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Sample records for demand cod removal

  1. An integrated mathematical model for chemical oxygen demand (COD) removal in moving bed biofilm reactors (MBBR) including predation and hydrolysis.

    Science.gov (United States)

    Revilla, Marta; Galán, Berta; Viguri, Javier R

    2016-07-01

    An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions.

  2. Effects of chemical oxygen demand (COD)/N ratios on pollutants removal in the subsurface wastewater infiltration systems with/without intermittent aeration.

    Science.gov (United States)

    Song, Siyu; Pan, Jing; Wu, Shiwei; Guo, Yijing; Yu, Jingxiao; Shan, Qingchi

    2016-01-01

    The matrix oxidation reduction potential level, organic pollutants and nitrogen removal performances of eight subsurface wastewater infiltration systems (SWISs) (four with intermittent aeration, four without intermittent aeration) fed with influent chemical oxygen demand (COD)/N ratio of 3, 6, 12 and 18 were investigated. Nitrification of non-aerated SWISs was poor due to oxygen deficiency while higher COD/N ratios further led to lower COD and nitrogen removal rate. Intermittent aeration achieved almost complete nitrification, which successfully created aerobic conditions in the depth of 50 cm and did not change anoxic or anaerobic conditions in the depth of 80 and 110 cm. The sufficient carbon source in high COD/N ratio influent greatly promoted denitrification in SWISs with intermittent aeration. High average removal rates of COD (95.68%), ammonia nitrogen (NH4(+)-N) (99.32%) and total nitrogen (TN) (89.65%) were obtained with influent COD/N ratio of 12 in aerated SWISs. The results suggest that intermittent aeration was a reliable option to achieve high nitrogen removal in SWISs, especially with high COD/N ratio wastewater.

  3. Photocatalysis applied in the studies of decolorization and COD removal of landfill leachate

    Directory of Open Access Journals (Sweden)

    Gisselma Batista

    2014-10-01

    Full Text Available In this paper photocatalysis processes on titanium dioxide suspension in aqueous solution illuminated with UV light are described for decolorization and Chemical Oxygen Demand (COD removal of landfill leachate. Several operational parameters to achieve optimum efficiency are presented. The properties of the decolorization and COD removal were enhanced and studied by spectrophotometer methods. The results indicate that the process can be used as a pretreatment to the conventional processes.

  4. Tendu leaves refuse as a Biosorbent for COD removal from ...

    African Journals Online (AJOL)

    Bioline

    industry, is effective biosorbent for the removal of COD; offering a cheap option for primary treatment of the effluent. ... Among these are both chemical and biological treatments such as ..... of water and waste water, 17th edition, (APHA.

  5. Removal of hard COD, nitrogenous compounds and phenols from a ...

    African Journals Online (AJOL)

    2015-07-04

    Jul 4, 2015 ... of phenols, COD and nitrogenous compounds in the wastewater. Keywords: ammonia ... Biological treatment has been widely used only to treat the ..... MOLVA M (2004) Removal of phenol from industrial wastewa- ters using ...

  6. COD removal characteristics in air-cathode microbial fuel cells

    KAUST Repository

    Zhang, Xiaoyuan

    2015-01-01

    © 2014 Elsevier Ltd. Exoelectrogenic microorganisms in microbial fuel cells (MFCs) compete with other microorganisms for substrate. In order to understand how this affects removal rates, current generation, and coulombic efficiencies (CEs), substrate removal rates were compared in MFCs fed a single, readily biodegradable compound (acetate) or domestic wastewater (WW). Removal rates based on initial test conditions fit first-order kinetics, but rate constants varied with circuit resistance. With filtered WW (100Ω), the rate constant was 0.18h- 1, which was higher than acetate or filtered WW with an open circuit (0.10h- 1), but CEs were much lower (15-24%) than acetate. With raw WW (100Ω), COD removal proceeded in two stages: a fast removal stage with high current production, followed by a slower removal with little current. While using MFCs increased COD removal rate due to current generation, secondary processes will be needed to reduce COD to levels suitable for discharge.

  7. COD Removal Efficiencies of Some Aromatic Compounds in Supercritical Water Oxidation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Some aromatic compounds, phenol, aniline and nitrobenzene, were oxidized in supercritical water. It was experimentally found that the chemical oxygen demand (COD) removal efficiency of these organic compounds can achieve a high level more than 90% in a short residence time at temperatures high enough. As temperature, pressure and residence time increase, the COD removal efficiencies of the organic compounds would all increase. It is also found that temperature and residence time offer greater influences on the oxidation process than pressure. The difficulty in oxidizing these three compounds is in the order of nitrobenzene > aniline > Phenol. In addition, it is extremely difficult to oxidize aniline and nitrobenzene to CO2 and H2O at the temperature lower than 873.15 K and 923.15 K, respectively. Only at the temperature higher than 873.15 K and 923.15 K, respectively, the COD removal efficiencies of 90% of aniline and nitrobenzene can be achieved.

  8. Removal of COD from laundry wastewater by electrocoagulation/electroflotation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-T. [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, Tainan County, Hsien 717, Taiwan (China)], E-mail: ctwwang@mail.hwai.edu.tw; Chou, W.-L. [Department of Safety Health and Environmental Engineering and Institute of Occupational Safety and Hazard Prevention, HungKuang University, Sha-Lu, Taichung 433, Taiwan (China); Kuo, Y.-M. [Department of Safety Health and Environmental Engineering, Chung Hwa University of Medical Technology, Tainan County, Hsien 717, Taiwan (China)

    2009-05-15

    The removal efficiency of COD in the treatment of simulated laundry wastewater using electrocoagulation/electroflotation technology is described. The experimental results showed that the removal efficiency was better, reaching to about 62%, when applying ultrasound to the electrocoagulation cell. The solution pH approached neutrality in all experimental runs. The optimal removal efficiency of COD was obtained by using the applied voltage of 5 V when considering the energy efficiency and the acceptable removal efficiency simultaneously. The Cl{sup -} concentration of less than 2500 ppm had a positive effect on the removal efficiency. The performance of the monopolar connection of electrodes was better than that of the bipolar connection in this work. In addition, the removal efficiency of using Al electrodes was higher in comparison with using Fe electrodes in the study. The highest COD removal amount per joule was found to be 999 mg dm{sup -3} kW h{sup -1} while using two Al electrodes, although the removal efficiency increased with the number of Al plates.

  9. COD and color removal of reactive orange 16 dye solution by electrochemical oxidation and adsorption method

    Science.gov (United States)

    Zakaria, Zuhailie; Ahmad, Wan Yaacob Wan; Yusop, Muhammad Rahimi; Othman, Mohamed Rozali

    2015-09-01

    Degradation of Reactive Orange 16 (RO16) dye was investigated using electrochemical oxidation and adsorption (batch method) using mixture of coconut trunk charcoal-graphite-tin-polyvinyl chloride(PVC). In batch studies for adsorbents pellet and powder form of the charcoal mixture were used. RO16 was chosen as the model dye because of its high resistance towards conventional treatment methods. NaCl and RO16 concentration, treatment duration, weight of electrode and adsorbent and volume of solution were kept constant for both methods. The effectiveness of the treatments were compared and evaluated by percentage of RO16 decolorization and chemical oxygen demand (COD) removal and results indicated that electrochemical oxidation method ables to decolorized RO16 dye up to 98.5% after 20 minutes electrolysis time while pellet and powder in batch method only removed 17.1 and 33.6% of RO16 color respectively. However, only 45.6% of COD can be removed using electrochemical oxidation method while pellet and powder in batch method removed 47.8 and 49.6% of COD respectively. The decolorization and COD removal of RO16 was determined using UV-Vis spectrophotometer (by the changes of absorption spectrum intensity of azo chromophore (-N=N-) at λ=388 and 492.50 nm and Hach spectrophotometer respectively. FTIR was used to determine functional groups present in the coconut trunk charcoal.

  10. Factorial design analysis for COD removal from landfill leachate by photoassisted Fered-Fenton process.

    Science.gov (United States)

    Wu, Xiaogang; Zhang, Hui; Li, Yanli; Zhang, Daobin; Li, Xianwang

    2014-01-01

    The Fered-Fenton process has been shown to be an effective method for leachate treatment, but it still faces problems of inadequate regeneration of ferrous ion. However, the use of the photoassisted Fered-Fenton process could overcome this difficulty and improve the efficiency of chemical oxygen demand (COD) removal since photoassisted Fered-Fenton process induces the production of hydroxyl radicals from the regeneration of ferrous ions and the reaction of hydrogen peroxide with UV light. As there are so many operating parameters in photoassisted Fered-Fenton process, it is necessary to develop a mathematical model in order to produce the most economical process. In the present study, a factorial design was carried out to evaluate leachate treatment by photoassisted Fered-Fenton process. The influence of the following variables: H₂O₂ concentration, Fe(2+) concentration, current density, and initial pH in the photoassisted Fered-Fenton process was investigated by measuring COD removal efficiencies after 60-min reaction. The relationship between COD removal and the most significant independent variables was established by means of an experimental design. The H₂O₂ concentration, Fe(2+) concentration, initial pH, and the interaction effect between current density and initial pH were all significant factors. The factorial design models were derived based on the COD removal efficiency results and the models fit the data well.

  11. [Effects of COD/TN and HRT(s) on nutrients removal by an alternating anoxic/oxic CAST].

    Science.gov (United States)

    Wang, Li; Peng, Yong-Zhen; Ma, Juan; Liu, Yang; Ma, Ning-Ping

    2010-10-01

    The effects of different COD/TN and HRT(s) (hydraulic retention time of select) on nutrients removal were investigated by using an alternating anoxic/oxic CAST (cyclic activated sludge technology) fed with municipal wastewater. The results showed that various COD/TN and HRT(s) had a bigger influence on the nitrogen removal efficiency rather than the COD removal efficiency. As the influent C/N ratios were about 2.6 and 3.5, ammonia was removed by 98% and TN removal efficiency was increased from 62.9% to 76.2% and 72.1% to 84.6%, respectively, by increasing the HRT(s) from 1.8 h to 5 h. When the COD/TN ratio was increased to about 4.4, TN removal efficiency was decreased from 86.3% to 58.2% by enlarging the HRT(s), which was due to the incomplete nitrification of ammonia. It was also observed that both of increasing the COD/TN and HRT(s) could improve the phosphorus removal performance of the system. Furthermore, effluent of CAST reached the demanded A of integrated wastewater discharge standards (GB 18918-2002) when the COD/TN and HRT(s) were 4.4 and 1.8 h, respectively.

  12. Nitrogen and COD removal from domestic and synthetic wastewater in subsurface-flow constructed wetlands.

    Science.gov (United States)

    Collison, R S; Grismer, M E

    2013-09-01

    Comparisons of the performance of constructed-wetland systems (CWs) for treating domestic wastewater in the laboratory and field may use pathogen-free synthetic wastewater to avoid regulatory health concerns. However, little to no data are available describing the relative treatment efficiencies of CWs to both actual and synthetic domestic wastewaters so as to enable such comparison. To fill this gap, treatment performances with respect to organics (chemical organic demand; COD) and nitrogen (ammonium and nitrate) removal from domestic (septic tank) and a similar-strength synthetic wastewater under planted and non-planted subsurface-flow CWs are determined. One pair of CWs was planted with cattails in May 2008, whereas the adjacent system was non-planted. Collected septic tank or synthesized wastewater was allowed to gravity feed each CWs, and effluent samples were collected and tested for COD and nitrogen species regularly during four different periods over six months. Overall, statistically significant greater removal of COD (-12%) and nitrogen (-5%) occurred from the synthetic as compared with the domestic wastewater from the planted and non-planted CWs. Effluent BOD5/COD ratios from the synthetic wastewater CWs averaged nearly twice that from the domestic wastewater CWs (0.17 vs 0.10), reflecting greater concentrations of readily degraded compounds. That removal fractions were consistent across the mid-range loading rates to the CWs suggests that the synthetic wastewater can be used in testing laboratory CWs with reasonable success in application of their results to the field.

  13. Simultaneous removal of COD and nitrogen using a novel carbon-membrane aerated biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A membrane aerated biofilm reactor is a promising technology for wastewater treatment. In this study, a carbon-membrane aerated biofilm reactor (CMABR) has been developed, to remove carbon organics and nitrogen simultaneously from one reactor. The results showed that CMABR has a high chemical oxygen demand (COD) and nitrogen removal efficiency, as it is operated with a hydraulic retention time (HRT) of 20 h, and it also showed a perfect performance, even if the HRT was shortened to 12 h. In this period, the removal efficiencies of COD, ammonia nitrogen (NH4+-N), and total nitrogen (TN) reached 86%, 94%, and 84%, respectively. However,the removal efficiencies of NH4+-N and TN declined rapidly as the HRT was shortened to 8 h. This is because of the excessive growth of biomass on the nonwoven fiber and very high organic loading rate. The fluorescence in situ hybridization (FISH) analysis indicated that the ammonia oxidizing bacteria (AOB) were mainly distributed in the inner layer of the biofilm. The coexistence of AOB and eubacteria in one biofilm can enhance the simultaneous removal of COD and nitrogen.

  14. Removal of colour and COD from synthetic textile wastewaters using O3, PAC, H2O2 and HCO3-.

    Science.gov (United States)

    Oguz, Ensar; Keskinler, Bülent

    2008-03-01

    This study aimed to investigate removal of colour and chemical oxygen demand (COD) from synthetic textile wastewaters using O3, powder activated carbon (PAC), H2O2 and HCO3- in a semi-batch reactor. 1:2 metal complex dyestuffs containing two molecules of dyestuffs versus a chromium atom was used. Experiments were conducted under the various pHs (3-12), temperatures (18-70 degrees C), ozone doses (164-493 mg min(-1)). The combined effect of substances used on the removal of colour and COD was investigated. The mechanisms of colour and COD removal on the PAC were explained on the basis of the results of Fourier transform infrared spectroscopy (FTIR). In addition, the zeta potential values of PAC, ozonated PAC and ozonated PAC contaminated with intermediates were determined. The zeta potential values and FTIR plots of PAC particulates showed that PAC acted as an adsorbent in the combined processes. It was thought that all of the substances used in the semi-batch reactor had the combined effect on the removal of colour and COD because of the short treatment time of 5 min and high efficiencies of the removal of colour and COD. The efficiencies of removal of colour and COD in combination were compared with adsorption and ozonation only. In this study, the efficiencies of colour and COD removal during a reaction time of 30 min were obtained as 99 and 95%, respectively. At the result of this study, it was concluded that O3, PAC and H2O2 were an important substances for the removal of colour and COD from synthetic textile wastewater when they were used in combination.

  15. Preparation of Bamboo Chars and Bamboo Activated Carbons to Remove Color and COD from Ink Wastewater.

    Science.gov (United States)

    Hata, Motohide; Amano, Yoshimasa; Thiravetyan, Paitip; Machida, Motoi

    2016-01-01

    Bamboo chars and bamboo activated carbons prepared by steam activation were applied for ink wastewater treatment. Bamboo char at 800 °C was the best for the removal of color and chemical oxygen demand (COD) from ink wastewater compared to bamboo chars at 300 to 700 °C due to higher surface area and mesopore volume. Bamboo activated carbon at 600 °C (S600) was the best compared to bamboo activated carbon at 800 °C (S800), although S800 had larger surface area (1108 m(2)/g) than S600 (734 m(2)/g). S600 had higher mesopore volume (0.20 cm(3)/g) than S800 (0.16 cm(3)/g) and therefore achieved higher color and COD removal. All bamboo activated carbons showed higher color and COD removal efficiency than commercial activated carbon. In addition, S600 had the superior adsorption capacity for methylene blue (0.89 mmol/g). Therefore, bamboo is a suitable material to prepare adsorbents for removal of organic pollutants.

  16. Comparison of COD removal from pharmaceutical wastewater by electrocoagulation, photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes.

    Science.gov (United States)

    Farhadi, Sajjad; Aminzadeh, Behnoush; Torabian, Ali; Khatibikamal, Vahid; Alizadeh Fard, Mohammad

    2012-06-15

    This work makes a comparison between electrocoagulation (EC), photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes to investigate the removal of chemical oxygen demand (COD) from pharmaceutical wastewater. The effects of operational parameters such as initial pH, current density, applied voltage, amount of hydrogen peroxide and electrolysis time on COD removal efficiency were investigated and the optimum operating range for each of these operating variables was experimentally determined. In electrocoagulation process, the optimum values of pH and voltage were determined to be 7 and 40 V, respectively. Desired pH and hydrogen peroxide concentration in the Fenton-based processes were found to be 3 and 300 mg/L, respectively. The amounts of COD, pH, electrical conductivity, temperature and total dissolved solids (TDS) were on-line monitored. Results indicated that under the optimum operating range for each process, the COD removal efficiency was in order of peroxi-electrocoagulation > peroxi-photoelectrocoagulation > photoelectrocoagulation>electrocoagulation. Finally, a kinetic study was carried out using the linear pseudo-second-order model and results showed that the pseudo-second-order equation provided the best correlation for the COD removal rate.

  17. Performance of an electrochemical COD (chemical oxygen demand) sensor with an electrode-surface grinding unit.

    Science.gov (United States)

    Geun Jeong, Bong; Min Yoon, Seok; Ho Choi, Chang; Koang Kwon, Kil; Sik Hyun, Moon; Heui Yi, Dong; Soo Park, Hyung; Kim, Mia; Joo Kim, Hyung

    2007-12-01

    An electrochemical COD (chemical oxygen demand) sensor using an electrode-surface grinding unit was investigated. The electrolyzing (oxidizing) action of copper on an organic species was used as the basis of the COD measuring sensor. Using a simple three-electrode cell and a surface grinding unit, the organic species is activated by the catalytic action of copper and oxidized at a working electrode, poised at a positive potential. When synthetic wastewater was fed into the system, the measured Coulombic yields were found to be dependent on the COD of the synthetic wastewater. A linear correlation between the Coulombic yields and the COD of the synthetic wastewater was established (10-1000 mg L(-1)) when the electrode-surface grinding procedure was activated briefly at 8 h intervals. When various kinds of wastewater samples obtained from various sewage treatment plants were measured, linear correlations (r(2)> or = 0.92) between the measured EOD (electrochemical oxygen demand) value and COD of the samples were observed. At a practical wastewater treatment plant, the measurement system was successfully operated with high accuracy and good stability over 3 months. These experimental results show that the application of the measurement system would be a rapid and practical method for the determination of COD in water industries.

  18. Comparison of coagulation, ozone and ferrate treatment processes for color, COD and toxicity removal from complex textile wastewater.

    Science.gov (United States)

    Malik, Sameena N; Ghosh, Prakash C; Vaidya, Atul N; Waindeskar, Vishal; Das, Sera; Mudliar, Sandeep N

    2017-09-01

    In this study, the comparative performance of coagulation, ozone, coagulation + ozone + coagulation and potassium ferrate processes to remove chemical oxygen demand (COD), color, and toxicity from a highly polluted textile wastewater were evaluated. Experimental results showed that ferrate alone had no effect on COD, color and toxicity removal. Whereas, in combination with FeSO4, it has shown the highest removal efficiency of 96.5%, 83% and 75% for respective parameters at the optimal dose of 40 mgL(-1) + 3 ml FeSO4 (1 M) in comparison with other processes. A seed germination test using seeds of Spinach (Spinacia oleracea) also indicated that ferrate was more effective in removing toxicity from contaminated textile wastewater. Potassium ferrate also produces less sludge with maximum contaminant removal, thereby making the process more economically feasible. Fourier transform infrared spectroscopy (FTIR) analysis also shows the cleavage of the chromophore group and degradation of textile wastewater during chemical and oxidation treatment processes.

  19. Mathematical modeling of copper(II) ion inhibition on COD removal in an activated sludge unit.

    Science.gov (United States)

    Pamukoglu, M Yunus; Kargi, Fikret

    2007-07-19

    A mathematical model was developed to describe the Cu(II) ion inhibition on chemical oxygen demand (COD) removal from synthetic wastewater containing 15 mg l(-1) Cu(II) in an activated sludge unit. Experimental data obtained at different sludge ages (5-30 days) and hydraulic residence times (HRT) (5-25 h) were used to determine the kinetic, stoichiometric and inhibition constants for the COD removal rate in the presence and absence of Cu(II) ions. The inhibition pattern was identified as non-competitive, since Cu(II) ion inhibitions were observed both on maximum specific substrate removal rate (k) and on the saturation constant (Ks) with the inhibition constants of 97 and 18 mg l(-1), respectively, indicating more pronounced inhibition on Ks. The growth yield coefficient (Y) decreased and the death rate constant (b) increased in the presence of Cu(II) ions due to copper ion toxicity on microbial growth with inhibition constants of 29 and 200 mg l(-1), respectively indicating more effective inhibition on the growth yield coefficient or higher maintenance requirements. The mathematical model with the predetermined kinetic constants was able to predict the system performance reasonably well especially at high HRT operations.

  20. Nitrate and COD removal in an upflow biofilter under an aerobic atmosphere.

    Science.gov (United States)

    Ji, Bin; Wang, Hongyu; Yang, Kai

    2014-04-01

    A continuous-upflow submerged biofilter packed with ceramsite was constructed for nitrate removal under an aerobic atmosphere. Pseudomonas stutzeri X31, an aerobic denitrifier isolate, was added to the bioreactor as an inoculum. The influent NO3(-)-N concentrations were 63.0-73.8 mg L(-1). The best results were achieved when dissolved oxygen level was 4.6 mg L(-1) and C/N ratio was 4.5. The maximum removal efficiencies of carbon oxygen demand (COD) and NO3(-)-N were 94.04% and 98.48%, respectively at 30°C, when the hydraulic load was 0.75 m h(-1). The top section of the bioreactor possessed less biofilm but higher COD and NO3(-)-N removal rates than the bottom section. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) technique combined with electron microscopic examination indicated P. stutzeri X31 and Paracoccus versutus were the most dominant bacteria. Amoeba sp., Vorticella sp., Philodina sp., and Stephanodiscus sp. were also found in the bioreactor.

  1. A novel approach for phosphorus recovery and no wasted sludge in enhanced biological phosphorus removal process with external COD addition.

    Science.gov (United States)

    Xia, Cheng-Wang; Ma, Yun-Jie; Zhang, Fang; Lu, Yong-Ze; Zeng, Raymond J

    2014-01-01

    In enhanced biological phosphorus removal (EBPR) process, phosphorus (P) in wastewater is removed via wasted sludge without actual recovery. A novel approach to realize phosphorus recovery with special external chemical oxygen demand (COD) addition in EBPR process was proposed. During the new operating approach period, it was found that (1) no phosphorus was detected in the effluent; (2) with an external addition of 10 % of influent COD amount, 79 % phosphorus in the wastewater influent was recovered; (3) without wasted sludge, the MLVSS concentration in the system increased from 2,010 to 3,400 mg/L and kept stable after day 11 during 24-day operating period. This demonstrates that the novel approach is feasible to realize phosphorus recovery with no wasted sludge discharge in EBPR process. Furthermore, this approach decouples P removal and sludge age, which may enhance the application of membrane bioreactor for P removal.

  2. Comparison of COD removal from pharmaceutical wastewater by electrocoagulation, photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes

    Energy Technology Data Exchange (ETDEWEB)

    Farhadi, Sajjad, E-mail: sajjadfarhadi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran (Iran, Islamic Republic of); Aminzadeh, Behnoush, E-mail: bamin@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran (Iran, Islamic Republic of); Torabian, Ali, E-mail: atorabi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran (Iran, Islamic Republic of); Khatibikamal, Vahid, E-mail: vahidkhatibi@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran (Iran, Islamic Republic of); Alizadeh Fard, Mohammad, E-mail: malizadeh1987@ut.ac.ir [Department of Civil and Environmental Engineering, Graduate Faculty of Environment, University of Tehran (Iran, Islamic Republic of)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Hydrogen peroxide improves the performance of electrocoagulation process. Black-Right-Pointing-Pointer UV light can be effective on the performance on peroxi-electrocoagulation and electrocoagulation processes. Black-Right-Pointing-Pointer The optimal amount of hydrogen peroxide for peroxi-electrocoagulation process for COD removal from pharmaceutical wastewater is 300 mg/L. Black-Right-Pointing-Pointer The optimal values of pH for electrocoagulation and peroxi-electrocoagulation are 7 and 3, respectively. - Abstract: This work makes a comparison between electrocoagulation (EC), photoelectrocoagulation, peroxi-electrocoagulation and peroxi-photoelectrocoagulation processes to investigate the removal of chemical oxygen demand (COD) from pharmaceutical wastewater. The effects of operational parameters such as initial pH, current density, applied voltage, amount of hydrogen peroxide and electrolysis time on COD removal efficiency were investigated and the optimum operating range for each of these operating variables was experimentally determined. In electrocoagulation process, the optimum values of pH and voltage were determined to be 7 and 40 V, respectively. Desired pH and hydrogen peroxide concentration in the Fenton-based processes were found to be 3 and 300 mg/L, respectively. The amounts of COD, pH, electrical conductivity, temperature and total dissolved solids (TDS) were on-line monitored. Results indicated that under the optimum operating range for each process, the COD removal efficiency was in order of peroxi-electrocoagulation > peroxi-photoelectrocoagulation > photoelectrocoagulation > electrocoagulation. Finally, a kinetic study was carried out using the linear pseudo-second-order model and results showed that the pseudo-second-order equation provided the best correlation for the COD removal rate.

  3. Performance of COD removal from acid scarlet BS-containing solution in a novel packed-bed hollow-tube photocatalytic (PHP) reactor.

    Science.gov (United States)

    Xiong, Ya; He, Chun; An, Taicheng; Yu, Quan; Zha, Changhong; Zhu, Xihai

    2003-05-01

    A novel packed-bed hollow-tube photocatalytic (PHP) reactor using TiO2-coated Ti particles as fillers was designed and applied to treat a simulated dye wastewater containing Acid Scarlet BS. The experimental results showed that PHP reactor could efficiently remove chemical oxygen demand (COD) from the dye solution and the COD removal efficiency was considerably dependent on the operating parameters, airflow, initial dye concentration and initial pH value of solution. It was also found that the inserting of the hollow tubes could apparently increase the COD removal efficiency of the packed-bed photo-reactor while the application of external electric field could improve the degradation efficiency of the dye but not obviously promote COD removal.

  4. Removal of Sulfide and COD from a Crude Oil Wastewater Model by Aluminum and Iron Electrocoagulation

    Directory of Open Access Journals (Sweden)

    K. I. Dermentzis

    2016-04-01

    Full Text Available The treatment of petroleum wastewater was studied using the electrocoagulation process with aluminum and iron electrodes aiming to simultaneous removal of sulfide and COD. All affecting parameters, such as solution pH, applied current density, time of electroprocessing, electrode material and addition of surfactant, were investigated. Sulfide was rapidly and effectively removed using iron electrodes. The removal of COD was effectively effectively enhanced by performing the electrocoagulation process after addition of the surfactant polyethylene glycol oleate.

  5. Removal of Sulfide and COD from a Crude Oil Wastewater Model by Aluminum and Iron Electrocoagulation

    OpenAIRE

    K. I. Dermentzis

    2016-01-01

    The treatment of petroleum wastewater was studied using the electrocoagulation process with aluminum and iron electrodes aiming to simultaneous removal of sulfide and COD. All affecting parameters, such as solution pH, applied current density, time of electroprocessing, electrode material and addition of surfactant, were investigated. Sulfide was rapidly and effectively removed using iron electrodes. The removal of COD was effectively effectively enhanced by performing the electrocoagulation ...

  6. Improvement of COD and color removal from UASB treated poultry manure wastewater using Fenton's oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Yetilmezsoy, Kaan [Department of Environmental Engineering, Yildiz Technical University, 34349 Yildiz, Besiktas, Istanbul (Turkey)], E-mail: yetilmez@yildiz.edu.tr; Sakar, Suleyman [Department of Environmental Engineering, Yildiz Technical University, 34349 Yildiz, Besiktas, Istanbul (Turkey)

    2008-03-01

    The applicability of Fenton's oxidation as an advanced treatment for chemical oxygen demand (COD) and color removal from anaerobically treated poultry manure wastewater was investigated. The raw poultry manure wastewater, having a pH of 7.30 ({+-}0.2) and a total COD of 12,100 ({+-}910) mg/L was first treated in a 15.7 L of pilot-scale up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated for 72 days at mesophilic conditions (32 {+-} 2 deg. C) in a temperature-controlled environment with three different hydraulic retention times (HRT) of 15.7, 12 and 8.0 days, and with organic loading rates (OLR) between 0.650 and 1.783 kg COD/(m{sup 3} day). Under 8.0 days of HRT, the UASB process showed a remarkable performance on total COD removal with a treatment efficiency of 90.7% at the day of 63. The anaerobically treated poultry manure wastewater was further treated by Fenton's oxidation process using Fe{sup 2+} and H{sub 2}O{sub 2} solutions. Batch tests were conducted on the UASB effluent samples to determine the optimum operating conditions including initial pH, effects of H{sub 2}O{sub 2} and Fe{sup 2+} dosages, and the ratio of H{sub 2}O{sub 2}/Fe{sup 2+}. Preliminary tests conducted with the dosages of 100 mg Fe{sup 2+}/L and 200 mg H{sub 2}O{sub 2}/L showed that optimal initial pH was 3.0 for both COD and color removal from the UASB effluent. On the basis of preliminary test results, effects of increasing dosages of Fe{sup 2+} and H{sub 2}O{sub 2} were investigated. Under the condition of 400 mg Fe{sup 2+}/L and 200 mg H{sub 2}O{sub 2}/L, removal efficiencies of residual COD and color were 88.7% and 80.9%, respectively. Under the subsequent condition of 100 mg Fe{sup 2+}/L and 1200 mg H{sub 2}O{sub 2}/L, 95% of residual COD and 95.7% of residual color were removed from the UASB effluent. Results of this experimental study obviously indicated that nearly 99.3% of COD of raw poultry manure wastewater could be effectively removed by a

  7. Removal of turbidity, COD and BOD from secondarily treated sewage water by electrolytic treatment

    Science.gov (United States)

    Chopra, Ashok Kumar; Sharma, Arun Kumar

    2013-03-01

    A preliminary study was conducted for the removal of turbidity (TD), chemical oxygen demand (COD) and biochemical oxygen demand (BOD) from secondarily treated sewage (STS) water through the electrolytic batch mode experiments with DC power supply (12 V) up to 30 min and using a novel concept of electrode combinations of different metals. The different surface areas (40, 80, 120 and 160 cm2) of the electrodes as a function of cross-sectional area of the reactor and the effect of inter-electrode distances (2.5-10 cm) on the electrolysis of STS water were studied. This study revealed that the effluent can be effectively treated with the aluminum (Al) and iron (Fe) electrode combinations (Al-Fe and Fe-Al). The maximum removal of TD (81.51 %), COD (74.36 %) and BOD (70.86 %) was recorded with Al-Fe electrode system, while the removal of these parameters was found to be 71.11, 64.95 and 61.87 %, respectively, with Fe-Al electrode combination. The Al-Fe electrode combination had lower electrical energy consumption (2.29 kWh/m3) as compared to Fe-Al electrode combination (2.50 kWh/m3). The economic evaluation of electrodes showed that Al-Fe electrode combination was better than Fe-Al electrode combination. This revealed the superiority of aluminum as a sacrificial electrode over that of iron which can probably be attributed to better flocculation capabilities of aluminum than that of iron.

  8. An experimental model of COD abatement in MBBR based on biofilm growth dynamic and on substrates' removal kinetics.

    Science.gov (United States)

    Siciliano, Alessio; De Rosa, Salvatore

    2016-08-01

    In this study, the performance of a lab-scale Moving Bed Biofilm Reactor (MBBR) under different operating conditions was analysed. Moreover, the dependence of the reaction rates both from the concentration and biodegradability of substrates and from the biofilm surface density, by means of several batch kinetic tests, was investigated. The reactor controls exhibited an increasing COD (Chemical Oxygen Demand) removal, reaching maximum yields (close to 90%) for influent loadings of up to12.5 gCOD/m(2)d. From this value, the pilot plant performance decreased to yields of only about 55% for influent loadings greater than 16 gCOD/m(2)d. In response to the influent loading increase, the biofilm surface density exhibited a logistic growing trend until reaching a maximum amount of total attached solids of about 9.5 g/m(2). The kinetic test results indicated that the COD removal rates for rapidly biodegradable, rapidly hydrolysable and slowly biodegradable substrates were not affected by the organic matter concentrations. Instead, first-order kinetics were detected with respect to biofilm surface density. The experimental results permitted the formulation of a mathematical model to predict the MBBR organic matter removal efficiency. The validity of the model was successfully tested in the lab-scale plant.

  9. Characterization of the COD removal, electricity generation, and bacterial communities in microbial fuel cells treating molasses wastewater.

    Science.gov (United States)

    Lee, Yun-Yeong; Kim, Tae G; Cho, Kyung-Suk

    2016-11-09

    The chemical oxygen demand (COD) removal, electricity generation, and microbial communities were compared in 3 types of microbial fuel cells (MFCs) treating molasses wastewater. Single-chamber MFCs without and with a proton exchange membrane (PEM), and double-chamber MFC were constructed. A total of 10,000 mg L(-1) COD of molasses wastewater was continuously fed. The COD removal, electricity generation, and microbial communities in the two types of single-chamber MFCs were similar, indicating that the PEM did not enhance the reactor performance. The COD removal in the single-chamber MFCs (89-90%) was higher than that in the double-chamber MFC (50%). However, electricity generation in the double-chamber MFC was higher than that in the single-chamber MFCs. The current density (80 mA m(-2)) and power density (17 mW m(-2)) in the double-chamber MFC were 1.4- and 2.2-times higher than those in the single-chamber MFCs, respectively. The bacterial community structures in single- and double-chamber MFCs were also distinguishable. The amount of Proteobacteria in the double-chamber MFC was 2-3 times higher than those in the single-chamber MFCs. For the archaeal community, Methanothrix (96.4%) was remarkably dominant in the single-chamber MFCs, but Methanobacterium (35.1%), Methanosarcina (28.3%), and Methanothrix (16.2%) were abundant in the double-chamber MFC.

  10. COD and Color Removal from Textile Wastewater Using Rosa damascena Watering Waste Ash

    Directory of Open Access Journals (Sweden)

    Rabbani D.1 PhD,

    2015-01-01

    Full Text Available Aims Several methods have been used for textile wastewater treatment. The aim of this study was to evaluate the efficiency of Rosa damascena watering waste ash for COD and color removal from textile wastewater. Materials & Methods Rose watering waste was gathered from one of the Kashan processing plants. The raw wastewater sample was taken from one of the textile industries in Kashan countryside. All experiments were run in the fixed volume (1L of textile wastewater, contact times (15, 30, 45, 60, 75, and 90min, pHs (3, 5, 7, and 9 and different doses of rose watering waste (500, 1000, 2000, and 4000mg at the room temperature (25°C. Moreover, biosorption kinetic studies for COD were done using the pseudo first and pseudo second order models. Findings The amount of COD and color removal were increased by contact time increasing from 15 to 60min and the maximum removal of COD (50.3% and color (31.4% were seen at minute 60. Therefore, the contact time of 60min was chosen as the optimum contact time for the first step. The maximum amount of COD (51.9% and color (32.9% removal were seen at pH=5 and biosorbent dose of 2000mg. Changes at pH and biosorbent dose had significant effects (p<0.05 on amount of COD and color removal. Conclusion The optimum condition for removing COD and color from textile wastewater is at contact time 60min, pH=5 and biosorbent dose of 2000mg. Rosa damascena watering waste ash was more effective on the COD removal than the color.

  11. Removal of chemical oxygen demand from textile wastewater using a natural coagulant

    Energy Technology Data Exchange (ETDEWEB)

    Ramavandi, Bahman [Bushehr University of Medical Sciences, Bushehr (Iran, Islamic Republic of); Farjadfard, Sima [Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2014-01-15

    A biomaterial was successfully synthesized from Plantago ovata by using an FeCl{sub 3}-induced crude extract (FCE). The potential of FCE to act as a natural coagulant was tested for the pretreatment of real textile wastewater. Tests were performed to evaluate the effects of FCE quantity, salt concentration, and wastewater pH on chemical oxygen demand (COD) reduction during a coagulation/flocculation process. Experimental results indicated that the wastewater could be effectively treated by using a coagulation/flocculation process, where the BOD{sub 5}/COD ratio of the effluent was improved to 0.48. A low coagulant dose, 1.5mg/L, achieved a high COD removal percentage, 89%, at operational conditions of neutral pH and room temperature. The experimental data revealed that the maximum COD removal occurred at water pH<8. Increasing the salt promoted the COD removal. The settling and filterability characteristics of the sludge were also studied. Scanning electron microscopy and energy dispersive spectroscopy studies were conducted to determine the sludge structure and composition, respectively. Overall, FCE as an eco-friendly biomaterial was revealed to be a very efficient coagulant and a promising option for the removal of COD from wastewaters.

  12. Long term operation of continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-09-01

    In this study, a continuous-flow system with enhanced biological phosphorus removal (EBPR) granules was operated at different COD concentrations (200, 300 and 400mgL(-)(1)) to investigate the effect of COD loading on this system. The results showed that when the COD concentration in influent was increased to 400mgL(-)(1), the anaerobic COD removal efficiency and total phosphorus removal efficiency reduced obviously and the settling ability of granules deteriorated due to the proliferation of filamentous bacteria. Moreover, high COD loading inhibited the EPS secretion and destroyed the stability of granules. Results of high-through pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading. The performance of system, settling ability of granules and proportion of PAOs gradually recovered to the initial level after the COD concentration was reduced to 200mgL(-)(1) on day 81. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Chromium (VI) biosorption and removal of chemical oxygen demand by Spirulina platensis from wastewater-supplemented culture medium.

    Science.gov (United States)

    Magro, Clinei D; Deon, Maitê C; De Rossi, Andreia; Reinehr, Christian O; Hemkemeier, Marcelo; Colla, Luciane M

    2012-01-01

    The inappropriate discharge of wastewater containing high concentrations of toxic metals is a serious threat to the environment. Given that the microalga Spirulina platensis has demonstrated a capacity for chromium VI (Cr (VI) biosorption, we assessed the ideal concentration of chromium-containing wastewater required for maximum removal of Cr (VI) and chemical oxygen demand (COD) from the environment by using this microalga. The Paracas and Leb-52 strains of S. platensis, with initial wastewater concentrations of 0%, 12.5%, 25%, and 50%, were cultured in Zarrouk medium diluted to 50% under controlled air, temperature, and lighting conditions. The cultures were maintained for 28 days, and pH, biomass growth, COD, and Cr (VI) were assessed. The wastewater concentration influenced microalgal growth, especially at high concentrations. Removal of 82.19% COD and 60.92% Cr (VI) was obtained, but the COD removal was greater than the Cr (VI) removal in both strains of S. platensis.

  14. Removal of COD and color from hydrolyzed textile azo dye by combined ozonation and biological treatment.

    Science.gov (United States)

    de Souza, Selene Maria de Arruda Guelli Ulson; Bonilla, Karin Angela Santos; de Souza, Antônio Augusto Ulson

    2010-07-15

    The application of ozonation has been increasing in recent years, the main disadvantage of this type of treatment being related to the by-products, which can have toxic and carcinogenic properties, and therefore should be studied further. In this study, the combined treatment of ozonation and subsequent biological degradation with a biofilm, to reduce the color and chemical oxygen demand (COD), was investigated. The experimental part of the study consisted of two phases. The first phase was the ozonation process, the results obtained demonstrated that the ozonation of Remazol Black B dye at pH values of 3-11, was effective, partially oxidizing and completely decolorizing the effluent, even at relatively high concentrations of the dye (500 mg/L). Color removal efficiencies greater than 96% were obtained in all cases. The degradation kinetics of ozone is a pseudo-first-order reaction with respect to the dye concentration. It was possible to verify that the ozonation process as a pre-treatment increases the dye degradation efficiency. For the biological treatment, an increase in ozonization time increased the dye concentration reduction in hydrolyzed dye synthetic effluent. The toxicological results of the tests with Daphnia Magna showed that there is an increase in toxicity after ozonization and a decrease after submitting the ozonized synthetic wastewater to biological treatment with a biofilm. 2010 Elsevier B.V. All rights reserved.

  15. Improving oxygen dissolution and distribution in a bioreactor with enhanced simultaneous COD and nitrogen removal by simply introducing micro-pressure and swirl.

    Science.gov (United States)

    Bian, Dejun; Zhou, Dandan; Huo, Mingxin; Ren, Qingkai; Tian, Xi; Wan, Liguo; Zhu, Suiyi; Ai, Shengshu

    2015-10-01

    Increasingly, environmental regulations are demanding more exacting chemical oxygen demand (COD) and nitrogen removal from wastewater, which come at a high economic cost. A very simple novel bioreactor, the micro-pressure swirl reactor (MPSR), can improve the dissolution and distribution of oxygen by the introduced micro-pressure swirl. Comparison with a conventional sequencing batch reactor (SBR) over 76 days of operation showed that this method can enhance simultaneous COD and nitrogen removal. By installing an aeration diffuser on one side of the two-dimensional MPSR, a swirl formed in the bioreactor that extended the retention time of the air bubbles. This unique flow regime, combined with the micro-pressure caused by the elevated water surface at the bubble outflow point, resulted in a higher level of dissolved oxygen (DO) in the MPSR. Aerobic and anaerobic zones that created appropriate conditions for simultaneous COD and nitrogen removal also formed in the MPSR. As the organic loading rate increased from 0.29 to 1.68 g COD/(L · day) over the test period, the COD removal efficiencies of the MPSR were generally 10-20 % greater than those of the SBR. In particular, the total nitrogen (TN) removal efficiencies of the MPSR and SBR were 40-50 and 20-35 %, respectively, whereas the TN concentrations in the MPSR effluent were always around 10 mg/L lower than those of the SBR. Further, because of the unique DO distribution, the bacterial species in the MPSR were more diverse and contributed to enhanced TN removal.

  16. Replacement of chemical oxygen demand (COD) with total organic carbon (TOC) for monitoring wastewater treatment performance to minimize disposal of toxic analytical waste.

    Science.gov (United States)

    Dubber, Donata; Gray, Nicholas F

    2010-10-01

    Chemical oxygen demand (COD) is widely used for wastewater monitoring, design, modeling and plant operational analysis. However this method results in the production of hazardous wastes including mercury and hexavalent chromium. The study examined the replacement of COD with total organic carbon (TOC) for general performance monitoring by comparing their relationship with influent and effluent samples from 11 wastewater treatment plants. Biochemical oxygen demand (BOD5) was also included in the comparison as a control. The results show significant linear relationships between TOC, COD and BOD5 in settled (influent) domestic and municipal wastewaters, but only between COD and TOC in treated effluents. The study concludes that TOC can be reliably used for the generic replacement of both COD (COD=49.2+3.00*TOC) and BOD5 (BOD5=23.7+1.68*TOC) in influent wastewaters but only for COD (COD=7.25+2.99*TOC) in final effluents.

  17. Kinetics of COD removal from a synthetic wastewater in a continuous biological fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Kargi, F. [Dept. of Environmental Engineering, Dokuz Eylul Univ., Izmir (Turkey); Karapinar, I. [Dept. of Environmental Engineering, Dokuz Eylul Univ., Izmir (Turkey)

    1995-10-01

    Kinetics of biological removal of COD from a synthetic wastewater in a continuous fluidized bed containing sponge particles with wire mesh was investigated. Synthetic wastewater consisted of diluted molasses, urea, KH{sub 2}PO{sub 4} and MgSO{sub 4} resulting in COD/N/P=100/8/1. Fluidized bed contained sponge particles surrounded by stainless steel wires as support particles for organisms. A culture of Zooglea ramigera was used as the dominant organisms in mixed culture media throughout the experiments. The system was operated continuously with different hydraulic residence times, and COD loading rates and the variation of effluent COD concentration with those parameters was investigated. Kinetic constants of the system were determined by using the continuous experimental data. System has been operated under COD limitation and DO limitations were overcome by vigirous aeration. Kinetic constants determined in this system were in good agreement with literature values with a possible inhibition effect on K{sub s} term. (orig.). With 9 figs.

  18. The effect of pH and operation mode for COD removal of slaughterhouse wastewater with Anaerobic Batch Reactor (ABR

    Directory of Open Access Journals (Sweden)

    Maria Octoviane Dyan

    2015-01-01

    Full Text Available Disposal of industrial wastes in large quantities was not in accordance with today's standards of waste into environmental issues that must be overcome with proper treatment. Similarly, the abattoir wastewater that contains too high organic compounds and suspended solids. The amount of liquid waste disposal Slaughterhouse (SW with high volume also causes pollution. The research aim to resolve this problem by lowering the levels of BOD-COD to comply with effluent quality standard. Anaerobic process is the right process for slaughterhouse wastewater treatment because of high content of organic compounds that can be utilized by anaerobic bacteria as a growth medium. Some research has been conducted among abattoir wastewater treatment using anaerobic reactors such as ABR, UASB and ASBR. Our research focuses on the search for the optimum results decline effluent COD levels to match the quality standards limbah and cow rumen fluid with biodigester ABR (Anaerobic Batch Reactor. The variables used were PH of 6, 7, and 8, as well as the concentration ratio of COD: N is 400:7; 450:7, and 500:7. COD value is set by the addition of N derived from urea [CO(NH2 2]. COD levels will be measured daily by water displacement technique. The research’s result for 20 days seen that optimum PH for biogas production was PH 7,719 ml. The optimum PH for COD removal is PH 6, 72.39 %. The operation mode COD:N for biogas production and COD removal is 500:7, with the production value is 601 ml and COD removal value is 63.85 %. The research’s conclusion, the PH optimum for biogas production was PH 7, then the optimum PH for COD removal is PH 6. The optimum operation mode COD:N for biogas production and COD removal was 500:7

  19. Protozoan biomass relation to nutrient and chemical oxygen demand removal in activated sludge mixed liquor.

    Science.gov (United States)

    Akpor, Oghenerobor B; Momba, Maggy N B; Okonkwo, Jonathan O

    2008-08-01

    The relationship between biomass concentration to nutrient and chemical oxygen demand (COD) removal in mixed liquor supplemented with sodium acetate was investigated, using three protozoan isolates and three different initial biomass concentrations (10(1), 10(2) and 10(3) cells/mL). The study was carried out in a shaking flask environment at a shaking speed of 100 rpm for 96 h at 25 degrees C. Aliquot samples were taken periodically for the determination of phosphate, nitrate, COD and dissolved oxygen, using standard methods. The results revealed remarkable phosphate removal of 82-95% at biomass concentration of 10(3)cells/mL. A high nitrate removal of over 87% was observed at all initial biomass concentration in mixed liquor. There was an observed COD increase of over 50% in mixed liquor in at the end of 96-h incubation and this was irrespective of initial biomass concentration used for inoculation. The study shows the trend in nutrient and COD removal at different biomass concentrations of the test isolates in mixed liquor.

  20. Removal of arsenic and COD from industrial wastewaters by electrocoagulation

    Directory of Open Access Journals (Sweden)

    H. POIROT

    2011-08-01

    Full Text Available The paper deals with the treatment of arsenic-containing industrial wastewaters by electrocoagulation. The waste issued from a paper mill industry downstream of the biological treatment by activated sludge was enriched with arsenic salts for the purpose of investigation of the treatment of mixed pollution. First, the treatment of single polluted waters, i.e. containing either the regular organic charge from the industrial waste or arsenic salts only, was studied. In the case of arsenic-containing waters, a broad selection of experimental data available in the literature was compiled and interpreted using an adsorption model developed previously. The same technique was used in the case of industrial waste. Arsenic-enriched paper mill wastewaters with various amounts of As salts were then treated by electrocoagulation with Fe electrodes. The set of data obtained were interpreted by a model developed on the basis of the separate models. The agreement between predicted and experimental variations of the As concentrations ranging from 0.3 µg/L to 730 µg/L showed that both the organic matter and As salt can be removed from the liquid independently from each other.

  1. Effects of COD to Phosphorus Ratios on the Metabolism of PAOs in Enhanced Biological Phosphorus Removal with Different Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    Tao Jiang; Junguo He; Xiaonan Yang; Jianzheng Li

    2015-01-01

    To elucidate the phosphorus removal and metabolism under various COD/P ratio, a sludge highly enriched in PAOs was used to investigate the impacts of COD/P in batch tests under different carbon supply conditions. Acetate, propionate and a mixture of acetate and propionate at a ratio of 3 ∶ 1 ( COD basis) was used as carbon sources with the COD/P of 20, 15,10 and 5�0 gCOD/gP, respectively. The minimum COD/P ratios for complete P removal were found to be 8�24 gCOD/gP for acetate, 11�40 gCOD/gP for propionate and 9�10 gCOD/gP for the 3 ∶ 1 mixture of acetate and propionate. Converted to a mass basis, all three cases had a very similar ratio of 7�7 gVFA/gP, which represented a useful guide for operation of EBPR plants to identify possible shortages inVFAs. The trend in PHV accumulation during the anaerobic period along with the decrease of COD/P ratios suggested that, PAOs may use the TCA pathway for anaerobic VFA uptake to maintain the required NADH production with reduced glycogen degradation. During the aerobic phase, the glycogen pool was reduced but remained enough compared to the requirement for anaerobic VFA uptake, and the synthesis and degradation of glycogen was not the inhibition factor of PAOs.

  2. Removal of colour and COD from wastewater containing acid blue 22 by electrochemical oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Panizza, Marco [Dipartimento di Ingegneria Chimica e di Processo ' G.B. Bonino' , Universita degli Studi di Genova, p.le J.F. Kennedy 1, 16129 Genova (Italy)], E-mail: marco.panizza@unige.it; Cerisola, Giacomo [Dipartimento di Ingegneria Chimica e di Processo ' G.B. Bonino' , Universita degli Studi di Genova, p.le J.F. Kennedy 1, 16129 Genova (Italy)

    2008-05-01

    Electrochemical oxidation of synthetic wastewater containing acid blue 22 on a boron-doped diamond electrode (BDD) was studied, using cyclic voltammetry and bulk electrolysis. The influence of current density, dye concentration, flow rate, and temperature was investigated, in order to find the best conditions for COD and colour removal. It was found that, during oxidation, a polymeric film, causing BDD deactivation, was formed in the potential region of water stability, and that it was removed by anodic polarisation at high potentials in the region of O{sub 2} evolution. Bulk electrolysis results showed that the electrochemical process was suitable for completely removing COD and effectively decolourising wastewaters, due to the production of hydroxyl radicals on the diamond surface. In particular, under optimal experimental conditions of flow rates (i.e. 300 dm{sup 3} h{sup -1}) and current density (i.e. 20 mA cm{sup -2}), 97% of COD was removed in 12 h electrolysis, with 70 kWh m{sup -3}energy consumption.

  3. Effects of shock 2,4-dichlorophenol (DCP) and cod loading rates on the removal of 2,4-DCP in a sequential upflow anaerobic sludge blanket/aerobic completely stirred tank reactor system.

