzonella, D; Fatone, F

    2014-09-01

    phosphorus from the anaerobic supernatant of OFMSW is an interesting research topic that has not yet been explored. At the moment, standardization in the design of facilities that treat anaerobic supernatant produced from the treatment of OFMSW is still under development. To move toward this direction, it is first necessary to assess the performance of alternative treatment options. It study concentrates existing data regarding the characteristics of the anaerobic supernatant produced from the treatment of OFMSW and from their co-digestion with other BOW. This provides data documenting the effect of the anaerobic digestion operating conditions on the supernatant quality and critically evaluates alternative options for the post-treatment of the liquid fraction produced from the anaerobic digestion process.

  4. Effects of titanium dioxide and zinc oxide nanoparticles on methane production from anaerobic co-digestion of primary and excess sludge.

    Science.gov (United States)

    Zheng, Xiong; Wu, Lijuan; Chen, Yinguang; Su, Yinglong; Wan, Rui; Liu, Kun; Huang, Haining

    2015-01-01

    Anaerobic co-digestion of primary and excess sludge is regarded as an efficient way to reuse sludge organic matter to produce methane. In this study, short-term and long-term exposure experiments were conducted to investigate the possible effects of titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles (NPs) on methane production from anaerobic co-digestion of primary and excess sludge. The data showed that TiO2 NPs had no measurable impact on methane production, even at a high concentration (150 mg/g total suspended solids (TSS)). However, short-term (8 days) exposure to 30 or 150 mg/g-TSS of ZnO NPs significantly decreased methane production. More importantly, these negative effects of ZnO NPs on anaerobic sludge co-digestion were not alleviated by increasing the adaptation time to 105 days. Further studies indicated that the presence of ZnO NPs substantially decreased the abundance of methanogenic archaea, which reduced methane production. Meanwhile, the activities of some key enzymes involved in methane production, such as protease, acetate kinase, and coenzyme F420, were remarkably inhibited by the presence of ZnO NPs, which was also an important reason for the decreased methane production. These results provide a better understanding of the potential risks of TiO2 and ZnO NPs to methane production from anaerobic sludge co-digestion.

  5. Application of real-time PCR to determination of combined effect of antibiotics on Bacteria, Methanogenic Archaea, Archaea in anaerobic sequencing batch reactors.

    Science.gov (United States)

    Aydin, Sevcan; Ince, Bahar; Ince, Orhan

    2015-06-01

    This study evaluated the long-term effects of erythromycin-tetracycline-sulfamethoxazole (ETS) and sulfamethoxazole-tetracycline (ST) antibiotic combinations on the microbial community and examined the ways in which these antimicrobials impact the performance of anaerobic reactors. Quantitative real-time PCR was used to determine the effect that different antibiotic combinations had on the total and active Bacteria, Archae and Methanogenic Archae. Three primer sets that targeted metabolic genes encoding formylterahydrofolate synthetase, methyl-coenzyme M reductase and acetyl-coA synthetase were also used to determine the inhibition level on the mRNA expression of the homoacetogens, methanogens and specifically acetoclastic methanogens, respectively. These microorganisms play a vital role in the anaerobic degradation of organic waste and targeting these gene expressions offers operators or someone at a treatment plant the potential to control and the improve the anaerobic system. The results of the investigation revealed that acetogens have a competitive advantage over Archaea in the presence of ETS and ST combinations. Although the efficiency with which methane production takes place and the quantification of microbial populations in both the ETS and ST reactors decreased as antibiotic concentrations increased, the ETS batch reactor performed better than the ST batch reactor. According to the expression of genes results, the syntrophic interaction of acetogens and methanogens is critical to the performance of the ETS and ST reactors. Failure to maintain the stability of these microorganisms resulted in a decrease in the performance and stability of the anaerobic reactors.

  6. Influence of fluid dynamics on anaerobic digestion of food waste for biogas production.

    Science.gov (United States)

    Wang, Fengping; Zhang, Cunsheng; Huo, Shuhao

    2016-08-17

    To enhance the stability and efficiency of an anaerobic process, the influences of fluid dynamics on the performance of anaerobic digestion and sludge granulation were investigated using computational fluid dynamics (CFD). Four different propeller speeds (20, 60, 100, 140 r/min) were adopted for anaerobic digestion of food waste in a 30 L continuously stirred tank reactor (CSTR). Experimental results indicated that the methane yield increased with increasing the propeller speed within the experimental range. Results from CFD simulation and sludge granulation showed that the optimum propeller speed for anaerobic digestion was 100 r/min. Lower propeller speed (20 r/min) inhibited mass transfer and resulted in the failure of anaerobic digestion, while higher propeller speed (140 r/min) would lead to higher energy loss and system instability. Under this condition, anaerobic digestion could work effectively with higher efficiency of mass transfer which facilitated sludge granulation and biogas production. The corresponding mean liquid velocity and shear strain rate were 0.082 m/s and 10.48 s(-1), respectively. Moreover, compact granular sludge could be formed, with lower energy consumption. CFD was successfully used to study the influence of fluid dynamics on the anaerobic digestion process. The key parameters of the optimum mixing condition for anaerobic digestion of food waste in a 30 L CSTR including liquid velocity and shear strain rate were obtained using CFD, which were of paramount significance for the scale-up of the bioreactor. This study provided a new way for the optimization and scale-up of the anaerobic digestion process in CSTR based on the fluid dynamics analysis.

