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Sample records for anaerobic digestion process

  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. 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.

  3. 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.

  4. 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…

  5. 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....

  6. 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...

  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. 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...

  9. 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.)

  10. 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.

  11. 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.

  12. 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...

  13. 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

  14. 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

  15. 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…

  16. 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.

  17. 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...

  18. 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

  19. 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

  20. 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.

  1. 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...

  2. 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...

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. [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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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...

  15. 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...

  16. 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

  17. [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.

  18. 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).

  19. [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.

  20. 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)).

  1. 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.

  2. 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...

  3. 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...

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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).

  9. 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.

  10. 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.

  11. 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...

  12. 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.

  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. 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.

  15. 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.

  16. 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.

  17. Anaerobic digestion of solid material

    DEFF Research Database (Denmark)

    Vavilin, V.A.; Lokshina, L.Y.; Flotats, X.

    2007-01-01

    A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non-uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous-flow anaerobic digestion. Batch experiments reported and simulate...

  18. 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.

  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

    Anaerobic digestion is a multi-beneficial biological treatment during which micro-organisms degrade organic material producing biogas (i.e. methane) and stabilised end-product (i.e. digestate). Methane is a versatile renewable energy source and digestate can be used as an organic fertiliser and/or soil improver. Because of the increasing consumption and tightening environment and health legislation, production of organic wastes suitable for anaerobic digestion increases. Animal by-products (ABP) from the meat-processing industry are often rendered (contaminated material), used as feedstock (in fur breeding), or composted. However, ABPs studied could not be utilised in fodder or in animal food production and have currently been rendered or directed to composting, despite being mostly considered unsuitable for composting. Many ABPs are energy-rich, wet and pasty materials and suitable for the anaerobic digestion process. Moreover, suitable pre-treatment to hydrolyse solid materials and/or co-digestion of two or several materials may improve the anaerobic digestion with ultimate goal to increase the methane production, stabilisation and reusability of digestate. The case chosen for more detailed research was that of a middle-sized Finnish meat-processing industry. The aim of the thesis was to evaluate the feasibility of different ABPs presently available for treatment as raw material for anaerobic digestion. Another objective was to enhance the anaerobic digestion process via specific pre-treatments and co-digestion cases with the ultimate aim to increase the methane production and the quality of the digestate. The general goal was to observe the overall process from the perspective of real-circumstances in Finland to rise to needs in practice and to produce exploitable information for adopting sustainable development locally and case-specifically into practice via versatile anaerobic digestion technology. The ABPs studied were highly bio-degradable and especially

  20. 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.

  1. 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.

  2. Anaerobic digestion foaming causes – A review

    OpenAIRE

    Ganidi, Nafsika; Tyrrel, Sean F.; Cartmell, Elise

    2009-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water companies due to significant impacts on process efficiency and operational costs. Several foaming causes have been identified over the past few years by researchers. However, the supporting experimental information is limited and in some cases absent. The present report aims to provide a detailed review of the current anaerobic digestion foaming proble...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  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. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær;

    2001-01-01

    The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern...... requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader...

  13. Multivariate monitoring of anaerobic co-digestion

    DEFF Research Database (Denmark)

    Madsen, Michael; Holm-Nielsen, Jens Bo

    Anaerobic digestion processes for production of renewable energy in the form of biogas, and in the future hydrogen, are becoming increasingly important worldwide. Sustainable solutions for renewable energy production systems are given high political priority, amongst other things due to global...... warming and environmental concerns. Anaerobic digestion applied in agriculture can simultaneously convert heterogeneous biomasses and wastes from the primary agricultural sector and from the bio processing industries, for instance food processing, pharma, and biofuel production, into valuable organic...... fertiliser and renewable energy. Meanwhile, in order for the biogas sector to become a significant player in the energy supply chain, the anaerobic digestion process has to be controlled to a greater extent than what is implemented as state-of-the-art today. Through application of the philosophy behind...

  14. 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).

  15. 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)

  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. 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.

  18. 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.

  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. 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.

  1. Anaerobic hydrolysis during digestion of complex substrates

    NARCIS (Netherlands)

    Sanders, W.T.M.

    2001-01-01

    Complex waste(water) such as, raw sewage, dairy wastewater, slaughterhouse wastewater, fish processing wastewater, primary sludge and the organic fraction of municipal solid waste have been proven to be degradable under anaerobic conditions. However, during the digestion process the conversion of th

  2. 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.

  3. 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).

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. Anaerobic Digestion in a Flooded Densified Leachbed

    Science.gov (United States)

    Chynoweth, David P.; Teixeira, Arthur A.; Owens, John M.; Haley, Patrick J.

    2009-01-01

    A document discusses the adaptation of a patented biomass-digesting process, denoted sequential batch anaerobic composting (SEBAC), to recycling of wastes aboard a spacecraft. In SEBAC, high-solids-content biomass wastes are converted into methane, carbon dioxide, and compost.

  9. A fuzzy logic approach to control anaerobic digestion

    NARCIS (Netherlands)

    Domnanovich, A.M.; Strik, D.P.B.T.B.; Pfeiffer, B.; Karlovits, M.; Zani, L.; Braun, R.; Holubar, P.

    2003-01-01

    One of the goals of the EU-Project AMONCO (Advanced Prediction, Monitoring and Controlling of Anaerobic Digestion Process Behaviour towards Biogas Usage in Fuel Cells) is to create a control tool for the anaerobic digestion process, which predicts the volumetric organic loading rate (Bv) for the nex

  10. Balancing hygienization and anaerobic digestion of raw sewage sludge.

    Science.gov (United States)

    Astals, S; Venegas, C; Peces, M; Jofre, J; Lucena, F; Mata-Alvarez, J

    2012-12-01

    The anaerobic digestion of raw sewage sludge was evaluated in terms of process efficiency and sludge hygienization. Four different scenarios were analyzed, i.e. mesophilic anaerobic digestion, thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a 60 °C or by an 80 °C hygienization treatment. Digester performance (organic matter removal, process stability and biogas yield) and the hygienization efficiency (reduction of Escherichia coli, somatic coliphages and F-specific RNA phages) were the main examined factors. Moreover, a preliminary economical feasibility study of each option was carried out throughout an energy balance (heat and electricity). The obtained results showed that both thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a hygienization step were able to produce an effluent sludge that fulfills the American and the European legislation for land application. However, higher removal efficiencies of indicators were obtained when a hygienization post-treatment was present. Regarding the energy balance, it should be noted that all scenarios have a significant energy surplus. Particularly, positive heat balances will be obtained for the thermophilic anaerobic digestion and for the mesophilic anaerobic digestion followed by 60 °C hygienization post-treatment if an additional fresh-sludge/digested sludge heat exchanger is installed for energy recovery.

  11. 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)

  12. 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.

  13. 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.

  14. 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...

  15. 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...

  16. 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...

  17. 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)

  18. Anaerobic Digestion Modeling: from One to Several Bacterial Populations

    Directory of Open Access Journals (Sweden)

    Iván D. Ramírez-Rivas

    2013-11-01

    Full Text Available Anaerobic digestion systems are complex processes that unfortunately often suffer from instability causing digester failure. In order to be able to design, optimizing and operate efficiently anaerobic digestion systems, appropriate control strategies need to be designed. Such strategies require, in general, the development of mathematical models. The anaerobic digestion process comprises a complex network of sequential and parallel reactions of biochemical and physicochemical nature. Usually, such reactions contain a particular step, the so called rate-limiting step which, being the slowest, limits the reaction rate of the overall process. The first attempts for modeling anaerobic digestion led to models describing only the limiting step. However, over a wide range of operating conditions, the limiting step is not always the same. It may depend on wastewater characteristics, hydraulic loading, temperature, etc. It is apparent that the "limiting step hypothesis" leads to simple and readily usable models. Such models, however, do not describe very well the digester behavior, especially under transient operating conditions. This work reviews the current state-of-the-art in anaerobic digestion modeling. We give a brief description of the key anaerobic digestion models that have been developed so far for describing biomass growth systems, including the International Water Association’s Anaerobic Digestion Model 1 (ADM1 and we identify the areas that require further research endeavors.

  19. 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.

  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. Anaerobic co-digestion of organic wastes

    OpenAIRE

    2009-01-01

    Tese de doutoramento em Engenharia Química e Biológica Anaerobic digestion is an already established process but the increasing need of bio‐waste recovery has determined the emergence of new substrates, revamping the research in this field. Contrary to some other European countries, in Portugal this technology is still scarcely in use. Nonetheless, the current legislation endorses this application as a waste management and as an energy recovery process. The rapid growth of the ...

  2. 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.

  3. Horse manure as feedstock for anaerobic digestion.

    Science.gov (United States)

    Hadin, Sa; Eriksson, Ola

    2016-10-01

    Horse keeping is of great economic, social and environmental benefit for society, but causes environmental impacts throughout the whole chain from feed production to manure treatment. According to national statistics, the number of horses in Sweden is continually increasing and is currently approximately 360,000. This in turn leads to increasing amounts of horse manure that have to be managed and treated. Current practices could cause local and global environmental impacts due to poor performance or lack of proper management. Horse manure with its content of nutrients and organic material can however contribute to fertilisation of arable land and recovery of renewable energy following anaerobic digestion. At present anaerobic digestion of horse manure is not a common treatment. In this paper the potential for producing biogas and biofertiliser from horse manure is analysed based on a thorough literature review in combination with mathematical modelling and simulations. Anaerobic digestion was chosen as it has a high degree of resource conservation, both in terms of energy (biogas) and nutrients (digestate). Important factors regarding manure characteristics and operating factors in the biogas plant are identified. Two crucial factors are the type and amount of bedding material used, which has strong implications for feedstock characteristics, and the type of digestion method applied (dry or wet process). Straw and waste paper are identified as the best materials in an energy point of view. While the specific methane yield decreases with a high amount of bedding, the bedding material still makes a positive contribution to the energy balance. Thermophilic digestion increases the methane generation rate and yield, compared with mesophilic digestion, but the total effect is negligible.

  4. 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.

  5. Foaming phenomenon in bench-scale anaerobic digesters.

    Science.gov (United States)

    Siebels, Amanda M; Long, Sharon C

    2013-04-01

    The Madison Metropolitan Sewerage District (The District) in Madison, Wisconsin has been experiencing seasonal foaming in their anaerobic biosolids digesters, which has occurred from mid-November to late June for the past few years. The exact cause(s) of foaming is unknown. Previous research findings are unclear as to whether applications of advanced anaerobic digestion processes reduce the foaming potential of digesters. The object of this study was to investigate how configurations of thermophilic and acid phase-thermophilic anaerobic digestion would affect foaming at the bench-scale level compared to single stage mesophilic digestion for The District. Bench-scale anaerobic digesters were fed with a 4 to 4.5% by dry weight of solids content blend of waste activated sludge (WAS) and primary sludge from The District. Foaming potential was monitored using Alka-Seltzer and aeration foaming tests. The bench-scale acid phase-thermophilic digester had a higher foaming potential than the bench-scale mesophilic digester. These results indicate that higher temperatures increase the foaming potential of the bench-scale anaerobic digesters. The bench-scale acid phase-thermophilic digesters had a greater percent (approximately 5 to 10%) volatile solids destruction and a greater percent (approximately 5 to 10%) total solids destruction when compared to the bench-scale mesophilic digester. Overall, for the full-scale foaming experienced by The District, it appears that adding an acid phase or switching to thermophilic digestion would not alleviate The District's foaming issues.

  6. 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.

  7. 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)

  8. Anaerobic digestion and co-digestion of slaughterhouse wastes

    Directory of Open Access Journals (Sweden)

    Sonia Castellucci

    2013-09-01

    Full Text Available The use of renewable energy is becoming increasingly necessary in order to address the global warming problem and, as a consequence, has become an high priority for many countries. Biomass is a clean and renewable energy source with growing potential to replace conventional fossil fuels. Among biomass, residual and waste ones represent a great resource for energy generation since they permit both to eliminate a possible waste and to produce energy. In the present work, the case of slaughterhouse wastes (SHWs has been investigated. Anaerobic digestion is nowadays considered as one of the most important and sustainable conversion technology exploiting organic matter and biodegradable wastes. Biogas results from this bio-chemical process and mainly consists of methane and carbon dioxide, leading to produce thermal energy and/or electricity. In this paper, the European Regulations on animal by-products (ABPs are described, and some previous study on anaerobic digestion and co-digestion of ABPs - more precisely SHWs - are considered and compared in order to fix a starting point for future tests on their co-digestion in a micro-scale pilot digester. This is to define optimal feed ratio values which ensure an increasing content of methane in the outgoing biogas.

  9. INCREASING ANAEROBIC DIGESTION PERFORMANCE OF WASTEWATER WITH CO-DIGESTION USING DECANTER CAKE

    Directory of Open Access Journals (Sweden)

    Thaniya Kaosol

    2014-01-01

    Full Text Available 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 potential of different HRTs and that of wastewater digestion alone. The anaerobic co-digestion is operated in continuous with continuously stirred reactors at HRT of 10, 20 and 30 days. The mechanical stirring units of all reactors are operated automatically. The stirring action occurred continuously during the experiments. The anaerobic co-digestion results show that the anaerobic co-digestion provides higher biogas production rate and higher methane yield than that of the wastewater digestion alone. The optimum HRT of the anaerobic co-digestion is 20 days. This reactor produces 2.88 L day-1, with 64.5% of methane and the maximum methane production rate of 1.87 L day-1 and the methane yield of 0.321 l CH4/g CODremoved. The anaerobic co-digestion of wastewater with decanter cake provides the higher methane yield potential production than that provided by the wastewater digestion alone at the ambient temperature. The best HRT is 20 days for anaerobic co-digestion between the wastewater and decanter cake. The experimental results reveal that HRT and co-digestion are the parameters that can affect the biogas production and methane yield.

  10. 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)

  11. 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.

  12. 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.

  13. Tar water digestion in an upflow anaerobic sludge blanket reactor

    Energy Technology Data Exchange (ETDEWEB)

    Skibsted Mogensen, A.; Angelidaki, I.; Schmidt, J.E.; Ahring, B.K. [Technical Univ., Dept. of Environmental Science and Engineering, Lyngby (Denmark)

    1998-08-01

    The water from the gasification and wet oxidised tar water has been digested anaerobically in UASB reactors and were digested in respectively 10 and 50% in batches. Though the tar water show inhibition at very low concentrations to aerobic microorganisms, the granular sludge used in UASB reactors degrades tar water in concentrations that reveal total inhibition of e.g. bacteria conducting the nitrification process. The value of waste waters are determined, showing that the tar water produces more biogas in the anaerobic digestion. A wide range of xenobiotics, especially phenolic compounds can be transformed in the anaerobic digestion process. Seven phenolic are followed in batch experiments and UASB reactor experiments, and their particular fate in the anaerobic systems embody large differences in the transformation pattern. (au) 24 refs.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. Environmental impacts of anaerobic digestion and the use of anaerobic residues as soil amendment

    Energy Technology Data Exchange (ETDEWEB)

    Mosey, F.E. [VFA Services Ltd., Herts (United Kingdom)

    1996-01-01

    This paper defines the environmental role of anaerobic digestion within the overall objective of recovering energy from renewable biomass resources. Examples and opportunities for incorporating anaerobic digestion into biomass-to-energy schemes are discussed, together with environmental aspects of anaerobic digestion plants. These include visual, public amenity, pathogens and public health, odor control, and gaseous emissions. Digestate disposal and the benefits of restrictions on recycling organic wastes and biomass residues back to the land are discussed, particularly as they relate to American and European codes of practice and environmental legislation. The paper concludes that anaerobic digestion, if performed in purpose-designed reactors that efficiently recover and use biogas, is an environmentally benign process that can enhance energy recovery and aid the beneficial land use of plant residues in many biomass-to-energy schemes.

  19. Modeling flow inside an anaerobic digester by CFD techniques

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza, Alexandra Martinez; Jimenez, P. Amparo Lopez [Departmento do Ingenieria Hidralica y Medio Ambiente, Universitat Politecnica de Valencia, Camino de Vera S/N 46022 (Spain); Martinez, Tatiana Montoya; Monanana, Vincente Fajardo [Grupo Aquas de Valencia. Avenida Marques del Turia 19 46005 Valencia (Spain)

    2011-07-01

    Anaerobic processes are used to treat high strength organic wastewater as well as for the treatment of primary and secondary sludge from conventional wastewater treatment plants. In these processes, heterotrophic microorganisms convert biodegradable organic matter to methane and carbon dioxide in the absence of dissolved oxygen and nitrate. Some of the most important aspects of the design of anaerobic digesters are related to hydraulic considerations. In spite of its important role in performance, hydraulics of flow inside digesters has not been quantified or adequately characterized. In this contribution a three-dimensional steady-state computational fluid dynamics (CFD) simulation has been performed for a particular anaerobic digester, in order to visualize the flow patterns. Flow and velocities profiles have been represented inside the digester to identify possible dead zones or stratifications. The geometry of a real digester installed in Valencia Waste Water Treatment Plant (located in Quart-Benager, Valencia, Spain) has been used in order to consider the proposed methodology.

  20. Anaerobic Digestion I. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

    Science.gov (United States)

    Arasmith, E. E.

    This lesson is the first of a two-part series on anaerobic digestion. Topics discussed include the five basic functions of an anaerobic digester, basic theory of the biological processes involved, basic equipment necessary for digestion, and the products of digestion. The lesson includes an instructor's guide and student workbook. The instructor's…

  1. 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

  2. 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.

  3. 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...

  4. 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.

  5. 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....

  6. 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.

  7. Model selection, identification and validation in anaerobic digestion: a review.

    Science.gov (United States)

    Donoso-Bravo, Andres; Mailier, Johan; Martin, Cristina; Rodríguez, Jorge; Aceves-Lara, César Arturo; Vande Wouwer, Alain

    2011-11-01

    Anaerobic digestion enables waste (water) treatment and energy production in the form of biogas. The successful implementation of this process has lead to an increasing interest worldwide. However, anaerobic digestion is a complex biological process, where hundreds of microbial populations are involved, and whose start-up and operation are delicate issues. In order to better understand the process dynamics and to optimize the operating conditions, the availability of dynamic models is of paramount importance. Such models have to be inferred from prior knowledge and experimental data collected from real plants. Modeling and parameter identification are vast subjects, offering a realm of approaches and methods, which can be difficult to fully understand by scientists and engineers dedicated to the plant operation and improvements. This review article discusses existing modeling frameworks and methodologies for parameter estimation and model validation in the field of anaerobic digestion processes. The point of view is pragmatic, intentionally focusing on simple but efficient methods.

  8. Application of Anaerobic Digestion Model No. 1 for describing anaerobic digestion of grass, maize, green weed silage, and industrial glycerine.

    Science.gov (United States)

    Biernacki, Piotr; Steinigeweg, Sven; Borchert, Axel; Uhlenhut, Frank

    2013-01-01

    Anaerobic digestion of organic waste plays an important role for the development of sustainable energy supply based on renewable resources. For further process optimization of anaerobic digestion, biogas production with the commonly used substrates, grass, maize, and green weed silage, together with industrial glycerine, were analyzed by the Weender analysis/van Soest method, and a simulation study was performed, based on the International Water Association's (IWA) Anaerobic Digestion Model No. 1 (ADM1). The simplex algorithm was applied to optimize kinetic constants for disintegration and hydrolysis steps for all examined substrates. Consequently, new parameters were determined for each evaluated substrate, tested against experimental cumulative biogas production results, and assessed against ADM1 default values for disintegration and hydrolysis kinetic constants, where the ADM1 values for mesophilic high rate and ADM1 values for solids were used. Results of the optimization lead to a precise prediction of the kinetics of anaerobic degradation of complex substrates.

  9. Anaerobic Co-Digestion of the Microalgae Scenedesmus Sp.

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Suarez, J. L.; Carreras, N.

    2011-06-07

    Microalgae biomass has been widely studied for biogas production over the last years and results show that anaerobic digestion is often limited by the low C/N ratio of this type of biomass. Therefore, codigestion with substrates of high C/N ratio is necessary. The objectives of this study are to set up an experimental method that ease reproducibility and control of anaerobic digestion processes in laboratory conditions and to determine the biodegradability and biogas production potential of the co-digestion process of microalgae Scenedesmus sp. and energy crop Opuntia ficus indica (L.) Miller. Results obtained showed that higher C/N ratios are preferred in order to maximize methane production. Highest methane yield obtained was 0.252m3CH4/Kg VS and degradability expressed as percentage COD reduced is around 30% for the ideal mixture found, made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. A laboratory setup using MicroOxymax respirometer, after its adaptation to work under anaerobic conditions, can be used for the monitoring of anaerobic digestion processes. Scenedesmus sp. as sole substrate for anaerobic digestion does not give good results due to low C/N ratio. However, when codigesting it with O. ficus-indica methane production is satisfactory. Best mixture was made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. (Author)

  10. 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.

  11. Modeling flow inside an anaerobic digester by CFD techniques

    OpenAIRE

    2011-01-01

    Anaerobic processes are used to treat high strength organic wastewater as well as for the treatment of primary and secondary sludge from conventional wastewater treatment plants. In these processes, heterotrophic microorganisms convert biodegradable organic matter to methane and carbon dioxide in the absence of dissolved oxygen and nitrate. Some of the most important aspects of the design of anaerobic digesters are related to hydraulic considerations. In spite of its impor...

  12. Anaerobic digestion: technology transfer, engineering performance and efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, F.; Traverso, P.G.; Ganapini, W.

    1987-10-01

    The chemical, technological and process aspects of anaerobic digestion process are analysed on the basis of the Authors' experience and of scientific literature. Emphasis is put on the necessity of integrating the presentation of experimental data and some suggestions are common to those of the EEC to improve the knowledge of the process. An analysis of the types of full-scale digesters used in Europe and in the USA is supplied and suggestions are proposed on the future development of anaerobic technology with the aim of improving performance and efficiency.

  13. Rapid startup and high rate nitrogen removal from anaerobic sludge digester liquor using a SNAP process.

    Science.gov (United States)

    Qiao, Sen; Nishiyama, Takashi; Fujii, Tatsuo; Bhatti, Zafar; Furukawa, Kenji

    2012-02-01

    In this study, a single-stage autotrophic nitrogen removal reactor, packed with a novel acrylic fiber biomass carrier material (Biofix), was applied for nitrogen removal from sludge digester liquor. For rapid start-up, conventional activated sludge was added to the reactor soon after the attachment of anammox biomass on the Biofix carriers, which allowed conventional activated sludge to form a protective layer of biofilm around the anammox biomass. The Nitrogen removal efficiency reached 75% within 1 week at a nitrogen loading rate of 0.46 kg-N/m(3)/day for synthetic wastewater treatment. By the end of the synthetic wastewater treatment period, the maximum nitrogen removal rate had increased to 0.92 kg-N/m(3)/day at a nitrogen loading rate of 1.0 kg-N/m(3)/day. High nitrogen removal rate was also achieved during the actual raw digester liquor treatment with the highest nitrogen removal rate being 0.83 kg-N/m(3)/day at a nitrogen loading rate of 0.93 kg-N/m(3)/day. The thick biofilm on Biofix carriers allowed anammox bacteria to survive under high DO concentration of 5-6 mg/l resulting in stable and high nitrogen removal performance. FISH and CLSM analysis demonstrated that anammox bacteria coexisted and surrounded by ammonium oxidizing bacteria.

  14. 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.

  15. 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...

  16. Identifying anaerobic digestion models using simultaneous batch experiments

    Energy Technology Data Exchange (ETDEWEB)

    Flotats, X.; Palatsi, J.; Fernandez, B.; Colomer, M. A.; Illa, J.

    2009-07-01

    As in other wastewater treatment processes, anaerobic digestion models have become a valuable tool to increase the understanding of complex biodegradation processes, to teach and to communicate using a common language, to optimize design plants and operating strategies and for trying operators and process engineers. Models require accurate and significant parameter values for being useful. (Author) 2 refs.

  17. 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.

  18. 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.

  19. Anaerobic co-digestion of dairy manure and potato waste

    Science.gov (United States)

    Yadanaparthi, Sai Krishna Reddy

    Dairy and potato are two important agricultural commodities in Idaho. Both the dairy and potato processing industries produce a huge amount of waste which could cause environmental pollution. To minimize the impact of potential pollution associated with dairy manure (DM) and potato waste (PW), anaerobic co-digestion has been considered as one of the best treatment process. The purpose of this research is to evaluate the anaerobic co-digestion of dairy manure and potato waste in terms of process stability, biogas generation, construction and operating costs, and potential revenue. For this purpose, I conducted 1) a literature review, 2) a lab study on anaerobic co-digestion of dairy manure and potato waste at three different temperature ranges (ambient (20-25°C), mesophilic (35-37°C) and thermophilic (55-57°C) with five mixing ratios (DM:PW-100:0, 90:10, 80:20, 60:40, 40:60), and 3) a financial analysis for anaerobic digesters based on assumed different capital costs and the results from the lab co-digestion study. The literature review indicates that several types of organic waste were co-digested with DM. Dairy manure is a suitable base matter for the co-digestion process in terms of digestion process stability and methane (CH4) production (Chapter 2). The lab tests showed that co-digestion of DM with PW was better than digestion of DM alone in terms of biogas and CH4 productions (Chapter 3). The financial analysis reveals DM and PW can be used as substrate for full size anaerobic digesters to generate positive cash flow within a ten year time period. Based on this research, the following conclusions and recommendations were made: ▸ The ratio of DM:PW-80:20 is recommended at thermophilic temperatures and the ratio of DM:PW-90:10 was recommended at mesophilic temperatures for optimum biogas and CH4 productions. ▸ In cases of anaerobic digesters operated with electricity generation equipment (generators), low cost plug flow digesters (capital cost of 600/cow

  20. 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

  1. Modelling of two-stage anaerobic digestion using the IWA Anaerobic Digestion Model No. 1 (ADM1).

    Science.gov (United States)

    Blumensaat, F; Keller, J

    2005-01-01

    The aim of the study presented was to implement a process model to simulate the dynamic behaviour of a pilot-scale process for anaerobic two-stage digestion of sewage sludge. The model implemented was initiated to support experimental investigations of the anaerobic two-stage digestion process. The model concept implemented in the simulation software package MATLAB/Simulink is a derivative of the IWA Anaerobic Digestion Model No.1 (ADM1) that has been developed by the IWA task group for mathematical modelling of anaerobic processes. In the present study the original model concept has been adapted and applied to replicate a two-stage digestion process. Testing procedures, including balance checks and 'benchmarking' tests were carried out to verify the accuracy of the implementation. These combined measures ensured a faultless model implementation without numerical inconsistencies. Parameters for both, the thermophilic and the mesophilic process stage, have been estimated successfully using data from lab-scale experiments described in literature. Due to the high number of parameters in the structured model, it was necessary to develop a customised procedure that limited the range of parameters to be estimated. The accuracy of the optimised parameter sets has been assessed against experimental data from pilot-scale experiments. Under these conditions, the model predicted reasonably well the dynamic behaviour of a two-stage digestion process in pilot scale.

  2. 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).

  3. 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%.

  4. 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

  5. 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.

  6. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Rejean Samson; Anh LeDuy

    1982-08-01

    Spirulina maxima algal biomass could be used as the sole nutrient for the production of biogas by anaerobic digestion process. It is relatively simple to adapt the municipal sewage sludge to this new substrate. The adapted sludge is very stable. Under nonoptimal conditions, the methane yield and productivity obtained were 0.26 m/sup 3//(kg VS added day) and 0.26 m/sup 3//(kg VS added day), respectively, with the semicontinuous, daily fed, anaerobic digestion having loading rate of 0.97 kg VS/(m/sup 3/ day), retention time of 33 days and temperature of 30/sup 0/C.

  7. Anaerobic digestion in sustainable biomass chains

    NARCIS (Netherlands)

    Pabon Pereira, C.P.

    2009-01-01

    This thesis evaluates the potential contribution of anaerobic digestion (AD) to the sustainability of biomass chains. Results provide insights in the technological potential to recover energy and valuable by-products from energy crops and residues, and evaluate biomass cascades involving AD technolo

  8. 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

  9. 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...

  10. Biogas by semi-continuous anaerobic digestion of food waste.

    Science.gov (United States)

    Zhang, Cunsheng; Su, Haijia; Wang, Zhenbin; Tan, Tianwei; Qin, Peiyong

    2015-04-01

    The semi-continuous anaerobic digestion of food waste was investigated in 1-L and 20-L continuously stirred tank reactors (CSTRs), to identify the optimum operation condition and the methane production of the semi-continuous anaerobic process. Results from a 1-L digester indicated that the optimum organic loading rate (OLR) for semi-continuous digestion is 8 g VS/L/day. The corresponding methane yield and chemical oxygen demand (COD) reduction were 385 mL/g VS and 80.2 %, respectively. Anaerobic digestion was inhibited at high OLRs (12 and 16 g VS/L/day), due to volatile fatty acid (VFA) accumulation. Results from a 20-L digester indicated that a higher methane yield of 423 mL/g VS was obtained at this larger scale. The analysis showed that the methane production at the optimum OLR fitted well with the determined kinetics equation. An obvious decrease on the methane content was observed at the initial of digestion. The increased metabolization of microbes and the activity decrease of methanogen caused by VFA accumulation explained the lower methane content at the initial of digestion.

  11. Anaerobic Digestion Scale Levels and Their Energy Yields. A comparison of energy yields of different manure-and co-digestion scale levels

    NARCIS (Netherlands)

    Konneman, Bram

    2007-01-01

    Anaerobic digestion is a biological process whereby, in the absence of oxygen, organic matter is converted into biogas and digestate. In recent years anaerobic digestion has received re-newed attention in the Dutch agricultural sector. Co-digestion, in wh

  12. Design considerations and operational performance of Anaerobic Digester: A Review

    Directory of Open Access Journals (Sweden)

    Muzaffar Ahmad Mir

    2016-04-01

    Full Text Available Due to the decline in fossil fuel reservoirs, the researchers emphasized more on the production of biogas from organic waste. Producing the renewable energy from biodegradable waste helps to overcome the energy crisis and solid waste management, done by anaerobic digestion. Anaerobic digestion is controlled breakdown of organic matter into methane gas (60%, carbon dioxide (40%, trace components along with digested used as soil conditioner. However there is vast dearth of literature regarding the design considerations. The batch digestion system yields a cost-effective and economically viable means for conversion of the food waste to useful energy. It is therefore recommended that such process can be increasingly employed in order to get and simultaneously protect the environment .This paper aims to draw key analysis and concern about the design considerations, analysis of gas production, substrates and inoculums utilization, uses and impacts of biogas.

  13. 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.

  14. Animal and industrial waste anaerobic digestion: USA status report

    Energy Technology Data Exchange (ETDEWEB)

    Lusk, P.D. [Resource Development Associates, Washington, DC (United States)

    1996-01-01

    Pollutants from unmanaged animal and bio-based industrial wastes can degrade the environment, and methane emitted from decomposing wastes may contribute to global climate change. One waste management system prevents pollution and converts a disposal problem into a new profit center. Case studies of operating systems indicate that the anaerobic digestion of animal and industrial wastes is a commercially available bioconversion technology with considerable potential for providing profitable coproducts, including a cost-effective renewable fuel. Growth and concentration of the livestock industry create opportunities to properly dispose of the large quantities of manures generated at dairy, swine, and poultry farms. Beyond the farm, extension of the anaerobic digestion process to recover methane has considerable potential for certain classified industries - with a waste stream characterization similar to livestock manures. More than 35 example industries have been identified, and include processors of chemicals, fiber, food, meat, milk, and pharmaceuticals. Some of these industries already recover methane for energy. This status report examines some current opportunities for recovering methane from the anaerobic digestion of animal and industrial wastes in the US. Case studies of operating digesters, including project and maintenance histories, and the operator`s {open_quotes}lessons learned,{close_quotes} are included as a reality check. Factors necessary for successful projects, as well as a list of reasons explaining why some anaerobic digestion projects fail, are provided. The role of management is key; not only must digesters be well engineered and built with high-quality components, they must also be sited at facilities willing to incorporate the uncertainties of a new technology. Anaerobic digestion can provide monetary benefits and mitigate possible pollution problems, thereby sustaining development while maintaining environmental quality.

  15. 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.

  16. Anaerobic sludge digestion with a biocatalytic additive. [Lactobacillus acidophilus

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S.; Henry, M.P.; Fedde, P.A.

    1982-01-01

    Aimed at improving the process operating characteristics of anaerobic digestion for sludge stabilization and SNG production, this study evaluates the effects of a lactobacillus additive under normal, variable, and overload conditions. This whey fermentation product of an acid-tolerant strain of L. acidophilus fortified with CoCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. Data indicate that the biochemical additive increases methane yield, gas production rate, and volatile solids reduction; decreases volatile acids accumulation; enhances the digester buffer capacity; and improves the fertilizer value and dewatering characteristics of the digested residue. Digester capacities could be potentially doubled when the feed is so treated. Results of field tests with six full-scale digesters confirm observations made with bench-scale digesters.

  17. Inactivation of Selected Bacterial Pathogens in Dairy Cattle Manure by Mesophilic Anaerobic Digestion (Balloon Type Digester

    Directory of Open Access Journals (Sweden)

    Christy E. Manyi-Loh

    2014-07-01

    Full Text Available Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%–99% reduced in the order: Campylobacter sp. (18 days < Escherichia coli sp. (62 days < Salmonella sp. (133 days from a viable count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure, respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.

  18. Inactivation of selected bacterial pathogens in dairy cattle manure by mesophilic anaerobic digestion (balloon type digester).

    Science.gov (United States)

    Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael

    2014-07-14

    Anaerobic digestion of animal manure in biogas digesters has shown promise as a technology in reducing the microbial load to safe and recommended levels. We sought to treat dairy manure obtained from the Fort Hare Dairy Farm by investigating the survival rates of bacterial pathogens, through a total viable plate count method, before, during and after mesophilic anaerobic digestion. Different microbiological media were inoculated with different serial dilutions of manure samples that were withdrawn from the biogas digester at 3, 7 and 14 day intervals to determine the viable cells. Data obtained indicated that the pathogens of public health importance were 90%-99% reduced in the order: Campylobacter sp. (18 days) count of 10.1 × 103, 3.6 × 105, 7.4 × 103 to concentrations below the detection limit (DL = 102 cfu/g manure), respectively. This disparity in survival rates may be influenced by the inherent characteristics of these bacteria, available nutrients as well as the stages of the anaerobic digestion process. In addition, the highest p-value i.e., 0.957 for E. coli showed the statistical significance of its model and the strongest correlation between its reductions with days of digestion. In conclusion, the results demonstrated that the specific bacterial pathogens in manure can be considerably reduced through anaerobic digestion after 133 days.

  19. 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.

  20. 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.

  1. 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)

  2. Improvement of anaerobic digestion control from urban sludges; Mejora del control de la digestion anaerobia de fangos urbanos

    Energy Technology Data Exchange (ETDEWEB)

    Minguez Gabina, R.

    2002-07-01

    Due to its many advantages, the anaerobic digestion is a widespread choice in our water treatment plants. Furthermore, the companies demand an optimization of the control of the process. Until today, the practice of the operation has been made modifying the conditions of the digester by controlling the outlet parameters of the digestion, so that a delay in the application of the corrections is enough to decrease the performance. The investigation concludes that the most secure way to drive an anaerobic digester is to mange a strict control of the inlet parameters into digestion process. (Author)

  3. Ultrasonic treatment to improve anaerobic digestibility of dairy waste streams.

    Science.gov (United States)

    Palmowski, L; Simons, L; Brooks, R

    2006-01-01

    The dairy-processing industry generates various types of organic wastes, which are utilised as stock feed, for anaerobic digestion, spread on land or alternatively land-filled at high costs. Owing to the generation of renewable energy, anaerobic digestion is an attractive option for many factories. To enhance the biological degradation process, a mechanical disintegration of various waste dairy streams was undertaken. While the successful application of ultrasonic treatment has been reported for various municipal waste streams, limited information was available for dairy industry applications. The results of this study showed that ultrasonic treatment can improve the digestibility of the more problematic dairy waste streams, such as sludges, by breaking down micro-organisms' cell walls and releasing soluble cell compounds. For more soluble streams, such as dairy factory effluent, an increased gas production was observed and attributed to the reduced particle size of the fat globules.

  4. 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...

  5. 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.

  6. 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.

  7. Enhancing post anaerobic digestion of full-scale anaerobically digested sludge using free nitrous acid treatment.

    Science.gov (United States)

    Zhang, Tingting; Wang, Qilin; Ye, Liu; Yuan, Zhiguo

    2016-05-01

    In some wastewater treatment plants (WWTPs), the ever increasing production of sludge with the expanding population overloaded the anaerobic digestion which compromises the sludge reduction efficiency. Post anaerobic digestion of anaerobically digested sludge (ADS) has been applied to enhance sludge reduction, however, to a very limited extent. This study verified the effectiveness of free nitrous acid (FNA i.e. HNO2) pre-treatment on enhancing full-scale ADS degradation in post anaerobic digestion. The ADS collected from a full-scale WWTP was subject to FNA treatment at concentrations of 0.77, 1.54, 2.31, 3.08, and 3.85 mg N/L for 24 h followed by biochemical methane potential tests. The FNA treatment at all concentrations resulted in an increase (from 1.5-3.1 % compared to the control) in sludge reduction with the highest improvement achieved at 0.77 mg HNO2-N/L. The FNA treatment at this concentration also resulted in the highest increase in methane production (40 %) compared to the control. The economic analysis indicates that FNA treatment is economically attractive for enhancing post anaerobic digestion of full-scale ADS.

  8. Dynamic real-time substrate feed optimization of anaerobic co-digestion plants

    NARCIS (Netherlands)

    Gaida, Daniel

    2014-01-01

    In anaerobic co-digestion plants a mix of organic materials is converted to biogas using the anaerobic digestion process. These organic materials, called substrates, can be crops, sludge, manure, organic wastes and many more. They are fed on a daily basis and significantly affect the biogas producti

  9. Whole farm impact of anaerobic digestion and biogas use on a New York dairy farm

    Science.gov (United States)

    Anaerobic digestion of manure for biogas production is one of many options for reducing the carbon footprint of milk production. This process reduces greenhouse gas emissions but increases the potential nitrogen and phosphorus losses from the farm. An anaerobic digester component was added to the In...

  10. 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.

  11. 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.

  12. Anaerobic digestion of yard waste with hydrothermal pretreatment.

    Science.gov (United States)

    Li, Wangliang; Zhang, Guangyi; Zhang, Zhikai; Xu, Guangwen

    2014-03-01

    The digestibility of lignocellulosic biomass is limited by its high content of refractory components. The objective of this study is to investigate hydrothermal pretreatment and its effects on anaerobic digestion of sorted organic waste with submerged fermentation. Hydrothermal pretreatment (HT) was performed prior to anaerobic digestion, and three agents were examined for the HT: hot compressed water, alkaline solution, and acidic solution. The concentrations of glucose and xylose were the highest in the sample pretreated in acidic solution. Compared with that of the untreated sample, the biogas yields from digesting the samples pretreated in alkaline solution, acidic solution, and hot water increased by 364, 107, and 79%, respectively. The decrease of chemical oxygen demand (COD) in liquid phase followed the same order as for the biogas yield. The initial ammonia content of the treated samples followed the order sample treated in acidic solution > sample treated in alkaline solution > sample treated in hot water. The concentrations of volatile fatty acids (VFAs) were low, indicating that the anaerobic digestion process was running at continuously stable conditions.

  13. The role of anaerobic digestion in the emerging energy economy.

    Science.gov (United States)

    Batstone, Damien John; Virdis, Bernardino

    2014-06-01

    Anaerobic digestion is the default process for biological conversion of residue organics to renewable energy and biofuel in the form of methane. However, its scope of application is expanding, due to availability of new technologies, and the emerging drivers of energy and nutrient conservation and recovery. Here, we outline two of these new application areas, namely wastewater nutrient and energy recovery, and generation of value added chemicals through mixed culture biotechnology. There exist two options for nutrient and energy recovery from domestic wastewater: low energy mainline and partition-release-recovery. Both are heavily dependent on anaerobic digestion as an energy generating and nutrient release step, and have been enabled by new technologies such as low emission anaerobic membrane processes. The area of mixed culture biotechnology has been previously identified as a key industrial opportunity, but is now moving closer to application due application of existing and new technologies. As well as acting as a core technology option in bioproduction, anaerobic digestion has a key role in residual waste valorization and generation of energy for downstream processing. These new application areas and technologies are emerging simultaneously with substantial advances in knowledge of underlying mechanisms such as electron transfer, understanding of which is critical to development of the new application areas.

  14. Anaerobic sludge digestion with a biocatalytic additive

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, S.; Henry, M.P.; Fedde, P.A.

    1982-01-01

    The objective of this research was to evaluate the effects of a lactobacillus additive an anaerobic sludge digestion under normal, variable, and overload operating conditions. The additive was a whey fermentation product of an acid-tolerant strain of Lactobacillus acidophilus fortified with CaCO/sub 3/, (NH/sub 4/)/sub 2/HPO/sub 4/, ferrous lactate, and lactic acid. The lactobacillus additive is multifunctional in nature and provides growth factors, metabolic intermediates, and enzymes needed for substrate degradation and cellular synthesis. The experimental work consisted of several pairs of parallel mesophilic (35/sup 0/C) digestion runs (control and test) conducted in five experimental phases. Baseline runs without the additive showed that the two experimental digesters had the same methane content, gas production rate (GPR), and ethane yield. The effect of the additive was to increase methane yield and GPR by about 5% (which was statistically significant) during digester operation at a loading rate (LR) of 3.2 kg VS/m/sup 3/-day and a hydraulic retention time (HRT) of 14 days. Data collected from the various experimental phases showed that the biochemical additive increased methane yield, gas production rate, and VS reduction, and decreased volatile acids accumulation. In addition, it enhanced digester buffer capacity and improved the fertilizer value and dewatering characteristics of the digested residue.

  15. Anaerobic digestion in the treatment of waste and wastewater effluent; Digestion anaerobia en el tratamiento de efluentes y lodos residuales

    Energy Technology Data Exchange (ETDEWEB)

    Baraza, X.; Galimary, F.; Torres, R.

    2003-07-01

    Anaerobic digestion is one of the processes most commonly employed at the present time in treating effluent and wastewater containing a large proportion of organic matter. This article describes the process involved and its applications in the environmental engineering field. It also discusses the physical, chemical and biological factors influencing anaerobic digestion and which therefore have a bearing on whether to implements this process and how it is actually applied from a technological point of view. (Author) 125 refs.

  16. 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.

  17. A generic and systematic procedure to derive a simplified model from the Anaerobic Digestion Model No. 1 (ADM1)

    OpenAIRE

    Ficara, E.; Leva, A.; Harmand, Jérôme

    2015-01-01

    The Anaerobic Digestion Model No.1 (ADM1) developed by the IWA Task Group for mathematical modelling of anaerobic digestion processes (Batstone et al. (2001) [1]) is a structural model which describes the main biochemical and physicochemical processes. For such purposes, other models have been proposed to describe anaerobic processes with a reduced set of parameters, state variables and processes. Among them, the Anaerobic Model No. 2 (AM2) proposed by Bernard et al. (2001) [2] which describe...