    Science.gov (United States)

    Uluköy, A; Sponza, D T

    2008-04-01

    The treatability of 2,4-dwichlorophenol (DCP) was studied in an anaerobic/aerobic sequential reactor system. Laboratory scale upflow anaerobic sludge blanket (UASB) reactor/completely stirred tank reactors (CSTR) were operated at constant 2,4-DCP concentrations, and increasing chemical oxygen demand (COD) loading rates. The effect of shock organic loading rates on 2,4-DCP, COD removal efficiencies and methane gas production were investigated in the UASB reactor. When the organic loading rate was increased from 3.6 g l(-1) d(-1) to 30.16 g l(-1) d(-1), the COD and 2,4-DCP removal efficiencies decreased from 80 to 25% and from 99 to 60% in the UASB reactor. The optimum organic loading rates for maximum 2,4-DCP (E=99-100%) and COD (E=65-85%) removal efficiencies were 25-30 and 8-20 g-COD l(-1) d(-1), respectively. The percentage of methane of the total gas varied between 70 and 80 while the organic loadings were 18 g-COD l(-1) d(-1) and 20.36 g-COD l(-1) d(-1), respectively. During 80 days of operation, 2,4-DCP concentration was found to be below 0.5 and 0.1 mg l(-1) in aerobic reactor effluent resulting in 78 and 100% removal efficiencies. When the hydraulic retention time (HRT) was 18.72 h, the 2,4-DCP removal efficiency was 97% in the aerobic reactor. The optimum COD removal efficiency was 78.83% in anaerobic reactor effluent at an influent COD loading rate of 7.238 g-COD l(-1) d(-1) while 83.6% maximum COD removal efficiency was obtained in the aerobic reactor, resulting in a total COD removal efficiency of 96.83% in the whole system. The 2,4-DCP removal efficiency was 99% in the sequential anaerobic (UASB)/aerobic (CSTR) reactor system at COD loading rates varying between 11.46 and 30.16 g-COD l(-1) d(-1).

  4. Chemical oxygen demand removal efficiency and limited factors study of aminosilicone polymers in a water emulsion by iron-carbon micro-electrolysis.

    Science.gov (United States)

    Yang, Shangyuan; Liang, Zhiwei; Yu, Huadong; Wang, Yunlong; Chen, Yingxu

    2014-02-01

    Micro-electrolysis was applied in the present study to investigate the effect of pH, iron-carbon mass ratio, contact time, and treatment batch on the removal efficiency of chemical oxygen demand (COD) within an aminosilicone emulsion. The results exhibited that the removal efficiency of COD decreased linearly with the batch increase, and this tendency was consistent under the various conditions. The adsorption of activated carbons contributes a large portion to the elimination of COD within the aminosilicone emulsion. The oxidation action of iron-carbon micro-electrolysis was proven and the aminosilicone emulsion's COD removal contribution was approximately 16%. Aminosilicone polymers were adsorbed on the surface of activated carbons and iron chips, which contributes to the decline of COD removal efficiency and limits the contribution of oxidation action.

  5. Converting Chemical Oxygen Demand (COD) of Cellulosic Ethanol Fermentation Wastewater into Microbial Lipid by Oleaginous Yeast Trichosporon cutaneum.

    Science.gov (United States)

    Wang, Juan; Hu, Mingshan; Zhang, Huizhan; Bao, Jie

    2017-01-27

    Cellulosic ethanol fermentation wastewater is the stillage stream of distillation column of cellulosic ethanol fermentation broth with high chemical oxygen demand (COD). The COD is required to reduce before the wastewater is released or recycled. Without any pretreatment nor external nutrients, the cellulosic ethanol fermentation wastewater bioconversion by Trichosporon cutaneum ACCC 20271 was carried out for the first time. The major components of the wastewater including glucose, xylose, acetic acid, ethanol, and partial of phenolic compounds could be utilized by T. cutaneum ACCC 20271. In a 3-L bioreactor, 2.16 g/L of microbial lipid accumulated with 55.05% of COD reduced after a 5-day culture of T. cutaneum ACCC 20271 in the wastewater. The fatty acid composition of the derived microbial lipid was similar with vegetable oil, in which it could be used as biodiesel production feedstock. This study will both solve the environmental problem and offer low-cost lipid feedstock for biodiesel production.

  6. Penentuan Kadar COD (Chemical Oxygen Demand) Pada Limbah Cair Pabrik Kelapa Sawit, Pabrik Karet Dan Domestik

    OpenAIRE

    Nurhasanah

    2009-01-01

    Telah dilakukan penentuan kadar COD pada limbah cair pabrik kelapa sawit, industri karet, dan domestik dengan metode titrimetri. Dari hasil analisa COD diperoleh kadar limbah kelapa sawit sebesar 206,33mg/l, limbah industri karet sebesar 31,74 mg/l, dan limbah domestik sebesar 162,68 mg/l. dimana menurut Standart baku mutu yang telah ditetapkan oleh Menteri Lingkungan Hidup Nomor: Kep-51/MENLH/10/1995, kadar maksimum COD dalam air limbah industri kelapa sawit sebesar 350 mg/l, dalam indust...

  7. Effects of carbon sources, COD/NO2(-)-N ratios and temperature on the nitrogen removal performance of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm.

    Science.gov (United States)

    Zheng, Zhaoming; Li, Yun; Li, Jun; Zhang, Yanzhuo; Bian, Wei; Wei, Jia; Zhao, Baihang; Yang, Jingyue

    2017-04-01

    The aim of the present work was to evaluate the effects of carbon sources and chemical oxygen demand (COD)/NO2(-)-N ratios on the anammox-denitrification coupling process of the simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm. Also, the anammox activities of the SNAD biofilm were investigated under different temperature. Kaldnes rings taken from the SNAD biofilm reactor were operated in batch tests to determine the nitrogen removal rates. As a result, with the carbon source of sodium acetate, the appropriate COD/NO2(-)-N ratios for the anammox-denitrification coupling process were 1 and 2. With the COD/NO2(-)-N ratios of 1, 2, 3, 4 and 5, the corresponding NO2(-)-N consumption via anammox was 87.1%, 52.2%, 29.3%, 23.7% and 16.3%, respectively. However, with the carbon source of sodium propionate and glucose, the anammox bacteria was found to perform higher nitrite competitive ability than denitrifiers at the COD/NO2(-)-N ratio of 5. Also, the SNAD biofilm could perform anammox activity at 15 °C with the nitrogen removal rate of 0.071 kg total inorganic nitrogen per kg volatile suspended solids per day. These results indicated that the SNAD biofilm process might be feasible for the treatment of municipal wastewater at normal temperature.

  8. The effect of COD loading on the granule-based enhanced biological phosphorus removal system and the recoverability.

    Science.gov (United States)

    Yu, Shenjing; Sun, Peide; Zheng, Wei; Chen, Lujun; Zheng, Xiongliu; Han, Jingyi; Yan, Tao

    2014-11-01

    In this study, the effect of varied COD loading (200, 400, 500, 600 and 800 mg L(-1)) on stability and recoverability of granule-based enhanced biological phosphorus removal (EBPR) system was investigated during continuously 53-d operation. Results showed that COD loading higher than 500 mg L(-1) could obviously deteriorate the granular EBPR system and result in sludge bulking with filamentous bacteria. High COD loading also changed the transformation patterns of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process of polyphosphate-accumulating organisms (PAOs) and inhibited the EPS secretion, which completely destroyed the stability and integrality of granules. Results of FISH indicated that glycogen-accumulating organisms (GAOs) and other microorganisms had a competitive advantage over PAOs with higher COD loading. The community composition and EBPR performance were recovered irreversibly in long time operation when COD loading was higher than 500 mg L(-1). Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Electro Coagulation Efficiency in Removal of COD from the Qom Landfill Leahate

    Directory of Open Access Journals (Sweden)

    Mohammad Malakootian

    2012-10-01

    Full Text Available Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 Background and Objectives: leachate from municipal solid waste landfill is a strong sewage having hazardous toxic substances. It should be treated by choosing a simple, economical, and eco-friendly method. The aim of this study is reduction of COD from the Qom City landfill leachate using electrocoagulation process.   Materials and Methods: The experimental study was carried out at bench scale using a batch reactor during 2010.  We used a Plexiglas reactor having 0.7 liter capacity, containing nine plate aluminum electrodes connected to a DC power supply (10-60V, 1-5A. Samples were collected in the middle of cell at regular (every 10 minutes time intervals. The concentration of COD was determined using a COD analyzer. The effects of different parameters including current density (52.08, 69.44 mA/cm2, electrolyte time (10, 20,30,40,50 and 60 min, and voltage range (10, 20, 30, 40, 50 and 60 volt were investigated.Results: For a voltage of 60 V and electrolysis time 60 min, the COD removal efficiency was increased from 48.7% for 52.08 mA/cm2 to 77.4% for 69.44 mA/cm2. The highest TSS removal efficiency was obtained at the largest current input when the voltage and electrolysis time were kept at 60V and 60 min respectively.Conclusion: The results showed that the highest COD removal efficiency (77.4% was obtained when the current density was 69.44 Ma/cm2 and the voltage and electrolysis time were kept at 60V and 60 min respectively. Power consumption for this removal level was measured to be 431.26 kWh per kg COD removal. The results obtained revealed that the electrocoagulation technology is an effective treatment process for landfill leachate. st1":*{behavior:url(#ieooui } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso

  10. Effect of COD/N ratio on nitrogen removal and microbial communities of CANON process in membrane bioreactors.

    Science.gov (United States)

    Zhang, Xiaojing; Zhang, Hongzhong; Ye, Changming; Wei, Mingbao; Du, Jingjing

    2015-08-01

    In this study, the effect of COD/N ratio on completely autotrophic nitrogen removal over nitrite (CANON) process was investigated in five identical membrane bioreactors. The five reactors were simultaneously seeded for 1L CANON sludge and be operated for more than two months under same conditions, with influent COD/N ratio of 0, 0.5, 1, 2 and 4, respectively. DGGE was used to analyze the microbial communities of aerobic ammonia-oxidizing bacteria (AOB) and anaerobic ammonia-oxidizing bacteria (AAOB) in five reactors. Results revealed the harmonious work of CANON and denitrification with low COD concentration, whereas too high COD concentration suppressed both AOB and AAOB. AOB and AAOB biodiversity both decreased with COD increasing, which then led to worse nitrogen removal. The suppressing threshold of COD/N ratio for CANON was 1.7. CANON was feasible for treating low COD/N sewage, while the high sewage should be converted by anaerobic biogas producing process in advance.

  11. Nitrogen and COD Removal from Septic Tank Wastewater in Subsurface Flow Constructed Wetlands: Plants Effects.

    Science.gov (United States)

    Collison, R S; Grismer, M E

    2015-11-01

    We evaluated subsurface flow (SSF) constructed wetland treatment performance with respect to organics (COD) and nitrogen (ammonium and nitrate) removal from domestic (septic tank) wastewater as affected by the presence of plants, substrate "rock" cation exchange capacity (CEC), laboratory versus field conditions and use of synthetic as compared to actual domestic wastewater. This article considers the effects of plants on constructed wetland treatment in the field. Each constructed wetland system was comprised of two beds (2.6 m long by 0.28 m wide and deep filled with ~18 mm crushed lava rock) separated by an aeration tank connected in series. The lava rock had a porosity of ~47% and a CEC of 4 meq/100 gm. One pair of constructed wetland systems was planted with cattails in May 2008, while an adjacent pair of systems remained un-planted. Collected septic tank or synthesized wastewater was allowed to gravity feed each constructed wetland system and effluent samples were regularly collected and tested for COD and nitrogen species during four time periods spanning November 2008 through June 2009. These effluent concentrations were tested for statistical differences at the 95% level for individual time periods as well as the overall 6-month period. Organics removal from domestic wastewater was 78.8% and 76.1% in the planted and un-planted constructed wetland systems, respectively, while ammonium removal was 94.5% and 90.2%, respectively. Similarly, organics removal from the synthetic wastewater of equivalent strength was 88.8% and 90.1% for planted and un-planted constructed wetland systems, respectively, while ammonium removal was 96.9% and 97.3%, respectively.

  12. Efficiency of horizontal roughing filter in removing nitrate, phosphate and chemical oxygen demand from effluent of waste stabilization pond

    Directory of Open Access Journals (Sweden)

    Seyed Mostafa Khezri

    2015-06-01

    Full Text Available Background: The effective size of the end grain of horizontal roughing filters (HRFs is larger than 2 mm. This study aimed to examine the efficiency of HRFs in removing nitrate, phosphate, and chemical oxygen demand (COD from effluent of a wastewater stabilization pond. Methods: This experimental study was conducted in 2013. The pilot project was transferred to the Karaj wastewater treatment plant (stabilization pond, and the installation, equipping, and start-up of the system began using an effluent treatment plant. Sampling was done from March to August in 3 rates, 0.5, 1 and 1.5 m/h, and included simultaneous sampling from inlet and outlet filtering to determine the concentrations of nitrate, phosphate, and COD. Results: At filtration rates of 0.5, 1, and 1.5 m/h, the average nitrate removal equaled 25%, 32%, and 34%, respectively, average phosphate removal equaled 29%, 26%, and 28%, respectively, and the average COD removal at filtration rates of 0.5, 1, and 1.5 m/h equaled 62%, 66%, and 68%, respectively. Outlet values of phosphate and nitrate were lower than the standards set by the Environmental Standards Organization (ESO (P < 0.05. Conclusion: According to the results of this study, the HRF function was approximately adequate in COD removal, but its efficiency in nitrate and phosphate removal was lower.

  13. Effect of rhamnolipid on the aerobic removal of polyaromatic hydrocarbons (PAHs) and COD components from petrochemical wastewater.

    Science.gov (United States)

    Sponza, Delia Teresa; Gök, Oğuzhan

    2010-02-01

    The removal efficiencies of 15 PAHs and some COD components (inert, readily degradable, slowly degradable and metabolic products) from a wastewater taken from a petrochemical industry treatment plant (Izmir, Turkey) have been determined using an aerobic completely stirred tank reactor (CSTR). Addition of rhamnolipid surfactant (15 mg l(-1)) increased the removal efficiencies of PAHs and soluble COD from 72% and 90% to 80% and 99%, respectively. The rhamnolipid treatment caused a significant increase of 5- and 6-ring PAH degradation. The soluble COD removal efficiency was 93%, in CSTR reactors with rhamnolipid added. The inert COD removal efficiency was 60% in a CSTR reactor containing rhamnolipid. Batch tests showed that removal arising from the adsorption of the PAHs was low (between 1.88% and 4.84%) while the removal of PAHs from the petrochemical industry wastewater via volatilization varied between 0.69% and 5.92%. Low sorption capacity (K(p)) values for refinery activated sludge (approximately 2.98 l g(-1)) confirmed that bio-sorption was not an important mechanism controlling the fate of PAHs in aerobic CSTR reactors. Models proposed to simulate the PAH removal indicated that 94% of the PAHs were removed via biodegradation.

  14. Effect of spent cotton stalks on color removal and chemical oxygen demand lowering in olive oil mill wastewater by white rot fungi.

    Science.gov (United States)

    Kahraman, S; Yeşilada, O

    1999-01-01

    Wastewater from olive oil mill was decolorized (and its chemical oxygen demand reduced in static cultivation) using the fungi Coriolus versicolor, Funalia trogii, Phanerochaete chrysosporium and Pleurotus sajor-caju. The effect of cotton stalk on decolorizing and COD removing capability was demonstrated. P. chrysosporium (in 20% medium with cotton stalk) reduced the COD by 48% and color by 58%, F. trogii (in 30% medium with cotton stalk)) by 51 and 55%, respectively.

  15. Relationships between chemical oxygen demand (COD) components and toxicity in a sequential anaerobic baffled reactor/aerobic completely stirred reactor system treating Kemicetine.

    Science.gov (United States)

    Sponza, Delia Teresa; Demirden, Pinar

    2010-04-15

    In this study the interactions between toxicity removals and Kemicetine, COD removals, intermediate products of Kemicetine and COD components (CODs originating from slowly degradable organics, readily degradable organics, inert microbial products and from the inert compounds) were investigated in a sequential anaerobic baffled reactor (ABR)/aerobic completely stirred tank reactor (CSTR) system with a real pharmaceutical wastewater. The total COD and Kemicetine removal efficiencies were 98% and 100%, respectively, in the sequential ABR/CSTR systems. 2-Amino-1 (p-nitrophenil)-1,3 propanediol, l-p-amino phenyl, p-amino phenol and phenol were detected in the ABR as the main readily degradable inter-metabolites. In the anaerobic ABR reactor, the Kemicetin was converted to corresponding inter-metabolites and a substantial part of the COD was removed. In the aerobic CSTR reactor the inter-metabolites produced in the anaerobic reactor were completely removed and the COD remaining from the anerobic reactor was biodegraded. It was found that the COD originating from the readily degradable organics did not limit the anaerobic degradation process, while the CODs originating from the slowly degradable organics and from the inert microbial products significantly decreased the anaerobic ABR reactor performance. The acute toxicity test results indicated that the toxicity decreased from the influent to the effluent of the aerobic CSTR reactor. The ANOVA test statistics showed that there was a strong linear correlation between acute toxicity, CODs originating from the slowly degradable organics and inert microbial products. A weak correlation between acute toxicity and CODs originating from the inert compounds was detected.

  16. COD removal from pulp and paper effluents by Advanced Oxidation Processes (AOP); COD:n vaehentaeminen aop-menetelmaellae metsaeteollisuuden jaetevesistae - EKY 04

    Energy Technology Data Exchange (ETDEWEB)

    Jansson, K.; Wikberg, H. [Kemira Chemicals Oy, Vaasa (Finland)

    1998-12-31

    The aim of this project is to develop a process where COD from pulp and paper industry can be removed by an AOP process. AOP is a process utilizing the oxidation power of the hydroxyl radical, which can be produced in many different ways. Compared to evaporation and membrane techniques, the benefits of this process are lack of condense, concentrate and sludge. It is a very simple process, based on adjusting the COD removal by means of hydrogen peroxide dosage. The study focuses on using heterogeneous catalyst together with hydrogen peroxide to produce hydroxyl radicals in order to remove COD at low temperatures (< 100 deg C) and normal pressures. The project started by screening catalysts able to perform this task in laboratory scale. Later on pilot scale equipment will be constructed for use in pulp and paper mill trials. The project will be carried out during 1997-1999. The study started by screening the possibilities of different catalysts together with hydrogen peroxide to remove phenols from a model water. Sofar, about hundred catalysts have been screened. These tests show that many of the heterogeneous catalysts are working, but most of them have actually dissolved in the water and `translated` to homogenous catalysts. This means that they cannot be used in this project. A few catalysts have been found to meet the targets for synthetic phenol waters. Next step will be to test these catalysts on actual water samples from pulp and paper mills, and after that a pilot and full-scale trial will be planned. In these trials we will find out which mill streams are possible to treat, and the cost/performances of a system totally based on the catalyst in use. Also, measurements of catalyst leaching and clogging will be made during these tests. The last test series is planned to be a full-scale trial. (orig.)

  17. The removal of COD and color by Fenton oxidation from leachate of Erzurum municipal solid waste landfill

    Science.gov (United States)

    Kocakaplan, Nihal; Ertugay, Neşe; Malkoç, Emine

    2016-04-01

    The optimal conditions for treatment of leachate were determined as pH = 2.5, Fe2+= 2 mg/L and H2O2= 100 mg/L. Under the optimal conditions, approximately 90% color (at 620 nm), 84% color (at 525 nm), 74% color (at 436 nm) and 47.8% COD removal efficiency from leachate were achieved after 20 min of reaction. Depending on the results obtained experiments, Fenton process has been used successfully in removal of COD and color in landfill leachate.

  18. Artificial intelligence based model for optimization of COD removal efficiency of an up-flow anaerobic sludge blanket reactor in the saline wastewater treatment.

    Science.gov (United States)

    Picos-Benítez, Alain R; López-Hincapié, Juan D; Chávez-Ramírez, Abraham U; Rodríguez-García, Adrián

    2017-03-01

    The complex non-linear behavior presented in the biological treatment of wastewater requires an accurate model to predict the system performance. This study evaluates the effectiveness of an artificial intelligence (AI) model, based on the combination of artificial neural networks (ANNs) and genetic algorithms (GAs), to find the optimum performance of an up-flow anaerobic sludge blanket reactor (UASB) for saline wastewater treatment. Chemical oxygen demand (COD) removal was predicted using conductivity, organic loading rate (OLR) and temperature as input variables. The ANN model was built from experimental data and performance was assessed through the maximum mean absolute percentage error (= 9.226%) computed from the measured and model predicted values of the COD. Accordingly, the ANN model was used as a fitness function in a GA to find the best operational condition. In the worst case scenario (low energy requirements, high OLR usage and high salinity) this model guaranteed COD removal efficiency values above 70%. This result is consistent and was validated experimentally, confirming that this ANN-GA model can be used as a tool to achieve the best performance of a UASB reactor with the minimum requirement of energy for saline wastewater treatment.

  19. SEASONAL CHANGES IN NITROGEN, PHOSPHORUS, BOD AND COD REMOVAL IN BYSTRE WASTEWATER TREATMENT PLANT

    Directory of Open Access Journals (Sweden)

    Iwona Skoczko

    2017-07-01

    Full Text Available The aim of this study was to determinate seasonal changes in industrial wastewater treatment effectiveness. Studies were carried out in mechanical-biological wastewater treatment plant in Bystre near Giżycko to which inflows mixture of domestic and dairy wastewater. Laboratory studies were carried out by Water and Wastewater Company in Giżycko. For statistical analysis results form years 2014 and 2015 were considered. The scope of statistical analysis includes basic statistical measures including arithmetic mean, median, minimum, maximum and standard deviation. Changes in seasonal treatment effectiveness were shown by Fisher-Snedecore LSD test. Seasonal changes were observed for BOD, COD and total nitrogen removal effectiveness. Total phosphorus was not subjected to that kind of changes.

  20. Characteristic of COD removal and sludge settleability in biological treatment of hypersaline wastewater

    Institute of Scientific and Technical Information of China (English)

    ZHU Gui-bing; PENG Yong-zhen; MENG Xiang-sheng; CUI You-wei; SUN Ya-nan

    2006-01-01

    In order to investigate the feasibility of biological treatment of hypersaline wastewater produced from toilet flushing with seawater at low temperature, pilot-scale studies were established with plug-flow activated sludge process at low temperature (5-9℃) based on bench-scale experiments. The critical salinity concentration of 30 g/L, which resulted from the cooperation results of the non-halophilic bacteria and the halophilic bacteria, was drawn in bench-scale experiment. Pilot-scale studies showed that high COD removal efficiency, higher than 85 %, was obtained at low temperature when 30 percent seawater [ seawater/( seawater + sewage) ] was introduced. The salinity improved the settleability of activated sludge, and average SV dropped down from 38%to 22. 5% after adding seawater. Sludge bulking could be forborne effectively because filamentous bacteria couldn' t subsist under high salinity concentration.

  1. Nitrogen removal performance in planted and unplanted horizontal subsurface flow constructed wetlands treating different influent COD/N ratios.

    Science.gov (United States)

    Wang, Wei; Ding, Yi; Ullman, Jeffrey L; Ambrose, Richard F; Wang, Yuhui; Song, Xinshan; Zhao, Zhimiao

    2016-05-01

    Microcosm horizontal subsurface flow constructed wetlands (HSSFCWs) were used to examine the impacts of vegetation on nitrogen dynamics treating different influent COD/N ratios (1:1, 4:1, and 8:1). An increase in the COD/N ratio led to increased reductions in NO3 and total inorganic nitrogen (TIN) in planted and unplanted wetlands, but diminished removal of NH4. The HSSFCW planted with Canna indica L. exhibited a significant reduction in NH4 compared to the unplanted system, particularly in the active root zone where NH4 removal performance increased by up to 26 % at the COD/N ratio of 8:1. There was no significant difference in NO3 removal between the planted and unplanted wetlands. TIN removal efficiency in the planted wetland increased with COD/N ratios, which was likely influenced by plant uptake. NH4 reductions were greater in planted wetland at the 20- and 40-cm depths while NO3 reductions were uniformly greater with depth in all cases, but no statistical difference was impacted by depth on TIN removal. These findings show that planting a HSSFCW can provide some benefit in reducing nitrogen loads in effluents, but only when a sufficient carbon source is present.

  2. Cultivation of Chlorella vulgaris JSC-6 with swine wastewater for simultaneous nutrient/COD removal and carbohydrate production.

    Science.gov (United States)

    Wang, Yue; Guo, Wanqian; Yen, Hong-Wei; Ho, Shih-Hsin; Lo, Yung-Chung; Cheng, Chieh-Lun; Ren, Nanqi; Chang, Jo-Shu

    2015-12-01

    Swine wastewater, containing a high concentration of COD and ammonia nitrogen, is suitable for the growth of microalgae, leading to simultaneous COD/nutrients removal from the wastewater. In this study, an isolated carbohydrate-rich microalga Chlorella vulgaris JSC-6 was adopted to perform swine wastewater treatment. Nearly 60-70% COD removal and 40-90% NH3-N removal was achieved in the mixotrophic and heterotrophic culture, depending on the dilution ratio of the wastewater, while the highest removal percentage was obtained with 20-fold diluted wastewater. Mixotrophic cultivation by using fivefold diluted wastewater resulted in the highest biomass concentration of 3.96 g/L. The carbohydrate content of the microalga grown on the wastewater can reach up to 58% (per dry weight). The results indicated that the microalgae-based wastewater treatment can efficiently reduce the nutrients and COD level, and the resulting microalgal biomass had high carbohydrate content, thereby having potential applications for the fermentative production of biofuels or chemicals.

  3. Comparison of the cost and efficiency of Aluminum and Iron electrodes application in the removal of phosphate, nitrate, and COD from laundry wastewater using electrocoagulation process

    Directory of Open Access Journals (Sweden)

    Marzieh Razavi

    2014-03-01

    Conclusion: Although application of both iron and aluminum electrodes lead to obtaining considerable removal phosphate, nitrate and COD, iron electrodes could result in reasonable removals to meet Environmental Standards with lower operational costs.

  4. Fine-tuning key parameters of an integrated reactor system for the simultaneous removal of COD, sulfate and ammonium and elemental sulfur reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Ye, E-mail: yuanye_19840915@163.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chen, Chuan, E-mail: echo110244@126.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Liang, Bin, E-mail: liangbin1214@163.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Huang, Cong, E-mail: hengyue5257@163.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Zhao, Youkang, E-mail: zhaoyoukang@gmail.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Xu, Xijun, E-mail: xuxijun3220@sina.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Tan, Wenbo, E-mail: tanwenbo1@163.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Zhou, Xu, E-mail: x.zhou@awmc.uq.edu.au [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Gao, Shuang, E-mail: localinna.1990@163.com [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Sun, Dezhi, E-mail: sundezhi@bjfu.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, DuuJong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); and others

    2014-03-01

    Graphical abstract: - Highlights: • The system achieved simultaneous removal of 98% COD, 98% sulfate and 78% nitrogen. • The HRTs and reflux ratios were key parameters for performance and S{sup 0} recovery. • 60% S{sup 0} reclaimed from effluent, 30% deposited in reactor S{sup 0} (S{sup 0} production ≈ 90%). • Characteristics of bio-S{sup 0} were targeted to acquire high-rate S{sup 0} recovery. • Microbial community succession and function were discussed at different stage. - Abstract: In this paper, we proposed an integrated reactor system for simultaneous removal of COD, sulfate and ammonium (integrated C-S-N removal system) and investigated the key parameters of the system for a high level of elemental sulfur (S{sup 0}) production. The system consisted of 4 main units: sulfate reduction and organic carbon removal (SR-CR), autotrophic and heterotrophic denitrifying sulfide removal (A and H-DSR), sulfur reclamation (SR), and aerated filter for aerobic nitrification (AN). In the system, the effects of key operational parameters on production of elemental sulfur were investigated, including hydraulic retention time (HRT) of each unit, sulfide/nitrate (S{sup 2−}-S/NO{sub 3}{sup −}-N) ratios, reflux ratios between the A and H-DSR and AN units, and loading rates of chemical oxygen demand (COD), sulfate and ammonium. Physico-chemical characteristics of biosulfur were studied for acquiring efficient S{sup 0} recovery. The experiments successfully explored the optimum parameters for each unit and demonstrated 98% COD, 98% sulfate and 78% nitrogen removal efficiency. The optimum HRTs for SR-CR, A and H-DSR and AN were 12 h, 3 h and 3 h, respectively. The reflux ratio of 3 could provide adequate S{sup 2−}-S/NO{sub 3}{sup −}-N ratio (approximately 1:1) to the A and H-DSR unit for obtaining maximum sulfur production. In this system, the maximum production of S{sup 0} reached 90%, but only 60% S{sup 0} was reclaimed from effluent. The S{sup 0} that adhered

  5. Immobilizing of catalyst using Bayah's natural zeolite to reduce the chemical oxygen demand (COD) and total organic carbon (TOC)

    Science.gov (United States)

    Jayanudin, Kustiningsih, Indar; Sari, Denni Kartika

    2017-05-01

    Indonesia is rich of natural minerals, many of which had not been widely used. One potential natural mineral is zeolite from Bayah Banten that can be used to support catalyst in the process of waste degradation. The purpose of this research is to characterize the Bayah's zeolite and to figure out the effectiveness of the zeolite as supporting agent to the Fe catalyst in the process of phenol degradation, with the main purposes are to reduce the Chemical Oxygen Demand (COD) and Total Organic Carbon (TOC). This research consists of three steps, activation of natural zeolite using 1M, 2M, and 3M NaOH solution, impregnation process with 0.025M, 0.05 M and 0.075M Fe(NO3)3.9H2O solution, and calcination at 500°C. Bayah's natural zeolite was characterize using Brauner-Emmet-Teller (BET) for its pore area, X-ray Fluorescence (XRF) for analyzing zeolite's component before and after activation process and after impregnation process, and Scanning Electron Microscope (SEM) for analyzing zeolite's morphology. The result showed that the highest pore area was 9Å, Fe metal from Fe(NO3)3.9H2O 0,075 M solution remained in zeolite pore was 7,73%, the reduction of COD and TOC was yielded at H2O2: phenol ratio of 1 : 6.

  6. Effect of sludge retention time on continuous-flow system with enhanced biological phosphorus removal granules at different COD loading.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-11-01

    The effect of sludge retention time (SRT) on the continuous-flow system with enhanced biological phosphorus removal (EBPR) granules at different COD loading was investigated during the operation of more than 220days. And the results showed that when the system operated at long SRT (30days) and low COD loading (200mg·L(-1)), it could maintain excellent performance. However, long SRT and high COD loading (300mg·L(-1)) deteriorated the settling ability of granules and the performance of system and resulted in the overgrowth of filamentous bacteria. Meanwhile, the transformation of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process was inhibited. Moreover, the results of pyrosequencing indicated that filamentous bacteria had a competitive advantage over polyphosphate-accumulating organisms (PAOs) at high COD loading and long SRT. The PAOs specious of Candidatus_Accumlibater and system performance increased obviously when the SRT was reduced to 20days at high COD loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Electrochemical treatment of rice grain-based distillery effluent: chemical oxygen demand and colour removal.

    Science.gov (United States)

    Prajapati, Abhinesh Kumar; Chaudhari, Parmesh Kumar

    2014-01-01

    The electrochemical (EC) treatment of rice grain-based distillery wastewater was carried out in a 1.5 dm3 electrolytic batch reactor using aluminium plate electrodes. With the four-plate configurations, a current density (j) of 89.3 A/m2 and pH 8 was found to be optimal, obtaining a maximum chemical oxygen demand (COD) and colour removal of 93% and 87%, respectively. The chemical dissolution of aluminium was strongly influenced by initial pH (pHi). At higher pHi (pH 9.5) anode consumption decreased while energy consumption increased. At the optimal current density 89.3 A/m2, the aluminium electrode consumption was 16.855 g/dm3 wastewater and energy consumption was 31.4 Wh/dm3 achieving a maximum COD removal of 87%. The settling and filterability characteristics ofelectrochemically treated sludge were also analysed at different pH. It was noted that treated slurry at pHi 9.5 gave best settling characteristic, which decreased with increase in pH. EC-treated effluent at pHi 8 had provided best filterability. Characteristics of scum and residues are also analysed at different pH.

  8. Hierarchical eco-restoration: a systematical approach to removal of COD and dissolved nutrients from an intensive agricultural area.

    Science.gov (United States)

    Wu, Yonghong; Hu, Zhengyi; Yang, Linzhang

    2010-10-01

    A systematical approach based on hierarchical eco-restoration system for the simultaneous removal of COD and dissolved nutrients was proposed and applied in a complex residential-cropland area in Kunming, China from August 2006 to August 2008, where the self-purifying capacity of the agricultural ecosystem had been lost. The system includes four main parts: (1) fertilizer management and agricultural structure optimization, (2) nutrients reuse, (3) wastewater treatment, and (4) catchment restoration. The results showed that the average removal efficiencies were 90% for COD, 93% for ammonia, 94% for nitrate and 71% for total dissolved phosphorus (TDP) when the hierarchical eco-restoration agricultural system was in a relatively steady-state condition. The emergence of 14 species of macrophytes and 4 species of zoobenthos indicated that the growth conditions for the plankton were improved. The results demonstrated that this promising and environmentally benign hierarchical eco-restoration system could decrease the output of nutrients and reduce downstream eutrophication risk.

  9. Achieving low effluent NO3-N and TN concentrations in low influent chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio without using external carbon source

    Science.gov (United States)

    Cao, Jiashun; Oleyiblo, Oloche James; Xue, Zhaoxia; Otache, Y. Martins; Feng, Qian

    2015-07-01

    Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal (BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, anaerobic anoxic oxic (A2/O). The ASM2d implemented on the platform of WEST2011 software and the BioWin activated sludge/anaerobic digestion (AS/AD) models were used in this study with the aim of consistently achieving the designed effluent criteria at a low operational cost. Four ASM2d parameters (the reduction factor for denitrification , the maximum growth rate of heterotrophs (µH), the rate constant for stored polyphosphates in PAOs ( q pp), and the hydrolysis rate constant ( k h)) were adjusted. Whereas three BioWin parameters (aerobic decay rate ( b H), heterotrophic dissolved oxygen (DO) half saturation ( K OA), and Y P/acetic) were adjusted. Calibration of the two models was successful; both models have average relative deviations (ARD) less than 10% for all the output variables. Low effluent concentrations of nitrate nitrogen (N-NO3), total nitrogen (TN), and total phosphorus (TP) were achieved in a full-scale BNR treatment plant having low influent chemical oxygen demand (COD) to total Kjeldahl nitrogen (TKN) ratio (COD/TKN). The effluent total nitrogen and nitrate nitrogen concentrations were improved by 50% and energy consumption was reduced by approximately 25%, which was accomplished by converting the two-pass aerobic compartment of the plug-flow bioreactor to anoxic reactors and being operated in an alternating mode. Findings in this work are helpful in improving the operation of wastewater treatment plant while eliminating the cost of external carbon source and reducing energy consumption.

  10. [Simultaneously removal of COD, nitrogen and phosphorus from wastewater by coupling treatment system with immobilized algae-bacteria].

    Science.gov (United States)

    Deng, Xu; Wei, Bin; Hu, Zhang-Li

    2011-08-01

    A coupling treatment system was developed by employing immobilized Chlamydomonas reinhardti and activated sludge to simultaneously remove COD, nitrogen and phosphorus from wastewater. The amount of wastewater treated by the system was 6 m3 per day, and hydraulic retention time was 12 h. For activated sludge section, as stirring rate of anaerobic tank was 15 r x min(-1) and DO value of aerobic tank was 5 mg x L(-1), COD decreased from about 150 mg x L(-1) to 50 mg x L(-1) and NH4+-N from 20-30 mg x L(-1) to 0.5 mg x L(-1), whereas TP only dropped from 2-3 mg x L(-1) to 1.0 mg x L(-1). For immobilized C. reinhardti section, the suitable conditions were: DO 5 mg x L(-1), illumination intensity 2000 lx, the loading ratio of immobilization pellets 20%, respectively. Under the appropriate conditions of the coupling treatment system, COD, NH4+-N and TP of the effluent were about 15 mg x L(-1), 0.5 mg x L(-1) and 0.5 mg x L(-1), respectively. During 2 months period of continuous treatment, COD, NH4+-N and TP of the effluent kept fairly constant, showing the stability of the coupling wastewater treatment system.

  11. Application of response surface methodology (RSM) for optimisation of COD, NH3-N and 2,4-DCP removal from recycled paper wastewater in a pilot-scale granular activated carbon sequencing batch biofilm reactor (GAC-SBBR).

    Science.gov (United States)

    Muhamad, Mohd Hafizuddin; Sheikh Abdullah, Siti Rozaimah; Mohamad, Abu Bakar; Abdul Rahman, Rakmi; Hasan Kadhum, Abdul Amir

    2013-05-30

    In this study, the potential of a pilot-scale granular activated carbon sequencing batch biofilm reactor (GAC-SBBR) for removing chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N) and 2,4-dichlorophenol (2,4-DCP) from recycled paper wastewater was assessed. For this purpose, the response surface methodology (RSM) was employed, using a central composite face-centred design (CCFD), to optimise three of the most important operating variables, i.e., hydraulic retention time (HRT), aeration rate (AR) and influent feed concentration (IFC), in the pilot-scale GAC-SBBR process for recycled paper wastewater treatment. Quadratic models were developed for the response variables, i.e., COD, NH3-N and 2,4-DCP removal, based on the high value (>0.9) of the coefficient of determination (R(2)) obtained from the analysis of variance (ANOVA). The optimal conditions were established at 750 mg COD/L IFC, 3.2 m(3)/min AR and 1 day HRT, corresponding to predicted COD, NH3-N and 2,4-DCP removal percentages of 94.8, 100 and 80.9%, respectively.

  12. The use of artificial neural network (ANN) for modeling of COD removal from antibiotic aqueous solution by the Fenton process.

    Science.gov (United States)

    Elmolla, Emad S; Chaudhuri, Malay; Eltoukhy, Mohamed Meselhy

    2010-07-15

    The study examined the implementation of artificial neural network (ANN) for the prediction and simulation of antibiotic degradation in aqueous solution by the Fenton process. A three-layer backpropagation neural network was optimized to predict and simulate the degradation of amoxicillin, ampicillin and cloxacillin in aqueous solution in terms of COD removal. The configuration of the backpropagation neural network giving the smallest mean square error (MSE) was three-layer ANN with tangent sigmoid transfer function (tansig) at hidden layer with 14 neurons, linear transfer function (purelin) at output layer and Levenberg-Marquardt backpropagation training algorithm (LMA). ANN predicted results are very close to the experimental results with correlation coefficient (R(2)) of 0.997 and MSE 0.000376. The sensitivity analysis showed that all studied variables (reaction time, H(2)O(2)/COD molar ratio, H(2)O(2)/Fe(2+) molar ratio, pH and antibiotics concentration) have strong effect on antibiotic degradation in terms of COD removal. In addition, H(2)O(2)/Fe(2+) molar ratio is the most influential parameter with relative importance of 25.8%. The results showed that neural network modeling could effectively predict and simulate the behavior of the Fenton process. 2010 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2016-07-01

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

  14. Application of novel consortium TSR for treatment of industrial dye manufacturing effluent with concurrent removal of ADMI, COD, heavy metals and toxicity.

    Science.gov (United States)

    Patel, Tallika L; Patel, Bhargav C; Kadam, Avinash A; Tipre, Devayani R; Dave, Shailesh R

    2015-01-01

    The present study was aimed towards the effective bio-treatment of actual industrial effluent containing as high as 42,000 mg/L COD (chemical oxygen demand), >28,000 ADMI (American Dye Manufacturers Institute) color value and four heavy metals using indigenous developed bacterial consortium TSR. Mineral salt medium supplemented with as low as 0.02% (w/v) yeast extract and glucose was found to remove 70% ADMI, 69% COD and >99% sorption of heavy metals in 24 h from the effluent by consortium TSR. The biodegradation of effluent was monitored by UV-vis light, HPLC (high performance liquid chromatography), HPTLC (high performance thin layer chromotography) and FTIR (Fourier transform infrared spectroscopy) and showed significant differences in spectra of untreated and treated effluent, confirming degradation of the effluent. Induction of intracellular azoreductase (107%) and NADH-DCIP reductase (128%) in addition to extracellular laccase (489%) indicates the vital role of the consortium TSR in the degradation process. Toxicity study of the effluent using Allium cepa by single cell gel electrophoresis showed detoxification of the effluent. Ninety per cent germination of plant seeds, Triticum aestivum and Phaseolus mungo, was achieved after treatment by consortium TSR in contrast to only 20% and 30% germination of the respective plants in case of untreated effluent.

  15. APPLICATION OF ELECTROCHEMICAL METHODS FOR DECREASING OF CHEMICAL OXYGEN DEMAND (COD AND TOTAL SUSPENDED SOLID (TSS OF TOFU INDUSTRIAL WASTEWATER

    Directory of Open Access Journals (Sweden)

    Suyata

    2015-05-01

    Full Text Available Tofu industrial wastewater has high COD and TSS level, which it cause an environmental pollution. Therefore, it is necessary to decrease the value of COD and TSS of tofu industrial wastewater before discharge into the water body. Decreasing of COD and TSS values can be carried out using an electrochemical method. The purpose of this research was to determine the effect of potential, electrode distance, pH, and time to decrease of COD and TSS value of the tofu industrial wastewater. The experiment has been performed by electrolysis tofu industrial wastewater using PbO2 as anode and Pb as cathode. The result of the research showed that under the optimum conditions of 12 V voltage, 1 cm electrode distance, pH 1, and electrolysis time of 120 minutes, decreasing COD and TSS of 96.33% and 87.87% respectively

  16. COD removal from real semi-coke wastewater by electro-Fenton technology%电芬顿法去除兰炭废水COD

    Institute of Scientific and Technical Information of China (English)

    毕强; 薛娟琴; 郭莹娟; 李国平; 雷美美

    2012-01-01

    An improved electro-Fenton technology with stainless steel anode and cathode of graphite-based gas diffusion electrode is introuced in this work to enhance removal rate of COD in semi-coke wastewater which is famous for high treatment cost as its biodegradation is hard. By several exhaustive experiments, the optimum re- moval rate of COD is up to 78.62% at the optimized conditions in the laboratory of the oxygen sparging rates of 2.5 L/min, the optimal electrode plates distance of 2 cm, current density of 5.2 mA/cm2 , solution pH of 3, and duration of 240 min, which provides a high efficiency pretreatment for semi-coke wastewater, and an promis- ing new method for the treatment of non-biodegradable high concetration wastewater in the future.%为处理高浓度生物难降解兰炭废水,考查了利用不锈钢作阳极和石墨气体扩散电极作阴极构成的电芬顿体系对兰炭废水COD的去除效果。系统地考察了空气流速、电流密度、溶液pH值及极板间距等因素对废水COD去除率的影响。电解过程的较佳条件:空气流速为2.5L/min;电流密度为5.2mA/cm^2;溶液pH值为3;极板间距为2cm。电芬顿法处理兰炭废水240min之后,COD最高去除率可达78.62%,实现了对兰炭废水的预处理,为兰炭废水的处理提供了新的途径。

  17. Enhanced removal of chemical oxygen demand, nitrogen and phosphorus using the ameliorative anoxic/anaerobic/oxic process and micro-electrolysis.

    Science.gov (United States)

    Bao, K Q; Gao, J Q; Wang, Z B; Zhang, R Q; Zhang, Z Y; Sugiura, N

    2012-01-01

    Synthetic wastewater was treated using a novel system integrating the reversed anoxic/anaerobic/oxic (RAAO) process, a micro-electrolysis (ME) bed and complex biological media. The system showed superior chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) removal rates. Performance of the system was optimised by considering the influences of three major controlling factors, namely, hydraulic retention time (HRT), organic loading rate (OLR) and mixed liquor recirculation (MLR). TP removal efficiencies were 69, 87, 87 and 83% under the HRTs of 4, 8, 12 and 16 h. In contrast, HRT had negligible effects on the COD and TN removal efficiencies. COD, TN and TP removal efficiencies from synthetic wastewater were 95, 63 and 87%, respectively, at an OLR of 1.9 g/(L·d). The concentrations of COD, TN and TP in the effluent were less than 50, 15 and 1 mg/L, respectively, at the controlled MLR range of 75-100%. In this system, organics, TN and TP were primarily removed from anoxic tank regardless of the operational conditions.

  18. Removal of COD, phenols and ammonium from Lurgi coal gasification wastewater using A2O-MBR system.

    Science.gov (United States)

    Wang, Zixing; Xu, Xiaochen; Gong, Zheng; Yang, Fenglin

    2012-10-15

    As a typical industrial wastewater, coal gasification wastewater has poor biodegradability and high toxicity. In this paper, a laboratory-scale anaerobic-anoxic-oxic membrane reactor (A(2)O-MBR) system was developed to investigate the treatment ability of coal gasification wastewater. The removal capacity of each pollutants used in this system were determined at different hydraulic residence times (HRT) and mixed liquor recycle ratios (R). The experimental results showed that this system could effectively deal with COD and phenol removal and remain in a stable level when the operational parameters altered, while the nitrification was sensitive to operational conditions. The best performance was obtained at HRT of 48 h and R of 3. The maximum removal efficiencies of COD, NH(4)(+)-N and phenols were 97.4%, 92.8% and 99.7%, with final concentrations in the effluent of 71 mg/L, 9.6 mg/L and 3 mg/L, respectively. Organics degradation and transformation were analyzed by GC/MS and it was found that anaerobic process played an important role in degradation of refractory compounds.

  19. Biotreatability of wastewater generated during machinery washing in a wood-based industry: COD, formaldehyde and nitrogen removal.

    Science.gov (United States)

    Kaczala, Fabio; Marques, Marcia; Hogland, William

    2010-12-01

    This paper describes biotreatability tests for treating a wastewater stream generated by wood-floor industries after cleaning and washing of machinery used to apply urea-formaldehyde resins onto wood-fiber boards. A biological system consisting of an anaerobic-intermittently aerated reactor in lab-scale was constructed. Since the investigated wastewater is intermittently generated, the system was designed to operate in batch mode. The treatment focused on removal of formaldehyde and COD, as well as the efficiency of nitrification-denitrification. The proposed cheap and relatively simple-to-operate biological system achieved COD and formaldehyde removal rates of 65+/-11% and 93+/-4% respectively. In spite of anaerobic ammonium removal and denitrification, the intermittently-aerated reactor showed poor performance for nitrification. Therefore, a better understanding of constraints for the process improvement is necessary. Regardless the constraints faced during the investigation, the proposed system can be considered feasible to partially reduce a great amount of biodegradable compounds in urea-formaldehyde-based wastewaters. However, to comply with strict threshold limits for industrial effluent discharges, the use of biological treatment combined with more advanced processes is needed to achieve a better quality of the final effluent.

  20. PENGGUNAAN LUMPUR AKTIF UNTUK MENURUNKAN KADAR Biological Oxygen Demand (BOD, Chemical Oxygen Demand (COD, dan LOGAM BERAT JENIS TIMBAL (Pb dan CADM IUM (Cd PADA LIMBAH CAIR PENCELUPAN INDUSTRI BATIK

    Directory of Open Access Journals (Sweden)

    RAFICHA RACHMA

    2015-06-01

    Full Text Available In the production process, batik dyeing industry use a lot of water and chemicals in the coloring or dyeing fabric dyeing wastewater batik. Batik dyeing waste industry typically have concentrations of chemical oxygen demand (COD and biological oxygen demand (BOD and heavy metals that exceed quality standards set by the government. In an effort to overcome the problems posed by wastewater, the wastewater treatment process must be done before the waste is discharged into aquatic environment. One of the biological wastewater treatment system that is able to reduce levels of contamination are industrial wastewater is activated sludge system. This research was conducted to determine the optimal time and time effectiveness of treatment with activated sludge to reduce levels of COD, BOD, and Pb in the batik industry wastewater. In this research using activated sludge by taking a fixed volume on sampling from hour o to hour 24 so as to produce organic compounds that remain much lower concentrations can result in COD, BOD, and Pb. This is because the longer the settling time of the volume of waste activated sludge with variable sampling and at the same time a decrease in the percentage levels of COD, BOD, and Pb greater. The results of this research found that activated sludge best influence in lowering the levels of COD, BOD, and Pb. This is due to the activity of microorganisms that have given nutrient and insufficient oxygen in aeration process with the longest time that the ability of the microbes in the sludge to oxidize organic materials with the highest effectiveness in the waste. After going through treatment with activated sludge showed that the optimal time of activated sludge treatment to decrease the levels of COD in wastewater dyeing batik industry is 12 hours, the reduced levels of BOD is 12 hours, and to decrease levels of Pb is 8 hours.

  1. Improving the simultaneous removal of chemical oxygen demand and terephthalic acid in a cross-flow aerobic sludge reactor by using response surface methodology.

    Science.gov (United States)

    Hu, Dong-Xue; Tian, Yu; Chen, Zhao-Bo; Ge, Hui; Cui, Yu-Bo; Ran, Chun-Qiu

    2015-01-01

    Central composite design and response surface methodology (RSM) were implemented to optimize the operational parameters for a cross-flow aerobic sludge reactor (CFASR) in remedying mixed printing and dyeing wastewater (MPDW). The individual and interactive effects of three variables, hydraulic retention time (HRT), pH and sludge loading rate (SLR), on chemical oxygen demand (COD) and terephthalic acid (TA) removal rates were evaluated. For HRT of 15.3-19.8 hours, pH of 7.2-8.1 and SLR of 0.4-0.6 kg chemical oxygen demand (COD) per kg mixed liquor suspended solids per day, COD and TA removal rates of the CFASR exceeded 85% and 90%, respectively. The check experiment revealed that the effluent from the optimized CFASR was stable below the limitation of 100 mg COD/L and the TA concentration decreased by 6.0% compared to the usual CFASR. The results verified that the RSM was useful for optimizing the operation parameters of the CFASR in remedying MPDW.

  2. Optimizing COD removal from greywater by photoelectro-persulfate process using Box-Behnken design: assessment of effluent quality and electrical energy consumption.

    Science.gov (United States)

    Ahmadi, Mehdi; Ghanbari, Farshid

    2016-10-01

    Greywater (GW) is a potential source for water reuse in various applications. However, GW treatment is still a vital issue in water reuse in cases of environmental standards and risk to public health. This study investigates optimization and modeling of a hybrid process for COD removal from GW. Persulfate (PS) was simultaneously activated by electrogenerated ferrous ion (EC) and UV to generate sulfate radical. Photoelectro-persulfate (PEPS) was optimized by Box-Behnken design and the effects of four variables (pH, PS dosage, current density, and electrolysis time) were evaluated on COD removal. The results and several coefficients showed that the obtained model was acceptable for predicting the COD removal. Moreover, under optimum conditions (pH = 6.9, PS = 8.8 mM, current density = 2.0 mA/cm(2), and 49.3 min electrolysis time), BOD5, turbidity, TSS, phosphate, and UV254 were effectively removed and COD and BOD5 values reached to discharge standards. Different configurations of the processes were assessed for COD removal. The order of COD removal efficiency followed: PS < Fe(II) < UV/PS ≤ Fe(II)/PS < Fe(II)/PS/UV < electrocoagulation ≤ electrocoagulation/UV < electro-PS < PEPS. The monitoring PS concentration during 60 min reaction time in the aforesaid processes indicated that PEPS could remarkably activate PS. The solution pH was also monitored and related results revealed that the presence of PS during the 10 min first time decreased pH value while production of hydroxide ion at cathode increased pH significantly. Finally, the contribution of electrochemical process in the electrical energy consumption was far less than that of photolysis process in hybrid PEPS process.