  7. Metabolic interactions between methanogenic consortia and anaerobic respiring bacteria

    DEFF Research Database (Denmark)

    Stams, A.J.; Oude Elferink, S.J.; Westermann, Peter

    2003-01-01

    Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic respiring bacteria are toxic to methanogenic...... consortia. Despite the potentially adverse effects, only few inorganic electron acceptors potentially utilizable for anaerobic respiration have been investigated with respect to negative interactions in anaerobic digesters. In this chapter we review competitive and inhibitory interactions between anaerobic...... respiring populations and methanogenic consortia in bioreactors. Due to the few studies in anaerobic digesters, many of our discussions are based upon studies of defined cultures or natural ecosystems...

  8. Thermal hydrolysis integration in the anaerobic digestion process of different solid wastes: energy and economic feasibility study.

    Science.gov (United States)

    Cano, R; Nielfa, A; Fdz-Polanco, M

    2014-09-01

    An economic assessment of thermal hydrolysis as a pretreatment to anaerobic digestion has been achieved to evaluate its implementation in full-scale plants. Six different solid wastes have been studied, among them municipal solid waste (MSW). Thermal hydrolysis has been tested with batch lab-scale tests, from which an energy and economic assessment of three scenarios is performed: with and without energy integration (recovering heat to produce steam in a cogeneration plant), finally including the digestate management costs. Thermal hydrolysis has lead to an increase of the methane productions (up to 50%) and kinetics parameters (even double). The study has determined that a proper energy integration design could lead to important economic savings (5 €/t) and thermal hydrolysis can enhance up to 40% the incomes of the digestion plant, even doubling them when digestate management costs are considered. In a full-scale MSW treatment plant (30,000 t/year), thermal hydrolysis would provide almost 0.5 M€/year net benefits.

  9. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    NARCIS (Netherlands)

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become m

  10. 分级分相厌氧消化工艺在污泥处理中的应用%The Practical Feasibility of Hierarchical Split-phase Anaerobic Digestion Process in Dludge Treatment

    Institute of Scientific and Technical Information of China (English)

    邵自江

    2013-01-01

    Based on the analysis of the principle and development trend of anaerobic digestion process, this paper raises the hierarchical split-phase anaerobic digestion process, and analyses the process and advantages of it. The classification phase anaerobic digestion process has obvious advantages on stability, impact resistant ability and regional coordination treatment of organic solid waste. The sludge treatment process more relevant country strategy. Combining with the current urgent task of urban sludge treatment and disposal in our country, this paper holds that urban sludge anaerobic digestion process should focus on the choice of hierarchical split-phase anaerobic digestion process.%通过对厌氧消化工艺的原理、发展趋势分析,引出了分级分相厌氧消化工艺;并对此工艺的流程及特点进行剖析。分级分相厌氧消化工艺在运行稳定性、抗冲击能力、区域有机固体废物协同处理和切合国家污泥处理战略上均具有明显优势。结合当前我国城市污泥处理、处置的现状,认为,在城市污泥厌氧消化处理时应重点考虑分级分相厌氧消化工艺。

  11. Temperature effects on the trophic stages of perennial rye grass anaerobic digestion.

    Science.gov (United States)

    Cysneiros, D; Thuillier, A; Villemont, R; Littlestone, A; Mahony, T; O'Flaherty, V

    2011-01-01

    Continuous Stirred Tank Reactors (CSTRs), operated in batch mode, were used to evaluate the feasibility of psychrophilic (low temperature) digestion of perennial rye grass in a long term experiment (150 days) for the first time. The reactors were operated in parallel at 3 different temperatures, 10, 15 and 37 degrees C. Hydrolysis, acidification and methanogenesis were assessed by VS degradation, by soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFA) production, and by methane production, respectively. Hydrolysis was the rate-limiting step at all temperatures and the rates and extent of hydrolysis were considerably lower at 15 and 10 degrees C, than at 37 degrees C. The total VS degradation was 53%, 34% and 19% at 37, 15 and 10 degrees C, respectively. Acidification was not affected by temperature and VFA production and consumption was balanced in all cases, except at 10 degrees C. Methane yields were 0.215 m3 CH4 kg(-1) VS(-1) added, 0.160 m3 CH4 kg(-1) VS(-1) added and 0.125 m3 CH4 kg(-1) VS(-1) added at 37, 15 and 10 degrees C, respectively. Methanogenesis was not strongly affected at 15 C but it became rate-limiting at 10 degrees C. Overall, the solid degradation and methane production performance under psychrophilic conditions was encouraging and greater than previously reported. Considering the non-acclimated, mesophilic nature of the inoculum, there are grounds to believe that low-temperature anaerobic digestion of grass could be feasible if coupled to efficient hydrolysis of the biomass.