  18. Optimization of solid state anaerobic digestion of the OFMSW by digestate recirculation: A new approach

    Energy Technology Data Exchange (ETDEWEB)

    Michele, Pognani, E-mail: michele.pognani@unimi.it [Gruppo Ricicla – DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano (Italy); Giuliana, D’Imporzano, E-mail: giuliana.dimporzano@unimi.it [Gruppo Ricicla – DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano (Italy); Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Biomass and Bioenergy Lab., Parco Tecnologico Padano, Via Einstein, Loc. C.na Codazza, 26900 Lodi (Italy); Carlo, Minetti, E-mail: carlo.minetti@a2a.eu [Ecodeco, a2a Group, Cascina Darsena 1, 27010 Giussago, Pavia (Italy); Sergio, Scotti, E-mail: sergio.scotti@a2a.eu [Ecodeco, a2a Group, Cascina Darsena 1, 27010 Giussago, Pavia (Italy); Fabrizio, Adani, E-mail: farbrizio.adani@unimi.it [Gruppo Ricicla – DiSAA, Università degli Studi di Milano, Soil and Env. Lab, Via Celoria, 2, 20133 Milano (Italy); Gruppo Ricicla - DiSAA, Università degli Studi di Milano, Biomass and Bioenergy Lab., Parco Tecnologico Padano, Via Einstein, Loc. C.na Codazza, 26900 Lodi (Italy)

    2015-01-15

    Highlights: • Solid State Anaerobic Digestion (SSAD) of OFMSW can be optimized by irrigation with digestate. • Digestate spreading allows keeping optimal process parameters and high hydrolysis rate. • The 18.4% of CH{sub 4} was produced in the reactor, leaving the 49.7% in the percolate. • Successive CSTR feed with percolate shows a biogas enriched in methane (more than 80%). • The proposed process allow producing the 68% of OFMSW potential CH{sub 4}, getting high quality organic amendment. - Abstract: Dry anaerobic digestion (AD) of OFMSW was optimized in order to produce biogas avoiding the use of solid inoculum. Doing so the dry AD was performed irrigating the solid waste with liquid digestate (flow rate of 1:1.18–1:0.9 w/w waste/digestate; 21 d of hydraulic retention time – HRT) in order to remove fermentation products inhibiting AD process. Results indicated that a high hydrolysis rate of organic matter (OM) and partial biogas production were obtained directly during the dry AD. Hydrolysate OM was removed from digester by the percolate flow and it was subsequently used to feed a liquid anaerobic digester. During dry AD a total loss of 36.9% of total solids was recorded. Methane balance indicated that 18.4% of potential methane can be produced during dry AD and 49.7% by the percolate. Nevertheless results obtained for liquid AD digestion indicated that only 20.4% and 25.7% of potential producible methane was generated by adopting 15 and 20 days of HRT, probably due to the AD inhibition due to high presence of toxic ammonia forms in the liquid medium.

  19. Large eddy simulation of mechanical mixing in anaerobic digesters.

    Science.gov (United States)

    Wu, Binxin

    2012-03-01

    A comprehensive study of anaerobic digestion requires an advanced turbulence model technique to accurately predict mixing flow patterns because the digestion process that involves mass transfer between anaerobes and their substrates is primarily dependent on detailed information about the fine structure of turbulence in the digesters. This study presents a large eddy simulation (LES) of mechanical agitation of non-Newtonian fluids in anaerobic digesters, in which the sliding mesh method is used to characterize the impeller rotation. The three subgrid scale (SGS) models investigated are: (i) Smagorinsky-Lilly model, (ii) wall-adapting local eddy-viscosity model, and (iii) kinetic energy transport (KET) model. The simulation results show that the three SGS models produce very similar flow fields. A comparison of the simulated and measured axial velocities indicates that the LES profile shapes are in general agreement with the experimental data but they differ markedly in velocity magnitudes. A check of impeller power and flow numbers demonstrates that all the SGS models give excellent predictions, with the KET model performing the best. Moreover, the performance of six Reynolds-averaged Navier-Stokes turbulence models are assessed and compared with the LES results.

  20. 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.

  1. Microbial electrochemical monitoring of volatile fatty acids during anaerobic digestion

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Angelidaki, Irini; Zhang, Yifeng

    2016-01-01

    Volatile fatty acid (VFA) concentration is known as an important indicator to control and optimize anaerobic digestion (AD) process. In this study, an innovative VFA biosensor was developed based on the principle of a microbial desalination cell. The correlation between current densities and VFA...... concentrations was firstly evaluated with synthetic digestate. Two linear relationships were observed between current densities and VFA levels from 1 to 30 mM (0.04 to 8.50 mA/m2, R2=0.97) and then from 30 to 200 mM (8.50 to 10.80 mA/m2, R2=0.95). The detection range was much broader than that of other existing...... and reliable measurement of VFA levels during AD and other anaerobic processes....

  2. ANAEROBIC DIGESTION AND THE DENITRIFICATION IN UASB REACTOR

    Directory of Open Access Journals (Sweden)

    José Tavares de Sousa

    2008-01-01

    Full Text Available The environmental conditions in Brazil have been contributing to the development of anaerobic systems in the treatment of wastewaters, especially UASB - Upflow Anaerobic Sludge Blanket reactors. The classic biological process for removal of nutrients uses three reactors - Bardenpho System, therefore, this work intends an alternative system, where the anaerobic digestion and the denitrification happen in the same reactor reducing the number of reactors for two. The experimental system was constituted by two units: first one was a nitrification reactor with 35 L volume and 15 d of sludge age. This system was fed with raw sanitary waste. Second unit was an UASB, with 7.8 L and 6 h of hydraulic detention time, fed with ¾ of effluent nitrification reactor and ¼ of raw sanitary waste. This work had as objective to evaluate the performance of the UASB reactor. In terms of removal efficiency, of bath COD and nitrogen, it was verified that the anaerobic digestion process was not affected. The removal efficiency of organic material expressed in COD was 71%, performance already expected for a reactor of this type. It was also observed that the denitrification process happened; the removal nitrate efficiency was 90%. Therefore, the denitrification process in reactor UASB is viable.

  3. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Samson, R.; LeDuy, A.

    1982-08-01

    The photosynthetic spectrum of solar energy could be exploited for the production of chemical energy of methane through the combined algal-bacterial process. In this process, the algae are mass produced from light and from carbon in the first step. The algal biomass is then used as a nutrient for feeding the anaerobic digester, in the second step, for the production of methane by anaerobic bacteria. The carbon source for the production of algal biomass could be either organic carbon from wastewaters (for eucaryotic algae), or carbon dioxide from the atmosphere or from the combustion exhaust gases (for both prokaryotic and eukaryotic algae). The technical feasibility data on the anaerobic digestion of algal biomass have been reported for many species of algae including macroscopic algae and microscopic algae. Research being conducted in the authors' laboratory consists of using the semimicroscopic blue-green alga Spirulina maxima as the sole substrate for this combined algal-bacterial process. This species of alga is very attractive for the process because of its capability of using the atmospheric carbon dioxide as carbon source and its simple harvesting methods. Furthermore, it appeared that the fermentability of S. maxima is significantly higher than other microscopic algae. This communication presents the results on the anaerobic inoculum development by the adaptation technique. This inoculum was then used for the semicontinuous anaerobic digestion of S. maxima algal biomass. The evolutions of biogas production and composition, biogas yield, total volatile fatty acids, alkalinity, ammonia nitrogen, pH, and electrode potential were followed.

  4. Anaerobic digestion of pulp and paper mill wastewater and sludge.

    Science.gov (United States)

    Meyer, Torsten; Edwards, Elizabeth A

    2014-11-15

    Pulp and paper mills generate large amounts of waste organic matter that may be converted to renewable energy in form of methane. The anaerobic treatment of mill wastewater is widely accepted however, usually only applied to few selected streams. Chemical oxygen demand (COD) removal rates in full-scale reactors range between 30 and 90%, and methane yields are 0.30-0.40 m(3) kg(-1) COD removed. Highest COD removal rates are achieved with condensate streams from chemical pulping (75-90%) and paper mill effluents (60-80%). Numerous laboratory and pilot-scale studies have shown that, contrary to common perception, most other mill effluents are also to some extent anaerobically treatable. Even for difficult-to-digest streams such as bleaching effluents COD removal rates range between 15 and 90%, depending on the extent of dilution prior to anaerobic treatment, and the applied experimental setting. Co-digestion of different streams containing diverse substrate can level out and diminish toxicity, and may lead to a more robust microbial community. Furthermore, the microbial population has the ability to become acclimated and adapted to adverse conditions. Stress situations such as toxic shock loads or temporary organic overloading may be tolerated by an adapted community, whereas they could lead to process disturbance with an un-adapted community. Therefore, anaerobic treatment of wastewater containing elevated levels of inhibitors or toxicants should be initiated by an acclimation/adaptation period that can last between a few weeks and several months. In order to gain more insight into the underlying processes of microbial acclimation/adaptation and co-digestion, future research should focus on the relationship between wastewater composition, reactor operation and microbial community dynamics. The potential for engineering and managing the microbial resource is still largely untapped. Unlike in wastewater treatment, anaerobic digestion of mill biosludge (waste activated

  5. Anaerobic digestion of pot-ale

    Energy Technology Data Exchange (ETDEWEB)

    Mosey, F.E.

    1990-12-01

    In the production of whisky, the fermented wash is distilled twice and each bushel of grain yields about 15.5 gallons of pot-ale, 6.0 gallons of spent lees and 2.7 gallons of proof spirit. Disposal of pot-ale, the strong residue from the first distillation, containing all the non-volatile and unfermented components of the wash, will always be difficult. Anaerobic digestion provides a possible option. By destroying most of the biodegradable solids and converting them to biogas, it provides an intermediate effluent which conventional treatment technology can purify to river discharge standards. Pilot-scale trials confirm that pot-ale can be treated by anaerobic digestion. The most severe problems are the high purification efficiencies required to achieve UK river discharge standards and the quality and settling properties of the biological sludges produced. To achieved these standards, the design and operation of the entire treatment chain is dominated by the need to capture and concentrate suspended solids (SS) produced by the biological fermentations. Overall performance targets are 99.95% removal of biological oxygen demand (BOD), 99% removal of ammonia and a surplus sludge production of less than 20% of the incoming flow. (author).

  6. TEST RESULTS FOR FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS

    Science.gov (United States)

    EPA, in conjunction with ONSI Corp., embarked on a project to define, design, test, and assess a fuel cell energy recovery system for application at anaerobic digester waste water (sewage) treatment plants. Anaerobic digester gas (ADG) is produced at these plants during the proce...

  7. Winery and distillery wastewater treatment by anaerobic digestion.

    Science.gov (United States)

    Moletta, R

    2005-01-01

    Anaerobic digestion is widely used for wastewater treatment, especially in the food industries. Generally after the anaerobic treatment there is an aerobic post-treatment in order to return the treated water to nature. Several technologies are applied for winery wastewater treatment. They are using free cells or flocs (anaerobic contact digesters, anaerobic sequencing batch reactors and anaerobic lagoons), anaerobic granules (Upflow Anaerobic Sludge Blanket--UASB), or biofilms on fixed support (anaerobic filter) or on mobile support as with the fluidised bed. Some technologies include two strategies, e.g. a sludge bed with anaerobic filter as in the hybrid digester. With winery wastewaters (as for vinasses from distilleries) the removal yield for anaerobic digestion is very high, up to 90-95% COD removal. The organic loads are between 5 and 15 kgCOD/m3 of digester/day. The biogas production is between 400 and 600 L per kg COD removed with 60 to 70% methane content. For anaerobic and aerobic post-treatment of vinasses in the Cognac region, REVICO company has 99.7% COD removal and the cost is 0.52 Euro/m3 of vinasses.

  8. Hygiene tests in the anaerobic digestion of household refuse

    Energy Technology Data Exchange (ETDEWEB)

    Maier, H.; Philipp, W.; Wekerle, J.; Strauch, D.

    In a pilot plant the disinfecting effect of composting the effluent of an anaerobic mesophilic digestion process of the organic fraction of household refuse was investigated. The dewatered effluent was mixed with straw as bulking material, put in not aerated windrows and aerobically composted. It was further investigated whether the influent of the digester could be disinfected with lime milk prior to the anaerobic mesophilic digestion process. For the evaluation of the disinfection salmonellas, enterococci, klebsiellas, parvo-, polio- and rotavirus were used as test agents. Temperature, total aerobic germ count, enterobacteriaceae and coliforms were also considered. The effect of lime milk in the influent on the digestion process, survival of the test bacteria and gas production was also studied. Both treatments can result in a hygienically safe product. But composting under the conditions given should not be operated during the winter period. Lime treatment of the influent results in a disinfection of the effluent which immediately can be utilized as liquid sludge in agriculture. (orig.)

  9. 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.

  10. Batch anaerobic co-digestion of waste activated sludge and microalgae (Chlorella sorokiniana) at mesophilic temperature.

    Science.gov (United States)

    Beltrán, Carolina; Jeison, David; Fermoso, Fernando G; Borja, Rafael

    2016-08-23

    The microalgae Chlorella sorokiniana are used as co-substrate for waste activated sludge (WAS) anaerobic digestion. The specific objective of this research was to evaluate the feasibility of improving methane production from anaerobic digestion of WAS in co-digestion with this microalga, based on an optimized mixture percentage. Thus, the anaerobic co-digestion of both substrates aims to overcome the drawbacks of the anaerobic digestion of single WAS, simultaneously improving its management. Different co-digestion mixtures (0% WAS-100% microalgae; 25% WAS-75% microalgae; 50% WAS-50% microalgae; 75% WAS-25% microalgae; 100% WAS-0% microalgae) were studied. The highest methane yield (442 mL CH4/g VS) was obtained for the mixture with 75% WAS and 25% microalgae. This value was 22% and 39% higher than that obtained in the anaerobic digestion of the sole substrates WAS and microalgae, respectively, as well as 16% and 25% higher than those obtained for the co-digestion mixtures with 25% WAS and 75% microalgae and 50% WAS and 50% microalgae, respectively. The kinetic constant of the process increased 42%, 42% and 12%, respectively, for the mixtures with 25%, 50% and 75% of WAS compared to the substrate without WAS. Anaerobic digestion of WAS, together with C. sorokiniana, has been clearly improved by ensuring its viability, suitability and efficiency.

  11. CFD simulation of anaerobic digester with variable sewage sludge rheology.

    Science.gov (United States)

    Craig, K J; Nieuwoudt, M N; Niemand, L J

    2013-09-01

    A computational fluid dynamics (CFD) model that evaluates mechanical mixing in a full-scale anaerobic digester was developed to investigate the influence of sewage sludge rheology on the steady-state digester performance. Mechanical mixing is provided through an impeller located in a draft tube. Use is made of the Multiple Reference Frame model to incorporate the rotating impeller. The non-Newtonian sludge is modeled using the Hershel-Bulkley law because of the yield stress present in the fluid. Water is also used as modeling fluid to illustrate the significant non-Newtonian effects of sewage sludge on mixing patterns. The variation of the sewage sludge rheology as a result of the digestion process is considered to determine its influence on both the required impeller torque and digester mixing patterns. It was found that when modeling the fluid with the Hershel-Bulkley law, the high slope of the sewage stress-strain curve at high shear rates causes significant viscous torque on the impeller surface. Although the overall fluid shear stress property is reduced during digestion, this slope is increased with sludge age, causing an increase in impeller torque for digested sludge due to the high strain rates caused by the pumping impeller. Consideration should be given to using the Bingham law to deal with high strain rates. The overall mixing flow patterns of the digested sludge do however improve slightly.

  12. [Agroindustrial wastes methanization and bacterial composition in anaerobic digestion].

    Science.gov (United States)

    González-Sánchez, María E; Pérez-Fabiel, Sergio; Wong-Villarreal, Arnoldo; Bello-Mendoza, Ricardo; Yañez-Ocampo, Gustavo

    2015-01-01

    The tons of organic waste that are annually generated by agro-industry, can be used as raw material for methane production. For this reason, it is important to previously perform biodegradability tests to organic wastes for their full scale methanization. This paper addresses biodegradability, methane production and the behavior of populations of eubacteria and archaeabacteria during anaerobic digestion of banana, mango and papaya agroindustrial wastes. Mango and banana wastes had higher organic matter content than papaya in terms of their volatile solids and total solid rate (94 and 75% respectively). After 63 days of treatment, the highest methane production was observed in banana waste anaerobic digestion: 63.89ml CH4/per gram of chemical oxygen demand of the waste. In the PCR-DGGE molecular analysis, different genomic footprints with oligonucleotides for eubacteria and archeobacteria were found. Biochemical methane potential results proved that banana wastes have the best potential to be used as raw material for methane production. The result of a PCR- DGGE analysis using specific oligonucleotides enabled to identify the behavior of populations of eubacteria and archaeabacteria present during the anaerobic digestion of agroindustrial wastes throughout the process.

  13. 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.

  14. Biomass stabilization in the anaerobic digestion of wastewater sludges

    Energy Technology Data Exchange (ETDEWEB)

    Arnaiz, C. [Universidad de Sevilla, Dept. de Ingenieria Quimica y Ambiental, Sevilla (Spain); Gutierrez, J.C. [Universidad Pablo de Olavide, Dept. de Ciencias Ambientales, Sevilla (Spain); Lebrato, J. [Universidad de Sevilla, Grupo Tratamiento de Aguas Residuales, Sevilla (Spain)

    2005-07-01

    Sludge stabilization processes include both volatile solid destruction and biomass stabilization. Traditionally, both processes have been considered together, in such a way that, when volatile solid destruction is achieved, the biomass is considered stabilized. In this study, volatile solids reduction and biomass stabilization in the anaerobic digestion of primary, secondary and mixed sludges from municipal wastewater treatment plants were researched in batch cultures by measurements of suspended solids and suspended lipid-phosphate. The estimated kinetic constants were higher in all sludge types tested for the biomass stabilization process, indicating that volatile solids destruction and biomass stabilization are not parallel processes, since the latter one is reached before the former. (Author)

  15. Biomass stabilization in the anaerobic digestion of wastewater sludges

    Energy Technology Data Exchange (ETDEWEB)

    Arnaiz, C. [Universidad de Sevilla (Spain). Escuela Universitaria Politecnica. Departamento de Ingenieria Quimica y Ambiental; Gutierrez, J.C. [Universidad Pablo de Olavide, Sevilla (Spain). Departamento de Ciencias Ambientales; Lebrato, J. [Universidad de Sevilla (Spain). Escuela Universitaria Politecnica

    2006-07-15

    Sludge stabilization processes include both volatile solid destruction and biomass stabilization. Traditionally, both processes have been considered together, in such a way that, when volatile solid destruction is achieved, the biomass is considered stabilized. In this study, volatile solids reduction and biomass stabilization in the anaerobic digestion of primary, secondary and mixed sludges from municipal wastewater treatment plants were researched in batch cultures by measurements of suspended solids and suspended lipid-phosphate. The estimated kinetic constants were higher in all sludge types tested for the biomass stabilization process, indicating that volatile solids destruction and biomass stabilization are not parallel processes, since the latter one is reached before the former. (author)

  16. Anaerobic co-digestion in the Netherlands. A system analysis on greenhouse gas emissions from Dutch co-digesters.

    NARCIS (Netherlands)

    Groenewold, Henk

    2013-01-01

    Summary Anaerobic digestion (AD) is a biological process whereby, in the absence of oxygen, organic matter is transformed into biogas and digestate. In recent years AD has received new attention in the Dutch agricultural sector by introducing the co-dige

  17. 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.

  18. State-of-the-art of anaerobic digestion technology for industrial wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Rajeshwari, K.V.; Balakrishnan, M.; Kansal, A.; Kusum Lata; Kishore, V.V.N. [Tata Energy Research Institute, New Delhi (India). Darbari Seth Block

    2000-06-01

    Anaerobic digestion is the most suitable option for the treatment of high strength organic effluents. The presence of biodegradable components in the effluents coupled with the advantages of anaerobic process over other treatment methods makes it an attractive option. This paper reviews the suitability and the status of development of anaerobic reactors for the digestion of selected organic effluents from sugar and distillery, pulp and paper, slaughterhouse and dairy units. In addition, modifications in the existing reactor designs for improving the efficiency of digestion has also been suggested. (author)

  19. Anaerobic co-digestion of sewage sludge and food waste.

    Science.gov (United States)

    Prabhu, Meghanath S; Mutnuri, Srikanth

    2016-04-01

    Anaerobic co-digestion of organic matter improves digester operating characteristics and its performance. In the present work, food waste was collected from the institute cafeteria. Two types of sludge (before centrifuge and after centrifuge) were collected from the fluidised bed reactor of the institute treating sewage wastewater. Food waste and sludge were studied for their physico-chemical characteristics, such as pH, chemical oxygen demand, total solids, volatile solids, ammoniacal nitrogen, and total nitrogen. A biomethane potential assay was carried out to find out the optimum mixing ratio of food waste and sludge for anaerobic co-digestion. Results indicated that food waste mixed with sludge in the ratio of 1:2 produced the maximum biogas of 823 ml gVS(-1)(21 days) with an average methane content of 60%. Batch studies were conducted in 5 L lab-glass reactors at a mesophilic temperature. The effect of different substrate loading rates on biogas production was investigated. The mixing ratio of food waste and sludge was 1:2. A loading rate of 1 gVS L d(-1)gave the maximum biogas production of 742 ml g(-1)VS L d(-1)with a methane content of 50%, followed by 2 gVS L d(-1)with biogas of 539 ml g(-1)VS L d(-1) Microbial diversity of the reactor during fed batch studies was investigated by terminal restriction fragment length polymorphism. A pilot-scale co-digestion of food waste and sludge (before centrifuge) indicated the process stability of anaerobic digestion.

  20. Biogas production from anaerobic digestion of Spirulina maxima algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Samson, R.; LeDuy, A.

    1982-08-01

    The semimicroscopic blue-green alga Spirulina maxima makes an ideal substrate for anaerobic digestion because it is easy to harvest, it can use carbon dioxide from the atmosphere as its carbon source, and its fermentability is higher than that of other small algae. Digestion experiments demonstrated that S. maxima can serve as the sole nutrient for biogas production and that municipal sewage sludge, when adapted to this new substrate, is very stable. During semicontinuous daily-fed trials under non-optimal conditions at an 0.06 lb volatile solids (VS)/ft/sup 3/ (0.97 kg VS/m/sup 3/) loading rate, 33-day retention time, and 86/sup 0/F (30/sup 0/C) digestion temperature, the daily methane yield was 4.2 CF/lb (0.26 m/sup 3//kg) VS added, which represents 47% of the maximum theoretical yield. Studies on optimizing the process are underway.

  1. 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。

  2. Anaerobic digestion of lignocellulosic biomass: challenges and opportunities.

    Science.gov (United States)

    Sawatdeenarunat, Chayanon; Surendra, K C; Takara, Devin; Oechsner, Hans; Khanal, Samir Kumar

    2015-02-01

    Anaerobic digestion (AD) of lignocellulosic biomass provides an excellent opportunity to convert abundant bioresources into renewable energy. Rumen microorganisms, in contrast to conventional microorganisms, are an effective inoculum for digesting lignocellulosic biomass due to their intrinsic ability to degrade substrate rich in cellulosic fiber. However, there are still several challenges that must be overcome for the efficient digestion of lignocellulosic biomass. Anaerobic biorefinery is an emerging concept that not only generates bioenergy, but also high-value biochemical/products from the same feedstock. This review paper highlights the current status of lignocellulosic biomass digestion and discusses its challenges. The paper also discusses the future research needs of lignocellulosic biomass digestion.

  3. A simplified stoichiometric kinetic model for estimating the concentration of reaction products in anaerobic digestion.

    Science.gov (United States)

    Kim, Moonil; Cui, Fenghao

    2016-12-29

    Modelling the anaerobic digestion process is often complex and needs to consider many input parameters. This study simplified the modelling procedure by developing an idealized stoichiometric kinetic model that simulates the anaerobic digestion process with only a few parameters: composition coefficients (α and β), maximum substrate utilization rate (qmax), endogenous-decay coefficient (b), biodegradable fraction (fd), and temperature coefficient (Ф). We validated the model with the operating results of a pilot two-phase anaerobic digester for food wastewater disposal and calculated using the MATLAB programing software. The comparison between the experimental and model simulation results demonstrated a good agreement. The developed model correctly simulated the fate of chemicals in the anaerobic digestion process.

  4. Comparison of digestate from solid anaerobic digesters and dewatered effluent from liquid anaerobic digesters as inocula for solid state anaerobic digestion of yard trimmings.

    Science.gov (United States)

    Xu, Fuqing; Wang, Feng; Lin, Long; Li, Yebo

    2016-01-01

    To select a proper inoculum for the solid state anaerobic digestion (SS-AD) of yard trimmings, digestate from solid anaerobic digesters and dewatered effluent from liquid anaerobic digesters were compared at substrate-to-inoculum (S/I) ratios from 0.2 to 2 (dry basis), and total solids (TS) contents from 20% to 35%. The highest methane yield of around 244L/kg VSfeed was obtained at an S/I ratio of 0.2 and TS content of 20% for both types of inoculum. The highest volumetric methane productivity was obtained with dewatered effluent at an S/I ratio of 0.6 and TS content of 24%. The two types of inoculum were found comparable regarding methane yields and volumetric methane productivities at each S/I ratio, while using dewatered effluent as inoculum reduced the startup time. An S/I ratio of 1 was determined to be a critical level and should be set as the upper limit for mesophilic SS-AD of yard trimmings.

  5. Inactivation of dairy manure-borne pathogens by anaerobic digestion

    Science.gov (United States)

    Background: Anaerobic digestion of animal manure has the potential to inactivate enteric pathogens, thereby reducing exposures to livestock and humans when the products of digestion are disposed by land-spreading or irrigation or returned to livestock uses such as bedding. Data on digester effectiv...

  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. 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...

  8. Biogas recovery from microwave heated sludge by anaerobic digestion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Biogas generated from sewage sludge,livestock waste,and food waste by anaerobic digestion is a valuable renewable energy resource.However,conventional anaerobic digestion is not an efficient process.A long hydraulic retention time and low biogas recovery rate hinder the applications of those resources.An effective pretreatment method to destroy sludge microbial cells has been one of the major concerns regarding improvement of the biogas production.This article focuses on the effects of microwave heating on sludge anaerobic digestion.Volatile suspended solid(VSS) and chemical organic demand solubilization of heated sludge were investigated.Microwave heating was found to be a rapid and efficient process for releasing organic substrates from sludge.The increase of organic dissolution ratio was not obvious when holding time was over 5 min with microwave heating.The effect of the VSS solubilization was primarily dependent on heating temperature.The highest value of VSS dissolving ratio,36.4%,was obtained at 170°C for 30 min.The COD dissolving ratio was about 25% at 170°C.Total organic carbon of treated sludge liquor was 1.98 and 2.73 g/L at 150°C and 170°C for 5 min,respectively.A biochemical methane potential(BMP) test of excess sludge and a mixture of primary and excess sludge demonstrated an increase in biogas production.The total biogas from microwave treated mixture sludge increased by 12.9% to 20.2% over control after 30 days of digestion.Biogas production was 11.1% to 25.9% higher for excess sludge than for untreated sludge.The VS removal ratios of mixture sludge and excess sludge were 12% and 11% higher,respectively,compared to the untreated sludge.

  9. Changes in microbial community during hydrogen and methane production in two-stage thermophilic anaerobic co-digestion process from biowaste.

    Science.gov (United States)

    Zahedi, S; Solera, R; Micolucci, F; Cavinato, C; Bolzonella, D

    2016-03-01

    In this paper, the microbial community in a two-phase thermophilic anaerobic co-digestion process was investigated for its role in hydrogen and methane production, treating waste activated sludge and treating the organic fraction of municipal solid waste. In the acidogenic phase, in which hydrogen is produced, Clostridium sp. clusters represented 76% of total Firmicutes. When feeding the acidogenic effluent into the methanogenic reactors, these acidic conditions negatively influenced methanogenic microorganisms: Methanosaeta sp., (Methanobacteriales, Methanomicrobiales, Methanococcales) decreased by 75%, 50%, 38% and 52%, respectively. At the same time, methanogenic digestion lowered the numbers of Clostridium sp. clusters due to both pH increasing and substrate reduction, and an increase in both Firmicutes genera (non Clostridium) and methanogenic microorganisms, especially Methanosaeta sp. (208%). This was in accordance with the observed decrease in acetic (98%) and butyric (100%) acid contents. To ensure the activity of the acetate-utilizing methanogens (AUM) and the acetogens, high ratios of H2-utilizing methanogens (HUM)/AUM (3.6) were required.

  10. Microbial community dynamics in mesophilic anaerobic co-digestion of mixed waste.

    Science.gov (United States)

    Supaphol, Savaporn; Jenkins, Sasha N; Intomo, Pichamon; Waite, Ian S; O'Donnell, Anthony G

    2011-03-01

    This paper identifies key components of the microbial community involved in the mesophilic anaerobic co-digestion (AD) of mixed waste at Rayong Biogas Plant, Thailand. The AD process is separated into three stages: front end treatment (FET); feed holding tank and the main anaerobic digester. The study examines how the microbial community structure was affected by the different stages and found that seeding the waste at the beginning of the process (FET) resulted in community stability. Also, co-digestion of mixed waste supported different bacterial and methanogenic pathways. Typically, acetoclastic methanogenesis was the major pathway catalysed by Methanosaeta but hydrogenotrophs were also supported. Finally, the three-stage AD process means that hydrolysis and acidogenesis is initiated prior to entering the main digester which helps improve the bioconversion efficiency. This paper demonstrates that both resource availability (different waste streams) and environmental factors are key drivers of microbial community dynamics in mesophilic, anaerobic co-digestion.

  11. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

    Thermophilic anaerobic processes are often regarded as less stable than mesophilic processes. In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants. The start-up produce for the thermophilic plants was......, however, found to be crucial for determining the period needed before full capacity of the thermophilic plant could be achived. The importance of balanced loading, determined by the concentration of active biomass, is discussed. Finally, data will be shown on the optimal and maximal temperature...... for thermophilic digestion along with the implications for the methanogenic bacteria active at these temperatures....

  12. Anaerobic digestion of municipal solid waste: Technical developments

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States)

    1996-01-01

    The anaerobic biogasification of organic wastes generates two useful products: a medium-Btu fuel gas and a compost-quality organic residue. Although commercial-scale digestion systems are used to treat municipal sewage wastes, the disposal of solid organic wastes, including municipal solid wastes (MSW), requires a more cost-efficient process. Modern biogasification systems employ high-rate, high-solids fermentation methods to improve process efficiency and reduce capital costs. The design criteria and development stages are discussed. These systems are also compared with conventional low-solids fermentation technology.

  13. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

    El-Fadel, Mutasem E.

    2013-01-01

    Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and more recently as a greenhouse gas (GHG) mitigation measure. In this context, AD systems operating at thermophilic temperatures (55-60°C)-compared to mesophilic temperatures (35-40°C)-have the unique feature of producing hygienic soil conditioners with greater process efficiency, higher energy yield, and more GHG savings. Startup of AD systems is often constrained by the lack of acclimated seeds, leading to process instability and failure. The authors focus on strategies to startup thermophilic digesters treating OFMSW in the absence of acclimated seeds and examines constraints associated with process stability and ways to overcome them. Relevant gaps in the literature and future research needs are delineated. © 2013 Taylor & Francis Group, LLC.

  14. FUEL CELL OPERATION ON ANAEROBIC DIGESTER GAS: CONCEPTUAL DESIGN AND ASSESSMENT

    Science.gov (United States)

    The conceptual design of a fuel cell (FC) system for operation on anaerobic digester gas (ADG) is described and its economic and environmental feasibility is projected. ADG is produced at water treatment plants during the process of treating sewage anaerobically to reduce solids....

  15. Anaerobic digestion of olive oil mill effluents together with swine manure in UASB reactors

    DEFF Research Database (Denmark)

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

    2002-01-01

    Combined anaerobic digestion of olive oil mill effluent (OME) with swine manure, was investigated. In batch experiments was shown that for anaerobic degradation of OME alone nitrogen addition was needed. A COD:N ratio in the range of 65:1 to 126:1 was necessary for the optimal degradation process...

  16. 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...

  17. Environmental impact of rejected materials generated in organic fraction of municipal solid waste anaerobic digestion plants: Comparison of wet and dry process layout.

    Science.gov (United States)

    Colazo, Ana-Belén; Sánchez, Antoni; Font, Xavier; Colón, Joan

    2015-09-01

    Anaerobic digestion of source separated organic fraction of municipal solid waste is an increasing waste valorization alternative instead of incineration or landfilling of untreated biodegradable wastes. Nevertheless, a significant portion of biodegradable wastes entering the plant is lost in pre-treatments and post-treatments of anaerobic digestion facilities together with other improper materials such as plastics, paper, textile materials and metals. The rejected materials lost in these stages have two main implications: (i) less organic material enters to digesters and, as a consequence, there is a loss of biogas production and (ii) the rejected materials end up in landfills or incinerators contributing to environmental impacts such as global warming or eutrophication. The main goals of this study are (i) to estimate potential losses of biogas in the rejected solid materials generated during the pre- and post-treatments of two full-scale anaerobic digestion facilities and (ii) to evaluate the environmental burdens associated to the final disposal (landfill or incineration) of these rejected materials by means of Life Cycle Assessment. This study shows that there is a lost of potential biogas production, ranging from 8% to 15%, due to the loss of organic matter during pre-treatment stages in anaerobic digestion facilities. From an environmental point of view, the Life Cycle Assessment shows that the incineration scenario is the most favorable alternative for eight out of nine impact categories compared with the landfill scenario. The studied impact categories are Climate Change, Fossil depletion, Freshwater eutrophication, Marine eutrophication, Ozone depletion, Particulate matter formation, Photochemical oxidant formation, Terrestrial acidification and Water depletion.

  18. Anaerobic digestion of nitrophilic algal biomass from the Venice Lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Rigoni-Stern, S.; Rismondo, R. (Technital S.p.A., Verona (IT)); Szpyrkowicz, L.; Zilio-Grandi, F. (Venice Univ. (Italy)); Vigato, P.A. (Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi)

    1990-01-01

    The feasibility of producing biogas by anaerobic digestion of a nitrophilic algae biomass obtained from the highly eutrophicated Venice Lagoon has been investigated. Methods for harvesting algal biomass have been examined in detail and different pretreatments used prior to analysis and digestion of the algae described. Results obtained from three pilot plant digesters over a period of 12 months using Ulva rigida and Gracilaria as feed material gave no indication of inhibition of the process by either high salinity or high metals content resulting from pollutants discharged into the lagoon. Sulphides were formed during digestion as a consequence of the high sulphate content of the interstitial water as well as the level of sulphur present in the algae. However, the sulphides did not appear to cause inhibition or result in a reduction in gas yield. A maximum biogas production rate of 0.347 m{sup 3} kg VS{sup -1} day{sup -1} was obtained during digestion at a retention time of 20 days with an organic loading rate of 1 kg VS m{sup -3} day{sup -1}. (author).

  19. Anaerobic digestion of solid wastes of cane sugar industry

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, A.

    1983-01-01

    The cane sugar manufacturing industry generates large quantities of lignocellulosic solid wastes, namely bagasse and cachaza. Bagasse is the fibrous residue of the cane after extracting the juice. Cachaza is the filter cake of the precipitated insoluble sugars. This research investigates the feasibility of anaerobic digestion of a mixture of bagasse and cachaza to produce methane. Two rations of bagasse-cachaza mix as substrates were investigated. The first one was 8:1 which represents the average ratio of bagasse and cachaza produced in a raw sugar mill. The second ratio investigated was 2.4:1 which represents the proportion of bagasse and cachaza wastes after 70% of the bagasse is burned in sugar mill boilers. An acclimated microbial culture for this substrate was developed. Organic Loading-Detention Time relationships were established for an optimum system. Pre-treatment techniques of the substrate were investigated as a means of enhancing the digestibility of the cellulosic substrate. Recirculation of the filtrate was evaluated as a method for increasing solids retention time without increasing hydraulic detention time. The kinetics of the digestion process for bagasse-cachaza mixed substrate was investigated and growth constants were determined. The bionutritional characteristics of the substrate used for the digestion were evaluated. Based on the results obtained, mass balances and preliminary economic analysis of the digestion system were developed.

  20. Thermophilic anaerobic digestion versus mesophilic anaerobic digestion of sludges from WTP; Digestion anaerobic termofilica versus digestion anaerobia mesofilica de lodos del EDAR

    Energy Technology Data Exchange (ETDEWEB)

    Rubia de la Romero, M. A.; Perez Garcia, M.; Romero Garcia, L. I.; Sales Marquez, D.

    2001-07-01

    A literature search revealed that successful thermophilic digestion operation was achieved at several Sewage Treatment Plant: Hyperon Treatment Plant of the city of Los Angeles, operations at 49 degree centigree resulted in significant improvements in sludge handling characteristics; West-Southwest Sewage Treatment Works, Chicago, Illinois a stable thermophilic digester was established at a 8 day detention time; Lions Gate Wastewater Treatment Plant of Vancouver pathogen destruction was the primary goal of this evaluation. Several other investigators have also conducted laboratory as well as pilot scale studied and reported several potential advantages of operating anaerobic digesters in the thermophilic range, rather than the conventional mesophilic range. Increased destruction of pathogenic organisms, increased rate of volatile solids destruction and improved destruction of organics are some advantages reported by all authors. (Author) 16 refs.

  1. Industrial symbiosis: corn ethanol fermentation, hydrothermal carbonization, and anaerobic digestion.

    Science.gov (United States)

    Wood, Brandon M; Jader, Lindsey R; Schendel, Frederick J; Hahn, Nicholas J; Valentas, Kenneth J; McNamara, Patrick J; Novak, Paige M; Heilmann, Steven M

    2013-10-01

    The production of dry-grind corn ethanol results in the generation of intermediate products, thin and whole stillage, which require energy-intensive downstream processing for conversion into commercial animal feed products. Hydrothermal carbonization of thin and whole stillage coupled with anaerobic digestion was investigated as alternative processing methods that could benefit the industry. By substantially eliminating evaporation of water, reductions in downstream energy consumption from 65% to 73% were achieved while generating hydrochar, fatty acids, treated process water, and biogas co-products providing new opportunities for the industry. Processing whole stillage in this manner produced the four co-products, eliminated centrifugation and evaporation, and substantially reduced drying. With thin stillage, all four co-products were again produced, as well as a high quality animal feed. Anaerobic digestion of the aqueous product stream from the hydrothermal carbonization of thin stillage reduced chemical oxygen demand (COD) by more than 90% and converted 83% of the initial COD to methane. Internal use of this biogas could entirely fuel the HTC process and reduce overall natural gas usage.

  2. Hygienization of sludge through anaerobic digestion at 35, 55 and 60 °C.

    Science.gov (United States)

    Kjerstadius, H; la Cour Jansen, J; De Vrieze, J; Haghighatafshar, S; Davidsson, A

    2013-01-01

    Legislation in Sweden and the European Union concerning the use of sewage sludge in agriculture is under revision and future concentration limits for pathogens in treated sludge are likely to be expected. The aim of this study was to evaluate the hygienization of Salmonella, Escherichia coli, Enterococcus and Clostridium perfringens through continuous anaerobic digestion at 35, 55 or 60 °C, as well as to investigate process stability and methane production at 60 °C. The results indicated that digestion at 55 or 60 °C with a minimum exposure time of 2 h resulted in good reduction of Salmonella, E. coli and Enterococcus and that anaerobic digestion could thus be used to reach the concentration limits suggested for the EU, as well as Sweden. Furthermore, stable continuous anaerobic digestion of sludge was achieved at 60 °C, albeit with 10% less methane production compared to digestion at 35 and 55 °C.

  3. Microbiology of anaerobic digestion; Microbiologia da digestao anaerobica

    Energy Technology Data Exchange (ETDEWEB)

    Novaes, Rosana Filomena Vazoller [CETESB, Sao Paulo, SP (Brazil)

    1988-12-31

    Considerations was made about the microorganisms involved in the anaerobic digestion of wastes. Are also presented, the main results on this subject obtained, until now, in the studies carried on the group of anaerobic microbiology researchers from the Sanitary Company of Sao Paulo State, Brazil. (author) 23 refs., 8 figs., 3 tabs.

  4. Using contaminated plants involved in phytoremediation for anaerobic digestion.

    Science.gov (United States)

    Cao, Zewei; Wang, Shengxiao; Wang, Ting; Chang, Zhizhou; Shen, Zhenguo; Chen, Yahua

    2015-01-01

    This study investigated the anaerobic digestion capability of five plants and the effects of copper (Cu) and S,S'-ethylenediaminedisuccinic acid (EDDS, a chelator widely used in chelant-assisted phytoremediation) on biogas production to determine a feasible disposal method for plants used in remediation. The results showed that in addition to Phytolacca americana L., plants such as Zea mays L., Brassica napus L., Elsholtzia splendens Nakai ex F. Maekawa, and Oenothera biennis L. performed well in biogas production. Among these, O. biennis required the shortest period to finish anaerobic digestion. Compared to normal plants with low Cu content, the plants used in remediation with increased Cu levels (100 mg kg(-1)) not only promoted anaerobic digestion and required a shorter anaerobic digestion time, but also increased the methane content in biogas. When the Cu content in plants increased to 500, 1000, and 5000 mg kg(-1), the cumulative biogas production decreased by 12.3%, 14.6%, and 41.2%, respectively. Studies also found that EDDS conspicuously restrained biogas production from anaerobic digestion. The results suggest that anaerobic digestion has great potential for the disposal of contaminated plants and may provide a solution for the resource utilization of plants used in remediation.

  5. Thermal pretreatment of algae for anaerobic digestion.

    Science.gov (United States)

    Marsolek, Michael D; Kendall, Elizabeth; Thompson, Phillip L; Shuman, Teodora Rutar

    2014-01-01

    The objective of this work was to determine the benefit of thermal pretreatment on biogas yield from microalgae-fed anaerobic digester mesocosms. Replicate Nanochloropsis oculata cultures were heated for 4h at 30, 60, and 90°C, as well as at a constant temperature of 90°C for 1, 3.5, and 12h. Net biogas production increased from 0.28L biogas/g volatile solids added (VSa) for the control to 0.39 L biogas/g VSa (p<0.01) when heated at 90°C, but there was no improvement at 30 or 60°C. Increased biogas production correlated with increased soluble chemical oxygen demand (COD). Net biogas production increased as a function of heating time, from 0.32 L biogas/g VSa for the control, to 0.41, 0.43, and 0.44 L biogas/g VSa (p<0.05 for all combinations vs. control) when preheated at 90°C for 1, 3.5, and 12h, respectively. However, despite enhanced biogas production the energy balance is negative for thermal pretreatment.

  6. Steam-explosion pretreatment for enhancing anaerobic digestion of municipal wastewater sludge.

    Science.gov (United States)

    Dereix, Marcela; Parker, Wayne; Kennedy, Kevin

    2006-05-01

    This study evaluated the use of steam explosion as a pretreatment for municipal wastewater treatment sludges and biosolids as a technique for enhancing biogas generation during anaerobic digestion. Samples of dewatered anaerobic digester effluent (biosolids) and a mixture of thickened waste activated sludge (TWAS) and biosolids were steam-exploded under differing levels of intensity in this study. The results indicate that steam explosion can solublize components of these sludge streams. Increasing the intensity of the steam-explosion pressure and temperature resulted in increased solublization. The steam-explosion pretreatment also increased the bioavailability of sludge components under anaerobic digestion conditions. Increasing the steam-explosion intensity increased the ultimate yield of methane during anaerobic digestion. Batch anaerobic digestion tests suggested that pretreatment at 300 psi was the most optimal condition for enhanced biogas generation while minimizing energy input. Semicontinuous anaerobic digestion revealed that the results that were observed in the batch tests were sustainable in prolonged operation. Semicontinuous digestion of the TWAS/biosolids mixture that was pretreated at 300 psi generated approximately 50% more biogas than the controls. Semicontinuous digestion of the pretreated biosolids resulted in a 3-fold increase in biogas compared with the controls. Based on capillary suction test results, steam-explosion pretreatment at 300 psi improved the dewaterability of the final digested sludge by 32 and 45% for the TWAS/ biosolids mixture and biosolids, respectively, compared with controls. The energy requirements of the nonoptimized steam-explosion process were substantially higher than the additional energy produced from enhanced digestion of the pretreated sludge. Substantial improvements in energy efficiency will be required to make the process viable from an energy perspective.

  7. 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.