  3. Flow injection analysis of chemical oxygen demand (COD) by using a boron-doped diamond (BDD) electrode.

    Science.gov (United States)

    Yu, Hongbin; Ma, Chuanjun; Quan, Xie; Chen, Shuo; Zhao, Huimin

    2009-03-15

    A simple, environmentally friendly and continuous flow method was developed for the determination of COD based on a flow injection analysis (FIA) system, in which a BDD electrode was employed as the detecting element. The structure and the electrochemical behavior of BDD were investigated by a scanning electron microscope, Raman spectroscopy, and cyclic voltammetry, respectively. The results demonstrated thatthe high-quality BDD film prepared here was suitable to be used as an electrode, with which the COD measurement could be conducted. The effect of several important experimental parameters, such as applied potentials, pH, flow rates, and supporting electrolyte concentrations, on the analytical performance was investigated. Under optimized testing conditions, the proposed method was successfully applied in the COD analysis of synthetic samples. The linear range and the detection limit were 2-175 and 1 mg L(-1), respectively. In addition, the COD values determined by the proposed method compared well with those analyzed bythe conventional method as demonstrated by small relative errors.

  4. Reactor performance in terms of COD and nitrogen removal and bacterial community structure of a three-stage rotating bioelectrochemical contactor

    KAUST Repository

    Sayess, Rassil R.

    2013-02-01

    Integrating microbial fuel cell (MFC) into rotating biological contactor (RBC) creates an opportunity for enhanced removal of COD and nitrogen coupled with energy generation from wastewater. In this study, a three-stage rotating bioelectrochemical contactor (referred to as RBC-MFC unit) integrating MFC with RBC technology was constructed for simultaneous removal of carbonaceous and nitrogenous compounds and electricity generation from a synthetic medium containing acetate and ammonium. The performance of the RBC-MFC unit was compared to a control reactor (referred to as RBC unit) that was operated under the same conditions but without current generation (i.e. open-circuit mode). The effect of hydraulic loading rate (HLR) and COD/N ratio on the performance of the two units was investigated. At low (3.05 gCOD g-1N) and high COD/N ratio (6.64 gCOD g-1N), both units achieved almost similar COD and ammonia-nitrogen removal. However, the RBC-MFC unit achieved significantly higher denitrification and nitrogen removal compared to the RBC unit indicating improved denitrification at the cathode due to current flow. The average voltage under 1000 Ω external resistance ranged between 0.03 and 0.30 V and between 0.02 and 0.21 V for stages 1 and 2 of the RBC-MFC unit. Pyrosequencing analysis of bacterial 16S rRNA gene revealed high bacterial diversity at the anode and cathode of both units. Genera that play a role in nitrification (Nitrospira; Nitrosomonas), denitrification (Comamonas; Thauera) and electricity generation (Geobacter) were identified at the electrodes. Geobacter was only detected on the anode of the RBC-MFC unit. Nitrifiers and denitrifiers were more abundant in the RBC-MFC unit compared to the RBC unit and were largely present on the cathode of both units suggesting that most of the nitrogen removal occurred at the cathode. © 2012 Elsevier Ltd.

  5. Reactor performance in terms of COD and nitrogen removal and bacterial community structure of a three-stage rotating bioelectrochemical contactor.

    Science.gov (United States)

    Sayess, Rassil R; Saikaly, Pascal E; El-Fadel, Mutasem; Li, Dong; Semerjian, Lucy

    2013-02-01

    Integrating microbial fuel cell (MFC) into rotating biological contactor (RBC) creates an opportunity for enhanced removal of COD and nitrogen coupled with energy generation from wastewater. In this study, a three-stage rotating bioelectrochemical contactor (referred to as RBC-MFC unit) integrating MFC with RBC technology was constructed for simultaneous removal of carbonaceous and nitrogenous compounds and electricity generation from a synthetic medium containing acetate and ammonium. The performance of the RBC-MFC unit was compared to a control reactor (referred to as RBC unit) that was operated under the same conditions but without current generation (i.e. open-circuit mode). The effect of hydraulic loading rate (HLR) and COD/N ratio on the performance of the two units was investigated. At low (3.05 gCOD g⁻¹N) and high COD/N ratio (6.64 gCOD g⁻¹N), both units achieved almost similar COD and ammonia-nitrogen removal. However, the RBC-MFC unit achieved significantly higher denitrification and nitrogen removal compared to the RBC unit indicating improved denitrification at the cathode due to current flow. The average voltage under 1000 Ω external resistance ranged between 0.03 and 0.30 V and between 0.02 and 0.21 V for stages 1 and 2 of the RBC-MFC unit. Pyrosequencing analysis of bacterial 16S rRNA gene revealed high bacterial diversity at the anode and cathode of both units. Genera that play a role in nitrification (Nitrospira; Nitrosomonas), denitrification (Comamonas; Thauera) and electricity generation (Geobacter) were identified at the electrodes. Geobacter was only detected on the anode of the RBC-MFC unit. Nitrifiers and denitrifiers were more abundant in the RBC-MFC unit compared to the RBC unit and were largely present on the cathode of both units suggesting that most of the nitrogen removal occurred at the cathode.

  6. Comparison of Poly Aluminum Chloride and Chlorinated Cuprous for Chemical Oxygen Demand and Color Removal from Kashan Textile Industries Company Wastewater

    Directory of Open Access Journals (Sweden)

    Hoseindoost Gh.1 MSPH,

    2016-08-01

    Full Text Available Aims Textile wastewaters are the most important health and environmental problems in Kashan. This research was aimed to compare the poly aluminum chloride and chlorinated cuprous efficiency for removal of Chemical Oxygen Demand (COD and color from Kashan Textile Industries Company wastewater. Materials & Methods This experimental bench scale study in a batch system was conducted on 20 composed wastewater samples collected from Kashan Textile Industries Company raw wastewater. During 5 months, in the beginning of every week a day was selected randomly and in the day a composed sample was taken and studied. PAC at the doses of 10, 20, 30, 40 and 50mg.l-1 and chlorinated cuprous at the doses of 100, 200, 300, 400 and 500mg.l-1 were applied. The optimum pH also optimum concentration of PAC and chlorinated cuprous were determined using Jar test. The data was analyzed by SPSS 16 using descriptive statistics and Fisher Exact test. Findings The average concentration of COD in the raw textile wastewater was 2801.56±1398.29mg.l-1. The average COD concentration has been decreased to 1125.47±797.55mg.l-1. There was a significant difference between the effects of these two coagulants efficiency (p<0.05. The average COD removal efficiency for chlorinated cuprous and PAC was 58.52% and 72.56%, respectively. Also, the average color removal efficiency by chlorinated cuprous and PAC were 17.23 and 64.45%, respectively. Conclusion PAC is more efficient than chlorinated cuprous for both COD and color removal from KTIC wastewater.

  7. Co-Digestion of Palm Oil Mill Effluent and Refined Glycerin Wash Water for Chemical Oxygen Demand Removal and Methane Production

    Directory of Open Access Journals (Sweden)

    A. Sulaiman

    2009-01-01

    Full Text Available Problem statement: Refined Glycerin Wash Water (RGWW from the oleochemical industry contains high Chemical Oxygen Demand (COD and requires proper treatment before disposal. Unfortunately the wash water also contains high concentration of sodium chloride (NaCl that could cause inhibition to the normal biological treatment process. However, there is feasibility of co-digesting the RGWW and Palm Oil Mill Effluent (POME for its treatment and methane recovery. Approach: A large 500 m3 semi-commercial closed digester tank was used to study the effect of co-digesting POME and RGWW under mesophilic condition at different RGWW percentage. The digester performance in terms of COD removal efficiency and methane production rate and stability based on total Volatile Fatty Acids (VFA accumulation, Mixed Liquor Volatile Suspended Solid (MLVSS and pH were evaluated. Results: At 1.0% of RGWW co-digested, both COD removal efficiency and methane production rate showed satisfactory results with higher than 90% and 505 m3 day-1, respectively. However, once the percentage was increased to a maximum of 5.25%, COD removal efficiency remains high but the methane production rate reduced significantly down to 307 m3 day-1. At this stage, the digester was already unstable with high total VFA recorded of 913 mg L-1 and low cells concentration of 8.58 g L-1. This was probably due to the effect of plasmolysis on the methanogens at high concentration of NaCl in the digester of nearly 4000 mg L-1. Conclusion: Co-digesting of RGWW with high NaCl content and POME is satisfactory for COD removal but not for increasing the methane production.

  8. Nickel, manganese and copper removal by a mixed consortium of sulfate reducing bacteria at a high COD/sulfate ratio.

    Science.gov (United States)

    Barbosa, L P; Costa, P F; Bertolino, S M; Silva, J C C; Guerra-Sá, R; Leão, V A; Teixeira, M C

    2014-08-01

    The use of sulfate-reducing bacteria (SRB) in passive treatments of acidic effluents containing heavy metals has become an attractive alternative biotechnology. Treatment efficiency may be linked with the effluent conditions (pH and metal concentration) and also to the amount and nature of the organic substrate. Variations on organic substrate and sulfate ratios clearly interfere with the biological removal of this ion by mixed cultures of SRB. This study aimed to cultivate a mixed culture of SRB using different lactate concentrations at pH 7.0 in the presence of Ni, Mn and Cu. The highest sulfate removal efficiency obtained was 98 %, at a COD/sulfate ratio of 2.0. The organic acid analyses indicated an acetate accumulation as a consequence of lactate degradation. Different concentrations of metals were added to the system at neutral pH conditions. Cell proliferation and sulfate consumption in the presence of nickel (4, 20 and 50 mg l(-1)), manganese (1.5, 10 and 25 mg l(-1)) and copper (1.5, 10 and 25 mg l(-1)) were measured. The presence of metals interfered in the sulfate biological removal however the concentration of sulfide produced was high enough to remove over 90 % of the metals in the environment. The molecular characterization of the bacterial consortium based on dsrB gene sequencing indicated the presence of Desulfovibrio desulfuricans, Desulfomonas pigra and Desulfobulbus sp. The results here presented indicate that this SRB culture may be employed for mine effluent bioremediation due to its potential for removing sulfate and metals, simultaneously.

  9. Treatment of coal gasification wastewater by a two-continuous UASB system with step-feed for COD and phenols removal.

    Science.gov (United States)

    Wang, Wei; Han, Hongjun; Yuan, Min; Li, Huiqiang; Fang, Fang; Wang, Ke

    2011-05-01

    A two-continuous mesophilic (37 ± 2°C) UASB system with step-feed was investigated as an attractive optimization strategy for enhancing COD and total phenols removal of the system and improving aerobic biodegradability of real coal gasification wastewater. Through the step-feed period, the maximum removal efficiencies of COD and total phenols reached 55-60% and 58-63% respectively in the system, at an influent flow distribution ratio of 0.2 and influent COD concentration of 2500 mg/L; the corresponding efficiencies were at low levels of 45-50% and 43-50% respectively at total HRT of 48 h during the single-feed period. The maximum specific methanogenic activity and substrate utilization rate were 592 ± 16 mg COD-CH(4)/(g VSS d) and 89 ± 12 mg phenol/(g VSS d) during the step-feed operation. After the anaerobic digestion with step-feed, the aerobic effluent COD concentration decreased from 270 ± 9 to 215 ± 10 mg/L. The results suggested that step-feed enhanced the degradation of refractory organics in the second reactor.

  10. Biogas Production and Removal COD – BOD and TSS from Wastewater Industrial Alcohol (Vinasse by Modified UASB Bioreactor

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    Utami Isni

    2016-01-01

    Full Text Available Biogas production and decreased organic loading of vinasse using a modified UASB bioreactor has been done successfully. Vinasse is waste from the ethanol industry which contains COD: 9.360 mg / L , BOD : 4.013 mg/L, and TSS: 317.5 mg/L. The purpose of this research was to study the performance of bioreactors Upflow Anaerobic Sludge Blanket (UASB to decompose the vinasse into biogas or methane. UASB operating principle is to distribute wastewater in the bioreactor to flow upward through the sludge blanket by setting the hidrolic retention time (HRT. Four UASB bioreactor columns were used in this experiment wherein each with a capacity of 50 L in volume; 23 cm inside diameter, and 120 cm. The variations of hydraulic capacity followed the variations of HRT in the range of 72-36 hours. Modifications were carried out on the top of column UASB with the aim of preventing gas losses and increasing the flowrate of gas out from the top of the column. The results showed that HRT increased from 36 h to 72 h followed by an increase in COD removal efficiency of 55.64% to 66.81%; BOD5 from 67.85% to 74.58%; and TSS from 66.69% to 84.19%. The maximum volume of biogas produced was in the range of 5.826 L / day (42.89% methane to 7.930 L / day (methane 58.06%.

  11. THE EFFECT OF INFLUENT CONCENTRATION AND HYDRAULIC LOADING RATE (HLR TO BOD AND COD REMOVAL ON ARTIFICIAL DOMESTIC WASTEWATER TREATMENT (GREY WATER USING UASB REACTOR

    Directory of Open Access Journals (Sweden)

    Syafrudin Syafrudin

    2014-05-01

    Full Text Available Upflow anaerobic sludge blanket (UASB reactor is one of anaerobic biological treatment was develop in late 1970’s. UASB reactor is suitable for the tropic areas because it has a high temperature about 20°-30°C. Domestic wastewater is divided into two types, namely black water and grey water. But in this case used domestic grey water. Grey water is household wastewater from showers, sinks and kitchen. Grey water has a total 75% of the domestic wastewater volume. The research was conducted in laboratory scale. This study performed a variation of Hydraulic Loading Rate (HLR and the influent concentration. There were 25 reactors include 5 variations of influent concentration and 5 Hydraulic Loading Rate’s (HLR variation. The research could asses BOD5 and COD removal with treatment in UASB. Efficiency of BOD5 removal by varying the influent concentration and HLR was about 38%-75% and COD was about 40%-77%. The lower concentration could be increase efficiency BOD5 and COD removal. Influent concentration optimum occurred when middle concentration was about 840 mg/L COD and HLR optimum was 0,05 m3/m2/hour.

  12. Effect of carrier fill ratio on biofilm properties and performance of a hybrid fixed-film bioreactor treating coal gasification wastewater for the removal of COD, phenols and ammonia-nitrogen.

    Science.gov (United States)

    Rava, E; Chirwa, E

    2016-01-01

    The purpose of this study was to determine the effect different biofilm carrier filling ratios would have on biofilm morphology and activity and bacterial diversity in a hybrid fixed-film bioreactor treating high strength coal gasification wastewater (CGWW) for the removal of chemical oxygen demand (COD), phenols and ammonia-nitrogen. Results showed that a carrier fill of 70% formed a 'compact' biofilm, a 50% fill formed a 'rippling' biofilm and a 30% fill formed a 'porous' biofilm. The highest microbial activity was obtained with a 50% carrier fill supporting a relatively thin biofilm. The highest level of biofilm bound metals were aluminium, silicon, calcium and iron in the 'compact' biofilm; nitrogen, magnesium, chloride, sodium and potassium in the 'rippling' biofilm, and copper in the 'porous' biofilm. The bioreactor improved the quality of the CGWW by removing 49% and 78% of the COD and phenols, respectively. However, no significant amount of ammonia-nitrogen was removed since nitrification did not take place due to heterotrophic bacteria out-competing autotrophic nitrifying bacteria in the biofilm. The dominant heterotrophic genera identified for all three carrier filling ratios were Thauera, Pseudaminobacter, Pseudomonas and Diaphorobacter.

  13. Interference of H2 O2 on COD Test and Removal Method for Advanced Oxidation Process%高级氧化法中H2 O2对COD的测定影响及消除

    Institute of Scientific and Technical Information of China (English)

    郭亮; 焦纬洲; 刘有智; 许承骋; 刘文丽; 李静

    2014-01-01

    通过测定含不同 H2O2浓度的纯水体系及硝基苯类化合物水样体系的废水化学需氧量(COD),分析发现硝基苯类化合物水样中 H2 O2对 COD 的测量存在正干扰,且具有很好的线性关系。在不引入新的干扰前提下,探讨了相应的 H2 O2消除方法。结果表明,当水样中 H2O2浓度475 mg·L-1,COD 值为747.6 mg·L-1时,改变水样 pH 值为碱性有利于 H2O2的去除;添加二氧化锰催化剂虽然能在较短时间内去除 H2 O2,但可能引入新的干扰物;添加过氧化氢酶在不引入新的干扰情况下可快速去除 H2 O2。当反应时间3 min,分别调节水样 pH 为12、添加二氧化锰、添加过氧化氢酶,水样中 H2 O2去除率为1.2%、45.6%、100%。在相同酶量下处理含不同浓度 H2 O2的水样,H2 O2均可在短时间内被除净。分析表明,添加过氧化氢酶可为快速、高效消除废水中未知浓度 H2O2对 CODCr测定的影响提供一条新的途径。%The chemical oxygen demand( COD)for pure water and nitrobenzene waste water sample containing different content of H2 O2 was measured and the linear interference of H2 O2 concentration on COD test was studied. It shows that with increase of the H2 O2 ,the COD increases. Without new interference,the ways to suppress interference of H2 O2 on COD test were discussed including pH value,manganese dioxide catalyst,and catalase. Results show that the catalase eliminates the influence of H2O2on COD determination effectively,and the alkaline environment is in favor of removing the H2O2 to some extent,and manganese di-oxide catalyst can remove H2 O2 in short time but it may introduce new interferences. When the reaction time is 3 min,by adjus-ing initial liquid pH value of 12,adding manganese dioxide catalyst and catalase,respectively,the H2O2 removal rate can reach 1.2%,45.6% and 100%,indicating that catalase can conveniently remove H2O2 with unknown concentration

  14. Wastewater treatment in molasses-based alcohol distilleries for COD and color removal: a review.

    Science.gov (United States)

    Satyawali, Y; Balakrishnan, M

    2008-02-01

    Molasses-based distilleries are one of the most polluting industries generating large volumes of high strength wastewater. Different processes covering anaerobic, aerobic as well as physico-chemical methods have been employed to treat this effluent. Anaerobic treatment is the most attractive primary treatment due to over 80% BOD removal combined with energy recovery in the form of biogas. Further treatment to reduce residual organic load and color includes various: (i) biological methods employing different fungi, bacteria and algae, and (ii) physico-chemical methods such as adsorption, coagulation/precipitation, oxidation and membrane filtration. This work presents a review of the existing status and advances in biological and physico-chemical methods applied to the treatment of molasses-based distillery wastewater. Both laboratory and pilot/industrial studies have been considered. Furthermore, limitations in the existing processes have been summarized and potential areas for further investigations have been discussed.

  15. Ability of the aquatic fern Azolla to remove chemical oxygen demand and polyphenols from olive mill wastewater

    Directory of Open Access Journals (Sweden)

    Sacchi, Angelo

    2007-03-01

    Full Text Available We investigated the biofiltration ability of the aquatic fern Azolla to remove polyphenols and chemical oxygen demand (COD from olive mill wastewater (OMWw collected from the traditional (TS and continuous (CS extraction systems. Azolla biomass was packed into five sequential Imhoff cones and five sequential columns. In both experiments, the filtrates collected from the 5th biofilter showed a decrease in polyphenol contents: from 7650 mg l–1 to 3610 mg l–1 in TS OMWw and from 3852 mg l–1 to 1351 mg l–1 in CS OMWw. The COD contents decreased from 110200 mg L–1 to 52400 mg L–1 in TS OMWw and from 41600 mg L–1 to 2300 mg L–1 in CS OMWw. A 5:1 OMWw to Azolla-fresh-weight ratio was optimal for both polyphenol and COD removal. The biofiltration ability of alfalfa was compared with that of Azolla, but the treatment with alfalfa did not result in the reduction of COD or polyphenols.La eficacia del helecho de agua azolla para eliminar polifenoles y reducir la demanda química de oxígeno (DQO de los alpechines obtenidos en el proceso de obtención tradicional y continuo del aceite de oliva, fue investigado mediante ensayos de filtración. Cinco conos secuenciales de Imhoff y cinco columnas secuenciales se rellenaron de biomasa de Azolla. En ambos experimentos, el filtrado procedente de la quinta extracción mostró una disminución en el contenido de polifenoles de 7650 mg L–1 a 3610 mg L–1en el alpechín obtenido mediante el sistema tradicional y de 3852 mg L–1 a 1351 mg L–1en el alpechín del sistema continuo. La demanda química de oxígeno del alpechín del sistema tradicional disminuyó de 110200 mg L–1 a 52400 mg L–1 en y de 41600 mg L–1a 2300 mg L–1en el procedente del sistema continuo. Una proporción en peso 5:1 de alpechín: Azolla fue la óptima tanto para la reducción de los polifenoles como para la de la DQO. La eficiencia del tratamiento biológico con alfalfa se comparó con la obtenida con Azolla. Los

  16. Development of variable pathlength UV-vis spectroscopy combined with partial-least-squares regression for wastewater chemical oxygen demand (COD) monitoring.

    Science.gov (United States)

    Chen, Baisheng; Wu, Huanan; Li, Sam Fong Yau

    2014-03-01

    To overcome the challenging task to select an appropriate pathlength for wastewater chemical oxygen demand (COD) monitoring with high accuracy by UV-vis spectroscopy in wastewater treatment process, a variable pathlength approach combined with partial-least squares regression (PLSR) was developed in this study. Two new strategies were proposed to extract relevant information of UV-vis spectral data from variable pathlength measurements. The first strategy was by data fusion with two data fusion levels: low-level data fusion (LLDF) and mid-level data fusion (MLDF). Predictive accuracy was found to improve, indicated by the lower root-mean-square errors of prediction (RMSEP) compared with those obtained for single pathlength measurements. Both fusion levels were found to deliver very robust PLSR models with residual predictive deviations (RPD) greater than 3 (i.e. 3.22 and 3.29, respectively). The second strategy involved calculating the slopes of absorbance against pathlength at each wavelength to generate slope-derived spectra. Without the requirement to select the optimal pathlength, the predictive accuracy (RMSEP) was improved by 20-43% as compared to single pathlength spectroscopy. Comparing to nine-factor models from fusion strategy, the PLSR model from slope-derived spectroscopy was found to be more parsimonious with only five factors and more robust with residual predictive deviation (RPD) of 3.72. It also offered excellent correlation of predicted and measured COD values with R(2) of 0.936. In sum, variable pathlength spectroscopy with the two proposed data analysis strategies proved to be successful in enhancing prediction performance of COD in wastewater and showed high potential to be applied in on-line water quality monitoring.

  17. Removal of color and chemical oxygen demand using a coupled coagulation-electrocoagulation-ozone treatment of industrial wastewater that contains offset printing dyes

    Energy Technology Data Exchange (ETDEWEB)

    Roa M, G.; Barrera D, C.; Balderas H, P.; Zaldumbide O, F. [Centro Conjunto de Investigacion en Quimica Sustentable UAEM-UNAM, Km 14.5 Carretera Toluca-Atlacomulco, 50200 San Cayetano-Toluca, Estado de Mexico (Mexico); Reyes P, H. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon y Paseo Tollocan s/n, 50120 Toluca, Estado de Mexico (Mexico); Bilyeu, B., E-mail: groam@uaemex.mx [Xavier University of Louisiana, Department of Chemistry, 1 Drexel Drive, New Orleans, LA 70125 (United States)

    2014-07-01

    Industrial offset printing processes generate wastewater with highly colored obtaining values of 5 x 10{sup 6}Pt-Co units and great values of chemical oxygen demand (COD) 5.3 x 10{sup -5} mg L{sup -1}. Thus, conventional technologies such as biologicals treatment fail in reaching the discharge limits. In this research, a sequential treatment was applied: coagulation with aluminum hydroxychloride (AHC), electrocoagulation with Al anodes and finally ozonation. Optimal conditions are found when adding 20 mg L{sup -1} AHC, followed by electrocoagulation at 4 A for 50 min, and finally alkaline ozonation for 15 min, resulting in an overall color removal of 99.99% color and 99.35 COD. The sludge generated by the coagulation process was analyzed by scanning electron microscopy and energy dispersive X-ray (EDX) microanalysis. (Author)

  18. Development of A Novel Methode for COD (Chemical Oxygen Demand Measurement based onPhotoelectrochemical Cell: Characterization of TiO2/ITO Film Working Electrode

    Directory of Open Access Journals (Sweden)

    Y.K. Krisnandi

    2009-04-01

    Full Text Available Nanosize TiO2 film,immobilized on an ITO (Indium Tin Oxide glass, was successfully fabricated. The film was prepared by a dip coatingtechnique in a hydrothermal sol-gel system and subjected to a heat treatment at 100°C up to 450°C. Characterization ofthe film by XRD, AFM, BET methods revealed the occurrence of anatase form and 9.64 nm in crystallite size; havingthree dimensional profile and roughness with height of typically 9.8 nm; and surface area of 58.21 m2/g. The film thenwas employed as a working electrode in a photo electrochemical system (PES. This PES generated a photocurrent thatproportional to the organic chemical concentration in the water sample. Integration of the photocurrent versus timegives a charge (Q that represent the event of complete mineralization of organic chemical in the TiO2 surface and canbe correlated to the Chemical Oxygen Demand (COD of measured water. This system has a potential to be developedfor a novel COD sensor.

  19. COD, nutrient removal and disinfection efficiency of a combined subsurface and surface flow constructed wetland: A case study.

    Science.gov (United States)

    Sartori, Laura; Canobbio, Sergio; Fornaroli, Riccardo; Cabrini, Riccardo; Marazzi, Francesca; Mezzanotte, Valeria

    2016-01-01

    A constructed wetland system composed of a subsurface flow wetland, a surface flow wetland and a facultative pond was studied from July 2008 until May 2012. It was created to treat the domestic sewage produced by a hamlet of 150 inhabitants. Monthly physicochemical and microbiological analyses were carried out in order to evaluate the removal efficiency of each stage of the process and of the total treatment system. Pair-wise Student's t-tests showed that the mean removal of each considered parameter was significantly different (α = 0.05) between the various treatment phases. Two-way ANOVA and Tukey's HSD tests were used to find significant differences between wetland types and seasons in the removal efficiency of the considered water quality parameters. Significant differences in percent removal efficiency between the treatment phases were observed for total phosphorus, total nitrogen, ammonia nitrogen and organic load (expressed as Chemical Oxygen Demand). In general, the wastewater treatment was carried by the sub-superficial flow phase mainly, both in growing season and in quiescence season. Escherichia coli removal ranged from 98% in quiescence season to >99% in growing season (approximately 2-3 orders of magnitude). The inactivation of fecal bacteria was not influenced by the season, but only by the treatment phase.

  20. Simultaneous efficient removal of high-strength ammonia nitrogen and chemical oxygen demand from landfill leachate by using an extremely high ammonia nitrogen-resistant strain.

    Science.gov (United States)

    Yu, Dahai; Yang, Jiyu; Fang, Xuexun; Ren, Hejun

    2015-01-01

    Bioaugmentation is a promising technology for pollutant elimination from stressed environments, and it would provide an efficient way to solve challenges in traditional biotreatment of wastewater with high strength of ammonia nitrogen (NH4(+)-N). A high NH4(+)-N-resistant bacteria strain, identified as Bacillus cereus (Jlu BC), was domesticated and isolated from the bacteria consortium in landfill leachate. Jlu BC could survive in 100 g/L NH4(+)-N environment, which indicated its extremely high NH4(+)-N tolerance than the stains found before. Jlu BC was employed in the bioaugmented system to remove high strength of NH4(+)-N from landfill leachate, and to increase the removal efficiency, response surface methodology (RSM) was used for optimizing bioaugmentation degradation conditions. At the optimum condition (initial pH 7.33, 4.14 days, initial chemical oxygen demand [COD] concentration [18,000 mg/L], 3.5 mL inoculated domesticated bacteria strain, 0.3 mg/mL phosphorus supplement, 30 °C, and 170 rpm), 94.74 ± 3.8% removal rate of NH4(+)-N was obtained, and the experiment data corresponded well with the predicted removal rate of the RSM models (95.50%). Furthermore, COD removal rate of 81.94 ± 1.4% was obtained simultaneously. The results presented are promising, and the screened strain would be of great practical importance in mature landfill leachate and other NH4(+)-N enrichment wastewater pollution control.

  1. Colour and COD removal of disperse dye solution by a novel coagulant: application of statistical design for the optimization and regression analysis.

    Science.gov (United States)

    Anouzla, Abdelkader; Abrouki, Younes; Souabi, Salah; Safi, Mohammed; Rhbal, Hicham

    2009-07-30

    The investigation presented here focussed on the steel industrial wastewater (SIWW) FeCl(3) rich as an original coagulant to remove the synthetic textile wastewater. Response surface methodology was used to study the cumulative effect of the various parameters namely, coagulant dosage, initial pH of dye solution, dye concentration and to optimize the process conditions for the decolourization and COD reduction of disperse blue 79 solution. For obtaining the mutual interaction between the variables and optimizing these variables, a 2(3) full factorial central composite rotatable design using response surface methodology was employed. The efficiencies of decolourization and COD reduction for disperse blue 79 solution were accomplished at optimum conditions as 99% and 94%, respectively.

  2. Role of H2O2 in the fluctuating patterns of COD (chemical oxygen demand) during the treatment of palm oil mill effluent (POME) using pilot scale triple frequency ultrasound cavitation reactor.

    Science.gov (United States)

    Manickam, Sivakumar; Abidin, Norhaida binti Zainal; Parthasarathy, Shridharan; Alzorqi, Ibrahim; Ng, Ern Huay; Tiong, Timm Joyce; Gomes, Rachel L; Ali, Asgar

    2014-07-01

    Palm oil mill effluent (POME) is a highly contaminating wastewater due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD). Conventional treatment methods require longer residence time (10-15 days) and higher operating cost. Owing to this, finding a suitable and efficient method for the treatment of POME is crucial. In this investigation, ultrasound cavitation technology has been used as an alternative technique to treat POME. Cavitation is the phenomenon of formation, growth and collapse of bubbles in a liquid. The end process of collapse leads to intense conditions of temperature and pressure and shock waves which assist various physical and chemical transformations. Two different ultrasound systems i.e. ultrasonic bath (37 kHz) and a hexagonal triple frequency ultrasonic reactor (28, 40 and 70 kHz) of 15 L have been used. The results showed a fluctuating COD pattern (in between 45,000 and 60,000 mg/L) while using ultrasound bath alone, whereas a non-fluctuating COD pattern with a final COD of 27,000 mg/L was achieved when hydrogen peroxide was introduced. Similarly for the triple frequency ultrasound reactor, coupling all the three frequencies resulted into a final COD of 41,300 mg/L compared to any other individual or combination of two frequencies. With the possibility of larger and continuous ultrasonic cavitational reactors, it is believed that this could be a promising and a fruitful green process engineering technique for the treatment of POME.

  3. Application of Photo-Fenton Process for COD Removal from Wastewater Produced from Surfactant-Washed  Oil-Contaminated (TPH Soils

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Mehrasbi

    2012-10-01

    Full Text Available Backgrounds and Objectives: The base structure of total petroleum hydrocarbons (TPH is made of hydrogen and carbon. Widespread use, improper disposal and accidental spills of this compounds lead to long term remaining of contaminations such as organic solvents and poly aromatic hydrocarbons (PAHs in the soil and groundwater resources, resulting in critical environmental issues. In this study, an oil-contaminated soil was washed using Tween 80 surfactant and the application of photo-Fenton process (UV/Fe2+/H2O2 for treatment of the produced wastewater was evaluated. Materials and Methods: Tween 80 is a yellow liquid with high viscosity and soluble in water. In order to determine of the photo-Fenton process efficiency, we studied effective variables including Fe concentration, pH, H2O2 concentration, and irradiation time. The UV irradiation source was a medium-pressure mercury vapor lamp (400 w vertically immersed in the solution within 2L volume glass cylindrical reactor.Results: The results showed that efficiency of COD removal depends on the initial Fe concentration, pH, H2O2 concentration and irradiation time. Under optimum conditions, (Fe: 0.1mM, H2O2: 0.43 mM, pH: 3 and UV light irradiation time: 2 hours the removal efficiency of COD was 67.3%. pH plays a crucial role in the photo-Fenton process such that the removal efficiency increased with decreasing of pH. Conclusion: According to the results of this study, under acidic condition, this process is an efficient method for COD removal from the wastewater studied.

  4. Effect of feed strategy and cod/sulfate ratio on the removal of sulfate in an AnSBBR with recirculation of the liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Archilha, N. C.; Canto, C. S. A.; Ratusznei, S. M.; Rodrigues, J. A.D.; Zaiat, M.; Foresti, E.

    2009-07-01

    The objective of this work was to analyze the effect of the interaction between feed strategy and COD/[SO{sub 4}{sup 2}] ratio on the efficiency of sulfate removal from a synthetic wastewater. To this end, an anaerobic sequencing batch reactor, with recirculation of the liquid phase, containing immobilized biomass on polyurethane foam (AnSBBR) was used. The reactor, with a working volume of 2.7 L, treated 2.0 L synthetic wastewater in 8-h cycles. The system was inoculated with anaerobic biomass from a UASB reactor and was maintained at 30{+-} 1 degree centigrade in a chamber with temperature control. (Author)

  5. Cr(VI) and COD removal from landfill leachate by polyculture constructed wetland at a pilot scale.

    Science.gov (United States)

    Madera-Parra, C A; Peña, M R; Peña, E J; Lens, P N L

    2015-09-01

    Four subsurface horizontal-flow constructed wetlands (CWs) at a pilot scale planted with a polyculture of the tropical plants Gynerium sagittatum (Gs), Colocasia esculenta (Ce) and Heliconia psittacorum (He) were evaluated for 7 months. The CW cells with an area of 17.94 m(2) and 0.60 m (h) each and 0.5 m of gravel were operated at continuous gravity flow (Q = 0.5 m(3) day(-1)) and a theoretical HRT of 7 days each and treating landfill leachate for the removal of filtered chemical oxygen demand (CODf), BOD5, TKN, NH4 (+), NO3 (-), PO4 (3-)-P and Cr(VI). Three CWs were divided into three sections, and each section (5.98 m(2)) was seeded with 36 cuttings of each species (plant density of six cuttings per square metre). The other unit was planted randomly. The final distributions of plants in the bioreactors were as follows: CW I (He-Ce-Gs), CW II (randomly), CW III (Ce-Gs-He) and CW IV (Gs-He-Ce). The units received effluent from a high-rate anaerobic pond (BLAAT®). The results show a slightly alkaline and anoxic environment in the solid-liquid matrix (pH = 8.0; 0.5-2 mg L(-1) dissolved oxygen (DO)). CODf removal was 67 %, BOD5 80 %, and TKN and NH4 (+) 50-57 %; NO3 (-) effluents were slightly higher than the influent, PO4 (3-)-P (38 %) and Cr(VI) between 50 and 58 %. CW IV gave the best performance, indicating that plant distribution may affect the removal capacity of the bioreactors. He and Gs were the plants exhibiting a translocation factor (TF) of Cr(VI) >1. The evaluated plants demonstrated their suitability for phytoremediation of landfill leachate, and all of them can be categorized as Cr(VI) accumulators. The CWs also showed that they could be a low-cost operation as a secondary system for treatment of intermediated landfill leachate (LL).

  6. Performance of a stratified sand filter in removal of chemical oxygen demand, total suspended solids and ammonia nitrogen from high-strength wastewaters.

    Science.gov (United States)

    Healy, M G; Rodgers, M; Mulqueen, J

    2007-06-01

    A stratified sand filter column, operated in recirculation mode and treating synthetic effluent resembling high-strength dairy wastewaters was studied over a 342-d duration. The aim of this paper was to examine the organic, total suspended solids (TSS) and nutrient removal rates of the sand filter, operated in recirculation mode, under incrementally increasing hydraulic and organic loading rates and to propose a field filter-sizing criterion. Best performance was obtained at a system hydraulic loading rate of 10 L m(-2) d(-1); a higher system hydraulic loading rate (of 13.4 L m(-2) d(-1)) caused surface ponding. The system hydraulic loading rate of 10 L m(-2) d(-1) gave a filter chemical oxygen demand (COD), TSS, and total kjeldahl nitrogen (TKN) loading rate of 14, 3.7, and 2.1 g m(-2) d(-1), respectively, and produced consistent COD and TSS removals of greater than 99%, and an effluent NO(3)-N concentration of 42 mg L(-1) (accounting for an 86% reduction in total nitrogen (Tot-N)). As the proportional surface area requirement for the sand filter described in this study is less than the recommended surface area requirement of a free-water surface (FWS) wetland treating an effluent of similar quality, it could provide an economic and sustainable alternative to conventional wetland treatment.

  7. The Static Research on Adsorption Characteristics and Removal Efficiency of COD by Different Zeolite Substrates in Biogas Slurry%不同沸石材料对沼液中 COD 静态吸附去除的研究

    Institute of Scientific and Technical Information of China (English)

    邢赜; 陈玉成; 熊佰炼; 陈瑶; 常琛

    2013-01-01

    The COD was high in concentric biogas slurry which contained plenty of organic nutrients .To search for excel-lent COD adsorption substrates ,both the thermo-dynamics adsorption-desorption characteristics of COD by five common substrates (Natural zeolite(TRF),microwave-sodium chloride modified zeolite(WLF),cetylpyridinium Bromize modified zeolite(CPBF),micro-sized zeolite(WF)and submicro-sized zeolite(YWF)synthesized from coal fly ash) were illustra-ted in laboratory .The results indicated that CPBF had higher adsorption capacities and velocities of COD and lower COD desorption efficiencie than other zeolite substrates which means it could be excellent COD adsorption substrate .%集中型沼液由于含有较丰富的有机营养成分, COD 负荷较高。为了寻找高效 COD 吸附基质,以天然斜发沸石( TRF )、微波与氯化钠联合改性沸石( WLF )、CPB 改性沸石( CPBF )、微米级( WF )以及亚微米级( YWF )两种粉煤灰合成沸石为研究对象,对沼液COD 的热力学吸附解吸进行研究。结果表明,与其他4种沸石材料相比, CPBF 具有更高的 COD 吸附量和吸附速率以及更低的解吸率,因此具有较大的沼液 COD 吸附优势,是优良的吸附材料。

  8. High removal of chemical and biochemical oxygen demand from tequila vinasses by using physicochemical and biological methods.

    Science.gov (United States)

    Retes-Pruneda, Jose Luis; Davila-Vazquez, Gustavo; Medina-Ramírez, Iliana; Chavez-Vela, Norma Angelica; Lozano-Alvarez, Juan Antonio; Alatriste-Mondragon, Felipe; Jauregui-Rincon, Juan

    2014-08-01

    The goal of this research is to find a more effective treatment for tequila vinasses (TVs) with potential industrial application in order to comply with the Mexican environmental regulations. TVs are characterized by their high content of solids, high values of biochemical oxygen demand (BODs), chemical oxygen demand (COD), low pH and intense colour; thus, disposal of untreated TVs severely impacts the environment. Physicochemical and biological treatments, and a combination of both, were probed on the remediation of TVs. The use of alginate for the physicochemical treatment of TVs reduced BOD5 and COD values by 70.6% and 14.2%, respectively. Twenty white-rot fungi (WRF) strains were tested in TV-based solid media. Pleurotus ostreatus 7992 and Trametes trogii 8154 were selected due to their ability to grow on TV-based solid media. Ligninolytic enzymes' production was observed in liquid cultures of both fungi. Using the selected WRF for TVs' bioremediation, both COD and BOD5 were reduced by 88.7% and 89.7%, respectively. Applying sequential physicochemical and biological treatments, BOD5 and COD were reduced by 91.6% and 93.1%, respectively. Results showed that alginate and selected WRF have potential for the industrial treatment of TVs.

  9. Decolorization and removal of cod and bodfrom raw and biotreated textile dye bath effluent through advanced oxidation processes (AOPS

    Directory of Open Access Journals (Sweden)

    A. Muhammad

    2008-09-01

    Full Text Available In this paper, a comparative study of the treatment of raw and biotreated (upflow anaerobic sludge blanket, UASB textile dye bath effluent using advanced oxidation processes (AOPs is presented. The AOPs applied on raw and biotreated textile dye bath effluent, after characterization in terms of COD, colour, BOD and pH, were ozone, UV, UV/H2O2 and photo-Fenton. The decolorization of raw dye bath effluent was 58% in the case of ozonation. However it was 98% in the case of biotreated dye bath effluent when exposed to UV/H2O2. It is, therefore, suggested that a combination of biotreatment and AOPs be adopted to decolorize dye bath effluent in order to make the process more viable and effective. Biodegradability was also improved by applying AOPs after biotreatment of dye bath effluent.

  10. [Influence of substrate COD on methane production in single-chambered microbial electrolysis cell].

    Science.gov (United States)

    Teng, Wen-Kai; Liu, Guang-Li; Luo, Hai-Ping; Zhang, Ren-Duo; Fu, Shi-Yu

    2015-03-01

    The chemical oxygen demand (COD) of substrate can affect the microbial activity of both anode and cathode biofilm in the single-chamber methanogenic microbial electrolysis cell (MEC). In order to investigate the effect of COD on the performance of MEC, a single chamber MEC was constructed with biocathode. With the change of initial concentration of COD (700, 1 000 and 1 350 mg x L(-1)), the methane production rate, COD removal and energy efficiency in the MEC were examined under different applied voltages. The results showed that the methane production rate and COD removal increased with the increasing COD. With the applied voltage changing from 0.3 to 0.7 V, the methane production rate increased at the COD of 700 mg x L(-1), while it increased at first and then decreased at the COD of 1000 mg x L(-1) and 1350 mg x L(-1). A similar trend was observed for the COD removal. The cathode potential reached the minimum (- 0.694 ± 0.001) V as the applied voltage was 0.5 V, which therefore facilitated the growth of methanogenic bacteria and improved the methane production rate and energy efficiency of the MEC. The maximum energy income was 0.44 kJ ± 0.09 kJ (1450 kJ x m(-3)) in the MEC, which was obtained at the initial COD of 1000 mg x L(-1) and the applied voltage of 0.5 V. Methanogenic MECs could be used for the treatment of wastewaters containing low organic concentrations to achieve positive energy production, which might provide a new method to recover energy from low-strength domestic wastewater.

  11. Development of biofilm on geotextile in a new multi-zone wastewater treatment system for simultaneous removal of COD, nitrogen and phosphorus.

    Science.gov (United States)

    Alimahmoodi, Mahmood; Yerushalmi, Laleh; Mulligan, Catherine N

    2012-03-01

    This study investigated the formation and evolution of biofilm on a fixed cylindrical structure wrapped in geotextile, in a multi-zone wastewater treatment system called BioCAST. The organic, nitrogen and phosphorus loading rates of (OLR) 0.95-1.86 g COD/(m(3)d), (NLR) 0.02-0.08 kg N/(m(3)d), and (PLR) 0.014-0.02 kg P/(m(3)d), were applied. The results demonstrated high removal efficiencies of carbon, nitrogen and phosphorus, reaching 98.9%, 98.3% and 94.1%, respectively, after 250 d of operation. The biofilm biomass showed a fast formation (reaching 54.2g/L) and maximum phosphorus content of about 7% (dry basis). Biofilm demonstrated the ability to remove phosphorus, and its characteristics correlated with nitrogen and phosphorus removal rates. The geotextile material with filamentous structure causing rapid attachment and formation of biofilm can solve many problems encountered in conventional attached-growth wastewater treatment systems such as slow start-up, low reactor biomass content and low capacity to handle high organic loading rates.

  12. Hydrogen and lipid production from starch wastewater by co-culture of anaerobic sludge and oleaginous microalgae with simultaneous COD, nitrogen and phosphorus removal.

    Science.gov (United States)

    Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Ren, Nanqi

    2015-11-15

    Anaerobic sludge (AS) and microalgae were co-cultured to enhance the energy conversion and nutrients removal from starch wastewater. Mixed ratio, starch concentration and initial pH played critical roles on the hydrogen and lipid production of the co-culture system. The maximum hydrogen production of 1508.3 mL L(-1) and total lipid concentration of 0.36 g L(-1) were obtained under the optimized mixed ratio (algae:AS) of 30:1, starch concentration of 6 g L(-1) and initial pH of 8. The main soluble metabolites in dark fermentation were acetate and butyrate, most of which can be consumed in co-cultivation. When sweet potato starch wastewater was used as the substrate, the highest COD, TN and TP removal and energy conversion efficiencies reached 80.5%, 88.7%, 80.1% and 34.2%, which were 176%, 178%, 200% and 119% higher than that of the control group (dark fermentation), respectively. This research provided a novel approach and achieved efficient simultaneous energy recovery and nutrients removal from starch wastewater by the co-culture system.

  13. Performance of metal compound on thermolysis and electrolysis on sugar industries waste water treatment: COD and color removal with sludge analysis (batch-experiment)

    Science.gov (United States)

    Sahu, Omprakash

    2016-06-01

    The sugar cane industry is one of the most water demanding industries. Sugar industries consume and generate excess amount of water. The generated water contains organic compounds, which would cause pollution. The aim of this research work is to study the effectiveness of metal compound for treatment of sugar industry waste water by thermolysis and electrolysis process. The result shows ferrous metal catalyst shows 80 and 85 % chemical oxygen demand and color removal at pH 6, optimum mass loading 4 kg/m3, treatment temperature 85 °C and treatment time 9 h. When ferrous material was used as electrode, maximum 81 % chemical oxygen demand and 84 % color removal at pH 6, current density 156 Am-2, treatment time 120 min and anode consumption 0.7 g for 1.5 L wastewater were obtained.

  14. Kinetics of para-nitrophenol and chemical oxygen demand removal from synthetic wastewater in an anaerobic migrating blanket reactor.

    Science.gov (United States)

    Kuşçu, Ozlem Selçuk; Sponza, Delia Teresa

    2009-01-30

    A laboratory scale anaerobic migrating blanket reactor (AMBR) was operated at different HRTs (1-10.38 days) in order to determine the para-nitrophenol (p-NP) and COD removal kinetic constants. The reactor was fed with 40 mg L(-1)p-NP and 3000 mg L(-1) glucose-COD. Modified Stover-Kincannon and Grau second-order kinetic models were applied to the experimental data. The predicted p-NP and COD concentrations were calculated using the kinetic constants. It was found that these data were in better agreement with the observed ones in the modified Stover-Kincannon compared to Grau second-order model. The kinetic constants calculated according to Stover-Kincannon model are as follows: the saturation value constant (K(B)) and maximum utilization rate constants (R(max)) were found as 31.55 g CODL(-1)day(-1), 29.49 g CODL(-1)day(-1) for COD removal and 0.428 g p-NPL(-1)day(-1), 0.407 g p-NPL(-1)day(-1) for p-NP removal, respectively (R(2)=1). The values of (a) and (b) were found to be 0.096 day and 1.071 (dimensionless) with high correlation coefficients of R(2)=0.85 for COD removal. Kinetic constants for specific gas production rate were evaluated using modified Stover-Kincannon, Van der Meer and Heerrtjes and Chen and Hasminoto models. It was shown that Stover-Kincannon model is more appropriate for calculating the effluent COD, p-NP concentrations in AMBR compared to the other models. The maximum specific biogas production rate, G(max), and proportionality constant, G(B), were found to be 1666.7 mL L(-1) day(-1) and 2.83 (dimensionless), respectively in modified Stover-Kincannon gas model. The bacteria had low Haldane inhibition constants (K(ID)=14 and 23 mg L(-1)) for p-NP concentrations higher than 40 mg L(-1) while the half velocity constant (K(s)) increased from 10 to 60 and 118 mg L(-1) with increasing p-NP concentrations from 40 to 85 and 125 mg L(-1).

  15. Evaluation of autotrophic and heterotrophic processes in biofilm reactors used for removal of sulphide, nitrate and COD.

    Science.gov (United States)

    Tang, Kimberley; An, Shijie; Nemati, Mehdi

    2010-11-01

    Microbial cultures originated from an oil reservoir were used in three biofilm reactors and effects of sulphide and nitrate loading rates and molar loading ratio on the removal of sulphide, nitrate and acetate, and composition of end products were investigated. Application of biofilms improved sulphide and nitrate removal rates significantly when compared with freely suspended cells. Maximum sulphide and nitrate removal rates under autotrophic conditions were 30.0 and 24.4 mM h(-1), respectively (residence time: 0.5h). Oxidation of acetate occurred only at nitrate to sulphide molar loading ratios around 0.7 or higher when nitrate was present at levels higher than that required for oxidation of sulphide to sulphur. Conversion of sulphide to sulphate increased from 0% to 66% as nitrate to sulphide molar loading ratio was increased from 0.34 to 3.98. The highest nitrate and acetate removal rates in the bioreactor operated under heterotrophic conditions were 183.2 and 88.0 mM h(-1), respectively (residence time: 0.8h).

  16. Effects of COD/N ratio and DO concentration on simultaneous nitrification and denitrification in an airlift internal circulation membrane bioreactor

    Institute of Scientific and Technical Information of China (English)

    MENG Qingjuan; YANG Fenglin; LIU Lifen; MENG Fangang

    2008-01-01

    In this article, the effects of chemical oxygen demand, nitrogen (COD/N) ratio (4.90, 9.59, and 14.44), and dissolved oxygen concentration (DO) (0.5, 1.0, 1.5, and 3.0 mg/L) on simultaneous nitrification and denitrification (SND) were investigated using an airlift internal circulation membrane bioreactor (AIC-MBR) with synthetic wastewater. The results showed that the COD efficiencies were consistently greater than 90% regardless of changes in the COD/N ratio. At the COD/N ratio of 4.90 and 9.59, the system nitrogen removal efficiency became higher than 70%. However, the nitrogen removal efficiency decreased to less than 50%, as the COD/N ratio shifted to 14.44. When the operating DO concentration was maintained at 1.0 mg/L in AIC-MBR, a satisfying SND was achieved. Either low or high DO concentration could restrain SND.

  17. Characterization of a novel micro-pressure swirl reactor for removal of chemical oxygen demand and total nitrogen from domestic wastewater at low temperature.

    Science.gov (United States)

    Ren, Qingkai; Yu, Yang; Zhu, Suiyi; Bian, Dejun; Huo, Mingxin; Zhou, Dandan; Huo, Hongliang

    2017-02-06

     A novel micro-pressure swirl reactor (MPSR) was designed and applied to treat domestic wastewater at low temperature by acclimating microbial biomass with steadily decreasing temperature from 15 to 3 °C. Chemical oxygen demand (COD) was constantly removed by 85% and maintained below 50 mg L(-1) in the effluent during the process. When the air flow was controlled at 0.2 m(3) h(-1), a swirl circulation was formed in the reactor, which created a dissolved oxygen (DO) gradient with a low DO zone in the center and a high DO zone in the periphery for denitrification and nitrification. 81% of total nitrogen was removed by this reactor, in which ammonium was reduced by over 90%. However, denitrification was less effective because of the presence of low levels of oxygen. The progressively decreasing temperature favored acclimation of psychrophilic bacteria in the reactor, which replaced mesophilic bacteria in the process of treatment.