  12. Prospects of Anaerobic Digestion Technology in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As the world's largest developing country, China must face the problem of managing municipal solid waste, and the challenge of organic waste disposal is even more serious. Considering the characteristics of traditional waste disposal technologies and the subsequent secondary pollution, anaerobic digestion has various advantages such as reduction in the land needed for disposal and preservation of environmental quality. In light of the energy crisis, this paper focuses on the potential production of biogas from biowaste through anaerobic digestion processes, the problems incurred by the waste collection system, and the efficiency of the anaerobic digestion process. Use of biogas in a combined heat and power cogeneration system is also discussed. Finally, the advantages of anaerobic digestion technology for the Chinese market are summarized. The anaerobic digestion is suggested to be a promising treating technology for the organic wastes in China.

  13. Toxicants inhibiting anaerobic digestion: a review.

    Science.gov (United States)

    Chen, Jian Lin; Ortiz, Raphael; Steele, Terry W J; Stuckey, David C

    2014-12-01

    Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.

  14. Effects of influent fractionation, kinetics, stoichiometry and mass transfer on CH4, H2 and CO2 production for (plant-wide) modeling of anaerobic digesters.

    Science.gov (United States)

    Solon, Kimberly; Flores-Alsina, Xavier; Gernaey, Krist V; Jeppsson, Ulf

    2015-01-01

    This paper examines the importance of influent fractionation, kinetic, stoichiometric and mass transfer parameter uncertainties when modeling biogas production in wastewater treatment plants. The anaerobic digestion model no. 1 implemented in the plant-wide context provided by the benchmark simulation model no. 2 is used to quantify the generation of CH₄, H₂and CO₂. A comprehensive global sensitivity analysis based on (i) standardized regression coefficients (SRC) and (ii) Morris' screening's (MS's) elementary effects reveals the set of parameters that influence the biogas production uncertainty the most. This analysis is repeated for (i) different temperature regimes and (ii) different solids retention times (SRTs) in the anaerobic digester. Results show that both SRC and MS are good measures of sensitivity unless the anaerobic digester is operating at low SRT and mesophilic conditions. In the latter situation, and due to the intrinsic nonlinearities of the system, SRC fails in decomposing the variance of the model predictions (R² < 0.7) making MS a more reliable method. At high SRT, influent fractionations are the most influential parameters for predictions of CH₄and CO₂emissions. Nevertheless, when the anaerobic digester volume is decreased (for the same load), the role of acetate degraders gains more importance under mesophilic conditions, while lipids and fatty acid metabolism is more influential under thermophilic conditions. The paper ends with a critical discussion of the results and their implications during model calibration and validation exercises.

  15. Solid anaerobic digestion batch of bio-waste as pre-treatment for improving amendment quality: The effect of inoculum recirculation.

    Science.gov (United States)

    Di Maria, Francesco; Segoloni, Enrico; Pezzolla, Daniela

    2016-10-01

    The effect of solid anaerobic digestion batch (SADB) on bio-waste performed with and without inoculum on the quality of the final amendment was investigated by means of determining the content of organic carbon, humic and fulvic acids and the degree of humification. Two different processes were compared: composting and SADB with post-composting. Six parallel tests were performed. In three of these tests the SADB was inoculated mixing the bio-waste with the digestate from the previous run in a 1:1 ratio by weight. The amendment obtained by the SADB with post-composting treatment, in which the SADB was not inoculated, had an organic carbon content ranging from 15.5% TS to 30.3% TS resulting from 1% up to 14% higher than that of the corresponding composting processes. Similar results were achieved for the degree of humification. On the other hand SADB in which the inoculum was used generated about 300NL/kgVS of biogas instead of about 267NL/kgVS for non-inoculated runs.

  16. Anaerobic mesophilic co-digestion of ensiled sorghum, cheese whey and liquid cow manure in a two-stage CSTR system: Effect of hydraulic retention time.