  8. Removal of polycyclic aromatic hydrocarbons (PAH) during anaerobic digestion with recirculation of ozonated digested sludge

    Energy Technology Data Exchange (ETDEWEB)

    Bernal-Martinez, Arodi; Patureau, Dominique; Delgenes, Jean-Philippe [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F11100 (France); Carrere, Helene [INRA, UR 050, Laboratoire de Biotechnologie de l' Environnement, Avenue des Etangs, Narbonne F11100 (France)], E-mail: carrere@supagro.inra.fr

    2009-03-15

    PAH are particularly monitored because of their carcinogenic properties and their ubiquity in the environment. Their presence in municipal sewage sludge is a major problem due to the environmental risks associated with the sludge spreading on agricultural soils. The objective of this work was to asses the removal of PAH naturally present in sludge by continuous anaerobic digestion with recirculation of ozonated sludge. Recirculation of ozonated digested sludge allowed to enhance PAH removals, the highest efficiency was obtained with the highest ozone dose (0.11 g O{sub 3}/g{sub TS}). In order to study the effect of recirculation, a reactor was operated without recirculation but was fed with a mixture of raw and ozonated digested sludge. This process led to the best performances in terms of PAH and solid removals. This pointed out some accumulation of nonbiodegradable or recalcitrant compounds during recirculation assay. Smallest and most soluble compounds presented the highest biodegradation efficiencies.

  9. Modelling of the mesophilic anaerobic co-digestion of olive mill wastewater with olive mill solid waste using anaerobic digestion model No. 1 (ADM1).

    Science.gov (United States)

    Boubaker, Fezzani; Ridha, Ben Cheikh

    2008-09-01

    The anaerobic digestion model No. 1 (ADM1), conceived by the international water association (IWA) task group for mathematical modelling of anaerobic digestion processes is a structured generic model which includes multiples steps describing biochemical and physicochemical processes encountered in the anaerobic degradation of complex organic substrates and a common platform for further model enhancement and validation of dynamic simulations for a variety of anaerobic processes. In this study the ADM1 model was modified and applied to simulate the mesophilic anaerobic co-digestion of olive mill wastewater (OMW) with olive mill solid waste (OMSW). The ADM1 equations were coded and implemented using the simulation software package MATLAB/Simulink. The most sensitive parameters were calibrated and validated using updated experimental data of our previous work. The results indicated that the ADM1 model could simulate with good accuracy: gas flows, methane and carbon-dioxide contents, pH and total volatile fatty acids (TVFA) concentrations of effluents for various feed concentrations digested at different hydraulic retention times (HRTs) and especially at HRTs of 36 and 24 days. Furthermore, effluent alkalinity and ammonium nitrogen were successfully predicted by the model at HRTs of 12 and 24 days for some feed concentrations.

  10. Optimisation and inhibition of anaerobic digestion of livestock manure

    Energy Technology Data Exchange (ETDEWEB)

    Sutaryo, S.

    2012-11-15

    The optimisation process during this PhD study focused on mixed enzyme (ME) addition, thermal pre-treatment and co-digestion of raw manure with solid fractions of acidified manure, while for inhibition processes, ammonia and sulphide inhibition were studied. ME addition increased methane yield of both dairy cow manure (DCM) and solid fractions of DCM (by 4.44% and 4.15% respectively, compared to the control) when ME was added to manure and incubated prior to anaerobic digestion (AD). However, no positive effect was found when ME was added to manure and fed immediately to either mesophilic (35 deg. C) or thermophilic (50 deg. C) digesters. Low-temperature pre-treatment (65 deg. C to 80 deg. C for 20 h) followed by batch assays increased the methane yield of pig manure in the range from 9.5% to 26.4% at 11 d incubation. These treatments also increased the methane yield of solid-fractions pig manure in the range from 6.1% to 25.3% at 11 d of the digestion test. However, at 90 d the increase in methane yield of pig manure was only significant at the 65 deg. C treatment, thus low-temperature thermal pre-treatment increased the rate of gas production, but did not increase the ultimate yield (B{sub o}). High-temperature pre-treatment (100 deg. C to 225 deg. C for 15 min.) increased the methane yield of DCM by 13% and 21% for treatments at 175 deg. C and 200 deg. C, respectively, at 27 d of batch assays. For pig manure, methane yield was increased by 29% following 200 deg. C treatment and 27 d of a batch digestion test. No positive effect was found of high-temperature pre-treatment on the methane yield of chicken manure. At the end of the experiment (90 d), high-temperature thermal pre-treatment was significantly increasing the B{sub 0} of pig manure and DCM. Acidification of animal manure using sulphuric acid is a well-known technology to reduce ammonia emission of animal manure. AD of acidified manure showed sulphide inhibition and consequently methane production was 45

  11. Anaerobic digestion technology in livestock manure treatment for biogas production: a review

    Energy Technology Data Exchange (ETDEWEB)

    Nasir, Ismail M. [Department of Chemical and Environmental Engineering, Faculty of Engineering, Universiti Putra Malaysia, Selangor (Malaysia); Mohd Ghazi, Tinia I.; Omar, Rozita

    2012-06-15

    This article reviews the potential of anaerobic digestion (AD) for biogas production from livestock manure wastes and compares the operating and performance data for various anaerobic process configurations. It examines different kinds of manure waste treatment techniques and the influence of several parameters on biogas and methane yield. The comparison indicates that a variety of different operational conditions, various reactor configurations such as batch reactors, continuously stirred tank reactor (CSTR), plug flow reactor (PFR), up-flow anaerobic sludge blanket (UASB), anaerobic sequencing batch reactor (ASBR), temperature phased anaerobic digestion (TPAD), and continuous one- and two-stage systems, present a suitable technology for the AD of livestock manure waste. Main performance indicators are biogas and methane yield, degradation of volatile solids (VS), higher loading, and process stability with a short retention time. (copyright 2012 WILEY-VCH Verlag GmbH 8 Co. KGaA, Weinheim)

  12. Anaerobic digestion of selected Italian agricultural and industrial residues (grape seeds and leather dust): combined methane production and digestate characterization.

    Science.gov (United States)

    Caramiello, C; Lancellotti, I; Righi, F; Tatàno, F; Taurino, R; Barbieri, L

    2013-01-01

    A combined experimental evaluation of methane production (obtained by anaerobic digestion) and detailed digestate characterization (with physical-chemical, thermo-gravimetric and mineralogical approaches) was conducted on two organic substrates, which are specific to Italy (at regional and national levels). One of the substrates was grape seeds, which have an agricultural origin, whereas the other substrate was vegetable-tanned leather dust, which has an industrial origin. Under the assumed experimental conditions of the performed lab-scale test series, the grape seed substrate exhibited a resulting net methane production of 175.0 NmL g volatile solids (VS)(-1); hence, it can be considered as a potential energy source via anaerobic digestion. Conversely, the net methane production obtained from the anaerobic digestion of the vegetable-tanned leather dust substrate was limited to 16.1 NmL gVS(-1). A detailed characterization of the obtained digestates showed that there were both nitrogen-containing compounds and complex organic compounds present in the digestate that was obtained from the mixture of leather dust and inoculum. As a general perspective of this experimental study, the application of diversified characterization analyzes could facilitate (1) a better understanding of the main properties of the obtained digestates to evaluate their potential valorization, and (2) a combination of the digestate characteristics with the corresponding methane productions to comprehensively evaluate the bioconversion process.

  13. Trace metal speciation and bioavailability in anaerobic digestion: A review.

    Science.gov (United States)

    Thanh, Pham Minh; Ketheesan, Balachandran; Yan, Zhou; Stuckey, David

    2016-01-01

    Trace metals are essential for the growth of anaerobic microorganisms, however, in practice they are often added to anaerobic digesters in excessive amounts, which can lead to inhibition. The concept of bioavailability of metals in anaerobic digestion has been poorly understood in the past, and a lack of deep understanding of the relationship between trace metal speciation and bioavailability can result in ineffective metal dosing strategies for anaerobic digesters. Sequential extraction schemes are useful for fractionating trace metals into their different forms, and metal sulfides can serve as a store and source for trace metals during anaerobic digestion, while natural/synthetic chelating agents (soluble microbial products-SMPs, extracellular polysaccharides-EPS, and EDTA/NTA) are capable of controlling trace metal bioavailability. Nevertheless, more work is needed to: investigate the speciation and bioavailability of Ca, Mg, Mn, W, and Se; compare the bioavailability of different forms of trace metals e.g. carbonates, sulfides, phosphates to different anaerobic trophic groups; determine what factors influence metal sulfide dissolution; investigate whether chelating agents can increase trace metal bioavailability; develop and adapt specialized analytical techniques, and; determine how trace metal dynamics change in an anaerobic membrane bioreactor (AnMBR).

  14. 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.

  15. Optimisation of the two-phase dry-thermophilic anaerobic digestion process of sulphate-containing municipal solid waste: population dynamics.

    Science.gov (United States)

    Zahedi, S; Sales, D; Romero, L I; Solera, R

    2013-11-01

    Microbial population dynamics and anaerobic digestion (AD) process to eight different hydraulic retention times (HRTs) (from 25d to 3.5d) in two-phase dry-thermophilic AD from sulphate-containing solid waste were investigated. Maximum values of gas production (1.9 ± 0.2 l H2/l/d; 5.4 ± 0.3 l CH4/l/d and 82 ± 9 ml H2S/l/d) and microbial activities were obtained at 4.5d HRT; where basically comprised hydrolysis step in the first phase (HRT=1.5d) and acidogenic step finished in the second phase as well as acetogenic-methanogenic steps (HRT=3d). In the first phase, hydrolytic-acidogenic bacteria (HABs) was the main group (44-77%) and Archaea, acetogens and sulphate-reducing bacteria (SRBs) contents were not significant; in the second phase (except to 2d HRT), microbial population was able to adapt to change in substrate and HRTs to ensure the proper functioning of the system and both acetogens and Archaea were dominated over SRBs. Decreasing HRT resulted in an increase in microbial activities.

  16. Mesophilic batch anaerobic co-digestion of fruit-juice industrial waste and municipal waste sludge: process and cost-benefit analysis.

    Science.gov (United States)

    Hosseini Koupaie, E; Barrantes Leiva, M; Eskicioglu, C; Dutil, C

    2014-01-01

    The feasibility of anaerobic co-digestion of two juice-based beverage industrial wastes, screen cake (SC) and thickened waste activated sludge (TWAS), along with municipal sludge cake (MC) was investigated. Experiments were conducted in twenty mesophilic batch 160 ml serum bottles with no inhibition occurred. The statistical analysis proved that the substrate type had statistically significant effect on both ultimate biogas and methane yields (P=0.0003<0.05). The maximum and minimum ultimate cumulative methane yields were 890.90 and 308.34 mL/g-VSremoved from the digesters containing only TWAS and SC as substrate. First-order reaction model well described VS utilization in all digesters. The first 2-day and 10-day specific biodegradation rate constants were statistically higher in the digesters containing SC (P=0.004<0.05) and MC (P=0.0005<0.05), respectively. The cost-benefit analysis showed that the capital, operating and total costs can be decreased by 21.5%, 29.8% and 27.6%, respectively using a co-digester rather than two separate digesters.

  17. Investigation of Poultry Waste for Anaerobic Digestion: A Case Study

    Science.gov (United States)

    Salam, Christopher R.

    Anaerobic Digestion (AD) is a biological conversion technology which is being used to produce bioenergy all over the world. This energy is created from biological feedstocks, and can often use waste products from various food and agricultural processors. Biogas from AD can be used as a fuel for heating or for co-generation of electricity and heat and is a renewable substitute to using fossil fuels. Nutrient recycling and waste reduction are additional benefits, creating a final product that can be used as a fertilizer in addition to energy benefits. This project was conducted to investigate the viability of three turkey production wastes as AD feedstock: two turkey litters and a material separated from the turkey processing wastewater using dissolved air flotation (DAF) process. The DAF waste contained greases, oils and other non-commodity portions of the turkey. Using a variety of different process methods, types of bacteria, loading rates and food-to-microorganism ratios, optimal loading rates for the digestion of these three materials were obtained. In addition, the co-digestion of these materials revealed additional energy benefits. In this study, batch digestion tests were carried out to treat these three feedstocks, using mesophilic and thermophilic bacteria, using loading rates of 3 and 6 gVS/L They were tested separately and also as a mixture for co-digestion. The batch reactor used in this study had total and working volumes of 1130 mL and 500 mL, respectively. The initial organic loading was set to be 3 gVS/L, and the food to microorganism ratio was either 0.6 or 1.0 for different treatments based on the characteristics of each material. Only thermophilic (50 +/- 2ºC) temperatures were tested for the litter and DAF wastes in continuous digestion, but mesophilic and thermophilic batch digestion experiments were conducted. The optimum digestion time for all experiments was 14 days. The biogas yields of top litter, mixed litter, and DAF waste under

  18. University of Wisconsin Oshkosh Anaerobic Dry Digestion Facility

    Energy Technology Data Exchange (ETDEWEB)

    Koker, John [Univ. of Wisconsin, Oshkosh, WI (United States); Lizotte, Michael [Univ. of Wisconsin, Oshkosh, WI (United States)

    2017-02-08

    The University of Wisconsin Oshkosh Anaerobic Dry Digestion Facility is a demonstration project that supported the first commercial-scale use in the United States of high solids, static pile technology for anaerobic digestion of organic waste to generate biogas for use in generating electricity and heat. The research adds to the understanding of startup, operation and supply chain issues for anaerobic digester technology. Issues and performance were documented for equipment installation and modifications, feedstock availability and quality, weekly loading and unloading of digestion chambers, chemical composition of biogas produced, and energy production. This facility also demonstrated an urban industrial ecology approach to siting such facilities near sewage treatment plants (to capture and use excess biogas generated by the plants) and organic yard waste collection sites (a source of feedstock).

  19. Performance assessment of two-stage anaerobic digestion of kitchen wastes.

    Science.gov (United States)

    Bo, Zhang; Pin-Jing, He

    2014-01-01

    This study is aimed at investigating the performance of the two-phase anaerobic digestion of kitchen wastes in a lab-scale setup. The semi-continuous experiment showed that the two-phase anaerobic digestion of kitchen wastes had a bioconversion rate of 83%, biogas yield of 338 mL x (g chemical oxygen demand (COD))(-1) and total solid conversion of 63% when the entire two-phase anaerobic digestion process was subjected to an organic loading rate (OLR) of 10.7 g x (L d)(-1). In the hydrolysis-acidogenesis process, the efficiency of solubilization decreased from 72.6% to 41.1%, and the acidogenesis efficiency decreased from 31.8% to 17.8% with an increase in the COD loading rate. On the other hand, the performance of the subsequent methanogenic process was not susceptible to the increase in the feeding COD loading rate in the hydrolysis-acidogenesis stage. Lactic acid was one of the main fermentation products, accounting for over 40% of the total soluble COD in the fermentation liquid. The batch experiments indicated that the lactic acid was the earliest predominant fermentation product, and distributions of fermentation products were pH dependent. Results showed that increasing the feeding OLR of kitchen wastes made the two-stage anaerobic digestion process more effective. Moreover, there was a potential improvement in the performance of anaerobic digestion of kitchen wastes with a corresponding improvement in the hydrolysis process.

  20. Engineering Digestion: Multiscale Processes of Food Digestion.

    Science.gov (United States)

    Bornhorst, Gail M; Gouseti, Ourania; Wickham, Martin S J; Bakalis, Serafim

    2016-03-01

    Food digestion is a complex, multiscale process that has recently become of interest to the food industry due to the developing links between food and health or disease. Food digestion can be studied by using either in vitro or in vivo models, each having certain advantages or disadvantages. The recent interest in food digestion has resulted in a large number of studies in this area, yet few have provided an in-depth, quantitative description of digestion processes. To provide a framework to develop these quantitative comparisons, a summary is given here between digestion processes and parallel unit operations in the food and chemical industry. Characterization parameters and phenomena are suggested for each step of digestion. In addition to the quantitative characterization of digestion processes, the multiscale aspect of digestion must also be considered. In both food systems and the gastrointestinal tract, multiple length scales are involved in food breakdown, mixing, absorption. These different length scales influence digestion processes independently as well as through interrelated mechanisms. To facilitate optimized development of functional food products, a multiscale, engineering approach may be taken to describe food digestion processes. A framework for this approach is described in this review, as well as examples that demonstrate the importance of process characterization as well as the multiple, interrelated length scales in the digestion process.

  1. State estimation for anaerobic digesters using the ADM1.

    Science.gov (United States)

    Gaida, D; Wolf, C; Meyer, C; Stuhlsatz, A; Lippel, J; Bäck, T; Bongards, M; McLoone, S

    2012-01-01

    The optimization of full-scale biogas plant operation is of great importance to make biomass a competitive source of renewable energy. The implementation of innovative control and optimization algorithms, such as Nonlinear Model Predictive Control, requires an online estimation of operating states of biogas plants. This state estimation allows for optimal control and operating decisions according to the actual state of a plant. In this paper such a state estimator is developed using a calibrated simulation model of a full-scale biogas plant, which is based on the Anaerobic Digestion Model No.1. The use of advanced pattern recognition methods shows that model states can be predicted from basic online measurements such as biogas production, CH4 and CO2 content in the biogas, pH value and substrate feed volume of known substrates. The machine learning methods used are trained and evaluated using synthetic data created with the biogas plant model simulating over a wide range of possible plant operating regions. Results show that the operating state vector of the modelled anaerobic digestion process can be predicted with an overall accuracy of about 90%. This facilitates the application of state-based optimization and control algorithms on full-scale biogas plants and therefore fosters the production of eco-friendly energy from biomass.

  2. Mesophilic and thermophilic anaerobic co-digestion of abattoir wastewater and fruit and vegetable waste in anaerobic sequencing batch reactors.

    Science.gov (United States)

    Bouallagui, Hassib; Rachdi, Boutheina; Gannoun, Hana; Hamdi, Moktar

    2009-06-01

    Anaerobic co-digestion of fruit and vegetable waste (FVW) and abattoir wastewater (AW) was investigated using anaerobic sequencing batch reactors (ASBRs). The effects of hydraulic retention time (HRT) and temperature variations on digesters performances were examined. At both 20 and 10 days biogas production for co-digestion was greater thanks to the improved balance of nutrients. The high specific gas productions for the different digestion processes were 0.56, 0.61 and 0.85 l g(-1) total volatile solids (TVS) removal for digesters treating AW, FVW and AW + FVW, respectively. At an HRT of 20 days, biogas production rates from thermophilic digesters were higher on average than from mesophilic AW, FVW and AW + FVW digestion by 28.5, 44.5 and 25%, respectively. However, at 10 days of HRT results showed a decrease of biogas production rate for AW and AW + FVW digestion processes due to the high amount of free ammonia at high organic loading rate (OLR).

  3. Ammonia and temperature determine potential clustering in the anaerobic digestion microbiome.

    Science.gov (United States)

    De Vrieze, Jo; Saunders, Aaron Marc; He, Ying; Fang, Jing; Nielsen, Per Halkjaer; Verstraete, Willy; Boon, Nico

    2015-05-15

    Anaerobic digestion is regarded as a key environmental technology in the present and future bio-based economy. The microbial community completing the anaerobic digestion process is considered complex, and several attempts already have been carried out to determine the key microbial populations. However, the key differences in the anaerobic digestion microbiomes, and the environmental/process parameters that drive these differences, remain poorly understood. In this research, we hypothesized that differences in operational parameters lead to a particular composition and organization of microbial communities in full-scale installations. A total of 38 samples were collected from 29 different full-scale anaerobic digestion installations, showing constant biogas production in function of time. Microbial community analysis was carried out by means of amplicon sequencing and real-time PCR. The bacterial community in all samples was dominated by representatives of the Firmicutes, Bacteroidetes and Proteobacteria, covering 86.1 ± 10.7% of the total bacterial community. Acetoclastic methanogenesis was dominated by Methanosaetaceae, yet, only the hydrogenotrophic Methanobacteriales correlated with biogas production, confirming their importance in high-rate anaerobic digestion systems. In-depth analysis of operational and environmental parameters and bacterial community structure indicated the presence of three potential clusters in anaerobic digestion. These clusters were determined by total ammonia concentration, free ammonia concentration and temperature, and characterized by an increased relative abundance of Bacteroidales, Clostridiales and Lactobacillales, respectively. None of the methanogenic populations, however, could be significantly attributed to any of the three clusters. Nonetheless, further experimental research will be required to validate the existence of these different clusters, and to which extent the presence of these clusters relates to stable or sub

  4. Anaerobic digestion of bio-waste: A mini-review focusing on territorial and environmental aspects.

    Science.gov (United States)

    Cecchi, Franco; Cavinato, Cristina

    2015-05-01

    Scientific and industrial experiences, together with economical and policies changes of last 30 years, bring anaerobic digestion among the most environmental friendly and economically advantageous technologies for organic waste treatment and management in Europe. In this short review, the role of anaerobic digestion of organic wastes is discussed, considering the opportunity of a territorial friendly approach, without barriers, where different organic wastes are co-treated. This objective can be achieved through two proposed strategies: one is the anaerobic digestion applied as a service for the agricultural and farming sector; the other as a service for citizen (biowaste, diapers and wastewater treatment integration). The union of these two strategies is an environmental- and territorial-friendly process that aims to produce renewable energy and fertiliser material, with a low greenhouse gas emission and nutrients recovery. The advantage of forthcoming application of anaerobic digestion of organic wastes, even for added value bioproducts production and new energy carriers, are finally discussed. Among several advantages of anaerobic digestion, the role of the environmental controller was evaluated, considering the ability of minimising the impacts exploiting the biochemical equilibrium and sensitivity as a quality assurance for digestate.

  5. Dry anaerobic digestion of lignocellulosic and protein residues

    Directory of Open Access Journals (Sweden)

    Maryam M Kabir

    2015-12-01

    Full Text Available Utilisation of wheat straw and wool textile waste in dry anaerobic digestion (AD process was investigated. Dry-AD of the individual substrates as well as co-digestion of those were evaluated using different total solid (TS contents ranging between 6 to 30%. Additionally, the effects of the addition of nutrients and cellulose- or protein-degrading enzymes on the performance of the AD process were also investigated. Dry-AD of the wheat straw resulted in methane yields of 0.081 – 0.200 Nm3CH4/kgVS with the lowest and highest values obtained at 30 and 21% TS, respectively. The addition of the cellulolytic enzymes could significantly increase the yield in the reactor containing 13% TS (0.231 Nm3CH4/kg VS. Likewise, degradation of wool textile waste was enhanced significantly at TS of 13% with the addition of the protein-degrading enzyme (0.131 Nm3CH4/kg VS. Furthermore, the co-digestion of these two substrates showed higher methane yields compared with the methane potentials calculated for the individual fractions at all the investigated TS contents due to synergetic effects and better nutritional balance.

  6. Testing low cost anaerobic digestion (AD) systems

    Science.gov (United States)

    To evaluate the potential for low technology and low cost digesters for small dairies, BARC and researchers from the University of Maryland installed six modified Taiwanese-model field-scale (FS) digesters near the original dairy manure digester. The FS units receive the same post-separated liquid ...

  7. Influence of lactic acid on the two-phase anaerobic digestion of kitchen wastes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bo; CAI Wei-min; HE Pin-jing

    2007-01-01

    To evaluate the influence of lactic acid on the methanogenesis, anaerobic digestion of kitchen wastes was firstly conducted in a two-phase anaerobic digestion process, and performance of two digesters fed with lactic acid and glucose was subsequently compared.The results showed that the lactic acid was the main fermentation products of hydrolysis-acidification stage in the two-phase anaerobic digestion process for kitchen wastes. The lactic acid concentration constituted approximately 50% of the chemical oxygen demand (COD) concentration in the hydrolysis-acidification liquid. The maximum organic loading rate was lower in the digester fed with lactic acid than that fed with glucose. Volatile fatty acids (VFAs) and COD removal were deteriorated in the methanogenic reactor fed with to the high concentration of lactic acid fed. It could be concluded that avoiding the presence of the lactic acid is necessary in the hydrolysis-acidification process for the improvement of the two-phase anaerobic digestion process of kitchen wastes.

  8. Anaerobic co-digestion of the marine microalga Nannochloropsis salina with energy crops.

    Science.gov (United States)

    Schwede, Sebastian; Kowalczyk, Alexandra; Gerber, Mandy; Span, Roland

    2013-11-01

    Anaerobic co-digestion of corn silage with the marine microalga Nannochloropsis salina was investigated under batch and semi-continuous conditions. Under batch conditions process stability and biogas yields significantly increased by microalgae addition. During semi-continuous long-term experiments anaerobic digestion was stable in corn silage mono- and co-digestion with the algal biomass for more than 200 days. At higher organic loading rates (4.7 kg volatile solids m(-3)d(-1)) inhibition and finally process failure occurred in corn silage mono-digestion, whereas acid and methane formation remained balanced in co-digestion. The positive influences in co-digestion can be attributed to an adjusted carbon to nitrogen ratio, enhanced alkalinity, essential trace elements and a balanced nutrient composition. The results suggest that N. salina biomass is a suitable feedstock for anaerobic co-digestion of energy crops, especially for regions with manure scarcity. Enhanced process stability may result in higher organic loading rates or lower digester volumes.

  9. Anaerobic digestion of pig farm sewage; Digestion Anaerobia de aguas residuales de granjas porcicolas

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez Borges, E.; Mendez Novelo, R.; Magana Pietra, A. [Universidad Autonoma de Yucatan. Departamento de Ingenieria Ambiental, Yucatan, Mexico (Mexico)

    1997-04-01

    The 534 litre anaerobic digester, composed of a UASB reactor at the bottom and a high-rate sedimentator at the top, was fed with pig and ruminants sewage. The formation of volatile fatty acids (VFA) was monitored as VFA concentration is usually decisive in controlling fermentation during the non-methanogenic stage. The results obtained with different retention times show the presence of different VFA concentrations, the highest concentration corresponding to a retention time of one day. The process was also found to be extremely elastic. (Author) 12 refs.

  10. Evaluation of the methanogenic step of a two-stage anaerobic digestion process of acidified olive mill solid residue from a previous hydrolytic-acidogenic step.

    Science.gov (United States)

    Rincón, B; Borja, R; Martín, M A; Martín, A

    2009-09-01

    A study of the second step or methanogenic stage of a two-stage anaerobic digestion process treating two-phase olive oil mill solid residue (OMSR) was conducted at mesophilic temperature (35 degrees C). The substrate fed to the methanogenic step was the effluent from a hydrolytic-acidogenic reactor operating at an organic loading rate (OLR) of 12.9 g chemical oxygen demand (COD) L(-1) d(-1) and at a hydraulic retention time (HRT) of 12.4 days; these OLR and HRT were found to be the best values to achieve the maximum total volatile fatty acid concentration (14.5 g L(-1) expressed as acetic acid) with a high concentration in acetic acid (57.5% of the total concentration) as the principal precursor of methane. The methanogenic stage was carried out in an anaerobic stirred tank reactor containing saponite as support media for the immobilization of microorganisms. OLRs of between 0.8 and 22.0 g COD L(-1) d(-1) were studied. These OLRs corresponded to HRTs of between 142.9 and 4.6 days. The methanogenic reactor operated with high stability for OLRs lower than 20.0 g COD L(-1) d(-1). This behaviour was shown by the total volatile fatty acids/total alkalinity ratio, whose values were always kept 0.12 for HRTs>4.6 days. The total COD (T-COD) removed was in the range of 94.3-61.3% and the volatile solids (VS) removed between 92.8% and 56.1% for OLRs between 0.8 and 20.0 g COD L(-1) d(-1). In the same way, a reduction of 43.8% was achieved for phenolic content. The low concentration of total volatile fatty acids (TVFA) observed (below 1 g L(-1) expressed as CH(3)COOH) in the methanogenic reactor effluents showed the high percentage of consumption and conversion of these acids to methane. A methane yield of 0.268+/-0.003 L CH(4) at standard temperature and pressure conditions (STP) g(-1) COD eliminated was achieved.

  11. 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%.

  12. Rate determination of supercritical water gasification of primary sewage sludge as a replacement for anaerobic digestion.

    Science.gov (United States)

    Wilkinson, Nikolas; Wickramathilaka, Malithi; Hendry, Doug; Miller, Andrew; Espanani, Reza; Jacoby, William

    2012-11-01

    Supercritical water gasification of primary sewage sludge sampled from a local facility was undertaken at different solids content. The performance of the process was compared with the anaerobic digestion system in use at the facility where the samples were taken. The mass and composition of the vapor products documented showed that the process generates more energy per gram of feed while rapidly destroying more volatile solids relative to the anaerobic digestion process. However, the energy input requirements are greater for supercritical water gasification. This study defines parameters for a model of the gasification reaction using the power law and Arrhenius equation. The activation energy was estimated to be 15 kJ/mol, and the reaction order was estimated to be 0.586. This model allows estimation of the size of a supercritical water reactor needed to replace the anaerobic digesters that are currently used at the wastewater treatment plant.

  13. Pretreatment of poultry manure anaerobic-digested effluents by electrolysis, centrifugation and autoclaving process for Chlorella vulgaris growth and pollutants removal.

    Science.gov (United States)

    Wang, Mengzi; Wu, Yu; Li, Baoming; Dong, Renjie; Lu, Haifeng; Zhou, Hongde; Cao, Wei

    2015-01-01

    Different pretreatments (electrolysis, centrifugation and autoclaving) coupled with Chlorella vulgaris biological system was used for the treatment of poultry manure anaerobic-digested effluents. The pretreated effluents were used as the growth medium for algal cultivation. The pollutant removal efficiencies of the combined treatments were determined. Electrochemical pretreatment can efficiently remove the ammonia (NH4+), total phosphorus (TP), total organic carbon (TOC), total carbon (TC), turbidity and bacteria in the digested effluents. About 100.0% NH4+, turbidity and bacteria, 97.6% TP, 81.5% TOC and 96.6% inorganic carbon were removed by 5-h electrochemical treatment. The maximal algal biomass accumulation (0.53 g L(-1)) was obtained from culture in the effluents pretreated with 2-h electrolysis. The pollutants removal amounts by the combination of electrolysis and biological treatment were much higher than the other combinations.

  14. 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.

  15. 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.

  16. Enhanced anaerobic digestion of food waste by thermal and ozonation pretreatment methods.

    Science.gov (United States)

    Ariunbaatar, Javkhlan; Panico, Antonio; Frunzo, Luigi; Esposito, Giovanni; Lens, Piet N L; Pirozzi, Francesco

    2014-12-15

    Treatment of food waste by anaerobic digestion can lead to an energy production coupled to a reduction of the volume and greenhouse gas emissions from this waste type. According to EU Regulation EC1774/2002, food waste should be pasteurized/sterilized before or after anaerobic digestion. With respect to this regulation and also considering the slow kinetics of the anaerobic digestion process, thermal and chemical pretreatments of food waste prior to mesophilic anaerobic digestion were studied. A series of batch experiments to determine the biomethane potential of untreated as well as pretreated food waste was carried out. All tested conditions of both thermal and ozonation pretreatments resulted in an enhanced biomethane production. The kinetics of the anaerobic digestion process were, however, accelerated by thermal pretreatment at lower temperatures (food waste, was obtained with thermal pretreatment at 80 °C for 1.5 h. On the basis of net energy calculations, the enhanced biomethane production could cover the energy requirement of the thermal pretreatment. In contrast, the enhanced biomethane production with ozonation pretreatment is insufficient to supply the required energy for the ozonator.

  17. Phylogenetic diversity and in situ detection of eukaryotes in anaerobic sludge digesters

    Science.gov (United States)

    Matsubayashi, Miri; Shimada, Yusuke; Li, Yu-You; Harada, Hideki

    2017-01-01

    Eukaryotic communities in aerobic wastewater treatment processes are well characterized, but little is known about them in anaerobic processes. In this study, abundance, diversity and morphology of eukaryotes in anaerobic sludge digesters were investigated by quantitative real-time PCR (qPCR), 18S rRNA gene clone library construction and catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). Samples were taken from four different anaerobic sludge digesters in Japan. Results of qPCR of rRNA genes revealed that Eukarya accounted from 0.1% to 1.4% of the total number of microbial rRNA gene copy numbers. The phylogenetic affiliations of a total of 251 clones were Fungi, Alveolata, Viridiplantae, Amoebozoa, Rhizaria, Stramenopiles and Metazoa. Eighty-five percent of the clones showed less than 97.0% sequence identity to described eukaryotes, indicating most of the eukaryotes in anaerobic sludge digesters are largely unknown. Clones belonging to the uncultured lineage LKM11 in Cryptomycota of Fungi were most abundant in anaerobic sludge, which accounted for 50% of the total clones. The most dominant OTU in each library belonged to either the LKM11 lineage or the uncultured lineage A31 in Alveolata. Principal coordinate analysis indicated that the eukaryotic and prokaryotic community structures were related. The detection of anaerobic eukaryotes, including the members of the LKM11 and A31 lineages in anaerobic sludge digesters, by CARD-FISH revealed their sizes in the range of 2–8 μm. The diverse and uncultured eukaryotes in the LKM11 and the A31 lineages are common and ecologically relevant members in anaerobic sludge digester. PMID:28264042

  18. Making lignin accessible for anaerobic digestion by wet-explosion pretreatment

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Biswas, Rajib; Ahamed, Aftab

    2015-01-01

    Lignin is a major part of the recalcitrant fraction of lignocellulose and in nature its degradation occurs through oxidative enzymes along with microbes mediated oxidative chemical actions. Oxygen assisted wet-explosion pretreatment promotes lignin solubility and leads to an increase biodegradation...... of lignin during anaerobic digestion processes. The pretreatment of feedlot manure was performed in a 10 L reactor at 170 C for 25 min using 4 bars oxygen and the material was fed to a continuous stirred tank reactor operated at 55 C for anaerobic digestion. Methane yield of untreated and pretreated...... material was 70 ± 27 and 320 ± 36 L/kg-VS/day, respectively, or 4.5 times higher yield as a result of the pretreatment. Aliphatic acids formed during the pretreatment were utilized by microbes. 44.4% lignin in pretreated material was actually converted in the anaerobic digestion process compared to 12...

  19. Microbial Anaerobic Digestion (Bio-Digesters) as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    OpenAIRE

    Manyi-Loh, Christy E.; Sampson N. Mamphweli; Meyer, Edson L.; Anthony I. Okoh; Makaka, Golden; Simon, Michael

    2013-01-01

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken d...

  20. Anaerobic digester for treatment of organic waste

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, V. K. [Indian Insitute of Technology, Delhi (India)]|[ENEA, Centro Ricerche Trisaia, Matera (Italy); Fortuna, F.; Canditelli, M.; Cornacchia, G. [ENEA, Centro Ricerche Trisaia, Matera (Italy). Dipt. Ambiente; Farina, R. [ENEA, centro Ricerche ``Ezio Clementel``, Bologna (Italy). Dipt. Ambiente

    1997-09-01

    The essential features of both new and more efficient reactor systems and their appropriate applications for various organic waste management situations, description of several working plants are discussed in the present communication. It is hoped that significant development reported here would be useful in opening a new vista to the application of anaerobic biotechnology for the waste treatment of both low/high organic strength and specialized treatment for toxic substances, using appropriate anaerobic methods.

  1. Biogas from renewable resources through dry anaerobic digestion; Biogas aus NaWaRos durch Trockenfermentation

    Energy Technology Data Exchange (ETDEWEB)

    Heiermann, M. [ATB, Potsdam (Germany). Abt. Technikbewertung und Stoffkreislaeufe; Linke, B. [ATB, Potsdam (Germany). Abt. Bioverfahrenstechnik; Kessler, U. [Agrargenossenschaft Pirow e.G. (Germany). Biogasanlage; Loock, R. [Ingenieurbuero Loock Consultants, Hamburg (Germany)

    2007-07-01

    The functionality, performance and operational safety of anaerobic digestion using the dry-wet simultaneous technique of Loock Consultants were investigated at the biogas pilot plant in Pirow (State Brandenburg). In addition to determining process parameters and the input and output balance of the digester, chemical characterisation of the substrates and their biogas production potential were determined in the laboratory. The results reveal that a substrate mixture of 60% maize silage, 13% poultry manure and 27% digested material on a mass basis deliver a methane yield of 90 m{sup 3}t{sup -1} fresh matter, if conducted as a three-week batch process. A specific methane yield performance of 0.34 m{sup 3}kg{sup -1} VS is attained, as with dry anaerobic digestion of maize silage, with the standard wet process. (orig.)

  2. Rheology evolution of sludge through high-solid anaerobic digestion.

    Science.gov (United States)

    Dai, Xiaohu; Gai, Xin; Dong, Bin

    2014-12-01

    The main purpose of this study was to investigate the rheology evolution of sludge through high-solid anaerobic digestion (AD) and its dependency on sludge retention time (SRT) and temperature of AD reactor. The operation performance of high-solid AD reactors were also studied. The results showed that sludge became much more flowable after high-solid AD. It was found that the sludge from reactors with long SRT exhibited low levels of shear stress, viscosity, yield stress, consistency index, and high value of flow behaviour index. While the flowability of sludge from thermophilic AD reactors were better than that of sludge from mesophilic AD reactors though the solid content of the formers were higher than that of the latters, which could be attributed to the fact that the formers had more amount of free and interstitial moisture. It might be feasible to use sludge rheology as an AD process controlling parameter.

  3. Timeline of bio-hydrogen production by anaerobic digestion of biomass

    OpenAIRE

    Bernadette E. TELEKY; Mugur C. BĂLAN; Nikolausz, Marcell

    2015-01-01

    Anaerobic digestion of biomass is a process capable to produce biohydrogen, a clean source of alternative energy. Lignocellulosic biomass from agricultural waste is considered a renewable energy source; therefore its utilization also contributes to the reduction of water, soil and air pollution. The study consists in five consecutive experiments designed to utilize anaerobic bacterial enrichment cultures originating from the Hungarian Lake, Hévíz. Wheat straw was used as com...

  4. Pilot-scale gasification of municipal solid wastes by high-rate and two-phase anaerobic digestion (TPAD).

    Science.gov (United States)

    Ghosh, S; Henry, M P; Sajjad, A; Mensinger, M C; Arora, J L

    2000-01-01

    Bioconversion of municipal solid waste-sludge blend by conventional high-rate and two-phase anaerobic digestion was studied. RDF (refused-derived fuel)-quality feed produced in a Madison, Wisconsin, USA, MRF (materials-recovery facility) was used. High-rate digestion experiments were conducted with bench-scale digesters under target operating conditions developed from an economic feasibility study. The effects of digestion temperature, RDF content of digester feed, HRT, loading rate, RDF particle size, and RDF pretreatment with cellulase or dilute solutions of NaOH or lime on digester performance were studied. A pilot-scale two-phase digestion plant was operated with 80:20 (weight ratio) RDF-sludge blends to show that this process exhibited a higher methane yield, and produced a higher methane-content digester gas than those obtained by single-stage, high-rate anaerobic digestion.

  5. Methane production during storage of anaerobically digested municipal organic waste.

    Science.gov (United States)

    Hansen, Trine Lund; Sommer, Svend G; Gabriel, Søren; Christensen, Thomas H

    2006-01-01

    Anaerobic digestion of source-separated municipal organic waste is considered feasible in Denmark. The limited hydraulic retention in the biogas reactor (typically 15 d) does not allow full degradation of the organic waste. Storage of anaerobically digested municipal organic waste can therefore be a source of methane (CH4) emission that may contribute significantly to the potential global warming impact from the waste treatment system. This study provides a model for quantifying the CH4 production from stored co-digested municipal organic waste and estimates the production under typical Danish climatic conditions, thus quantifying the potential global warming impact from storage of the digested municipal organic waste before its use on agricultural land. Laboratory batch tests on CH4 production as well as temperature measurements in eight full-scale storage tanks provided data for developing a model estimating the CH4 production in storage tanks containing digested municipal organic waste. The temperatures measured in separate storage tanks on farms receiving digested slurry were linearly correlated with air temperature. In storage tanks receiving slurry directly from biogas reactors, significantly higher temperatures were measured due to the high temperatures of the effluent from the reactor. Storage tanks on Danish farms are typically emptied in April and have a constant inflow of digested material. During the warmest months the content of digested material is therefore low, which limits the yearly CH4 production from storage.

  6. Anaerobic digestion of thin stillage for energy recovery and water reuse in corn-ethanol plants.

    Science.gov (United States)

    Alkan-Ozkaynak, A; Karthikeyan, K G

    2011-11-01

    Recycling of anaerobically-digested thin stillage within a corn-ethanol plant may result in the accumulation of nutrients of environmental concern in animal feed coproducts and inhibitory organic materials in the fermentation tank. Our focus is on anaerobic digestion of treated (centrifugation and lime addition) thin stillage. Suitability of digestate from anaerobic treatment for reuse as process water was also investigated. Experiments conducted at various inoculum-to-substrate ratios (ISRs) revealed that alkalinity is a critical parameter limiting digestibility of thin stillage. An ISR level of 2 appeared optimal based on high biogas production level (763 mL biogas/g volatile solids added) and organic matter removal (80.6% COD removal). The digester supernatant at this ISR level was found to contain both organic and inorganic constituents at levels that would cause no inhibition to ethanol fermentation. Anaerobic digestion of treated-thin stillage can be expected to improve the water and energy efficiencies of dry grind corn-ethanol plants.

  7. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter.

    Science.gov (United States)

    Gannoun, H; Bouallagui, H; Okbi, A; Sayadi, S; Hamdi, M

    2009-10-15

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/Ld. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  8. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

    Energy Technology Data Exchange (ETDEWEB)

    Gannoun, H.; Bouallagui, H.; Okbi, A. [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia); Sayadi, S. [Laboratory of bioprocesses, Centre of Biotechnology of Sfax, Sfax (Tunisia); Hamdi, M., E-mail: moktar.hamdi@insat.rnu.tn [Laboratory of Microbial Ecology and Technology, Department of Biological and Chemical Engineering, National Institute of Applied Sciences and Technology, B.P. 676, 1080 Tunis (Tunisia)

    2009-10-15

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 deg. C) and thermophilic (55 deg. C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6 g COD/L d in mesophilic conditions and at OLRs from 0.9 to 9 g COD/L d in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/L d in mesophilic conditions, while the highest OLRs i.e. 9 g COD/L d led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/L d. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  9. Relationship between microbial activity and microbial community structure in six full-scale anaerobic digesters

    NARCIS (Netherlands)

    Regueiro, L.; Veiga, P.; Figueroa, M.; Alonso-Gutierrez, J.; Stams, A.J.M.; Lema, J.M.; Carballa, M.

    2012-01-01

    High activity levels and balanced anaerobic microbial communities are necessary to attain proper anaerobic digestion performance. Therefore, this work was focused on the kinetic performance and the microbial community structure of six full-scale anaerobic digesters and one lab-scale co-digester. Hyd

  10. Wet and Dry Anaerobic Digestion of Biowaste and of Co-substrates

    OpenAIRE

    Li, Chaoran

    2015-01-01

    Treatment of municipal solid waste by anaerobic digestion can solve the environmental problems caused by this organic solid waste and also supply biogas as renewable energy for a sustainable development. In this study the improvement of wet anaerobic digestion by addition of co-substrates and the effect of moisture on dry anaerobic digestion were investigated.

  11. Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2006-01-01

    Different process strategies for anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) are reviewed weighing high-solids versus low-solids, mesophilic versus thermophilic and single-stage versus multi-stage processes. The influence of different waste characteristics...