  18. Separation,screening and application of efficient degradation microorganisms for improving COD removing rates from organic chemical wastewater%有机化工废水COD高效降解菌的分离筛选及应用

    Institute of Scientific and Technical Information of China (English)

    张为艳; 刘鹏程; 郑凤娟; 吴敏; 张文武

    2016-01-01

    18 strains of COD degrading bacteria have been separated and screened from high altitude salt lake sam-ples in Xinjiang Province by using organic chemical wastewater medium for treating wastewater,after mixed with 8 strains of bacteria which have high COD degrading rates. Compared to other ordinary activated sludge,the mixed strains show higher COD removing rate (86.3%). Being identified preliminarily by 16S rDNA analysis,it shows that these 8 strains of bacteria belong to the varieties,including Bacteroidetes,Firmicutes and Proteobacteria. The mixed bacterial floras are used in bio-aeration pool tests. The COD removing rate could reach 82.5%,by adding 0.75 g/L of urea as nitrogen sources. The COD degrading rate could be improved to 92.2%,by adding 0.5 g/L of tuna peptone.%利用有机化工废水培养基从新疆高海拔盐湖样品中分离筛选到COD降解菌18株,对COD降解率高的8株菌株混合后处理废水,与其他普通活性污泥相比,COD去除率更高(86.3%)。经16S rDNA初步鉴定,该8株菌分别属于拟杆菌门Bacteroidetes、厚壁菌门Firmicutes和变形菌门Proteobacteria。将该混合菌群用于生物曝气池试验,添加尿素0.75 g/L作为氮源,其COD降解率可达82.5%;添加金枪鱼蛋白胨0.5 g/L可使COD降解率提高到92.2%。

  19. Performance of on-site pilot static granular bed reactor (SGBR) for treating dairy processing wastewater and chemical oxygen demand balance modeling under different operational conditions.

    Science.gov (United States)

    Oh, Jin Hwan; Park, Jaeyoung; Ellis, Timothy G

    2015-02-01

    The performance and operational stability of a pilot-scale static granular bed reactor (SGBR) for the treatment of dairy processing wastewater were investigated under a wide range of organic and hydraulic loading rates and temperature conditions. The SGBR achieved average chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS)-removal efficiencies higher than 90% even at high loading rates up to 7.3 kg COD/m(3)/day, with an hydraulic retention time (HRT) of 9 h, and at low temperatures of 11 °C. The average methane yield of 0.26 L CH4/g COD(removed) was possibly affected by a high fraction of particulate COD and operation at low temperatures. The COD mass balance indicated that soluble COD was responsible for most of the methane production. The reactor showed the capacity of the methanogens to maintain their activity and withstand organic and hydraulic shock loads.

  20. A modified method for COD determination of solid waste, using a commercial COD kit and an adapted disposable weighing support.

    Science.gov (United States)

    André, L; Pauss, A; Ribeiro, T

    2017-03-01

    The chemical oxygen demand (COD) is an essential parameter in waste management, particularly when monitoring wet anaerobic digestion processes. An adapted method to determine COD was developed for solid waste (total solids >15%). This method used commercial COD tubes and did not require sample dilution. A homemade plastic weighing support was used to transfer the solid sample into COD tubes. Potassium hydrogen phthalate and glucose used as standards showed an excellent repeatability. A small underestimation of the theoretical COD value (standard values around 5% lower than theoretical values) was also observed, mainly due to the intrinsic COD of the weighing support and to measurement uncertainties. The adapted COD method was tested using various solid wastes in the range of 1-8 mgCOD, determining the COD of dried and ground cellulose, cattle manure, straw and a mixed-substrate sample. This new adapted method could be used to monitor and design dry anaerobic digestion processes.

  1. COD removal and biogas production at the manipueira treatment in anaerobic one-stage reactor with different supporting media; Remocao de DQO e producao de biogas no tratamento de manipueira em reator anaerobico monofasico com diferentes meios de suporte

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Douglas Guedes Batista; Kunzler, Kathia Regina; Gomes, Simone Damasceno; Tavares, Maria Herminia Ferreira; Assis, Tatiane Martins de [Universidade Estadual do Oeste do Parana (UNIOESTE), PR (Brazil)], Emails: simoned@unioeste.br, mhstavar@certto.com.br

    2009-07-01

    This study aims at evaluating the efficiency for organic load removal and biogas production for the manipueira treatment in two anaerobic reactors using as supporting media bamboo rings and polyurethane. The manipueira loads added to the systems were 0.548, 1.156, 1.471 and 3.049 g COD/ L{sub reactorday}, gradually increased. With bamboo as supporting media, the load increasing carried the greatest biogas production, with 3.049 g COD/ L{sub reactorday}. Using polyurethane, the greatest production occurred with the 1.471 g CODL{sub reactorday} {sup -1}load. Therefore, it was shown that the supporting media use allowed greater loads and biogas productions, comparatively to the literature data. (author)

  2. Categorical analysis of factors affecting needs and demands for removable dentures among Alexandria Dental Research Center clientele.

    Science.gov (United States)

    Zeid, W M; Mohamed, M H; Mahdy, N H; El-Tabakh, S M

    1999-01-01

    An accurate assessment of dental needs is important to public health planners. With this information, it is possible to assess future treatment needs and demands for services including those for removable dentures. The present work aimed to estimate the magnitude and types of needs, and demands for partial or complete removable dentures, to study some factors that may affect the identified needs and demands for removable dentures, in addition to studying the factors that may affect satisfaction with the dentures. The present study was conducted in "Alexandria Dental Research Center". Data were collected by means of interview questionnaire, followed by dental examination of all patients attending the center for the sake of removable dental restorations for a period of 6 months. A further follow up over a period of three months was undertaken to the 330 cases recorded. About one third of the cases demanded partial and/or complete dentures and were above 60 years old. The first purpose for construction of new dentures was mastication, followed by cosmetics. Only one quarter of cases decided to have delayed immediate dentures. Diabetics and those having chronic diseases showed more demand for complete dentures. The most discriminating variable between the demand for different dentures was the missing in the lower anterior teeth followed by missing in the upper both anterior and posterior and then missing in the upper anterior teeth. Satisfaction score increased with advance of age, among males, among those for complete dentures, and those who had had previous dentures. Stepwise logistic regression revealed that the best predictor for overall satisfaction was the history of having previous dentures. Results of the present study, suggest that early screening and treatment of diabetic patients, gathering detailed information by means of a questionnaire before new dentures fabrication may be an important tool for the dentist in predicting and consequently enhancing patient

  3. The effect of microbubbles on gas-liquid mass transfer coefficient and degradation rate of COD in wastewater treatment.

    Science.gov (United States)

    Yao, Kangning; Chi, Yong; Wang, Fei; Yan, Jianhua; Ni, Mingjiang; Cen, Kefa

    2016-01-01

    A commonly used aeration device at present has the disadvantages of low mass transfer rate because the generated bubbles are several millimeters in diameter which are much bigger than microbubbles. Therefore, the effect of a microbubble on gas-liquid mass transfer and wastewater treatment process was investigated. To evaluate the effect of each bubble type, the volumetric mass transfer coefficients for microbubbles and conventional bubbles were determined. The volumetric mass transfer coefficient was 0.02905 s(-1) and 0.02191 s(-1) at a gas flow rate of 0.67 L min(-1) in tap water for microbubbles and conventional bubbles, respectively. The degradation rate of simulated municipal wastewater was also investigated, using aerobic activated sludge and ozone. Compared with the conventional bubble generator, the chemical oxygen demand (COD) removal rate was 2.04, 5.9, 3.26 times higher than those of the conventional bubble contactor at the same initial COD concentration of COD 200 mg L(-1), 400 mg L(-1), and 600 mg L(-1), while aerobic activated sludge was used. For the ozonation process, the rate of COD removal using microbubble generator was 2.38, 2.51, 2.89 times of those of the conventional bubble generator. Based on the results, the effect of initial COD concentration on the specific COD degradation rate were discussed in different systems. Thus, the results revealed that microbubbles could enhance mass transfer in wastewater treatment and be an effective method to improve the degradation of wastewater.

  4. Decolorization and COD reduction of dyeing wastewater from a cotton textile mill using thermolysis and coagulation.

    Science.gov (United States)

    Kumar, Pradeep; Prasad, B; Mishra, I M; Chand, Shri

    2008-05-01

    The decolorization and reduction of COD of dyeing wastewater from a cotton textile mill was conducted using catalytic thermal treatment (thermolysis) accompanied with/without coagulation. Thermolysis in presence of a homogeneous copper sulphate catalyst was found to be the most effective in comparison to other catalysts (FeCl(3), FeSO(4), CuO, ZnO and PAC) used. A maximum reduction of chemical oxygen demand (COD) and color of dyeing wastewater of 66.85% and 71.4%, respectively, was observed with a catalyst concentration of 5 kg/m(3) at pH 8. Commercial alum was found most effective coagulant among various coagulants (aluminum potassium sulphate, PAC, FeCl(3) and FeSO(4)) tested during coagulation operations, resulting in 58.57% COD and 74% color reduction at pH 4 and coagulant dose of 5 kg/m(3). Coagulation of the clear fluid (supernatant) obtained after treatment by thermolysis at the conditions previously used resulted in an overall reduction of 89.91% COD and 94.4% color at pH 4 and a coagulant dose of 2 kg/m(3). The application of thermolysis followed by coagulation, thus, is the most effective treatment method in removing nearly 90% COD and 95% color at a lower dose of coagulant (2 kg/m(3)). The sludge thus produced would contain lower inorganic mass coagulant and, therefore, less amount of inorganic sludge.

  5. Genome-Wide Transcriptional Profile Analysis of Prunus persica in Response to Low Sink Demand after Fruit Removal.

    Science.gov (United States)

    Duan, Wei; Xu, Hongguo; Liu, Guotian; Fan, Peige; Liang, Zhenchang; Li, Shaohua

    2016-01-01

    Prunus persica fruits were removed from 1-year-old shoots to analysis photosynthesis, chlorophyll fluorescence and genes changes in leaves to low sink demand caused by fruit removal (-fruit) during the final stage of rapid fruit growth. A decline in net photosynthesis rate was observed, accompanied with a decrease in stomatal conductance. The intercellular CO2 concentrations and leaf temperature increased as compared with a normal fruit load (+fruit). Moreover, low sink demand significantly inhibited the donor side and the reaction center of photosystem II. 382 genes in leaf with an absolute fold change ≥1 change in expression level, representing 116 up- and 266 down-regulated genes except for unknown transcripts. Among these, 25 genes for photosynthesis were down-regulated, 69 stress and 19 redox related genes up-regulated under the low sink demand. These studies revealed high leaf temperature may result in a decline of net photosynthesis rate through down-regulation in photosynthetic related genes and up-regulation in redox and stress related genes, especially heat shock proteins genes. The complex changes in genes at the transcriptional level under low sink demand provided useful starting points for in-depth analyses of source-sink relationship in P. persica.

  6. Removal of chemical oxygen demand and dissolved nutrients by a sunken lawn infiltration system during intermittent storm events.

    Science.gov (United States)

    Hou, Lizhu; Yang, Huan; Li, Ming

    2014-01-01

    Urban surface water runoff typically contains high but varying amounts of organic matter and nutrients that require removal before reuse. Infiltration systems such as sunken lawns can improve water quality. However, there is currently insufficient information describing the treatment efficiency of lawn-based infiltration systems. In this study, novel sunken lawn infiltration systems (SLISs) were designed and their pollutant removal effectiveness was assessed. The results revealed that SLISs with Poa pratensis and Lolium perenne effectively removed most chemical oxygen demand (CODCr) and dissolved nutrients. Average CODCr, total nitrogen (TN), ammonium-nitrogen (NH4(+)-N) and total phosphorus (TP) concentrations were reduced by 78.93, 66.64, 71.86 and 75.83%, respectively, and the corresponding effluent concentrations met the standard for urban miscellaneous water consumption in China. The NH4(+)-N in the synthetic runoff was shown to be removed by adsorption during the stormwater dosing and nitrification during subsequent dry days, as well as through uptake by plants. Phosphorus was mainly removed by adsorption and chemical precipitation. The NH4(+)-N and phosphorus Langmuir isotherm model fitted the clay loam soil adsorption process better than the Freundlich model. Overall, these results indicate that an SLIS provides an alternative means of removing runoff pollutants owing to its efficiency, easy operation and maintenance.

  7. Emerging micropollutants in water/wastewater: growing demand on removal technologies.

    Science.gov (United States)

    Trapido, M; Epold, I; Bolobajev, J; Dulova, N

    2014-11-01

    Developing advanced treatment technologies for improving the removal of micropollutants in water/wastewater is important. A suitable treatment is more likely to be used as the polishing step in the treatment scheme. Advanced oxidation technologies (AOTs) are relevant for removing micropollutants. The ability of direct UV photolysis and selected AOTs to degrade pharmaceuticals, endocrine-disrupting compound and herbicide has been studied and compared. The tested methods resulted in the degradation of the studied micropollutants; however, none of the methods was preferred for the removal of all tested compounds. The UV-active processes have strong potential for removal of the studied micropollutants. The utilisation of a moderate hydrogen peroxide admixture resulted in a more reliable treatment.

  8. Efficiency of some soil bacteria for chemical oxygen demand reduction of synthetic chlorsulfuron solutions under agiated culture conditions.

    Science.gov (United States)

    Erguven, G O; Yildirim, N

    2016-05-30

    This study searches the efficiency of certain soil bacteria on chemical oxygen demand (COD) reduction of synthetic chlorsulfuron solutions under agitated culture conditions. It also aims to determine the turbidity of liquid culture medium with chlorsulfuron during bacterial incubation for 120 hours. As a result the highest and lowest COD removal efficiency of bacteria was determined for Bacillus simplex as 94% and for Micrococcus luteus as 70%, respectively at the end of the 96th hour. It was found that COD removal efficiency showed certain differences depend on the bacterial species. It was also observed that B. simplex had the highest COD removal efficiency and it was a suitable bacterium species for bioremediation of a chlorsulfuron contaminated soils.

  9. On-Demand Removal of Bacterial Biofilms via Shape Memory Activation.

    Science.gov (United States)

    Gu, Huan; Lee, Sang Won; Buffington, Shelby Lois; Henderson, James H; Ren, Dacheng

    2016-08-24

    Bacterial biofilms are a major cause of chronic infections and biofouling; however, effective removal of established biofilms remains challenging. Here we report a new strategy for biofilm control using biocompatible shape memory polymers with defined surface topography. These surfaces can both prevent bacterial adhesion and remove established biofilms upon rapid shape change with moderate increase of temperature, thereby offering more prolonged antifouling properties. We demonstrate that this strategy can achieve a total reduction of Pseudomonas aeruginosa biofilms by 99.9% compared to the static flat control. It was also found effective against biofilms of Staphylococcus aureus and an uropathogenic strain of Escherichia coli.

  10. Particulate COD balance of particulate cod in eletrocuagulation/flotation reactor treating tannery effluent

    Directory of Open Access Journals (Sweden)

    Rodrigo Babora Borri

    2012-04-01

    Full Text Available Mass balance or particulate organic matter was studied in terms of COD, by means of electrocoagulation/flotation (ECF reactor treating tannery effluent. Reactor was operated in fill and draw (batch mode. Operating in hydraulic residence time of 65 minutes, ECF reactor reached 55 % COD removal. Although volatile solids were also removed from liquid phase (removal of 40%, fixed solids concentration, and hence total solids concentration, showed to be higher in withdrawn effluent than in ECF’s influent. This was assigned to NaCl added in order to enhance conductivity in wastewater.

  11. Photosynthetic response to low sink demand after fruit removal in relation to photoinhibition and photoprotection in peach trees.

    Science.gov (United States)

    Duan, Wei; Fan, Pei G; Wang, Li J; Li, Wei D; Yan, Shu T; Li, Shao H

    2008-01-01

    Diurnal variations in photosynthesis, chlorophyll fluorescence, xanthophyll cycle, antioxidant enzymes and antioxidant metabolism in leaves in response to low sink demand caused by fruit removal (-fruit) were studied in 'Zaojiubao' peach (Prunus persica (L.) Batch) trees during the final stage of rapid fruit growth. Compared with the retained fruit treatment (+fruit), the -fruit treatment resulted in a significantly lower photosynthetic rate, stomatal conductance and transpiration rate, but generally higher internal CO(2) concentration, leaf-to-air vapor pressure difference and leaf temperature. The low photosynthetic rate in the -fruit trees paralleled reductions in maximal efficiency of photosystem II (PSII) photochemistry and carboxylation efficiency. The midday depression in photosynthetic rate in response to low sink demand resulting from fruit removal was mainly caused by non-stomatal limitation. Fruit removal resulted in lower quantum efficiency of PSII as a result of both a decrease in the efficiency of excitation capture by open PSII reaction centers and an increase in closure of PSII reaction centers. Both xanthophyll-dependent thermal dissipation and the antioxidant system were up-regulated providing protection from photo-oxidative damage to leaves during low sink demand. Compared with the leaves of +fruit trees, leaves of -fruit trees had a larger xanthophyll cycle pool size and a higher de-epoxidation state, as well as significantly higher activities of antioxidant enzymes, including superoxide dismutase, ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, glutathione reductase and a higher reduction state of ascorbate and glutathione. However, the -fruit treatment resulted in higher hydrogen peroxide and malondialdehyde concentrations compared with the +fruit treatment, indicating photo-oxidative damage.

  12. Constructed Wetlands Systems Batch: removal of Biochemical Oxygen Demand and pH regulation for treatment dairy effluent

    Directory of Open Access Journals (Sweden)

    Henrique Vieira de Mendonça

    2015-04-01

    Full Text Available This work assessed the effectiveness of using constructed wetlands (CW's to treat dairy effluent. The purpose of the research was to evaluate the influence of substrates and cultivated plants on the efficiency of Biochemical Oxygen Demand (BOD removal and pH regulation in six experimental units operating at pilot scale. Six CW's for dairy sewage treatment were constructed in 100-liter High-Density Polyethylene Ethylene (HDPE tanks. Three constructed wetlands containing fine gravel (0 mm and another three with a mix of 20% sand and 80% fine gravel (0 mm were used in the filtering stage. Four experimental units were planted with the macrophytes Typha dominguensis (cattail and Hedychium coronarium (pond lily, the selected plants for this study, and two others were maintained as control units. A minimum average of 77.8% and a maximum of 95.2% BOD efficiency removal were achieved and a pH range of 5 to 9 was maintained as required by the Brazilian Resolution CONAMA N. 430 /2011 in order to release the effluent into a waterway. The six treatments showed similar removal of biodegradable carbonaceous compounds with no significant differences between the treatments at a 95% confidence level. This work showed that CW’s operating in batch can be used to treat dairy raw water for BOD removal and pH regulation.

  13. Phosphorus removal from secondary effluents through integrated constructed treatment system.

    Science.gov (United States)

    Xiong, Jibing; Qin, Yong; Mahmood, Qaisar; Liu, Hanhu; Yang, Dejun

    2011-01-01

    The treatment capacity of an integrated constructed treatment system (CTS) was explored which was designed to reduce phosphorus (P) from secondary effluents. The integrated CTS was combined with vertical-flow constructed wetland, floating bed and sand filter. The vertical wetland was filled from the bottom to the top with gravels, steel slag and peat. Vetiverzizanioides (L.) Nash was selected to grow in the vertical constructed wetland while Coixlacrymajobi L. was grown in floating bed. The results suggested that integrated CTS displayed excellent removal efficiency for chemical oxygen demand (COD), dissolved phosphorus (DP), and total phosphorus (TP). The average COD removal efficiency of the integrated CTS was 90.45% after 40 days of operation, the average DP and TP removal efficiencies of the integrated CTS were 97.43% and 96.40%, respectively. The integrated CTS has good potential in removing COD as well as P from secondary effluents. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Modeling BOD and COD removal from Palm Oil Mill Secondary Effluent in floating wetland by Chrysopogon zizanioides (L.) using response surface methodology.

    Science.gov (United States)

    Darajeh, Negisa; Idris, Azni; Fard Masoumi, Hamid Reza; Nourani, Abolfazl; Truong, Paul; Sairi, Nor Asrina

    2016-10-01

    While the oil palm industry has been recognized for its contribution towards economic growth and rapid development, it has also contributed to environmental pollution due to the production of huge quantities of by-products from the oil extraction process. A phytoremediation technique (floating Vetiver system) was used to treat Palm Oil Mill Secondary Effluent (POMSE). A batch study using 40 L treatment tanks was carried out under different conditions and Response Surface Methodology (RSM) was applied to optimize the treatment process. A three factor central composite design (CCD) was used to predict the experimental variables (POMSE concentration, Vetiver plant density and time). An extraordinary decrease in organic matter as measured by BOD and COD (96% and 94% respectively) was recorded during the experimental duration of 4 weeks using a density of 30 Vetiver plants. The best and lowest final BOD of 2 mg/L was obtained when using 15 Vetiver plants after 13 days for low concentration POMSE (initial BOD = 50 mg/L). The next best result of BOD at 32 mg/L was obtained when using 30 Vetiver plants after 24 days for medium concentration POMSE (initial BOD = 175 mg/L). These results confirmed the validity of the model, and the experimental value was determined to be quite close to the predicted value, implying that the empirical model derived from RSM experimental design can be used to adequately describe the relationship between the independent variables and response. The study showed that the Vetiver system is an effective method of treating POMSE.

  15. Adsorption of colour, TSS and COD from palm oil mill effluent (POME using acid-washed coconut shell activated carbon: Kinetic and mechanism studies

    Directory of Open Access Journals (Sweden)

    Sia Yong Yin

    2017-01-01

    Full Text Available The disposal of palm oil mill effluent (POME without proper treatment before being discharged into natural water sources has become undesirable because of high concentration of suspended solid (SS, oil and grease (O&G, chemical oxygen demand (COD and biological oxygen demand (BOD. This study investigated the feasibility of removing colour, total suspended solid (TSS and COD using acid-washed coconut shell based activated carbon (CSAC through the evaluation of the adsorption uptake as well as the adsorption kinetics and mechanism. The percentage removal of colour, TSS and COD from POME onto CSAC were 61%, 39%, 66%, respectively achieved within 48 hours of contact time. The kinetic models studied were pseudo-first-order (PFO, pseudo-second-order (PSO, and Elovich models. The intra-particle diffusion (IPD model was studied to interpret the adsorption diffusion mechanism. The adsorption of colour, TSS and COD onto CSAC were best interpreted by the PSO model, and well fitted by the Elovich model. The IPD and Boyd plots indicated that IPD and film diffusion controlled the adsorption of colour, TSS and COD onto the CSAC.

  16. Occurrence of anisakid nematodes in Atlantic cod (Gadus morhua) and Greenland cod (Gadus ogac), West Greenland

    DEFF Research Database (Denmark)

    Mouritsen, Kim N.; Hedeholm, Rasmus; Schack, Henriette B.;

    2010-01-01

    Anisakid nematodes commonly infect gadids, and are of economic and aesthetic importance to the commercial fishing industry in Greenland as some species are pathogenic to humans. However, very little is known about the occurrence of these parasites and their impact on the hosts in Greenland waters....... During a survey in 2005, stomach sample of 227 Atlantic cod (Gadus morhua) and 64 Greenland cod (Gadus ogac) was collected in Godthaab and Sisimiut fiord systems in West Greenland waters. All cod were dissected for stomach contents and anisakid nematodes were removed from the visceral cavity. Third stage...... nematode species regarding prevalence of infection and mean infection intensity was evident, and there was no relationship between fish condition and the intensity of nematode infections. Standardised for size, capelin-eating cod were in better condition and more heavily infected than fish subsisting...

  17. Simultaneous removal of carbon and nutrients from an industrial estate wastewater in a single up-flow aerobic/anoxic sludge bed (UAASB) bioreactor.

    Science.gov (United States)

    Asadi, A; Zinatizadeh, A A L; Sumathi, S

    2012-10-01

    Simultaneous removal of carbon and nutrients (CNP) in a single bioreactor is highly significant for energy consumption and control of reactor volume. Basically, nutrients removal is dependant to the ratio of biochemical oxygen demand to chemical oxygen demand (BOD₅/COD). Thus, in this study the treatment of an industrial estate wastewater with low BOD₅/COD ratio in an up-flow aerobic/anoxic sludge bed (UAASB) bioreactor, with an intermittent regime in aeration and discharge, was investigated. Hydraulic retention time (HRT) of 12-36 h and aeration time of 40-60 min/h were selected as the operating variables to analyze, optimize and model the process. In order to analyze the process, 13 dependent parameters as the process responses were studied. From the results, it was found, increasing HRT decreases the CNP removal efficiencies. However, by increasing the BOD₅ fraction of the feed, the total COD (TCOD), slowly biodegradable COD (sbCOD), readily biodegradable COD (rbCOD), total nitrogen (TN), and total phosphorus (TP) removal efficiencies were remarkably increased. Population of heterotrophic, nitrifying and denitrifying bacteria showed good agreement with the results obtained for TCOD and TN removal. The optimum conditions were determined as 12-15 h and 40-60 min/h for HRT and aeration time respectively.

  18. Isolation of microorganisms of cheese whey with lipolytic activity for removal of COD Isolamento de microrganismos do soro de queijo com atividade lipásica para remoção de DQO

    Directory of Open Access Journals (Sweden)

    Eliane Hermes

    2013-04-01

    Full Text Available The aim of this study was to isolate microorganisms that produce lipase and to assess the efficiency of COD removal intreatment of cheese whey under different operating conditions. The microorganisms were isolated from cheese whey and a commercial product; it was selectedthreemicroorganisms that obtained the best response to the lipolytic activity test through the enzyme index. Then, the microorganisms were inoculated in sterilized cheese whey samples, for two pH values (6.2 and 7.0, incubated at 35 °C and 150 rpm in shaker and the lipolityc activity and the efficiency of COD removal were measured in two time periods (24 and 48h. After incubation, it was observed that the treatments showed a good removal efficiency of COD for the pre-treatment and the isolated microorganism (S1 from the cheese whey showed the highest lipase production. Regarding the pH and time variables, there was not significant effect between the two evaluated factors. Among all treatments, T2 (S1, pH 7.0 and 24h obtained more enzyme production (4.87 U mL-1.O objetivo deste estudo foi isolar microrganismos produtores de lipase e avaliar a eficiência de remoção de DQO no tratamento de soro de leite sob diferentes condições operacionais. Os microrganismos foram isolados a partir do soro de queijo e de um produto comercial,e foram selecionados os três microrganismos que obtiveram a melhor resposta no teste da atividade lipolítica, através do índice enzimático. Em seguida, inocularam-se os micro-organismos em amostras de soro de queijo esterilizado, para dois valores de pH (6,2 e 7,0, incubaram-se a 35 ºC e 150 rpm em shaker e mensuram-se em dois períodos de tempo (24 e 48 h a atividade lipásica e a eficiência de remoção de DQO.Após a incubação, observou-se que os tratamentos apresentaram boa eficiência de remoção de DQO para o pré-tratamento,e o microrganismo (S1 isolado a partir do soro de queijo apresentou a maior produção de lipase. Com relação

  19. Effect of White Charcoal on COD Reduction in Wastewater Treatment

    Science.gov (United States)

    Pijarn, Nuchanaporn; Butsee, Manipa; Buakul, Kanokwan; Seng, Hasan; Sribuarai, Tinnphat; Phonprasert, Pongtep; Taneeto, Kla; Atthameth, Prasertsil

    2017-06-01

    The objective of this study is to compare the COD reduction in wastewater between using coconut shell and coconut spathe white charcoal from Khlong Wat NongPra-Ong, Krathumbaen, SamutSakhon province, Thailand. The waste water samples were collected using composite sampling method. The experimental section can be divided into 2 parts. The first part was study the optimum of COD adsorption time using both white charcoals. The second part was study the optimum amount of white charcoal for chemical oxygen demand (COD) reduction. The pre-treatment of wastewater was examined in parameters include temperature, alkalinity (pH), conductivity, turbidity, suspended solid (SS), total dissolved solid (TDS), and COD. The results show that both white charcoals can reduce COD of wastewater. The pH of pre-treatment wastewater had pH 9 but post-treatment wastewaters using both white charcoals have pH 8. The COD of pre-treatment wastewater had COD as 258 mg/L but post-treatment wastewater using coconut shell white charcoal had COD steady at 40 mg/L in 30 min and the amount of white charcoals 4 g. The COD of post-treatment wastewater using coconut spathe white charcoal had COD steady at 71 mg/L in 30 min and the amount of white charcoals 4 g. Therefore comparison of COD reduction between coconut shell white charcoal versus coconut spathe white charcoal found that the coconut shell white charcoal had efficiency for COD reduction better than coconut spathe white charcoal.

  20. COD biological removal and biogas production in anaerobic reactor treating cassava wastewater industry; Remocao biologica de DQO e producao de biogas em reator anaerobio tratando efluente de fecularia de madioca

    Energy Technology Data Exchange (ETDEWEB)

    Watthier, Elisangela [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil). Curso de Mestrado em Engenharia Agricola; Andreani, Cristiane Lurdes [Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Brasilia, DF (Brazil); Gomes, Simone Damasceno [Universidade Estadual do Oeste do Parana (PGEAGRI/UNIOESTE), Cascavel, PR (Brazil). Programa de Pos-Graduacao em Engenharia Agricola; Moreschi, Roberson; Rufino, Mauricio de Oliveira [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil). Curso de Engenharia Agricola

    2010-07-01

    The effluent from the cassava industry cause damage to the environment if released without treatment. One alternative is the implementation of anaerobic reactors, which also add value through the production of biogas. The support means increases the contact surface of micro-organisms and enhance their setting. The purpose of this study was to evaluate the reduction of organic matter (DQO) and biogas production in a reactor of PVC with 90 cm long and 15 cm in diameter, through support rings of bamboo, 10 cm in length and diameter ranged from 1.7 to 2.5 cm, with a volume of 6 L. The organic loading used were 4,357, 4,708, 5,601 and 6,126 g DQO.L-1.day-1, corresponding to hydraulic retention time (TRH) of 3,5, 2,8, 3,25 and 2,7 days, respectively. It was observed that with the increase of organic load was increased production of biogas, the largest observed for a load of 6.126 g DQO.L-1.day-1 with an average of 9.146 L.day-1. Regarding the removal of organic matter were achieved values of 98.35, 99.09, 99.33 and 98.55% respectively for each load applied, with the highest efficiency observed in charge of 5.601 g COD. L-1. day-1, but without significant differences. (author)

  1. Cod reproductive ecology

    DEFF Research Database (Denmark)

    Røjbek, Maria

    In recent decades, Baltic cod has experienced a period of low recruitment. In the same period the pelagic Baltic Sea ecosystem experienced a regime shift, due to hydrographic changes, affecting all trophic levels. The rationale for the thesis is built on the hypothesis that the regime shift has r...

  2. Start-up and characterization of nitrogen and COD removal from mature landfill leachatevia CANON process%CANON工艺处理实际晚期垃圾渗滤液的启动实验

    Institute of Scientific and Technical Information of China (English)

    张方斋; 王淑莹; 彭永臻; 苗蕾; 曹天昊; 王众

    2016-01-01

    针对晚期垃圾渗滤液4NH+-N浓度高、C/N低、深度脱氮困难的问题,采用 CANON 工艺在曝气/缺氧搅拌循环交替的运行方式下,处理晚期垃圾渗滤液实现了深度脱氮。系统经过130 d的驯化培养后成功启动,长期试验研究结果表明,在进水COD、4NH+-N、TN浓度(mg·L−1)分别为2050±250、1625±75和2005±352情况下,出水COD、4NH+-N、TN浓度(mg·L−1)能达到407±14、8±4和19±4,总氮去除率达到了98.76%。在未投加外碳源的情况下,CANON工艺在曝气/缺氧搅拌的运行方式下实现了对晚期垃圾渗滤液的深度脱氮。此外,经荧光原位杂交(FISH)检测表明,在该运行方式下能够成功富集氨氧化菌和厌氧氨氧化菌,各占总菌数的19.5%±1.3%和42.7%±5.02%,为CANON工艺用于处理晚期垃圾渗滤液的工程应用提供参考。%The mature landfill leachate from sanitary landfill is difficult to treat because of complicated composition, high concentration of ammonia and low C/N. During this study, a CANON (completely autotrophic nitrogen removal over nitrite) process with an intermittent aeration/anaerobic mixing operational mode was applied to remove nitrogen from mature landfill leachate. After domestication of 130 d, the system was stable with the effluent COD,4NH+-N and TN (mg·L−1) of 407±14, 8±4 and 19±4 when the influent COD,4NH+-N and TN (mg·L−1) were 2050±250, 1625±75 and 2005±352, respectively. Nitrogen removal from mature landfill leachate could be realizedvia intermittent aeration/anaerobic mixing CANON process with 98.76% of total nitrogen removal efficiency. Besides, the FISH (Fluorescencein situ hybridization) results showed that under this operational mode, both aerobic ammonium oxidation bacteria and anaerobic ammonium oxidizing bacteria accounted for 19.5%±1.3% and 42.7%±5.02%, respectively, which provided a reference for CANON treating mature landfill leachate in engineering

  3. Biological phosphorus removal inhibition by roxarsone in batch culture systems.

    Science.gov (United States)

    Guo, Qingfeng; Liu, Li; Hu, Zhenhu; Chen, Guowei

    2013-06-01

    Roxarsone has been extensively used in the feed of animals, which is usually excreted unchanged in the manure and eventually enter into animal wastewater, challenging the biological phosphorus removal processes. Knowledge of its inhibition effect is key for guiding treatment of roxarsone-contaminated wastewater, and is unfortunately keeping unclear. We study the inhibition of roxarsone on biological phosphorus removal processes for roxarsone-contaminated wastewater treatment, in terms of the removal and rates of chemical oxygen demand (COD), phosphate. Results showed that presence of roxarsone considerably limited the COD removals, especially at roxarsone concentration exceeding 40 mg L(-1). Additionally, roxarsone inhibited both phosphorus release and uptake processes, consistent with the phosphate profiles during the biological phosphorus removal processes; whereas, roxarsone is more toxic to phosphorus uptake process, than release function. The results indicated that it is roxarsone itself, rather than the inorganic arsenics, inhibit biological phosphorus removal processes within both aerobic and anaerobic roxarsone-contaminated wastewater treatment.

  4. The Denitrifying Biological Phosphorus Removal Performance in Anaerobic/Anoxic Sequencing Batch Reactor: The Effect of Carbon Source

    OpenAIRE

    Gürtekin, Engin; ŞEKERDAĞ, Nusret

    2015-01-01

    In this study, the effect of carbon source on denitrifying biological phosphorus removal performance in acetate and glucose fed two anaerobic/anoxic sequencinq batch reactor (SBR) was investigated. Glucose and acetate were used as the substrates. In acetate and glucose fed reactors, the COD (Chemical Oxygen Demand) removal efficiencies were 91,90% and PO4-P removal efficiencies were 87,51% respectively. These results shows that the phosphorus removal efficiency is lower in glucose fed reactor.

  5. The Denitrifying Biological Phosphorus Removal Performance in Anaerobic/Anoxic Sequencing Batch Reactor: The Effect of Carbon Source

    OpenAIRE

    Gürtekin, Engin; ŞEKERDAĞ, Nusret

    2015-01-01

    In this study, the effect of carbon source on denitrifying biological phosphorus removal performance in acetate and glucose fed two anaerobic/anoxic sequencinq batch reactor (SBR) was investigated. Glucose and acetate were used as the substrates. In acetate and glucose fed reactors, the COD (Chemical Oxygen Demand) removal efficiencies were 91,90% and PO4-P removal efficiencies were 87,51% respectively. These results shows that the phosphorus removal efficiency is lower in glucose fed reactor.

  6. Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes

    Institute of Scientific and Technical Information of China (English)

    ZAYAS Pérez Teresa; GEISSLER Gunther; HERNANDEZ Fernando

    2007-01-01

    The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculatio and advanced oxidation processes(AOP)had been studied.The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H202,UVO3 and UV/H-H202/O3 processes was determined under acidic conditions.For each of these processes,different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater.Coffee wastewater is characterized by a high chemical oxygen demand(COD)and low total suspended solids.The outcomes of coffee wastewater reeatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD,color,and turbidity.It was found that a reductiOn in COD of 67%could be realized when the coffee wastewater was treated by chemical coagulation-flocculatlon witll lime and coagulant T-1.When coffee wastewater was treated by coagulation-flocculation in combination with UV/H202,a COD reduction of 86%was achieved,although only after prolonged UV irradiation.Of the three advanced oxidation processes considered,UV/H202,uv/03 and UV/H202/03,we found that the treatment with UV/H2O2/O3 was the most effective,with an efficiency of color,turbidity and further COD removal of 87%,when applied to the flocculated coffee wastewater.

  7. Performance evaluation of low cost adsorbents in reduction of COD in sugar industrial effluent.

    Science.gov (United States)

    Parande, Anand K; Sivashanmugam, A; Beulah, H; Palaniswamy, N

    2009-09-15

    Studies on reduction of chemical oxygen demand (COD) in effluent from sugar industry have been carried out by employing different absorbents optimizing various parameters, such as initial concentration of adsorbate, pH, adsorbent dosage and contact time. Experimental studies were carried out in batches using metakaolin, tamarind nut carbon and dates nut carbon as adsorbents by keeping initial adsorbent dosage at 1 g l(-1), agitation time over a range of 30-240 min, adsorbent dosage at 100-800 mg l(-1) by varying the pH range from 4 to 10. Characterization of there adsorbents were done using techniques such as Fourier transforms infra red spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The experimental adsorption data fitted well to Langmuir and Freundlich adsorption isotherms. The isotherms of the adsorbents indicate appreciable adsorption capacity. Higher COD removal was observed at neutral pH conditions. Studies reveal that maximum reduction efficiency of COD takes place using metakaolin as an absorbent at a dosage of 500 mg l(-1) in a contact time of 180 min at pH 7 and it could be used as an efficient absorbent for treating sugar industrial effluent.

  8. Influence of Chemical Oxygen Demand Concentrations on Anaerobi Ammonium Oxidation by Granular Sludge From EGSB Reactor

    Institute of Scientific and Technical Information of China (English)

    JING KANG; JIAN-LONG WANG

    2006-01-01

    Objective To investigate the effect of chemical oxygen demand (COD) concentrations on the anaerobic ammonium oxidation (ANAMMOX). Methods An Expanded Granular Sludge Bed (EGSB) reactor was used to cultivate the granular sludge and to perform the ANAMMOX reaction in the bench scale experiment. NH4+-N and NO2--N were measured by usingcolorimetric method. NO3--N was analyzed by using the UV spectrophotometric method. COD measurement was based on digestion with potassium dichromate in concentrated sulphuric acid. Results When the COD concentrations in the reactors were 0 mg/L, 200 mg/L, 350 mg/L, and 550 mg/L, respectively, the NH4+-N removal efficiency was 12.5%, 14.2%, 14.3%, and 23.7%; the removal amount of NO2--N was almost the same; the nitrate removal efficiency was 16.8%, 94.5%, 86.6%, and 84.2% and TN removal efficiency was 16.3%, 50.7%, 46.9%, and 50.4%, moreover, the COD removal efficiency concentrations have a significant influence on anaerobic ammonium oxidation by granular sludge.

  9. Removal Factor Analysis of Chemical Oxygen Demand by Bipolar Pulsed Discharge in Dye Waste Water with Plasma Treatment%双极性脉冲放电等离子体处理染料废水时化学需氧量去除效果相关因素分析

    Institute of Scientific and Technical Information of China (English)

    张若兵; 马文长; 张弦

    2012-01-01

    在双极性脉冲放电等离子体用于染料废水的降解过程中,废水化学需氧量(chemicaloxygendemand,COD)的变化是在更深层次上反映该技术对有机污染物的降解能力的重要指标。为此,重点研究了在气液固三相混合体双极性脉冲放电条件下典型染料废水COD的去除规律,测试了不同电压、气体流量、初始浓度等条件下染料废水COD的变化。实验结果表明:当负载电压较高时,染料废水的COD值会先升高然后不断降低;而负载电压较低时,COD值会在一定程度内缓慢上升;气体流量越高,COD的去除效果越好;废水初始浓度增加,COD的去除率略有下降;初始电导率增加,COD的去除率降低;对具有不同官能团的染料废水进行放电处理发现,双极性脉冲放电对于各种结构的染料均有良好的处理效果。%The removal rule of chemical oxygen demand (COD) in the typical dye solution was investigated using a packed bed reactor by bipolar pulsed discharge in the air-water-solid mixture, and the value of COD in different conditions such as different voltages, air flow rates and initial concentrations was measured. Experimental results prove that the COD value of dye waste water will increase first and then decrease constantly at a high load voltage, while the COD value increase slowly to a certain extent at a low load voltage. The removal effect of COD is better when the air flow rate is higher and is worse when the initial concentration and conductivity of the dye waste water increase. It is found that the degradation effect on dyes with different functional groups is remarkable after the bipolar pulsed discharge treatment.

  10. 沸石负载接枝改性壳聚糖复合净水剂去除污水COD的研究%The Research for Graft Modification Chitosan Supported by Permutite and Its Removal of COD in Waste Water

    Institute of Scientific and Technical Information of China (English)

    王超莉; 刘坚; 胡炎发; 熊丽娟

    2014-01-01

    以生活污水为处理对象,通过对沸石、酸改性沸石、聚合氯化铝( PAC)改性后的沸石、沸石负载接枝改性壳聚糖复合净水剂进行COD去除对比试验.实验结果表明:沸石负载改性壳聚糖复合净水剂对COD有较高的去除率,对于COD浓度为400 mg·L-1的污水,在温度为25℃的条件下,经2 h搅拌接触, COD浓度可降至78 mg·L-1,去除率可达81%. SEM结果表明:壳聚糖部分包覆在沸石上,沸石负载接枝改性壳聚糖复合净水剂对COD的去除机理是复合净水剂表面(及内部孔隙)吸附作用和离子交换作用.对于普通自来水厂,只需将快滤池中常用的石英砂部分替换成沸石负载接枝改性壳聚糖复合净水剂即可有效去除水中的COD.%High concentration of COD in waste water is extremely harmful to human health. How to remove COD ef-ficiently and at low-cost in tap water has been a tough problem for numerous water plants. In this study,experiments were conducted using waste water to investigate the effect upon the COD removal test by Permutite modification with acid and PAC、graft modification Chitosan Supported by Permutite. The results show that graft modification Chitosan Supported by Permutite has better removal efficiency. Under the condition of temperature of 25 ℃,contact time for 2 h,the COD concentration in source water is decreased from 400 mg·L-1 to 78 mg·L-1 ,while the removal rate comes up to 81%. SEM indicated that CTS partially loaded on permutite. Loading number increased with m( CTS)/m( permut ite). The mechanism of removing COD by modified permutite is permutite surface( and internal pore)ad-sorption and ion exchange. Using modified permutite partially to replace the common quartz sand in fast filer is only needed for ordinary water plants to remove COD effectively in water.

  11. Removal of organic pollutants from oak leachate in pilot scale wetland systems: How efficient are aeration and vegetation treatments?

    Science.gov (United States)

    Svensson, Henric; Ekstam, Börje; Marques, Marcia; Hogland, William

    2015-11-01

    This study investigated the effects of aeration and/or vegetation in experimental constructed wetlands (CWs) as mesocosms on the removal of pollutants in oak wood leachate. Twelve outdoor wetland mesocosms, with randomized replicated treatment combinations of vegetation (Phragmites australis) and aeration was monitored during the second and third year after construction. The investigation included control tanks with no aeration and no vegetation. The parameters monitored were polyphenols (PPs), chemical oxygen demand (COD) and water colour. The reduction of COD after 28 days was approx. 50% and more than 50% of PPs, whereas only 40% of the water colour was removed. Aeration increased the effect of both COD and PP removal. The vegetation treatment had a small but significant effect on removal of COD. The vegetation + aeration treatment, as well as aeration alone, increased the removal efficiency of COD from 9.5 g m(-3) d(-1) in the control to 11 g m(-3) d(-1). The results suggest that CWs can be used to treat stormwater contaminated by oak wood leachate. Further, it is suggested that the main processes for removal of pollutants in the leachate occur in the open-water habitat and that the hydraulic retention time is more important for removal than aeration and vegetation related processes.

  12. 油田污水处理工艺中COD的去除研究进展%Research progress in COD removal in the process of oilfield wastewater treatment

    Institute of Scientific and Technical Information of China (English)

    刘涛; 包木太; 李希明; 郭省学; 汪卫东

    2009-01-01

    概述了油田污水的组成特点,并从近年来聚合物驱油和三元复合驱油产生污水带来的新问题出发,阐述了油田污水处理的难点所在.同时对当前油田污水处理工艺流程特点、实际工艺中存在的不足等作了比较,得出当前油田污水处理过程中工艺流程的选择标准和目标.重点对工艺处理中的絮凝沉降、生化处理以及膜法处理等不同的工艺流程中COD的去除进行了研究,通过比较各种方法得出在油田污水处理中利用生化法和膜处理方法的有机结合将是油田污水处理的主要发展方向.同时对当前油田污水处理中亟待需要解决的问题作了进一步表述.%The composition of oilfield wastewater is briefly introduced, and the difficulty in the wastewater treatment is dicussed, especialy that derived from the polymer flooding and alkali-surfactant-polymer flooding techniques widely used in recent years. The characteristics of the wastewater treatment technological processes are described) and their shortcomings in practical application are compared, through which the criterion and target for the process of oilfield wastewater treatment are obtained. Especially, the removal of COD in different treatment processes is discussed and compared, including flocculating setting, biological treatment and membrane treatment. It is suggested that the combination of biological method with membrane technique would be the major trend for oilfield wastewater treatment. Finally, the urgent issues that needed to be resolved in the disposal of oilfield wastewater are described.

  13. Biological phosphorus and nitrogen removal in a single sludge system

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, Hans

    1996-05-01

    The primary aim of this thesis was to investigate the process stability of a single sludge activated system designed for the combined operation of enhanced biological phosphorus removal (EBPR) and nitrogen removal. A pilot plant at the Sjoelunda wastewater treatment plant in Malmoe, Sweden, has formed the basis for the investigation. The pilot plant study showed that the concentration of total phosphorus on average was low in the effluent, below 0.5 mg P/l. Simultaneously with the highest concentrations of phosphorus in the effluent, the lowest COD/P ratios in the effluent were recorded. A recurrent pattern of high concentrations of phosphorus was observed every year in July, which is the industrial holiday month in Sweden. Other instances of increased phosphorus concentrations in the secondary effluent illustrate the effect of prolonged periods of rain. Increasing flow rates due to rain lead to a dilution and a change in the composition of the COD in the influent wastewater. The COD/P and VFA/P ratios decrease with decreasing concentrations of COD. It was also shown that high removal ratios of both nitrogen and phosphorus during long periods are possible. The nitrogen removal was stable during the whole investigated period, whereas the phosphorus removal was unstable during prolonged periods with low concentrations of COD in the influent water. The combined biological phosphorus and nitrogen removal process implies that during these periods the risk of recirculating nitrate to the anaerobic reactor increases. Such a recirculation both stabilizes the nitrogen removal and withdraws some of the readily degradable organic material from the bio-P bacteria. The main conclusion of this study is that a phosphorus limited EBPR process can cope with the day to day variations, but occasionally, measures have to be taken if the demands for phosphorus removal are stringent. 49 refs, 8 figs, 1 tab

  14. Peroxone mineralization of chemical oxygen demand for direct potable water reuse: Kinetics and process control.

    Science.gov (United States)

    Wu, Tingting; Englehardt, James D

    2015-04-15

    Mineralization of organics in secondary effluent by the peroxone process was studied at a direct potable water reuse research treatment system serving an occupied four-bedroom, four bath university residence hall apartment. Organic concentrations were measured as chemical oxygen demand (COD) and kinetic runs were monitored at varying O3/H2O2 dosages and ratios. COD degradation could be accurately described as the parallel pseudo-1st order decay of rapidly and slowly-oxidizable fractions, and effluent COD was reduced to below the detection limit (water, and a relationship is proposed and demonstrated to estimate the pseudo-first order rate constant for design purposes. At this O3/H2O2 mass ratio, ORP and dissolved ozone were found to be useful process control indicators for monitoring COD mineralization in secondary effluent. Moreover, an average second order rate constant for OH oxidation of secondary effluent organics (measured as MCOD) was found to be 1.24 × 10(7) ± 0.64 × 10(7) M(-1) S(-1). The electric energy demand of the peroxone process is estimated at 1.73-2.49 kW h electric energy for removal of one log COD in 1 m(3) secondary effluent, comparable to the energy required for desalination of medium strength seawater. Advantages/disadvantages of the two processes for municipal wastewater reuse are discussed.

  15. Contaminant removal performances on domestic sewage using modified anoxic/anaerobic/oxic process and micro-electrolysis.

    Science.gov (United States)

    Zhou, Jun; Gao, Jingqing; Liu, Yifan; Xiao, Shuai; Zhang, Ruiqin; Zhang, Zhenya

    2013-01-01

    The objective of this study was to enhance removal of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) from domestic sewage in a sequencing batch reactor with added new materials. A modified anoxic/anaerobic/oxic (MAAO) process, integrating a micro-electrolysis (ME) bed in an anoxic tank, and complex biological media (CBM) in anoxic, anaerobic and oxic tanks to treat domestic sewage, and their performances were investigated. The MAAO system was operated at controlled hydraulic retention time (HRT) of 8 h and mixed liquor recirculation (MLR) at 75%. The results showed that the MAAO system could effectively remove COD, TN and TP with average rates of 93%, 80% and 94%, respectively, in March, and 94%, 76% and 91%, respectively, in August. In this system, TP was primarily removed from the anoxic tank regardless of the operational conditions; removal contribution ratios to TP of the anoxic tank reached 56% both in March and August, indicating that the ME bed can effectively enhance phosphorus removal. TN was primarily removed from the anoxic and anaerobic tanks; removal contribution ratios to TN of anoxic and anaerobic tanks reached 36-38% and 37-38%, respectively. The oxic tank had the highest share of COD removal (56% both in March and August) in the removal of phosphorus. The outflow concentrations of COD, TN and TP were 3-46, 7-14 and 0.3-0.5 mg/L, respectively, in March, and 26-49, 9-15 and 0.04-0.1 mg/L, respectively, in August. COD and TN removal performances indicated that the innovative materials of the ME bed and CBM can effectively enhance COD and TN removal.

  16. Enhancing nitrogen removal from low carbon to nitrogen ratio wastewater by using a novel sequencing batch biofilm reactor.

    Science.gov (United States)

    Zou, Jinte; Li, Jun; Ni, Yongjiong; Wei, Su

    2016-12-01

    Removing nitrogen from wastewater with low chemical oxygen demand/total nitrogen (COD/TN) ratio is a difficult task due to the insufficient carbon source available for denitrification. Therefore, in the present work, a novel sequencing batch biofilm reactor (NSBBR) was developed to enhance the nitrogen removal from wastewater with low COD/TN ratio. The NSBBR was divided into two units separated by a vertical clapboard. Alternate feeding and aeration was performed in the two units, which created an anoxic unit with rich substrate content and an aeration unit deficient in substrate simultaneously. Therefore, the utilization of the influent carbon source for denitrification was increased, leading to higher TN removal compared to conventional SBBR (CSBBR) operation. The results show that the CSBBR removed up to 76.8%, 44.5% and 10.4% of TN, respectively, at three tested COD/TN ratios (9.0, 4.8 and 2.5). In contrast, the TN removal of the NSBBR could reach 81.9%, 60.5% and 26.6%, respectively, at the corresponding COD/TN ratios. Therefore, better TN removal performance could be achieved in the NSBBR, especially at low COD/TN ratios (4.8 and 2.5). Furthermore, it is easy to upgrade a CSBBR into an NSBBR in practice.