    Science.gov (United States)

    Dareioti, Margarita Andreas; Kornaros, Michael

    2015-01-01

    The aim of this study was to investigate the effect of hydraulic retention time (HRT) on hydrogen and methane production using a two-stage anaerobic process. Two continuously stirred tank reactors (CSTRs) were used under mesophilic conditions (37°C) in order to enhance acidogenesis and methanogenesis. A mixture of pretreated ensiled sorghum, cheese whey and liquid cow manure (55:40:5, v/v/v) was used. The acidogenic reactor was operated at six different HRTs of 5, 3, 2, 1, 0.75 and 0.5d, under controlled pH5.5, whereas the methanogenic reactor was operated at three HRTs of 24, 16 and 12d. The maximum H2 productivity (2.14L/LRd) and maximum H2 yield (0.70mol H2/mol carbohydrates consumed) were observed at 0.5d HRT. On the other hand, the maximum CH4 production rate of 0.90L/LRd was achieved at HRT of 16d, whereas at lower HRT the process appeared to be inhibited and/or overloaded.

  17. Anaerobic degradation and toxicity of commercial cationic surfactants in anaerobic screening tests.

    Science.gov (United States)

    García, M T; Campos, E; Sánchez-Leal, J; Ribosa, I

    2000-09-01

    Anaerobic biodegradability and toxicity on anaerobic bacteria of di(hydrogenated tallow) dimethyl ammonium chloride (DHTDMAC) and two esterquats have been investigated. A batch test system containing municipal digester solids as a source of anaerobic bacteria, based on the method proposed by the ECETOC, has been applied. To evaluate the potential toxicity of such surfactants on anaerobic sludge, a co-substrate, an easily biodegradable compound in anaerobic conditions, has been added to the samples to test and the effects on biogas production have been determined. For the esterquats studied high biodegradation levels were obtained and no toxic effects on anaerobic bacteria were observed even at the highest concentrations tested, 100 and 200 mg C/l, respectively. On the contrary, DHTDMAC was not degradated at the same test conditions. However, no inhibitory effects on the biogas production were detected for this surfactant at concentrations <100 mg C/l.

  18. Anaerobic methanethiol degradation and methanogenic community analysis in an alkaline (pH 10) biological process for liquefied petroleum gas desulfurization

    NARCIS (Netherlands)

    Leerdam, van R.C.; Bonilla-Salinas, M.; Bok, de F.A.M.; Bruning, H.; Lens, P.N.L.; Stams, A.J.M.; Janssen, A.J.H.

    2008-01-01

    Anaerobic methanethiol (MT) degradation by mesophilic (30 degrees C) alkaliphilic (pH 10) communities was studied in a lab-scale Upflow Anaerobic Sludge Bed (UASB) reactor inoculated with a mixture of sediments from the Wadden Sea (The Netherlands), Soap Lake (Central Washington), and Russian soda l

  19. The Buoyant Filter Bioreactor: a high-rate anaerobic reactor for complex wastewater--process dynamics with dairy effluent.

    Science.gov (United States)

    Haridas, Ajit; Suresh, S; Chitra, K R; Manilal, V B

    2005-03-01

    A novel high-rate anaerobic reactor, called "Buoyant Filter Bioreactor" (BFBR), has been developed for treating lipid-rich complex wastewater. The BFBR is able to decouple the biomass and insoluble COD retention time from the hydraulic retention time by means of a granular filter bed made of buoyant polystyrene beads. Filter clogging is prevented by an automatic backwash driven by biogas release, which fluidizes the granular filter bed in a downward direction. During filter backwash, the solids captured in the filter are reintroduced into the reaction zone of the reactor. The reaction zone is provided with a mixing system, which is independent of the hydraulic retention time. The performance of a laboratory-scale BFBR was studied for the treatment of dairy effluent, chosen as a model complex wastewater. The dairy effluent was not pre-treated for fat removal. The BFBR was operated over 400 d and showed greater than 85% COD removal at 10 kg COD/(m3/d). The COD conversion to methane in the BFBR was essentially complete. The BFBR performance improved with age, and with feed containing 3200 mg COD/l, the treated effluent had 120 mg COD/l and no turbidity. The hold-up of degradable biosolids, including scum, inside the BFBR was estimated using starvation tests. When load is increased, scum accumulates inside the BFBR and then decays after undergoing change from hydrophobic to hydrophilic. This is explained as the accumulation of fat solids, its conversion to insoluble long chain fatty acids and its further solubilization and degradation.

  20. Energy from anaerobic methane production. [Sweden

    Energy Technology Data Exchange (ETDEWEB)

    1982-02-01

    Since 1970 Swedish researchers have been testing the ANAMET (anaerobic-aerobic-methane) process, which involves converting industrial wastewaters via an initial anaerobic microbiological step followed by an aerobic one. Recycling the biomass material in each step allows shorter hydraulic retention times without decreasing stability or solids reduction. Since the first ANAMET plants began operating at a Swedish sugar factory in 1972, 17 more plants have started up or are under construction. Moreover, the ANAMET process has engendered to offshoot BIOMET (biomass-methane) process, a thermophilic anaerobic scheme that can handle sugar-beet pulp as well as grass and other soft, fast-growing biomasses.