  12. Determination of greenhouse gas emission reductions from sewage sludge anaerobic digestion in China.

    Science.gov (United States)

    Liu, H-T; Kong, X-J; Zheng, G-D; Chen, C-C

    2016-01-01

    Sewage sludge is a considerable source of greenhouse gas (GHG) emission in the field of organic solid waste treatment and disposal. In this case study, total GHG emissions from sludge anaerobic digestion, including direct and indirect emissions as well as replaceable emission reduction due to biogas being reused instead of natural gas, were quantified respectively. The results indicated that no GHG generation needed to be considered during the anaerobic digestion process. Indirect emissions were mainly from electricity and fossil fuel consumption on-site and sludge transportation. Overall, the total GHG emission owing to relative subtraction from anaerobic digestion rather than landfill, and replaceable GHG reduction caused by reuse of its product of biogas, were quantified to be 0.7214 (northern China) or 0.7384 (southern China) MgCO2 MgWS(-1) (wet sludge).

  13. Optimization of the operation of the anaerobic digestion in a water treatment plant; Optimizacion de la explotacion de la digestion anaerobia en una EDAR

    Energy Technology Data Exchange (ETDEWEB)

    Minguez Gabina, R.

    2002-07-01

    Nowadays the companies demand an optimization of the operation in an anaerobic digestion facility in a water treatment plant. Up to now, the practice of this operation has been made controlling the internal parameters of the digester experimentally. The delay in the application of the corrections is enough to decrease the performances. Thanks to the investigation carried out in the water treatment plants of Lleida an Granollers, we conclude that the most secure way to drive the anaerobic digester is to manage a strict control of the inlet parameters into digestion process. (Author)

  14. Use of gamma-irradiation pretreatment for enhancement of anaerobic digestibility of sewage sludge

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of y-irradiation pretreatment on anaerobic digestibility of sewage sludge was investigated in this paper.Parameters like solid components,soluble components,and biogas production of anaerobic digestion experiment for sewage sludge were measured.The values of these parameters were compared before and after y-irradiation pretreatment.Total solid (TS),volatile solid (VS),suspended solid (SS),volatile suspended solid (VSS),and average floc size of samples decreased after γ-irradiation treatment.Besides,floc size distribution of sewage sludge shifted from 80-100 μm to 0-40 μm after y-irradiation treatment at the doses from 0 to 30 kGy,which indicated the disintegration of sewage sludge.Moreover,microbe cells of sewage sludge were ruptured by γ-irradiation treatment,which resulted in the release of cytoplasm and increase of soluble chemical oxygen demand (SCOD).Both sludge disintegration and microbe cells rupture enhanced the subsequent anaerobic digestion process,which was demonstrated by the increase of accumulated biogas production.Compared with digesters fed with none irradiated sludge,the accumulated biogas production increased 44,98,and 178 mL for digesters fed sludge irradiated at 2.48,6.51,and 11.24 kGy,respectively.The results indicated that "/-irradiation pretreatment could effectively enhance anaerobic digestibility of sewage sludge,and correspondingly,could accelerate hydrolysis process,shorten sludge retention time of sludge anaerobic digestion process.

  15. Stability and Uniform Boundedness for a Class of Anaerobic Digestion Ecological Models

    Institute of Scientific and Technical Information of China (English)

    LI Ming-qi

    2004-01-01

    Stability, boundedness and persistence are three important aspects for an ecological model. In this paper, a further analysis ora class of anaerobic digestion ecological models is performed.Based on the Liupunov Method, the local stability of all equilibria in the system is got. According to the vector fields described by the system, the proof of the boundedness of the solution on the anaerobic digestion processes is completed in three steps. The method proposed in the discussion on the boundedness can be generalized to the similar problems. Results in this paper give information on how to run the ecological system well by adjusting the system parameters.

  16. ANIMAL MANURE – REDUCED QUALITY BY ANAEROBIC DIGESTION?

    DEFF Research Database (Denmark)

    Løes, Anne-Kristin; Johansen, Anders; Pommeresche, Reidun;

    2014-01-01

    Anaerobic digestion may reduce emissions of greenhouse gases, but we know little about its impact on soil fertility. Reduced concentrations of easily degradable C in the manure may imply less food for the soil fauna and microflora. A field experiment to study its effect on crop yields and soil...

  17. Toxicity of nonylphenol diethoxylate in lab-scale anaerobic digesters

    DEFF Research Database (Denmark)

    Bozkurt, Hande; Sanin, F. Dilek

    2014-01-01

    diethoxylate (NP2EO), for anaerobic digestion of sludge was determined. The test bottles were dosed with NP2EO in acetone, with concentrations ranging from 1mgL-1 to 30mgL-1. During the tests, gas productions and compositions in terms of methane and carbon dioxide were monitored. To be able to judge about...

  18. Phosphorus uptake by potato from fertilizers recovered from anaerobic digestion

    Science.gov (United States)

    Field experiments were conducted in the Columbia Basin of South Central Washington to assess the yield of potato (Solanum tuberosum) in response to application of phosphorus enriched materials recovered from anaerobic digestion of manure. The treatments were comprised of four rates (0, 56, 112 and ...

  19. INCREASE OF INDICATOR ORGANISMS FOLLOWING ANAEROBIC DIGESTION AND CENTRIFUGE DEWATERING.

    Science.gov (United States)

    The Water Environment Research Foundation (WERF) recently published a report titled “Examination of Reactivation and Regrowth of Fecal Coliforms in Anaerobically Digested Sludges”. Seven full-scale publicly owned treatment facilities were sampled several times to determine if bac...

  20. Biogas energy production from tropical biomass wastes by anaerobic digestion

    Science.gov (United States)

    Anaerobic digestion (AD) is an attractive technology in tropical regions for converting locally abundant biomass wastes into biogas which can be used to produce heat, electricity, and transportation fuels. However, investigations on AD of tropical forestry wastes, such as albizia biomass, and food w...

  1. Anaerobic Digestion Analysis. Training Module 5.120.2.77.

    Science.gov (United States)

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with alkalinity, volatile acids and carbon dioxide determinations for an anaerobic sludge digester. Included are objectives, instructor guides, student handouts and transparency masters. This module considers total and bicarbonate…

  2. Anaerobic digestion of cassava starch factory effluent.

    Science.gov (United States)

    Manilal, V B; Narayanan, C S; Balagopalan, C

    1990-06-01

    Biomethanation of cassava starch factory effluent in a batch digester produced 130 l biogas/kg dry matter with an average melthane content of 59%. About 63% COD was removed during 60 days. In semicontinuous digesters, gas production was 3251/kg dry matter with a retention time of 33,3 days giving a COD reduction of 50%. Size of starter inoculum was important for good biogasification of the effluent.

  3. Innovative bioelectrochemical-anaerobic-digestion integrated system for ammonia recovery and bioenergy production from ammonia-rich residues

    OpenAIRE

    Zhang, Yifeng; Angelidaki, Irini

    2015-01-01

    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 (Figure 1). In batch experiment, th...

  4. 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.)

  5. 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.

  6. Environmental assessment of farm-scaled anaerobic co-digestion for bioenergy production

    Energy Technology Data Exchange (ETDEWEB)

    Lijó, Lucía, E-mail: lucia.lijo@usc.es [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); González-García, Sara [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain); Bacenetti, Jacopo; Negri, Marco; Fiala, Marco [Department of Agricultural and Environmental Sciences, Production, Landscape, Agroenergy, University of Milan, Milan (Italy); Feijoo, Gumersindo; Moreira, María Teresa [Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, 15782 Santiago de Compostela (Spain)

    2015-07-15

    Highlights: • Anaerobic monodigestion and codigestion were compared. • The environmental advantages of suitable waste management were proved. • The use of cereal crops as feedstock improves biogas yield. • Cultivation step implies the most important environmental hotspot. • Digestate management options were evaluated. - Abstract: The aim of this study was to assess the environmental profile of a bioenergy system based on a co-digestion plant using maize silage and pig slurry as substrates. All the processes involved in the production of bioenergy as well as the avoided processes accrued from the biogas production system were evaluated. The results evidenced the environmental importance of the cultivation step and the environmental credits associated to the avoided processes. In addition, this plant was compared with two different plants that digest both substrates separately. The results revealed the environmental benefits of the utilisation of pig slurry due to the absence of environmental burdens associated with its production as well as credits provided when avoiding its conventional management. The results also presented the environmental drawbacks of the utilisation of maize silage due to the environmental burdens related with its production. Accordingly, the anaerobic mono-digestion of maize silage achieved the worst results. The co-digestion of both substrates was ranked in an intermediate position. Additionally, three possible digestate management options were assessed. The results showed the beneficial effect of digestate application as an organic fertiliser, principally on account of environmental credits due to avoided mineral fertilisation. However, digestate application involves important acidifying and eutrophicating emissions.

  7. Modeling temperature variations in a pilot plant thermophilic anaerobic digester.

    Science.gov (United States)

    Valle-Guadarrama, Salvador; Espinosa-Solares, Teodoro; López-Cruz, Irineo L; Domaschko, Max

    2011-05-01

    A model that predicts temperature changes in a pilot plant thermophilic anaerobic digester was developed based on fundamental thermodynamic laws. The methodology utilized two simulation strategies. In the first, model equations were solved through a searching routine based on a minimal square optimization criterion, from which the overall heat transfer coefficient values, for both biodigester and heat exchanger, were determined. In the second, the simulation was performed with variable values of these overall coefficients. The prediction with both strategies allowed reproducing experimental data within 5% of the temperature span permitted in the equipment by the system control, which validated the model. The temperature variation was affected by the heterogeneity of the feeding and extraction processes, by the heterogeneity of the digestate recirculation through the heating system and by the lack of a perfect mixing inside the biodigester tank. The use of variable overall heat transfer coefficients improved the temperature change prediction and reduced the effect of a non-ideal performance of the pilot plant modeled.

  8. 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.

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

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    (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 concentration in the CSTR decreased from 6 to 0.7 g-N/L with an average recovery rate of 0.18 g......-N/L(CSTR)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m2 was produced (10 Ω). Both current driven NH4+ migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMRC...

  10. Influence of the food to microorganisms (F/M) ratio and temperature on batch anaerobic digestion processes with and without zeolite addition.

    Science.gov (United States)

    Montalvo, S; Gonzalez, P; Mena, C; Guerrero, L; Borja, R

    2012-01-01

    The main objective of this work was to evaluate the influence of the food to microorganisms (F/M) ratio and temperature on batch anaerobic digestion processes carried out with and without zeolite addition as a microbial carrier. Three laboratory-scale experimental runs were conducted using a synthetic substrate with a COD:N:P ratio of 500:5:1. The first run (I) was conducted at a constant temperature of 27°C, increasing the F/M ratio from 0.21 to 0.40 (g COD/g VSS). During the second run (II) the temperature and the F/M ratio increased from 27°C to 37°C and from 0.21 to 0.40, respectively. Finally, in the third experimental run (III) the F/M ratio achieved high values (1.92 and 1.30) either by varying the substrate concentration at a constant biomass concentration or by increasing the biomass concentration at a constant substrate concentration. Higher biomass growth rate, COD removal and methane production were found in the reactors with zeolite, especially at the highest F/M assayed during the first run. The highest ammonium removals were also achieved at the highest F/M ratio (0.40) in the reactors with zeolite. Within the range studied (25°C-37°C) in the reactors with zeolite operating at 37°C, the second run demonstrated the low influence of temperature on substrate consumption and ammonia removal, with 93% and 70% of COD and ammonia removal efficiencies, respectively. The third run corroborated the results previously obtained and fit the experimental results to simple kinetic models, the Monod model being the most adequate for predicting the behavior of the systems studied. The maximum specific microorganism growth rate (μ(max)) values for the reactors with zeolite were almost twice as high as those obtained for the reactors without zeolite for similar F/M ratios.

  11. Anaerobic digestion as final step of a cellulosic ethanol biorefinery:

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Ahring, Birgitte Kiær

    2010-01-01

    In order to lower the costs for second generation bioethanol from lignocellulosic biomass anaerobic digestion of the effluent from ethanol fermentation was implemented using an upflow anaerobic sludge blanket (UASB) reactor system in a pilot-scale biorefinery plant. Both thermophilic (538C...... were, however, higher under mesophilic conditions compared to thermophilic conditions. The conversion of dissolved organic matter (VSdiss) was between 68% and 91%. The effluent from the ethanol fermentation showed no signs of toxicity to the anaerobic microorganisms. However, a high content...... of suspended matter reduced the degradation efficiency. The retention time of the anaerobic system could be reduced from 70 to 7 h by additional removal of suspended matter by clarification. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher carbon utilization...

  12. Psychrophilic anaerobic digestion of swine manure slurry in sequencing batch reactors

    Energy Technology Data Exchange (ETDEWEB)

    Masse, D.I. [Agriculture Canada, Ottawa, ON (Canada). Food Research Branch; Droste, R.L. [Ottawa Univ., ON (Canada). Dept. of Civil Engineering

    1993-12-31

    This work presents preliminary results of an ongoing laboratory study to evaluate the feasibility of psychrophilic anaerobic digestion in sequencing batch reactors (SBR) for stabilizing, deodorizing and adding value to swine manure. Preliminary results show that the process is feasible. (author). 14 refs., 7 tabs.

  13. Anaerobic digestion foaming in full-scale biogas plants: A survey on causes and solutions

    DEFF Research Database (Denmark)

    Kougias, Panagiotis; Boe, Kanokwan; O-Thong, Sompong;

    2014-01-01

    Anaerobic digestion foaming is a common operation problem in biogas plants with negative impacts on the biogas plants economy and environment. A survey of 16 Danish full-scale biogas plants on foaming problems revealed that most of them had experienced foaming in their processes up to three times...

  14. Anaerobic Digestion. Selected Instructional Activities and References. Instructional Resources Monograph Series.

    Science.gov (United States)

    Townsend, Robert D., Comp.

    Focusing specifically on the wastewater treatment process of anaerobic digestion, this document identifies instructional and reference materials for use by professionals in the field in the development and implementation of new programs or in the updating of existing programs. It is designed to help trainers, plant operators, educators, engineers,…

  15. Anaerobic Digestion of Saline Creeping Wild Ryegrass for Biogas Production and Pretreatment of Particleboard Material

    Science.gov (United States)

    The objective of this research was to develop an integrated process to produce biogas and high-quality particleboard using saline creeping wild ryegrass (CWR), Leymus triticoides through anaerobic digestion (AD). Besides producing biogas, AD also serves as a pretreatment method to remove the wax la...

  16. Preparation of volatile fatty acid (VFA) calcium salts by anaerobic digestion of glucose.

    Science.gov (United States)

    Li, Xiaofen; Swan, Janis E; Nair, Giridhar R; Langdon, Alan G

    2015-01-01

    Many potentially useful intermediates such as hydrogen and volatile fatty acids (VFAs) are formed during the complex anaerobic digestion processes that produce methane from biomass. This study recovers VFAs from an anaerobic digester by a combination of gas stripping and absorption with calcium carbonate slurry. Glucose was used as the model substrate because it is readily available, inexpensive, and easily digested. Sludge from a meatworks anaerobic digester produced methane and carbon dioxide (and sometimes a small amount of hydrogen) when batch-fed with glucose. Conditioning the neutral anaerobic sludge to an acidic pH (below 4.8) was achieved using repeated 1 g L(-1) doses of glucose. After conditioning, mainly VFAs and hydrogen were produced. The intermediate VFAs could be stripped using headspace gas. In subsequent fed-batch digestion/stripping cycles, the pH decreased when glucose was added and then increased when the VFA was gas stripped. The predominant acids formed at low pH values were lactic, butyric, and acetic acids. Lactic acid was converted to VFAs during stripping. The VFA calcium salts recovered were 80% butyrate and 20% acetate with minor quantities of propionate and valerate.

  17. Inoculum selection is crucial to ensure operational stability in anaerobic digestion.

    Science.gov (United States)

    De Vrieze, Jo; Gildemyn, Sylvia; Vilchez-Vargas, Ramiro; Jáuregui, Ruy; Pieper, Dietmar H; Verstraete, Willy; Boon, Nico

    2015-01-01

    Anaerobic digestion is considered a key technology for the future bio-based economy. The microbial consortium carrying out the anaerobic digestion process is quite complex, and its exact role in terms of "elasticity", i.e., the ability to rapidly adapt to changing conditions, is still unknown. In this study, the role of the initial microbial community in terms of operational stability and stress tolerance was evaluated during a 175-day experiment. Five different inocula from stable industrial anaerobic digesters were fed a mixture of waste activated sludge and glycerol. Increasing ammonium pulses were applied to evaluate stability and stress tolerance. A different response in terms of start-up and ammonium tolerance was observed among the different inocula. Methanosaetaceae were the dominant acetoclastic methanogens, yet, Methanosarcinaceae increased in abundance at elevated ammonium concentrations. A shift from a Firmicutes to a Proteobacteria dominated bacterial community was observed in failing digesters. Methane production was strongly positively correlated with Methanosaetaceae, but also with Bacteria related to Anaerolinaceae, Clostridiales, and Alphaproteobacteria. Volatile fatty acids were strongly positively correlated with Betaproteobacteria and Bacteroidetes, yet ammonium concentration only with Bacteroidetes. Overall, these results indicate the importance of inoculum selection to ensure stable operation and stress tolerance in anaerobic digestion.

  18. Anaerobic digestion of wastewater screenings for resource recovery and waste reduction

    Science.gov (United States)

    Wid, N.; Horan, N. J.

    2016-06-01

    Wastewater screenings are produced during the first stage of the wastewater treatment process and at present are disposed of to landfill. This material may not only cause operational failure to the treatment system, but also lead to environmental problems. In view of the high organic content of screenings, anaerobic digestion method may not only offer the potential for energy recovery, but also nutrient. In this study the, anaerobic batch digestion was performed at different dry solids concentrations of screenings to study the potential of biogas and phosphorus recovery. The tests demonstrated wastewater screenings were amenable to anaerobic digestion with methane yield was 355 m3/kg VS, which are comparable to the previous results. The digestate was high in P content and can be recovered up to 41%. This study also shows that anaerobic digestion was not only to turn this waste into useful resources, but also has a potential in reducing the organic content up to 31% for safe disposal. In this way the amount of wastewater screenings going to landfill is not only can be reduced, but also valuable products such as methane and phosphorus can also be recovered.

  19. Monitoring methanogenic population dynamics in a full-scale anaerobic digester to facilitate operational management.

    Science.gov (United States)

    Williams, Julie; Williams, Haydn; Dinsdale, Richard; Guwy, Alan; Esteves, Sandra

    2013-07-01

    Microbial populations in a full-scale anaerobic digester fed on food waste were monitored over an 18-month period using qPCR. The digester exhibited a highly dynamic environment in which methanogenic populations changed constantly in response to availability of substrates and inhibitors. The methanogenic population in the digester was dominated by Methanosaetaceae, suggesting that aceticlastic methanogenesis was the main route for the production of methane. Sudden losses (69%) in Methanosaetaceae were followed by a build-up of VFAs which were subsequently consumed when populations recovered. A build up of ammonium inhibited Methanosaetaceae and resulted in shifts from acetate to hydrogen utilization. Addition of trace elements and alkalinity when propionate levels were high stimulated microbial growth. Routine monitoring of microbial populations and VFAs provided valuable insights into the complex processes occurring within the digester and could be used to predict digester stability and facilitate digester optimization.

  20. Extracellular polymeric substances and dewaterability of waste activated sludge during anaerobic digestion.

    Science.gov (United States)

    Ye, Fenxia; Liu, Xinwen; Li, Ying

    2014-01-01

    Anaerobic digestion of waste activated sludge was conducted to gain insight into the mechanisms underlying change in sludge dewaterability during its anaerobic digestion. Unexpectedly, the results indicated that sludge dewatering properties measured by capillary suction time only deteriorated after 10 days of anaerobic digestion, after which dewaterability recovered and remained stable. The loosely bound extracellular polymeric substance (LB-EPS) content increased three-fold after 20 days of anaerobic digestion, and did not change significantly during the remaining 30 days. The tightly bound EPS (TB-EPS) content reduced slightly after 20 days of anaerobic digestion, and stabilized during the last 30 days. Polysaccharides (PS) and proteins (PN) content in LB-EPS increased after 10 days of anaerobic digestion. However, PS and PN contents in TB-EPS decreased slightly. The relationship analysis showed that only LB-EPS correlated with dewaterability of the sludge during anaerobic digestion.

  1. Bioaugmentation with an acetate-oxidising consortium as a tool to tackle ammonia inhibition of anaerobic digestion

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2013-01-01

    Ammonia is the major inhibitor of anaerobic digestion (AD) process in biogas plants. In the current study, the bioaugmentation of the ammonia tolerant SAO co-culture (i.e. Clostridium ultunense spp. nov. in association with Methanoculleus spp. strain MAB1) in a mesophilic up-flow anaerobic sludge...

  2. [Isolation, Identification and Characteristic Analysis of an Oil-producing Chlorella sp. Tolerant to High-strength Anaerobic Digestion Effluent].

    Science.gov (United States)

    Yang, Chuang; Wang, Wen-guo; Ma, Dan-wei; Tang, Xiao-yu; Hu, Qi-chun

    2015-07-01

    A Chlorella strain tolerant to high-strength anaerobic digestion effluent was isolated from the anaerobic digestion effluent with a long-term exposure to air. The strain was identified as a Chlorella by morphological and molecular biological methods, and named Chlorella sp. BWY-1, The anaerobic digestion effluent used in this study was from a biogas plant with the raw materials of swine wastewater after solid-liquid separation. The Chlorella regularis (FACHB-729) was used as the control strain. The comparative study showed that Chlorella sp, BWY-Ihad relatively higher growth rate, biomass accumulation capacity and pollutants removal rate in BG11. and different concentrations of anaerobic digestion effluent. Chlorella sp. BWY-1 had the highest growth rate and biomass productivity (324.40 mg.L-1) in BG11, but its lipid productivity and lipid content increased with the increase of anaerobic digestion effluent concentration, In undiluted anaerobic digestion effluent, the lipid productivity and lipid content of Chlorella sp. BWY-1 were up to 44. 43% and 108. 70 mg.L-1, respectively. Those results showed that the isolated algal strain bad some potential applications in livestock wastewater treatment and bioenergy production, it could be combined with a solid-liquid separation, anaerobic fermentation and other techniques for processing livestock wastewater and producing biodiesel.

  3. Counteracting ammonia inhibition in anaerobic digestion by removal with a hollow fiber membrane contactor.

    Science.gov (United States)

    Lauterböck, B; Ortner, M; Haider, R; Fuchs, W

    2012-10-01

    The aim of the current study was to investigate the feasibility of membrane contactors for continuous ammonia (NH₃-N) removal in an anaerobic digestion process and to counteract ammonia inhibition. Two laboratory anaerobic digesters were fed slaughterhouse wastes with ammonium (NH₄⁺) concentrations ranging from 6 to 7.4 g/L. One reactor was used as reference reactor without any ammonia removal. In the second reactor, a hollow fiber membrane contactor module was used for continuous ammonia removal. The hollow fiber membranes were directly submerged into the digestate of the anaerobic reactor. Sulfuric acid was circulated in the lumen as an adsorbent solution. Using this set up, the NH₄⁺-N concentration in the membrane reactor was significantly reduced. Moreover the extraction of ammonia lowered the pH by 0.2 units. In combination that led to a lowering of the free NH₃-N concentration by about 70%. Ammonia inhibition in the reference reactor was observed when the concentration exceeded 6 g/L NH₄⁺-N or 1-1.2 g/L NH₃-N. In contrast, in the membrane reactor the volatile fatty acid concentration, an indicator for process stability, was much lower and a higher gas yield and better degradation was observed. The chosen approach offers an appealing technology to remove ammonia directly from media having high concentrations of solids and it can help to improve process efficiency in anaerobic digestion of ammonia rich substrates.

  4. Anaerobic digestion in mesophilic and room temperature conditions: Digestion performance and soil-borne pathogen survival.

    Science.gov (United States)

    Chen, Le; Jian, Shanshan; Bi, Jinhua; Li, Yunlong; Chang, Zhizhou; He, Jian; Ye, Xiaomei

    2016-05-01

    Tomato plant waste (TPW) was used as the feedstock of a batch anaerobic reactor to evaluate the effect of anaerobic digestion on Ralstonia solanacearum and Phytophthora capsici survival. Batch experiments were carried out for TS (total solid) concentrations of 2%, 4% and 6% respectively, at mesophilic (37±1°C) and room (20-25°C) temperatures. Results showed that higher digestion performance was achieved under mesophilic digestion temperature and lower TS concentration conditions. The biogas production ranged from 71 to 416L/kg VS (volatile solids). The inactivation of anaerobic digestion tended to increase as digestion performance improved. The maximum log copies reduction of R. solanacearum and P. capsici detected by quantitative PCR (polymerase chain reaction) were 3.80 and 4.08 respectively in reactors with 4% TS concentration at mesophilic temperatures. However, both in mesophilic and room temperature conditions, the lowest reduction of R. solanacearum was found in the reactors with 6% TS concentration, which possessed the highest VFA (volatile fatty acid) concentration. These findings indicated that simple accumulation of VFAs failed to restrain R. solanacearum effectively, although the VFAs were considered poisonous. P. capsici was nearly completely dead under all conditions. Based on the digestion performance and the pathogen survival rate, a model was established to evaluate the digestate biosafety.

  5. Trace elements induce predominance among methanogenic activity in anaerobic digestion

    Directory of Open Access Journals (Sweden)

    Babett Wintsche

    2016-12-01

    Full Text Available Trace elements play an essential role in all organisms due to their functions in enzyme complexes. In anaerobic digesters, control and supplementation of trace elements lead to stable and more efficient methane production processes while trace element deficits cause process imbalances. However, the underlying metabolic mechanisms and the adaptation of the affected microbial communities to such deficits are not yet fully understood. Here, we investigated the microbial community dynamics and resulting process changes induced by trace element deprivation. Two identical lab-scale continuous stirred tank reactors fed with distiller’s grains and supplemented with trace elements (cobalt, molybdenum, nickel, tungsten and a commercial iron additive were operated in parallel. After 72 weeks of identical operation, the feeding regime of one reactor was changed by omitting trace element supplements and reducing the amount of iron additive. Both reactors were operated for further 21 weeks. Various process parameters (biogas production and composition, total solids and volatile solids, trace element concentration, volatile fatty acids, total ammonium nitrogen, total organic acids/alkalinity ratio, and pH and the composition and activity of the microbial communities were monitored over the total experimental time. While the methane yield remained stable, the concentrations of hydrogen sulfide, total ammonia nitrogen, and acetate increased in the trace element-depleted reactor compared to the well-supplied control reactor. Methanosarcina and Methanoculleus dominated the methanogenic communities in both reactors. However, the activity ratio of these two genera was shown to depend on trace element supplementation explainable by different trace element requirements of their energy conservation systems. Methanosarcina dominated the well-supplied anaerobic digester, pointing to acetoclastic methanogenesis as the dominant methanogenic pathway. Under trace element

  6. A spreadsheet calculator for estimating biogas production and economic measures for UK-based farm-fed anaerobic digesters.

    Science.gov (United States)

    Wu, Anthony; Lovett, David; McEwan, Matthew; Cecelja, Franjo; Chen, Tao

    2016-11-01

    This paper presents a spreadsheet calculator to estimate biogas production and the operational revenue and costs for UK-based farm-fed anaerobic digesters. There exist sophisticated biogas production models in published literature, but the application of these in farm-fed anaerobic digesters is often impractical. This is due to the limited measuring devices, financial constraints, and the operators being non-experts in anaerobic digestion. The proposed biogas production model is designed to use the measured process variables typically available at farm-fed digesters, accounting for the effects of retention time, temperature and imperfect mixing. The estimation of the operational revenue and costs allow the owners to assess the most profitable approach to run the process. This would support the sustained use of the technology. The calculator is first compared with literature reported data, and then applied to the digester unit on a UK Farm to demonstrate its use in a practical setting.

  7. Anaerobic digestion of solid biomass and biowaste

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    Within the International Trade Fair for Biogas Plant Technology from 23rd to 24th February, 2012 in Berlin, the following lectures were held: (1) Presentation and results of the EU project 24biomass'' (Claudia Lutsyuk); (2) The Polish biogas market (Tomasz Surowiec); (3) Presence and future of the biogas sector in Poland - EBE project (Eugeniusz Jedrysik); (4) Modern biogas generation in Poland - Case studies of the company Poldanor (Jens Bo Holm-Nielsen); (5) Low space requirement - The challenge in the integration of biogas plants in existing composting facilities - examples from real life (Michael Oertig); (6) Integration of biogas plants in composting facilities by partial-flow fermentation (Bruno Mattheeuws); (7) The significance of an efficient removal of foreign matter from biomass before fermentation in a waste incinerator for municipal wastes (Stephan Schulte); (8) Sustainable enhancement of the anaerobic degradation and increase of the biogas production by means of ultrasonic treatment - examples from real life (Silvana Velten); (9) Cultivation of energy plants on sandy soils in the northeastern part of Germany (Gunter Ebel); (10) Topinambur, a new sustainable energy crop for biogas generation (Vito Pignatelli); (11) Potential of biogas generation from reed (Vilis Dubrovskis); (12) Biogas generation from maize straw - a new procedure of harvesting and processing (Thomas Amon); (13) Generation of biogas by cofermentation of pig manure and grass silage: a pilot study (Ximmin Zhan); (14) Thermophilic dry fermentation of poultry litter and energy crops for the generation of biogas, organic fertilizer and protection of water resources from environmental damages in the Mid-Atlantic region of the USA (John Intersoll); (15) Energetic utilisation of horse manure (Saskia Oldenburg); (16) Realization of the greatest and most modern Hungarian biogas plant in Szarvas (Ludwig Dinkloh); (16) Biogas in Russia - The investment program of the cooperation &apos

  8. High-solid Anaerobic Co-digestion of Food Waste and Rice Straw for Biogas Production

    Institute of Scientific and Technical Information of China (English)

    Pei Zhan-jiang; Liu Jie; Shi Feng-mei; Wang Su; GaoYa-bing; Zhang Da-lei

    2014-01-01

    Anaerobic co-digestion of food waste (FW) and rice straw (RS) in continuously stirred tank reactor (CSTR) at high organic loading rate (OLR) was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid (VS) concentration of more than 3 gVS•L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand (COD) and volatile fatty acids (VFAs) were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 mL•gV•S-1•d-1 at a mass ratio (FW/RS) of 3: 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than mono-digestions in higher organic loading system.

  9. Anaerobic digestion of pig manure and glycerol from biodiesel production

    Directory of Open Access Journals (Sweden)

    Pakamas Chetpattananondh, Sumate Chaiprapat, Chaisri Suksaroj

    2015-01-01

    Full Text Available Increasing biodiesel production causes a surplus of glycerol. This work aims to investigate the crude glycerol pretreatment method and then apply the glycerol as a co-substrate with pig manure for anaerobic digestion. The optimum crude glycerol pretreatment method was acidification with 6% of H2SO4 that highest glycerol recovery was obtained with lowest cost. Co-digestions of glycerol and pig manure enhanced biogas and methane productions compared with mono-digestions. Biogas and methane productions in semi-continuous digestions were highly effected by OLR. The optimum OLR was 3.06 kg SCOD/m3 that biogas production was maintained at 3 L/d with methane composition of 72% and SCOD removal higher than 80%.

  10. 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

    This study critically evaluates the biological processes and techniques applied to remove nitrogen and phosphorus from the anaerobic supernatant produced from the treatment of the organic fraction of municipal solid waste (OFMSW) and from its co-digestion with other biodegradable organic waste (BOW) streams. The wide application of anaerobic digestion for the treatment of several organic waste streams results in the production of high quantities of anaerobic effluents. Such effluents are characterized by high nutrient content, because organic and particulate nitrogen and phosphorus are hydrolyzed in the anaerobic digestion process. Consequently, adequate post-treatment is required in order to comply with the existing land application and discharge legislation in the European Union countries. This may include physicochemical and biological processes, with the latter being more advantageous due to their lower cost. Nitrogen removal is accomplished through the conventional nitrification/denitrification, nitritation/denitritation and the complete autotrophic nitrogen removal process; the latter is accomplished by nitritation coupled with the anoxic ammonium oxidation process. As anaerobic digestion effluents are characterized by low COD/TKN ratio, conventional denitrification/nitrification is not an attractive option; short-cut nitrogen removal processes are more promising. Both suspended and attached growth processes have been employed to treat the anaerobic supernatant. Specifically, the sequencing batch reactor, the membrane bioreactor, the conventional activated sludge and the moving bed biofilm reactor processes have been investigated. Physicochemical phosphorus removal via struvite precipitation has been extensively examined. Enhanced biological phosphorus removal from the anaerobic supernatant can take place through the sequencing anaerobic/aerobic process. More recently, denitrifying phosphorus removal via nitrite or nitrate has been explored. The removal of

  11. Electrolysis-enhanced anaerobic digestion of wastewater.

    Science.gov (United States)

    Tartakovsky, B; Mehta, P; Bourque, J-S; Guiot, S R

    2011-05-01

    This study demonstrates enhanced methane production from wastewater in laboratory-scale anaerobic reactors equipped with electrodes for water electrolysis. The electrodes were installed in the reactor sludge bed and a voltage of 2.8-3.5 V was applied resulting in a continuous supply of oxygen and hydrogen. The oxygen created micro-aerobic conditions, which facilitated hydrolysis of synthetic wastewater and reduced the release of hydrogen sulfide to the biogas. A portion of the hydrogen produced electrolytically escaped to the biogas improving its combustion properties, while another part was converted to methane by hydrogenotrophic methanogens, increasing the net methane production. The presence of oxygen in the biogas was minimized by limiting the applied voltage. At a volumetric energy consumption of 0.2-0.3 Wh/L(R), successful treatment of both low and high strength synthetic wastewaters was demonstrated. Methane production was increased by 10-25% and reactor stability was improved in comparison to a conventional anaerobic reactor.

  12. Microbial electrochemical monitoring of volatile fatty acids during anaerobic digestion

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Jin, Xiangdan; Angelidaki, Irini

    2015-01-01

    Due to increasing environmental concerns of using fossil fuels and decreasing in their reserves, the promotion of renewable energy technologies is crucial. Anaerobic digestion (AD), a well-developed technology converting organic waste into biogas, is gaining increased attention in recent years...... desalination cell, MDC) was built to realize the on-line measuring the concentration of volatile fatty acid (VFA). The correlation between current densities of the biosensor and VFA concentrations was firstly evaluated with synthetic digestate. Two linear relationships were observed between current densities...

  13. The Effect of the Addition of Active Digester Effluent for Start-up Accelerator in Anaerobic Digestion of Soybean Curd Industry Waste Water (Basic Research for Biogas Power Generation

    Directory of Open Access Journals (Sweden)

    Arini Wresta

    2012-12-01

    Full Text Available Biogas production from soybean curd industry waste water was studied in laboratory scale to improve the application of anaerobic digestion process. The problem with the soybean curd waste water was the fact that it does not sufficiently contain anaerobic microorganisms required in biogas production. Therefore, it is necessary to add a well-developed population of anaerobic microorganisms to accelerate the start-up of the anerobic digestion. This research was aimed to verify the influence of the addition of active digester effluent into the soybean curd waste water batches in an anaerobic digestion process. Batch experiments were done in two digesters. The first digester was only fed with soybean curd waste water while the second digester was fed with soybean curd waste water and active digester effluent from a digester processing cow manure which was very rich in anaerobic microorganism consortium. The results indicated that soybean curd industry waste water did not contain methanogenic bacteria but there existed some acidogenic bacteria. The addition of active digester effluent accelerated the anaerobic digestion start-up and directed the process pathway towards methanogenic process so that more methane was obtained. The high methane content obtained (more than 64% volume was very potential for power generation. The capacity of soybean curd industry must be as high as 697.13 kg soybean per day to generate the electric energy of 8.4 kWh.

  14. Principles and potential of the anaerobic digestion of waste-activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Appels, Lise; Degreve, Jan [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. De Croylaan 46, B-3001 Heverlee (Belgium); Baeyens, Jan [Department of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Dewil, Raf [Department of Chemical Engineering, Katholieke Universiteit Leuven, W. De Croylaan 46, B-3001 Heverlee (Belgium); Department of Chemical Engineering, Associated Faculty of Technology and Biosciences, Campus De Nayer, Katholieke Universiteit Leuven, Jan De Nayerlaan 5, B-2860 Sint-Katelijne-Waver (Belgium)

    2008-12-15

    When treating municipal wastewater, the disposal of sludge is a problem of growing importance, representing up to 50% of the current operating costs of a wastewater treatment plant. Although different disposal routes are possible, anaerobic digestion plays an important role for its abilities to further transform organic matter into biogas (60-70 vol% of methane, CH{sub 4}), as thereby it also reduces the amount of final sludge solids for disposal whilst destroying most of the pathogens present in the sludge and limiting odour problems associated with residual putrescible matter. Anaerobic digestion thus optimises WWTP costs, its environmental footprint and is considered a major and essential part of a modern WWTP. The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade quality and to enhance energy use. The present paper extensively reviews the principles of anaerobic digestion, the process parameters and their interaction, the design methods, the biogas utilisation, the possible problems and potential pro-active cures, and the recent developments to reduce the impact of the problems. After having reviewed the basic principles and techniques of the anaerobic digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognised as rate-limiting step in the complex digestion process. The microbiology of anaerobic digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions. As will be shown, these groups are sensitive to and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids and others. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include

  15. Utilization of vegetable dumplings waste from industrial production by anaerobic digestion

    Science.gov (United States)

    Pilarska, Agnieszka A.; Pilarski, Krzysztof; Ryniecki, Antoni; Tomaszyk, Kamila; Dach, Jacek; Wolna-Maruwka, Agnieszka

    2017-01-01

    This paper provides the analysis of results of biogas and methane yield for vegetable dumplings waste: dough with fat, vegetable waste, and sludge from the clarifier. Anaerobic digestion of food waste used in the experiments was stable after combining the substrates with a digested pulp composed of maize silage and liquid manure (as inoculum), at suitable ratios. The study was carried out in a laboratory scale using anaerobic batch reactors, at controlled (mesophilic) temperature and pH conditions. The authors present the chemical reactions accompanying biodegradation of the substrates and indicate the chemical compounds which may lead to acidification during the anaerobic digestion. An anaerobic digestion process carried out with the use of a dough-and-fat mixture provided the highest biogas and methane yields. The following yields were obtained in terms of fresh matter: 242.89 m3 Mg-1 for methane and 384.38 m3 Mg-1 for biogas, and in terms of volatile solids: 450.73 m3 Mg-1 for methane and 742.40 m3 Mg-1 for biogas. Vegetables and sludge from the clarifier (as fresh matter) provided much lower yields.

  16. Anaerobic digestion of aircraft deicing fluid wastes: interactions and toxicity of corrosion inhibitors and surfactants.

    Science.gov (United States)

    Gruden, Cyndee L; Hernandez, Mark

    2002-01-01

    Corrosion inhibitors and surfactants are present in aircraft deicing fluids (ADFs) at significant concentrations (> 1% w/w). The purpose of this research was to study the interactions of a common nonionic surfactant with the commercially significant corrosion inhibitors used in modern ADF (4- and 5-methylbenzotriazole [MeBT]), and to determine the effects of their mixture on the conventional anaerobic digestion process. In mesophilic anaerobic microcosms codigesting wastewater solids, propylene glycol, and MeBT, increasing surfactant levels resulted in enhanced MeBT sorption on digester solids. As judged by anaerobic toxicity assays, responses from digesters containing surfactant concentrations below their critical micelle concentration (CMC) suggested that low nonionic surfactant concentrations could facilitate a reduction in the apparent toxicity of MeBT. In microcosms exposed to surfactant concentrations above their CMC, no increase in MeBT solubility was observed, and the anaerobic toxicity response corresponded to control systems not containing surfactant. Direct microscopic measurements of digesting biomass using fluorescent phylogenetic probes (fluorescent in situ hybridization) revealed that members of the domain Bacteria were more sensitive to MeBT in the presence of surfactant than were members of the domain Archaea.

  17. Manual of procedures for the operation of bench-scale anaerobic digesters

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, R.R.

    1978-12-01

    The successful operation of any laboratory-scale biological system is often a difficult and frustrating experience. This is especially true when dealing with the anaerobic digestion process. Because of the stringent environmental requirements associated with anaerobic digesters, efficient operation of bench-scale units requires rigid monitoring and control. The purpose of this manual is to present the methods and procedures which are followed in bench-scale anaerobic digestion studies at Pacific Northwest Laboratory (PNL). Among the topics discussed are operating parameters, a description of the experimental system, typical digestion substrates, operational procedures, analytical techniques, and safety considerations. The document serves as a technical guide to PNL personnel assigned to a U.S. Department of Energy sponsored program evaluating the effect of powdered activated carbon on the anaerobic digestio of sewage sludge. It should be noted that the methods described in this manual do not necessarily represent the best or only means of conducting the research. They are merely procedures that have been found to be successful at PNL. It is hoped that this information may be useful to other researchers who are contemplating or pursuing bench-scale studies of their own.

  18. Treatment of melanoidin wastewater by anaerobic digestion and coagulation.

    Science.gov (United States)

    Arimi, Milton M; Zhang, Yongjun; Götz, Gesine; Geißen, Sven-Uwe

    2015-01-01

    Melanoidins are dark-coloured recalcitrant pollutants found in many industrial wastewaters including coffee-manufacturing effluent, molasses distillery wastewater (MDWW) and other wastewater with molasses as the raw material. The wastewaters are mostly treated with anaerobic digestion after some dilution to minimize the inhibition effect. However, the dark colour and recalcitrant dissolved organic carbon (DOC) mainly caused by melanoidin are not effectively removed. The aim of this study was to investigate the removal of colour and remnant DOC by different coagulants from anaerobically digested MDWW. From the six coagulants tested, ferric chloride had the highest melanoidin (48%), colour (92.7%) and DOC (63.3%) removal at pH 5 and a dosage of 1.6 g/l. Both polymer and inorganic salt coagulants tested had optimal colour, melanoidin and DOC removal at acidic pH. The molecular size distribution of synthetic melanoidins by liquid chromatography-organic carbon detection indicated a preferential removal of high-molecular-weight melanoidins over low weight melanoidins by the coagulation. Further studies should focus on how to improve biodegradability of the treated effluent for it to be reused as dilution water for anaerobic digestion.

  19. Pathogen inactivation in liquid dairy manure during anaerobic and aerobic digestions

    Science.gov (United States)

    Biswas, S.; Pandey, P.; Castillo, A. R.; Vaddella, V. K.

    2014-12-01

    Controlling manure-borne pathogens such as E. coli O157:H7, Salmonella spp. and Listeria monocytogenes are crucial for protecting surface and ground water as well as mitigating risks to human health. In California dairy farms, flushing of dairy manure (mainly animal feces and urine) from freestall barns and subsequent liquid-solid manure separation is a common practice for handling animal waste. The liquid manure fraction is generally pumped into the settling ponds and it goes into aerobic and/or anaerobic lagoons for extended period of time. Considering the importance of controlling pathogens in animal waste, the objective of the study was to understand the effects of anaerobic and aerobic digestions on the survival of three human pathogens in animal waste. The pathogen inactivation was assessed at four temperatures (30, 35, 42, and 50 °C), and the relationships between temperature and pathogen decay were estimated. Results showed a steady decrease of E. coli levels in aerobic and anaerobic digestion processes over the time; however, the decay rates varied with pathogens. The effect of temperature on Salmonella spp. and Listeria monocytogenes survival was different than the E. coli survival. In thermophilic temperatures (42 and 50 °C), decay rate was considerable greater compared to the mesophilic temperatures (30 and 35°C). The E. coli log reductions at 50 °C were 2.1 in both aerobic and anaerobic digestions after 13 days of incubation. The Salmonella spp. log reductions at 50 °C were 5.5 in aerobic digestion, and 5.9 in anaerobic digestion. The Listeria monocytogenes log reductions at 50 °C were 5.0 in aerobic digestion, and 5.6 in anaerobic digestion. The log reduction of E. coli, Salmonella spp., and Listeria monocytogens at 30 °C in aerobic environment were 0.1, 4.7, and 5.6, respectively. In anaerobic environment, the corresponding reductions were 0.4, 4.3, and 5.6, respectively. We anticipate that the outcomes of the study will help improving the

  20. Variation of ADM1 by using temperature-phased anaerobic digestion (TPAD) operation.

    Science.gov (United States)

    Lee, Myung-Yeol; Suh, Chang-Won; Ahn, Yong-Tae; Shin, Hang-Sik

    2009-06-01

    The objective of the study was to examine the application of the Anaerobic Digestion Model No. 1 (ADM1) developed by the IWA task group for mathematical modelling of anaerobic process. Lab-scale temperature-phased anaerobic digestion (TPAD) process were operated continuously, and were fed with co-substrate composed of dog food and flour. The model platform implemented in the simulation was a derivative of the ADM1. Sensitivity analysis showed that k(m.process) (maximum specific uptake rate) and K(S.process) (half saturation value) had high sensitivities to model components. Important parameters including maximum uptake rate for propionate utilisers (k(m.pro)) and half saturation constant for acetate utilisers (K(S.ac)) in the thermophilic digester and maximum uptake rate for acetate utilisers (k(m.ac)) in the mesophilic digester were estimated using iterative methods, which optimized the parameters with experimental results. Simulation with estimated parameters showed good agreement with experimental results in the case of methane production, uptake of acetate, soluble chemical oxygen demand (SCOD) and total chemical oxygen demand (TCOD). Under these conditions, the model predicted reasonably well the dynamic behavior of the TPAD process for verifying the model.