  17. Enhanced biological nutrient removal by the alliance of a heterotrophic nitrifying strain with a nitrogen removing ecosystem

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Nitrogen removal from synthetic wastewater was investigated in an airlift bioreactor (ALB), augmented with a novel heterotrophic nitrifier Pseudonocardia ammonioxydans H9T under organic carbon to nitrogen ratios (Corg/N) ranging from 0 to 12. Effect of the inoculated strain was also determined on the settling properties and the removal of chemical oxygen demand (COD). Two laboratory scale reactors were set up to achieve a stable nitrifying state under the same physicochemical conditions of hydraulic retention time (HRT), temperature, pH and dissolved oxygen (DO), and operated under the sequencing batch mode. The level of DO was kept at 0.5-1.5 mg/L by periodic stirring and aeration. Each specific Corg/N ratio was continued for duration of 3 weeks. One of the reactors (BR2) was inoculated with P. ammonioxydans H9T periodically at the start of each Corg/N ratio. Sludge volumetric index (SVI) improved with the increasing Corg/N ratio, but no significant difference was detected between the two reactors. BR2 showed higher levels of nitrogen removal with the increasing heterotrophic conditions, and the ammonia removal reached to the level of 82%-88%, up to10% higher than that in the control reactor (BR1) at Corg/N ratios higher than 6; however, the ammonia removal level in experimental reactor was up to 8% lower than that in control reactor at Corg/N ratios lower than 2. The COD removal efficiency progressively increased with the increasing Corg/N ratios in both of the reactors. The COD removal percentage up to peak values of 88%-94% in BR2, up to 11% higher than that in BR1 at Corg/N ratio higher than 4. The peak values of ammonia and COD removal almost coincided with the highest number (18%-27% to total bacterial number) of the exogenous bacterium in the BR2, detected as colony forming units (CFU). Furthermore, the removal of ammonia and COD in BR2 was closely related to the number of the inoculated strain with a coefficient index (R2) up to 0.82 and 0.85 for ammonia

  18. Organics removal of combined wastewater through shallow soil infiltration treatment: a field and laboratory study.

    Science.gov (United States)

    Zhang, Zhiyin; Lei, Zhongfang; Zhang, Zhenya; Sugiura, Norio; Xu, Xiaotian; Yin, Didi

    2007-11-19

    Soil infiltration treatment (SIT) was proved to be an effective and low-cost treatment technique for decentralized effluents in the areas without perfect sewage systems. Field-scale experiments were conducted under several conditions to assess organics removals through a shallow soil infiltration treatment (SSIT, with effective depth 0.3m) of combined wastewater (discharge from toilets, restaurants and a gas station), while bench-scale soil column experiments were performed in laboratory in parallel to investigate biological and abiological effects of this kind of system. From the start-up to the 10th month, the field SSIT trenches experienced the lowest and highest temperatures of the operation period in Shanghai and exhibited effective organics removals after maturation, with the highest removal rate 75.8% of chemical oxygen demand (COD), highest ultraviolet absorption at 254 nm (UV(254)) decrease by 67.2% and 35.2-100% removals of phenolic and phthalate pollutants. The laboratory results indicated that more organics could be removed in room-temperatured (25+/-2 degrees C) SSIT systems under different influent COD concentrations from 45 mg/l to 406 mg/l, and the highest total COD removal rate could reach 94.0%, in which biological effect accounted for 57.7-71.9%. The results showed that temperature and hydraulic loading rate were the most important factors influencing the removals of COD and organic pollutants in SSIT.

  19. Industry Based Survey (IBS) Cod

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The "Gulf of Maine Atlantic Cod Industry-Based Survey" was a collaboration of the Massachusetts Division of Marine Fisheries and the fishing industry, with support...

  20. Northeast Regional Cod Tagging Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientific justification: Canadian and US stock assessments for Atlantic cod indicate considerable fluctuation in stock abundance and recruitment over the last 20...

  1. Monitoring the desalting process of cod using dielectric spectroscopy.

    Science.gov (United States)

    De los Reyes, Ruth; Balbastre, Juan V; Andrés, Ana; Fito, Pedro; De los Reyes, Elias

    2009-01-01

    The desalted cod industry needs a suitable and reliable control system to check the desalting point of cod in order to provide a safe and high-quality product. The growth of the industries that are interested in a non-contacting, real-time control, encourages the development of new methods based on low-power radiation, such as dielectric spectroscopy. These techniques use the modification of wave parameters at some specific frequencies to provide information of the compositional characteristics of foods. In this work, cod parallelepipeds were desalted at 5 degrees C by immersing them in distilled water for different desalting times (15 and 30 minutes and 1, 2, 4, 6, 8, 12, 24 and 48 hours). Dielectric Spectroscopy studies have been performed on cod samples in the frequency range 200 MHz-20 GHz. The dielectric properties were measured using a coaxial probe (Agilent 85070E) connected to a Network Analyzer (Agilent E8362B) immediately after removing the cod samples from their desalting solutions. After desalting, the cod samples were separated from their desalting solutions and kept in repose for 24 h at 5 degrees C after which some of their physical properties were measured. This experimental procedure ensures that those properties have already reached their final values. Good correlations were found between the quality properties of the cod samples (a(w), Xw, Z(NaCl) and xNaCl) after 24 h and their loss factor (epsilon") measured at 10 GHz just before leaving them in repose, showing the feasibility of an in-line control system for cod desalting process at that frequency.

  2. Relationships between anaerobic consortia and removal efficiencies in an UASB reactor degrading 2,4 dichlorophenol (DCP).

    Science.gov (United States)

    Sponza, Delia Teresa; Cigal, Canan

    2008-04-01

    To gain more insight into the interactions between anaerobic bacteria and reactor performances (chemical oxygen demand-COD, 2,4 dichlorophenol-2,4 DCP removals, volatile fatty acid-VFA, and methane gas productions) and how they depended on operational conditions the microbial variations in the anaerobic granular sludge from an upflow anaerobic sludge blanket (UASB) reactor treating 2,4 DCP was studied. The study was composed of two parts. In the first part, the numbers of methanogens and acedogens in the anaerobic granular sludge were counted at different COD removal efficiencies. The relationships between the numbers of methanogens, the methane gas production and VFA production were investigated. The COD removal efficiencies increased to 74% from 30% while the number of total acedogens decreased to 10 from 30 cfu ml(-1). The number of total methanogens and acedogens varied between 11 x 10(3) and 10 x 10(9)MPN g(-1) and 10 and 30 cfu ml(-1) as the 2,4 DCP removal efficiencies were obtained between 60% and 99%, respectively. It was seen that, as the number of total acedogens decreased, the COD removal efficiencies increased. However, the number of total methanogens increased as the COD removal efficiencies increased. Correlations between the bacterial number and with the removal efficiencies obtained in different operational conditions were investigated. From the results presented in this paper a high correlation between the number of bacteria, COD removals, methane gas percentage, 2,4 DCP removals and VFA was observed. In the second part, methanogen bacteria in the anaerobic granular sludge were identified. Microbial observations and biochemical tests were applied to identify the anaerobic microorganisms from the anaerobic granular sludge. In the reactor treating 2,4 DCP, Methanobacterium bryantii, Methanobacterium formicicum, Methanobrevibacter smithii, Methanococcus voltae, Methanosarcina mazei, Methanosarcina acetivorans, Methanogenium bourgense and

  3. Kinetics of electro-oxidation of ammonia-N, nitrites and COD from a recirculating aquaculture saline water system using BDD anodes.

    Science.gov (United States)

    Díaz, V; Ibáñez, R; Gómez, P; Urtiaga, A M; Ortiz, I

    2011-01-01

    The viability of the electro-oxidation technology provided with boron doped diamond (BDD) electrodes for the treatment and reuse of the seawater used in a Recirculating Aquaculture System (RAS) was evaluated in this work. The influence of the applied current density (5-50 A m(-2)) in the removal of Total Ammonia Nitrogen (TAN), nitrite and chemical oxygen demand (COD) was analyzed observing that complete TAN removal together with important reductions of the other considered contaminants could be achieved, thus meeting the requirements for reuse of seawater in RAS systems. TAN removal, mainly due to an indirect oxidation mechanism was described by a second order kinetics while COD and nitrite removal followed zero-th order kinetics. The values of the kinetic constants for the anodic oxidation of each compound were obtained as a function of the applied current density (k(TAN) = 7.86 × 10(-5) · exp(6.30 × 10(-2) J); kNO2 = 3.43 × 10(-2) J; k(COD) = 1.35 × 10(-2) J). The formation of free chlorine and oxidation by-products, i.e., trihalomethanes (THMs) was followed along the electro-oxidation process. Although a maximum concentration of 1.7 mg l(-1) of total trihalomethanes was detected an integrated process combining electrochemical oxidation in order to eliminate TAN, nitrite and COD and adsorption onto activated carbon to remove the residual chlorine and THMs is proposed, as an efficient alternative to treat and reuse the seawater in fish culture systems. Finally, the energy consumption of the treatment has been evaluated.

  4. ACETONE REMOVAL AND BIOELECTRICITY GENERATION IN DUAL CHAMBER MICROBIAL FUEL CELL

    Directory of Open Access Journals (Sweden)

    Mostafa Rahimnejad

    2012-01-01

    Full Text Available Synthetic waste water contain organic compound can be oxidized in an anaerobic conditions in microbial fuel cell while biodegradation of Chemical Oxygen Demand (COD takes place under anaerobic condition in anode compartment. The microorganisms for biological treatment of the organic matter were obtained from a UASFB bioreactor. In the treatment of waste water, ones COD was removed the current and power was generated and record. Also polarization curve was obtained. In cathode compartment ferocynide and potassium permanganate with several concentration were add for enhancement of proton oxidation. The performance of MFC for maximum current and power generation were obtained with 300 µM L-1 potassium permanganate as oxidizers agent. Maximum generated power and current densities were 22 mW/m2 and 70 mA/m2, respectively. Active microorganisms used acetone as electron donors and COD removal was 69% at the end of process.

  5. External Carbon Source Addition as a Means to Control an Activated Sludge Nutrient Removal Process

    DEFF Research Database (Denmark)

    Isaacs, Steven Howard; Henze, Mogens; Søeberg, Henrik

    1994-01-01

    In alternating type activated sludge nutrient removal processes, the denitrification rate can be limited by the availability of readily-degradable carbon substrate. A control strategy is proposed by which an easily metabolizable COD source is added directly to that point in the process at which...... denitrification momentarily occurs. This approach serves to increase the denitrification rate on demand, thereby allowing the accumulation of nitrate and nitrite during periods of peak nitrogen loading to be reduced or avoided. A pilot plant demonstration of the control strategy using acetate as COD source...

  6. A New Spectrophotometric Method for Measuring COD of Seawater

    Institute of Scientific and Technical Information of China (English)

    LIU Ying; JI Hongwei; XIN Huizhen; LIU Li

    2006-01-01

    This research studied a new spectrophotometric method for measuring the chemical oxygen demand (COD) of seawater. In this method, the COD was measured using a spectrophotometer instead of titrating with sodium thiosulphate.The measuring wavelength was selected to be 470 nm, and the COD of three standard glucose solutions (COD = 0.5, 1.5 and2.5 mgL-1, respectively) and two seawater samples (from the South Yellow Sea and Jiaozhou Bay) were measured using the spectrophotometric method and titrimetric method respectively. The results showed that the spectrophotometric method was somewhat better than the titrimetric method. The relative standard deviation (RSD) of the spectrophotometric method was less than 2.7%, and the recovery of seawater samples ranged from 96.3% to 103.8%. In addition, the spectrophotometric method has other advantages such as expeditiousness, operation simplicity, analysis automatization, etc. Therefore the spectrophotometric method can be used to measure the COD of seawater with satisfactory results.

  7. Organic matter removal from saline agricultural drainage wastewater using a moving bed biofilm reactor.

    Science.gov (United States)

    Ateia, Mohamed; Nasr, Mahmoud; Yoshimura, Chihiro; Fujii, Manabu

    2015-01-01

    We investigated the effect of salinity on the removal of organics and ammonium from agricultural drainage wastewater (ADW) using moving bed biofilm reactors (MBBRs). Under the typical salinity level of ADW (total dissolved solids (TDS) concentration up to 2.5 g·L(-1)), microorganisms were acclimated for 40 days on plastic carriers and a stable slime layer of attached biofilm was formed. Next, six batch mode MBBRs were set up and run under different salinity conditions (0.2-20 g-TDS·L(-1)). The removal efficiency of chemical oxygen demand (COD) and ammonium-nitrogen (NH4-N) in 6 hours decreased from 98 and 68% to 64 and 21% with increasing salt concentrations from 2.5 to 20 g-TDS·L(-1), respectively. In addition, at decreasing salt levels of 0.2 g-TDS·L(-1), both COD removal and nitrification were slightly lowered. Kinetic analysis indicated that the first-order reaction rate constant (k1) and specific substrate utilization rate (U) with respect to the COD removal remained relatively constant (10.9-11.0 d(-1) and 13.1-16.1 g-COD-removed.g-biomass(-1)·d(-1), respectively) at the salinity range of 2.5-5.0 g-TDS·L(-1). In this study, the treated wastewater met the standard criteria of organic concentration for reuse in agricultural purposes, and the system performance remained relatively constant at the salinity range of typical ADW.

  8. Impacts of COD and DCP loading rates on biological treatment of 2,4-dichlorophenol (DCP) containing wastewater in a perforated tubes biofilm reactor.

    Science.gov (United States)

    Eker, Serkan; Kargi, Fikret

    2006-08-01

    Biofilm processes offer considerable advantages for biological treatment of chlorophenol containing wastewaters since such industrial effluents are difficult to treat by conventional activated sludge processes. A rotating perforated tubes biofilm reactor (RTBR) was developed and used for treatment of 2,4-dichlorophenol (DCP) containing synthetic wastewater. Effects of COD and DCP loading rates on COD, DCP and toxicity removals were investigated. Percent COD removal decreased and effluent COD increased with increasing COD and DCP loading rates due to toxic effects of high DCP content in the feed. DCP and toxicity removals showed similar trends. As the DCP loading rate increased the effluent DCP content increased yielding high toxicity levels in the effluent. COD and DCP loading rates should be below 90gCODm(-2)d(-1) and 2.8gDCPm(-2)d(-1) in order to obtain more than 90% DCP and toxicity removals. However, DCP loading rates lower than 1gDCPm(-2)d(-1) are required to obtain more than 90% COD removal. Empirical equations were developed to estimate percent COD, DCP and toxicity removals as functions of COD and DCP loading rates. The coefficients of the empirical equations were determined by using the experimental data. Empirical model predictions for percent COD, DCP and toxicity removals were in good agreement with the experimental data.

  9. 人工湿地对海水淡化厂污泥中重金属和COD去除效果的初步研究%Preliminary Study on the Removal Effect of Heavy Metal and COD in Sludge from Seawater Desalination with Constructed Wetland

    Institute of Scientific and Technical Information of China (English)

    石一民; 叶继红; 王波; 张海春

    2014-01-01

    选用芦苇作为人工湿地的植物,构建了4个规格为5 m×10 m×1.5 m的人工湿地,并进行了实验。结果表明:人工湿地对污泥中重金属Pb、Cd、Hg、As及渗滤液中COD均有一定的去除作用。系统经过6个月的试运行后,测得上述4种重金属的去除率在49%~65%之间;2013年8~11月期间测得的渗滤液中COD去除率不太稳定,最高为63.5%。本研究为合理利用人工湿地技术对海水淡化厂污泥进行稳定和无害化处理提供参考。%The reed was chosen to construct four wetlands with a size of 5 m×10 m×1.5 m and the exper-iments were conducted with these wetlands. The results indicated that the constructed wetlands had some effi-ciency for removal of heavy metal such as Pb, Cd, Hg, As in sludge and COD in percolate. After 6 months of the system running, the removal rate of the above heavy metals was between 49%-65%. But the removal rate of COD in percolate was not very stable and the highest value was 63.5% during the period of August to November 2013. The study provided some references for reasonable application of constructed wetland technol-ogy in stabilities and harmlessness of sludge from seawater desalination.

  10. Using a zeolite medium biofilter to remove organic pollutant and ammonia simultaneously

    Institute of Scientific and Technical Information of China (English)

    TIAN Wen-hua; WEN Xiang-hua; QIAN Yi

    2004-01-01

    A pilot scale zeolite medium biological aerated filter(ZBAF) was designed and used to treat municipal wastewater. It showed that ZBAF could simultaneously remove chemical oxygen demand(COD), ammonia-N and turbidity to satisfied degree at a hydraulic retention time(HRT) of 0.95 h. Their average removal efficiencies were 73.9%, 88.4% and 96.2% with the corresponding average effluent concentrations of 43.4 mg/L, 3.5 mg/L and 3.7 NTU, respectively. These effluent items met with the water quality standard of the treated water reused for cooling water. The COD removal volumetric loading rate increased proportionally with its applied volumetric loading rate removal efficiency in the future.

  11. Dynamics of microbial community structure and nutrient removal from an innovative side-stream enhanced biological phosphorus removal process.

    Science.gov (United States)

    Islam, Md Shahinoor; Zhang, Yanyan; Dong, Shimiao; McPhedran, Kerry N; Rashed, Ehab M; El-Shafei, Maha M; Noureldin, Ahmed M; Gamal El-Din, Mohamed

    2017-08-01

    Biological phosphorous (P) and nitrogen (N) removal from municipal wastewater was studied using an innovative anoxic-aerobic-anaerobic side-stream treatment system. The impact of influent water quality including chemical oxygen demand (COD), ammonium and orthophosphate concentrations on the reactor performance was evaluated. The results showed the system was very effective at removing both COD (>88%) and NH4(+)-N (>96%) despite varying influent concentrations of COD, NH4(+)-N, and total PO4(3-)-P. In contrast, it was found that the removal of P was sensitive to influent NH4(+)-N and PO4(3-)-P concentrations. The maximum PO4(3-)-P removal of 79% was achieved with the lowest influent NH4(+)-N and PO4(3-)-P concentration. Quantitative PCR (qPCR) assays showed a high abundance and diversity of phosphate accumulating organisms (PAO), nitrifiers and denitrifiers. The MiSeq microbial community structure analysis showed that the Proteobacteria (especially β-Proteobacteria, and γ-Proteobacteria) were the dominant in all reactors. Further analysis of the bacteria indicated the presence of diverse PAO genera including Candidatus Accumulibacter phosphatis, Tetrasphaera, and Rhodocyclus, and the denitrifying PAO (DPAO) genus Dechloromonas. Interestingly, no glycogen accumulating organisms (GAOs) were detected in any of the reactors, suggesting the advantage of proposed process in term of PAO selection for enhanced P removal compared with conventional main-stream processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Use of calcined layered double hydroxides for the removal of color and organic matter from textile effluents: kinetic, equilibrium and recycling studies

    Directory of Open Access Journals (Sweden)

    T. P. F. Teixeira

    2014-03-01

    Full Text Available This paper presents data for the synthesis and characterization of layer double hydroxides (LDH and their use for color and chemical oxygen demand (COD removal from effluents generated by a textile industry. Adsorption studies with raw and biologically treated (activated sludge textile effluent showed that the pseudo-second order model best fitted the experimental data, leading to adsorption coefficients of 39.1 and 102.9 mgCOD/gLDH for raw and treated effluents, respectively. The best conditions for color and COD removal were obtained at lower values of temperature and pH (25 °C and pH 7 and, in these conditions, an LDH dose of 10 g/L resulted in color removal efficiencies of 56% for samples of raw and 66% for samples of treated effluent. Recycling studies indicated that the reuse of thermally treated LDH led to a progressive loss in the removal efficiencies of COD and color. The reduction was more pronounced with samples of the raw textile effluent. LDH characterization performed before and after each adsorption and regeneration experiment showed that there was no intercalation of dye molecules in the interlayer region of the LDH, indicating that COD and color removal might be due to the adsorption of organic molecules onto the LDH surface.

  13. Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal

    Institute of Scientific and Technical Information of China (English)

    A.R. Majdi Nasab; S.M. Soleymani; M. Nosrati; S.M. Mousavi

    2016-01-01

    A pilot scale modified step-feed process was improved to increase nutrient (N and P) and organic removal operations from municipal wastewater. It combined the step-feed process and a method named“University of Cape Town (UCT)”. The effect of nutrient ratios and inflow distribution ratios were studied. The highest uptake efficiency of 95%for chemical oxygen demand (COD) has been achieved at the inflow distribution ratio of 40/35/25. However, maximum removal efficiency obtained for total nitrogen (TN) and phosphorus at 93%and 78%, respectively. The average mixed liquor suspended solids (MLSS) was 5500 mg·L−1. In addition, convenient values for dissolved oxygen (DO) concentration, and pH were obtained throughout different stages. The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal, sturdy sludge settle ability and COD removal.

  14. Long-term effects of the transient COD concentration on the performance of microbial fuel cells.

    Science.gov (United States)

    Mateo, S; Gonzalez Del Campo, A; Lobato, J; Rodrigo, M; Cañizares, P; Fernandez-Morales, F J

    2016-07-08

    In this work, the long-term effects of transient chemical oxygen demands (COD) concentrations over the performance of a microbial fuel cell were studied. From the obtained results, it was observed that the repetitive change in the COD loading rate during 12 h conditioned the behavior of the system during periods of up to 7 days. The main modifications were the enhancement of the COD consumption rate and the exerted current. These enhancements yielded increasing Coulombic efficiencies (CEs) when working with COD concentrations of 300 mg/L, but constant CEs when working with COD concentrations from 900 to 1800 mg/L. This effect could be explained by the higher affinity for the substrate of Geobacter than that of the nonelectrogenic organisms such as Clostridia. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:883-890, 2016.

  15. Hydrophobic organic chemicals (HOCs) removal from biologically treated landfill leachate by powder-activated carbon (PAC), granular-activated carbon (GAC) and biomimetic fat cell (BFC).

    Science.gov (United States)

    Liyan, Song; Youcai, Zhao; Weimin, Sun; Ziyang, Lou

    2009-04-30

    Biological pretreatment efficiently remove organic matter from landfill leachate, but further removal of refractory hydrophobic organic chemicals (HOCs) is hard even with advanced treatment. In this work, three-stage-aged refuse bioreactor (ARB) efficiently removed chemical oxygen demand (COD) and biochemical oxygen demand (BOD) of fresh leachate produced in Shanghai laogang landfill, from 8603 to 451 mg L(-1) and 1368 to 30 mg L(-1), respectively. In downstream treatment, 3 g L(-1) powder-activated carbon (PAC), granular-activated carbon (GAC) and biomimetic fat cell (BFC) removed 89.2, 73.4 and 81.1% HOCs, but only 24.6, 19.1 and 8.9% COD, respectively. Through the specific HOCs accumulation characteristics of BFC, about 11.2% HOCs with low molecular weight (effluent exhibited a wide molecular weight distribution (34-514,646 Da). These constitutes are derived from both autochthonous and allochthonous matters as well as biological activities.

  16. Occurrence and removal of organic micropollutants in the treatment of landfill leachate by combined anaerobic-membrane bioreactor technology

    Institute of Scientific and Technical Information of China (English)

    XU Yiping; ZHOU Yiqi; WANG Donghong; CHEN Shaohua; LIU Junxin; WANG Zijian

    2008-01-01

    Organic micropollutants, with high toxicity and environmental concern, are present in the landfill leachate at much lower levels than total organic constituents (chemical oxygen demand (COD), biochemical oxygen demand (BOD), or total organic carbon (TOC)), and few has been known for their behaviors in different treatment processes. In this study, occurrence and removal of 17 organochlorine pesticides (OCPs), 16 polycyelic aromatic hydrocarbons (PAHs), and technical 4-nonylphenol (4-NP) in landfill leachate in a combined anaerobic-membrane bioreactor (MBR) were investigated. Chemical analyses were performed in leachates sampled from different treatment processes, using solid-phase extraction and gas chromatography with electron capture detector and mass spectrometry.Concentrations of OCPs, PAHs, and 4-NP in the raw leachate were detected within the range from ND (not detected) to 595.2 ng/L,which were as low as only 10-7-10-5 percentage of TOC (at the concentration of 2,962 mg/L). The removal of 4-NP was mainly established in the MBR process, in agreement with removals of COD, BOD, and TOC. However, the removals of OCPs and PAHs were different, mainly achieved in the anaerobic process. High removal efliciencies of both total organic constituents and organic micropollutants could be achieved by the combined anaerobic-MBR technology. The removal efficiencies of total organic constituents were in the order of BOD (99%) > COD (89%) > TOC (87%), whereas the removal efficiencies of investigated organic micropollutants were as follows: OCPs (94%) > 4-NP (77%) > PAHs (59%).

  17. Intensified nitrogen removal in immobilized nitrifier enhanced constructed wetlands with external carbon addition.

    Science.gov (United States)

    Wang, Wei; Ding, Yi; Wang, Yuhui; Song, Xinshan; Ambrose, Richard F; Ullman, Jeffrey L

    2016-10-01

    Nitrogen removal performance response of twelve constructed wetlands (CWs) to immobilized nitrifier pellets and different influent COD/N ratios (chemical oxygen demand: total nitrogen in influent) were investigated via 7-month experiments. Nitrifier was immobilized on a carrier pellet containing 10% polyvinyl alcohol (PVA), 2.0% sodium alginate (SA) and 2.0% calcium chloride (CaCl2). A batch experiment demonstrated that 73% COD and 85% ammonia nitrogen (NH4-N) were degraded using the pellets with immobilized nitrifier cells. In addition, different carbon source supplement strategies were applied to remove the nitrate (NO3-N) transformed from NH4-N. An increase in COD/N ratio led to increasing reduction in NO3-N. Efficient nitrification and denitrification promoted total nitrogen (TN) removal in immobilized nitrifier biofortified constructed wetlands (INB-CWs). The results suggested that immobilized nitrifier pellets combined with high influent COD/N ratios could effectively improve the nitrogen removal performance in CWs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Monitoring sodium chloride during cod fish desalting process by flow injection spectrometry and infrared spectroscopy

    OpenAIRE

    Galvis-Sánchez, Andrea C.; Ildikó V. Tóth; Portela, Ana; Delgadillo, Ivonne; Rangel,António O. S. S.

    2011-01-01

    In order to adapt to the market trends that are moving towards ready-to-use products cod !sh industry is including into their industrial operations as the desalting step. The desalting process is a high cost and time demanding operation. The optimization of the desalting process is of vital importance for the !sh industry in order to assure the homogeneity and predictable concentration of sodium chloride in the !nal hydrated cod !sh product. On the other hand, consumers are more a...

  19. A Combined System for Biological Removal of Nitrogen and Carbon from Nylon-6 Production Wastewater

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; LIU Guo-hua; TIAN Qing; ZHANG Man; CHEN Ji-hua

    2007-01-01

    A combined system consisting of hydrolysisacidification, denitrification and nitrification reactors wasused to remove carbon and nitrogen from the nylon - 6production wastewater, which was characterized by goodbiodegradability and high nitrogen concentration. Theinfluences of Chemical Oxygen Demand(COD) in theinfluent, recirculation ratio, Hydraulic Residence Time(HRT) and Dissolved Oxygen(DO) concentration on thesystem performances were investigated. From results itcould be seen that good performances have been achievedduring the overall experiments periods, and COD, TotalNitrogen(TN), NH+-N and Suspended Solids(SS) in theeffluent were 53, 16, 2 and 24 mg·L-1, respectively,which has satisfied the first standard of wastewaterdischarge established by Environmental Protection Agency(EPA) of China. Furthermore, results showed thatoperation factors, viz. COD in the influent, recirculationratio, HRT and DO concentration, all had importantinfluences on the system performances.

  20. Effect of COD:SO4 2− Ratio, HRT and Linoleic Acid Concentration on Mesophilic Sulfate Reduction: Reactor Performance and Microbial Population Dynamics

    Directory of Open Access Journals (Sweden)

    Chungman Moon

    2015-05-01

    Full Text Available Biological sulfate (SO42− reduction was examined in anaerobic sequential batch reactors (ASBRs operated under different hydraulic retention times (HRTs ranging from 12 to 36 h and COD (Chemical Oxygen Demand/SO42− ratios of 2.4, 1.6 and 0.8. Competition between SO42− reducing bacteria (SRBs, methane producing archaea (MPAs and homoacetogens (HACs was examined in controls and cultures treated with linoleic acid (LA. The ASBR performance was influenced by the COD/SO42− ratio in control cultures with a SO42− reduction of 87% at a COD/SO42− ratio of 0.8. At a 12 h HRT, in both control and LA treated cultures, greater than 75% SO42− removal was observed under all the conditions examined. In control reactors operating at a 36 h HRT, high levels of MPAs belonging to Methanobacteriales and Methanosarcinales were detected; however, in comparison, under low COD/SO42− ratio and with decreasing HRT conditions, a relative increase in SRBs belonging to Desulfovibrio and Desulfatibacillum was observed. Adding 0.5 g·L−1 LA suppressed Methanobacteriales, while increasing the LA concentration to 1 g·L−1 completely suppressed MPAs with a relative increase in SRBs. HACs belonging to Bacteroidetes were observed in the control and in cultures operated at 12 h HRT with a COD/SO42− ratio of 1.6 and fed 0.5 g·L−1 LA; however, with all other LA levels (0.5 and 1.0 g·L−1 and HRTs (12, 24 and 36 h, HACs were not detected.

  1. Removing nitrogen and phosphorus from simulated wastewater using algal biofilm technique

    Institute of Scientific and Technical Information of China (English)

    Qun WEI; Zhiquan HU; Genbao LI; Bo XIAO; Hao SUN; Meiping TAO

    2008-01-01

    Algal biofilm technology is a new and advanced wastewater treatment method. Experimental study on removing nitrogen and phosphorus from simulated waste-water using algal biofilm under the continuous light of 3500 Lux in the batch and continuous systems was carried out in this paper to assess the performance of algal biofilm in removing nutrients. The results showed that the effect of removing nitrogen and phosphorus by algal biofilm was remarkable in the batch system. The removal efficiencies of total phosphorus (TP), total nitrogen (TN), ammonia-nitrogen (NH3-N), and chemical oxygen demand (COD) reached 98.17%, 86.58%, 91.88%, and 97.11%, respect-ively. In the continuous system, hydraulic retention time (HRT) of 4 days was adopted; the effects of removing TP, TN, NH3-N, and COD by algal biofilm were very stable. During a run of 24 days, the removal efficiencies of TP, TN, NH3-N, and COD reached 95.38%, 83.93%, 82.38%, and 92.31%, respectively. This study demonstrates the feasibility of removing nitrogen and phosphorus from simulated wastewater using algal biofilm.

  2. Decolorization and COD reduction of UASB pretreated poultry manure wastewater by electrocoagulation process: A post-treatment study

    Energy Technology Data Exchange (ETDEWEB)

    Yetilmezsoy, Kaan [Department of Environmental Engineering, Yildiz Technical University, 34349 Yildiz, Besiktas, Istanbul (Turkey)], E-mail: yetilmez@yildiz.edu.tr; Ilhan, Fatih; Sapci-Zengin, Zehra; Sakar, Suleyman; Gonullu, M. Talha [Department of Environmental Engineering, Yildiz Technical University, 34349 Yildiz, Besiktas, Istanbul (Turkey)

    2009-02-15

    The performance of electrocoagulation (EC) technique for decolorization and chemical oxygen demand (COD) reduction of anaerobically pretreated poultry manure wastewater was investigated in a laboratory batch study. Two identical 15.7-L up-flow anaerobic sludge blanket (UASB) reactors were first run under various organic and hydraulic loading conditions for 216 days. Effects of operating parameters such as type of sacrificial electrode material, time of electrolysis, current density, initial pH, and electrolyte concentration were further studied to optimize conditions for the post-treatment of UASB pretreated poultry manure wastewater. Preliminary tests conducted with two types of sacrificial electrodes (Al and Fe) resulted that Al electrodes were found to be more effective for both COD and color removals than Fe electrodes. The subsequent EC tests performed with Al electrodes showed that optimal operating conditions were determined to be an initial pH of 5.0, a current density of 15 mA/cm{sup 2}, and an electrolysis time of 20 min. The results indicated that under the optimal conditions, about 90% of COD and 92% of residual color could be effectively removed from the UASB effluent with the further contribution of the EC technology used as a post-treatment unit. In this study, the possible acute toxicity of the EC effluent was also evaluated by a static bioassay test procedure using guppy fish (Lebistes reticulatus). Findings of this study clearly indicated that incorporation of a toxicological test into conventional physicochemical analyses provided a better evaluation of final discharge characteristics.

  3. Upgrading of an activated sludge wastewater treatment plant by adding a moving bed biofilm reactor as pre-treatment and ozonation followed by biofiltration for enhanced COD reduction: design and operation experience.

    Science.gov (United States)

    Kaindl, Nikolaus

    2010-01-01

    A paper mill producing 500,000 ton of graphic paper annually has an on-site wastewater treatment plant that treats 7,240,000 m³ of wastewater per year, mechanically first, then biologically and at last by ozonation. Increased paper production capacity led to higher COD load in the mill effluent while production of higher proportions of brighter products gave worse biodegradability. Therefore the biological capacity of the WWTP needed to be increased and extra measures were necessary to enhance the efficiency of COD reduction. The full scale implementation of one MBBR with a volume of 1,230 m³ was accomplished in 2000 followed by another MBBR of 2,475 m³ in 2002. An ozonation step with a capacity of 75 kg O₃/h was added in 2004 to meet higher COD reduction demands during the production of brighter products and thus keeping the given outflow limits. Adding a moving bed biofilm reactor prior to the existing activated sludge step gives: (i) cost advantages when increasing biological capacity as higher COD volume loads of MBBRs allow smaller reactors than usual for activated sludge plants; (ii) a relief of strain from the activated sludge step by biological degradation in the MBBR; (iii) equalizing of peaks in the COD load and toxic effects before affecting the activated sludge step; (iv) a stable volume sludge index below 100 ml/g in combination with an optimization of the activated sludge step allows good sludge separation--an important condition for further treatment with ozone. Ozonation and subsequent bio-filtration pre-treated waste water provide: (i) reduction of hard COD unobtainable by conventional treatment; (ii) controllable COD reduction in a very wide range and therefore elimination of COD-peaks; (iii) reduction of treatment costs by combination of ozonation and subsequent bio-filtration; (iv) decrease of the color in the ozonated wastewater. The MBBR step proved very simple to operate as part of the biological treatment. Excellent control of the COD-removal

  4. [Stability of Short-cut Nitrification Nitrogen Removal in Digested Piggery Wastewater with an Intermittently Aerated Sequencing Batch Reactor].

    Science.gov (United States)

    Song, Xiao-yan; Liu, Rui; Shui, Yong; Kawagishi, Tomoki; Zhan, Xin-min; Chen, Lu-jun

    2016-05-15

    Stability of short-cut nitrification nitrogen removal performance was studied in a step-feeding, intermittently aerated sequencing batch reactor (IASBR) at 30°C to treat digested piggery wastewater. Results showed that the nitrogen removal was greatly influenced by the ratio of chemical oxygen demand (COD) to total nitrogen (TN) in the influent. Nitrite nitrogen kept accumulating up to 800 mg · L⁻1 when the influent COD/TN ratio was 0.8 ± 0.2, and the removal rates of TN, ammonium nitrogen and total organic carbon (TOC) were only 18.3% ± 12.2%, 84.2% ± 10.3% and 60.7% ± 10.7%, respectively. By contrast, as the influent COD/ TN ratio was increased to 2.4 ± 0.5, the accumulated concentration of nitrite nitrogen sharply decreased from 800 mg · L⁻¹ to below 10 mg-L⁻¹, and the removal rates of TN, ammonium nitrogen and TOC were increased to over 90%, 95% and 85%, respectively. Gradually shortened hydraulic retention time ( HRT) reveales that the ammonia load is a restricting factor for nitrogen removal. The ammonia load should be controlled at no more than 0.30 kg · (m³ · d) ⁻¹, or else, the removal rates of TN, ammonium and TOC would be greatly decreased. The nitrite accumulation rate over the whole run was 74.6%-97.8% and the TN removal rate in the stable phase was over 90%. With efficient and stable short-cut nitrification-denitrification in a low COD/TN, moreover, and unnecessary for addition of alkaline, IASBR shows great advantage for treating wastewater with high concentration of ammonia while low COD/TN ratio.

  5. Pemodelan matematis pengurangan COD dalam air limbah industri penyamakan kulit secara adsorpsi kontinyu menggunakan abu terbang bagas

    Directory of Open Access Journals (Sweden)

    Agus Prasetya

    2013-06-01

    Full Text Available The objective of this research was to obtain suitable mathematical model for Chemical Oxygen Demand (COD removal originated from tannery wastewater using bagasse fly ash in continuous system. In the column experiment, effect of flowrate, concentration of wastewater, and bulk density were studied. Three models: Adams-Bohart, Thomas, and Yan were applied to experimental data to predict the breakthrough curve. The best model was evaluated using correlation coefficients. Yan model was found to give the most accurate to describe dynamic behavior of the column experiment. The best result was obtained at flowrate of 100 mL/min, concentration of 400 mg/L, and bulk density of 61 g/L. The Yan kinetic constant (k and the Y adsorption capacity (q were 0.3210 mL/mg/min and 17.0947 mg/g respectively and the Y correlation coefficient obtained was 0.9379.

  6. Removal of nitrogen and organic matter in a submerged-membrane bioreactor operating in a condition of simultaneous nitrification and denitrification

    Directory of Open Access Journals (Sweden)

    Izabela Major Barbosa

    2016-04-01

    Full Text Available This study evaluated the removal of nitrogen and organic matter in a membrane bioreactor system operating in a condition of simultaneous nitrification and denitrification controlled by intermittent aeration. A submerged-membrane system in a bioreactor was used in a pilot scale to treat domestic wastewater. The dissolved oxygen concentration was maintained between 0.5 and 0.8 mg L-1. The concentration of the mixed liquor suspended solids (MLSS in the system ranged from 1 to 6 g L-1. The system efficiency was evaluated by the removal efficiency of organic matter, quantified by Chemical Oxygen Demand (COD, Biochemical Oxygen Demand (BOD5 and Total Organic Carbon (TOC. Nitrogen removal was assessed by quantifying Total Kjeldahl Nitrogen (TKN and ammonia nitrogen. During the system start-up, the removal efficiencies of COD and NTK were around 90% and 80%, respectively. After the simultaneous nitrification and denitrification (SND conditions were established, the removal efficiencies of COD and NTK were 70% and 99%, respectively. These results showed that sewage treatment with the membrane bioreactor (MBR system, operating with simultaneous nitrification and denitrification conditions, was able to remove organic matter and promote nitrification and denitrification in a single reactor, producing a high-quality permeate.

  7. Removal of anaerobic soluble microbial products in a biological activated carbon reactor.

    Science.gov (United States)

    Dong, Xiaojing; Zhou, Weili; He, Shengbing

    2013-09-01

    The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable. Focusing on the biodegradation of anaerobic SMP, the biological activated carbon (BAC) was introduced into the anaerobic system. The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors. The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2, i.e., BAC) functioned as a polishing step to remove SMP produced in UASB1. The results showed that 90% of the SMP could be removed before granular activated carbon was saturated. After the saturation, the SMP removal decreased to 60% on the average. Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation. A strain of SMP-degrading bacteria, which was found highly similar to Klebsiella sp., was isolated, enriched and inoculated back to the BAC reactor. When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m3 x day), the effluent from the BAC reactor could meet the discharge standard without further treatment. Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective, cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L.

  8. Integrated physicochemical and biological treatment process for fluoride and phosphorus removal from fertilizer plant wastewater.

    Science.gov (United States)

    Gouider, Mbarka; Mlaik, Najwa; Feki, Mongi; Sayadi, Sami

    2011-08-01

    The phosphate fertilizer industry produces highly hazardous and acidic wastewaters. This study was undertaken to develop an integrated approach for the treatment of wastewaters from the phosphate industry. Effluent samples were collected from a local phosphate fertilizer producer and were characterized by their high fluoride and phosphate content. First, the samples were pretreated by precipitation of phosphate and fluoride ions using hydrated lime. The resulting low- fluoride and phosphorus effluent was then treated with the enhanced biological phosphorus removal (EBPR) process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two-stage anaerobic/aerobic system operating under continuous flow. Pretreated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate (OLR) from 0.3 to 1.2 g chemical oxygen demand (COD)/L.d. The stable and high removal rates of COD, NH4(+)-N, and PO4(3-)-P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L, and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively.

  9. Comparative evaluations of organic matters and nitrogen removal capacities of integrated vertical-flow constructed wetlands: Domestic and nitrified wastewater treatment.

    Science.gov (United States)

    Chang, Jun J; Liang, Kang; Wu, Su Q; Zhang, Sheng H; Liang, Wei

    2015-01-01

    Two groups of integrated vertical-flow constructed wetland (IVCW) microcosms were established for treating two types of representative wastewater: domestic and nitrified wastewater under two loading rates (LRs) over about two years. Their removal capacities of organic substance and nitrogen as well as the effects of loading rate (LR), outflow temperature and dissolved oxygen (DO) concentration were investigated and compared. Efficient chemical oxygen demand (COD) eliminations were achieved by the IVCWs, with the mass removal rates increasing linearly with the increasing LRs strongly, achieving average value of 56.07 g m(-2) d(-1) at the highest loading rate. Nevertheless, the effluent COD concentrations also increased, with the average value exceeding Class I A discharge standard (compared to DO, temperature was more crucial for nitrogen removal, and the temperature dependence coefficient for TN removal of low LR of NW was significantly greater than others.

  10. Membrane bioreactors fed with different COD/N ratio wastewater: impacts on microbial community, microbial products, and membrane fouling.

    Science.gov (United States)

    Han, Xiaomeng; Wang, Zhiwei; Ma, Jinxing; Zhu, Chaowei; Li, Yaxin; Wu, Zhichao

    2015-08-01

    It is known that an increase of COD/N ratio can result in an enhanced removal of nutrients in membrane bioreactors (MBRs); however, impacts of doing so on membrane filtration performance remain unclear. In this work, comparison of membrane filtration performance, microbial community, and microbial products under low temperature was carried out in anoxic/oxic (A/O) MBRs with COD/N ratios of 9.9 and 5.5 g COD/g N in influent. There was no doubt that an improvement of nitrogen removal under high COD/N ratio was observed; however, severer membrane fouling was found compared to the MBR fed with low COD/N ratio wastewater. The increase of COD/N ratio resulted in an elevated production of humic acids in soluble microbial product (SMP) and carbohydrates, proteins, and humic acids in loosely bound extracellular polymeric substance (LB-EPS). Quartz crystal microbalance with dissipation monitoring (QCM-D) analysis showed that the adsorption capability of SMP and LB-EPS was higher in the MBR with higher COD/N ratio. Four hundred fifty four high-throughput pyrosequencing revealed that the higher COD/N ratio led to the enrichment of Bacteroidetes at phylum level and Azospira, Thauera, Zoogloea, etc. at genus level. Bacteroidetes are considered to potentially release EPS, and Azospira, Thauera, and Zoogloea, etc. have denitrification activity. The change in microbial communities is consistent with MBR performance.

  11. The examination of the seasonal influence on the efficiency in oil and fats removal through primary treatment from the wastewater of edible oil industry

    Directory of Open Access Journals (Sweden)

    Nikolin Tatjana

    2014-01-01

    Full Text Available This paper investigates the influence of the seasonal change of the air temperature, chemical oxygen demand as well as efficiency of suspended matter removal on the efficiency of oil and fats removal (h, % during primary treatment. The parameters are monitored in the period of time from 2006 to 2011. The efficiency of oil and fats removal in the first and in the fourth quartal is proportional to the efficiency of the removal of suspended matter and of total organic matter, measured as chemical oxygen demand (COD. The measured values for oil and fat are: η (IV quartal = 0.96 % - 50.8 % and η (I quartal = 5.06 % - 95.97 %. The efficiency of oil and fats removal in the second and third quartal is proportional to air temperature so the measured efficiency of fat and oil removal are, η (II quartal = 3.93 % - 82.86 % and η (III quartal = 6.82% - 71.51%. The results of investigation have shown the existence of the correlation between the air temperature during various seasons and the efficiency of the oil and fats removal (h, % as well as the removal of the suspended matter and chemical oxygen demand (COD.

  12. Cod avoidance by area regulations in Kattegat

    DEFF Research Database (Denmark)

    Eliasen, Søren Qvist

    2014-01-01

    presents two initiatives for cod avoidance in Kattegat; a fisher initiative sharing information about cod bycatch which could lead to real time closures in areas with high bycatch of juveniles, for vessels with low cod quota to avoid catch of all cod, and a Danish Swedish Government initiative of permanent......The article examines the experiences of two initiatives of cod avoidance by area regulations in the Kattegat in the light of the upcoming discard ban in EU fisheries. The first section highlights elements of the discard ban in the reformed EU Common Fisheries Policy (CFP). The second section...... and temporary area closures in Kattegat. The third section discusses the lessons learned in the light of implementation of the discard ban. The fourth section sums up the lessons learned; Regional measures of implementation of the discard ban should include all vessels with quota in the region to be regarded...

  13. Optimization of enhanced bioelectrical reactor with electricity from microbial fuel cells for groundwater nitrate removal.

    Science.gov (United States)

    Liu, Ye; Zhang, Baogang; Tian, Caixing; Feng, Chuanping; Wang, Zhijun; Cheng, Ming; Hu, Weiwu

    2016-01-01

    Factors influencing the performance of a continual-flow bioelectrical reactor (BER) intensified by microbial fuel cells for groundwater nitrate removal, including nitrate load, carbon source and hydraulic retention time (HRT), were investigated and optimized by response surface methodology (RSM). With the target of maximum nitrate removal and minimum intermediates accumulation, nitrate load (for nitrogen) of 60.70 mg/L, chemical oxygen demand (COD) of 849.55 mg/L and HRT of 3.92 h for the BER were performed. COD was the dominant factor influencing performance of the system. Experimental results indicated the undistorted simulation and reliable optimized values. These demonstrate that RSM is an effective method to evaluate and optimize the nitrate-reducing performance of the present system and can guide mathematical models development to further promote its practical applications.

  14. Anaerobic co-digestion cassava wastewater and crude glycerin for removal of COD and solid; Co-digestao anaerobica de manipueira e glicerina bruta para remocao de DQO e solidos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jefferson L.G.; Guerra Junior, Joao B. [Universidade Estadual do Oeste do Parana (UNIOESTE), Cascavel, PR (Brazil)], E-mail: j.lg11@yahoo.com.br; Gomes, Simone D.; Mallmann, Larissa S. [Universidade Estadual do Oeste do Parana (CCET/PGEAGRI/UNIOESTE), Cascavel, PR (Brazil). Dept. de Recursos Hidricos e Saneamento Ambiental

    2012-11-01

    To be discarded into the environment, cassava wastewater, generated during the processing of the cassava root, needs to be dealt with trying to reduce its organic load and total solids, harmful to water bodies. As for crude glycerin, a byproduct of biodiesel production, need alternatives to its destination, because the cost to its purification is often not feasible, preventing its use by pharmaceutical and food industries. In this study we chose to anaerobic digestion to treat manipueira assessing the behavior of the reactor with the addition of glycerin. The reactor was constructed of PVC with 60cm long, 20cm in diameter and a volume of 8.38 L, and HRT was 5 days. Three treatments were applied: T1, only manipueira, T2 with 0.25% glycerol and T3, with 0.50%. The three treatments showed a great reduction of organic load (above 90%) and higher with the addition of 0.25% crude glycerine. The highest mean removal of solids and total volatile solids occurred in treatment with 0.50% crude glycerine, being 84.18% and 91.41% respectively. (author)

  15. AFSC/REFM: Pacific cod Localized Depletion Study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data from Localized Depletion study for Pacific cod 2001-2005. Study was conducted using cod pot gear to measure localized abundance of Pacific cod inside and...

  16. Modeling simultaneous carbon and nitrogen removal (SCNR) in anaerobic/anoxic reactor treating domestic wastewater.

    Science.gov (United States)

    Mendes, Carlos; Esquerre, Karla; Queiroz, Luciano Matos

    2016-07-15

    This paper presents a mathematical model based on the Anaerobic Digestion Model No. 1 (ADM1) to simulate the effects of nitrate concentration and hydraulic retention time (HRT) on the simultaneous carbon and nitrogen removal (SCNR) in anaerobic/anoxic reactor treating domestic wastewater. The model was calibrated using previously published experimental data obtained from anaerobic batch tests for different COD/ [Formula: see text] ratios. Model simulations were performed to predict the SCNR in a completely mixed reactor (CSTR) operating under mesophilic conditions (35 °C). Six different scenarios were evaluated to investigate the performance of the SCNR based on typical influent characteristics of domestic wastewater. The variables analyzed were chemical oxygen demand (COD) removal, nitrate concentration, methane production, nitrogen gas, volatile fatty acids (VFA) concentration, pH and percentage of COD used by the denitrifying and methanogenic microorganisms. The HRT was decreased stepwise from 15 to 4 h. The results indicate that Scenario (S5) with a COD/ [Formula: see text] ratio equal to 10 and an HRT equal to 15 h ensures the occurrence of the stable SCNR. Furthermore, the accumulation of denitrification intermediates and a significant reduction in the biogas production when the organic matter is limited was verified.

  17. Enhancing organic matter removal, biopolymer recovery and electricity generation from distillery wastewater by combining fungal fermentation and microbial fuel cell.

    Science.gov (United States)

    Ghosh Ray, S; Ghangrekar, M M

    2015-01-01

    For enhancing organic matter removal from cereal-based distillery stillage two-stage treatment consisting of fermentation by Aspergillus awamori followed by microbial fuel cell (MFC) is proposed. Considerable reduction in total and soluble chemical oxygen demand (COD) up to 70% and 40%, respectively, along with 98% reduction of suspended solids (SS) has been achieved during fungal pretreatment. The process generated chitosan, a useful fermentation byproduct from fungal mycelia, as 0.6-0.7g/l of settled sludge with mycelium (3.8% solids). Prior treatment of wastewater with fungal strain enhanced the power generation in MFC by 2.9 times at an organic loading rate of 1.5kgCOD/m(3)day, demonstrating soluble COD reduction of 92% in MFC. While treating distillery wastewater, this two-stage integrated biological process demonstrated overall 99% COD removal and almost complete removal of SS, delivering ample scope for scale-up and industrial application to offer effective solution for distillery wastewater treatment.

  18. Nitrogen removal from coal gasification wastewater by activated carbon technologies combined with short-cut nitrogen removal process.

    Science.gov (United States)

    Zhao, Qian; Han, Hongjun; Hou, Baolin; Zhuang, Haifeng; Jia, Shengyong; Fang, Fang

    2014-11-01

    A system combining granular activated carbon and powdered activated carbon technologies along with shortcut biological nitrogen removal (GAC-PACT-SBNR) was developed to enhance total nitrogen (TN) removal for anaerobically treated coal gasification wastewater with less need for external carbon resources. The TN removal efficiency in SBNR was significantly improved by introducing the effluent from the GAC process into SBNR during the anoxic stage, with removal percentage increasing from 43.8%-49.6% to 68.8%-75.8%. However, the TN removal rate decreased with the progressive deterioration of GAC adsorption. After adding activated sludge to the GAC compartment, the granular carbon had a longer service-life and the demand for external carbon resources became lower. Eventually, the TN removal rate in SBNR was almost constant at approx. 43.3%, as compared to approx. 20.0% before seeding with sludge. In addition, the production of some alkalinity during the denitrification resulted in a net savings in alkalinity requirements for the nitrification reaction and refractory chemical oxygen demand (COD) degradation by autotrophic bacteria in SBNR under oxic conditions. PACT showed excellent resilience to increasing organic loadings. The microbial community analysis revealed that the PACT had a greater variety of bacterial taxons and the dominant species associated with the three compartments were in good agreement with the removal of typical pollutants. The study demonstrated that pre-adsorption by the GAC-sludge process could be a technically and economically feasible method to enhance TN removal in coal gasification wastewater (CGW).

  19. PENURUNAN BOD DAN COD LIMBAH CAIR INDUSTRI TEKSTIL DI KABUPATEN PEKALONGAN DENGAN METODE MULTI SOIL LAYERING

    Directory of Open Access Journals (Sweden)

    Irmanto

    2008-11-01

    Full Text Available Multi Soil Layering (MSL system is a method of wastewater treatment that increase the soils function to purify wastewater. In the construction of MSL, soils mixed with the charcoal and then filled into the box of size 50x14x50 cm in layers structured like brick pattern. The aims of this research are to determine the concentration of BOD and COD on textile industrial wastewater before and after the process by MSL method. It also determines the optimal loading rate of wastewater on the MSL system, and then it can determine the efficiency of MSL system on reducing the concentration of BOD and COD on textile industrial wastewater. The method which used in this research is an experimental method. The wastewater on the MSL system is loaded on the loading rate variety: 160, 320, 480, 640, and 800 L m-2 day-1. The efficiency of MSL system to removing BOD and COD on textile industrial wastewater are determined on optimal loading rate. The research gave result that MSL method could remove BOD and COD on textile industrial wastewater on the optimal loading rate 320 L m-2 day-1. The efficiency of MSL system in removing BOD and COD on textile industrial wastewater are 96.52 and 80.87% respectively. This indicated that the method MSL serve the purpose of effective alternative method in processing of liquid waste textile industry.

  20. Simultaneous removal of nitrogen and phosphorus from swine wastewater in a sequencing batch biofilm reactor

    Institute of Scientific and Technical Information of China (English)

    Reti Hai; Yiqun He; Xiaohui Wang; Yuan Li

    2015-01-01

    In this study, the performance of a sequencing batch biofilm reactor (SBBR) for removal of nitrogen and phosphorus from swine wastewater was evaluated. The replacement rate of wastewater was set at 12.5%throughout the exper-iment. The anaerobic and aerobic times were 3 h and 7 h, respectively, and the dissolved oxygen concentration of the aerobic phase was about 3.95 mg·L−1. The SBBR process demonstrated good performance in treating swine wastewater. The percentage removal of total chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) was 98.2%, 95.7%, 95.6%, and 96.2%at effluent concentrations of COD 85.6 mg·L−1, NH4+-N 35.22 mg·L−1, TN 44.64 mg·L−1, and TP 1.13 mg·L−1, respectively. Simultaneous nitrification and denitrification phenomenon was observed. Further improvement in removal efficiency of NH4+-N and TN occurred at COD/TN ratio of 11:1, with effluent concentrations at NH4+-N 18.5 mg·L−1 and TN 34 mg·L−1, while no such improvement in COD and TP removal was found. Microbial electron microscopy analysis showed that the fil er surface was covered with a thick biofilm, forming an anaerobic–aerobic microenvironment and facilitating the removal of nitrogen, phosphorus and organic matters. A long-term experiment (15 weeks) showed that stable removal efficiency for N and P could be achieved in the SBBR system.

  1. The Performance of Advanced Sequencing Batch Reactor in Wastewater Treatment Plant to Remove Organic Materials and Linear Alkyl Benzene Sulfonates

    Directory of Open Access Journals (Sweden)

    Eslami

    2015-07-01

    Full Text Available Background Linear alkyl benzene sulfonates (LAS are the most important ionic detergents that produce negative ions in the environment. These compounds enter surface waters through domestic and industrial wastewaters and cause environmental hazards. Objectives The present study was aimed at assessing the performance of advanced sequencing batch reactor (SBR in wastewater treatment plant of Yazd, Iran, to remove organic materials and detergents. Materials and Methods The present research was a descriptive longitudinal study conducted on 96 input and output samples of SBR system over eight months from October 2012 to June 2013. The studied parameters were biochemical oxygen demand 5 (BOD5, chemical oxygen demand (COD, and detergents (LAS, which were assessed through standard methods. Finally, the study data were analyzed through analysis of variance (ANOVA using software package for statistical analysis (SPSS. Results The mean inputs of BOD5, COD, and LAS to the SBR system were 292.40 ± 45.28, 597.15 ± 97.30, and 3.29 ± 0.92 mg/L, and the mean outputs were 20.59 ± 3.54, 59.34 ± 9.47, and 0.606 ± 0.09 mg/L, respectively. The removal efficiency of BOD5, COD and LAS were respectively 92.95%, 90.06% and 81.6%. The results of ANOVA indicated that there was a significant relationship between the mean inputs and outputs of BOD5, COD, and the detergents (P ≤ 0.001. Conclusions With the proper operation of wastewater the treatment plant and increasing the retention time, the removal efficiency of the detergents increased. In addition, according to the environmental standards for BOD5, COD and the detergents, the results of the present study indicated that the outputs of these parameters from the SBR system were appropriate for agricultural irrigation.

  2. The impacts of turbidity for COD measurements using UV-Vis spectrometry and compensation method (Conference Presentation)

    Science.gov (United States)

    Wen, Yizhang; Hu, Yingtian; Wang, Xiaoping

    2016-09-01

    Ultraviolet absorption spectroscopy is one of physical methods used for chemical oxygen demand (COD) measurements of water. The absorbances in ultraviolet band have a relationship to COD. However, turbidity in water could scatter emitting light and influence the absorbances. So it is very important to compensate for the impact of turbidity. In this study, the absorption spectra of standard COD solution (potassium acid phthalate), turbidity solution (Formazine) and their mixture are sampled in the wavelength range from 220 to 750 nm. The impacts of turbidity for COD measurement and compensation method are studied based on these data. The absorbance of mixture substract the absorbance of turbidity solution is less than the absorbance of standard COD solution. The result indicates that turbidity particles decrease the light absorption of organic molecules. Furthermore, we discover that the impact of turbidity is greater for the larger absorbance of the standard COD solution. Then attenuation coeffcient (AC()) is introduced and calculated based on exprimental results. In the process of turbidity compensation, the turbidity of solution is estimated using the absorbance of visible wavelength. The absorption spectra of the turbidity in the ultraviolet wavelength are simulated using normalization technique. The satisfactory prediction result of COD is achieved for the mixture after the turbidity compensation. In conclusion, the new turbidity compensation method could eliminate the influence of turbidity for COD measurements based on absorption spectroscopy.

  3. Removal of Cu(II) ions by biosorption onto powdered waste sludge (PWS) prior to biological treatment in an activated sludge unit: a statistical design approach.

    Science.gov (United States)

    Pamukoglu, M Yunus; Kargi, Fikret

    2009-04-01

    Biological treatment of synthetic wastewater containing Cu(II) ions was realized in an activated sludge unit with pre-adsorption of Cu(II) onto powdered waste sludge (PWS). Box-Behnken experimental design method was used to investigate Cu(II), chemical oxygen demand (COD) and toxicity removal performance of the activated sludge unit under different operating conditions. The independent variables were the solids retention time (SRT, 5-30 d), hydraulic residence time (HRT, 5-25 h), feed Cu(II) concentration (0-50 mg L(-1)) and PWS loading rate (0-4 g h(-1)) while percent Cu(II), COD, toxicity (TOX) removals and the sludge volume index (SVI) were the objective functions. The data were correlated with a quadratic response function (R2=0.99). Cu(II), COD and toxicity removals increased with increasing PWS loading rate and SRT while decreasing with the increasing feed Cu(II) concentration and HRT. Optimum conditions resulting in maximum Cu(II), COD, toxicity removals and SVI values were found to be SRT of 30 d, HRT 15 h, PWS loading rate 3 g h(-1) and feed Cu(II) concentration of less than 30 mg L(-1).

  4. Relationships between water quality parameters in rivers and lakes: BOD5, COD, NBOPs, and TOC.

    Science.gov (United States)

    Lee, Jaewoong; Lee, Seunghyun; Yu, Soonju; Rhew, Doughee

    2016-04-01

    Biological oxygen demand (BOD5) or chemical oxygen demand (COD) analysis is widely used to evaluate organic pollutants in water systems as well as the efficiency of wastewater treatment plants. However, both analysis methods have restrictions such as being insensitive, imprecise, time-consuming, and the production of chemical waste. Therefore, total organic carbon (TOC) analysis for organic pollutants has been considered for an alternative analysis instead of BOD5 or COD. Several studies have investigated the replacement of BOD5 or COD with TOC in wastewater samples; however, few studies have investigated the relationships between water quality parameters in rivers and lakes. Therefore, this study evaluated the relationships between BOD5, COD, or NBOPs and TOC by the analysis of national water quality monitoring data of rivers and lakes for 5 years. High correlation coefficients (r) of 0.87 and 0.66 between BOD5 and TOC (p TOC (p TOC was 0.93 for rivers and 0.72 for lakes. The coefficients of determination (R 2) were 0.75 and 0.44 between BOD5 and TOC for rivers and lakes as well as were 0.87 and 0.57 between COD and TOC for rivers and lakes, respectively. The coefficient of determination (R 2) between NBOPs and TOC was 0.73 for rivers and 0.52 for lakes.

  5. Combined coagulation-flocculation and sequencing batch reactor with phosphorus adjustment for the treatment of high-strength landfill leachate: experimental kinetics and chemical oxygen demand fractionation.

    Science.gov (United States)

    El-Fadel, M; Matar, F; Hashisho, J

    2013-05-01

    The treatability of high-strength landfill leachate is challenging and relatively limited. This study examines the feasibility of treating high-strength landfill leachate (chemical oxygen demand [COD]: 7,760-11,770 mg/L, biochemical oxygen demand [BOD5]: 2,760-3,569 mg/L, total nitrogen [TN] = 980-1,160 mg/L) using a sequencing batch reactor (SBR) preceded by a coagulation-flocculation process with phosphorus nutritional balance under various mixing and aeration patterns. Simulations were also conducted to define kinetic parameters and COD fractionation. Removal efficiencies reached 89% for BOD5, 60% for COD, and 72% for TN, similar to and better than reported studies, albeit with a relatively lower hydraulic retention time (HRT) and solid retention time (SRT). The coupled experimental and simulation results contribute in filling a gap toward managing high-strength landfill leachate and providing guidelines for corresponding SBR applications. The treatability of high-strength landfill leachate, which is challenging and relatively limited, was demonstrated using a combined coagulation-flocculation with SBR technology and nutrient balance adjustment. The most suitable coagulant, kinetic design parameters, and COD fractionation were defined using coupled experimental and simulation results contributing in filling a gap toward managing high-strength leachate by providing guidelines for corresponding SBR applications and anticipating potential constraints related to the non-biodegradable COD fraction. In this context, while the combined coagulation-flocculation and SBR process improved removal efficiencies, posttreatment may be required for high-strength leachate, depending on discharge standards and ultimate usage of the treated leachate.

  6. Trophodynamic control on recruitment success in Baltic cod : the influence of cannibalism

    DEFF Research Database (Denmark)

    Neuenfeldt, Stefan; Köster, Fritz

    2000-01-01

    Cod is the top piscivore predator in the Baltic Sea ecosystem. Based on stomach content data from 62427 cod collected during 1977-1994 and food consumption rates, cannibalism in the Eastern and Western Baltic cod stocks has been quantified using multispecies virtual population analysis. In the Ea......Cod is the top piscivore predator in the Baltic Sea ecosystem. Based on stomach content data from 62427 cod collected during 1977-1994 and food consumption rates, cannibalism in the Eastern and Western Baltic cod stocks has been quantified using multispecies virtual population analysis....... In the Eastern Baltic stock, depending on model assumptions, an average of 25-38% of the 0-group and 11-17% of the 1-group were removed by predation by adults. Thus, between age 0 and age 2 a year class may lose on average about 31% and 44% of the initial number as a result of cannibalism. Cannibalism is lower...... in the Western Baltic. On average, 19% of the 0-group and 9% of the 1-group are consumed per year, i.e. 24% of the initial cohort is eaten before reaching age 2. Predation was most intense in 1978-1984, a period with high juvenile abundance and large adult stock sizes in both areas. Subsequently, stock...

  7. EAARL Topography-Cape Cod National Seashore

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Elevation maps (also known as Digital Elevation Models or DEMs) of Cape Cod National Seashore were produced from remotely-sensed, geographically-referenced elevation...

  8. EAARL Topography-Cape Cod National Seashore

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Elevation maps (also known as Digital Elevation Models or DEMs) of Cape Cod National Seashore were produced from remotely-sensed, geographically-referenced elevation...

  9. EAARL Topography-Cape Cod National Seashore

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Elevation maps (also known as Digital Elevation Models or DEMs) of Cape Cod National Seashore were produced from remotely-sensed, geographically-referenced...

  10. Who's your mama? Riverine hybridisation of threatened freshwater Trout Cod and Murray Cod.

    Science.gov (United States)

    Couch, Alan J; Unmack, Peter J; Dyer, Fiona J; Lintermans, Mark

    2016-01-01

    Rates of hybridization and introgression are increasing dramatically worldwide because of translocations, restocking of organisms and habitat modifications; thus, determining whether hybridization is occuring after reintroducing extirpated congeneric species is commensurately important for conservation. Restocking programs are sometimes criticized because of the genetic consequences of hatchery-bred fish breeding with wild populations. These concerns are important to conservation restocking programs, including those from the Australian freshwater fish family, Percichthyidae. Two of the better known Australian Percichthyidae are the Murray Cod, Maccullochella peelii and Trout Cod, Maccullochella macquariensis which were formerly widespread over the Murray Darling Basin. In much of the Murrumbidgee River, Trout Cod and Murray Cod were sympatric until the late 1970s when Trout Cod were extirpated. Here we use genetic single nucleotide polymorphism (SNP) data together with mitochondrial sequences to examine hybridization and introgression between Murray Cod and Trout Cod in the upper Murrumbidgee River and consider implications for restocking programs. We have confirmed restocked riverine Trout Cod reproducing, but only as inter-specific matings, in the wild. We detected hybrid Trout Cod-Murray Cod in the Upper Murrumbidgee, recording the first hybrid larvae in the wild. Although hybrid larvae, juveniles and adults have been recorded in hatcheries and impoundments, and hybrid adults have been recorded in rivers previously, this is the first time fertile F1 have been recorded in a wild riverine population. The F1 backcrosses with Murray cod have also been found to be fertile. All backcrosses noted were with pure Murray Cod. Such introgression has not been recorded previously in these two species, and the imbalance in hybridization direction may have important implications for restocking programs.

  11. Biological removal of phenol from saline wastewater using a moving bed biofilm reactor containing acclimated mixed consortia.

    Science.gov (United States)

    Nakhli, Seyyed Ali Akbar; Ahmadizadeh, Kimia; Fereshtehnejad, Mahmood; Rostami, Mohammad Hossein; Safari, Mojtaba; Borghei, Seyyed Mehdi

    2014-01-01

    In this study, the performance of an aerobic moving bed biofilm reactor (MBBR) was assessed for the removal of phenol as the sole substrate from saline wastewater. The effect of several parameters namely inlet phenol concentration (200-1200 mg/L), hydraulic retention time (8-24 h), inlet salt content (10-70 g/L), phenol shock loading, hydraulic shock loading and salt shock loading on the performance of the 10 L MBBR inoculated with a mixed culture of active biomass gradually acclimated to phenol and salt were evaluated in terms of phenol and chemical oxygen demand (COD) removal efficiencies. The results indicated that phenol and COD removal efficiencies are affected by HRT, phenol and salt concentration in the bioreactor saline feed. The MBBR could remove up to 99% of phenol and COD from the feed saline wastewater at inlet phenol concentrations up to 800 mg/L, HRT of 18 h and inlet salt contents up to 40 g/L. The reactor could also resist strong shock loads. Furthermore, measuring biological quantitative parameters indicated that the biofilm plays a main role in phenol removal. Overall, the results of this investigation revealed that the developed MBBR system with high concentration of the active mixed biomass can play a prominent role in order to treat saline wastewaters containing phenol in industrial applications as a very efficient and flexible technology.

  12. Performance Characteristics for Nitrogen Removal in SBR by Aerobic Granules%SBR好氧污泥颗粒的脱氮性能研究

    Institute of Scientific and Technical Information of China (English)

    刘其杰; 胡翔; 王建龙

    2005-01-01

    The sequencing batch reactor (SBR) was started up by seeding the anaerobic granular sludge and the aerobic granular sludge was successfully cultivated. The performance characteristic of the aerobic granules for nitrogen removal was investigated in detail. The experimental results demonstrated the relationship between operational parameters [dissolved oxygen (DO) and pH] and variation of chemical oxygen demand (COD), ammonium (NH4+-N)and total nitrogen (TN). In continuous flow pattern, COD was too low in the reactor at the later stage of a cycle,which restrained denitrification and decreased the removal of nitrogen, while in discontinuous flow pattern, the carbon source could be supplemented in time, which improved denitrification and increased the removal of TN from 66% to 81%.

  13. Sulfamethoxazole and COD increase abundance of sulfonamide resistance genes and change bacterial community structures within sequencing batch reactors.

    Science.gov (United States)

    Guo, Xueping; Pang, Weihai; Dou, Chunling; Yin, Daqiang

    2017-05-01

    The abundant microbial community in biological treatment processes in wastewater treatment plants (WWTPs) may potentially enhance the horizontal gene transfer of antibiotic resistance genes with the presence of antibiotics. A lab-scale sequencing batch reactor was designed to investigate response of sulfonamide resistance genes (sulI, sulII) and bacterial communities to various concentrations of sulfamethoxazole (SMX) and chemical oxygen demand (COD) of wastewater. The SMX concentrations (0.001 mg/L, 0.1 mg/L and 10 mg/L) decreased with treatment time and higher SMX level was more difficult to remove. The presence of SMX also significantly reduced the removal efficiency of ammonia nitrogen, affecting the normal function of WWTPs. All three concentrations of SMX raised both sulI and sulII genes with higher concentrations exhibiting greater increases. The abundance of sul genes was positive correlated with treatment time and followed the second-order reaction kinetic model. Interestingly, these two genes have rather similar activity. SulI and sulII gene abundance also performed similar response to COD. Simpson index and Shannon-Weiner index did not show changes in the microbial community diversity. However, the 16S rRNA gene cloning and sequencing results showed the bacterial community structures varied during different stages. The results demonstrated that influent antibiotics into WWTPs may facilitate selection of ARGs and affect the wastewater conventional treatment as well as the bacteria community structures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Who’s your mama? Riverine hybridisation of threatened freshwater Trout Cod and Murray Cod

    Science.gov (United States)

    Unmack, Peter J.; Dyer, Fiona J.; Lintermans, Mark

    2016-01-01

    Rates of hybridization and introgression are increasing dramatically worldwide because of translocations, restocking of organisms and habitat modifications; thus, determining whether hybridization is occuring after reintroducing extirpated congeneric species is commensurately important for conservation. Restocking programs are sometimes criticized because of the genetic consequences of hatchery-bred fish breeding with wild populations. These concerns are important to conservation restocking programs, including those from the Australian freshwater fish family, Percichthyidae. Two of the better known Australian Percichthyidae are the Murray Cod, Maccullochella peelii and Trout Cod, Maccullochella macquariensis which were formerly widespread over the Murray Darling Basin. In much of the Murrumbidgee River, Trout Cod and Murray Cod were sympatric until the late 1970s when Trout Cod were extirpated. Here we use genetic single nucleotide polymorphism (SNP) data together with mitochondrial sequences to examine hybridization and introgression between Murray Cod and Trout Cod in the upper Murrumbidgee River and consider implications for restocking programs. We have confirmed restocked riverine Trout Cod reproducing, but only as inter-specific matings, in the wild. We detected hybrid Trout Cod–Murray Cod in the Upper Murrumbidgee, recording the first hybrid larvae in the wild. Although hybrid larvae, juveniles and adults have been recorded in hatcheries and impoundments, and hybrid adults have been recorded in rivers previously, this is the first time fertile F1 have been recorded in a wild riverine population. The F1 backcrosses with Murray cod have also been found to be fertile. All backcrosses noted were with pure Murray Cod. Such introgression has not been recorded previously in these two species, and the imbalance in hybridization direction may have important implications for restocking programs.

  15. Where does the cod come from? Panels of gene‐associated markers provide vastly improved origin assignment in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Eg Nielsen, Einar; Hansen, Jakob Hemmer; Taylor, Martin

    2012-01-01

    Methods for determining the geographical origin of individual fish are in high demand for fighting illegal, unreported, and unregulated (IUU) fishing and for independent control of catch certificates and “eco‐labels”. Hitherto, genetic origin assignment of marine fish has been hampered...... relevant for controlling illegal fishing, ecolabels, and fisheries management. Our results demonstrate how application of gene‐associated markers will probably revolutionize origin assignment in cod by providing faster, cheaper, and more reliable tools for origin assignment...

  16. Study on Migration and Transformation Rule of Organic Pollutants (COD) in Aerated Zone

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Collecting waste water with a certain concentration of organic pollutants COD (chemical oxygen demand), static adsorption, static biodegradation and dynamic soil column experiments were made in laboratory, we researched migration and transformation of COD in aerated zone, and put forward a mathematical model showing the process. The results show that adsorption of organism in aerated zone is linear, which is represented by Henry's law s=Kdc+sd, adsorption coefficient Kd =0. 069 3;biodegradation diagram accord basically with first-order kinetics equation c=c0e-K1t , biodegradation coefficient K1 = 0. 049 9 d-1; dispersion coefficient D= 0. 002 42 m2/d in experiments. The migration and transformation of organic pollutants (COD) in aerated zone jointly result from many factors such as dispersion, adsorption and biodegradation etc..

  17. Removal of organic load and suspended solids from water by electrocoagulation method

    Directory of Open Access Journals (Sweden)

    Ilie Pisoi

    2011-08-01

    Full Text Available Electrocoagulation (EC is an electrochemical technique involving in-situ generation ofcoagulation agents from sacrificial anodes by type of aluminium and iron. In the present study EC hasbeen evaluated as a treatment technology for organic load and suspended solids removal from a realwastewater proceeded from pulp and paper industry, which was characterized by high content of organicload and suspended solids. The efficiency of the electrocoagulation process was assessed by monitoringChemical Oxygen Demand (COD and suspended solids (s.s. parameters. Laboratory- scale experimentswere conducted with aluminum anode to assess its efficiency under galvanostatic regime. To establishthe optimum operational parameter selected as current density, the electrolysis was carried out at 50,100 and 200 Am-2. The electrocoagulation process performance was assessed based on the efficiencies ofCOD and s.s. removal correlated with the specific electrical energy consumption. Applying EC processallowed to achieve the COD removal efficiencies ranged between 83.80 and 94.00 % and s.s. removalefficiencies between 87.77 and 95.47 %.

  18. Nitrogen removal in a combined system: vertical vegetated bed over horizontal flow sand bed.

    Science.gov (United States)

    Kantawanichkul, S; Neamkam, P; Shutes, R B

    2001-01-01

    Pig farm wastewater creates various problems in many areas throughout Thailand. Constructed wetland systems are an appropriate, low cost treatment option for tropical countries such as Thailand. In this study, a combined system (a vertical flow bed planted with Cyperus flabelliformis over a horizontal flow sand bed without plants) was used to treat settled pig farm wastewater. This system is suitable for using in farms where land is limited. The average COD and nitrogen loading rate of the vegetated vertical flow bed were 105 g/m2 x d and 11 g/m2 x d respectively. The wastewater was fed intermittently at intervals of 4 hours with a hydraulic loading rate of 3.7 cm/d. The recirculation of the effluent increased total nitrogen (TN) removal efficiency from 71% to 85%. The chemical oxygen demand (COD) and total Kjeldahl nitrogen (TKN) removal efficiencies were 95% and 98%. Nitrification was significant in vertical flow Cyperus bed, and the concentration of nitrate increased by a factor of 140. The horizontal flow sand bed enhanced COD removal and nitrate reduction was 60%. Plant uptake of nitrogen was 1.1 g N/m2 x d or dry biomass production was 2.8 kg/m2 over 100 days.

  19. Walking the cod: an investigation into the relative robustness of cod, Gadus morhua, skeletal elements

    Directory of Open Access Journals (Sweden)

    Andrew K.G. Jones

    1999-12-01

    Full Text Available A simple experiment is described which details what happens to the bones of cod when they are walked on by a man. The pattern of fragmentation for various elements is illustrated and an index of robustness proposed for those elements in a cod skeleton most frequently recovered from archaeological sites.

  20. Removal of organic matter from H2TaF7 solution by adsorption

    Institute of Scientific and Technical Information of China (English)

    LI Qing-gang; ZHOU Kang-gen; ZHANG Qi-xiu

    2005-01-01

    The removal of organic matter from H2TaF7 solution by adsorption was investigated in order to reduce the carbon content in the K2TaF7 crystal. Three kinds of adsorbent, LSA-5 resin, LSA-20 resin and active carbon were applied in the fixed bed respectively. Experimental results indicate that LAS-5 resin, LAS-20 resin, the mixture of LAS-5 resin and LAS-20 resin(with volume ratio of 1∶1), and the active carbon can all reduce chemical oxygen demand(COD) value of the H2TaF7 solution, and reduce consequently carbon content of K2TaF7 crystal to 0.001 0%0.001 5% from 0.002 5%0.003 0%. Comparing with the others, the active carbon is an approved adsorbent whose bed volumes of effluent reaches 70. In addition, there is a linear relationship between the COD value of H2TaF7 solution and the carbon content in K2TaF7 crystal, and the carbon content in K2TaF7 crystal decreases with the decreasing of COD value of H2TaF7 solution. When the COD value of H2TaF7 solution is lower than 7 mg/L, the carbon content in K2TaF7 crystal would decrease to less than 0.001 5%.

  1. Energy Demand

    NARCIS (Netherlands)

    Stehfest, E. et al.

    2014-01-01

    Key policy issues – How will energy demand evolve particularly in emerging and medium- and low- income economies? – What is the mix of end-use energy carriers to meet future energy demand? – How can energy efficiency contribute to reducing the growth rate of energy demand and mitigate pressures on t

  2. 交替缺氧/好氧CAST处理低pCOD/pTN生活污水的脱氮研究%Biological Nitrogen Removal by Alternating Anoxic/aerobic CAST Treating Municipal Wastewater With a Low pCOD/pTN Ratio

    Institute of Scientific and Technical Information of China (English)

    彭永臻; 王丽; 马娟; 王少坡; 刘洋; 马宁平

    2012-01-01

    以低pCOD/pTN生活污水为处理对象,在连续和分段2种进水方式下分析了交替缺氧/好氧循环式活性污泥法工艺的脱氮性能及曝气需求量,并研究了分段进水方式下pH、PDO和氧化还原电位(oxidation reduction potential,ORP)的变化规律.结果表明,连续进水方式下,系统TN平均去除率75.1%,系统因长期低负荷运行而发生污泥膨胀,污泥容积指数(sludge volume index,SVD平均值为229mL/g,同时,曝气量升至0.56m^3/h时,才能使NH4^+-N去除率大于99%;采用分段进水方式时,系统TN平均去除率可提高至81.5%,污泥沉降性能良好,并且曝气量降至0.24m^3/h时,系统NH4^+-N去除率仍大于99%,节省了运行费用.此外,当采用分段进水时,反应区内的pH值、pDO和ORP值曲线有较明显的变化规律,并与反应区内污染物浓度的变化有着较好的相关性。%Abstract: This study investigates the effects of continuous-feeding and step-feeding patterns on the nitrogen removal performance and the aeration rate under the anoxic/aerobic (A/O) condition of cyclicactivated sludge technology (CAST) process treating low pCOD/pTN wastewater, and analyzes the profiles of pH, DO and ORP under the step-feed mode. Results show that the average removal rate of pTN is75. 1% and SVI is 229 mL/g when the system runs under the continuous feeding mode, and activated sludge bulking occurs because of the operation under long-term condition of a low influent load. However, the average removal rate of pTN increases to 81. 5% and the average SVI decreases when thesystem runs under the step-feeding mode. Meanwhile, the aeration rate of the continuous-feeding mode is0.56 m^3/h but 0.24 m^3/h under the step-feeding mode when the removal rate of p ( NH4^+-N) is above99%. Consequently, the operation cost can be significantly reduced by using the step-feeding mode. Furthermore, pH, DO

  3. Ferrous ion-activated persulphate process for landfill leachate treatment: removal of organic load, phenolic micropollutants and nitrogen.

    Science.gov (United States)

    Kattel, Eneliis; Dulova, Niina

    2017-05-01

    The innovative [Formula: see text] treatment technology based on sulphate radicals induced oxidation was applied for the treatment of landfill leachate. The performance of chemical oxygen demand (COD) and dissolved organic carbon (DOC) removal in the Fe(2+)-activated persulphate system was moderate; however, the results of dissolved nitrogen (DN) and total phenols removal showed significant efficacy (≤39% and ≥87%, respectively). [Formula: see text] addition to the [Formula: see text] system enhanced the treatment efficacy and resulted in supplementary 15% of COD and 5% of DN removal. Hydroxyl radical-based H2O2/Fe(2+) treatment of the landfill leachate was performed as well; the results indicated higher removal efficacy of COD and DOC compared to the [Formula: see text] system. However, practical application of the H2O2/Fe(2+) system is considerably influenced by temperature rise and excessive foam formation. Generally, the ferrous ion-activated persulphate treatment could be a promising technology for ex situ as well as in situ landfill leachate treatment applications.

  4. COD FRACTIONS IN THE PROCESS OF MECHANICAL-BIOLOGICAL TREATMENT SEWAGE

    Directory of Open Access Journals (Sweden)

    Joanna Smyk

    2015-11-01

    Full Text Available The aim of the research was to determine the COD fraction thereof in sewage and their changes in the effluent after further treatment processes. The study was conducted in a sewage treatment plant in Bialystok (RLM> 100000. In sewage the highest concentrations occurred in the suspension of the organic fractions slowly biodegradable XS (303.7 mg O2/l and dissolved organic compounds readily biodegradable SS (263 mg O2/l. The lower amounts were irreducible fractions dissolved in sewage and suspended SI (56 mg O2/l and XI (101.2 mg O2/l. Almost 80% of the total COD fractions were biodegradable (SS + XS. In the treated wastewater soluble fraction SI-biodegradable (56 mg O2/l occurred in the highest concentration. The flow of wastewater by components of sewage treatment plant resulted the complete removal of biologically degradable fraction of dissolved SS. More than 94.5% of the total COD in waste water purified fractions were biologically decomposable (SI + XI. Moreover, based on the analysis of studies the following soil removal was found: BOD5 – 99.4%, COD – 92.9%, total nitrogen – 93.4%, total phosphorus – 92%. After waste water treatment, ammonia nitrogen was completely removed while the nitrate concentration increased to 4.6 mg N/dm3.

  5. Removal of dicyclohexyl acetic acid from aqueous solution using ultrasound, ozone and their combination.

    Science.gov (United States)

    Kumar, Pardeep; Headley, John; Peru, Kerry; Bailey, Jon; Dalai, Ajay

    2014-01-01

    Naphthenic acids are a complex mixture of organic components, some of which include saturated alkyl-substituted cycloaliphatic carboxylic acids and acyclic aliphatic acids. They are naturally found in hydrocarbon deposits like oil sand, petroleum, bitumen and crude oil. In this study, the oxidation of a relatively high molecular weight naphthenic acid (Dicyclohexyl acetic acid) was investigated using ozonation, ultrasonication and hydrogen peroxide alone and their combinations. Effects on oxidation of dicyclohexyl acetic acid (DAA) were measured for different concentrations of ozone ranging between 0.7 to 3.3 mg L(-1) and pH in the range 6 to 10. Ultrasonication and hydrogen peroxide alone were not effective to oxidize dicyclohexyl acetic acid, but combining ultrasonication with H2O2 had a significant effect on oxidation of dicyclohexyl acetic acid with maximum removal reaching to 84 ± 2.2% with 81 ± 2.1% reduction in chemical oxygen demand (COD). Synergistic effects were observed for combining ultrasonication with ozonation and resulted in 100% DAA removal with 98 ± 0.8% reduction in COD within 15 min at 3.3 mg L(-1) ozone concentration and 130 Watts ultrasonication power. The reaction conditions obtained for the maximum oxidation of DAA and COD removal were used for the degradation of naphthenic acids mixture extracted from oil sands process water (OSPW). The percentage oxidation of NAs mixture extracted from OSPW was 89.3 ± 1.1% in ozonation and combined ozonation and ultrasonication, but COD removal observed was 65 ± 1.2% and 78 ± 1.4% for ozonation and combined ozonation and ultrasonication treatments, respectively.

  6. Removal of nutrients and veterinary antibiotics from swine wastewater by a constructed macrophyte floating bed system.

    Science.gov (United States)

    Xian, Qiming; Hu, Lixia; Chen, Hancheng; Chang, Zhizhou; Zou, Huixian

    2010-12-01

    The potential of three varieties of Italian ryegrass (Lolium multiflorum Lam.), Dryan, Tachimasari and Waseyutaka, to improve the water quality of swine wastewater was evaluated using a constructed macrophyte floating bed system. With respect to reductions in levels of nutrients, chemical oxygen demand (COD), and sulfonamide antimicrobials (SAs, including sulfadiazine, sulfamethazine, and sulfamethoxazole), Dryan performed better than Tachimasari and Waseyutaka. For Dryan, total N was reduced by 84.0%, total P by 90.4%, COD by 83.4% and sulfonamide antimicrobials by 91.8-99.5%. Similar results were observed for Tachimasari and Waseyutaka. The results indicated that the treatment of swine wastewater using the constructed macrophyte floating bed system was effective in the removal of nutrients and veterinary antibiotics.

  7. Fluidized sand biofilters used to remove ammonia, biochemical oxygen demand, total coliform bacteria, and suspended solids from an intensive aquaculture effluent

    Science.gov (United States)

    Effluents from aquaculture facilities must be effectively managed to remove dissolved wastes and suspended solids that can pollute receiving bodies of water. High volume, dilute flows leaving settling or filtration units can appear pristine, but still contain dissolved wastes. Effective technologie...

  8. An obstacle to China's WWTPs: the COD and BOD standards for discharge into municipal sewers.

    Science.gov (United States)

    Liao, Zhenliang; Hu, Tiantian; Roker, Scott Albert C

    2015-11-01

    In 2001, a construction campaign regarding wastewater treatment plants (WWTPs) occurred in China. Unfortunately, the treatment has not yet achieved anticipated effectiveness. A critical reason for this is that the influent chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentrations in WWTPs are unacceptably low. This paper indicates that a fundamental, but commonly overlooked contributing factor to this problem is that a large portion of easily degradable COD and BOD is degraded prematurely before entering municipal sewers, and this is directly correlated to China's standards for pollutant discharging into municipal sewers. This perspective is further unfolded through retrospection of the history of Chinese wastewater treatment and the investigation of standards among developed zones and districts. This paper suggests that in China, the standards for pollutant discharging into municipal sewers should be relaxed. Meanwhile, unnecessary pretreatment of COD and BOD should cease for the purpose of ensuring that easily degradable COD and BOD can be transferred to WWTPs to improve treatment efficiency. Moreover, additional alternatives are presented to resolve this problem.

  9. Restricted fish feeding reduces cod otolith opacity

    DEFF Research Database (Denmark)

    Høie, H.; Folkvord, A.; Mosegaard, Henrik

    2008-01-01

    The purpose of this work was to examine the effect of reduced feeding and constant temperature on cod otolith opacity. Three groups of juvenile cod were given restricted food rations at different times for 4 months, resulting in depressed somatic growth. Otolith opacity was measured on pictures...... in otolith opacity were found between individual fish both within groups and between groups. In two of the three groups significantly more translucent otolith material was deposited in response to reduced feeding. Our results show that variations in feeding and hence fish growth resulted in variation...

  10. Enhanced biological phosphorus removal. Carbon sources, nitrate as electron acceptor, and characterization of the sludge community

    Energy Technology Data Exchange (ETDEWEB)

    Christensson, M.

    1997-10-01

    Enhanced biological phosphorus removal (EBPR) was studied in laboratory scale experiments as well as in a full scale EBPR process. The studies were focused on carbon source transformations, the use of nitrate as an electron acceptor and characterisation of the microflora. A continuous anaerobic/aerobic laboratory system was operated on synthetic wastewater with acetate as sole carbon source. An efficient EBPR was obtained and mass balances over the anaerobic reactor showed a production of 1.45 g poly-{beta}-hydroxyalcanoic acids (PHA), measured as chemical oxygen demand (COD), per g of acetic acid (as COD) taken up. Furthermore, phosphate was released in the anaerobic reactor in a ratio of 0.33 g phosphorus (P) per g PHA (COD) formed and 0.64 g of glycogen (COD) was consumed per g of acetic acid (COD) taken up. Microscopic investigations revealed a high amount of polyphosphate accumulating organisms (PAO) in the sludge. Isolation and characterisation of bacteria indicated Acinetobacter spp. to be abundant in the sludge, while sequencing of clones obtained in a 16S rDNA clone library showed a large part of the bacteria to be related to the high mole % G+C Gram-positive bacteria and only a minor fraction to be related to the gamma-subclass of proteobacteria to which Acinetobacter belongs. Operation of a similar anaerobic/aerobic laboratory system with ethanol as sole carbon source showed that a high EBPR can be achieved with this compound as carbon source. However, a prolonged detention time in the anaerobic reactor was required. PHA were produced in the anaerobic reactor in an amount of 1.24 g COD per g of soluble DOC taken up, phosphate was released in an amount of 0.4-0.6 g P per g PHA (COD) produced and 0.46 g glycogen (COD) was consumed per g of soluble COD taken up. Studies of the EBPR in the UCT process at the sewage treatment plant in Helsingborg, Sweden, showed the amount of volatile fatty acids (VFA) available to the PAO in the anaerobic stage to be

  11. Chemically enhanced primary treatment (CEPT) for removal of carbon and nutrients from municipal wastewater treatment plants: a case study of Shanghai.

    Science.gov (United States)

    Wang, Hongtao; Li, Fengting; Keller, Arturo A; Xu, Ran

    2009-01-01

    With Chemically Enhanced Primary Treatment (CEPT) as the short-term process, the capacity of Bailonggang Wastewater Treatment Plant accounts for almost 25% of the total capacity of wastewater treatment in Shanghai, China. However, shortly after this plant was placed in operation in 2004, it was found that the effluent of CEPT couldn't meet the new national discharge criteria. Although the removal of phosphate is almost 80%, chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) in the effluent is frequently found to exceed the standards. The primary goal of this research is to investigate the possibility of optimizing the CEPT to make it meet the discharge criteria before it is upgraded to a secondary treatment. An oxidant is adopted to remove NH3-N, and a high performance polyaluminum chloride (HP-PACl) is synthesized to enhance the removal of COD. It is found that HP-PACl improves the removal of COD, and the oxidant enhances NH3-N removal effectively. However, to meet the requirement of a newly implemented stricter discharge standard, it is necessary to upgrade this CEPT to a secondary treatment. The results of this study provide scientific evidence for the upgrade of the Bailonggang Wastewater Treatment Plant.

  12. Pilot-scale experience with biological nutrient removal and biomass yield reduction in a liquid-solid circulating fluidized bed bioreactor.

    Science.gov (United States)

    Chowdhury, Nabin; Nakhla, George; Zhu, Jesse; Islam, Mohammad

    2010-01-01

    A pilot-scale liquid-solid circulating fluidized bed (LSCFB) bioreactor was developed at the Adelaide Pollution Control Plant, London, Ontario, Canada, to study its commercial viability for biological nutrient removal. Lava rock particles of 600 microm were used as a biomass carrier media. The LSCFB removed approximately 90% organic, 80% nitrogen, and 70% phosphorus at loading rates of 4.12 kg COD/m3 x d, 0.26 kg N/m3 x d, and 0.052 kg P/m3 x d, and an empty bed contact time of 1.5 hours. Effluent characterized by < 1.0 mg NH4-N/L, < 5.0 mg NO3-N/ L, < 1.0 mg PO4-P/L, < 10 mg TN/L, < 10 mg SBOD/L, and 10 to 15 mg volatile suspended solids (VSS)/L can easily meet the criteria for nonpotable reuse of treated wastewater. The system removed nutrients without using any chemicals, and the secondary clarifier removed suspended solids removal without chemicals. A significant reduction (approximately 75%) in biomass yield to 0.12 to 0.16 g VSS/g chemical oxygen demand (COD) was observed, primarily because of long biological solids retention time (SRT) of 20 to 39 days and a combination of anoxic and aerobic COD consumption.

  13. Anammox for ammonia removal from pig manure effluents: Effect of organic matter content on process performance

    DEFF Research Database (Denmark)

    Salces, Beatriz Molinuevo; García, M. C.; Karakashev, Dimitar Borisov

    2009-01-01

    oxidation) diluted with synthetic wastewater. High ammonium removal was achieved, up to 92.1 +/- 4.9% for diluted UASB-post-digested effluent (95 mg COD L-1) and up to 98.5 +/- 0.8% for diluted partially oxidized effluent (121 mg COD L-1). Mass balance clearly showed that an increase in organic loading...... improved ammonium removal at high organic matter concentration. Up to threshold organic load concentration of 142 mg COD L-1 of UASB-post-digested effluent and 242 mg COD L-1 of partially oxidized effluent, no effect of organic loading on ammonia removal was registered (ammonium removal was above 80...

  14. Load maximization of a liquid-solid circulating fluidized bed bioreactor for nitrogen removal from synthetic municipal wastewater.

    Science.gov (United States)

    Chowdhury, Nabin; Nakhla, George; Zhu, Jesse

    2008-03-01

    A novel liquid-solid circulating fluidized bed bioreactor (LSCFB) configured with anoxic and aerobic columns and lava rock as the biofilm carrier was used to treat synthetic municipal wastewater. Four different empty bed contact times (EBCTs) of 0.82, 0.65, 0.55, and 0.44 h were examined to optimize nutrient removal capability of the system. The LSCFB demonstrated tertiary effluent quality organic and nitrogen removal efficiencies. Effluent characteristics of the LSCFB were soluble biological oxygen demand (SBOD)10 mg l(-1) and total nitrogen (TN)<10 mg l(-1) at organic loading rate (OLR) of 5.3 kg m(-3)d(-1) and nitrogen loading rate of 0.54 kg Nm(-3)d(-1). Remarkably low yields of 0.14, 0.17, 0.19, and 0.21 g VSS g(-1)COD were observed at OLR of 2.6, 3.2, 4.1 and 5.3 kg COD m(-3)d(-1), where increment of biomass growth and detachment rate were also experienced with increasing OLR. However the system demonstrated only 30% phosphorus removal, and mass balances along the anoxic and aerobic columns showed biological phosphorus removal in the system. Organic mass balance showed that approximately 40% of the influent COD was utilized in the anoxic column and the remaining COD was oxidized in the aerobic column. The system is very efficient in nitrification-denitrification, with more than 90% nitrification of ammonium and overall nitrogen removal in the LSCFB was 70+/-11% even at an EBCT of 0.44 h.

  15. Correlation between Biochemical Oxygen Demand and Chemical Oxygen Demand for Various Wastewater Treatment Plants in Egypt to Obtain the Biodegradability Indices

    OpenAIRE

    Khaled Zaher Abdallah; Gina Hammam

    2014-01-01

    Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) are the most commonly used parameters for the characterization of wastewaters. Both of these parameters have advantages and disadvantages, and the choice usually depends on many factors such as the time period required to determine each one of them. It is essential to obtain a correlation between BOD5 and COD for various wastewater treatment plants, to help in the design and operation of these plants. In this paper, the biodegr...

  16. Sediments of Cape Cod Bay, Massachusetts (HOUGH42 shapefile)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Cape Cod Bay, lying on the Massachusetts coast partly enclosed by Cape Cod, is in a glaciated region of low relief. Coarse sediments generally occur in areas exposed...

  17. Removal of oxytetracycline (OTC) in a synthetic pharmaceutical wastewater by a sequential anaerobic multichamber bed reactor (AMCBR)/completely stirred tank reactor (CSTR) system: biodegradation and inhibition kinetics.

    Science.gov (United States)

    Sponza, Delia Teresa; Çelebi, Hakan

    2012-01-01

    An anaerobic multichamber bed reactor (AMCBR) was effective in removing both molasses-chemical oxygen demand (COD), and the antibiotic oxytetracycline (OTC). The maximum COD and OTC removals were 99% in sequential AMCBR/completely stirred tank reactor (CSTR) at an OTC concentration of 300 mg L(-1). 51%, 29% and 9% of the total volatile fatty acid (TVFA) was composed of acetic, propionic acid and butyric acids, respectively. The OTC loading rates at between 22.22 and 133.33 g OTC m(-3) d(-1) improved the hydrolysis of molasses-COD (k), the maximum specific utilization of molasses-COD (k(mh)) and the maximum specific utilization rate of TVFA (k(TVFA)). The direct effect of high OTC loadings (155.56 and -177.78 g OTC m(-3) d(-1)) on acidogens and methanogens were evaluated with Haldane inhibition kinetic. A significant decrease of the Haldane inhibition constant was indicative of increases in toxicity at increasing loading rates.

  18. Removal of residual dissolved methane gas in an upflow anaerobic sludge blanket reactor treating low-strength wastewater at low temperature with degassing membrane.

    Science.gov (United States)

    Bandara, Wasala M K R T W; Satoh, Hisashi; Sasakawa, Manabu; Nakahara, Yoshihito; Takahashi, Masahiro; Okabe, Satoshi

    2011-05-01

    In this study, we investigated the efficiency of dissolved methane (D-CH(4)) collection by degasification from the effluent of a bench-scale upflow anaerobic sludge blanket (UASB) reactor treating synthetic wastewater. A hollow-fiber degassing membrane module was used for degasification. This module was connected to the liquid outlet of the UASB reactor. After chemical oxygen demand (COD) removal efficiency of the UASB reactor became stable, D-CH(4) discharged from the UASB reactor was collected. Under 35 °C and a hydraulic retention time (HRT) of 10 h, average D-CH(4) concentration could be reduced from 63 mg COD L(-1) to 15 mg COD L(-1); this, in turn, resulted in an increase in total methane (CH(4)) recovery efficiency from 89% to 97%. Furthermore, we investigated the effects of temperature and HRT of the UASB reactor on degasification efficiency. Average D-CH(4) concentration was as high as 104 mg COD L(-1) at 15 °C because of the higher solubility of CH(4) gas in liquid; the average D-CH(4) concentration was reduced to 14 mg COD L(-1) by degasification. Accordingly, total CH(4) recovery efficiency increased from 71% to 97% at 15 °C as a result of degasification. Moreover, degasification tended to cause an increase in particulate COD removal efficiency. The UASB reactor was operated at the same COD loading rate, but different wastewater feed rates and HRTs. Although average D-CH(4) concentration in the UASB reactor was almost unchanged (ca. 70 mg COD L(-1)) regardless of the HRT value, the CH(4) discharge rate from the UASB reactor increased because of an increase in the wastewater feed rate. Because the D-CH(4) concentration could be reduced down to 12 ± 1 mg COD L(-1) by degasification at an HRT of 6.7 h, the CH(4) recovery rate was 1.5 times higher under degasification than under normal operation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Multi-chamber microbial desalination cell for improved organic matter and dissolved solids removal from wastewater.

    Science.gov (United States)

    Pradhan, Harapriya; Ghangrekar, M M

    2014-01-01

    A five-chamber microbial desalination cell (MDC) with anode, cathode, one central desalination chamber and two concentrate chambers separated by ion exchange membranes was operated in batch mode for more than 60 days. The performance of the MDC was evaluated for chemical oxygen demand (COD) removal, total dissolved solids (TDS) removal and energy production. An average COD removal of 81 ± 2.1% was obtained using acetate-fed wastewater as substrate in the anodic chamber inoculated with mixed anaerobic sludge. TDS removals of 58, 70 and 78% were observed with salt concentration of 8, 20 and 30 g/L, respectively, in the middle desalination chamber. The MDC produced a maximum power output of 16.87 mW/m(2) during polarization. The highest Coulombic efficiency of 12 ± 2.4% was observed in this system using mixed anaerobic sludge as inoculum. The system effectively demonstrated capability for simultaneous organic matter removal and desalination along with power generation.

  20. Removal of stigmasterol from Kraft mill effluent by aerobic biological treatment with steroidal metabolite detection.

    Science.gov (United States)

    Chamorro, Soledad; Vergara, Juan P; Jarpa, Mayra; Hernandez, Victor; Becerra, Jose; Vidal, Gladys

    2016-10-14

    Stigmasterol is a phytosterol contained in Kraft mill effluent that is able to increase over 100% after aerobic biological treatment. This compound can act as an endocrine disrupter as its structure is similar to that of cholesterol. The aim of this study was to evaluate the removal of stigmasterol from Kraft mill effluents treated by a moving bed biofilm reactor (MBBR) with steroidal metabolite detection. The MBBR was operated for 145 days, with a hydraulic retention time of 2 days. Stigmasterol and steroidal metabolites were detected by gas chromatography with a flame ionization detector during MBBR operation. The results show that the MBBR removed 87.4% of biological oxygen demand (BOD5), 61.5% of chemical oxygen demand (COD), 24.5% of phenol and 31.5% of lignin, expressed in average values. The MBBR system successfully removed 100% of the stigmasterol contained in the influent (33 µg L(-1)) after 5 weeks of operation. In that case, the organic load rate was 0.343 kg COD m(-3) d(-1). Furthermore, different steroidal compounds (e.g., testosterone propionate, stigmast-4-en-3-one, 5α-pregnan-12-one-20α-hydroxy, 5α-pregnane-3,11,20-trione and 3α-hydroxy-5α-androstane-11,17-dione were detected in the Kraft mill effluent as potential products of phytosterol biotransformation.

  1. Modeling and Optimization of New Flocculant Dosage and pH for Flocculation: Removal of Pollutants from Wastewater

    Directory of Open Access Journals (Sweden)

    Ammar Salman Dawood

    2013-03-01

    Full Text Available In this paper, a new ferric chloride-(polyvinylpyrrolidone-grafted-polyacrylamide hybrid copolymer was successfully synthesized by free radical polymerization in solution using ceric ammonium nitrate as redox initiator. The hybrid copolymer was characterized by Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. Response surface methodology (RSM, involving central composite design (CCD matrix with two of the most important operating variables in the flocculation process; hybrid copolymer dosage and pH were utilized for the study and for the optimization of the wastewater treatment process. Response surface analyses showed that the experimental data could be adequately fitted to quadratic polynomial models. Under the optimum conditions, the turbidity and chemical oxygen demand (COD removal efficiencies were 96.4% and 83.5% according to RSM optimization, whereas the optimum removals based on the genetic algorithm (GA were 96.56% and 83.54% for the turbidity and COD removal models. Based on these results, wastewater treatment using this novel hybrid copolymer has proved to be an effective alternative in the overseeing of turbidity and COD problems of municipal wastewater.

  2. 78 FR 32612 - Collect on Delivery (COD)-Service Features

    Science.gov (United States)

    2013-05-31

    ... 111 Collect on Delivery (COD)--Service Features AGENCY: Postal Service\\TM\\. ACTION: Proposed rule... * * * * * 503 Extra Services * * * * * 13.0 Collect on Delivery (COD) * * * * * 13.2 Basic Information 13.2.1... collect on delivery (COD) service to mail an article for which the mailer has not been paid and have...