  1. Biogas production as affected by heavy metals in the anaerobic digestion of sludge

    Directory of Open Access Journals (Sweden)

    Hussein I. Abdel-Shafy

    2014-12-01

    The sewage sludge samples were separated from the sewage water of the pilot plant at the National Research Centre, TDC site. The effect of heavy metals on the biogas production of the anaerobic digester was studied. The inhibitory effect on the biogas production and toxic level of metals was determined in this study. The general ranking of heavy metal toxicity appears to be Hg > Cd > Cr (III. The present investigation reveals that heavy metals in addition to the anaerobic digester decreased the biogas production as an indication of efficiency of the process. A significant decrease in gas production and volatile organic matter removal was obtained. It was also noted that an accumulation of organic acid intermediates was obtained as a result of methanogenic bacterial inhibition. This accumulation was limited during the pulse feed of metals. This is due to the rapid poisoning of the active bacterial forms in the digester.

  2. 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.

  3. 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.

  4. 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...

  5. Autogenerative high pressure digestion: anaerobic digestion and biogas upgrading in a single step reactor system

    NARCIS (Netherlands)

    Lindeboom, R.E.F.; Fermoso, F.G.; Weijma, J.; Zagt, K.; Lier, van J.B.

    2011-01-01

    Conventional anaerobic digestion is a widely applied technology to produce biogas from organic wastes and residues. The biogas calorific value depends on the CH4 content which generally ranges between 55 and 65%. Biogas upgrading to so-called ‘green gas’, with natural gas quality, generally proceeds

  6. Performance and Analysis of Floating dome Anaerobic Digester with Wet and Dry Feedstock

    Science.gov (United States)

    Sathish, S.; Parthiban, A.; Venugopal, S.; Jothi Prakash, V. M.

    2017-03-01

    The objective of this study is to evaluate the feasibility of anaerobic digestion to generate biogas yield and it’s performed using wet and dry feed stock. The laboratory experiment is conducted in a floating dome type anaerobic digester with 1m3 capacity. It is made up of fibre material at continues process. The starter cowdung used as an inoculum of the anaerobic digester. Then raw materials feeded as a wet type wheat straw and dry type wheat straw is the ratio of 1:1 waste/water in both the experiments wet and dry wheat straw. In this experiments are fermented at 30ºC to 35ºC temperature is maintained. The daily biogas yield, cumulative biogas yield, pH, CH4, and hydro retention time these parameters is studied and analysed. The maximum daily biogas is 25liters and 42% of methane is achieved in dry wheat straw at 15th day of digestion. The highest gas yield obtained in dry condition compare to wet condition and acid level also decreased in wet digestion.

  7. Agro-industrial anaerobic digestion cost benefits: Technology utilization in distillery; Aspetti economici della digestione anaerobica nell`agroindustria: Applicazione di una nuova tecnologia in una distilleria

    Energy Technology Data Exchange (ETDEWEB)

    De Poli, F.; Mela, E.; Pasqualini, S.

    1991-02-01

    Anaerobic digestion, followed by aerobic post treatment, is widely used as a treatment technology of distillery wastes. An economic comparison between two different treatment processes; a traditional concentration unit and the termophilic hybrid anaerobic digester, was done. The costs/benefits balance shows the strong advantage of the anaerobic process, even if the value of by-products from the concentrator is higher than the ones from the digester; the operation costs (mainly labour and energy) of the concentrator are strongly higher, and the balance becomes negative. The NPV of the two plants shows always negative values for the concentrator, while the digester can become convenient under some conditions.

  8. Influence of phenylacetic acid pulses on anaerobic digestion performance and archaeal community structure in WWTP sewage sludge digesters

    NARCIS (Netherlands)

    Cabrol, L.; Urra, J.; Rosenkranz, F.; Kroff, P.A.; Plugge, C.M.; Lesty, Y.; Chamy, R.

    2015-01-01

    The effect of phenylacetic acid (PAA) pulses on anaerobic digestion (AD) performance and archaeal community structure was evaluated in anaerobic digesters treating sewage sludge from a wastewater treatment plant (WWTP). Four pilot-scale continuous stirred tank reactors were set up at a full-scale mu

  9. A methane production feasibility model for central anaerobic digesters

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, J.L. (Western Ontario University, London, Canada); Peters, N. (Fundacao de Tecnologia Industrial, Botafogo, Brazil)

    1981-01-01

    A mathematical model was developed for prediction of the practicability of building and operating large centrally located anaerobic digesters for producing methane gas from animal manure. The assumptions were that the manure would be collected from the feedlots and that the product gas would be supplied to an existing pipeline. The model takes account of the farm locations and calculates transportation costs for various numbers of digesters. Digester sizes for each distribution and installation and operating costs are computed. Revenue was then determined on the basis of methane production and fertilizer value recovery. The utility of the model is shown through a study of farms in southwestern Ontario where many small feedlots exist. The results of the study indicate a gas production cost of roughly $0.18/cu m.

  10. Elucidation of the thermophilic phenol biodegradation pathway via benzoate during the anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Hoyos-Hernandez, Carolina; Hoffmann, Marieke; Guenne, Angeline; Mazeas, Laurent

    2014-02-01

    Anaerobic digestion makes it possible to valorize municipal solid waste (MSW) into biogas and digestate which are, respectively, a renewable energy source and an organic amendment for soil. Phenols are persistent pollutants present in MSW that can inhibit the anaerobic digestion process and have a toxic effect on microbiota if they are applied to soil together with digestate. It is then important to define the operational conditions of anaerobic digestion which allow the complete degradation of phenol. In this context, the fate of phenol during the anaerobic digestion of MSW at 55°C was followed using an isotopic tracing approach ((13)C6-phenol) in experimental microcosms with inoculum from an industrial thermophilic anaerobic digester. With this approach, it was possible to demonstrate the complete phenol biodegradation into methane and carbon dioxide via benzoate. Benzoate is known to be a phenol metabolite under mesophilic conditions, but in this study it was found for the first time to be a phenol degradation product at thermophilic temperature.

  11. Digesters and demographics: identifying support for anaerobic digesters on dairy farms.

    Science.gov (United States)

    Sanders, D J; Roberts, M C; Ernst, S C; Thraen, C S

    2010-11-01

    The dairy industry in the United States is amidst a long-running trend toward fewer, larger dairy farms. This development has created a backlash in some communities over concerns such as odor, waste management, and environmental degradation. Separately, anaerobic digestion has advanced as a waste management technology that potentially offers solutions to some of these issues, providing odor control and a combustible biogas among other things. These digesters require significant capital investments. Voluntary consumer premiums for the renewable energy produced have been used in some instances as a means to move adoption of such systems toward financial feasibility. This project employed a survey to measure Ohio consumers' willingness to pay a premium for renewable energy produced by anaerobic digesters on dairy farms. Cluster analysis was used to segment consumers by willingness to pay, age, education, income, self-identified political inclination, and a composite variable that served as a proxy for respondents' environmental stewardship. Four distinctive groups emerged from the data. Older, less educated respondents were found to have the least amount of support for digesters on dairy farms, whereas politically liberal, environmentally proactive respondents demonstrated the strongest support. Well-educated, affluent respondents and young respondents fell between these 2 groups. Most large dairy farms are generally met with fairly negative responses from their local communities; in contrast, this research finds some popular support for anaerobic digestion technology. Going forward, establishing a positive link between support for anaerobic digesters and for their use on large dairies could open up a new route for less-contested large dairy farm developments. Evaluation of community demographics could become an important part of finding an optimal location for a large dairy farm.

  12. Anaerobic digestion as a key technology in bio-energy production: Current achievements and challenges

    OpenAIRE

    Dewil, Raf; Appels, Lise

    2014-01-01

    Anaerobic digestion has been applied for many decades for the treatment of organic wastes like manure, wastewater sludge and crop residues. Whereas these streams were considered as a nuisance in the past, nowadays, emphasis lies on resource recovery. These wastes are, indeed, providing an important source of renewable energy. Therefore, there is a renewed interest in anaerobic digestion as a technology for sustainable renewable energy production. Also, anaerobic digestion plays a central role...

  13. Growth and anaerobic digestion characteristics of microalgae cultivated using various types of sewage.

    Science.gov (United States)

    Hidaka, Taira; Inoue, Kenichiro; Suzuki, Yutaka; Tsumori, Jun

    2014-10-01

    Microalgal cultivation combined with anaerobic digestion at wastewater treatment plants is promising to recover energy. This study investigated the growth and anaerobic digestion characteristics of microalgae cultivated using nutrients in sewage. Microalgae were cultivated using primary effluent, secondary effluent, and dewatering filtrate. Microscopic observation indicated that Chlorella was cultivated using dewatering filtrate of anaerobic digestion without controlling the type of species. Batch anaerobic digestion experiments with digested sludge showed that the methane conversion ratio of the cultivated mixture was approximately 40-65%. Different cultivation time did not affect the microalgal contents. Methane recovery mass was 0.13NL-methane/L-cultivation liquor. The C/N ratio of the cultivated mixture was approximately 3-5, but the apparent ammonia release ratio was smaller than that of sewage sludge during digestion. These results proved the applicability of methane recovery from microalgae cultivated using nutrients included in anaerobically digested sludge.

  14. [Anaerobic co-digestion of corn stalk and vermicompost].

    Science.gov (United States)

    Chen, Guang-yin; Zheng, Zheng; Zou, Xing-xing; Fang, Cai-xia; Luo, Yan

    2010-02-01

    The characteristics of corn stalk digested alone at different total solid (TS) loading rates and co-digestion of various proportions of corn stalk and vermicompost were investigated by batch model at 35 degrees C +/- 1 degrees C. The organic loading rates (OLRs) studied were in the range of 1.2%-6.0% TS and increasing proportions of vermicompost from 20% to 80% TS. A maximum methane yield of corn stalk digested alone was 217.60 mL/g obtained at the TS loading rate of 4.8%. However, when the TS loading rate was 6.0%, the anaerobic system was acidified and the lowest pH value was 5.10 obtained on day 4 and the biogas productivity decreased. Furthermore, co-digestion of vermicompost and corn stalk in varying proportions were investigated at constant of 6.0% TS. Co-digestion with vermicompost improved the biodegradability of corn stalk and the methane yield was improved by 4.42%-58.61%, and led to higher pH values, higher volatile fatty acids (VFAs) concentration and lower alkalinity content compared with corn stalk digested alone. The maximum biogas yield and methane yield of 410.30 mL/g and 259. 35 mL/g were obtained for 40% vermicompost and 60% corn stalk respectively. Compared with corn stalk digested alone, co-digested with vermicompost didn' t affect methane content and the fermentation type, but promoted the destruction of crystalline of cellulose and the highest destruction rate was 29.36% for 40% vermicompost and 60% corn stalk. Therefore, adding vermicompost was beneficial for the decomposition and increasing the biotransformation rate of corn stalk.

  15. Improving anaerobic sewage sludge digestion by implementation of a hyper-thermophilic prehydrolysis step

    DEFF Research Database (Denmark)

    Lu, Jingquan; Gavala, Hariklia N.; Skiadas, Ioannis V.;

    2008-01-01

    at a HRT of 13 days. A one-step anaerobic digester operated at 55 degrees C and 15 days HRT Was used as a reference process. The two-step process was characterized by a 12% higher organic suspended solids removal efficiency and better pathogen reduction effect than the conventional one-step digestion......The present study focuses on a two-step process for treatment and stabilisation of primary sludge. The process consists of a hyperthermophilic hydrolysis step operated at 70 degrees C and a hydraulic retention time (HRT) of 2 clays followed by a thermophilic (55 degrees C) anaerobic digestion step....... The microbial community of the digester fed with pre-treated sludge was characterised by it higher activity compared to that of the digester treating raw sludge. Moreover, the pre-treatment of the primary sludge resulted up to 48% increase of the methane potential (20.09 and 13.56 mmol CH4 g(-)VS(-1...

  16. Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

    Science.gov (United States)

    Ali Shah, Fayyaz; Mahmood, Qaisar; Maroof Shah, Mohammad; Pervez, Arshid; Ahmad Asad, Saeed

    2014-01-01

    Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed. PMID:24701142

  17. Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis

    Directory of Open Access Journals (Sweden)

    Fayyaz Ali Shah

    2014-01-01

    Full Text Available Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization that deal with taxonomy and interaction and distribution of tropic groups used are also discussed.

  18. Treatment of separated piggery anaerobic digestate liquid using woodchip biofilters.

    Science.gov (United States)

    Carney, K N; Rodgers, M; Lawlor, P G; Zhan, X

    2013-01-01

    The Irish nitrates directive restricts the land area suitable for landspreading of pig manure, so anaerobic digestion warrants consideration. In this study, six identical Lodgepole pine woodchip biofilters were set up to treat the separated liquid fraction of digestate after anaerobic digestion of pig manure. Two hydraulic loading rates were examined: 5 L/m2/d (LLR) and 10 L/m2/d (HLR). Following a start-up period of 70 days, an average of 90% and 71% of NH4(+)-N was removed at LLR and HLR, respectively. LLR resulted in higher total nitrogen removals than HLR (p biofilter effluent. A batch experiment testing the capacity of saturated woodchips in removing total oxidized nitrogen (TON) from the effluent of the woodchip biofilters showed that TON was reduced by 323 mg/L from 663 mg/L in 360 h, indicating that the aerobic woodchip biofilters should incorporate a saturated layer ofwoodchips at the base ofthe biofilters to enhance nitrogen removal.

  19. Behaviour of emerging contaminants in sewage sludge after anaerobic digestion.

    Science.gov (United States)

    Boix, C; Ibáñez, M; Fabregat-Safont, D; Morales, E; Pastor, L; Sancho, J V; Sánchez-Ramírez, J E; Hernández, F

    2016-11-01

    Nowadays, there is an increasing concern over the presence of contaminants in the aquatic environment, where they can be introduced from wastewater after their incomplete removal in the treatment plants. In this work, degradation of selected emerging pollutants in the aqueous and solid phases of sewage sludge has been investigated after anaerobic digestion using two different digesters: mesophilic and thermophilic. Initially, sludge samples were screened by ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS) for identification of emerging contaminants in the samples. In a second step, a target quantitative method based on LC coupled to tandem MS was applied for selected pollutants identified in the previous screening. The behaviour of the compounds under anaerobic conditions was studied estimating the degradation efficiency and distribution of compounds between both sludge phases. Irbesartan and benzoylecgonine seemed to be notably degraded in both phases of the sludge. Venlafaxine showed a significant concentration decrease in the aqueous phase in parallel to an increase in the solid phase. The majority of the compounds showed an increase of their concentrations in both phases after the digestion. Concentrations in the solid phase were commonly higher than in the aqueous for most contaminants, indicating that they were preferentially adsorbed onto the solid particles.

  20. Hydrolytic activity of alpha-amylase in anaerobic digested sludge.

    Science.gov (United States)

    Higuchi, Y; Ohashi, A; Imachi, H; Harada, H

    2005-01-01

    Hydrolysis is usually considered to be a rate-limiting step in anaerobic digestion. For improving anaerobic solid waste treatments, it is essential to elucidate the mechanism of hydrolysis. In this study, alpha-amylase, one of the hydrolytic enzymes, was investigated for the elucidation of more precise mechanism of hydrolysis. Alpha-amylase activity of solid starch-degrading bacteria (SDB) was estimated through batch experiments with several different substrates and with distinction between cell-bound and cell-free alpha-amylase. Monitoring of newly isolated strains of SDB was done by fluorescence in situ hybridization. Results indicated that cell-bound alpha-amylase is chiefly responsible for the hydrolysis in the digested sludge, providing very useful information that the contact between microbial cells and solids is significantly important. The activity of alpha-amylase of the digested sludge remained quite low when not required, but increased as they recognized appropriate substrates. Several-fold higher activity was obtained for starch or maltose as compared to glucose only.

  1. 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.

  2. Modelling the rheological properties of sludge during anaerobic digestion in a batch reactor by using electrical measurements.

    Science.gov (United States)

    Dieudé-Fauvel, E; Héritier, P; Chanet, M; Girault, R; Pastorelli, D; Guibelin, E; Baudez, J C

    2014-03-15

    Anaerobic digestion is a significant process leading to biogas production and waste management. Despite this double interest, professionals still face a lack of efficient tools to monitor and manage the whole procedure. This is especially true for rheological properties of the material inside the reactor, which are of major importance for anaerobic digestion management. However, rheological properties can hardly be determined in-situ and it would be very helpful to determine indicators of their evolution. To solve this problem, this paper investigates the evolution of sewage sludge rheological and electrical properties during the anaerobic digestion in a batch reactor. We especially focus on apparent viscosity and complex impedance, measured by electrical impedance spectroscopy. Both of them can be modelled by a linear combination of raw sludge and inoculum properties, weighted by time-dependent coefficients. Thus, by determining digested sludge electrical signature, it is possible to obtain those coefficients and model sludge apparent viscosity. This work offers many theoretical and practical prospects.

  3. Anaerobic digestion of slaughterhouse by-products

    DEFF Research Database (Denmark)

    Hejnfelt, Anette; Angelidaki, Irini

    2009-01-01

    giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm(-3) and 7 gN dm(-3) respectively. Pretreatment (pasteurization: 70 degrees C, sterilization: 133 degrees C, and alkali...

  4. Evaluation of high-solids anaerobic digestion process for converting excess sludge to biogas%应用高固体浓度厌氧消化工艺转化污泥产沼气研究

    Institute of Scientific and Technical Information of China (English)

    刘晓玲; 李十中; 刘建双; 李天成; 王莉

    2011-01-01

    应用高固体浓度厌氧消化工艺在中温(35±1)℃条件下,考察了进料总固体(TS)含量为17%的污泥在5 L反应器中批式厌氧消化产沼气的发酵过程,并探讨了高固体浓度厌氧消化工艺转化污泥产沼气的可行性.结果表明,沼气和CH4的累积产量在整个厌氧消化期间(73 d)经历产气高峰、相对稳定和结束3个阶段,累积产气量分别达121.3 L和80.3 L,且在产气相对稳定阶段,CH4的含量保持相对稳定,平均为70.7%;虽然总酸、乙酸、丙酸和氨氮在消化阶段最高分别达9.5 g·L-1、4.8 g·L-1、2.6 g·L-1和3653 mg·L-1,但沼气和甲烷的产量在厌氧消化过程中并未受到明显的影响.同时,应用高固体浓度厌氧消化工艺可显著提高有效容积沼气产率和有效容积CH4产率,它们在厌氧消化期间的产率平均分别可达0.498 L·L-1·d-1与0.330 L·L-1·d-1,且厌氧消化结束后总固体和有机质(VS)去除率分别为44.2%和67.3%.%Laboratory-scale evaluation of a high-solids anaerobic digestion process for converting excess sludge to biogas was performed in this study. The batch experiment was carried out in a developed anaerobic reactor (5.0 L), which operated at mesophilic (35 ± 1 ) ℃ and high-solids ( 17% total solids)conditions. Excess sludge exhibited a methanogenic pattern including fast biogae production phase, relatively stable phase and final phase through the whole experimental period (73 days) and this gave cumulative biogas of 121.3 L and cumulative bio-methane of 80.3 L. The content of bio-methane stayed relatively stable during the relatively stable operation phase, and its mean value accounted for 70.7%. Although total volatile fatty acids, acetic acid, propionic acid and ammonia nitrogen significantly increased to 9.5 g· L - 1 ,4.8 g· L - 1 ,2.6 g· L - 1 and 3653 mg· L - 1, respectively, they had no obvious impact on the production of biogae and bio-methane during the anaerobic digestion. The

  5. Influence of steam explosion pretreatment on the anaerobic digestion of vinegar residue.

    Science.gov (United States)

    Feng, Jiayu; Zhang, Jiyu; Zhang, Jiafu; He, Yanfeng; Zhang, Ruihong; Liu, Guangqing; Chen, Chang

    2016-07-01

    Vinegar residue is the by-product in the vinegar production process. The large amount of vinegar residue has caused a serious environmental problem owing to its acidity and corrosiveness. Anaerobic digestion is an effective way to convert agricultural waste into bioenergy, and a previous study showed that vinegar residue could be treated by anaerobic digestion but still had room to improve digestion efficiency. In this study, steam explosion at pressure of 0.8, 1.2, and 1.5 MPa and residence time of 5, 10, 15, and 20 min were used to pretreat vinegar residue to improve methane production, respectively. Scanning electron microscopy and X-ray diffraction analyses were applied to validate structural changes of vinegar residue after steam explosion. Results showed that steam explosion pretreatment could destroy the structure of lignocellulose by removing the hemicellulose and lignin, and improve the methane yield effectively. Steam explosion-treated vinegar residue at 0.8 MPa for 5 min produced the highest methane yield of 153.58 mL gVS (-1), which was 27.65% (significant, α steam explosion did not influence the stability of anaerobic digestion. This study suggested that steam explosion pretreatment on vinegar residue might be a promising approach and it is worth further study to improve the efficiency of vinegar residue waste utilisation.

  6. Microbial community structure and dynamics during anaerobic digestion of various agricultural waste materials.

    Science.gov (United States)

    Ziganshin, Ayrat M; Liebetrau, Jan; Pröter, Jürgen; Kleinsteuber, Sabine

    2013-06-01

    The influence of the feedstock type on the microbial communities involved in anaerobic digestion was investigated in laboratory-scale biogas reactors fed with different agricultural waste materials. Community composition and dynamics over 2 months of reactors' operation were investigated by amplicon sequencing and profiling terminal restriction fragment length polymorphisms of 16S rRNA genes. Major bacterial taxa belonged to the Clostridia and Bacteroidetes, whereas the archaeal community was dominated by methanogenic archaea of the orders Methanomicrobiales and Methanosarcinales. Correlation analysis revealed that the community composition was mainly influenced by the feedstock type with the exception of a temperature shift from 38 to 55 °C which caused the most pronounced community shifts. Bacterial communities involved in the anaerobic digestion of conventional substrates such as maize silage combined with cattle manure were relatively stable and similar to each other. In contrast, special waste materials such as chicken manure or Jatropha press cake were digested by very distinct and less diverse communities, indicating partial ammonia inhibition or the influence of other inhibiting factors. Anaerobic digestion of chicken manure relied on syntrophic acetate oxidation as the dominant acetate-consuming process due to the inhibition of aceticlastic methanogenesis. Jatropha as substrate led to the enrichment of fiber-degrading specialists belonging to the genera Actinomyces and Fibrobacter.

  7. Anaerobic alkaline digestion of sewage sludge. 4. ed. Anaerobe alkalische Schlammfaulung

    Energy Technology Data Exchange (ETDEWEB)

    Roediger, H.; Roediger, M.; Kapp, H.

    1990-01-01

    The book presents a historical outline, the biological and chemical processes, measures for intensivation and disinfestation, and for dimensioning and installation of sewage sludge digestion systems. (EF).

  8. 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.

  9. 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

  10. Stability Analysis of Some Nonlinear Anaerobic Digestion Models

    Directory of Open Access Journals (Sweden)

    Ivan Simeonov

    2010-04-01

    Full Text Available Abstract: The paper deals with local asymptotic stability analysis of some mass balance dynamic models (based on one and on two-stage reaction schemes of the anaerobic digestion (AD in CSTR. The equilibrium states for models based on one (with Monod, Contois and Haldane shapes for the specific growth rate and on two-stage (only with Monod shapes for both the specific growth rate of acidogenic and methanogenic bacterial populations reaction schemes have been determined solving sets of nonlinear algebraic equations using Maples. Their stability has been analyzed systematically, which provides insight and guidance for AD bioreactors design, operation and control.

  11. Deploying anaerobic digesters: Current status and future possibilities

    Energy Technology Data Exchange (ETDEWEB)

    Lusk, P. [International Energy Agency, Paris (France); Wheeler, P. [ETSU (United Kingdom); Rivard, C. [National Renewable Energy Lab., Golden, CO (United States)

    1996-01-01

    Unmanaged pollutants from putrescible farm, industrial, and municipal wastes degrade in the environment, and methane emitted from their decomposition may contribute to global climate change. Under modern environmental regulations, these wastes are becoming difficult to dispose of using traditional means. One waste management system, anaerobic digestion or AD, not only provides pollution prevention but can also convert a disposal problem into a new profit center. This report is drawn from a special session of the Second Biomass Conference of the Americas. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  12. The future of anaerobic digestion and biogas utilisation

    DEFF Research Database (Denmark)

    Holm-Nielsen, Jens Bo; Al Seadi, Teodorita; Oleskowicz-Popiel, Piotr

    2009-01-01

    , representing a considerable pollution threat for the environment in these areas. Avoiding over-fertilization is not only important for environmental protection reasons but also for economical reasons. Intensive animal production areas need therefore suitable manure management, aiming to export...... and to redistribute the excess of nutrients from manure and to optimize their recycling. Anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel - the biogas. The EU policies concerning renewable...

  13. Potential use of the organic fraction of municipal solid waste in anaerobic co-digestion with wastewater in submerged anaerobic membrane technology.

    Science.gov (United States)

    Moñino, P; Jiménez, E; Barat, R; Aguado, D; Seco, A; Ferrer, J

    2016-10-01

    Food waste was characterized for its potential use as substrate for anaerobic co-digestion in a submerged anaerobic membrane bioreactor pilot plant that treats urban wastewater (WW). 90% of the particles had sizes under 0.5mm after grinding the food waste in a commercial food waste disposer. COD, nitrogen and phosphorus concentrations were 100, 2 and 20 times higher in food waste than their average concentrations in WW, but the relative flow contribution of both streams made COD the only pollutant that increased significantly when both substrates were mixed. As sulphate concentration in food waste was in the same range as WW, co-digestion of both substrates would increase the COD/SO4-S ratio and favour methanogenic activity in anaerobic treatments. The average methane potential of the food waste was 421±15mLCH4g(-1)VS, achieving 73% anaerobic biodegradability. The anaerobic co-digestion of food waste with WW is expected to increase methane production 2.9-fold. The settleable solids tests and the particle size distribution analyses confirmed that both treatment lines of a conventional WWTP (water and sludge lines) would be clearly impacted by the incorporation of food waste into its influent. Anaerobic processes are therefore preferred over their aerobic counterparts due to their ability to valorise the high COD content to produce biogas (a renewable energy) instead of increasing the energetic costs associated with the aeration process for aerobic COD oxidation.

  14. [Anaerobic co-digestion of RSU and macro-algae in the Venice lagoon. Preliminary results].

    Science.gov (United States)

    Cecchi, F; Pavan, P; Bassetti, A; Farneti, A; Barbaresi, U

    1991-01-01

    In these last few years in the lagoon of Venice the phenomenon of eutrophization has increased. The possibility of turning to an anaerobic digestion of the biomass seems to be interesting. In this view, the following experiment describes a study on the co-digestion of mechanically selected algaebiomass and organic fraction of solid urban waste. The results relevant to both yield parameters and process stability are reported, which have been obtained by monitoring a 3 m3 pilot digestor during a running period of about 85 days, under different working conditions.

  15. 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).

  16. Methane and hydrogen production from crop biomass through anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Pakarinen, O.

    2011-07-01

    The feasibility of methane and hydrogen production from energy crops through anaerobic digestion was evaluated in this thesis. The effects of environmental conditions, e.g. pH and temperature, as well as inoculum source on H{sub 2} yield were studied in batch assays. In addition, the effects of pre-treatments on methane and hydrogen yield as well as the feasibility of two-stage H{sub 2} + CH{sub 4} production was evaluated. Moreover, the effect of storage on methane yield of grasses was evaluated. Monodigestion of grass silage for methane production was studied, as well as shifting the methanogenic process to hydrogenic. Hydrogen production from grass silage and maize was shown to be possible with heat-treated inoculum in batch assays, with highest H{sub 2} yields of 16.0 and 9.9 ml gVS{sub added}-1 from untreated grass silage and maize, respectively. Pre-treatments (NaOH, HCl and water-extraction) showed some potential in increasing H{sub 2} yields, while methane yields were not affected. Two-stage H{sub 2} + CH{sub 4} producing process was shown to improve CH{sub 4} yields when compared to traditional one-stage CH{sub 4} process. Methane yield from grass silage monodigestion in continuously stirred tank reactor (CSTR) with organic loading rate (OLR) of 2 kgVS (m3d)-1 and hydraulic retention time (HRT) of 30 days was at most 218 l kgVS{sub fed}-1. Methanogenic process was shifted to hydrogenic by increasing the OLR to 10 kgVS (m3d)-1 and shortening the HRT to 6 days. Highest H{sub 2} yield from grass silage was 42 l kgVS{sub fed}-1 with a maximum H{sub 2} content of 24 %. Energy crops can be successfully stored even for prolonged periods without decrease in methane yield. However, under sub-optimal storage conditions loss in volatile solids (VS) content and methane yield can occur. According to present results energy crops such as grass silage and maize can be converted to hydrogen or methane in AD process. Hydrogen energy yields are typically only 2-5 % of the

  17. Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

    Science.gov (United States)

    Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

    2016-05-15

    Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology.

  18. Environmental assessment of farm-scaled anaerobic co-digestion for bioenergy production.

    Science.gov (United States)

    Lijó, Lucía; González-García, Sara; Bacenetti, Jacopo; Negri, Marco; Fiala, Marco; Feijoo, Gumersindo; Moreira, María Teresa

    2015-07-01

    The aim of this study was to assess the environmental profile of a bioenergy system based on a co-digestion plant using maize silage and pig slurry as substrates. All the processes involved in the production of bioenergy as well as the avoided processes accrued from the biogas production system were evaluated. The results evidenced the environmental importance of the cultivation step and the environmental credits associated to the avoided processes. In addition, this plant was compared with two different plants that digest both substrates separately. The results revealed the environmental benefits of the utilisation of pig slurry due to the absence of environmental burdens associated with its production as well as credits provided when avoiding its conventional management. The results also presented the environmental drawbacks of the utilisation of maize silage due to the environmental burdens related with its production. Accordingly, the anaerobic mono-digestion of maize silage achieved the worst results. The co-digestion of both substrates was ranked in an intermediate position. Additionally, three possible digestate management options were assessed. The results showed the beneficial effect of digestate application as an organic fertiliser, principally on account of environmental credits due to avoided mineral fertilisation. However, digestate application involves important acidifying and eutrophicating emissions.

  19. Composting of solids separated from anaerobically digested animal manure

    DEFF Research Database (Denmark)

    Chowdhury, Md Albarune; de Neergaard, Andreas; Jensen, Lars Stoumann

    2014-01-01

    We investigated the effects of bulking agents (BA) and mixing ratios on greenhouse gas (GHG) and NH3 emissions from composting digested solids (DS), separated from anaerobically digested manure and other bio-wastes, in small-scale laboratory composters. BA evaluated were plastic tube pieces (PT......), woodchips (WC), bio-char (BC), barley straw (BS) and lupin residues (LR) and were included at a DS:BA of 3:1 or 6:1, resulting in nine treatments: CTDS (control, DS only), PT3:1, PT6:1, WC3:1, WC6:1, BC3:1, BC6:1, BS3:1 and LR3:1. Depending on treatment, C losses via CO2 and CH4 emissions accounted for 41...

  20. Reduction in greenhouse gas emissions from vinasse through anaerobic digestion

    DEFF Research Database (Denmark)

    Moraes, Bruna S.; Petersen, Søren O.; Zaiat, Marcelo;

    2017-01-01

    Vinasse is a residue from bioethanol production that is produced in large quantities in Brazil and Europe and is applied to fields as a source of plant nutrients (fertirrigation). A side effect of this use is greenhouse gas (GHG) emissions during storage and transport in open channels to fields......, and from fertirrigated soils. This study assessed GHG emissions in experiments simulating this vinasse management system, and the potential for reducing emissions of methane (CH4) and nitrous oxide (N2O) from vinasse via anaerobic digestion (AD) in biogas plants. During 21 days’ storage of untreated...... with digestate, ranging from 0.173 to 0.193 kg CO2eq m−2 in the former and from 0.045 to 0.100 kg CO2eq m−2 in the latter. Extrapolation of the results to a Brazilian case indicated that AD treatment prior to storage/transport and field application could reduce GHG emissions from the vinasse management chain...

  1. Treatment of urban residential organic waste through anaerobic digestion

    Directory of Open Access Journals (Sweden)

    Fabiane Granzotto

    2016-10-01

    Full Text Available The amount of waste generated nowadays is a reflection of population growth and consumerism, many times, unnecessary by people. Organic waste is the most part of the solid waste generated. This waste need to be treated adequately to avoid environmental problems and health problems in people. The objective was to treat urban residential organic waste and to verify the efficiency of the transformation into biogas and bio fertilizers. A digester of the Indian type was used in Nova Palma, Rio Grande do Sul. The research was developed in the period of three years with a daily monitoring. The average biogas production was higher in the summer for three years and it was more stable in the third year in different seasons. There were no reagents to coliforms. The study found that anaerobic digestion has potential in treating organic waste.

  2. Anaerobic digestion of macroalgae: methane potentials, pre-treatment, inhibition and co-digestion

    DEFF Research Database (Denmark)

    Bangsø Nielsen, Henrik; Heiske, Stefan

    2011-01-01

    for Chaetomorpha linum and 340 ml g VS1 for Saccharina latissima following 34 days of incubation. With an organic content of 21.1% (1.5–2.8 times higher than the other algae) S. latissima seems very suitable for anaerobic digestion. However, the methane yields of U. lactuca, G. vermiculophylla and C. linum could...... be increased with 68%, 11% and 17%, respectively, by pretreatment with maceration. U. lactuca is often observed during ‘green tides’ in Europe and has a high cultivation potential at Nordic conditions. Therefore, U. lactuca was selected for further investigation and co-digested with cattle manure in a lab...

  3. Progress in Anaerobic Digestion Models%国内外厌氧消化模型研究进展

    Institute of Scientific and Technical Information of China (English)

    杨双春; 邓丹; 梁丹丹; 潘一

    2012-01-01

    The anaerobic biological method is a process of low energy consumption and high efficiency to deal with high concentration organic wastewater. An anaerobic digestion model describes how the bacteria and the facultative anaerobic bacteria decompose the biodegradable organic in the sludge into carbon dioxide, methane and water under anaerobic conditions. As a structure model, it contains all procedures, including the production processes of decomposition and hydrolysis, acid, acetic acid and methane. In this paper, some sludge anaerobic digestion models are reviewed, such as the single-phase anaerobic digestion model (SP- ADM1), the Two-Phase Anaerobic Digestion Model (TP-ADM1), the combination of the Anaerobic Digestion and the Activated Sludge (ADM1-ASMs), the Sulfate Reduction of Anaerobic Digestion Model (SR-ADM1), the Nitrate Reduction of Anaerobic Digestion Expansion Model (NR-ADEM1), the Gas Production and its Expansion of the Anaerobic Digestion Model (GPAE-ADM1), the Sedimentation Tank of Anaerobic Digestion Model (ST-ADM1), and the Inhibition Kinetics of Anaerobic Digestion Model (IK-ADM1). In addition, the anaerobic digestion models are evaluated in comparison with the anaerobic digestion model 1, and some suggestions are made for future researches .%厌氧生物法是一种适用于处理高浓度有机废水的高效低能耗的处理工艺,厌氧消化模型是表述兼性细菌和厌氧细菌将可生物降解的有机物分解成二氧化碳、甲烷和水的过程模型.它是一个具有分解和水解、产酸、产乙酸和产甲烷等过程的复杂的结构化模型.本文主要介绍了国内外污泥厌氧消化模型的研究现状及其进展,模型包括厌氧消化1号模型(ADM1)、好氧活性污泥-厌氧消化模型(ASM1-ADM1)、单相中温-厌氧消化模型(SPMT-ADM1)、单相高温-厌氧消化模型(SPHT-ADM1)、两相-厌氧消化模型(TP-ADM1)、厌氧消化-活性污泥复合模型(ADM1 -ASMs)、硫酸盐

  4. ADM1-based modeling of anaerobic digestion of swine manure fibers pretreated with aqueous ammonia soaking

    DEFF Research Database (Denmark)

    Jurado, Esperanza; Gavala, Hariklia N.; Skiadas, Ioannis

    2012-01-01

    that the AAS had on the efficiency of the anaerobic digestion of manure. Kinetic parameters were estimated by fitting of the model to data from manure fed digesters. The model was able to satisfactorily simulate the behaviour of digesters fed with manure. However, the model predictions were poorer...... fibers. In the present study, mesophilic anaerobic digestion of AAS pretreated manure fibers was tested in CSTR-type digesters fed with swine manure and/or a mixture of swine manure and AAS pretreated manure fibers. The Anaerobic Digestion Model No.1 (ADM1) was used for the prediction of the effect......Anaerobic digestion of manure fibers present challenges due to their low biodegradability. Aqueous ammonia soaking (AAS) and subsequent ammonia removal has been tested as a simple and cheap method to disrupt the lignocellulose and increase the methane potential and the biogas productivity of manure...

  5. Anaerobic digestion of antibiotic residue in combination with hydrothermal pretreatment for biogas.

    Science.gov (United States)

    Zhang, Guangyi; Li, Chunxing; Ma, Dachao; Zhang, Zhikai; Xu, Guangwen

    2015-09-01

    Antibiotic residues are difficult to be treated or utilized because of their high water content and residual antibiotics. This article is devoted to investigating the possibility of biogas production from cephalosporin C residue (CPCAR), one typical type of antibiotic residues, via anaerobic digestion in combination with hydrothermal pretreatment (HTPT). The results from the bench-scale experiments showed that the combination of HTPT and anaerobic digestion can provide a viable way to convert CPCAR into biogas, and the biogas and methane yields reached 290 and 200 ml(g TS)(-1), respectively. This article further evaluated the proposed technology in terms of energy balance and technical feasibility based on theoretical calculation using the data from a pilot HTPT test. It was shown that the process is totally self-sufficient in energy and its main challenging problem of ammonia inhibition can be solved via ammonia stripping.

  6. Enhancement of Taihu blue algae anaerobic digestion efficiency by natural storage.

    Science.gov (United States)

    Miao, Hengfeng; Lu, Minfeng; Zhao, Mingxing; Huang, Zhenxing; Ren, Hongyan; Yan, Qun; Ruan, Wenquan

    2013-12-01

    Taihu blue algae after different storage time from 0 to 60 d were anaerobic fermented to evaluate their digestibility and process stability. Results showed that anaerobic digestion (AD) of blue algae under 15 d natural storage led to the highest CH4 production of 287.6 mL g(-1) VS at inoculum substrate ratio 2.0, demonstrating 36.69% improvement comparing with that from fresh algae. Storage of blue algae led to cell death, microcystins (MCs) release and VS reduction by spontaneous fermentation. However, it also played an important role in removing algal cell wall barrier, pre-hydrolysis and pre-acidification, leading to the improvement in CH4 yield. Closer examination of volatile fatty acids (VFA) variation, VS removal rates and key enzymes change during AD proved short storage time (≤ 15 d) of blue algae had higher efficiencies in biodegradation and methanation. Furthermore, AD presented significant biodegradation potential for MCs released from Taihu blue algae.

  7. Temperature regulates methane production through the function centralization of microbial community in anaerobic digestion.

    Science.gov (United States)

    Lin, Qiang; De Vrieze, Jo; He, Guihua; Li, Xiangzhen; Li, Jiabao

    2016-09-01

    Temperature is crucial for the performance of anaerobic digestion process. In this study of anaerobic digestion of swine manure, the relationship between the microbial gene expression and methane production at different temperatures (25-55°C) was revealed through metatranscriptomic analysis. Daily methane production and total biogas production increased with temperature up to 50°C, but decreased at 55°C. The functional gene expression showed great variation at different temperatures. The function centralization (opposite to alpha-diversity), assessed by the least proportions of functional pathways contributing for at least 50% of total reads positively correlated to methane production. Temperature regulated methane production probably through reducing the diversity of functional pathways, but enhancing central functional pathways, so that most of cellular activities and resource were invested in methanogenesis and related pathways, enhancing the efficiency of conversion of substrates to methane. This research demonstrated the importance of function centralization for efficient system functioning.

  8. 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.

  9. Start-up performances of dry anaerobic mesophilic and thermophilic digestions of organic solid wastes

    Institute of Scientific and Technical Information of China (English)

    LU Shu-guang; IMAI Tsuyoshi; UKITA Masao; SEKINE Masahiko

    2007-01-01

    Two dry anaerobic digestions of organic solid wastes were conducted for 6 weeks in a lab-scale batch experiment for investigating the start-up performances under mesophilic and thermophilic conditions. The enzymatic activities,i.e., β-glucosidase, β-glucosidase, N-α -benzoyl-L-argininamide (BAA)-hydrolysing protease, urease and phosphatase activities were analysed. The lower BAA-hydrolysing protease activity during the first 2-3 weeks was due to the inhibition of the low pH, but was enhanced simultaneously later with the pH increase. β-glucosidase activity showed the lowest values in weeks 1-2, and recovered simultaneously with the increase of BAA-hydrolysing protease activity. Acetic acid dominated most of the total VFAs in thermophilic digestion, while propionate and butyrate dominated in mesophilic digestion. Thermophilic digestion is confirmed more feasible for achieving better performance against misbalance, especially during the start-up period in a dry anaerobic digestion process.

  10. Anaerobic digestion of waste waters after washing olives used for oil production: in fluence of harvest time on the kinetics of the process. Digestion anaerobia de las aguas de lavado de aceitunas de almazara: influencia del periodo de recoleccion sobre la cinetica del proceso

    Energy Technology Data Exchange (ETDEWEB)

    Borja-Padilla, R.; Alba-Mendoza, J.; Hidalgo-Casado, F.

    1994-01-01

    A kinetic study was carried out of anaerobic digestion of waste waters after washing olives used for oil production, collected at three different harvest times (December 1992, January and February 1993). A 1-litre mixed batch bioreactor operated at 35 degree centigree and containing a sepiolite-immobilized biomass was used. Assuming that the overall anaerobic digestion process conforms to a first-order kinetics, experimental data pairs, namely methane volume yield (G) and time (t), fit Roediger's equation, from which the rate coefficient values, k[sub o], were determined in each of the situations studied. The rate coefficient considerably decreased with the harvest time, over the substrate concentration range studied (0.5-2.5 g COD/1). The average values obtained were [sub 1.67],[sub 1.13] and [sub 0.75] days for the waste waters corresponding to the three harvest times considered. Also, the methanogenic activity decreased with the ripening of the olives; the observed differences increased when the substrate concentration in the digester increased. The coefficients of methane yield, Yp ranged between 0.263 (first harvest time) and 0.298 I CH[sub 4]/g COD removed (third harvest time). The elimination of COD exceeded 64% in all cases. (Author) 13 refs.