  3. Demand Uncertainty

    DEFF Research Database (Denmark)

    Nguyen, Daniel Xuyen

    This paper presents a model of trade that explains why firms wait to export and why many exporters fail. Firms face uncertain demands that are only realized after the firm enters the destination. The model retools the timing of uncertainty resolution found in productivity heterogeneity models...... in untested destinations. The option to forecast demands causes firms to delay exporting in order to gather more information about foreign demand. Third, since uncertainty is resolved after entry, many firms enter a destination and then exit after learning that they cannot profit. This prediction reconciles...

  4. A portable photoelectrochemical probe for rapid determination of chemical oxygen demand in wastewaters.

    Science.gov (United States)

    Zhang, Shanqing; Li, Lihong; Zhao, Huijun

    2009-10-15

    A photoelectrochemical probe for rapid determination of chemical oxygen demand (COD) is developed using a nanostructured mixed-phase TiO2 photoanode, namely PeCOD probe. A UV-LED light source and a USB mircroelectrochemical station are powered and controlled by a laptop computer, which makes the probe portable for onsite COD analyses. The photoelectrochemical measurement of COD was optimized in terms of light intensity, applied bias, and pH. Under the optimized conditions, the net steady state currents originated from the oxidation of organic compounds were found to be directly proportional to COD concentrations. A practical detection limit of 0.2 ppm COD and a linear range of 0-120 ppm COD were achieved. The analytical method using the portable PeCOD probe has the advantages of being rapid, low cost, robust, user-friendly, and environmental friendly. It has been successfully applied to determine the COD values of the synthetic samples consisting of potassium hydrogen phthalate, D-glucose, glutamic acid, glutaric acid, succinic acid, and malonic acid, and real samples from various industries, such as bakery, oil and grease manufacturer, poultry, hotel, fine food factory, and fresh food producer, commercial bread manufacturer. Excellent agreement between the proposed method and the conventional COD method (dichromate) was achieved.

  5. Evaluation of Organic Matter Removal Efficiency and Microbial Enzyme Activity in Vertical-Flow Constructed Wetland Systems

    Directory of Open Access Journals (Sweden)

    Qiaoling Xu

    2016-09-01

    Full Text Available In this study, enzyme activities and their relationships to organics purification were investigated in three different vertical flow constructed wetlands, namely system A (planting Pennisetum sinese Roxb, system B (planting Pennisetum purpureum Schum., and system C (no plant. These three wetland systems were fed with simulation domestic sewage at an influent flow rate of 20 cm/day. The results showed that the final removal efficiency of Chemical Oxygen Demand (COD in these three systems was 87%, 85% and 63%, respectively. Planting Pennisetum sinese Roxb and Pennisetum purpureum Schum. could improve the amount of adsorption and interception for organic matter in the substrate, and the amount of interception of organic matter in planting the Pennisetum sinese Roxb system was higher than that in planting the Pennisetum purpureum Schum. system. The activities of enzymes (urease, phosphatase and cellulase in systems A and B were higher than those in system C, and these enzyme activities in the top layer (0–30 cm were significantly higher than in the other layers. The correlations between the activities of urease, phosphatase, cellulase and the COD removal rates were R = 0.815, 0.961 and 0.973, respectively. It suggests that using Pennisetum sinese Roxb and Pennisetum purpureum Schum. as wetland plants could promote organics removal, and the activities of urease, phosphatase and cellulase in those three systems were important indicators for COD purification from wastewater. In addition, 0–30 cm was the main function layer. This study could provide a theoretical basis for COD removal in the wetland system and supply new plant materials for selection.

  6. Demand forecasting

    OpenAIRE

    Gregor, Belčec

    2011-01-01

    Companies operate in an increasingly challenging environment that requires them to continuously improve all areas of the business process. Demand forecasting is one area in manufacturing companies where we can hope to gain great advantages. Improvements in forecasting can result in cost savings throughout the supply chain, improve the reliability of information and the quality of the service for our customers. In the company Danfoss Trata, d. o. o. we did not have a system for demand forecast...

  7. Selective haddock (Melanogrammus aeglefinus) trawling: Avoiding cod (Gadus morhua) bycatch

    DEFF Research Database (Denmark)

    Krag, Ludvig Ahm; Holst, René; Madsen, Niels;

    2010-01-01

    The critical condition of the North Sea cod stocks has resulted in restrictions on not only cod, but also haddock and other species that are caught together with cod. Thus full exploitation of the haddock stock is unachievable unless cod can be excluded from the haddock catch. We designed a selec...... dependent: smaller cod escaped the trawl in greater numbers than did larger individuals. Whiting, saithe. lemon sole, and plaice were included in the analysis. (C) 2009 Elsevier B.V. All rights reserved....

  8. Removal performance and water quality analysis of paper machine white water in a full-scale wastewater treatment plant.

    Science.gov (United States)

    Shi, Shuai; Wang, Can; Fang, Shuai; Jia, Minghao; Li, Xiaoguang

    2016-09-29

    Paper machine white water is generally characterized as a high concentration of suspended solids and organic matters. A combined physicochemical-biological and filtration process was used in the study for removing pollutants in the wastewater. The removal efficiency of the pollutant in physicochemical and biological process was evaluated, respectively. Furthermore, advanced technology was used to analyse the water quality before and after the process treatment. Experimental results showed that the removal efficiency of suspend solids (SS) of the system was above 99%, while the physicochemical treatment in the forepart of the system had achieved about 97%. The removal efficiency of chemical oxygen demand (COD) and colour had the similar trend after physicochemical treatment and were corresponding to the proportion of suspended and the near-colloidal organic matter in the wastewater. After biological treatment, the removal efficiency of COD and colour achieved were about 97% and 90%, respectively. Furthermore, molecular weight (MW) distribution analysis showed that after treatment low MW molecules (chromatography/mass spectrometry showed that the composition of organic matter in the wastewater was not complicated. Methylsiloxanes were the typical organic components in the raw wastewater and most of them were removed after treatment.

  9. Improvement of an integrated system of membrane bioreactor and worm reactor by phosphorus removal using additional post-chemical treatment.

    Science.gov (United States)

    Liu, Jia; Zuo, Wei; Tian, Yu; Zhang, Jun; Li, Hui; Li, Lipin

    2016-11-01

    A membrane bioreactor (MBR) coupled with a worm reactor (SSBWR) was designed as SSBWR-MBR for sewage treatment and excess sludge reduction. However, total phosphorus (TP) release caused by worm predation in the SSBWR could increase the effluent TP concentration in the SSBWR-MBR. To decrease the amount of TP excreted, chemical treatment reactor was connected after the SSBWR-MBR to remove the excess phosphorus (P). The effects of chemical treatment at different time intervals on the performance of the SSBWR-MBR were assessed. The results showed that a maximum TP removal efficiency of 21.5 ± 1.0% was achieved in the SSBWR-MBR after chemical treatment. More importantly, a higher sulfate concentration induced by chemical treatment could promote TP release in the SSBWR, which provided further TP removal from the SSBWR-MBR. Additionally, chemical oxygen demand (COD) removal efficiency of the SSBWR-MBR was increased by 1.3% after effective chemical treatment. In the SSBWR-MBR, the chemical treatment had little effects on NH3-N removal and sludge production. Eventually, chemical treatment also alleviated the membrane fouling in the SSBWR-MBR. In this work, the improvement on TP, COD removal and membrane fouling alleviation was achieved in the SSBWR-MBR using additional chemical treatment.

  10. Cycles and trends in cod populations.

    Science.gov (United States)

    Bjørnstad, O N; Fromentin, J M; Stenseth, N C; Gjøsaeter, J

    1999-04-27

    Year-to-year fluctuations in fish stocks are usually attributed to variability in recruitment, competition, predation, and changes in catchability. Trends in abundance, in contrast, are usually ascribed to human exploitation and large-scale environmental changes. In this study, we demonstrate, through statistical modeling of survey data (1921-1994) of cod from the Norwegian Skagerrak coast, that both short- and long-term variability may arise from the same set of age-structured interactions. Asymmetric competition and cannibalism between cohorts generate alternating years of high and low abundance. Intercohort interactions also resonate the recruitment variability so that long-term trends are induced. The coupling of age-structure and variable recruitment should, therefore, be considered when explaining both the short- and long-term fluctuations displayed by the coastal cod populations. Resonant effects may occur in many marine populations that exhibit this combination of traits.

  11. Oxidation Process of H 2 O /UV for COD Reduction of Wastewater from Soybean Tofu Production

    Directory of Open Access Journals (Sweden)

    Komala Pontas

    2015-12-01

    Full Text Available Chemical Oxygen Demand (COD reduction of wastewater from soybean tofu production was studied by conducting advanced oxidation process (AOP using hydrogen peroxide with UV radiation catalysts in a closed cylindrical glass reactor. The hydroxyl radical (*OH concentration from H2O decomposition was modeled, and exponential trends were found for the *OH concentration over radiation time and operation temperature. As a result, it was found that the maximal *OH concentration was 0.209 mol L-12 at 240 minutes and 50 °C. The *OH concentration exponentially increased following rise in operation temperature. The H2O /UV AOP application reduced COD concentration to approximately 42.41% from 10,545 to 6,073.2 mol L-12 at 240 minutes and 50 °C. In addition, the pseudo second order kinetics is a reliable model to present the COD reduction kinetics with the correlation coefficient R in the range of 95.9 to 99.4%. The kinetics constant increased with rise in operation temperature, and it was approximately 2.30E-07, 2.590E-07, and 3.03E-07 L mg-1 min-1 for 30, 40, and 50 °C, respectively. The activation energy of COD reduction obtained was approximately 0.0138 J mol-1.

  12. Removal of the 2-Mercaptobenotiazole from Model Wastewater by Ozonation

    Directory of Open Access Journals (Sweden)

    Jan Derco

    2014-01-01

    Full Text Available The feasibility of ozonation process for 2-mercaptobenzothiazole (2-MBT removal follows from results of ozonation of the model wastewater. Total removal of 2-MBT was observed after 20 minutes of ozonation. Very good reproducibility of repeated ozonation trials including sampling and analysis was observed. However, the majority of dissolved organic carbon (DOC and chemical oxygen demand (COD remained in the reaction mixture. Benzothiazole (BT and 2-hydroxybenzothiazole (OBT intermediates were identified during degradation of 2-MBT with ozone. In addition to the above benzothiazole derivatives, the creation of some other organic compounds follows from results of mass balance. The best fits of experimental data were obtained using the first kinetic model for 2-MBT and zero-order kinetic model for COD and DOC. The reaction time of 60 minutes can be considered as effective with regard to controlled oxidation in order to increase a portion of partially oxidized substances. Higher biodegradability and lower toxicity of ozonation products on respiration activity of activated sludge microorganisms was observed at higher ozonation time.

  13. Nutrient removal and biogas upgrading by integrating freshwater algae cultivation with piggery anaerobic digestate liquid treatment.

    Science.gov (United States)

    Xu, Jie; Zhao, Yongjun; Zhao, Guohua; Zhang, Hui

    2015-08-01

    An integrated approach that combined freshwater microalgae Scenedesmus obliquus (FACHB-31) cultivation with piggery anaerobic digestate liquid treatment was investigated in this study. The characteristics of algal growth, biogas production, and nutrient removal were examined using photobioreactor bags (PBRbs) to cultivate S. obliquus (FACHB-31) in digestate with various digestate dilutions (the concentration levels of 3200, 2200, 1600, 1200, 800, and 400 mg L(-1) chemical oxygen demand (COD)) during 7-day period. The effects of the level of pollutants on nutrient removal efficiency and CO2 removal process were investigated to select the optimum system for effectively upgrade biogas and simultaneously reduce the nutrient content in digestate. The treatment performance displayed that average removal rates of COD, total nitrogen (TN), total phosphorous (TP), and CO2 were 61.58-75.29, 58.39-74.63, 70.09-88.79, and 54.26-73.81 %, respectively. All the strains grew well under any the dilution treatments. With increased initial nutrient concentration to a certain range, the CO4 content (v/v) of raw biogas increased. Differences in the biogas enrichment of S. obliquus (FACHB-31) in all treatments mainly resulted from variations in biomass productivity and CO2 uptake. Notably, the diluted digestate sample of 1600 mg L(-1) COD provided an optimal nutrient concentration for S. obliquus (FACHB-31) cultivation, where the advantageous nutrient and CO2 removals, as well as the highest productivities of biomass and biogas upgrading, were revealed. Results showed that microalgal biomass production offered real opportunities to address issues such as CO2 sequestration, wastewater treatment, and biogas production.

  14. Removal of anaerobic soluble microbial products in a biological activated carbon reactor

    Institute of Scientific and Technical Information of China (English)

    Xiaojing Dong; Weili Zhou; Shengbing He

    2013-01-01

    The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable.Focusing on the biodegradation of anaerobic SMP,the biological activated carbon (BAC) was introduced into the anaerobic system.The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors.The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2,i.e.,BAC) functioned as a polishing step to remove SMP produced in UASB1.The results showed that 90% of the SMP could be removed before granular activated carbon was saturated.After the saturation,the SMP removal decreased to 60% on the average.Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation.A strain of SMP-degrading bacteria,which was found highly similar to Klebsiella sp.,was isolated,enriched and inoculated back to the BAC reactor.When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m3·day),the effluent from the BAC reactor could meet the discharge standard without further treatment.Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective,cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L.

  15. Performance and Metabolic Demand of a New Repeated-Sprint Ability Test in Basketball Players: Does the Number of Changes of Direction Matter?

    Science.gov (United States)

    Zagatto, Alessandro M; Ardigò, Luca P; Barbieri, Fabio A; Milioni, Fabio; Dello Iacono, Antonio; Camargo, Bruno H F; Padulo, Johnny

    2017-09-01

    Zagatto, AM, Ardigò, LP, Barbieri, FA, Milioni, F, Dello Iacono, A, Camargo, BHF, and Padulo, J. Performance and metabolic demand of a new repeated-sprint ability test in basketball players: does the number of changes of direction matter? J Strength Cond Res 31(9): 2438-2446, 2017-This study compared 2 repeated-sprint ability (RSA) tests in basketball players. Both tests included 10 × 30-m sprints, with the difference that the previously validated test (RSA2COD) featured 2 changes of direction (COD) per sprint, whereas the experimental test (RSA5COD) featured 5 CODs per sprint. Test performances and metabolic demands were specifically assessed in 20 basketball players. First, RSA5COD test-retest reliability was investigated. Then, RSA2COD, RSA5COD sprint times, peak speeds, oxygen uptake (V[Combining Dot Above]O2) and posttest blood lactate concentration [La] were measured. The RSA5COD results showed to be reliable. RSA2COD performance resulted better than the RSA5COD version (p sprint times and higher peak speeds. Over sprints, the tests did not differ from each other in terms of V[Combining Dot Above]O2 (p > 0.05). Over whole bout, the RSA2COD was more demanding than the RSA5COD, considering overall metabolic power requirement (i.e., VO2-driven + [La]-driven components). Given that RSA5COD (a) mimics real game-play as sprint distance and action change frequency/direction and (b) has the same metabolic expenditure per task completion as metabolic cost, RSA5COD is a valuable option for players and coaches for training basketball-specific agility and assessing bioenergetic demands.

  16. Effectiveness of fluidized pellet bed for removing soluble contaminants

    Institute of Scientific and Technical Information of China (English)

    WANG Xiaochang; LI Zhihua; WANG Zhen; LI Jinrong; LI Jiayu; CHEN Rong

    2009-01-01

    Fluidized pellet bed (FPB) has been successfully applied in water and wastewater treatment. However, the removal mechanism of contaminants especially the soluble ones, is still unclear. This study aimed to evaluate the effectiveness of FPB reactor for removing soluble contaminants from synthetic wastewater. By only coagulation through jar test operation with addition of polyaluminium chloride (PACl) as primary coagulant and polyacryamide (PAM) as coagulant-aid, the removals of soluble chemical oxygen demand (COD), suspended solids (SS), total phosphorus (TP), and NH4+-N were found to be only 2.2%--7.5%, 5.7%--25.5%, and 9.9%--18.5%, respectively. However, by FPB operation under the same dosage of coagulants, these values increased to 82.7%, 37.2%, and 50%, indicating that the formation of pellets in the FPB effectively enhanced the removal of soluble contaminants. By careful comparison of the settleablility and filterability of the pollutants after coagulation, the originally soluble contaminants could be divided into three groups, namely: (i) coagulated-and-settleable, (ii) coagulated-but-nonsettleable, and (iii) uncoagulable. It was found that not only the first two groups but also a large part of the third group could be effectively removed by FPB operation. However, the mechanism for the removal of the uncoagulable pollutants by FPB operation still needs further investigation.

  17. Photoelectrocatalytic degradation of high COD dipterex pesticide by using TiO2/Ni photo electrode

    Institute of Scientific and Technical Information of China (English)

    Tao Fang; Chao Yang; Lixia Liao

    2012-01-01

    A TiO2 thin film electrode deposited on porous nickel net (TiO2/Ni) was prepared by the sol-gel method,and the surface morphology,crystal structure features and the grain size were characterized by Field emission scan electron microscopy (FESEM) and X-ray diffraction (XRD).The photoelectrocatalytic system was set up using a UV high-pressure mercury lamp as the light source,TiO2 coated on foamed nickel as photo anode,Pt sheet as counter electrode and the pesticide dipterex in synthetic wastewater.Various factors that influence the photoelectrocatalytic decomposition of dipterex pesticide have been studied,such as degradation time,the type of electrolyte,current density,original pH value and different degradation methods.The prepared catalysts were employed to photoelectrocatalytically degrade the pesticide dipterex under UV irradiation,comparing the results with photocatalytic degradation and electrochemical oxidation.The results indicated that under the optimal conditions of 0.02 mol/L NaCl as the supporting electrolyte,current density =2.5 mA/cm2,pH 6.0 and dipterex pesticide 40 mg/L,and reaction time 2 hr,dipterex chemical oxygen demand (COD) removal rate and organophosphorous conversion of up to 82.6% and 83.5% were achieved,respectively.The method of photoelectrocatalytie degradation is more efficient than photocatalysis and electrochemical oxidation.The possible roles of the electrolytes on the reactions and probable mechanisms were also discussed.

  18. Bioelectricity generation and microcystins removal in a blue-green algae powered microbial fuel cell.

    Science.gov (United States)

    Yuan, Yong; Chen, Qing; Zhou, Shungui; Zhuang, Li; Hu, Pei

    2011-03-15

    Bioelectricity production from blue-green algae was examined in a single chamber tubular microbial fuel cell (MFC). The blue-green algae powered MFC produced a maximum power density of 11 4 mW/m(2) at a current density of 0.55 mA/m(2). Coupled with the bioenergy generation, high removal efficiencies of chemical oxygen demand (COD) and nitrogen were also achieved in MFCs. Over 78.9% of total chemical oxygen demand (TCOD), 80.0% of soluble chemical oxygen demand (SCOD), 91.0% of total nitrogen (total-N) and 96.8% ammonium-nitrogen (NH(3)-N) were removed under closed circuit conditions in 12 days, which were much more effective than those under open circuit and anaerobic reactor conditions. Most importantly, the MFC showed great ability to remove microcystins released from blue-green algae. Over 90.7% of MC-RR and 91.1% of MC-LR were removed under closed circuit conditions (500Ω). This study showed that the MFC could provide a potential means for electricity production from blue-green algae coupling algae toxins removal.

  19. Removal of triphenylmethane dyes by bacterial consortium.

    Science.gov (United States)

    Cheriaa, Jihane; Khaireddine, Monia; Rouabhia, Mahmoud; Bakhrouf, Amina

    2012-01-01

    A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila)-(CM-4) was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable color-removal capability against crystal violet (50 mg/L) and malachite green (50 mg/L) dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD) removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes.

  20. Removal of Triphenylmethane Dyes by Bacterial Consortium

    Directory of Open Access Journals (Sweden)

    Jihane Cheriaa

    2012-01-01

    Full Text Available A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila-(CM-4 was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable color-removal capability against crystal violet (50 mg/L and malachite green (50 mg/L dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes.

  1. Anaerobic treatment of cellulose bleach plant wastewater: chlorinated organics and genotoxicity removal

    Directory of Open Access Journals (Sweden)

    T. R. Chaparro

    2011-12-01

    Full Text Available This study assessed the removal efficiency of organic matter and how it relates to the decrease of toxic and mutagenic effects when an anaerobic reactor is used to treat the bleaching effluent from two kraft pulp mills. Parameters such as COD (chemical oxygen demand, DOC (dissolved organic carbon, AOX (adsorbable organic halogen, ASL (acid soluble lignin, color, chlorides, total phenols and absorbance values in the UV-VIS spectral region were measured. The acute and chronic toxicity and genetic toxicity assessments were performed with Daphnia similis, Ceriodaphnia sp. and Allium cepa L, respectively. The removal efficiency of organic matter measured as COD, ranged from 45% to 55%, while AOX removal ranged from 40% to 45%. The acute toxic and chronic effects, as well as the cytotoxic, genotoxic and mutagenic effects, decrease as the biodegradable fraction of the organics is removed. These results, together with the organic load measurement of the effluents of the anaerobic treatment, indicate that these effluents are recalcitrant but not toxic. As expected, color increased when the anaerobic treatment was applied. However, the colored compounds are of microbial origin and do not cause an increase in genotoxic effects. To discharge the wastewater, it is necessary to apply a physico-chemical or aerobic biological post-treatment to the effluents of the anaerobic reactor.

  2. Sulfamethoxazole and ciprofloxacin removal using a horizontal-flow anaerobic immobilized biomass reactor.

    Science.gov (United States)

    Chatila, Sami; Amparo, Maura R; Carvalho, Lucas S; Penteado, Eduardo D; Tomita, Inês N; Santos-Neto, Álvaro J; Lima Gomes, Paulo C F; Zaiat, Marcelo

    2016-01-01

    The antibiotics sulfamethoxazole (SMTX) and ciprofloxacin (CIP) are commonly used in human and veterinary medicine, which explains their occurrence in wastewater. Anaerobic reactors are low-cost, simple and suitable technology to wastewater treatment, but there is a lack of studies related to the removal efficiency of antibiotics. To overcome this knowledge gap, the objective of this study was to evaluate the removal kinetics of SMTX and CIP using a horizontal-flow anaerobic immobilized biomass reactor. Two different concentrations were evaluated, for SMTX 20 and 40 μg L(-1); for CIP 2.0 and 5.0 μg L(-1). The affluent and effluent analysis was carried out in liquid chromatography/tandem mass spectrometry (LC-MS/MS) with the sample preparation procedure using an off-line solid-phase extraction. This method was developed, validated and successfully applied for monitoring the affluent and effluent samples. The removal efficiency found for both antibiotics at the two concentrations studied was 97%. Chemical oxygen demand (COD) exhibited kinetic constants that were different from that observed for the antibiotics, indicating the absence of co-metabolism. Also, though the antibiotic concentration was increased, there was no inhibitory effect in the removal of COD and antibiotics.

  3. Optimization of simultaneous biomass production and nutrient removal by mixotrophic Chlorella sp. using response surface methodology.

    Science.gov (United States)

    Lee, Yu-Ru; Chen, Jen-Jeng

    2016-01-01

    The bioprospecting of potentially mixotrophic microalgae in a constructed wetland was conducted. A locally isolated microalga, Chlorella sp., was grown to determine the effect of temperature, aeration rate, and cultivation time on simultaneous biomass production and nutrient removal from piggery wastewater using central composite design (CCD). The most important variable for the biomass productivity of Chlorella sp. was aeration rate, while that for lipid content and nutrient removal efficiency was cultivation time. Total nitrogen (TN) and total phosphorus (TP) removal efficiencies were higher than that of chemical oxygen demand (COD) from piggery wastewater. The CCD results indicate that the highest biomass productivity (79.2 mg L(-1) d(-1)) and simultaneous nutrient removal efficiency (TN 80.9%, TP 99.2%, COD 74.5%) were obtained with a cultivation temperature of 25 °C, a cultivation time of 5 days, and an air aeration rate of 1.6 L L(-1) min(-1). Palmitic acid (C16:0) and linoleic acid (C18:2) were both abundant in Chlorella sp. cells under mixotrophic cultivation with piggery wastewater.

  4. Organochlorine pesticides removal from wastewater by pine bark adsorption after activated sludge treatment.

    Science.gov (United States)

    Sousa, Sérgio; Jiménez-Guerrero, Pedro; Ruiz, Antonio; Ratola, Nuno; Alves, Arminda

    2011-04-01

    Pesticides have been responsible for strong environmental impacts, mainly due to their persistence in the environment. Removal technologies are usually combined, because degradation of organic matter is needed prior to a tertiary treatment to guarantee pesticides elimination to levels below legal limits (normally 0.1 microg L(-1)). Pine bark was studied as an alternative to activated carbon, for organochlorine pesticides removal. A combination of technologies based on biodegradation with activated sludge followed by pine bark adsorption treatment was used for lindane (LIN) and heptachlor (HEP) removal from contaminated waters. Pesticides were quantified throughout the process by GC-ECD preceded by solid-phase microextraction (SPME). An experimental set-up was maintained for 4 months, by feeding a standard solution with pesticides concentration of 1 microg L(-1) each and known organic matter (Chemical Oxygen Demand, COD, -563 mg O2 L(-1)) on a daily basis. COD suffered a reduction of about 81% in the biological step and no increase was detected in the subsequent adsorption treatment. Overall removal efficiency was 76.6% and above 77.7% for LIN and HEP, respectively.

  5. Cycle length and COD/N ratio determine properties of aerobic granules treating high-nitrogen wastewater.

    Science.gov (United States)

    Cydzik-Kwiatkowska, Agnieszka; Bernat, Katarzyna; Zielińska, Magdalena; Wojnowska-Baryła, Irena

    2014-07-01

    Aerobic granule characteristic in sequencing batch reactors treating high-nitrogen digester supernatant was investigated at cycle lengths (t) of 6, 8 and 12 h with the COD/N ratios in the influent of 4.5 and 2.3. The biomass production (Y obs) correlated with the extracellular polymeric substances (EPS) in grams per COD removed. Denitrification efficiency significantly decreased as the amount of EPS in biomass increased, suggesting that organic assimilation in EPS hampers nitrogen removal. Granule hydrophobicity was highest at t of 8 h; the t has to be long enough to remove pollutants, but not so long that excessive biomass starvation causes extracellular protein consumption that decreases hydrophobicity. At a given t, reducing the COD/N ratio improved hydrophobicity that stimulates cell aggregation. At t of 6 h and the COD/N ratio of 2.3, the dominance of 0.5-1.0 mm granules favored simultaneous nitrification and denitrification and resulted in the highest nitrogen removal.

  6. Dissolved oxygen, COD, nitrogen and phosphorus profiles in a continuous sand filter used for WWTP effluent reclamation.

    Science.gov (United States)

    Xu, Hongbin; Scherrenberg, Sigrid M; van Lier, Jules B

    2012-01-01

    Continuous sand filtration (CSF) offers interesting potential for the extensive treatment of wastewater treatment plant (WWTP) effluents for water reclamation and/or restrictive discharge. Research on concentration profiles over the height of the CSF shows that most bacteriological conversions are restricted to the lower part of the filter bed. Dissolved oxygen (DO) rapidly decreases to below 1 mg/L in the first 0.4 m of the filter bed, applying hydraulic velocities of 12.9 ∼ 14.9 m/h and 10 ∼ 20 mm/min sand velocities, independent of the methanol dosage. The DO decrease agrees with the observed decrease in chemical oxygen demand (COD). At the given operational conditions, NO(x)-N and N-total removal is dedicated to the first 0.9 m of the filter bed. Results show that by optimising the CSF operational conditions the very restrictive effluent N and P values of 2.2 and 0.15 mg/L, respectively, as described in the European Water Framework Directive, can be met.

  7. Demanding Satisfaction

    Science.gov (United States)

    Oguntoyinbo, Lekan

    2010-01-01

    It was the kind of crisis most universities dread. In November 2006, a group of minority student leaders at Indiana University-Purdue University Indianapolis (IUPUI) threatened to sue the university if administrators did not heed demands that included providing more funding for multicultural student groups. This article discusses how this threat…

  8. Sequencing Batch Reactor (SBR) for the removal of Hg{sup 2+} and Cd{sup 2+} from synthetic petrochemical factory wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Malakahmad, Amirhossein, E-mail: amirhossein@petronas.com.my [Faculty of Energy and Environmental Studies, Islamic Azad University, Science and Research branch, Hesarak, Tehran (Iran, Islamic Republic of); Civil Engineering Department, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia); Hasani, Amirhesam [Faculty of Energy and Environmental Studies, Islamic Azad University, Science and Research branch, Hesarak, Tehran (Iran, Islamic Republic of); Eisakhani, Mahdieh [School of Social, Development and the Environment, Universiti Kebangsaan Malaysia, Bangi, Selangor (Malaysia); Isa, Mohamed Hasnain [Civil Engineering Department, Universiti Teknologi PETRONAS, Tronoh, Perak (Malaysia)

    2011-07-15

    Highlights: {yields} We assessed SBR performances to treat synthetic wastewater containing Hg{sup 2+} and Cd{sup 2+}. {yields} SBR was able to remove 76-90% of Hg{sup 2+} and 96-98% of Cd{sup 2+}. {yields} COD removal efficiency and MLVSS was affected by Hg{sup 2+} and Cd{sup 2+} concentrations. {yields} Removal was not only biological process but also by biosorption process of sludge. - Abstract: Petrochemical factories which manufacture vinyl chloride monomer and poly vinyl chloride (PVC) are among the largest industries which produce wastewater contains mercury and cadmium. The objective of this research is to evaluate the performance of a lab-scale Sequencing Batch Reactor (SBR) to treat a synthetic petrochemical wastewater containing mercury and cadmium. After acclimatization of the system which lasted 60 days, the SBR was introduced to mercury and cadmium in low concentrations which then was increased gradually to 9.03 {+-} 0.02 mg/L Hg and 15.52 {+-} 0.02 mg/L Cd until day 110. The SBR performance was assessed by measuring Chemical Oxygen Demand, Total and Volatile Suspended Solids as well as Sludge Volume Index. At maximum concentrations of the heavy metals, the SBR was able to remove 76-90% of Hg{sup 2+} and 96-98% of Cd{sup 2+}. The COD removal efficiency and MLVSS (microorganism population) in the SBR was affected by mercury and cadmium concentrations in influent. Different species of microorganisms such as Rhodospirilium-like bacteria, Gomphonema-like algae, and sulfate reducing-like bacteria were identified in the system. While COD removal efficiency and MLVSS concentration declined during addition of heavy metals, the appreciable performance of SBR in removal of Hg{sup 2+} and Cd{sup 2+} implies that the removal in SBR was not only a biological process, but also by the biosorption process of the sludge.

  9. Simultaneous nitrogen and organics removal using membrane aeration and effluent ultrafiltration in an anaerobic fluidized membrane bioreactor

    KAUST Repository

    Ye, Yaoli

    2017-08-03

    Dissolved methane and a lack of nutrient removal are two concerns for treatment of wastewater using anaerobic fluidized bed membrane bioreactors (AFMBRs). Membrane aerators were integrated into an AFMBR to form an Aeration membrane fluidized bed membrane bioreactor (AeMFMBR) capable of simultaneous removal of organic matter and ammonia without production of dissolved methane. Good effluent quality was obtained with no detectable suspended solids, 93±5% of chemical oxygen demand (COD) removal to 14±11 mg/L, and 74±8% of total ammonia (TA) removal to 12±3 mg-N/L for domestic wastewater (COD of 193±23 mg/L and TA of 49±5 mg-N/L) treatment. Nitrate and nitrite concentrations were always low (< 1 mg-N/L) during continuous flow treatment. Membrane fouling was well controlled by fluidization of the granular activated carbon (GAC) particles (transmembrane pressures maintained <3 kPa). Analysis of the microbial communities suggested that nitrogen removal was due to nitrification and denitrification based on the presence of microorganisms associated with these processes.

  10. Potential removal of biochemical pollutants in biofilters operating with domestic sewage

    Directory of Open Access Journals (Sweden)

    Maria Regilene de Freitas Costa Paiva

    2011-12-01

    Full Text Available The present study aimed to analyze the removal of Biochemical Oxygen Demand (BOD and Chemical Oxygen Demand (COD in biofilters operating with domestic sewage. Experimental tests were conducted at the Universidade Federal de Viçosa (UFV, Viçosa-MG. The experiment was a split split plot scheme, and in the plots different rates of sewage (0.5, 1.0 and 1.5 m3 m2 d-1 were applied, in the subplot, types of organic material (waste compost, sugar cane bagasse and sawdust were tested and in the subsubplots, five dates of measurements (August, September, October, November and December 2009 were evaluated, in a randomized block with three replications. Samples of domestic sewage were collected upstream and downstream of 27 biofilters for determination of BOD and COD, monthly for five months. The results showed that the effluent from biofilters meets the national standard for release in water streams, with regard to the BOD, after stabilization of the filter elements, and the use of biofilters for the treatment of domestic sewage is a viable technology for small scale because it has low cost, easy operation and good ability to remove biochemical pollutants.

  11. Dye Removal From Textile Waste Water Through The Adsorption By Pumice Used In Stone Washing

    Directory of Open Access Journals (Sweden)

    Körlü Aysegül Ekmekçi

    2015-09-01

    Full Text Available Because the waste production is inevitable in almost all industries, the elimination of these wastes is a requirement in terms of environmental regulations and welfare of all the creatures in the future. In this study, the use of the waste pumice stones of a denim washing mill is intended to eliminate the pollutant by a waste material and obtain economic benefits by converting it to the adsorbent. The pollutants in the effluents obtained from three different localisations of waste water treatment system of the same factory were removed through the adsorption. The experimental studies were carried out in three different steps; characterisation of adsorbent before and after adsorption; adsorption isotherm studies and biological oxygen demand (BOD, chemical oxygen demand (COD measurements. Characterisation studies showed that the waste pumice has almost the same structural properties with unused one except the existence of some organic residues coming from washing process. The results of adsorption studies conducted at the adsorbent concentrations changing from 5 to 35 g/l revealed that the decolourisation was initial dye-concentration dependent. According to the BOD and COD measurements, the supernatants obtained at the end of adsorption could be assumed as somewhat polluted and this result indicates that the organic impurities other than indigo were also removed through the adsorption.

  12. PENURUNAN NILAI COD PADA PESTISIDA SIPERMETRIN DENGAN FOTOKATALIS TITANIUM(IV OKSIDA-PLATINA

    Directory of Open Access Journals (Sweden)

    Diana Rakhmawaty Eddy

    2014-11-01

    Full Text Available Pada penelitian ini telah dilakukan fotodegradasi pestisida jenis sipermetrin dengan adanya fotokatalis titanium (IV oksida-platina. Fotokatalis tersebut dibuat dengan merefluks larutan titanium(IV oksida tetraminplatina(II klorida selama 2 jam kemudian diuapkan pelarutnya dan dipanaskan selama 12 jam. Padatan fotokatalis kemudian dikalsinasi selama 3 jam pada 500 °C. Hasil sintesis titanium(IV oksida-platina 0,5% dan 1% dikarakterisasi dengan XRD, SEM, dan SEM-EDX. Kemampuan dalam mengkatalisis fotodegradasi diuji untuk pestisida sipermetrin yang dilakukan selama 4 jam. Hasil fotodegradasi dinyatakan sebagai COD (Chemical Oxygen Demand yang diukur setiap 1 jam. Penurunan COD terbesar untuk titanium(IV oksida platina 0,5% dan titanium(IV oksida-platina 1% masing-masing yaitu 77% dan 79%. Sementara TiO2 standar sebesar 68,42 %. Fotokatalis titanium(IV oksida-platina lebih baik dibanding titanium(IV oksida untuk degradasi sipermetrin.

  13. The effect of electric pulse stimulation to juvenile cod and cod of commercial landing size

    NARCIS (Netherlands)

    Haan, de D.; Fosseidengen, J.E.; Fjelldal, P.G.; Burggraaf, D.

    2011-01-01

    The first pilot study on the effects of electric pulse stimulation on larger cod carried out in 2008 was based on a single nominal setting of the Verburg-Holland UK153 pulse system with the intention to determine the range of pulse characteristics with which injuries to the fish occurred. This study

  14. Cod farming at the intersection of fisheries and aquaculture

    OpenAIRE

    Aarset, Bernt; Standal, Dag; Asche, Frank

    2000-01-01

    Over the past three decades, the powerful combination of capital, research, and promising prospects has propelled salmon aquaculture to a mature, billion dollar, worldwide industry. Aquaculture entrepreneurs now search for new opportunities, but so far these attempts do not generate profit. Cod is targeted as a promising species, and here we explore the opportunities for the farming of cod. Two questions arise: (1) What characterizes cod as a farmed species? (2) How do these characteristics a...

  15. Improvement of anaerobic digestion performance by continuous nitrogen removal with a membrane contactor treating a substrate rich in ammonia and sulfide.

    Science.gov (United States)

    Lauterböck, B; Nikolausz, M; Lv, Z; Baumgartner, M; Liebhard, G; Fuchs, W

    2014-04-01

    The effect of reduced ammonia levels on anaerobic digestion was investigated. Two reactors were fed with slaughterhouse waste, one with a hollow fiber membrane contractor for ammonia removal and one without. Different organic loading rates (OLR) and free ammonia and sulfide concentrations were investigated. In the reactor with the membrane contactor, the NH4-N concentration was reduced threefold. At a moderate OLR (3.1 kg chemical oxygen demand - COD/m(3)/d), this reactor performed significantly better than the reference reactor. At high OLR (4.2 kg COD/m(3)/d), the reference reactor almost stopped producing methane (0.01 Nl/gCOD). The membrane reactor also showed a stable process with a methane yield of 0.23 Nl/g COD was achieved. Both reactors had predominantly a hydrogenotrophic microbial consortium, however in the membrane reactor the genus Methanosaeta (acetoclastic) was also detected. In general, all relevant parameters and the methanogenic consortium indicated improved anaerobic digestion of the reactor with the membrane.

  16. Nitrogen removal via nitrite from municipal landfill leachate

    Institute of Scientific and Technical Information of China (English)

    WU Lina; PENG Chengyao; ZHANG Shujun; PENG Yongzhen

    2009-01-01

    A system consisting of a two-stage up-flow anaerobic sludge blanket (UASB),an anoxic/aerobic (A/O) reactor and a sequencing batch reactor (SBR),was used to treat landfill leachate.During operation,denitrification and methanogenesis took place simultaneously in the first stage UASB (UASB1),and the effluent chemical oxygen demand (COD) was further removed in the second stage UASB (UASB2).Then the denitrification of nitrite and nitrate in the returned sludge by using the residual COD was accomplished in the A/O reactor,and ammonia was removed via nitrite in it.Last but not least,the residual ammonia was removed in SBR as well as nitrite and nitrate which were produced by nitrification.A system consisting of a two-stage UASB and an A/O reactor was used to achieve the stable short-cut nitrification in the first stage (60 d).The effluent of stage one was treated by SBR in the second stage (60 d).The results over 120 d were as follows: when the total nitrogen (TN) concentration of influent leachate was about 2500 mg/L and the ammonia nitrogen concentration was about 2000 mg/L,the short-cut nitrification with 85%-90% nitrite accumulation was achieved stably in the A/O reactor.The TN and ammonia nitrogen removal efficiencies of the system were 98% and 97%,respectively.The residual ammonia,nitrite and nitrate which were produced by nitrification in the A/O reactor could be washed out almost completely in SBR.The TN and ammonia nitrogen concentrations of final effluent were about 39 mg/L and 12 mg/L,respectively.

  17. Combined application of modified atmosphere packaging and superchilled storage to extend the shelf life of fresh cod (Gadus morhua) loins.

    Science.gov (United States)

    Wang, T; Sveinsdóttir, K; Magnússon, H; Martinsdóttir, E

    2008-01-01

    Development of new technologies and preservation methods to offer conveniently packed fish with sufficient keeping quality is important to meet increasing demand for value-added fresh fish products on the market. The aim of this study was to investigate the effect of combined application of modified atmosphere packaging (MAP) and superchilled storage on the shelf life of fresh cod loins. Fresh cod loins were packed in polystyrene boxes and in MA (CO(2)/N(2)/O(2): 50%/45%/5%) on day 3 postcatch and stored at chilled (1.5 degrees C) and superchilled (-0.9 degrees C) temperatures. Quantitative descriptive analysis (QDA) and physical, chemical, and microbial analyses were carried out during the 21 d of storage. Superchilled storage alone compared with traditional chilled storage in polystyrene boxes increased the total shelf life (days from catch) of cod loins from 9 to 16 or 17 d. Chilled MA packaging increased the shelf life from 9 to 14 d and when MAP and superchilled storage were combined, a synergistic effect was observed and the shelf life was further extended to at least 21 d. It is noteworthy that the characteristic fresh and sweet taste can be maintained longer under such conditions. This could contribute to enhanced eating quality of fresh cod fillets for consumers in distant markets. However, MAP combined with superchilled storage resulted in different textural properties. Superchilled MA packed cod loins had more meaty texture compared to other sample groups after 7-d storage.

  18. Correlating Biochemical and Chemical Oxygen Demand of Effluents

    African Journals Online (AJOL)

    F. K. Attiogbe1, Mary Glover-Amengor2 and K. T. Nyadziehe3

    oxygen demand (COD) of effluents from selected industries in the Kumasi Metropolis to ... comprehensiveness of the approach to solve the problem of wastewater disposal. .... GGL where higher BOD5 values were registered when spent yeast was .... Wastewater Engineering: Treatment, disposal and reuse, 3rd edn.

  19. Harvesting Atlantic Cod under Climate Variability

    Science.gov (United States)

    Oremus, K. L.

    2016-12-01

    Previous literature links the growth of a fishery to climate variability. This study uses an age-structured bioeconomic model to compare optimal harvest in the Gulf of Maine Atlantic cod fishery under a variable climate versus a static climate. The optimal harvest path depends on the relationship between fishery growth and the interest rate, with higher interest rates dictating greater harvests now at the cost of long-term stock sustainability. Given the time horizon of a single generation of fishermen under assumptions of a static climate, the model finds that the economically optimal management strategy is to harvest the entire stock in the short term and allow the fishery to collapse. However, if the biological growth of the fishery is assumed to vary with climate conditions, such as the North Atlantic Oscillation, there will always be pulses of high growth in the stock. During some of these high-growth years, the growth of the stock and its economic yield can exceed the growth rate of the economy even under high interest rates. This implies that it is not economically optimal to exhaust the New England cod fishery if NAO is included in the biological growth function. This finding may have theoretical implications for the management of other renewable yet exhaustible resources whose growth rates are subject to climate variability.

  20. Catalytic ozonation of organic pollutants from bio-treated dyeing and finishing wastewater using recycled waste iron shavings as a catalyst: Removal and pathways.

    Science.gov (United States)

    Wu, Jin; Ma, Luming; Chen, Yunlu; Cheng, Yunqin; Liu, Yan; Zha, Xiaosong

    2016-04-01

    Catalytic ozonation of organic pollutants from actual bio-treated dyeing and finishing wastewater (BDFW) with iron shavings was investigated. Catalytic ozonation effectively removed organic pollutants at initial pH values of 7.18-7.52, and the chemical oxygen demand (COD) level decreased from 142 to 70 mg·L(-1) with a discharge limitation of 80 mg·L(-1). A total of 100% and 42% of the proteins and polysaccharides, respectively, were removed with a decrease in their contribution to the soluble COD from 76% to 41%. Among the 218 organic species detected by liquid chromatography-mass spectrometry, 58, 77, 79 and 4 species were completely removed, partially removed, increased and newly generated, respectively. Species including textile auxiliaries and dye intermediates were detected by gas chromatography-mass spectrometry. The inhibitory effect decreased from 51% to 33%, suggesting a reduction in the acute toxicity. The enhanced effect was due to hydroxyl radical (OH) oxidation, co-precipitation and oxidation by other oxidants. The proteins were removed by OH oxidation (6%), by direct ozonation, co-precipitation and oxidation by other oxidants (94%). The corresponding values for polysaccharides were 21% and 21%, respectively. In addition, the iron shavings behaved well in successive runs. These results indicated that the process was favorable for engineering applications for removal of organic pollutants from BDFW.

  1. OPTIMASI PENURUNAN NILAI BOD, COD DAN TSS LIMBAH CAIR INDUSTRI TAPIOKA MENGGUNAKAN ARANG AKTIF DARI AMPAS KOPI

    Directory of Open Access Journals (Sweden)

    Irmanto

    2010-05-01

    Full Text Available Activated carbon from coffee dregs for TSS, BOD and COD removal of tapioca industrial wastewater has been developed. The research aimed to know the quality of activated carbon from dregs of coffee as adsorbent, consist of total rendemen, water content, ashes content and iodium adsorption; to know about the optimum contact time and optimum pH from activated carbon on reducing BOD, COD and TSS value from tapioca industrial wastewater and also to know about the decrease percentage of BOD, COD and TSS value using activated carbon from dregs of coffee. Activated carbon from dregs of coffee are activated using HCl 0,1 N and carbonization at 350°C in muffle furnace. Then, activated carbon was contacted with the tapioca industrial wastewater and used on decreasing BOD, COD and TSS value from tapioca industrial wastewater with contact time varieties 0, 10, 30, 60, 90 and 120 minutes and at pH varieties of wastewater 4, 5, 6, 7, 8, 9 and 10. The decreasing of BOD value was measured by Winkler method, decreasing of COD value measured by iodometric method and decreasing of TSS value measured by gravimetric method. The result of the research showed that the activated carbon produced characteristic consist of rendemen 14,55%; water content 3,4%; ashes content 1,88% and iodium adsorption 750,25 mg/g. It is indicated that the activated carbon that is got from dregs of coffee fulfill the criteria required by SNI No. 06-3730-1995. The result of research also showed that the activated carbon from dregs of coffee could be used for reducing the BOD, COD and TSS value in tapioca industrial wastewater at the optimum contact time of 30 minutes and pH 7. The optimum percentage of activated carbon from dregs of coffee in decreasing BOD value of tapioca industrial wastewater are 33,51%; COD value 78,96% and TSS value 61,05%.

  2. Demand Uncertainty

    DEFF Research Database (Denmark)

    Nguyen, Daniel Xuyen

    This paper presents a model of trade that explains why firms wait to export and why many exporters fail. Firms face uncertain demands that are only realized after the firm enters the destination. The model retools the timing of uncertainty resolution found in productivity heterogeneity models...... the high rate of exit seen in the first years of exporting. Finally, when faced with multiple countries in which to export, some firms will choose to sequentially export in order to slowly learn more about its chances for success in untested markets....

  3. Removal of Furfural From Wastewater Using Integrated Catalytic Ozonation and Biological Approaches

    Directory of Open Access Journals (Sweden)

    Mostafa Leili

    2014-12-01

    Full Text Available Furfural with a chemical formula of C5H4O2 is a toxic compound which has several health problems for both humans and environment. It has a few exposure routes for entering the human body such as oral, dermal or nasal. In the present study, the efficacies of an integrated catalytic ozonation process (COP and novel cyclic biological reactor (CBR were explored for the removal of furfural from aqueous solutions. Activated carbon was purchased from Merck Company. It had a Brunauer, Emmett, and Teller (BET specific surface area of 1100 m2/g, with an average micropore volume and size of 0.385 cm3/g and 595 µm, respectively. The results indicated that 30% pretreatment with COP could increase furfural and chemical oxygen demand (COD removal efficiency with CBR 5.56% and 27.01%, respectively. With 70% pretreatment by COP, 98.57% furfural and 95.34% COD removal efficiencies happen in CBR. Generally, batch and continuous experiments showed that the integrated COP/CBR could be efficient in eliminating furfural from wastewater and thus may be a promising technique for treating furfural-containing wastewater.

  4. Chemical oxygen demand, total organic carbon and colour reduction in slaughterhouse wastewater by unmodified and iron-modified clinoptilolite-rich tuff.

    Science.gov (United States)

    Torres-Pérez, J; Solache-Ríos, M; Martínez-Miranda, V

    2014-01-01

    In this study, reduction of chemical oxygen demand (COD), colour, and total organic carbon in effluents from a slaughterhouse in central Mexico was performed using clinoptilolite-rich tuff. The experimental parameters considered were initial concentration of the adsorbate, pH, adsorbent dosage, and contact time. Surface morphology of the materials was tested by using scanning electron microscopy. Specific surface area was analysed by using Brunauer-Emmett-Teller (BET) and phase composition was analysed by using X-ray diffraction. The experimental adsorption data were fitted to the first- and pseudo-second-order kinetic models. The highest COD removal was observed in slightly acidic pH conditions. The maximum reduction efficiency of COD was accomplished with unmodified clinoptilolite-rich tuff at a contact time of 1440 min. In these conditions, the adsorbent was efficient for treating wastewater from a slaughterhouse. Moreover, after several regeneration cycles with Fenton reagent or hydrogen peroxide, the regenerated zeolite with H2O2 (3%) showed the best reduction efficiencies.

  5. Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Velasco, Antonio [Direccion General del Centro Nacional de Investigacion y Capacitacion Ambiental-Instituto Nacional de Ecologia, Av. San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico)], E-mail: jvelasco@ine.gob.mx; Ramirez, Martha [Direccion General del Centro Nacional de Investigacion y Capacitacion Ambiental-Instituto Nacional de Ecologia, Av. San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Volke-Sepulveda, Tania [Departamento de Biotecnologia, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Gonzalez-Sanchez, Armando [Departamento de Ingenieria de Procesos, Universidad Autonoma Metropolitana-Iztapalapa, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Revah, Sergio [Departamento de Procesos y Tecnologia, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico)

    2008-03-01

    The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO{sub 4}{sup 2-} ratio. This work relates the feed COD/SO{sub 4}{sup 2-} ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470 {+-} 7 mg S/L was obtained at a feed COD/SO{sub 4}{sup 2-} ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145 {+-} 10 mg S/L) was observed with a feed COD/SO{sub 4}{sup 2-} ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO{sub 4}{sup 2-} ratio of 1.5. It was found that the feed COD/SO{sub 4}{sup 2-} ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead.

  6. Removal of high organic loads from winery wastewater by aquatic plants.

    Science.gov (United States)

    Zimmels, Y; Kirzhner, F; Schreiber, J

    2008-09-01

    Laboratory- and field-scale purification tests of raw and diluted winery wastewater (WWW) were carried out using aquatic plants at high organic loads. The laboratory tests were performed using artificial light at 1800 to 1900 lux. The objective of the current study was to define the potential of floating and emergent aquatic macrophytes and the microorganisms attached to their roots, to reduce high organic loads that characterize WWW, thereby providing, for these effluents, an effective treatment and management system. These microorganisms are believed to have a major role in the treatment process. In this context, the potential of floating and emergent macrophytes to improve the water quality of raw compared with diluted WWW was evaluated. In raw WWW (chemical oxygen demand [COD] 5.6 g/L),growth inhibition of both water hyacinth (Eichhornia crassipes) and water pennywort (Hydrocotyle umbellata) was observed. A 1:1 dilution of WWW with fresh (tap) water facilitated growth of these plants. At this dilution level, growth of pennywort was limited, while that of water hyacinth was robust. In terms of reductions in biochemical oxygen demand, COD, and total suspended solids, both water hyacinth and pennywort performed better in diluted compared with raw WWW. At 1:1 and 1:3 dilution, 95.9 to 97% of the COD was removed after 23 days, in the presence of Hydrocotyle and Eichhornia plants and aeration. The capacity of new emergent plants to remove high organic loads from WWW, at enhanced kinetics, was demonstrated. This unique property was tested and compared with the role of the gravel media that support growth of the high-capacity emergent plants. In the presence of reed and salt marsh plants, 83 to 99% of the COD was removed within a period of 24 to 29 days, at 1.5:1 dilution. The new emergent plants proved to be effective, even at record high levels of COD. At an initial level of 16,460 mg/L, the COD was brought down to 2870 mg/L after 24 days (82.6% removal), while 12

  7. Hydrogeologic framework of western Cape Cod, Massachusetts

    Science.gov (United States)

    Masterson, John P.; Stone, Byron D.; Walter, Donald A.; Savoie, Jennifer G.