  11. Single-phase and two-phase anaerobic digestion of fruit and vegetable waste: Comparison of start-up, reactor stability and process performance

    Energy Technology Data Exchange (ETDEWEB)

    Ganesh, Rangaraj [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Torrijos, Michel, E-mail: michel.torrijos@supagro.inra.fr [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Sousbie, Philippe [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France); Lugardon, Aurelien [Naskeo Environnment, 52 rue Paul Vaillant Couturier, F-92240 Malakoff (France); Steyer, Jean Philippe; Delgenes, Jean Philippe [INRA, UR50, Laboratoire de Biotechnologie de l’Environnement, Avenue des Etangs, Narbonne F-11100 (France)

    2014-05-01

    Highlights: • Single-phase and two-phase systems were compared for fruit and vegetable waste digestion. • Single-phase digestion produced a methane yield of 0.45 m{sup 3} CH{sub 4}/kg VS and 83% VS removal. • Substrate solubilization was high in acidification conditions at 7.0 kg VS/m{sup 3} d and pH 5.5–6.2. • Energy yield was lower by 33% for two-phase system compared to the single-phase system. • Simple and straight-forward operation favored single phase process over two-phase process. - Abstract: Single-phase and two-phase digestion of fruit and vegetable waste were studied to compare reactor start-up, reactor stability and performance (methane yield, volatile solids reduction and energy yield). The single-phase reactor (SPR) was a conventional reactor operated at a low loading rate (maximum of 3.5 kg VS/m{sup 3} d), while the two-phase system consisted of an acidification reactor (TPAR) and a methanogenic reactor (TPMR). The TPAR was inoculated with methanogenic sludge similar to the SPR, but was operated with step-wise increase in the loading rate and with total recirculation of reactor solids to convert it into acidification sludge. Before each feeding, part of the sludge from TPAR was centrifuged, the centrifuge liquid (solubilized products) was fed to the TPMR and centrifuged solids were recycled back to the reactor. Single-phase digestion produced a methane yield of 0.45 m{sup 3} CH{sub 4}/kg VS fed and VS removal of 83%. The TPAR shifted to acidification mode at an OLR of 10.0 kg VS/m{sup 3} d and then achieved stable performance at 7.0 kg VS/m{sup 3} d and pH 5.5–6.2, with very high substrate solubilization rate and a methane yield of 0.30 m{sup 3} CH{sub 4}/kg COD fed. The two-phase process was capable of high VS reduction, but material and energy balance showed that the single-phase process was superior in terms of volumetric methane production and energy yield by 33%. The lower energy yield of the two-phase system was due to the loss of

  12. Repeated pulse feeding induces functional stability in anaerobic digestion.

    Science.gov (United States)

    De Vrieze, Jo; Verstraete, Willy; Boon, Nico

    2013-07-01

    Anaerobic digestion is an environmental key technology in the future bio-based economy. To achieve functional stability, a minimal microbial community diversity is required. This microbial community should also have a certain 'elasticity', i.e. the ability to rapidly adapt to suboptimal conditions or stress. In this study it was evaluated whether a higher degree of functional stability could be achieved by changing the feeding pattern, which can change the evenness, dynamics and richness of the bacterial community. The first reactor (CSTR stable ) was fed on daily basis, whereas the second reactor (CSTR dynamic ) was fed every 2 days. Average biogas production was 0.30 l CH4 l(-1) day(-1) in both reactors, although daily variation was up to four times higher in the CSTR dynamic compared with the CSTR stable during the first 50 days. Bacterial analysis revealed that this CSTR dynamic had a two times higher degree of bacterial community dynamics. The CSTR dynamic also appeared to be more tolerant to an organic shock load of 8 g COD l(-1) and ammonium levels up to 8000 mg TAN l(-1). These results suggest that the regular application of a limited pulse of organic material and/or a variation in the substrate composition might promote higher functional stability in anaerobic digestion.

  13. Thermochemical Pretreatment for Anaerobic Digestion of Sorted Waste

    Science.gov (United States)

    Hao, W.; Hongtao, W.

    2008-02-01

    The effect of alkaline hydrothermal pre-treatment for anaerobic digestion of mechanically-sorted municipal solid waste (MSW) and source-sorted waste was studied. Waste was hydrothermally pre-treated in dilute alkali solution. Hydrolysis product was incubated in 500 ml saline bottle to determine methane potential (MP) under mesospheric anaerobic conditions. Optimum reaction condition obtained in the study is 170 °C at the dose of 4 g NaOH/100 g solid for one hour. Soluble COD was 13936 mg/L and methane yield was 164 ml/g VS for 6 days incubation at optimum conditions. More than 50% biogas increase was achieved over the control, and methane conversion ratio on carbon basis was enhanced to 30.6%. The digestion period was less than 6 days when pre-treatment temperature was above 130 °C. The organic part of sorted waste is mainly constituted of kitchen garbage and leaf. Model kitchen garbage was completely liquidized at 130 °C for one hour and the methane yield was 276 ml/g VS. Addition of alkali enhance hydroxylation rate and methane yield slightly. The biogas potential of leaf could be observed by pre-treatment above 150 °C under alkaline condition.

  14. Evaluation and characterization during the anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor.

    Science.gov (United States)

    Xiao, Xiaolan; Huang, Zhenxing; Ruan, Wenquan; Yan, Lintao; Miao, Hengfeng; Ren, Hongyan; Zhao, Mingxing

    2015-10-01

    The anaerobic digestion of high-strength kitchen waste slurry via a pilot-scale anaerobic membrane bioreactor (AnMBR) was investigated at two different operational modes, including no sludge discharge and daily sludge discharge of 20 L. The AnMBR provided excellent and reliable permeate quality with high COD removal efficiencies over 99%. The obvious accumulations of long chain fatty acids (LCFAs) and Ca(2+) were found in the anaerobic digester by precipitation and agglomeration. Though the physicochemical process contributed to attenuating the free LCFAs toxicity on anaerobic digestion, the digestion efficiency was partly influenced for the low bioavailability of those precipitates. Moreover, higher organic loading rate (OLR) of 5.8 kg COD/(m(3) d) and digestion efficiency of 78% were achieved as the AnMBR was stably operated with sludge discharge, where the membrane fouling propensity was also alleviated, indicating the crucial significance of SRT control on the treatment of high-strength kitchen waste slurry via AnMBRs.

  15. Anaerobic co-digestion of aquatic flora and quinoa with manures from Bolivian Altiplano.

    Science.gov (United States)

    Alvarez, René; Lidén, Gunnar

    2008-01-01

    Quinoa stalk (Chenopodium quinoa Willd.) from agricultural crop residue, totora (Schoenoplectus tatora) and o-macrophytes (aquatic flora) from Lake Titicaca (on the Bolivian Altiplano) were studied in a wet anaerobic co-digestion process together with manure from llama, cow and sheep. Anaerobic semi-continuous experiments were performed in (10) 2-l reactors at a temperature of 25 degrees C with 30 days of hydraulic retention time (HRT) and an organic loading rate (OLR) of 1.8 kg VS m(-3) d(-1). Totora was found to be the best co-substrate. In mixture ratios of 1:1 (VS basis), it increased the biogas productivity by 130% for llama manure, 60% for cow manure, and 40% for sheep manure. It was possible to use up to 58% (VS basis) of totora in the substrate. Higher concentrations (including pure totora) could not be digested, as that caused acidification problems similar to those caused by other lignocellulosic materials. When quinoa and o-macrophytes were used as co-substrates, the increase in biogas productivity was slightly less. However, these co-substrates did not cause any operational problems. An additional advantage of quinoa and o-macrophytes was that they could be used in any proportion (even in pure form) without causing any destabilization problems in the anaerobic digestion process.

  16. Dry anaerobic digestion of the organic fraction of municipal solid waste.

    NARCIS (Netherlands)

    ten Brummeler, E.

    1993-01-01

    Anaerobic digestion is an attractive technology for solid waste management. This thesis describes the technological potentials of dry anaerobic digestion of the organic fraction of Municipal Solid Waste (MSW) using batch systems. In 1985 a research programme was started to develop the so- called BIO

  17. 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...

  18. Evaluation of biogas production by dry anaerobic digestion of switchgrass-animal manure mixtures

    Science.gov (United States)

    Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application without adverse environmental effects. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion (> 15% TS; total solid) has an advantage ov...

  19. Speciation modeling of ammonia and other major solutes in anaerobic digesters

    Science.gov (United States)

    Anaerobic digestion of high-nitrogen wastes can be inhibited by high concentrations of un-ionized ammonia, NH**3 (aq). Understanding the toxicity of NH**3 (aq) to anaerobic digestion requires an understanding of the mechanisms controlling its concentration. Previous work on ammonia toxicity in an...

  20. [Municipal biowaste thermal-hydrolysis and ASBR anaerobic digestion].

    Science.gov (United States)

    Hou, Hua-hua; Wang, Wei; Hu, Song; Xu, Yi-xian

    2010-02-01

    Thermal-hydrolysis can remarkably improve the solid organics dissolving efficiency of urban biomass waste, and anaerobic sequencing batch reactor (ASBR) was used to improve the efficiency of urban biomass waste anaerobic digestion. The optimum thermal-hydrolysis temperature and holding time was 175 degrees C and 60 min, the volatile suspended solid (VSS) dissolving ratio of kitchen waste, fruit-and-vegetable waste and sludge were 31.3%, 31.9% and 49.7%, respectively. Two ASBR and one continuous-flow stirred tank reactor (CSTR) were started at hydraulic retention time (HRT) = 20 d, COD organic loading rate (OLR) = 3.2-3.6 kg/(m3 x d). The biogas production volumes were 5656 mL/d(A1), 6335 mL/d(A2) and 3 103 mL/d(CSTR), respectively; VSS degradation ratios were 45.3% (A1), 50.87% (A2), 20.81% (CSTR), and the total COD (TCOD) removal rates were 88.1% (A1), 90% (A2), 72.6% (CSTR). In ASBR, organic solid and anaerobic microorganism were remained in the reactor during settling period. When HRT was 20 d, the solid retention time (SRT) was over 130 d, which made ASBR higher efficiency than CSTR.

  1. Anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure in a single continuously stirred tank reactor process: Limits in co-substrate ratios and organic loading rate.

    Science.gov (United States)

    Rico, Carlos; Muñoz, Noelia; Rico, José Luis

    2015-01-01

    Mesophilic anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure was investigated with the aim of determining the treatment limits in terms of the cheese whey fraction in feed and the organic loading rate. The results of a continuous stirred tank reactor that was operated with a hydraulic retention time of 15.6 days showed that the co-digestion process was possible with a cheese whey fraction as high as 85% in the feed. The efficiency of the process was similar within the range of the 15-85% cheese whey fraction. To study the effect of the increasing loading rate, the HRT was progressively shortened with the 65% cheese whey fraction in the feed. The reactor efficiency dropped as the HRT decreased but enabled a stable operation over 8.7 days of HRT. At these operating conditions, a volumetric methane production rate of 1.37 m(3) CH4 m(-3) d(-1) was achieved.

  2. Impact of sludge thickening on energy recovery from anaerobic digestion[Held jointly with the 4. Canadian organic residuals and biosolids managment conference

    Energy Technology Data Exchange (ETDEWEB)

    Puchajda, B. [Stantec Consulting Ltd., Winnipeg, MB (Canada); Oleszkiewicz, J. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Civil Engineering

    2007-07-01

    The anaerobic digestion of wastewater sludge leads to production of a biogas mixture of methane and carbon dioxide. The technology of anaerobic digestion has been applied in various configurations and generally claims greater biogas production and additional stability to the process as compared to conventional mesophilic anaerobic digestion. However, biogas production is only one of many components of anaerobic digester energy balance. This paper presented energy balances for various digestion systems, including single mesophilic digestion; single thermophilic digestion; two-stage thermophilic-mesophilic digestion; and systems at elevated solids content in sludge. Energy balance included two components, namely energy demand and recoverable energy. Energy demand is defined as energy required for process operation such as heat requirement to elevate sludge temperature, and heat losses through digesters walls. Recoverable energy is defined as energy associated with methane content in biogas, that can be recovered either in the form of heat or electricity, and heat recovered through heat exchangers. The paper identified the assumptions used in all energy balance calculations. It presented the objectives and methods of the study as well as the results. It was concluded that two-stage thermophilic-mesophilic digestion system generate more available energy than single mesophilic digestion and single thermophilic digestion systems. Sludge thickening offers the greatest amount of available energy. However, that energy surplus is offset by the cost of thickening. 12 refs., 3 tabs., 6 figs.

  3. 微氧通气对厌氧消化产气中硫化氢的去除的研究%Removal of Hydrogen Sulphide in the Process of Anaerobic Digestion of Sludge by Micro-oxygen Ventilation

    Institute of Scientific and Technical Information of China (English)

    罗珠; 安明哲; 苏建; 刘阳; 张富勇; 彭智辅; 赵东; 刘胜敏; 苟梓希; 刘莉

    2016-01-01

    High concentration of H2S produced in anaerobic digestion of sludge from liquor-making was removed by micro-oxygen ventilation as follows:COD removal rate remained between 90%~98%, ventilation volume was within 7%~16%of bio-gas yield, COD loading in-creased from 1.25 g/L·d up to 5.0 g/L·d, the average bio-gas productivity increased up to 200~250 mL/g-COD, methane concentration re-mained 40%~60%(v/v), and the concentration of H2S was controlled under 500 mg/L.The results showed that, micro-oxygen ventilation was an effective method to remove H2S in the process of anaerobic digestion of sludge.%采用微氧通气的方法去除酿酒综合废水在厌氧消化阶段产气中产生的高浓度的H2S。将COD负荷从1.25 g/L·d提升至5.0 g/L·d,通气量在产气量体积比的7%~16%范围内,COD降解率保持在90%~98%之间,单位产气量增至200~250 mL/g-COD;甲烷浓度保持在40%~60%之间,H2S浓度控制在50 mg/L以下。结果表明,利用微氧通气去除厌氧消化产气中的H2S是一种很有效的方法。

  4. 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

  5. Life cycle assessment of energy from waste via anaerobic digestion: a UK case study.

    Science.gov (United States)

    Evangelisti, Sara; Lettieri, Paola; Borello, Domenico; Clift, Roland

    2014-01-01

    Particularly in the UK, there is potential for use of large-scale anaerobic digestion (AD) plants to treat food waste, possibly along with other organic wastes, to produce biogas. This paper presents the results of a life cycle assessment to compare the environmental impacts of AD with energy and organic fertiliser production against two alternative approaches: incineration with energy production by CHP and landfill with electricity production. In particular the paper investigates the dependency of the results on some specific assumptions and key process parameters. The input Life Cycle Inventory data are specific to the Greater London area, UK. Anaerobic digestion emerges as the best treatment option in terms of total CO2 and total SO2 saved, when energy and organic fertiliser substitute non-renewable electricity, heat and inorganic fertiliser. For photochemical ozone and nutrient enrichment potentials, AD is the second option while incineration is shown to be the most environmentally friendly solution. The robustness of the model is investigated with a sensitivity analysis. The most critical assumption concerns the quantity and quality of the energy substituted by the biogas production. Two key issues affect the development and deployment of future anaerobic digestion plants: maximising the electricity produced by the CHP unit fuelled by biogas and to defining the future energy scenario in which the plant will be embedded.

  6. Seasonal Variation on Microbial Community and Methane Production during Anaerobic Digestion of Cattle Manure in Brazil.

    Science.gov (United States)

    Resende, Juliana Alves; Godon, Jean-Jacques; Bonnafous, Anaïs; Arcuri, Pedro Braga; Silva, Vânia Lúcia; Otenio, Marcelo Henrique; Diniz, Cláudio Galuppo

    2016-04-01

    Anaerobic digestion is an alternative method for the treatment of animal manure and wastewater. The anaerobic bioconversion of biomass requires a multi-step biological process, including microorganisms with distinct roles. The diversity and composition of microbial structure in pilot-scale anaerobic digestion operating at ambient temperature in Brazil were studied. Influence of the seasonal and temporal patterns on bacterial and archaeal communities were assessed by studying the variations in density, dynamic and diversity and structure. The average daily biogas produced in the summer and winter months was 18.7 and 16 L day(-1), respectively, and there was no difference in the average methane yield. Quantitative PCR analysis revealed that no differences in abundances and dynamics were found for bacterial communities and the total number of Archaea in different seasons. Analysis of bacterial clone libraries revealed a predominance of Firmicutes (54.5 %/summer and 46.7 %/winter) and Bacteroidetes (31.4 %/summer and 44.4 %/winter). Within the Archaea, the phylum Euryarchaeota was predominant in both digesters. Phylogenetic distribution showed changes in percentage between the phyla identified, but no alterations were recorded in the quality and amount of produced methane or community dynamics. The results may suggest that redundancy of microbial groups may have occurred, pointing to a more complex microbial community in the ecosystem related to this ambient temperature system.

  7. Nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.

    Science.gov (United States)

    Song, Yong-Hui; Qiu, Guang-Lei; Yuan, Peng; Cui, Xiao-Yu; Peng, Jian-Feng; Zeng, Ping; Duan, Liang; Xiang, Lian-Cheng; Qian, Feng

    2011-06-15

    Anaerobically digested swine wastewater contains high concentrations of phosphorus (P) and nitrogen (N). A pilot-scale experiment was carried out for nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization. In the pilot plant, a sequencing batch reactor (SBR) and a continuous-flow reactor with struvite accumulation devices were designed and employed. The wastewater pH value was increased by CO(2) stripping, and the struvite crystallization process was performed without alkali and Mg(2+) additions. Results of the long-term operation of the system showed that, both reactors provided up to 85% P removal and recovery over wide ranges of aeration times (1.0-4.0 h), hydraulic retention times (HRT) (6.0-15.0 h) and temperatures (0-29.5°C) for an extended period of 247 d, in which approximate 30% of P was recovered by the struvite accumulation devices. However, 40-90% of NH(4)(+)-N removed was through air stripping instead of being immobilized in the recovered solids. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite with purity of more than 90%. This work demonstrated the feasibility and effects of nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.

  8. Biogas energy production from tropical biomass wastes by anaerobic digestion.

    Science.gov (United States)

    Ge, Xumeng; Matsumoto, Tracie; Keith, Lisa; Li, Yebo

    2014-10-01

    Anaerobic digestion (AD) is an attractive technology in tropical regions for converting locally abundant biomass wastes into biogas which can be used to produce heat, electricity, and transportation fuels. However, investigations on AD of tropical forestry wastes, such as albizia biomass and food wastes, such as taro, papaya, and sweet potato, are limited. In this study, these tropical biomass wastes were evaluated for biogas production by liquid AD (L-AD) and/or solid-state AD (SS-AD), depending on feedstock characteristics. When albizia leaves and chips were used as feedstocks, L-AD had greater methane yields (161 and 113 L kg(-1)VS, respectively) than SS-AD (156.8 and 59.6 L kg(-1)VS, respectively), while SS-AD achieved 5-fold higher volumetric methane productivity than L-AD. Mono-digestion and co-digestion of taro skin, taro flesh, papaya, and sweet potato achieved methane yields from 345 to 411 L kg(-1)VS, indicating the robustness of AD technology.

  9. Optimising the anaerobic co-digestion of urban organic waste using dynamic bioconversion mathematical modelling.

    Science.gov (United States)

    Fitamo, T; Boldrin, A; Dorini, G; Boe, K; Angelidaki, I; Scheutz, C

    2016-12-01

    Mathematical anaerobic bioconversion models are often used as a convenient way to simulate the conversion of organic materials to biogas. The aim of the study was to apply a mathematical model for simulating the anaerobic co-digestion of various types of urban organic waste, in order to develop strategies for controlling and optimising the co-digestion process. The model parameters were maintained in the same way as the original dynamic bioconversion model, albeit with minor adjustments, to simulate the co-digestion of food and garden waste with mixed sludge from a wastewater treatment plant in a continuously stirred tank reactor. The model's outputs were validated with experimental results obtained in thermophilic conditions, with mixed sludge as a single substrate and urban organic waste as a co-substrate at hydraulic retention times of 30, 20, 15 and 10 days. The predicted performance parameter (methane productivity and yield) and operational parameter (concentration of ammonia and volatile fatty acid) values were reasonable and displayed good correlation and accuracy. The model was later applied to identify optimal scenarios for an urban organic waste co-digestion process. The simulation scenario analysis demonstrated that increasing the amount of mixed sludge in the co-substrate had a marginal effect on the reactor performance. In contrast, increasing the amount of food waste and garden waste resulted in improved performance.

  10. Single-phase and two-phase anaerobic digestion of fruit and vegetable waste: comparison of start-up, reactor stability and process performance.

    Science.gov (United States)

    Ganesh, Rangaraj; Torrijos, Michel; Sousbie, Philippe; Lugardon, Aurelien; Steyer, Jean Philippe; Delgenes, Jean Philippe

    2014-05-01

    Single-phase and two-phase digestion of fruit and vegetable waste were studied to compare reactor start-up, reactor stability and performance (methane yield, volatile solids reduction and energy yield). The single-phase reactor (SPR) was a conventional reactor operated at a low loading rate (maximum of 3.5 kgVS/m3 d), while the two-phase system consisted of an acidification reactor (TPAR) and a methanogenic reactor (TPMR). The TPAR was inoculated with methanogenic sludge similar to the SPR, but was operated with step-wise increase in the loading rate and with total recirculation of reactor solids to convert it into acidification sludge. Before each feeding, part of the sludge from TPAR was centrifuged, the centrifuge liquid (solubilized products) was fed to the TPMR and centrifuged solids were recycled back to the reactor. Single-phase digestion produced a methane yield of 0.45 m3 CH4/kg VS fed and VS removal of 83%. The TPAR shifted to acidification mode at an OLR of 10.0 kgVS/m3 d and then achieved stable performance at 7.0 kgVS/m3 d and pH 5.5-6.2, with very high substrate solubilization rate and a methane yield of 0.30 m3 CH4/kg COD fed. The two-phase process was capable of high VS reduction, but material and energy balance showed that the single-phase process was superior in terms of volumetric methane production and energy yield by 33%. The lower energy yield of the two-phase system was due to the loss of energy during hydrolysis in the TPAR and the deficit in methane production in the TPMR attributed to COD loss due to biomass synthesis and adsorption of hard COD onto the flocs. These results including the complicated operational procedure of the two-phase process and the economic factors suggested that the single-phase process could be the preferred system for FVW.

  11. Anaerobic digestion for closing the loop of a biorefinery for organic farming: production of biogas and organic fertilizer from process residues

    DEFF Research Database (Denmark)

    Fernandez, Maria Santamaria; Karkov Ytting, Nanna; Lübeck, Mette

    2016-01-01

    were determined in batch and reactor experiments and mass balances of the nutrients were established based on analysis of N, P, K, and S from the different process stages (screw pressing, protein precipitation and AD process). The AD process was tested in lab-scale both as co-digestion of press cake......The availability of organic animal feed for monogastric animals and organic fertilizer is in many regions a limiting factor for the further spread of organic farming. The production of these two commodities based on regionally organically grown grass biomass is the main target of a green...... cake and brown juice at 20d hydraulic retention time (HRT) methane yields of 237 to 283 L-CH4/kg-VS were achieved while mesophilic treatment of brown juice in the high-rate reactor yielded on average 202 L-CH4/kg-VS at 3 days HRT. Nutrient analysis showed that most of the nutrients of the fresh crop...

  12. Methane production by anaerobic digestion of biomass. Final report of innovative research program subtask, December 1977--September 1978

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, V G

    1978-10-01

    It has long been known that methane is produced during the anaerobic digestion of agricultural wastes, but this potential source of fuel has not been greatly exploited in the United States. The chief reason is that anaerobic decomposition of lignocellulosic materials occurs very slowly, resulting in a need for long detention times and large digestion vessels, both of which markedly increase process costs. However, recent work at CSU has shown that pretreatment of manure fibers (an abundant agricultural waste) with saturated steam at 130 to 210/sup 0/C renders this material more susceptible to attack by microbial enzymes. The main objectives of this project were to identify the chemical events occurring during the steam treatment and to correlate these with the rate of methane generating during subsequent anaerobic digestion. The study was expected to lead to an optimal pretreatment strategy.

  13. 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.

  14. Anaerobic digestion of hemicellulose hydrolysate produced after hydrothermal pretreatment of sugarcane bagasse in UASB reactor.

    Science.gov (United States)

    Ribeiro, Fernanda Resende; Passos, Fabiana; Gurgel, Leandro Vinícius Alves; Baêta, Bruno Eduardo Lobo; de Aquino, Sérgio Francisco

    2017-04-15

    In the context of a sugarcane biorefinery, sugarcane bagasse produced may be pretreated generating a solid and liquid fraction. The solid fraction may be used for 2G bioethanol production, while the liquid fraction may be used to produce biogas through anaerobic digestion. The aim of this study consisted in evaluating the anaerobic digestion performance of hemicellulose hydrolysate produced after hydrothermal pretreatment of sugarcane bagasse. For this, hydrothermal pretreatment was assessed in a continuous upflow anaerobic sludge blanket (UASB) reactor operated at a hydraulic retention time (HRT) of 18.4h. Process performance was investigated by varying the dilution of sugarcane bagasse hydrolysate with a solution containing xylose and the inlet organic loading rate (OLR). Experimental data showed that an increase in the proportion of hydrolysate in the feed resulted in better process performance for steps using 50% and 100% of real substrate. The best performance condition was achieved when increasing the organic loading rate (OLR) from 1.2 to 2.4gCOD/L·d, with an organic matter removal of 85.7%. During this period, the methane yield estimated by the COD removal would be 270LCH4/kg COD. Nonetheless, when further increasing the OLR to 4.8gCOD/L·d, the COD removal decreased to 74%, together with an increase in effluent concentrations of VFA (0.80gCOD/L) and furans (115.3mg/L), which might have inhibited the process performance. On the whole, the results showed that anaerobic digestion of sugarcane bagasse hydrolysate was feasible and may improve the net energy generation in a bioethanol plant, while enabling utilization of the surplus sugarcane bagasse in a sustainable manner.

  15. Early-warning Indicators of Acidification in the Single-phase Anaerobic Digestion Process for Food Wastes%餐厨垃圾单相厌氧消化系统酸化预警指标

    Institute of Scientific and Technical Information of China (English)

    彭绪亚; 贾传兴; 潘坚; 刘国涛; 袁荣焕

    2011-01-01

    针对餐厨垃圾单相厌氧消化系统极易酸化、缺乏有效预警监控指标的技术瓶颈,在中温条件下利用自行设计的单相厌氧消化反应器,进行了实验室规模的启动、连续式单相厌氧消化系统运行试验,通过深入分析表征系统酸碱抵抗能力指标的变化规律,选取挥发性脂肪酸(VFA)、碳酸氢盐碱度与总碱度的比值(BA/TA)和挥发性脂肪酸总浓度与碳酸氢盐碱度的比值(VFA/BA)作为餐厨垃圾厌氧消化系统酸化抑制的指示性指标.当VFA/BA>0.8、BA/TA<0.4或VFA>3 000mg/L时,表明系统缓冲能力极小,应及时采取调控措施预防系统酸化;而当BA/TA≥0.8、VFA/BA<0.4时系统碱度较高,可以在较高负荷下运行以提高系统的产气效率.%The commonly used indicators are often too slow to reflect the operating status in time. Confronted with lacking reliable early-warning indices in the single-phase anaerobic digestion for kitchen waste which is easy to decay, lab-scale experiments of start-up and continuous operation process of anaerobic digestion for kitchen waste were carried out in the single-phase anaerobic reactor which is self-designed under mesophihc conditions. Those values which reflect the capacity of acidity-basicity resistance, including the ratio of bicarbonate alkalinity to total alkalinity (BA/TA), absolute testing value of volatile fatty acid (VFA) and the ratio of total concentration for volatile fatty acid to bicarbonate alkalinity (VFA/ BA), are determinated to be the early-warning indices for acidification and imbalance of single-phase anaerobic digestion for kitchen waste. It is considered that,when VFA/BA>0. 8,BA/TA 3000mg/L,buffering capacity of the system is very poor,and the system might be out of control. Therefore, an immediately steps must be taken. While,when BA/TA≥0.7~0. 8 and VFA/BA<0. 4,the alkalinity of system is relatively better and the process can be operated with higher organic volumetric

  16. Processing biogas plant digestates into value-added products - BIOVIRTA

    Energy Technology Data Exchange (ETDEWEB)

    Paavola, T. (MTT Agrifood Research Finland, Jokioinen (Finland)), e-mail: teija.paavola@mtt.fi; Torniainen, M. (Finnish Food Safety Authority, EVIRA, Helsinki (Finland)), e-mail: merja.torniainen@evira.fi; Kaparaju, P. (Jyvaeskylae Univ. (Finland)), e-mail: prasad.kaparaju@jyu.fi (and others)

    2011-11-15

    The objective of BIOVIRTA project is to develop technologies and practices with which digestates, originating from anaerobic digestion of different organic wastes and by-products can be refined to value-added and safe products for various end-uses. It is expected that the operational preconditions for biogas plants will be significantly enhanced when the end-products are proven safe and applicable. Selection of the raw materials for anaerobic co-digestion is the main operational strategy that could influence the nutrient content in the digestate. This has been clearly established in the laboratory and full-scale studies with various digestates originating from different raw materials. The nutrient content in the digestate also affects the opportunities to produce refined digestate products. In this project, the possibilities for several processing technologies, e.g. mechanical separation, stripping, and struvite production have been intensively evaluated for the production of different digestate products. Their mass balances have also been estimated. The feasibility for the use of the digestate products has been assessed based on their chemical and hygienic quality and for various end-uses, including as organic fertiliser and/or soil improver in crop production. The results of these field-experiments showed that the yield of barley fertilised with digestate products was comparable to inorganic fertilisers. (orig.)

  17. Impact of pretreatment on solid state anaerobic digestion of yard waste for biogas production.

    Science.gov (United States)

    Zhang, Zhikai; Li, Wangliang; Zhang, Guangyi; Xu, Guangwen

    2014-02-01

    Solid state anaerobic digestion, as a safe and environment-friendly technology to dispose municipal solid wastes, can produce methane and reduce the volume of wastes. In order to raise the digestion efficiency, this study investigated the pretreatment of yard waste by thermal or chemical method to break down the complex lignocellulosic structure. The composition and structure of pretreated yard waste were analyzed and characterized. The results showed that the pretreatment decreased the content of cellulose and hemicelluloses in yard waste and in turn improved the hydrolysis and methanogenic processes. The thermal pretreatment sample (P1) had the highest methane yield, by increasing 88% in comparison with digesting the raw material. The maximum biogas production reached 253 mL/g volatile solids (VS). The largest substrate mass reduction was obtained by the alkaline pretreatment (P5). The VS of the alkaline-treated sample decreased about 60% in comparison with the raw material.

  18. Feasibility assessment of anaerobic digestion of European water chestnuts (Trapa natans L. )

    Energy Technology Data Exchange (ETDEWEB)

    Besha, J.A.; Countryman, W.D.

    1980-07-01

    The project determined the technical and economic feasibility of anaerobic digestion of Trapa natans L. or European water chestnuts, to produce methane. Trapa natans is a nuisance aquatic plant presently found in the northeastern United States. The field data collection phase included color aerial photogrammetry and manual sampling. Yields of 9.08 kg per square meter of raw material with a corresponding dry weight of 1.53 kg/sq meter were determined. Bacterial digestion resulting in gas production of 69% methane and 31% carbon dioxide was shown in laboratory-scale digestion experiments. Mass spectrographic analysis indicated no contaminants in the gas stream. Conceptual technical design of a 400 kW methane-fueled electric generation facility indicated economic feasibility of this facility either as an independent or a hybrid process in conjunction with a small hydroelectric facility. Substantial economic and environmental benefits may accure from the control of Trapa natans by this means.

  19. Anaerobic digestion of autoclaved and untreated food waste

    Energy Technology Data Exchange (ETDEWEB)

    Tampio, Elina, E-mail: elina.tampio@mtt.fi [Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen (Finland); Ervasti, Satu; Paavola, Teija [Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen (Finland); Heaven, Sonia; Banks, Charles [University of Southampton, Faculty of Engineering and the Environment, Southampton SO17 1BJ (United Kingdom); Rintala, Jukka [Bioenergy and Environment, MTT Agrifood Research Finland, FI-31600 Jokioinen (Finland)

    2014-02-15

    Highlights: • Autoclaving decreased the formation of NH4-N and H{sub 2}S during food waste digestion. • Stable digestion was achieved with untreated and autoclaved FW at OLR 6 kg VS/m{sup 3}day. • Use of acclimated inoculum allowed very rapid increases in OLR. • Highest CH{sub 4} yields were observed at OLR 3 kg VS/m{sup 3}day with untreated FW. • Autoclaved FW produced highest CH{sub 4} yields during OLR 4 kgVS/m{sup 3}day. - Abstract: Anaerobic digestion of autoclaved (160 °C, 6.2 bar) and untreated source segregated food waste (FW) was compared over 473 days in semi-continuously fed mesophilic reactors with trace elements supplementation, at organic loading rates (OLRs) of 2, 3, 4 and 6 kg volatile solids (VS)/m{sup 3} d. Methane yields at all OLR were 5–10% higher for untreated FW (maximum 0.483 ± 0.013 m{sup 3} CH{sub 4}/kg VS at 3 kg VS/m{sup 3} d) than autoclaved FW (maximum 0.439 ± 0.020 m{sup 3} CH{sub 4}/kg VS at 4 kg VS/m{sup 3} d). The residual methane potential of both digestates at all OLRs was less than 0.110 m{sup 3} CH{sub 4}/kg VS, indicating efficient methanation in all cases. Use of acclimated inoculum allowed very rapid increases in OLR. Reactors fed on autoclaved FW showed lower ammonium and hydrogen sulphide concentrations, probably due to reduced protein hydrolysis as a result of formation of Maillard compounds. In the current study this reduced biodegradability appears to outweigh any benefit due to thermal hydrolysis of ligno-cellulosic components.

  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. Anaerobic co-digestion of animal waste: swine manure and tuna fish waste

    Energy Technology Data Exchange (ETDEWEB)

    Otero, L.; Alvarez, J. A.; Lema, J. M.

    2009-07-01

    Anaerobic digestion has become an established and proven technology for the treatment of solid wastes. Co-digestion offers several possible ecological, technology and economical advantages. Anaerobic co-digestion can increase CH{sub 4} production of manure diesters in a 50-200% according to the operation conditions and the co-substrates used. Last September 2007, PROBIOGAS project started up with the objective of improving the production and use of biogas from co-digestion of farming, agricultural and industrial waste. Our research group takes part in the study of co-digestion of swine manure firstly with tuna fish waste and secondly with glycerine (bio diesel production waste). (Author)

  2. The future of anaerobic digestion and biogas utilization

    DEFF Research Database (Denmark)

    Holm-Nielsen, J.B.; Al Seadi, T.; Oleskowicz-Popiel, Piotr

    2009-01-01

    , representing a considerable pollution threat for the environment in these areas. Avoiding over-fertilization is not only important for environmental protection reasons but also for economical reasons. Intensive animal production areas need therefore suitable manure management, aiming to export......One of the common tendencies of animal production activities in Europe and in developed countries in general is to intensify the animal production and to increase the size of the animal production units. High livestock density is always accompanied by production of a surplus of animal manure...... and to redistribute the excess of nutrients from manure and to optimize their recycling. Anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel – the biogas. The EU policies concerning renewable...

  3. Survival of human and plant pathogens during anaerobic mesophilic digestion of vegetable, fruit, and garden waste

    NARCIS (Netherlands)

    Termorshuizen, A.J.; Volker, D.; Blok, W.J.; Brummeler, ten E.; Hartog, B.J.; Janse, J.D.; Knol, W.; Wenneker, M.

    2003-01-01

    Five pathogens were added to vegetable, fruit and garden waste and their survival was studied during mesophilic (maximum temperature 40 degreesC) anaerobic digestion. Digestion during 6 weeks took. place with a 50/50% (v/v) ratio of digested and fresh, tem undigested material, respectively. Survival

  4. 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...

  5. Digestion of frozen/thawed food waste in the hybrid anaerobic solid-liquid system.

    Science.gov (United States)

    Stabnikova, O; Liu, X Y; Wang, J Y

    2008-01-01

    The hybrid anaerobic solid-liquid (HASL) system, which is a modified two-phase anaerobic digester, is to be used in an industrial scale operation to minimize disposal of food waste at incineration plants in Singapore. The aim of the present research was to evaluate freezing/thawing of food waste as a pre-treatment for its anaerobic digestion in the HASL system. The hydrolytic and fermentation processes in the acidogenic reactor were enhanced when food waste was frozen for 24h at -20 degrees C and then thawed for 12h at 25 degrees C (experiment) in comparison with fresh food waste (control). The highest dissolved COD concentrations in the leachate from the acidogenic reactors were 16.9 g/l on day 3 in the control and 18.9 g/l on day 1 in the experiment. The highest VFA concentrations in the leachate from the acidogenic reactors were 11.7 g/l on day 3 in the control and 17.0 g/l on day 1 in the experiment. The same volume of methane was produced during 12 days in the control and 7 days in the experiment. It gave the opportunity to diminish operational time of batch process by 42%. The effect of freezing/thawing of food waste as pre-treatment for its anaerobic digestion in the HASL system was comparable with that of thermal pre-treatment of food waste at 150 degrees C for 1h. However, estimation of energy required either to heat the suspended food waste to 150 degrees C or to freeze the same quantity of food waste to -20 degrees C showed that freezing pre-treatment consumes about 3 times less energy than thermal pre-treatment.

  6. Low temperature anaerobic digestion of mixtures of llama, cow and sheep manure for improved methane production

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Rene [IIDEPROQ, UMSA, Plaza del Obelisco 1175, La Paz (Bolivia)]|[Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund (Sweden); Liden, Gunnar [Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund (Sweden)

    2009-03-15

    Biogas production in anaerobic digestion in farm-scale units is typically performed under mesophilic conditions when used for producing domestic fuel and stabilizing animal waste for the use of digested manure as a fertilizer. Previous studies on the digestion of llama and cow manure have shown the feasibility of producing biogas under altiplano conditions (low pressure and low temperature) and of llama manure as a promising feedstock. The present study concerns the utilization of various mixtures of feedstocks from the Bolivian altiplano under low temperature conditions (18-25 C). Laboratory scale experiments were performed on the digestion of mixtures of llama, sheep and cow manure in a semi-continuous process using ten 2-L stainless steel digesters to determine the effects of organic loading rate (OLR) and the feed composition. The semi-continuous operation of mixture of llama-cow-sheep manure proved to be a reliable system, which could be operated with good stability. The results suggest that in a system digesting a mixture of llama-cow-sheep manure at low temperature (18-25 C) the maximum OLR value is between 4 and 6 kg VS m{sup 3} d{sup -1}. The methane yields obtained in the mixture experiments were in the range 0.07-0.14 m{sup 3} kg{sup -1} VS added, with a methane concentration in the gas of between 47 and 55%. (author)

  7. Long-chain fatty acids inhibition and adaptation process in anaerobic thermophilic digestion: Batch tests, microbial community structure and mathematical modelling

    DEFF Research Database (Denmark)

    Paltsi, Jordi; Illa, J.; Prenafeta-Boldu, F.X.

    2010-01-01

    Biomass samples taken during the continuous operation of thermophilic anaerobic digestors fed with manure and exposed to successive inhibitory pulses of long-chain fatty acids (LCFA) were characterized in terms of specific metabolic activities and 16S rDNA DGGE profiling of the microbial communit...

  8. On the effect of aqueous ammonia soaking pretreatment on batch and continuous anaerobic digestion of digested swine manure fibers

    DEFF Research Database (Denmark)

    Mirtsou Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis;

    2012-01-01

    to enhance their methane productivity in batch experiments. In the present study, continuous experiments at a mesophilic (38°C) CSTR-type anaerobic digester fed with swine manure first and a mixture of manure with AAS-treated digested fibers in the sequel, were performed. The methane yield of AAS...

  9. Anaerobic co-digestion of cattle manure with rice straw: economic & energy feasibility.

    Science.gov (United States)

    Silvestre, G; Gómez, M P; Pascual, A; Ruiz, B

    2013-01-01

    Rice straw (RS) is one of the most abundant wastes generated in Valencia (Spain). Traditional waste disposal methods are harmful to the environment. The straw burning emits large amounts of toxic air pollutants and the straw burying produces uncontrolled anaerobic fermentation in the soil. The aim of this research was to evaluate the feasibility of cow manure anaerobic co-digestion with RS in a semi-continuous plug flow pilot-scale reactor. Three different periods of co-digestion were carried out as the RS dose was increased. When the addition of RS was 1, 2 and 5% (on weight basis) the biogas productivity increased by 4, 28 and 54% respectively. Furthermore, economic and energy feasibility were analysed considering the logistics cost of the RS (baling, collection, crushing and transportation). Two different scenarios were analysed. In scenario 1, the anaerobic co-digestion process was considered that take place in a new biogas installation, and in scenario 2 the process was considered that take place in a biogas plant already in operation. In scenario 1, the cow manure co-digestion with 2% of RS in a biogas installation of 500 kW showed the best economic analysis (net present value of 13.23%). In scenario 2, the results showed that the maximum distance between the rice field and the biogas plant that produces a positive economic balance was less than 95 km (2% RS) and 74 km (5% RS). In the case of the addition of 1% RS the economic balance is negative. Energy balance is positive in the three mixtures analysed.

  10. Evaluation on direct interspecies electron transfer in anaerobic sludge digestion of microbial electrolysis cell.

    Science.gov (United States)

    Zhao, Zisheng; Zhang, Yaobin; Quan, Xie; Zhao, Huimin

    2016-01-01

    Increase of methanogenesis in methane-producing microbial electrolysis cells (MECs) is frequently believed as a result of cathodic reduction of CO2. Recent studies indicated that this electromethanogenesis only accounted for a little part of methane production during anaerobic sludge digestion. Instead, direct interspecies electron transfer (DIET) possibly plays an important role in methane production. In this study, anaerobic digestion of sludge were investigated in a single-chamber MEC reactor, a carbon-felt supplemented reactor and a common anaerobic reactor to evaluate the effects of DIET on the sludge digestion. The results showed that adding carbon felt into the reactor increased 12.9% of methane production and 17.2% of sludge reduction. Imposing a voltage on the carbon felt further improved the digestion. Current calculation showed that the cathodic reduction only contributed to 27.5% of increased methane production. Microbial analysis indicated that DIET played an important role in the anaerobic sludge digestion in the MEC.

  11. Syntrophic acetate oxidation in two-phase (acid-methane) anaerobic digesters.

    Science.gov (United States)

    Shimada, T; Morgenroth, E; Tandukar, M; Pavlostathis, S G; Smith, A; Raskin, L; Kilian, R E

    2011-01-01

    The microbial processes involved in two-phase anaerobic digestion were investigated by operating a laboratory-scale acid-phase (AP) reactor and analyzing two full-scale, two-phase anaerobic digesters operated under mesophilic (35 °C) conditions. The digesters received a blend of primary sludge and waste activated sludge (WAS). Methane levels of 20% in the laboratory-scale reactor indicated the presence of methanogenic activity in the AP. A phylogenetic analysis of an archaeal 16S rRNA gene clone library of one of the full-scale AP digesters showed that 82% and 5% of the clones were affiliated with the orders Methanobacteriales and Methanosarcinales, respectively. These results indicate that substantial levels of aceticlastic methanogens (order Methanosarcinales) were not maintained at the low solids retention times and acidic conditions (pH 5.2-5.5) of the AP, and that methanogenesis was carried out by hydrogen-utilizing methanogens of the order Methanobacteriales. Approximately 43, 31, and 9% of the archaeal clones from the methanogenic phase (MP) digester were affiliated with the orders Methanosarcinales, Methanomicrobiales, and Methanobacteriales, respectively. A phylogenetic analysis of a bacterial 16S rRNA gene clone library suggested the presence of acetate-oxidizing bacteria (close relatives of Thermacetogenium phaeum, 'Syntrophaceticus schinkii,' and Clostridium ultunense). The high abundance of hydrogen consuming methanogens and the presence of known acetate-oxidizing bacteria suggest that acetate utilization by acetate oxidizing bacteria in syntrophic interaction with hydrogen-utilizing methanogens was an important pathway in the second-stage of the two-phase digestion, which was operated at high ammonium-N concentrations (1.0 and 1.4 g/L). A modified version of the IWA Anaerobic Digestion Model No. 1 (ADM1) with extensions for syntrophic acetate oxidation and weak-acid inhibition adequately described the dynamic profiles of volatile acid production

  12. 动物消化机制用于木质纤维素的厌氧消化%Anaerobic Digestion of Lignocellulosic Biomass with Animal Digestion Mechanisms

    Institute of Scientific and Technical Information of China (English)

    吴昊; 张盼月; 郭建斌; 吴永杰

    2013-01-01

    木质纤维素是地球上最丰富的可再生资源,食草动物和食木昆虫能高效消化植物中的木质纤维素,模拟动物消化系统的厌氧消化反应器却达不到相应的效果.为了更好地理解动物消化机理,并应用于厌氧消化反应器的设计和运行,对食草动物和食木昆虫的消化机制以及木质纤维素厌氧消化工艺的发展趋势进行了综述.动物消化系统的高效消化是其消化道中各种酶的协同作用以及一系列物理和生物化学活动的结果.强大的预处理过程能有效支持微生物发酵系统,如反刍动物的反刍、食木昆虫分泌的纤维素酶的催化及食木昆虫其消化道中的碱处理等;沿消化道形成的氧浓度梯度可能刺激一些微生物的水解活性;固体停留时间、消化物流动和终产物排除的有序安排,均能促进动物高效消化木质纤维素.源于瘤胃的厌氧消化工艺接种了瘤胃中的微生物降解木质纤维素,但其厌氧反应器内的环境条件对发酵的限制远远大于瘤胃发酵或后肠发酵的情况.因此,模拟动物消化机制可以更有效促进厌氧消化工艺降解木质纤维素类固体有机物废物.%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

  13. Interests of membrane processes in liquid digestate post-treatment and by-product valorisation

    OpenAIRE

    Carretier, Séverine

    2014-01-01

    Intense spreading of livestock wastes are recognized to be detrimental to the environment due to their content of organic matter and mineral fraction. Then, it would appear to be necessary to promote greens treatments processes. In fact, anaerobic digestion allows the production of biogas (extremely useful source of renewable energy), whilst digestate should be a highly valuable biofertilizer This work enters in this approach by proposing to complete anaerobic digestion steps by the use of pe...

  14. Nitrogen and phosphorus recovery from anaerobic co-digestion residues of poultry manure and maize silage via struvite precipitation.

    Science.gov (United States)

    Yilmazel, Y Dilsad; Demirer, Goksel N

    2013-08-01

    Anaerobic digestion is commonly used for the stabilization of agricultural and animal wastes. However, owing to the stringent environmental criteria, anaerobic digester effluents need to be further treated to reduce nutrient loads to the receiving water bodies. Struvite precipitation is one of the promising techniques applied for this purpose. Yet, in the majority of cases, struvite precipitation is only applied to the liquid phase of anaerobic digester effluents. This study investigated the recovery of nutrients from both the liquid and the solid phases of the phase-separated effluent of a full-scale biogas plant co-digesting poultry manure and maize silage. Struvite precipitation in the liquid phase led to 72.1% and 95.1% average removal efficiencies of ammonium-nitrogen (NH4-N) and orthophosphate respectively. Changing the external phosphorus source did not make any statistically significant difference in nutrient removal. An acidic phosphorus-dissolution process was applied to the solid phase sample to obtain a phosphorus-enriched solution. More than 90.0% of both NH4-N and PO4-P were recovered from the phosphorus-enriched solution with the amendments of magnesium and phosphorus. In the experiments performed without any addition of external magnesium- and phosphorus-containing chemicals, almost complete (99.6%) PO4-P recovery and partial (14.6%) NH4-N recovery were obtained. The results of this study could contribute to the understanding of nutrient recovery from anaerobic digestion residues of manure and agricultural wastes by struvite precipitation.

  15. Anaerobic digestion of autoclaved and untreated food waste.

    Science.gov (United States)

    Tampio, Elina; Ervasti, Satu; Paavola, Teija; Heaven, Sonia; Banks, Charles; Rintala, Jukka

    2014-02-01

    Anaerobic digestion of autoclaved (160°C, 6.2 bar) and untreated source segregated food waste (FW) was compared over 473 days in semi-continuously fed mesophilic reactors with trace elements supplementation, at organic loading rates (OLRs) of 2, 3, 4 and 6 kg volatile solids(VS)/m(3)d. Methane yields at all OLR were 5-10% higher for untreated FW (maximum 0.483±0.013 m(3) CH4/kg VS at 3 kg VS/m(3) d) than autoclaved FW (maximum 0.439±0.020 m(3) CH4/kg VS at 4 kg VS/m(3) d). The residual methane potential of both digestates at all OLRs was less than 0.110 m(3) CH4/kg VS, indicating efficient methanation in all cases. Use of acclimated inoculum allowed very rapid increases in OLR. Reactors fed on autoclaved FW showed lower ammonium and hydrogen sulphide concentrations, probably due to reduced protein hydrolysis as a result of formation of Maillard compounds. In the current study this reduced biodegradability appears to outweigh any benefit due to thermal hydrolysis of ligno-cellulosic components.

  16. Application of urea dosing for alkalinity supply during anaerobic digestion of vinasse.

    Science.gov (United States)

    Boncz, M A; Formagini, E L; Santos, L da S; Marques, R D; Paulo, P L

    2012-01-01

    Pushed by demand for renewable energy, the ethanol industry in Brazil is expanding. However, production of 1 m(3) of ethanol generates around 13 m(3) of liquid residues (vinasse), so this expansion results in an increasing need for a more adequate destination of these residues. Nowadays the vinasse is dispersed on the sugar cane fields in the practice of fertirrigation, but anaerobic digestion of this residue may be a better solution, additionally offering an alternative source of energy, able to complement hydroelectric power supply in the dry season. However, when trying to digest vinasse at reduced hydraulic retention times, complications arise from its strong tendency toward acidification, upsetting the fragile balance of transformations normally occurring under anaerobic conditions. For successful operation of an anaerobic treatment process with acceptable hydraulic residence times, increasing alkalinity levels inside the reactor is neces-sary. In the present work we show that pH regulation by means of urea dosing, in spite of the risk posed by ammonia toxicity towards methanogenic biomass, can be a viable alternative to avoid vinasse acidification. The ammonia formed in urea conversion remains in solution, rather than escaping to the biogas, and so its use as fertiliser can offset its cost of application in the process.

  17. Anaerobic co-digestion of kitchen waste and pig manure with different mixing ratios.

    Science.gov (United States)

    Tian, Hailin; Duan, Na; Lin, Cong; Li, Xue; Zhong, Mingzhu

    2015-07-01

    Anaerobic co-digestion of kitchen waste (KW) and pig manure (PM) with seven different PM to KW total solids (TS) ratios of 1:0, 5:1, 3:1, 1:1, 1:3, 1:5 and 0:1 was conducted at mesophilic temperature (35 ± 1 °C) to investigate the feasibility and process performance. The co-digestion of PM and KW was found to be an available way to enhance methane production compared with solo-digestion of PM or KW. The ratio of PM to KW of 1:1 got the highest biodegradability (BDA) of 85.03% and a methane yield of 409.5 mL/gVS. For the co-digestion of KW and PM, there was no obvious inhibition of ammonia nitrogen because it was in an acceptable range from 1380 mg/L to 2020 mg/L in the whole process. However, severe methane inhibition and long lag phase due to the accumulation of volatile fatty acids (VFAs) was observed while the KW content was over 50%, and in the lag phase, propionic acid and butyric acid made up the major constituents of the total VFAs. The technical digestion time (T80: the time it takes to produce 80% of the digester's maximum gas production) of the above 7 ratios was 15, 21, 22, 27, 49, 62 and 61 days, respectively. In this study, a mixing ratio of 1:1 for PM and KW was found to maximize BDA and methane yield, provided a short digestion time and stable digestion performance and was therefore recommended for further study and engineering application.

  18. Assessing solid digestate from anaerobic digestion as feedstock for ethanol production.

    Science.gov (United States)

    Teater, Charles; Yue, Zhengbo; MacLellan, James; Liu, Yan; Liao, Wei

    2011-01-01

    Ethanol production using solid digestate (AD fiber) from a completely stirred tank reactor (CSTR) anaerobic digester was assessed comparing to an energy crop of switchgrass, and an agricultural residue of corn stover. A complete random design was fulfilled to optimize the reaction conditions of dilute alkali pretreatment. The most effective dilute alkali pretreatment conditions for raw CSTR AD fiber were 2% sodium hydroxide, 130 °C, and 3 h. Under these pretreatment conditions, the cellulose concentration of the AD fiber was increased from 34% to 48%. Enzymatic hydrolysis of 10% (dry basis) pretreated AD fiber produced 49.8 g/L glucose, while utilizing 62.6% of the raw cellulose in the AD fiber. The ethanol fermentation on the hydrolysate had an 80.3% ethanol yield. The cellulose utilization efficiencies determined that the CSTR AD fiber was a suitable biorefining feedstock compared to switchgrass and corn stover.

  19. Anaerobic Digestion and Combined Heat and Power Study

    Energy Technology Data Exchange (ETDEWEB)

    Frank J. Hartz

    2011-12-30

    One of the underlying objectives of this study is to recover the untapped energy in wastewater biomass. Some national statistics worth considering include: (1) 5% of the electrical energy demand in the US is used to treat municipal wastewater; (2) This carbon rich wastewater is an untapped energy resource; (3) Only 10% of wastewater treatment plants (>5mgd) recover energy; (4) Wastewater treatment plants have the potential to produce > 575 MW of energy nationwide; and (5) Wastewater treatment plants have the potential to capture an additional 175 MW of energy from waste Fats, Oils and Grease. The WSSC conducted this study to determine the feasibility of utilizing anaerobic digestion and combined heat and power (AD/CHP) and/or biosolids gasification and drying facilities to produce and utilize renewable digester biogas. Digester gas is considered a renewable energy source and can be used in place of fossil fuels to reduce greenhouse gas emissions. The project focus includes: (1) Converting wastewater Biomass to Electricity; (2) Using innovative technologies to Maximize Energy Recovery; and (3) Enhancing the Environment by reducing nutrient load to waterways (Chesapeake Bay), Sanitary Sewer Overflows (by reducing FOG in sewers) and Greenhouse Gas Emissions. The study consisted of these four tasks: (1) Technology screening and alternative shortlisting, answering the question 'what are the most viable and cost effective technical approaches by which to recover and reuse energy from biosolids while reducing disposal volume?'; (2) Energy recovery and disposal reduction potential verification, answering the question 'how much energy can be recovered from biosolids?'; (3) Economic environmental and community benefit analysis, answering the question 'what are the potential economic, environmental and community benefits/impacts of each approach?'; and (4) Recommend the best plan and develop a concept design.

  20. 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.

  1. Microalgae to biofuels: life cycle impacts of methane production of anaerobically digested lipid extracted algae.

    Science.gov (United States)

    Quinn, Jason C; Hanif, Asma; Sharvelle, Sybil; Bradley, Thomas H

    2014-11-01

    This study presents experimental measurements of the biochemical methane production for whole and lipid extracted Nannochloropsis salina. Results show whole microalgae produced 430 cm(3)-CH4 g-volatile solids(-1) (g-VS) (σ=60), 3 times more methane than was produced by the LEA, 140 cm(3)-CH4 g-VS(-1) (σ=30). Results illustrate current anaerobic modeling efforts in microalgae to biofuel assessments are not reflecting the impact of lipid removal. On a systems level, the overestimation of methane production is shown to positively skew the environmental impact of the microalgae to biofuels process. Discussion focuses on a comparison results to those of previous anaerobic digestion studies and quantifies the corresponding change in greenhouse gas emissions of the microalgae to biofuels process based on results from this study.

  2. Carbon dynamics and retention in soil after anaerobic digestion of dairy cattle feed and faeces

    DEFF Research Database (Denmark)

    Thomsen, Ingrid Kaag; Olesen, Jørgen E; Møller, Henrik Bjarne

    2013-01-01

    Animal manure and plant biomass are increasingly used for methane production. While minerals may be conserved during gas generation, the composition of the biogenic material is changed and less carbon (C) is returned to the soil in the digested residue. We evaluated the fate of C in ruminant feed....... When C lost during the pre-treatments was included, the long-term C retention in soil accounted for 12–14% of the C initially present in the feed. We conclude that soil microbial activity is reduced when residues are anaerobically digested for biogas before being applied to soil. However, the retention...... treated differently before added to soil: no treatment (feed), anaerobic digestion (digested feed), consumed by cattle (faeces), consumed by cattle and anaerobic digestion (digested faeces). The materials were incubated for 245 days at 20 °C. The net CO2 release was determined and fitted to a kinetic C...

  3. 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

  4. Hydrolysis and thermophilic anaerobic digestion of sewage sludge and organic fraction of municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Del Borghi, A.; Converti, A.; Palazzi, E.; Del Borghi, M. [Institute of Chemical and Process Engineering ``G.B. Bonino``, Genoa University, Via Opera Pia 15, 16145 Genoa (Italy)

    1999-06-01

    An attempt is presented and discussed to adapt a well-known process successfully employed in the U.S.A. for the simultaneous treatment of the organic fraction of municipal solid waste (MSWOF) and sewage sludge to the particular situation of water works in Italy. It consists of preliminary domestic grinding of MSWOF, its discharge into the sewer, screening, and final digestion of the resulting residue together with sewage sludge. In order to avoid extension work of the present activated sludge sections necessary to face the organic load increase, a fine screening is necessary, while the efficiency of anaerobic digestion can be improved by shifting the system from mesophilic (37 C) to thermophilic (55 C) conditions. The effects of thermal, chemical, and biological pretreatments of both MSWOF and sewage sludge on methane, carbon dioxide, and biogas productions are investigated either separately or jointly. During these pretreatments, volatile suspended solid (VSS) concentration remarkably decreased while soluble chemical oxygen demand (COD) increased as the result of the progressive hydrolysis of the polymeric materials present in the feed. Finally, the kinetic parameters of the hydrolysis of these materials are estimated and compared in order to provide useful information on the factors limiting the anaerobic digestion as well as to suggest the best way to carry out the process on a large scale. (orig.) With 8 figs., 7 tabs., 20 refs.

  5. Analysis of biogas production through anaerobics digestion using cow dung and various co-substrates

    Directory of Open Access Journals (Sweden)

    Dhanapal Thamilselvan

    2016-01-01

    Full Text Available Biodegradable waste is a sustainable energy resource. In coming years biogas technology can be very useful worldwide, since biogas can be obtained from biodegradable waste material. This technology is based on waste reduction and also is helpful in the clean-up process of India. In this experiment, we have made single-phase biogas set-ups by using two-liter bottles. The fermentation time of the anaerobic digestion for the efficient use of gas as a fuel is about sixteen days. In our biogas digester set-ups for waste decomposion anaerobic co-digestion process is utilized. The primary feed stock is cow dung, whereas the grass, fruit, and vegetable waste are used as co-subtracts. The pH value was maintained at the range level of 6.5 to 6.9. The output biogas yield was 1.59 ml, 1.28 ml, 1.03 ml, and 0.95 ml, within an approximate period of sixteen days. Biogas obtained from cow dung and grass waste is almost identical as biogas obtained from the experimental set-up 1 (pure cow dung. Main performance characteristics of biogas formation were presented in this paper. In order to analyze a daily biogas formation, the pH value, temperature, and hydraulic retention time were changed in this experiment.

  6. A self-sustaining advanced lignocellulosic biofuel production by integration of anaerobic digestion and aerobic fungal fermentation.

    Science.gov (United States)

    Zhong, Yuan; Ruan, Zhenhua; Zhong, Yingkui; Archer, Steven; Liu, Yan; Liao, Wei

    2015-03-01

    High energy demand hinders the development and application of aerobic microbial biofuel production from lignocellulosic materials. In order to address this issue, this study focused on developing an integrated system including anaerobic digestion and aerobic fungal fermentation to convert corn stover, animal manure and food wastes into microbial lipids for biodiesel production. Dairy manure and food waste were first anaerobically digested to produce energy and solid digestate (AD fiber). AD fiber and corn stover were then processed by a combined alkali and acid hydrolysis, followed by fungal lipid accumulation. The integrated process can generate 1L biodiesel and 1.9 kg methane from 12.8 kg dry dairy manure, 3.1 kg dry food wastes and 12.2 kg dry corn stover with a positive net energy of 57 MJ, which concludes a self-sustaining lignocellulosic biodiesel process and provides a new route to co-utilize corn stover and organic wastes for advanced biofuel production.

  7. Co-digestion of tobacco waste with different agricultural biomass feedstocks and the inhibition of tobacco viruses by anaerobic digestion.

    Science.gov (United States)

    Liu, Yi; Dong, Jianxin; Liu, Gangjin; Yang, Hongnan; Liu, Wei; Wang, Lan; Kong, Chuixue; Zheng, Dan; Yang, Jinguang; Deng, Liangwei; Wang, Shusheng

    2015-01-01

    Tobacco is widely planted across the world especially in China, which means that a large amount of tobacco waste needs to be treated. This study investigated the biogas fermentation of tobacco stalks co-digested with different biomass feedstocks and the inactivation of Tobacco mosaic virus (TMV), Cucumber mosaic virus (CMV) by anaerobic digestion. Results showed that the maximum methane yield of tobacco stalks at 35 °C was 0.163 m(3) CH4 ⋅ kg VS(-1), which was from the co-digestion of tobacco stalks, wheat stalks and pig manure. The largest VS removal rate of tobacco stalks was 59.10%. Proven by indicator paper stripe, half-leaf lesion and RT-PCR, CMV could be inactivated by mesophilic and thermophilic anaerobic digestion, whereas TMV could be only inactivated by thermophilic anaerobic digestion over 20 days. These results suggested that using tobacco stalks as feedstock for anaerobic digestion and applying the digested residue and slurry to Solanaceae crop land are feasible.

  8. The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge

    Directory of Open Access Journals (Sweden)

    Tatiana Prado

    2013-02-01

    Full Text Available The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV, rotavirus species A (RVA, norovirus genogroup II (NoV GII and the hepatitis A virus (HAV from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%, RVA, NoV GII (45% and HAV (18%, indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management.

  9. Evaluation of single vs. staged mesophilic anaerobic digestion of kitchen waste with and without microwave pretreatment.

    Science.gov (United States)

    Shahriari, Haleh; Warith, Mostafa; Hamoda, Mohamed; Kennedy, Kevin

    2013-08-15

    Effects of single and dual stage (acidogenic-methanogenic) mesophilic anaerobic digestion (AD) of kitchen waste (KW) was evaluated at hydraulic retention times (HRTs) of 20, 15, 12 and 9 d with and without thermal microwave (MW) pretreatment (145 °C). Anaerobic acidification in terms of acid accumulation was superior compared to microaerophilic acidification. Maximum anaerobic acidification of KW was determined to occur with an HRT of 2 d which was then selected for the acidification stage. The dual stage AD system fed with untreated KW produced the maximum biogas and volatile solids (VS) stabilization efficiencies at the shortest HRT of 9 d. Conversely, for free liquid resulting from MW pretreatment of KW the two stage reactor at 20 d HRT produced three fold more methane compared with the untreated free liquid control. However, MW pretreatment and AD of the free liquid fraction only, was not a sustainable treatment option. For KW, staging of the AD process had a greater positive impact on waste stabilization and methane yield compared to single stage reactors or MW pretreatment. KW can be characterized as being a readily biodegradable solid waste; concomitantly it is recommended that digester staging without MW pretreatment be employed to maximize methane yield and production.

  10. The efficiency of concentration methods used to detect enteric viruses in anaerobically digested sludge

    Science.gov (United States)

    Prado, Tatiana; Guilayn, Wilma de Carvalho Pereira Bonet; Gaspar, Ana Maria Coimbra; Miagostovich, Marize Pereira

    2013-01-01

    The presence of enteric viruses in biosolids can be underestimated due to the inefficient methods (mainly molecular methods) used to recover the viruses from these matrices. Therefore, the goal of this study was to evaluate the different methods used to recover adenoviruses (AdV), rotavirus species A (RVA), norovirus genogroup II (NoV GII) and the hepatitis A virus (HAV) from biosolid samples at a large urban wastewater treatment plant in Brazil after they had been treated by mesophilic anaerobic digestion. Quantitative polymerase chain reaction (PCR) was used for spiking experiments to compare the detection limits of feasible methods, such as beef extract elution and ultracentrifugation. Tests were performed to detect the inhibition levels and the bacteriophage PP7 was used as an internal control. The results showed that the inhibitors affected the efficiency of the PCR reaction and that beef extract elution is a suitable method for detecting enteric viruses, mainly AdV from biosolid samples. All of the viral groups were detected in the biosolid samples: AdV (90%), RVA, NoV GII (45%) and HAV (18%), indicating the viruses' resistance to the anaerobic treatment process. This is the first study in Brazil to detect the presence of RVA, AdV, NoV GII and HAV in anaerobically digested sludge, highlighting the importance of adequate waste management. PMID:23440119

  11. Anaerobic digestion and co-digestion of slaughterhouse waste (SHW): influence of heat and pressure pre-treatment in biogas yield.

    Science.gov (United States)

    Cuetos, M J; Gómez, X; Otero, M; Morán, A

    2010-10-01

    Mesophilic anaerobic digestion (34+/-1 degrees C) of pre-treated (for 20 min at 133 degrees C, >3 bar) slaughterhouse waste and its co-digestion with the organic fraction of municipal solid waste (OFMSW) have been assessed. Semi-continuously-fed digesters worked with a hydraulic retention time (HRT) of 36 d and organic loading rates (OLR) of 1.2 and 2.6 kg VS(feed)/m(3)d for digestion and co-digestion, respectively, with a previous acclimatization period in all cases. It was not possible to carry out an efficient treatment of hygienized waste, even less so when OFMSW was added as co-substrate. These digesters presented volatile fatty acids (VFA), long chain fatty acids (LCFA) and fats accumulation, leading to instability and inhibition of the degradation process. The aim of applying a heat and pressure pre-treatment to promote splitting of complex lipids and nitrogen-rich waste into simpler and more biodegradable constituents and to enhance biogas production was not successful. These results indicate that the temperature and the high pressure of the pre-treatment applied favoured the formation of compounds that are refractory to anaerobic digestion. The pre-treated slaughterhouse wastes and the final products of these systems were analyzed by FTIR and TGA. These tools verified the existence of complex nitrogen-containing polymers in the final effluents, confirming the formation of refractory compounds during pre-treatment.

  12. Comparison of solid-state anaerobic digestion and composting of yard trimmings with effluent from liquid anaerobic digestion.

    Science.gov (United States)

    Lin, Long; Yang, Liangcheng; Xu, Fuqing; Michel, Frederick C; Li, Yebo

    2014-10-01

    Solid-state anaerobic digestion (SS-AD) and composting of yard trimmings with effluent from liquid AD were compared under thermophilic condition. Total solids (TS) contents of 22%, 25%, and 30% were studied for SS-AD, and 35%, 45%, and 55% for composting. Feedstock/effluent (F/E) ratios of 2, 3, 4, 5, and 6 were tested. In composting, the greatest carbon loss was obtained at 35% TS, which was 2-3 times of that at 55% TS and was up to 50% higher than that in SS-AD. In SS-AD, over half of the degraded carbon was converted to methane with the greatest methane yield of 121 L/kg VS(feedstock). Methane production from SS-AD was low at F/E ratios of 2 and 3, likely due to the inhibitory effect of high concentrations of ammonia nitrogen (up to 5.6g/kg). The N-P-K values were similar for SS-AD digestate and compost with different dominant nitrogen forms.

  13. Microbial community dynamics of a continuous mesophilic anaerobic biogas digester fed with sugar beet silage

    Energy Technology Data Exchange (ETDEWEB)

    Demirel, B.; Neumann, L.; Scherer, P. [Hochschule fuer Angewandte Wissenschaften, Fakultaet Life Sciences, Lifetec Process Engineering, Hamburg (Germany)

    2008-08-15

    The aim of the study was to investigate the long-term fermentation of an extremely sour substrate without any addition of manure. In the future, the limitation of manure and therefore the anaerobic digestion of silage with a very low buffering capacity will be an increasing general bottleneck for energy production from renewable biomass. During the mesophilic anaerobic digestion of sugar beet silage (without top and leaves) as the sole substrate (without any addition of manure), which had an extreme low pH of around 3.3, the highest specific gas production rate (spec. GPR) of 0.72 L/g volatile solids (VS) d was achieved at a hydraulic retention time (HRT) of 25 days compared to an organic loading rate (OLR) of 3.97 g VS/L d at a pH of around 6.80. The methane (CH{sub 4}) content of the digester ranged between 58 and 67 %, with an average of 63 %. The use of a new charge of substrate (a new harvest of the same substrate) with higher phosphate content improved the performance of the biogas digester significantly. The change of the substrate charge also seemed to affect the methanogenic population dynamics positively, thus improving the reactor performance. Using a new substrate charge, a further decrease in the HRT from 25 to 15 days did not influence the digester performance and did not seem to affect the structure of the methanogenic population significantly. However, a decrease in the HRT affected the size of the methanogenic population adversely. The lower spec. GPR of 0.54 L/g VS d attained on day 15 of the HRT could be attributed to a lower size of methanogenic population present in the anaerobic digester during this stage of the process. Furthermore, since sugar beet silage is a relatively poor substrate, in terms of the buffering capacity and the availability of nutrients, an external supply of buffering agents and nutrients is a prerequisite for a safe and stable digester operation. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  14. Use of an anaerobic sequencing batch reactor for parameter estimation in modelling of anaerobic digestion.

    Science.gov (United States)

    Batstone, D J; Torrijos, M; Ruiz, C; Schmidt, J E

    2004-01-01

    The model structure in anaerobic digestion has been clarified following publication of the IWA Anaerobic Digestion Model No. 1 (ADM1). However, parameter values are not well known, and uncertainty and variability in the parameter values given is almost unknown. Additionally, platforms for identification of parameters, namely continuous-flow laboratory digesters, and batch tests suffer from disadvantages such as long run times, and difficulty in defining initial conditions, respectively. Anaerobic sequencing batch reactors (ASBRs) are sequenced into fill-react-settle-decant phases, and offer promising possibilities for estimation of parameters, as they are by nature, dynamic in behaviour, and allow repeatable behaviour to establish initial conditions, and evaluate parameters. In this study, we estimated parameters describing winery wastewater (most COD as ethanol) degradation using data from sequencing operation, and validated these parameters using unsequenced pulses of ethanol and acetate. The model used was the ADM1, with an extension for ethanol degradation. Parameter confidence spaces were found by non-linear, correlated analysis of the two main Monod parameters; maximum uptake rate (k(m)), and half saturation concentration (K(S)). These parameters could be estimated together using only the measured acetate concentration (20 points per cycle). From interpolating the single cycle acetate data to multiple cycles, we estimate that a practical "optimal" identifiability could be achieved after two cycles for the acetate parameters, and three cycles for the ethanol parameters. The parameters found performed well in the short term, and represented the pulses of acetate and ethanol (within 4 days of the winery-fed cycles) very well. The main discrepancy was poor prediction of pH dynamics, which could be due to an unidentified buffer with an overall influence the same as a weak base (possibly CaCO3). Based on this work, ASBR systems are effective for parameter

  15. Recovery of energy from Taro (Colocasia esculenta) with solid-feed anaerobic digesters (SOFADs).

    Science.gov (United States)

    Bindu, T; Ramasamy, E V

    2008-01-01

    We present studies on solid-feed anaerobic digesters (SOFADs) in which chopped Colocasia esculenta was fed without any other pretreatment, in an attempt to develop an efficient means of utilizing the semi-aquatic weed that is otherwise an environmental nuisance. Two types of SOFADs were studied. The first type had a single vessel with two compartments. The lower portion of the digester, 25% of the total volume, was separated from the upper by a perforated PVC disk. The weed was charged from the top and inoculated with anaerobically digested cow dung-water slurry. The fermentation of the weed in the digester led to the formation of volatile fatty acids (VFAs) plus some biogas. The bioleachate, rich in the VFAs, passed through the perforated PVC disk and was collected in the lower compartment of the digester. The other type of digesters, referred to as anaerobic multi-phase high-solids digesters (AMHDs), had the same type of compartmentalized digester unit as the first type and an additional methaniser unit. Up-flow anaerobic filters (UAFs) were used as methaniser units, which converted the bioleachate into combustible biogas consisting of approximately 60% methane. All SOFADs developed a consistent performance in terms of biogas yield within 20 weeks from the start. Among the two types of digesters studied, the AMHDs were found to perform better with a twofold increase in biogas yield compared to the first type of digesters.

  16. Microbial anaerobic digestion (bio-digesters) as an approach to the decontamination of animal wastes in pollution control and the generation of renewable energy.

    Science.gov (United States)

    Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael

    2013-09-17

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester) via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas) and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications.

  17. Microbial Anaerobic Digestion (Bio-Digesters as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    Directory of Open Access Journals (Sweden)

    Golden Makaka

    2013-09-01

    Full Text Available With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications.

  18. Significance of vivianite precipitation on the mobility of iron in anaerobically digested sludge

    Directory of Open Access Journals (Sweden)

    Jimmy Roussel

    2016-09-01

    Full Text Available Anaerobic digestion requires a balanced availability of micro-nutrients with ideal growth conditions to reach optimal organic degradation and biogas production. Iron is the most abundant of the essential metals in an anaerobic digester and its mobility has a strong impact on microorganisms through its own bioavailability, but also through its influence on the bioavailability of other metals. Most previous research on iron mobility in anaerobic digestion has focused on sulfide as the controlling anion because digesters traditionally are sulfide rich and phosphate poor. However, chemical phosphorus removal (CPR at wastewater treatment works (WWTW can elevate phosphate concentrations in the digester 10-fold or more. The goal of this research was hence to examine the accepted wisdom of iron-sulfide dominance prevailing in all anaerobic digesters and by evaluating the potential for iron phosphate formation in municipal digesters treating CPR sludge. To fulfil this aim, iron compounds were identified experimentally from full-scale digesters at WWTW with CPR and the most likely iron species identified through modelling according to their thermodynamic probability of formation under the specific environmental conditions experienced in each anaerobic digester. Experimental and modelling data were then combined to identify the main chemical reactions controlling iron mobility in those anaerobic digesters.Results show that speciation of iron in the sampled anaerobic digesters was controlled by the solid phase through a primary reaction (sulfide precipitation to form pyrite and ferrous sulfide and secondary reaction (phosphate precipitation to form vivianite. However, iron-sulfide precipitates represented only 10-30% of the total iron in the sampled digesters, while iron-phosphate precipitates represented more than 70%. The significance of the high quantity of vivianite in these digesters is that phosphate-rich anaerobic digesters will be more iron

  19. 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.

  20. Impact of Organic Loading Rate on Psychrophilic Anaerobic Digestion of Solid Dairy Manure

    Directory of Open Access Journals (Sweden)

    Noori M. Cata Saady

    2015-03-01

    Full Text Available Increasing the feed total solids to anaerobic digester improves the process economics and decreases the volume of liquid effluent from current wet anaerobic digestion. The objective of this study was to develop a novel psychrophilic (20 °C anaerobic digestion technology of undiluted cow feces (total solids of 11%–16%. Two sets of duplicate laboratory-scale sequence batch bioreactors have been operated at organic loading rates (OLR of 6.0 to 8.0 g total chemical oxygen demand (TCOD kg−1 inoculum day−1 (d−1 during 210 days. The results demonstrated that the process is feasible at treatment cycle length (TCL of 21 days; however, the quality of cow feces rather than the OLR had a direct influence on the specific methane yield (SMY. The SMY ranged between 124.5 ± 1.4 and 227.9 ± 4.8 normalized liter (NL CH4 kg−1 volatile solids (VS fed d−1. Substrate-to-inoculum mass ratio (SIR was 0.63 ± 0.05, 0.90 ± 0.09, and 1.06 ± 0.07 at OLR of 6.0, 7.0, and 8.0 g TCOD kg−1 inoculum d−1, respectively. No volatile fatty acids (VFAs accumulation has been observed which indicated that hydrolysis was the rate limiting step and VFAs have been consumed immediately. Bioreactors performance consistency in terms of the level of SMYs, VFAs concentrations at end of the TCL, pH stability and volatile solids reduction indicates a stable and reproducible process during the entire operation.

  1. 废弃食用油脂两相厌氧发酵酸化条件优化%Process optimization of wasted edible oil hydrolytic acidification in two-phase anaerobic digestion

    Institute of Scientific and Technical Information of China (English)

    贺静; 邓雅月; 李凛; 李政伟; 尹小波; 邓宇

    2015-01-01

    It was reported that in China the annual consumption of edible oil was 21×106 tons which consequently produced waste oil of about 6×106 tons. The waste oil can be recycled to produce biodiesel, bulk chemicals, surfactant, fine chemicals and biogas. The recycling and bioconversion of waste edible oil into biogas will be beneficial to energy crisis and environmental pollution, and promote sustainable economic development. Because of the suppression of long chain fatty acid that is one of intermediate metabolites, waste edible oil that is directly used in anaerobic fermentation often causes digestion inhibition or system crash. The two-phase anaerobic digestion process can avoid the accumulation of long chain fatty acid and volatile acid in the methanogenesis process. Waste edible oil hydrolysis and long chain fatty acid degradation are critical steps in anaerobic digestion of waste edible oil. Improving the production rate of volatile fatty acid (VFA) in hydrolysis acidification phase will raise the subsequent methanogenesis reaction. The response surface methodology (RSM) can obtain the best combination of the factors in a given area and the optimal value of response values, which has been widely used in the optimization of culture conditions and technology conditions in the areas of food processing, water treatment and so on. Therefore, the RSM was used to optimize waste oil biological hydrolysis to produce volatile acid (including acetic acid, propionic acid and butyric acid). By adopting the method of central composite design (CCD) line design of experiment, using the soft Design Expert to analyze the experiment result, we established the quadratic polynomial in which volatile acid concentration was taken as the response value. The effects of initial pH value, raw material load, reaction time and inoculation rate on volatile acid concentration were investigated. The mathematical model and optimized parameters of process were also acquired. The results showed

  2. Anaerobic co-digestion of sewage sludge. Application to the macroalgae from the Venice lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, F. [University of L`Aquila, Department of Chemistry, Chemical Engineering and Materials, Abruzzo (Italy); Pavan, P. [Environmental Sciences, University of Venice, Venice (Italy); Mata-Alvarez, J. [Department of Chemical Engineering, University of Barcelona, Barcelona (Spain)

    1996-07-05

    Possibilities of co-digestion of sewage sludge (SS) with other organic wastes are examined in this paper. Anaerobic co-digestion of macroalgae of the Venice lagoon (A) with SS, in wastewater treatment plants is studied in detail. This approach can contribute to the solution of the final disposal of the 50,000 m{sup 3} of macrophytes harvested each season. These are mainly Ulva rigida and Gracilaria confervoides. In the experiments A and SS were mixed at different ratios (20 - 40% algae, TS basis) and fed to mesophilic (37C) and thermophilic (55C) digesters which operated at 11- to 15-day hydraulic retention times and 1.7 - 4.4 kgTVS/ m{sup 3}/day organic loading rates. It was concluded that the mesophilic co-digestion process is applicable with potentialities of around 30% of the present SS flow-rate. Thermophilic digestion is not possible, because of the inhibition of methanogens probably due to the activity of sulphate-reducers

  3. Anaerobic digestion of municipal solid waste as a treatment prior to landfill

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, P.H.L.; Kuruparan, P.; Visvanathan, C. [Asian Institute of Technology, Pathumthani (Thailand). Environmental Engineering and Management Program

    2007-02-15

    Anaerobic digestion of organic fraction of municipal solid waste was conducted in pilot-scale reactor based on high-solid combined anaerobic digestion process. This study was performed in two runs. In Run1 and Run 2, pre-stage flushing and micro-aeration were conducted to determine their effect in terms of enhancing hydrolysis and acidification in ambient condition. In Run 2, after pre-stage, the methane phase (methanogenesis) was started-up after pH adjustment and inoculum addition in mesophilic condition. Acidified leachate produced in pre-stage was used for percolation during active methane phase. At the end of methane phase, air flushing was conducted before unloading the digesters. Hydrolysis an acidification yield of 140 g C/kg TS and 180 g VFA/kg TS were achieved, respectively in pre-stage. Micro-aeration exhibited an equivocal result in terms of enhancing hydrolysis/acidification; however it showed a positive effect in methane phase performance and this needed further investigation. Leachate percolation during methane phase showed an enhanced methanization when compared to the reactors without leachate percolation. After 60 days, 260 l CH{sub 4}/kg VS was obtained. Based on the waste methane potential, 75% biogas conversion and 61% VS degradation were achieved. (author)

  4. An integrated approach to energy recovery from biomass and waste: Anaerobic digestion-gasification-water treatment.

    Science.gov (United States)

    Milani, M; Montorsi, L; Stefani, M

    2014-07-01

    The article investigates the performance of an integrated system for the energy recovery from biomass and waste based on anaerobic digestion, gasification and water treatment. In the proposed system, the organic fraction of waste of the digestible biomass is fed into an anaerobic digester, while a part of the combustible fraction of the municipal solid waste is gasified. Thus, the obtained biogas and syngas are used as a fuel for running a cogeneration system based on an internal combustion engine to produce electric and thermal power. The waste water produced by the integrated plant is recovered by means of both forward and inverse osmosis. The different processes, as well as the main components of the system, are modelled by means of a lumped and distributed parameter approach and the main outputs of the integrated plant such as the electric and thermal power and the amount of purified water are calculated. Finally, the implementation of the proposed system is evaluated for urban areas with a different number of inhabitants and the relating performance is estimated in terms of the main outputs of the system.

  5. 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.

  6. Timeline of bio-hydrogen production by anaerobic digestion of biomass

    Directory of Open Access Journals (Sweden)

    Bernadette E. TELEKY

    2015-12-01

    Full Text Available Anaerobic digestion of biomass is a process capable to produce biohydrogen, a clean source of alternative energy. Lignocellulosic biomass from agricultural waste is considered a renewable energy source; therefore its utilization also contributes to the reduction of water, soil and air pollution. The study consists in five consecutive experiments designed to utilize anaerobic bacterial enrichment cultures originating from the Hungarian Lake, Hévíz. Wheat straw was used as complex substrate to produce hydrogen. The timeline evolution of hydrogen production was analyzed and modelled by two functions: Logistic and Boltzmann. The results proved that hydrogen production is significant, with a maximum of 0.24 mlN/ml and the highest hydrogen production occurs between the days 4-10 of the experiment.

  7. Simulation of DEHP biodegradation and sorption during the anaerobic digestion of secondary sludge

    DEFF Research Database (Denmark)

    Fountoulakis, M.S.; Stamatelatou, K.; Batstone, Damien J.

    2006-01-01

    -limiting for the compound biodegradation. In this study, the anaerobic biodegradation of DEHP was investigated through batch kinetic experiments and dynamic transitions of a continuous stirred tank reactor (CSTR) fed with secondary sludge contaminated with DEHP. A widely accepted model (ADM1) was used to fit the anaerobic...... digestion of secondary sludge and was properly extended to. account for DEHP removal, in which mass transfer processes are also involved. It was shown that DEHP removal was limited by the transfer of DEHP within the solid fraction. The criterion selected for the distinction of the two sites was whether......" against biodegradation. The model, fitted to the batch experimental data, was able to predict DEHP removal in the CSTR operated at various HRTs....

  8. Carbohydrate-enriched cyanobacterial biomass as feedstock for bio-methane production through anaerobic digestion

    DEFF Research Database (Denmark)

    Markou, Giorgos; Angelidaki, Irini; Georgakakis, Dimitris

    2013-01-01

    The anaerobic digestion performance using carbohydrate-enriched biomass of Arthrospira platensis was studied. The carbohydrate enrichment was achieved after the cultivation of A. platensis under phosphorus limitation conditions. Three biomass compositions (60%, 40% and 20% carbohydrates content) ...

  9. Anaerobic co-digestion of water hyacinth and cow dung for biogas production

    OpenAIRE

    OROKA FRANK OKE; AKHIHIERO THELMA

    2015-01-01

    Co-digestion of water hyacinth and cow dung under anaerobic condition was studied. Results indicate a progressive increase in biogas yield with increased cow dung in the co-ferment mixture of water hyacinth: cow dung

  10. Monitoring of volatile fatty acids during anaerobic digestion using a microbial electrochemical sensor

    DEFF Research Database (Denmark)

    Jin, Xiangdan; Angelidaki, Irini; Zhang, Yifeng

    2016-01-01

    innovatively which was separated from the anode chamber by an anion exchange membrane. The detection range can be broadened as only part of the ionized VFAs can transport through the membrane and the biofilm can be protected from inhibitors and toxicants. The correlation between current densities and VFA......Volatile fatty acid (VFA) concentration is known as an important indicator to control and optimize anaerobic digestion (AD) process. In this study, an innovative VFA biosensor was developed based on the principle of a microbial desalination cell. The bulk substrate was dosed into the middle chamber...

  11. Feasibility of anaerobic digested corn stover as biosorbent for heavy metal.

    Science.gov (United States)

    Wang, Jin; Peng, Shu-chuan; Wan, Zheng-qiang; Yue, Zheng-bo; Wu, Jian; Chen, Tian-hu

    2013-03-01

    Anaerobic digested (AD) corn stover collected from a lab-scale reactor was used as bioadsorbent to remove the heavy metal in aqueous solution. Effects of contact time and initial heavy metal concentrations on the removal process of Cu(2+) and Cd(2+) were investigated. The maximum adsorption capacities of AD corn stover obtained from Langmuir isotherm models were 83.3 and 50.0mg/g for Cu(2+) and Cd(2+), respectively. Fourier transform infrared spectroscopy (FTIR) was also used to investigate the surface characteristic of raw and heavy metal loaded AD corn stover.

  12. Ethanol production from maize silage as lignocellulosic biomass in anaerobically digested and wet-oxidized manure

    DEFF Research Database (Denmark)

    Oleskowicz-Popiel, Piotr; Lisiecki, P.; Holm-Nielsen, J.B.

    2008-01-01

    In this communication, pretreatment of the anaerobically digested (AD) manure and the application of the pretreated AD manure as liquid medium for the simultaneous saccharification and fermentation (SSF) were described. Furthermore, fermentation of pretreated maize silage and wheat straw....... No extra nitrogen source was needed in the fermentation broth. It was shown that the AD manure could successfully substitute process water in SSF of pretreated lignocellulosic fibres. Theoretical ethanol yields of 82% were achieved, giving 30.8 kg ethanol per 100 kg dry mass of maize silage. (C) 2007...

  13. Hybrid neural modelling of an anaerobic digester with respect to biological constraints.

    Science.gov (United States)

    Karama, A; Bernard, O; Gouzé, J L; Benhammou, A; Dochain, D

    2001-01-01

    A hybrid model for an anaerobic digestion process is proposed. The fermentation is assumed to be performed in two steps, acidogenesis and methanogenesis, by two bacterial populations. The model is based on mass balance equations, and the bacterial growth rates are represented by neural networks. In order to guarantee the biological meaning of the hybrid model (positivity of the concentrations, boundedness, saturation or inhibition of the growth rates) outside the training data set, a method that imposes constraints in the neural network is proposed. The method is applied to experimental data from a fixed bed reactor.

  14. Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Semi-annual report

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, S; Farooq, S; Gerrish, H P; Wong, K F; Daly, Jr, E L; Chriswell, C

    1980-02-01

    Anaerobic digestion of municipal waste has been demonstrated to be feasible in bench scale experiments by Pfeffer (1974). Approximately, 50% reduction in mass and production of 6000 ft/sup 3/ of gas/ton have been estimated. The gas composition is estimated to be 50% methane and 50% carbon monoxide. The technical and economic feasibility of anaerobic digestion with an ultimate objective of commercialization are discussed. A plant has been built at Pompano Beach, Florida on an existing shredding and landfill operation site. The plant design capacity is 100 tons/day. Two digesters have been constructed to be used in parallel. The process consists of primary shredding, metal separation, secondary shredding, air classification and digestion of light fraction. Sewage sludge was used to seed the initial mixture in the digester. The output slurry is vacuum filtered and the filter cake disposed on an existing landfill. The filtrate is recycled. Excess filtrate is sprayed on the landfill. At present the output gas is being flared. A flow chart for the plant is presented. It is imperative that environmental investigations be conducted on new energy technology prior to commercialization. A project was initiated to characterize all input and output streams and to assess the potential for ground water contamination by landfill disposal of effluents. Detailed chemical, biological and physical characterization efforts supported by leaching and modelling studies are being conducted to achieve the stated objectives. Some mutagenic studies were also conducted. The environmental investigations were started in August 1978. Sengupta et al (1979a) reported the first year's efforts.

  15. Determination of Methane and Carbon Dioxide Formation Rate Constants for Semi-Continuously Fed Anaerobic Digesters

    Directory of Open Access Journals (Sweden)

    Jan Moestedt

    2015-01-01

    Full Text Available To optimize commercial-scale biogas production, it is important to evaluate the performance of each microbial step in the anaerobic process. Hydrolysis and methanogenesis are usually the rate-limiting steps during digestion of organic waste and by-products. By measuring biogas production and methane concentrations on-line in a semi-continuously fed reactor, gas kinetics can be evaluated. In this study, the rate constants of the fermentative hydrolysis step (kc and the methanogenesis step (km were determined and evaluated in a continuously stirred tank laboratory-scale reactor treating food and slaughterhouse waste and glycerin. A process additive containing Fe2+, Co2+ and Ni2+ was supplied until day 89, after which Ni2+ was omitted. The omission resulted in a rapid decline in the methanogenesis rate constant (km to 70% of the level observed when Ni2+ was present, while kc remained unaffected. This suggests that Ni2+ mainly affects the methanogenic rather than the hydrolytic microorganisms in the system. However, no effect was initially observed when using conventional process monitoring parameters such as biogas yield and volatile fatty acid concentration. Hence, formation rate constants can reveal additional information on process performance and km can be used as a complement to conventional process monitoring tools for semi-continuously fed anaerobic digesters.

  16. Biodegradability of wastewater and activated sludge organics in anaerobic digestion.

    Science.gov (United States)

    Ikumi, D S; Harding, T H; Ekama, G A

    2014-06-01

    The investigation provides experimental evidence that the unbiodegradable particulate organics fractions of primary sludge and waste activated sludge calculated from activated sludge models remain essentially unbiodegradable in anaerobic digestion. This was tested by feeding the waste activated sludge (WAS) from three different laboratory activated sludge (AS) systems to three separate anaerobic digesters (AD). Two of the AS systems were Modified Ludzack - Ettinger (MLE) nitrification-denitrification (ND) systems and the third was a membrane University of Cape Town (UCT) ND and enhanced biological P removal system. One of the MLE systems and the UCT system were fed the same real settled wastewater. The other MLE system was fed raw wastewater which was made by adding a measured constant flux (gCOD/d) of macerated primary sludge (PS) to the real settled wastewater. This PS was also fed to a fourth AD and a blend of PS and WAS from settled wastewater MLE system was fed to a fifth AD. The five ADs were each operated at five different sludge ages (10-60d). From the measured performance results of the AS systems, the unbiodegradable particulate organic (UPO) COD fractions of the raw and settled wastewaters, the PS and the WAS from the three AS systems were calculated with AS models. These AS model based UPO fractions of the PS and WAS were compared with the UPO fractions calculated from the performance results of the ADs fed these sludges. For the PS, the UPO fraction calculated from the AS and AD models matched closely, i.e. 0.30 and 0.31. Provided the UPO of heterotrophic (OHO, fE_OHO) and phosphorus accumulating (PAO, fE_PAO) biomass were accepted to be those associated with the death regeneration model of organism "decay", the UPO of the WAS calculated from the AS and AD models also matched well - if the steady state AS model fE_OHO = 0.20 and fE_PAO = 0.25 values were used, then the UPO fraction of the WAS calculated from the AS models deviated significantly

  17. 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.

  18. 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.

  19. Modelling anaerobic co-digestion in Benchmark Simulation Model No. 2: Parameter estimation, substrate characterisation and plant-wide integration.

    Science.gov (United States)

    Arnell, Magnus; Astals, Sergi; Åmand, Linda; Batstone, Damien J; Jensen, Paul D; Jeppsson, Ulf

    2016-07-01

    Anaerobic co-digestion is an emerging practice at wastewater treatment plants (WWTPs) to improve the energy balance and integrate waste management. Modelling of co-digestion in a plant-wide WWTP model is a powerful tool to assess the impact of co-substrate selection and dose strategy on digester performance and plant-wide effects. A feasible procedure to characterise and fractionate co-substrates COD for the Benchmark Simulation Model No. 2 (BSM2) was developed. This procedure is also applicable for the Anaerobic Digestion Model No. 1 (ADM1). Long chain fatty acid inhibition was included in the ADM1 model to allow for realistic modelling of lipid rich co-substrates. Sensitivity analysis revealed that, apart from the biodegradable fraction of COD, protein and lipid fractions are the most important fractions for methane production and digester stability, with at least two major failure modes identified through principal component analysis (PCA). The model and procedure were tested on bio-methane potential (BMP) tests on three substrates, each rich on carbohydrates, proteins or lipids with good predictive capability in all three cases. This model was then applied to a plant-wide simulation study which confirmed the positive effects of co-digestion on methane production and total operational cost. Simulations also revealed the importance of limiting the protein load to the anaerobic digester to avoid ammonia inhibition in the digester and overloading of the nitrogen removal processes in the water train. In contrast, the digester can treat relatively high loads of lipid rich substrates without prolonged disturbances.

  20. Microbial trophic interactions and mcrA gene expression in monitoring of anaerobic digesters

    Science.gov (United States)

    Alvarado, Alejandra; Montañez-Hernández, Lilia E.; Palacio-Molina, Sandra L.; Oropeza-Navarro, Ricardo; Luévanos-Escareño, Miriam P.; Balagurusamy, Nagamani

    2014-01-01

    Anaerobic digestion (AD) is a biological process where different trophic groups of microorganisms break down biodegradable organic materials in the absence of oxygen. A wide range of AD technologies is being used to convert livestock manure, municipal and industrial wastewaters, and solid organic wastes into biogas. AD gains importance not only because of its relevance in waste treatment but also because of the recovery of carbon in the form of methane, which is a renewable energy and is used to generate electricity and heat. Despite the advances on the engineering and design of new bioreactors for AD, the microbiology component always poses challenges. Microbiology of AD processes is complicated as the efficiency of the process depends on the interactions of various trophic groups involved. Due to the complex interdependence of microbial activities for the functionality of the anaerobic bioreactors, the genetic expression of mcrA, which encodes a key enzyme in methane formation, is proposed as a parameter to monitor the process performance in real time. This review evaluates the current knowledge on microbial groups, their interactions, and their relationship to the performance of anaerobic biodigesters with a focus on using mcrA gene expression as a tool to monitor the process. PMID:25429286

  1. Bio-energy conversion performance, biodegradability, and kinetic analysis of different fruit residues during discontinuous anaerobic digestion.

    Science.gov (United States)

    Zhao, Chen; Yan, Hu; Liu, Yan; Huang, Yan; Zhang, Ruihong; Chen, Chang; Liu, Guangqing

    2016-06-01

    Huge amounts of fruit residues are produced and abandoned annually. The high moisture and organic contents of these residues makes them a big problem to the environment. Conversely, they are a potential resource to the world. Anaerobic digestion is a good way to utilize these organic wastes. In this study, the biomethane conversion performances of a large number of fruit residues were determined and compared using batch anaerobic digestion, a reliable and easily accessible method. The results showed that some fruit residues containing high contents of lipids and carbohydrates, such as loquat peels and rambutan seeds, were well fit for anaerobic digestion. Contrarily, residues with high lignin content were strongly recommended not to be used as a single substrate for methane production. Multiple linear regression model was adopted to simulate the correlation between the organic component of these fruit residues and their experimental methane yield, through which the experimental methane yield could probably be predicted for any other fruit residues. Four kinetic models were used to predict the batch anaerobic digestion process of different fruit residues. It was shown that the modified Gompertz and Cone models were better fit for the fruit residues compared to the first-order and Fitzhugh models. The first findings of this study could provide useful reference and guidance for future studies regarding the applications and potential utilization of fruit residues.

  2. Anaerobic digestion and digestate use: accounting of greenhouse gases and global warming contribution

    DEFF Research Database (Denmark)

    Møller, Jacob; Boldrin, Alessio; Christensen, Thomas Højlund

    2009-01-01

    Anaerobic digestion (AD) of source-separated municipal solid waste (MSW) and use of the digestate is presented from a global warming (GW) point of view by providing ranges of greenhouse gas (GHG) emissions that are useful for calculation of global warming factors (GWFs), i.e. the contribution to ...... highly influenced the result. In comparison with the few published GWFs for AD, the range of our data was much larger demonstrating the need to use a consistent and robust approach to GHG accounting and simultaneously accept that some key parameters are highly uncertain....... measured in CO2-equivalents per tonne of wet waste. The GHG accounting was done by distinguishing between direct contributions at the AD facility and indirect upstream or downstream contributions. GHG accounting for a generic AD facility with either biogas utilization at the facility or upgrading...... of the gas for vehicle fuel resulted in a GWF from —375 (a saving) to 111 (a load) kg CO2-eq. tonne—1 wet waste. In both cases the digestate was used for fertilizer substitution. This large range was a result of the variation found for a number of key parameters: energy substitution by biogas, N2O...

  3. Biodegradation of phthalate esters during the mesophilic anaerobic digestion of sludge

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Alatriste-Mondragon, Felipe; Iranpour, R.

    2003-01-01

    Phthalic acid esters (PAE) are commonly found in the sludge generated in the wastewater treatment plants. Anaerobic digestion followed by land application is a common treatment and disposal practice of sludge. To date, many studies exist on the anaerobic biodegradation rates of PAE, especially...

  4. Rheology of sludge from double phase anaerobic digestion of organic fraction of municipal solid waste.

    Science.gov (United States)

    Battistoni, P; Pavan, P; Mata-Alvarez, J; Prisciandaro, M; Cecchi, F

    2000-01-01

    In this paper experimental results on the anaerobic digestion of sewage sludge and organic fraction of municipal solid waste (OFMSW) by using a double phase process are reported. The long-term experiment has been carried out on a pilot scale plant, performed in different sets of operative conditions, during which granulometric distributions of particles in sludges and rheological properties of sludges were monitored. A significant fluidification of sludge was evidenced in the meso-thermo process, especially taking into account the variation in sludge behaviour from the first to the second phase. In the thermo-thermo process a fluidification higher than that shown in meso-thermo conditions is not observed, this suggesting that better results in terms of sludge conditioning can be obtained in a long time spent in thermophilic anaerobic digestion. Total volatile solids (TVS) and total fixed solids (TFS) become the most important parameters when mathematical modelling is applied to these processes. In the acidogenic phase, hydraulic retention time (HRT) and temperature are used to determine rigidity coefficient (RC), while only temperature is needed for yield stress (YC). Organic loading rate (OLR) and specific gas production (SGP) exert an important role in methanogenic phase description.

  5. 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.

  6. Dairy manure resource recovery utilizing two-stage anaerobic digestion - Implications of solids fractionation.

    Science.gov (United States)

    Stowe, Edmond J; Coats, Erik R; Brinkman, Cynthia K

    2015-12-01

    Dairy manure management is increasingly becoming an environmental challenge. In this regard, manure anaerobic digestion (AD) can be applied to address environmental concerns; however, dairy manure AD remains economically uncompetitive. Ongoing research is focused on enhanced resource recovery from manure, including maximizing AD methane yield through a novel multi-stage AD configuration. Research presented herein centered on the hypothesis that separately digesting fine and coarse solids from fermented dairy manure would improve methane production; the hypothesis was disproven. While maximum methane concentration was realized on fine solids, combined solids AD yielded enhanced VS destruction. The diverse combined-solids substrate enriched for a more heterogeneous bacterial/archaeal consortium that balanced fermentation and methanogenesis to yield maximum product (methane). However, results suggest that targeted AD of the fat-rich fine solids could be a more optimal approach for processing manure; alternate (non-AD) methods could then be applied to extract value from the fibrous fraction.

  7. Community Anaerobic Digester: Powered by Students and Driving Practical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Richmond Hall, Joan [Vermont Sustainable Jobs Fund, Montpelier, VT (United States); O' Leary, Mary [Vermont Sustainable Jobs Fund, Montpelier, VT (United States)

    2016-03-23

    The Vermont Tech Community Anaerobic Digester (VTCAD) was conceived and funded by a partnership of educational, agricultural, waste management and environmental groups to create a living laboratory demonstrating the value of recycling nutrients, renewable energy and agricultural co-products from organic wastes. VTCAD was constructed on the Randolph Center, Vermont campus of Vermont Tech, a public college offering engineering technology, agricultural, renewable energy education and workforce training. With funding from the U.S. Department of Energy (DOE), the Vermont State Colleges and others, construction was completed in early 2014 and the facility has been operational since April 2014. At full power, VTCAD uses 16,000 gallons of manure and organic residuals to produce 8,880 kilowatt hours (kWh) of electricity per day, ‘waste’ heat that will be used to heat four campus buildings, bedding material for the college dairy herds and recycled nutrients used as crop fertilizer. VTCAD uses a mixture of manure from co-managed farms and organic residuals collected from the community. Feedstock materials include brewery residuals, the glycerol by-product of biodiesel production from waste cooking oil, grease trap waste, and waste paper and, soon, locally collected pre- and post-consumer food residuals.

  8. Anaerobic digestion of giant reed for methane production.

    Science.gov (United States)

    Yang, Liangcheng; Li, Yebo

    2014-11-01

    As a fast growing plant, giant reed has good potential to be used as a feedstock for methane production via anaerobic digestion (AD). The effect of total solids (TS) content, an AD operating parameter, was studied. Results showed that increasing TS from 8% to 38% decreased methane yield, due to the inhibition of volatile fatty acids (VFAs) and total ammonia nitrogen (TAN); while the maximum volumetric methane production was obtained at 20-23% TS. Comparison of solid-state AD (SS-AD) at 20% TS and liquid AD (L-AD) at 8% TS was conducted at feedstock to effluent (F/E) ratios of 2.0, 3.5, and 5.0. The best performance was achieved at an F/E of 2.0, with methane yields of 129.7 and 150.8L-CH4/kg-VS for SS-AD and L-AD, respectively. Overall organic components were degraded by 17.7-28.5% and 24.0-26.6% in SS-AD and L-AD, respectively; among which cellulose showed the highest degradation rate and the highest contribution to methane production.

  9. Treatment of wine distillery wastewater by high rate anaerobic digestion.

    Science.gov (United States)

    Melamane, X L; Tandlich, R; Burgess, I E

    2007-01-01

    Wine distillery wastewaters (WDW) are acidic and have a high content of potential organic pollutants. This causes high chemical oxygen demand (COD) values. Polyphenols constitute a significant portion of this COD, and limit the efficiency of biological treatment of WDWs. WDW starting parameters were as follows: pH 3.83, 4,185 mg/l soluble COD (COD(s)) and 674.6 mg/l of phenols. During operation, amendments of CaCO3 and K2HPO4, individually or in combination, were required for buffering the digester. Volatile fatty acid concentrations were < 300 mg/l throughout the study, indicating degradation of organic acids present. Mean COD(s) removal efficiency for the 130 day study was 87%, while the mean polyphenol, removal efficiency was 63%. Addition of 50 mg/l Fe(3+) between days 86 and 92 increased the removal efficiencies of COD(s) to 97% and of polyphenols to 65%. Addition of Co(3+) improved removal efficiencies to 97% for COD(s) and 92% for polyphenols. Optimization of anaerobic treatment was achieved at 30% WDW feed strength. Removal efficiencies of 92% and 84% were recorded at increased feed strength from days 108 to 130. High removal efficiencies of COD(s) and polyphenols after day 82 were attributed to the addition of macronutrients and micronutrients that caused pH stability and thus stimulated microbial activity.

  10. The future of anaerobic digestion and biogas utilization.

    Science.gov (United States)

    Holm-Nielsen, J B; Al Seadi, T; Oleskowicz-Popiel, P

    2009-11-01

    One of the common tendencies of animal production activities in Europe and in developed countries in general is to intensify the animal production and to increase the size of the animal production units. High livestock density is always accompanied by production of a surplus of animal manure, representing a considerable pollution threat for the environment in these areas. Avoiding over-fertilization is not only important for environmental protection reasons but also for economical reasons. Intensive animal production areas need therefore suitable manure management, aiming to export and to redistribute the excess of nutrients from manure and to optimize their recycling. Anaerobic digestion of animal manure and slurries offers several benefits by improving their fertilizer qualities, reducing odors and pathogens and producing a renewable fuel - the biogas. The EU policies concerning renewable energy systems (RES) have set forward a fixed goal of supplying 20% of the European energy demands from RES by year 2020. A major part of the renewable energy will originate from European farming and forestry. At least 25% of all bioenergy in the future can originate from biogas, produced from wet organic materials such as: animal manure, whole crop silages, wet food and feed wastes, etc.

  11. Optimization of anaerobic digestion of a mixture of Zea mays and Miscanthus sacchariflorus silages with various pig manure dosages.

    Science.gov (United States)

    Bułkowska, K; Pokój, T; Klimiuk, E; Gusiatin, Z M

    2012-12-01

    Digestion of crop silage (Zea mays L. and Miscanthus sacchariflorus) with 0%, 7.5%, 12.5% and 25% pig manure as co-substrate was performed in continuous stirred-tank reactors, for a constant hydraulic retention time of 45 d and organic load rate of 2.1 g L(-1)d(-1). A matrix of correlations between biogas/methane production and parameters of anaerobic digestion was created in order to estimate process stability. The values of the correlation coefficients indicated that the most stable anaerobic digestion was achieved using 7.5% and 12.5% pig manure. In contrast, the positive correlation between ammonium and volatile fatty acids (r=0.8698, psilage alone, pig manure favored the production of biogas and methane; the highest production rates were obtained with 12.5% pig manure.

  12. Waste activated sludge treatment based on temperature staged and biologically phased anaerobic digestion system.

    Science.gov (United States)

    Yu, Jingwen; Zheng, Mingxia; Tao, Tao; Zuo, Jiane; Wang, Kaijun

    2013-10-01

    The concept of temperature staged and biological phased (TSBP) was proposed to enhance the performance of waste-activated sludge anaerobic digestion. Semi-continuous experiments were used to investigate the effect of temperature (35 to 70 degrees C) as well as the hydraulic retention time (HRT) (2, 4 and 6 days) on the acidogenic phase. The results showed that the solubilization degree of waste-activated sludge increased from 14.7% to 30.1% with temperature increasing from 35 to 70 degrees C, while the acidification degree was highest at 45 degrees C (17.6%), and this was quite different from the temperature impact on hydrolysis. Compared with HRT of 2 and 6 days, 4 days was chosen as the appropriate HRT because of its relatively high solubilization degree (24.6%) and acidification degree (20.1%) at 45 degrees C. The TSBP system combined the acidogenic reactor (45 degrees C, 4 days) with the methanogenic reactor (35 degrees C, 16 days) and the results showed 84.8% and 11.4% higher methane yield and volatile solid reduction, respectively, compared with that of the single-stage anaerobic digestion system with HRT of 20 days at 35 degrees C. Moreover, different microbial morphologies were observed in the acidogenic- and methanogenic-phase reactors, which resulted from the temperature control and HRT adjustment. All the above results indicated that 45 degrees C was the optimum temperature to inhibit the activity of methanogenic bacteria in the acidogenic phase, and temperature staging and phase separation was thus accomplished. The advantages of the TSBP process were also confirmed by a full-scale waste-activated sludge anaerobic digestion project which was an energy self-sufficient system.

  13. 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.

  14. Microbial reduction of sulfur dioxide with anaerobically digested municipal sewage biosolids as electron donors.

    Science.gov (United States)

    Selvaraj, P T; Sublette, K L

    1995-01-01

    A concentrated stream of sulfur dioxide (SO2) is produced by regeneration of the sorbent in certain new regenerable processes for the desulfurization of flue gas. We have previously proposed that this SO2 can be converted to elemental sulfur for disposal or byproduct recovery using a microbial/Claus process. In this process, two-thirds of the SO2-reducing gas stream would be contacted with a mixed culture containing sulfate-reducing bacteria (SRB), where SO2 would act as an electron acceptor with reduction to hydrogen sulfide (H2S). This H2S could then be recombined with the remaining SO2 and sent to a Claus unit to produce elemental sulfur. The sulfate-reducing bacterium, Desulfovibrio desulfuricans, has been immobilized by coculture with flocforming heterotrophs from an anaerobic digester, resulting in a SO2-reducing floc that may be collected from the effluent of a continuous reactor for recycle by gravity sedimentation. The carbon and energy source for these cultures was anaerobically digested municipal sewage solids. The maximum specific activity for SO2 reduction in these cultures, in terms of dry weight of D. desulfuricans biomass, was 9.1 mmol of SO2/h.g. The stoichiometry with respect to the electron donor was 15.5 mg of soluble COD/mmol of SO2 reduced.

  15. Calculaton of heat transfer at keeping the temperature of anaerobic digestion%保持厌氧消化温度的传热计算

    Institute of Scientific and Technical Information of China (English)

    张立奎

    2015-01-01

    In the winter the sewage temperature of anaerobic digester will drop to 10℃or even lower. Anaero-bic digestion is difficult to run because lower temperature will impede anaerobic digestion ,so it will be neces-sary to heat the sewage of anaerobic digester. This is an unsteady process of heat transfer. In the process the anaerobic digester sewage will be heated with the saturated steam and the hot water in the external shell-and-tube heat exchanger until a steady digestion temperature is attained. This paper provides the calculation process and its programs of heat transfer. Also, two typical examples are provided to better demonstrate in detail the cal-culation processes in the latter of this paper.%在冬季,厌氧池污水温度降至10℃乃至以下,厌氧消化难以运行,因为低温阻碍厌氧消化进行,所以需要对厌氧池污水加热.这是个不稳定传热过程.文中提供了用外置式列管换热器,以饱和水蒸汽和热水加热厌氧池循环污水至稳定消化温度的传热过程计算及其计算程序,文末还以两个典型示例详述了计算过程.

  16. Anaerobic digestion of Chinese cabbage waste silage with swine manure for biogas production: batch and continuous study.

    Science.gov (United States)

    Kafle, Gopi Krishna; Bhattarai, Sujala; Kim, Sang Hun; Chen, Lide

    2014-01-01

    The aim of this study was to investigate the potential for anaerobic co-digestion of Chinese cabbage waste silage (CCWS) with swine manure (SM). Batch and continuous experiments were carried out under mesophilic anaerobic conditions (36-38°C). The batch test evaluated the effect of CCWS co-digestion with SM (SM: CCWS=100:0; 25:75; 33:67; 0:100, % volatile solids (VS) basis). The continuous test evaluated the performance of a single stage completely stirred tank reactor with SM alone and with a mixture of SM and CCWS. Batch test results showed no significant difference in biogas yield up to 25-33% of CCWS; however, biogas yield was significantly decreased when CCWS contents in feed increased to 67% and 100%. When testing continuous digestion, the biogas yield at organic loading rate (OLR) of 2.0 g VSL⁻¹ d⁻¹ increased by 17% with a mixture of SM and CCWS (SM:CCWS=75:25) (423 mL g⁻¹ VS) than with SM alone (361 mL g⁻¹ VS). The continuous anaerobic digestion process (biogas production, pH, total volatile fatty acids (TVFA) and TVFA/total alkalinity ratios) was stable when co-digesting SM and CCWS (75:25) at OLR of 2.0 g VSL⁻¹ d⁻¹ and hydraulic retention time of 20 days under mesophilic conditions.

  17. Dry co-digestion of sewage sludge and rice straw under mesophilic and thermophilic anaerobic conditions.

    Science.gov (United States)

    Chu, Xiangqian; Wu, Guangxue; Wang, Jiaquan; Hu, Zhen-Hu

    2015-12-01

    Dry anaerobic digestion of sewage sludge can recover biogas as energy; however, its low C/N ratio limits it as a single substrate in the anaerobic digestion. Rice straw is an abundant agricultural residue in China, which is rich in carbon and can be used as carbon source. In the present study, the performance of dry co-digestion of sewage sludge and rice straw was investigated under mesophilic (35 °C) and thermophilic (55 °C) conditions. The operational factors impacting dry co-digestion of sewage sludge and rice straw such as C/N ratio, moisture content, and initial pH were explored under mesophilic conditions. The results show that low C/N ratios resulted in a higher biogas production rate, but a lower specific biogas yield; low moisture content of 65 % resulted in the instability of the digestion system and a low specific biogas yield. Initial pH ranging 7.0-9.0 did not affect the performance of the anaerobic digestion. The C/N ratio of 26-29:1, moisture content of 70-80 %, and pH 7.0-9.0 resulted in good performance in the dry mesophilic co-digestion of sewage sludge and rice straw. As compared with mesophilic digestion, thermophilic co-digestion of sewage sludge and rice straw significantly enhanced the degradation efficiency of the substrates and the specific biogas yield (p co-digestion of sewage sludge under mesophilic and thermophilic conditions.

  18. Economic analysis of anaerobic digestion - A case of Green power biogas plant in The Netherlands

    NARCIS (Netherlands)

    Gebrezgabher, S.A.; Meuwissen, M.P.M.; Prins, B.A.M.; Oude Lansink, A.G.J.M.

    2010-01-01

    One of the key concerns of biogas plants is the disposal of comparatively large amounts of digestates in an economically and environmentally sustainable manner. This paper analyses the economic performance of anaerobic digestion of a given biogas plant based on net present value (NPV) and internal r

  19. Mesophilic anaerobic co-digestion of municipal solid waste and sewage sludge

    DEFF Research Database (Denmark)

    Aghdam, Ehsan Fathi; Kinnunen, V.; Rintala, Jukka A.

    2015-01-01

    This paper presents mesophilic anaerobic digestion (AD) of organic fraction of municipal solid waste (OFMSW), biowaste (BW), sewage sludge (SS), and co-digestion of BW and SS. Average methane yields of 386 ± 54, 385 ± 82, 198 ± 14, and 318 ± 59 L CH4/kg volatile solids (VS) were obtained for OFMSW...

  20. State Of The Science On Cogeneration Of Heat And Power From Anaerobic Digestion Of Municipal Biosolids

    Science.gov (United States)

    This presentation will report on work underway to inventory facilities currently utilizing biogas from anaerobic digestion and speak with practitioners to learn: techniques for preparing residuals for digestion, methods to use for cleaning biogas (e.g., of siloxane), and how gas...

  1. The potential of surplus grass production as co-substrate for anaerobic digestion

    DEFF Research Database (Denmark)

    Meyer, Ane Katharina Paarup; Schleier, Caroline; Piorr, Hans Peter;

    2016-01-01

    . Furthermore, it could provide incentives for establishing new biogas plants in the region and thereby increase the share of manure being digested anaerobically, which could help extrapolate the environmental and climate related benefits documented for the use of digested animal manure as fertilizer...

  2. Anaerobic Digestion II. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

    Science.gov (United States)

    Arasmith, E. E.

    This lesson is the second of a two-part series on anaerobic digestion. Topics discussed include classification of digester by function, roof design, and temperature range, mixing systems, gas system components, operational control basics, and general safety considerations. The lesson includes an instructor's guide and student workbook. The…

  3. Enhanced mesophilic anaerobic digestion of food waste by thermal pretreatment: Substrate versus digestate heating.

    Science.gov (United States)

    Ariunbaatar, Javkhlan; Panico, Antonio; Yeh, Daniel H; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2015-12-01

    Food waste (FW) represents a source of high potential renewable energy if properly treated with anaerobic digestion (AD). Pretreating the substrates could yield a higher biomethane production in a shorter time. In this study, the effects of thermal (heating the FW in a separate chamber) and thermophilic (heating the full reactor content containing both FW and inoculum) pretreatments at 50, 60, 70 and 80°C prior to mesophilic AD were studied through a series of batch experiments. Pretreatments at a lower temperature (50°C) and a shorter time (55°C) and longer operating times (>12h) yielded higher soluble chemical oxygen demand (CODs), but had a negative effect on the methanogenic activity. The thermal pretreatments at the same conditions resulted in a lower solubilization of COD. Based on net energy calculations, the enhanced biomethane production is sufficient to heat up the FW for the thermal, but not for the thermophilic pretreatment.

  4. Increased anaerobic production of methane by co-digestion of sludge with microalgal biomass and food waste leachate.

    Science.gov (United States)

    Kim, Jungmin; Kang, Chang-Min

    2015-01-01

    The co-digestion of multiple substrates is a promising method to increase methane production during anaerobic digestion. However, limited reliable data are available on the anaerobic co-digestion of food waste leachate with microalgal biomass. This report evaluated methane production by the anaerobic co-digestion of different mixtures of food waste leachate, algal biomass, and raw sludge. Co-digestion of substrate mixture containing equal amounts of three substrates had higher methane production than anaerobic digestion of individual substrates. This was possibly due to a proliferation of methanogens over the entire digestion period induced by multistage digestion of different substrates with different degrees of degradability. Thus, the co-digestion of food waste, microalgal biomass, and raw sludge appears to be a feasible and efficient method for energy conversion from waste resources.

  5. The environmental sustainability of anaerobic digestion as a biomass valorization technology.

    Science.gov (United States)

    De Meester, Steven; Demeyer, Jens; Velghe, Filip; Peene, Andy; Van Langenhove, Herman; Dewulf, Jo

    2012-10-01

    This paper studies the environmental sustainability of anaerobic digestion from three perspectives. First, reference electricity is compared to electricity production from domestic organic waste and energy crop digestion. Second, different digester feed possibilities in an agricultural context are studied. Third, the influence of applying digestate as fertilizer is investigated. Results highlight that biomass is converted at a rational exergy (energy) efficiency ranging from 15.3% (22.6) to 33.3% (36.0). From a life cycle perspective, a saving of over 90% resources is achieved in most categories when comparing biobased electricity to conventional electricity. However, operation without heat valorization results in 32% loss of this performance while using organic waste (domestic and agricultural residues) as feedstock avoids land resources. The use of digestate as a fertilizer is beneficial from a resource perspective, but causes increased nitrogen and methane emissions, which can be reduced by 50%, making anaerobic digestion an environmentally competitive bioenergy technology.

  6. Mesophilic versus thermophilic anaerobic digestion of cattle manure: methane productivity and microbial ecology.

    Science.gov (United States)

    Moset, Veronica; Poulsen, Morten; Wahid, Radziah; Højberg, Ole; Møller, Henrik Bjarne

    2015-09-01

    In this study, productivity and physicochemical and microbiological (454 sequencing) parameters, as well as environmental criteria, were investigated in anaerobic reactors to contribute to the ongoing debate about the optimal temperature range for treating animal manure, and expand the general knowledge on the relation between microbiological and physicochemical process indicators. For this purpose, two reactor sizes were used (10 m(3) and 16 l), in which two temperature conditions (35°C and 50°C) were tested. In addition, the effect of the hydraulic retention time was evaluated (16 versus 20 days). Thermophilic anaerobic digestion showed higher organic matter degradation (especially fiber), higher pH and higher methane (CH₄) yield, as well as better percentage of ultimate CH₄ yield retrieved and lower residual CH₄ emission, when compared with mesophilic conditions. In addition, lower microbial diversity was found in the thermophilic reactors, especially for Bacteria, where a clear intensification towards Clostridia class members was evident. Independent of temperature, some similarities were found in digestates when comparing with animal manure, including low volatile fatty acids concentrations and a high fraction of Euryarchaeota in the total microbial community, in which members of Methanosarcinales dominated for both temperature conditions; these indicators could be considered a sign of process stability.

  7. Continuous mesophilic anaerobic digestion of manure and rape oilcake - Experimental and modelling study.

    Science.gov (United States)

    Jabłoński, Sławomir J; Biernacki, Piotr; Steinigeweg, Sven; Łukaszewicz, Marcin

    2015-01-01

    Rape oilcake is a by-product formed after the removal of oil from rapeseed. Due to the high content of organic matter rape oilcake seems a good substrate for anaerobic digestion when it cannot be used as fodder. The aim of this work was to optimise the parameters used in a mathematical model of anaerobic digestion for rapeseed oilcake and cattle manure. The composition of these substrates was determined in order to estimate model inputs. Optimised kinetic constants of hydrolysis and decomposition for oilcake (Kdis=0.77, KhydCH=0.55, khydPr=0.57, khydLi=0.30) were estimated based on batch fermentation. The accuracy of the model with improved input parameters was confirmed by continuous fermentation. The average concentration of methane in biogas was about 50%. The biogas production efficiency from organic matter (defined as volatile solids) was 0.42m(3)kg(-1) with an organic substrate loading rate equal to 3.18 kgm(-3)d(-1). The fermentation process demonstrated good stability and efficiency. The accuracy of the optimised model seems sufficient for use in modelling of a full scale process.

  8. 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.

  9. Modeling and simulation of lab-scale anaerobic co-digestion of MEA waste

    Directory of Open Access Journals (Sweden)

    Shuai Wang

    2014-01-01

    Full Text Available Anaerobic digestion model No.1 (ADM1 was applied and expanded in this study to model and simulate anaerobic digestion (AD of an industrial carbon capture reclaimer MEA (monoethanolamine waste (MEAw together with easily degradable organics. The general structure of ADM1 was not changed except for introducing state variables of MEA and complex organics (CO in the waste and biochemical reactions of MEA uptake and CO hydrolysis in the model ADM1_MEAw. Experimental batch test results were used for calibrating kinetics variables. The obtained kinetics were employed in the ADM1_MEAw to simulate semi-continuously fed experimental test for 486 days at room temperature (22 +/- 2oC. The validation results show that the ADM1_MEAw was able to predict the process performance with reasonable accuracy, including process pH, biogas generation and inorganic nitrogen concentrations, for a wide range of feed scenarios. Free ammonia inhibition, was observed to be the main inhibitory effects on acetoclastic methanogenesis, leading to volatile fatty acids (VFA accumulation at high loads. Inhibition assumed to be caused by potentially toxic constituents of MEAw appears to be much less important than ammonia, suggesting that such constituents were broken down by AD.

  10. 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.

  11. Optimal management of substrates in anaerobic co-digestion: An ant colony algorithm approach.

    Science.gov (United States)

    Verdaguer, Marta; Molinos-Senante, María; Poch, Manel

    2016-04-01

    Sewage sludge (SWS) is inevitably produced in urban wastewater treatment plants (WWTPs). The treatment of SWS on site at small WWTPs is not economical; therefore, the SWS is typically transported to an alternative SWS treatment center. There is increased interest in the use of anaerobic digestion (AnD) with co-digestion as an SWS treatment alternative. Although the availability of different co-substrates has been ignored in most of the previous studies, it is an essential issue for the optimization of AnD co-digestion. In a pioneering approach, this paper applies an Ant-Colony-Optimization (ACO) algorithm that maximizes the generation of biogas through AnD co-digestion in order to optimize the discharge of organic waste from different waste sources in real-time. An empirical application is developed based on a virtual case study that involves organic waste from urban WWTPs and agrifood activities. The results illustrate the dominate role of toxicity levels in selecting contributions to the AnD input. The methodology and case study proposed in this paper demonstrate the usefulness of the ACO approach in supporting a decision process that contributes to improving the sustainability of organic waste and SWS management.

  12. 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.

  13. Enhancement of anaerobic digestion efficiency of wastewater sludge and olive waste: Synergistic effect of co-digestion and ultrasonic/microwave sludge pre-treatment.

    Science.gov (United States)

    Alagöz, B Aylin; Yenigün, Orhan; Erdinçler, Ayşen

    2015-12-01

    This study investigates the effect of ultrasonic and microwave pre-treatment on biogas production from the anaerobic co-digestion of olive pomace and wastewater sludges. It was found that co-digestion of wastewater sludge with olive pomace yielded around 0.21 L CH4/g VS added, whereas the maximum methane yields from the mono-digestion of olive pomace and un-pretreated wastewater sludges were 0.18 and 0.16L CH4/g VS added. In the same way, compared to mono-digestion of these substrates, co-digestion increased methane production by 17-31%. The microwave and ultrasonic pre-treatments applied to sludge samples prior to co-digestion process led to further increase in the methane production by 52% and 24%, respectively, compared to co-digestion with un-pretreated wastewater sludge. The highest biogas and methane yields were obtained from the co-digestion of 30 min microwave pre-treated wastewater sludges and olive pomace to be 0.46 L/g VS added and 0.32 L CH4/g VS added, respectively.

  14. Impact of nano zero valent iron (NZVI) on methanogenic activity and population dynamics in anaerobic digestion.

    Science.gov (United States)

    Yang, Yu; Guo, Jialiang; Hu, Zhiqiang

    2013-11-01

    Nano zero valent iron (NZVI), although being increasingly used for environmental remediation, has potential negative impact on methanogenesis in anaerobic digestion. In this study, NZVI (average size = 55 ± 11 nm) showed inhibition of methanogenesis due to its disruption of cell integrity. The inhibition was coincident with the fast hydrogen production and accumulation due to NZVI dissolution under anaerobic conditions. At the concentrations of 1 mM and above, NZVI reduced methane production by more than 20%. At the concentration of 30 mM, NZVI led to a significant increase in soluble COD (an indication of cell disruption) and volatile fatty acids in the mixed liquor along with an accumulation of H2, resulting in a reduction of methane production by 69% (±4% [standard deviation]). By adding a specific methanogenesis inhibitor-sodium 2-bromoethanesulfonate (BES) to the anaerobic sludge containing 30 mM NZVI, the amount of H2 produced was only 79% (±1%) of that with heat-killed sludge, indicating the occurrence of bacterially controlled hydrogen utilization processes. Quantitative PCR data was in accordance with the result of methanogenesis inhibition, as the level of methanogenic population (dominated by Methanosaeta) in the presence of 30 mM NZVI decreased significantly compared to that of the control. On the contrary, ZVI powder (average size inhibited methanogenesis described herein, the results suggest that the rapid hydrogen production due to NZVI dissolution also contribute to methanogenesis inhibition and lead to bacterially controlled hydrogenotrophic processes.

  15. AMMONIA INHIBITION IN THERMOPHILIC ANAEROBIC DIGESTION OF DAIRY CATTLE MANURE

    Directory of Open Access Journals (Sweden)

    S. Sutaryo

    2015-04-01

    Full Text Available This study investigated the effect of five different concentrations of total ammonia nitrogen (TANand free ammonia (FA on the methane yield and digester performance under thermophilic conditions(50°C. Five identical continuously fed digesters were used. The experiment was run for four timeshydraulic retention time (HRT. Data were statitically analysed using the data Analysis Tool Packavailable with the Microsoft Excel program. Different ammonia levels were obtained by pulsing urea toobtain the target level of TAN and FA, and to subsequently maintaining the concentration of ammonialevels by daily urea additions. The result showed a strong negative correlation between both TAN andFA concentrations and methane yield. The methane yield was reduced by 24, 30, 52 and 66% indigesters that had TAN levels of 2.9, 3.6, 4.4 and 5.1 g/L, respectively, corresponding to 0.7, 1.1,1.5 and1.8 g/L FA. Total volatile fatty acid and especially isovaleric and isobutyric acid concentrations wereelevated during ammonia inhibition. Concentration of TAN in the biogas digester exceeding 3 g/Lindicating that very often the full biogas potential is not achieved due to ammonia inhibition and thatlonger HRT should be used to compensate or a lower process temperature should be chosen.

  16. Computer-aided design model for anaerobic-phased-solids digester system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.; Zhang, R. [University of California, Davis, CA (United States); Tiangco, V. [California Energy Commission, Sacramento, CA (United States)

    1999-07-01

    The anaerobic-phased-solids (APS) digester system is a newly developed anaerobic digestion system for converting solid wastes, such as crop residues and food wastes, into biogas for power and heat generation. A computer-aided engineering design model has been developed to design the APS-digester system and study the heat transfer from the reactors and energy production of the system. Simulation results of a case study are presented by using the model to predict the heating energy requirement and biogas energy production for anaerobic digestion of garlic waste. The important factors, such as environmental conditions, insulation properties, and characteristics of the wastes, on net energy production are also investigated. (author)

  17. Pb(II) biosorption using anaerobically digested sludge.

    Science.gov (United States)

    Tokcaer, Emre; Yetis, Ulku

    2006-10-11

    Removal of Pb(II) by using resting cells of anaerobically digested sludge (ADS) obtained from a nearby wastewater treatment plant was examined. Firstly, sorption kinetic and equilibrium experiments were conducted using agitated, thermostated (25 degrees C) batch reactors. The maximum Pb(II) sorption capacity was found to be very high (1,750 mg/g dry ADS or 8.45 mmol/g dry ADS). At all initial Pb(II) concentrations tested, sorption resulted in neutralization with an increase in the solution pH from an initial value of 4.0-5.5 to an equilibrium value of 7.0-8.0, at which Pb(II) can precipitate as hydroxide. The removal of Pb(II) by ADS was found to involve bioprecipitation as well as biosorption. FTIR spectrometry highlighted carboxyl groups present on the surface of ADS as the major functional groups responsible for biosorption. Secondly, a three-stage semi-continuous pseudo-counter current reactor system was tested to reduce ADS requirement in comparison to a conventional single-stage batch reactor. At an initial Pb(II) concentration of about 200 mg/L, an effluent Pb(II) concentration of 1.3 mg/L was achieved in the three stage reactor, corresponding to a metal removal capacity of 682.7 mg/g dry ADS (3.30 mmol/g), in comparison to 1.9 mg/L and 644.0 mg/g dry ADS (3.10 mmol/g) for the single-stage batch reactor.

  18. One- and two-phase anaerobic digestion of ley crop silage with and without liquid recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Nordberg, Aa.

    1996-10-01

    In this study the effects of liquid recirculation on hydrolysis and methanogenesis in one- and two-phase biogas processes were investigated in comparison with water-diluted processes. The operation of a water-diluted one-phase process resulted in process imbalances at a low loading rate. In a water-diluted two-phase process the fibre degrading capability was lost. The reason for the poor process performance was due to a deficiency in trace elements, since the supplementation of cobalt resulted in an increased conversion rate of acetate. The recirculation of process liquid resulted in an accumulation of different compounds which initially stabilized one-phase processes and stimulated the hydrolysis and the methane production in the liquefaction-acidogenesis stage of a two-phase process. However, upon continuous recirculation the concentration of free ammonia reached toxic levels, which resulted in a decrease in the methane yield both in the methanogenic reactor of the two-phase process and in the one-phase process. Due to the decreased methane production, acids started to accumulate which subsequently inhibited the hydrolysis in the one-phase process. The systematic variation in the processes were evaluated using principal component analysis and principal component regression. The interpretation of the dynamic behaviour of the processes was facilitated by the use of score plots and loading plots. The results indicate that ley crops do not meet the nutrient requirements of the bacteria in anaerobic digestion. Thus, the low content of trace elements and the high content of protein which subsequently will cause toxic levels of ammonia in digesting system with low water consumption, suggests co-digestion with supplementary feedstocks. 95 refs, 5 figs, 3 tabs