    1997-01-01

    The aquifer of western Cape Cod consists of several hydrogeologic units composed of sand, gravel, silt, and clay (fig. 1) that were deposited during the late Wisconsinan glaciation of New England. The aquifer is a shallow, unconfined hydrologic system in which ground-water flows radially outward from the apex of the ground-water mound near the center of the peninsula toward the coast (fig.2). The aquifer is the sole source of water supply for the towns of Bourne, Sandwich, Falmouth, and Mashpee, and the Massachusetts Military Reservation (MMR).Previous geologic studies summarized the characteristics and relative ages of the glacial moraines and meltwater deposits and the relation of these sediments to the extent of the ice-sheet lobes during the last glaciation of southern New England (Oldale and Barlow, 1986; Hartshorn and others, 1991). Hydrogeologic studies in western Cape Cod characterized the shallow regional ground-water-flow system (LeBlanc and others, 1986) and analyzed simulated responses of the aquifer to changes in hydrologic stresses (Guswa and LeBlanc, 1985; Barlow and Hess, 1993; Masterson and Barlow, 1994; and Masterson and others, 1996). Recent concerns about widespread ground-water contamination, especially from sources on the MMR, have resulted in extensive investigations to characterize the local hydrogeology of the aquifer near the MMR (ABB Environmental Services, 1992). Masterson and others (1996) illustrated the strong influence of geology on ground-water flow and the importance of characterizing the hydrogeology to predict the migration of the contaminant plumes beneath the MMR.This report, a product of a cooperative study between the National Guard Bureau and the U.S. Geological Survey (USGS), characterizes the regional hydrogeology of the western Cape Cod aquifer on the basis of surficial glacial geology previously described by Mather and others (1940) and Oldale and Barlow (1986), and presents a new analysis of the subsurface hydrogeology

  8. Advanced nitrogen removal using pilot-scale SBR with intelligent control system built on three layer network

    Institute of Scientific and Technical Information of China (English)

    YANG Qing; WANG Shuying; YANG Anming; GUO Jianhua; BO Fengyang

    2007-01-01

    Since eutrophication has become increasingly severe in China,nitrogen and phosphorous have been the concern of wastewater treatment,especially nitrogen removal.The stabilization of the intelligent control system and nitrogen removal efficiency were investigated in a pilot-scale aerobic-anoxic sequencing batch reactor(SBR)with a treatment capacity of 60 m3/d.Characteristic points on the profiles of dissolved oxygen(DO),pH,and oxidation reduction potential(ORP)could exactly reflect the process of nitrification and denitrification.Using the intelligent control system not only could save energy,but also could achieve advanced nitrogen removal.Applying the control strategy water quality of the effluent could stably meet the national first discharge standard during experiment of 10 months.Even at low temperature(t=13℃),chemical oxygen demand(COD)and total nitrogen(TY)in the effluent were under 50 and 5 mg/L,respectively.

  9. Removal and recycling of pollutants from Hong Kong restaurant wastewaters.

    Science.gov (United States)

    Chan, H

    2010-09-01

    Most restaurant operators in Hong Kong run their business in commercial buildings. Many of them fail to meet oil and grease (O & G) limits. The O & G and Chemical Oxygen Demand (COD) content of the effluents can be reduced to meet government prescribed standards using a combination of compressed air and chemical treatment in existing two-chamber grease traps. A mean level of 41 mg/L and a mean removal of 92.7% of O & G can be achieved for a typical fast food restaurant. COD reduction can further be improved by dissolved air flotation enhanced with chemicals. Sludge generated from flotation treatment of the wastewaters can be recycled as a fertilizer to give a mean total nitrogen content of 13,217 mg/kg and a mean total phosphorus level of 1133 mg/kg. Moreover, it can also be utilized as a biofuel to give a mean calorific value of 6690 Cal/g which is equivalent to that of coal. (c) 2010 Elsevier Ltd. All rights reserved.

  10. Aerobic granules formation and simultaneous nitrogen and phosphorus removal treating high strength ammonia wastewater in sequencing batch reactor.

    Science.gov (United States)

    Wei, Dong; Shi, Li; Yan, Tao; Zhang, Ge; Wang, Yifan; Du, Bin

    2014-11-01

    The objective of this study was to evaluate aerobic granules formation and simultaneous nitrogen and phosphorus removal treating high strength ammonia wastewater in sequencing batch reactor (SBR). After successful aerobic granulation, mixed liquor suspended solids (MLSS) concentrations of the SBR increased from 3.11 to 14.52 g/L, while sludge volume index (SVI) values decreased from 144.61 to 30.32 mL/g. Protein (PN) and polysaccharide (PS) concentrations increased from 60.2 and 12.5 mg/L to 101.1 and 15.8 mg/L, respectively. Simultaneous nitrogen and phosphorus removal was enhanced by altering the influent chemical oxygen demand/nitrogen (COD/N) ratio. At COD/N ratio of 9, total nitrogen (TN) and total phosphorus (TP) removal efficiencies were up to 89.8% and 77.5%, respectively. Three-dimensional excitation-emission matrix (3D-EEM) spectroscopy showed that the chemical compositions of sludge EPS were changed during granulation process. The results could provide useful information to promote nitrogen and phosphorus removal using aerobic granular sludge technology.

  11. 78 FR 41305 - Collect on Delivery (COD)-Service Features

    Science.gov (United States)

    2013-07-10

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE 39 CFR Part 111 Collect on Delivery (COD)--Service Features AGENCY: Postal Service TM . ACTION: Final rule... proposed rule were received, the Postal Service will adopt the proposed changes to Collect on Delivery (COD...

  12. Rationale for restocking the Eastern Baltic cod stock

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Overton, Julia Lynne; Paulsen, Helge

    2008-01-01

    The Danish Institute for Fisheries Research and Bornholm's Salmon Hatchery examined the potential for restocking Baltic cod (Gadus morhua callarias L.) in the eastern Baltic Sea. This cod population has adapted to the unique brackish water conditions where successful spawning depends on regular i...

  13. 33 CFR 117.589 - Cape Cod Canal.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Cape Cod Canal. 117.589 Section 117.589 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES DRAWBRIDGE OPERATION REGULATIONS Specific Requirements Massachusetts § 117.589 Cape Cod Canal. The draw of the Conrail railroad bridge, mile 0.7 at...

  14. Could seals prevent cod recovery in the Baltic Sea?

    Directory of Open Access Journals (Sweden)

    Brian R MacKenzie

    Full Text Available Fish populations are increasingly affected by multiple human and natural impacts including exploitation, eutrophication, habitat alteration and climate change. As a result many collapsed populations may have to recover in ecosystems whose structure and functioning differ from those in which they were formerly productive and supported sustainable fisheries. Here we investigate how a cod (Gadus morhua population in the Baltic Sea whose biomass was reduced due to a combination of high exploitation and deteriorating environmental conditions might recover and develop in the 21st century in an ecosystem that likely will change due to both the already started recovery of a cod predator, the grey seal Halichoerus grypus, and projected climate impacts. Simulation modelling, assuming increased seal predation, fishing levels consistent with management plan targets and stable salinity, shows that the cod population could reach high levels well above the long-term average. Scenarios with similar seal and fishing levels but with 15% lower salinity suggest that the Baltic will still be able to support a cod population which can sustain a fishery, but biomass and yields will be lower. At present knowledge of cod and seal interactions, seal predation was found to have much lower impact on cod recovery, compared to the effects of exploitation and salinity. These results suggest that dual management objectives (recovery of both seal and cod populations are realistic but success in achieving these goals will also depend on how climate change affects cod recruitment.

  15. Analytical determination of Chemical Oxygen Demand in samples considered to be difficult to analyse: solid substrates and liquid samples with high suspended solid concentrations

    DEFF Research Database (Denmark)

    Raposo, Francisco; Fernández-Cegrí, V.; De la Rubia, M.A.

    Chemical oxygen demand (COD) is a critical analytical parameter in the field of waste and wastewater treatment processes, and more specifically in anaerobic digestion processes. However, little is known about the COD measurement quality of anaerobic digestion samples. Taking into account the lack...... PTs related with COD determination have been organised, and the results reported have been compared; showing the importance of continuous participation in proficiency testing (PT) schemes in order to improve the results obtained....

  16. Photocatalytic Membrane Reactor for the Removal of C.I. Disperse Red 73

    Directory of Open Access Journals (Sweden)

    Valentina Buscio

    2015-06-01

    Full Text Available After the dyeing process, part of the dyes used to color textile materials are not fixed into the substrate and are discharged into wastewater as residual dyes. In this study, a heterogeneous photocatalytic process combined with microfiltration has been investigated for the removal of C.I. Disperse Red 73 from synthetic textile effluents. The titanium dioxide (TiO2 Aeroxide P25 was selected as photocatalyst. The photocatalytic treatment achieved between 60% and 90% of dye degradation and up to 98% chemical oxygen demand (COD removal. The influence of different parameters on photocatalytic degradation was studied: pH, initial photocatalyst loading, and dye concentration. The best conditions for dye degradation were pH 4, an initial dye concentration of 50 mg·L−1, and a TiO2 loading of 2 g·L−1. The photocatalytic membrane treatment provided a high quality permeate, which can be reused.

  17. STUDY ON THE RELATIONSHIP BETWEEN J-INTEGRAL AND COD

    Institute of Scientific and Technical Information of China (English)

    Y. G. Cao; X. Y. Sun; K. Tanaka

    2007-01-01

    J-integral and crack opening displacement δ (COD) were important parameters for characterizationof fractures in engineering materials. The relationship between J-integral and COD has beeninvestigated for a long time and was generally represented as J = mσyδ, where σy is the yield strengthand m is a function of specimen geometry and material properties. To determine the value of m,extensive studies and experiments have been performed. The method that used the fracture-surfacetopography analysis (FRASTA) for determining J-integral from fracture surfaces of materials wasintroduced. On the basis of the relationship between COD and fracture surface average profile,the relationship between J-integral and COD was deduced and compared with the generally usedequation. The method was experimentally confirmed to be able to provide a new way to determinethe relationship between J-integral and COD.

  18. Identification and Metabolic Mechanism of Non-fermentative Short-cut Denitrifying Phosphorus-removing Bacteria

    Institute of Scientific and Technical Information of China (English)

    LIU Hui; SUN Yanfu; JIA Xiaoshan; LI Jun; ZHOU Kangqun; QU Xiangdong; TAO Xueqin

    2013-01-01

    To investigate the characteristics and metabolic mechanism of short-cut denitrifying phosphorus-removing bacteria (SDPB) that are capable of enhanced biological phosphorus removal (EBPR) using nitrite as an electron acceptor,an aerobic/anoxic sequencing batch reactor was operated under three phases.An SDPB-strain YC was screened after the sludge enrichment and was identified by morphological,physiological,biochemical properties and 16S rDNA gene sequence analysis.Denitrifying phosphorus-removing experiments were conducted to study anaerobic and anoxic metabolic mechanisms by analyzing the changes of chemical oxygen demand (COD),phosphate,nitrite,poly-fβ-hydroxybutyrate (PHB),and glycogen.The results show that strain YC is a non-fermentative SDPB similar to Paracoccus denitrificans.As a kind of non-fermentative bacteria,the energy of strain YC was mainly generated from phosphorus release (96.2%) under anaerobic conditions with 0.32 mg P per mg synthesized PHB.Under anoxic conditions,strain YC accumulated 0.45 mg P per mg degraded PHB,which produced most of energy for phosphate accumulation (91.3%) and a little for glycogen synthesis (8.7%).This metabolic mechanism of strain YC is different from that of traditional phosphorus-accumulating organisms (PAOs).It is also found that PHB,a kind of intracellular polymer,plays a very important role in denitrifying and accumulating phosphorus by supplying sufficient energy for phosphorous accumulation and carbon sources for denitrification.Therefore,monitoring △P/△PHB and △NO2--N/△PHB is more necessary than monitoring △P/△COD,△NO2--N/△COD,or △P/△NO2--N.

  19. Determining COD Load of Cattle Dung and Calculating COD Formation Coefficient and Total COD Amount Engendered from Cattle Dung in China%牛粪COD负荷、产污系数及原始产污总量的测算

    Institute of Scientific and Technical Information of China (English)

    张蓓; 李汉平; 张春光

    2011-01-01

    为得到牛粪COD产污系数及原始产污总量,先采用非水样品COD负荷测定方法,对单位绝干牛粪COD负荷值进行了实验测定:牛粪(含溶解态和非溶解态的全成分样)的COD负荷实测值为1.337 kg·kg-1(绝干牛粪).由排粪系数得到牛粪的COD产污系数典型值为5.35kg·d-1·头-1.根据养牛数,计算得到我国2008年牛粪的COD原始产污总量高达2.06亿t,相当于当年全国工业和生活COD排放总量的15.6倍.需要对牛粪的GOD原始产污总量与可能形成的水环境面源贡献压力及其防范予以充分重视.%Based on the established COD (Chemical Oxygen Demand) determination method to non-aqueous samples such as crop straws, several COD load experiments on cattle dung were carried out, in which the samples of cattle dung were firstly dissolved in the solution of 75 % sulphuric acid before using the COD determination method to waste water samples. The results showed that the determination method of COD load on cattle dung was feasible in practice, and were both exact and reliable. According to the experiment, the average COD load was 1.337 kg · kg-1 ( oven dry cattle dung). The COD formation coefficient from cattle dung was 5.35 kg · d-1 · cattle -1. With the statistical data on cattle, total COD amount directly engendered from cattle dung in China was about 206 million tons in 2008, which was 15.6 times to the total COD amount discharged from all industries and urban population in 2008, China. And the COD amount formed from cattle dung in the form of non-point sources had a positive linear relationship with the lost rate of total cattle dung amount emitted into the receiving waters. Therefore, more attentions should be paid on preventing and managing water environmental issues due to the cattle dung in China.

  20. Arsenic removal in a sulfidogenic fixed-bed column bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Altun, Muslum, E-mail: muslumaltun@hotmail.com [Hacettepe University, Department of Chemistry, Beytepe, Ankara (Turkey); Sahinkaya, Erkan [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey); Durukan, Ilknur; Bektas, Sema [Hacettepe University, Department of Chemistry, Beytepe, Ankara (Turkey); Komnitsas, Kostas [Technical University of Crete, Department of Mineral Resources Engineering, Chania (Greece)

    2014-03-01

    Highlights: • Sulfidogenic treatment of As-containing AMD was investigated. • High rate simultaneous removal of As and Fe was achieved. • As was removed without adding alkalinity or adjusting pH. • As and Fe removal mechanisms were elucidated. - Abstract: In the present study, the bioremoval of arsenic from synthetic acidic wastewater containing arsenate (As{sup 5+}) (0.5–20 mg/L), ferrous iron (Fe{sup 2+}) (100–200 mg/L) and sulfate (2000 mg/L) was investigated in an ethanol fed (780–1560 mg/L chemical oxygen demand (COD)) anaerobic up-flow fixed bed column bioreactor at constant hydraulic retention time (HRT) of 9.6 h. Arsenic removal efficiency was low and averaged 8% in case iron was not supplemented to the synthetic wastewater. Neutral to slightly alkaline pH and high sulfide concentration in the bioreactor retarded the precipitation of arsenic. Addition of 100 mg/L Fe{sup 2+} increased arsenic removal efficiency to 63%. Further increase of influent Fe{sup 2+} concentration to 200 mg/L improved arsenic removal to 85%. Decrease of influent COD concentration to its half, 780 mg/L, resulted in further increase of As removal to 96% when Fe{sup 2+} and As{sup 5+} concentrations remained at 200 mg/L and 20 mg/L, respectively. As a result of the sulfidogenic activity in the bioreactor the effluent pH and alkalinity concentration averaged 7.4 ± 0.2 and 1736 ± 239 mg CaCO{sub 3}/L respectively. Electron flow from ethanol to sulfate averaged 72 ± 10%. X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses were carried out to identify the nature of the precipitate generated by sulfate reducing bacteria (SRB) activity. Precipitation of arsenic in the form of As{sub 2}S{sub 3} (orpiment) and co-precipitation with ferrous sulfide (FeS), pyrite (FeS{sub 2}) or arsenopyrite (FeAsS) were the main arsenic removal mechanisms.

  1. Temperature, plant species and residence time effects on nitrogen removal in model treatment wetlands.

    Science.gov (United States)

    Allen, C R; Stein, O R; Hook, P B; Burr, M D; Parker, A E; Hafla, E C

    2013-01-01

    Total nitrogen (TN) removal in treatment wetlands (TWs) is challenging due to nitrogen cycle complexity and the variation of influent nitrogen species. Plant species, season, temperature and hydraulic loading most likely influence root zone oxygenation and appurtenant nitrogen removal, especially for ammonium-rich wastewater. Nitrogen data were collected from two experiments utilizing batch-loaded (3-, 6-, 9- and 20-day residence times), sub-surface TWs monitored for at least one year during which temperature was varied between 4 and 24 °C. Synthetic wastewater containing 17 mg/l N as NH4 and 27 mg/l amino-N, 450 mg/l chemical oxygen demand (COD), and 13 mg/l SO4-S was applied to four replicates of Carex utriculata, Schoenoplectus acutus and Typha latifolia and unplanted controls. Plant presence and species had a greater effect on TN removal than temperature or residence time. Planted columns achieved approximately twice the nitrogen removal of unplanted controls (40-95% versus 20-50% removal) regardless of season and temperature. TWs planted with Carex outperformed both Typha and Schoenoplectus and demonstrated less temperature dependency. TN removal with Carex was excellent at all temperatures and residence times; Schoenoplectus and Typha TN removal improved at longer residence times. Reductions in TN were not accompanied by increases in NO3, which was consistently below 1 mg/l N.

  2. Reducing COD level on oily effluent by utilizing biosurfactant-producing bacteria

    Directory of Open Access Journals (Sweden)

    Daniela Franco Carvalho Jacobucci

    2009-08-01

    Full Text Available Two bacteria isolated from crude oil contaminated soil, Pantoea agglomerans and Planococcus citreus, produced biosurfactants utilizing 1.5% of kerosene and olive oil as the sole carbon sources, respectively. The bacteria and the biosurfactants produced were introduced to oily effluent, arising from margarine and soap industry. Emulsification activities were determined by increases in the absorbance of the oil-in-water emulsions at 610 nm, whereas the water-in-oil emulsions were expressed as the height (cm of the emulsion layers formed. The 72 h incubation experiment resulted in a COD (Chemical Oxygen Demand reduction of 76% with Planococcus citreus strain and 70% with Pantoea agglomerans.The COD reduction with bacterial biosurfactants was over 50% in 24 h of incubation. The COD reduction showed that these strains and the surfactants produced could be used in bioremediation processes.Duas bactérias isoladas de solo contaminado com derivados de petróleo, Pantoea agglomerans e Planococcus citreus, produzem biosurfactantes utilizando respectivamente 1.5% de querosene e óleo de oliva como únicas fontes de carbono. As bactérias e os biosurfactantes produzidos foram adicionados a um efluente oleoso obtido de uma indústria nacional de sabão e margarina. As atividades de emulsificação foram determinadas pelo aumento da absorbância das emulsões óleo em água a 610 nm, enquanto que as emulsões do tipo água em óleo foram expressas em centímetros, pela altura do halo de espumas formado. A redução da demanda química de oxigênio (COD mostra que as linhagens e os biosurfactantes produzidos podem ser utilizados em processos de biorremediação.

  3. Removal of an endocrine disrupting chemical (17 alpha-ethinyloestradiol) from wastewater effluent by activated carbon adsorption: Effects of activated carbon type and competitive adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Ifelebuegu, A.O.; Lester, J.N.; Churchley, J.; Cartmell, E. [Cranfield University, Cranfield (United Kingdom). School of Water Science

    2006-12-15

    Granular activated carbon has been extensively used for the adsorption of organic micropollutants for potable water production. In this study the removal of an endocrine disrupting chemical from wastewater final effluent by three types of granular activated carbon (wood, coconut and coal based) has been investigated in batch adsorption experiments and correlated with the removal of chemical oxygen demand (COD), total organic carbon (TOC) and ultraviolet absorbance (UV). The results obtained demonstrated 17 alpha-ethinyloestradiol (EE2) removals of 98.6%, 99.3%, and 96.4% were achieved by the coal based (ACo), coconut based (ACn) and wood based (AWd) carbons respectively at the lowest dose of carbon (0.1 gl{sup -1}). The other adsorbates investigated all exhibited good removal. At an equilibrium concentration of 7 mgl{sup -1} the COD adsorption capacities were 3.16 mg g{sup -1}, 4.8 mg g{sup -1} and 7.1 mg g{sup -1} for the wood, coconut and coal based carbons respectively. Overall, the order of removal efficiency of EE2 and the other adsorbates for the three activated carbons was ACn {gt} ACo {gt} AWd. The adsorption capacities of the carbons were found to be reduced by the effects of other competing adsorbates in the wastewater effluent.

  4. Biological Nutrient Removal in a Full Scale Anoxic/Anaerobic/Aerobic/Pre-anoxic-MBR Plant for Low C/N Ratio Municipal Wastewater Treatment

    Institute of Scientific and Technical Information of China (English)

    胡香; 谢丽; 张善发; 杨殿海

    2014-01-01

    A novel full scale modified A2O (anoxic/anaerobic/aerobic/pre-anoxic)-membrane bioreactor (MBR) plant combined with the step feed strategy was operated to improve the biological nutrient removal (BNR) from low C/N ratio municipal wastewater in Southern China. Transformation of organic carbon, nitrogen and phosphorus, and membrane fouling were investigated. Experimental results for over four months demonstrated good efficiencies for chemical oxygen demand (COD) and 4NH+-N removal, with average values higher than 84.5%and 98.1%, re-spectively. A relatively higher total nitrogen (TN) removal efficiency (52.1%) was also obtained at low C/N ratio of 3.82, contributed by the configuration modification (anoxic zone before anaerobic zone) and the step feed with a distribution ratio of 1︰1. Addition of sodium acetate into the anoxic zone as the external carbon source, with a theoretical amount of 31.3 mg COD per liter in influent, enhanced denitrification and the TN removal efficiency in-creased to 74.9%. Moreover, the total phosphate (TP) removal efficiency increased by 18.0%. It is suggested that the external carbon source is needed to improve the BNR performance in treating low C/N ratio municipal waste-water in the modified A2O-MBR process.

  5. Simultaneous nitrogen and phosphorus removal in the sulfur cycle-associated Enhanced Biological Phosphorus Removal (EBPR) process.

    Science.gov (United States)

    Wu, Di; Ekama, George A; Wang, Hai-Guang; Wei, Li; Lu, Hui; Chui, Ho-Kwong; Liu, Wen-Tso; Brdjanovic, Damir; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2014-02-01

    Hong Kong has practiced seawater toilet flushing since 1958, saving 750,000 m(3) of freshwater every day. A high sulfate-to-COD ratio (>1.25 mg SO4(2-)/mg COD) in the saline sewage resulting from this practice has enabled us to develop the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process with minimal sludge production and oxygen demand. Recently, the SANI(®) process has been expanded to include Enhanced Biological Phosphorus Removal (EBPR) in an alternating anaerobic/limited-oxygen (LOS-EBPR) aerobic sequencing batch reactor (SBR). This paper presents further development - an anaerobic/anoxic denitrifying sulfur cycle-associated EBPR, named as DS-EBPR, bioprocess in an alternating anaerobic/anoxic SBR for simultaneous removal of organics, nitrogen and phosphorus. The 211 day SBR operation confirmed the sulfur cycle-associated biological phosphorus uptake utilizing nitrate as electron acceptor. This new bioprocess cannot only reduce operation time but also enhance volumetric loading of SBR compared with the LOS-EBPR. The DS-EBPR process performed well at high temperatures of 30 °C and a high salinity of 20% seawater. A synergistic relationship may exist between sulfur cycle and biological phosphorus removal as the optimal ratio of P-release to SO4(2-)-reduction is close to 1.0 mg P/mg S. There were no conventional PAOs in the sludge. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Application of response surface methodology to optimize the operational parameters for enhanced removal efficiency of organic matter and nitrogen: moving bed biofilm reactor.

    Science.gov (United States)

    Barwal, Anjali; Chaudhary, Rubina

    2016-05-01

    An attempt of response surface methodology (RSM) has been made for more effective utilization and optimization for considerable reduction of operational conditions such as reaction time, aeration time, energy consumption, etc. for municipal wastewater treatment process using moving bed biofilm reactor (MBBR). A mathematical-statistical model was developed for the second-order response surface through the fit of a polynomial function and a central composite design (CCD) in the form of a full factorial design. CCD was employed to assess the interactive effects of the three main independent operational parameters, including biocarrier filling rate (0-70 %), aeration rate (0.21-0.42 m(3) h(-1)), and reactor run time (1-15 days), on the removal efficiency of chemical oxygen demand (COD), biochemical oxygen demand (BOD), and total Kjeldahl nitrogen (TKN). Analysis of variance expressed a high coefficient of determination (R (2) = 0.84-0.95), thereby indicating that the model is significant. Using a desirability function for the highest COD (93 %), BOD (96 %), and TKN (69 %) removal, the optimum carrier filling rate, aeration rate, and reactor run time were identified to be 40 %, 0.21 m(3) h(-1), and 7 days, respectively. It shows that RSM can be a suitable method to optimize the operational parameters of MBBR with enhanced removal efficiency and less power consumption.

  7. A sequencing batch reactor system for high-level biological nitrogen and phosphorus removal from abattoir wastewater.

    Science.gov (United States)

    Lemaire, Romain; Yuan, Zhiguo; Bernet, Nicolas; Marcos, Marcelino; Yilmaz, Gulsum; Keller, Jürg

    2009-06-01

    A sequencing batch reactor (SBR) system is demonstrated to biologically remove nitrogen, phosphorus and chemical oxygen demand (COD) to very low levels from abattoir wastewater. Each 6 h cycle contained three anoxic/anaerobic and aerobic sub-cycles with wastewater fed at the beginning of each anoxic/anaerobic period. The step-feed strategy was applied to avoid high-level build-up of nitrate or nitrite during nitrification, and therefore to facilitate the creation of anaerobic conditions required for biological phosphorus removal. A high degree removal of total phosphorus (>98%), total nitrogen (>97%) and total COD (>95%) was consistently and reliably achieved after a 3-month start-up period. The concentrations of total phosphate and inorganic nitrogen in the effluent were consistently lower than 0.2 mg P l(-1) and 8 mg N l(-1), respectively. Fluorescence in situ hybridization revealed that the sludge was enriched in Accumulibacter spp. (20-40%), a known polyphosphate accumulating organism, whereas the known glycogen accumulating organisms were almost absent. The SBR received two streams of abattoir wastewater, namely the effluent from a full-scale anaerobic pond (75%) and the effluent from a lab-scale high-rate pre-fermentor (25%), both receiving raw abattoir wastewater as feed. The pond effluent contained approximately 250 mg N l(-1) total nitrogen and 40 mg P l(-1) of total phosphorus, but relatively low levels of soluble COD (around 500 mg l(-1)). The high-rate lab-scale pre-fermentor, operated at 37 degrees C and with a sludge retention time of 1 day, proved to be a cheap and effective method for providing supplementary volatile fatty acids allowing for high-degree of biological nutrient removal from abattoir wastewater.

  8. Monopolar Electro-Coagulation Process for Azo Dye C.I. Acid Red 18 Removal from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Ghasem Azarian

    2014-12-01

    Full Text Available The discharge of wastewaters containing an untreated dye results in aesthetic problems and an increase in gases solubility, which causes light transmission inhibition into water bodies. In spite of advantages of physicochemical and biological methods, these processes produce huge amounts of sludge, toxic by-products and require several oxidant chemicals. By contrast, electrochemical processes because of their high versatility, high efficiency and eco-friendly properties are more acceptable. In the present study, the removal of azo dye Acid Red 18 and chemical oxygen demand (COD from synthetic wastewater by monopolar (EC process was investigated and key parameters such as operating time, current density (CD, initial pH and energy, and electrode consumption were optimized. It was found that the process had a very good efficiency in the removal of both COD and color; for the iron electrode, the maximum amounts of color and COD removal were 99.5% and 59.0%, respectively. An operating time of 45 min, pH of 7 and CD of 1.2 mA/cm2 was selected as the optimized condition. The optimization of variables is extremely crucial as it results in a decrease in costs, energy and electrode consumption. Overall, the iron electrode used less energy than the aluminum electrode and was more acceptable for use in this process due to economical reasons. The findings of UV/vis spectra illustrated that the structures of this dye were removed by the process. In comparison with traditional methods such as aerobic and anaerobic systems, the EC process is a suitable alternative for the treatment of wastewaters containing dye pollutants.

  9. Potential Use of Atlantic Cod Trypsin in Biomedicine

    Directory of Open Access Journals (Sweden)

    Ágústa Gudmundsdóttir

    2013-01-01

    Full Text Available Surface proteins of viruses and bacteria used for cell attachment and invasion are candidates for degradation by proteases. Trypsin from Atlantic cod (Gadus morhua was previously demonstrated to have efficacy against influenza viruses in vitro and on skin. In this paper, cod trypsin is shown to be 3–12 times more effective in degrading large native proteins than its mesophilic analogue, bovine trypsin. This is in agreement with previous findings where cod trypsin was found to be the most active among twelve different proteases in cleaving various cytokines and pathological proteins. Furthermore, our results show that cod trypsin has high efficacy against herpes simplex virus type 1 (HSV-1 and the respiratory syncytial virus (RSV in vitro. The results on the antipathogenic properties of cod trypsin are important because rhinovirus, RSV, and influenza are the most predominant pathogenic viruses in upper respiratory tract infections. Results from a clinical study presented in this paper show that a specific formulation containing cod trypsin was preferred for wound healing over other methods used in the study. Apparently, the high digestive ability of the cold-adapted cod trypsin towards large native proteins plays a role in its efficacy against pathogens and its positive effects on wounds.

  10. Behavioral responses of Atlantic cod to sea temperature changes.

    Science.gov (United States)

    Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

    2015-05-01

    Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30-80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species.

  11. Analytical determination of Chemical Oxygen Demand in samples considered to be difficult to analyse: solid substrates and liquid samples with high suspended solid concentrations

    DEFF Research Database (Denmark)

    Raposo, Francisco; Fernández-Cegrí, V.; De la Rubia, M.A.

    Chemical oxygen demand (COD) is a critical analytical parameter in the field of waste and wastewater treatment processes, and more specifically in anaerobic digestion processes. However, little is known about the COD measurement quality of anaerobic digestion samples. Taking into account the lack...

  12. Quality improvement in determination of chemical oxygen demand in samples considered difficult to analyze, through participation in proficiency-testing schemes

    DEFF Research Database (Denmark)

    Raposo, Francisco; Fernández-Cegrí, V.; De la Rubia, M.A.

    2010-01-01

    Chemical oxygen demand (COD) is a critical analytical parameter in waste and wastewater treatment, more specifically in anaerobic digestion, although little is known about the quality of measuring COD of anaerobic digestion samples. Proficiency testing (PT) is a powerful tool that can be used...

  13. Optimization study for Pb(II) and COD sequestration by consortium of sulphate-reducing bacteria

    Science.gov (United States)

    Verma, Anamika; Bishnoi, Narsi R.; Gupta, Asha

    2017-09-01

    In this study, initial minimum inhibitory concentration (MIC) of Pb(II) ions was analysed to check optimum concentration of Pb(II) ions at which the growth of sulphate-reducing consortium (SRC) was found to be maximum. 80 ppm of Pb(II) ions was investigated as minimum inhibitory concentration for SRC. Influence of electron donors such as lactose, sucrose, glucose and sodium lactate was examined to investigate best carbon source for growth and activity of sulphate-reducing bacteria. Sodium lactate was found to be the prime carbon source for SRC. Later optimization of various parameters was executed using Box-Behnken design model of response surface methodology to explore the effectiveness of three independent operating variables, namely, pH (5.0-9.0), temperature (32-42 °C) and time (5.0-9.0 days), on dependent variables, i.e. protein content, precipitation of Pb(II) ions, and removal of COD by SRC biomass. Maximum removal of COD and Pb(II) was observed to be 91 and 98 %, respectively, at pH 7.0 and temperature 37 °C and incubation time 7 days. According to response surface analysis and analysis of variance, the experimental data were perfectly fitted to the quadratic model, and the interactive influence of pH, temperature and time on Pb(II) and COD removal was highly significant. A high regression coefficient between the variables and response ( r 2 = 0.9974) corroborate eminent evaluation of experimental data by second-order polynomial regression model. SEM and Fourier transform infrared analysis was performed to investigate morphology of PbS precipitates, sorption mechanism and involved functional groups in metal-free and metal-loaded biomass of SRC for Pb(II) binding.

  14. Optimization study for Pb(II) and COD sequestration by consortium of sulphate-reducing bacteria

    Science.gov (United States)

    Verma, Anamika; Bishnoi, Narsi R.; Gupta, Asha

    2016-04-01

    In this study, initial minimum inhibitory concentration (MIC) of Pb(II) ions was analysed to check optimum concentration of Pb(II) ions at which the growth of sulphate-reducing consortium (SRC) was found to be maximum. 80 ppm of Pb(II) ions was investigated as minimum inhibitory concentration for SRC. Influence of electron donors such as lactose, sucrose, glucose and sodium lactate was examined to investigate best carbon source for growth and activity of sulphate-reducing bacteria. Sodium lactate was found to be the prime carbon source for SRC. Later optimization of various parameters was executed using Box-Behnken design model of response surface methodology to explore the effectiveness of three independent operating variables, namely, pH (5.0-9.0), temperature (32-42 °C) and time (5.0-9.0 days), on dependent variables, i.e. protein content, precipitation of Pb(II) ions, and removal of COD by SRC biomass. Maximum removal of COD and Pb(II) was observed to be 91 and 98 %, respectively, at pH 7.0 and temperature 37 °C and incubation time 7 days. According to response surface analysis and analysis of variance, the experimental data were perfectly fitted to the quadratic model, and the interactive influence of pH, temperature and time on Pb(II) and COD removal was highly significant. A high regression coefficient between the variables and response (r 2 = 0.9974) corroborate eminent evaluation of experimental data by second-order polynomial regression model. SEM and Fourier transform infrared analysis was performed to investigate morphology of PbS precipitates, sorption mechanism and involved functional groups in metal-free and metal-loaded biomass of SRC for Pb(II) binding.

  15. Color removal of distillery wastewater by ozonation in the absence and presence of immobilized iron oxide catalyst.

    Science.gov (United States)

    Sreethawong, Thammanoon; Chavadej, Sumaeth

    2008-07-15

    Ozone is a strong oxidant, which can oxidize both biodegradable and non-biodegradable organics. The main objective of this study was to use iron oxide as a heterogeneous catalyst to enhance the ozone oxidation process. The wastewater used in this study was distillery wastewater, which was diluted 20 times before use. The diluted distillery wastewater was fed continuously in a downflow direction in an ozonation column. The iron oxide catalyst was coated on 10.3mm diameter alumina balls (5.5 m2/g specific surface area) by using Fe(NO3)3 as a precursor. The prepared catalyst was in the form of ferric oxide, and its loading was 0.07%. From the experimental results of both with and without the iron oxide catalyst, an increase in hydraulic retention time resulted in an increase in the treatment efficiencies of both chemical oxygen demand (COD) and color reduction, since the residence time of ozone increased. When the ozone mass flow rate increased, both COD and color reduction increased, resulting from an increase in the hydroxyl radical available in the system. The ozonation system with the iron oxide catalyst gave the highest efficiency in both COD and color removals because the hydroxyl free radical generated from the catalyst is more reactive than the ozone molecule itself.

  16. Efficiency and kinetic modeling of removal of nutrients and organic matter from a full-scale constructed wetland in Qasre-Shirin, Iran

    Directory of Open Access Journals (Sweden)

    Abdolmajid Gholizadeh

    2015-09-01

    Full Text Available Background: This study assessed the removal of organic material and nutrients from full-scale subsurface flow (SSF constructed wetlands (CWs followed by anaerobic stabilization ponds under environmental conditions. Methods: The effluents were distributed evenly in 12 reed beds. Samples were taken twice monthly for a total of 6 months from several points in the wetland. Biochemical oxygen demand (BOD, chemical oxygen demand (COD, total suspended solids (TSS, and nutrient removal from the system and the longitudinal effect of the reed beds for removal of pollutions were determined. A full-scale model of flow, BOD, and nutrients in SSF in the CWs is presented. Results: The flow rate and concentrations of parameters indicated that removal of organic matter and nutrients in the cold months decreased rather than in the hot months, as expected. The removal efficiency for BOD, COD, and TSS and the strongest biological interactions showed no uniform trends. The beds showed the highest removal rates in the first few meters of bed. The hybrid Monod-Plug flow regime and the Stover-Kincannon models showed the best fit for the kinetics of the processes. Umax in the Stover-Kincannon model was 3.64 mg/l.d for nitrogen and 0.24 mg/l.d for phosphorus. These values are very low, which indicates lower consumption and inefficiency of the system for removing nitrogen and phosphorus. Conclusion: It can be concluded that the SSF in CWs are able to treat average wastewater as effectively as common mechanical systems at lower cost.

  17. The COD Model: Simulating Workgroup Performance

    Science.gov (United States)

    Biggiero, Lucio; Sevi, Enrico

    Though the question of the determinants of workgroup performance is one of the most central in organization science, precise theoretical frameworks and formal demonstrations are still missing. In order to fill in this gap the COD agent-based simulation model is here presented and used to study the effects of task interdependence and bounded rationality on workgroup performance. The first relevant finding is an algorithmic demonstration of the ordering of interdependencies in terms of complexity, showing that the parallel mode is the most simplex, followed by the sequential and then by the reciprocal. This result is far from being new in organization science, but what is remarkable is that now it has the strength of an algorithmic demonstration instead of being based on the authoritativeness of some scholar or on some episodic empirical finding. The second important result is that the progressive introduction of realistic limits to agents' rationality dramatically reduces workgroup performance and addresses to a rather interesting result: when agents' rationality is severely bounded simple norms work better than complex norms. The third main finding is that when the complexity of interdependence is high, then the appropriate coordination mechanism is agents' direct and active collaboration, which means teamwork.

  18. Modeling of filtrate COD in submerged membrane bioreactor for oily wastewater treatment%SMBR处理含油废水出水COD数学模型

    Institute of Scientific and Technical Information of China (English)

    杜晓文; 王占生; 满春志; 李薇; 刘磊; 徐毅

    2012-01-01

    根据微生物生长动力学特征以及膜分离特征,建立恒通量下运行的一体式膜生物反应器系统出水COD数学模型,提出膜生物反应器处理效率的数学模型。以实验及模型为基础,分别对进水COD浓度控制在300、400、500 mg/L附近时经过反应器后COD的去除效率进行了比较。通过公式计算的数据和实验数据分析可得:COD去除率的公式计算值与实验结果比较吻合,相对偏差仅为0.0223,为膜系统有机物的去除效果估算提供了基础,可为该类工艺的参数选择与优化提供参考。%To predict the effluent quality in MBR processes, a mathematic model for removal efficiency in MBR processes was established, deriving from models standing for the chemical oxygen demand (COD) of the ef- fluent with constant membrane flux. The model was also based on the dynamics characteristics of microbial growth and membrane separation. The experiment was carried out in a lab-scale to treat oily wastewater in a submerged membrane bioreactor (SMBR). Thereby comparisons between experimental data and imputed value were investiga- ted at COD values of 300,400 and 500 mg/L. The results showed data good match of the COD removal efficiency between models and experiment, with a relative deviation of O. 0223, providing a foundation for estimating organics removing efficiency in membrane system and a recommendation for preferences and optimization of the processes.

  19. Farmed cod escapees and net-pen spawning left no clear genetic footprint in the local wild cod population

    Directory of Open Access Journals (Sweden)

    Rebekka Varne

    2015-11-01

    Full Text Available This study investigated a potential genetic introgression from farmed to wild cod Gadus morhua L. in the Trondheimsfjord, Norway. During the first 2 yr of operation of a cod farm in the inner part of the fjord, 2 large escape events and extensive pen spawning were reported. Analyses of 4 allozyme markers revealed no significant changes in allele frequencies between samples of wild cod before and after cod farming, although prominent allele frequency differences were demonstrated between wild and farmed samples. Analyses of 10 DNA markers showed a significant change between pre- and post-farming samples, due to contradictory allele frequency differences at Tch11, Pan I and Gmo132. Excluding those 3 markers due to null alleles (Tch11 and selection (Gmo132 and Pan I, the DNA markers paralleled the non-changed allele frequency signal from the allozymes. The topographies of the allozyme- and DNA-based dendrogram of the samples were congruent. Recaptures of tagged and released farmed cod indicated a seemingly random diffusion throughout the fjord and ended after approx. 6 mo. During an ongoing pen spawning, plankton net surveys sampling for cod eggs in the surroundings of the cod farm suggested the eggs originated from the farm. No larvae were present in the plankton samples. The apparent absence of introgression is explained relative to fitness and survival of pen-spawned larvae and adult escapees, and to a purging effect of the estuarine circulation of the Trondheimsfjord.

  20. Magnetic heterogeneous catalytic ozonation: a new removal method for phenol in industrial wastewater

    Science.gov (United States)

    2014-01-01

    In this study, a new strategy in catalytic ozonation removal method for degradation of phenol from industrial wastewater was investigated. Magnetic carbon nano composite as a novel catalyst was synthesized, characterized and then used in the catalytic ozonation process (COP) and compared with the single ozonation process (SOP). The influential parameters were all investigated. The results showed that the removal efficiency of phenol and COD (chemical oxygen demand) in COP (98.5%, 69.8%) was higher than those of SOP (78.7%, 50.5%) and the highest catalytic potential was achieved at optimal neutral pH. First order modeling demonstrated that the reactions were dependent on the concentration of catalyst, with kinetic constants varying from 0.023 1/min (catalyst = 0 g/L) to 0.071 1/min (catalyst = 4 g/L), whereby the optimum dosage of catalyst was found to be 2 g/L. Furthermore, the catalytic properties of the catalyst remained almost unchanged after 5-time reuse. The results regarding the biodegradability of the effluent showed that a 5-min reaction time in COP reduced the concentrations of phenol and COD to the acceptable levels for the efficient post-treatment in the SBR in a 4-h cycle period. Finally, this combined system is proven to be a technically effective method for treating phenolic contaminants. PMID:24572145

  1. Removal of sulfamethoxazole and diclofenac from water: strategies involving O3 and H2O2.

    Science.gov (United States)

    Gomes, Daniela S; Gando-Ferreira, Licínio M; Quinta-Ferreira, Rosa M; Martins, Rui C

    2017-06-08

    Diclofenac (DCF) and Sulfamethoxazole (SMX) are two of the most frequently detected pharmaceutical compounds in water and are hardly removed by biological treatment systems. The presence of H2O2 was investigated in the ozonation of these two compounds. Experiments were carried out with both using distilled water and secondary effluent from a municipal wastewater treatment plant spiked with pharmaceuticals. Chemical oxygen demand (COD) abatement rate improved when H2O2 was added at the beginning of the ozonation process and when the ozone inlet concentration increased, attaining a maximum value of 91% and simultaneously a lower ozone waste for a H2O2 initial concentration of 5 mM and an ozone inlet concentration of 20 g Nm(-3). For these operation conditions, the water matrix has no significant impact on SMX and DCF removal, which were totally degraded in 45 and 60 min, respectively. Nevertheless, lower COD degradation and ozone usage were obtained when the secondary effluent was used. Inorganic ions such as chloride, sulphate and nitrate and short-chain organic compounds were detected as by-products of the SMX and DCF oxidation. Vibrio fischeri luminescence inhibition tests revealed that simultaneous use of ozone and H2O2 reduced acute toxicity.

  2. PREDICTION OF BOD AND COD OF A REFINERY WASTEWATER USING MULTILAYER ARTIFICIAL NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Eldon Raj Rene

    2008-06-01

    Full Text Available In the recent past, artificial neural networks (ANNs have shown the ability to learn and capture non-linear static or dynamic behaviour among variables based on the given set of data. Since the knowledge of internal procedure is not necessary, the modelling can take place with minimum previous knowledge about the process through proper training of the network. In the present study, 12 ANN based models were proposed to predict the Biochemical Oxygen Demand (BOD5 and Chemical Oxygen Demand (COD concentrations of wastewater generated from the effluent treatment plant of a petrochemical industry. By employing the standard back error propagation (BEP algorithm, the network was trained with 103 data points for water quality indices such as Total Suspended Solids (TSS, Total Dissolved Solids (TDS, Phenol concentration, Ammoniacal Nitrogen (AMN, Total Organic Carbon (TOC and Kjeldahl’s Nitrogen (KJN to predict BOD and COD. After appropriate training, the network was tested with a separate test data and the best model was chosen based on the sum square error (training and percentage average relative error (% ARE for testing. The results from this study reveal that ANNs can be accurate and efficacious in predicting unknown concentrations of water quality parameters through its versatile training process.

  3. Enhanced nitrogen removal in single-chamber microbial fuel cells with increased gas diffusion areas

    KAUST Repository

    Yan, Hengjing

    2012-11-23

    Single-chamber microbial fuel cells (MFCs) with nitrifiers pre-enriched at the air cathodes have previously been demonstrated as a passive strategy for integrating nitrogen removal into current-generating bioelectrochemical systems. To further define system design parameters for this strategy, we investigated in this study the effects of oxygen diffusion area and COD/N ratio in continuous-flow reactors. Doubling the gas diffusion area by adding an additional air cathode or a diffusion cloth significantly increased the ammonia and COD removal rates (by up to 115% and 39%), ammonia removal efficiency (by up to 134%), the cell voltage and cathode potentials, and the power densities (by a factor of approximately 2). When the COD/N ratio was lowered from 13 to 3, we found up to 244% higher ammonia removal rate but at least 19% lower ammonia removal efficiency. An increase of COD removal rate by up to 27% was also found when the COD/N ratio was lowered from 11 to 3. The Coulombic efficiency was not affected by the additional air cathode, but decreased by an average of 11% with the addition of a diffusion cloth. Ammonia removal by assimilation was also estimated to understand the ammonia removal mechanism in these systems. These results showed that the doubling of gas diffusion area enhanced N and COD removal rates without compromising electrochemical performance. © 2012 Wiley Periodicals, Inc.

  4. Adsorption photobioreactor as a co-treatment system for ammonium and phosphate removal by the response surface method.

    Science.gov (United States)

    Ganjian, Etesam; Peyravi, Majid; Asqar Qoreyshi, Ali; Jahanshahi, Mohsen; Shokuhi Rad, Ali

    2017-07-01

    The co-treatment system of photosynthetic microalgae Chlorella vulgaris and adsorption was investigated as a possible combination of symbiotic mixed culture for the simultaneous removal of nutrients (ammonium and phosphate) and organic contaminants. In this study, response surface methodology for experimental design and optimization was used. For experiment operation, two factorial designs containing five chemical oxygen demand influent (CODin) concentrations (100, 200, 400, 600 and 700 mg l(-1)) and hydraulic retention times (0.63, 1, 1.75, 2.5 and 2.88 d) were applied. The co-treatment system performed successfully in removing both nutrients (nitrogen and phosphate) and COD, showing around 88%, 75% and 48% removal for the maximum level, respectively. The adsorption-photobioreactor (APBR) displayed superior performance of the microalgae growth rate compared to the photobioreactor. Also, the adsorption capacity (the uptake of COD) has been analysed with the first-order equation. The results showed that the experimental data of the APBR fit well with the model.

  5. Research of Bentonite Modification Used for Treatment the COD in Landfill Leachate%用于处理垃圾渗滤液中 COD 的膨润土改性研究

    Institute of Scientific and Technical Information of China (English)

    肖筱瑜

    2014-01-01

    In order to treatment the COD in landfill leachate , the modified method and removal efficiency of bentonite modified by PAC were researched.The result showed that removal efficiency of bentonite was improved after modified , and the modified time and quantity of modifier solution had a certain influence on the COD removal effect .After treated by modified bentonite , the COD in landfill leachate still can not meet contented I -class criteria specified in Integrated Wastewater Discharge Standard ( GB 8978-1996).%为去除应急池中垃圾渗滤液中的COD,研究了用PAC改性膨润土的方法及效果,结果表明:改性可提高改性膨润土去除垃圾渗滤液中COD的能力,改性剂用量和改性时间对改性膨润土的除COD效率影响较大。但制备的PAC改性膨润土用于处理垃圾渗滤液的处理,其出水水质均不能满足污水综合排放标准(GB8978-1996)的一级标准限值要求(COD≤60 mg/L)。

  6. Cod Fractions In Mechanical-Biological Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Płuciennik-Koropczuk Ewelina

    2017-03-01

    Full Text Available The paper presents results of studies concerning the designation of COD fraction in the raw, mechanically treated and biologically treated wastewater. The test object was a wastewater treatment plant with the output of over 20,000 PE. The results were compared with data received in the ASM models. During investigation following fractions of COD were determined: dissolved non-biodegradable SI, dissolved easily biodegradable SS, in organic suspension slowly degradable XS and in organic suspension non-biodegradable XI. Methodology for determining the COD fraction was based on the guidelines ATV-A 131. The real percentage of each fraction in total COD in raw wastewater are different from data received in ASM models.

  7. N2O emissions from an intermittently aerated semi-aerobic aged refuse bioreactor: Combined effect of COD and NH4(+)-N in influent leachate.

    Science.gov (United States)

    Li, Weihua; Sun, Yingjie; Bian, Rongxing; Wang, Huawei; Zhang, Dalei

    2017-08-12

    The carbon-nitrogen ratio (COD/NH4(+)-N) is an important factor affecting nitrification and denitrification in wastewater treatment; this factor also influences nitrous oxide (N2O) emissions. This study investigated two simulated intermittently aerated semi-aerobic aged refuse bioreactors (SAARB) filled with 8-year old aged refuse (AR). The research analyzed how differences in and the combination of influent COD and NH4(+)-N impact N2O emissions in leachate treatment. Experimental results showed that N2O emissions increased as the influent COD/NH4(+)-N decreased. The influent COD had a greater effect on N2O emissions than NH4(+)-N at the same influent ratios of COD/NH4(+)-N (2.7 and 8.0, respectively). The maximum N2O emission accounted for 8.82±2.65% of the total nitrogen removed from the influent leachate; the maximum level occurred when the COD was 2000mg/L. An analysis of differences in influent carbon sources at the same COD/NH4(+)-N ratios concluded that the availability of biodegradable carbon substrates (i.e. glucose) is an important factor affecting N2O emissions. At a low influent COD/NH4(+)-N ratio (2.7), the N2O conversion rate was greater when there were more biodegradable carbon substrates. Although the SAARB included the N2O generation and reduction processes, N2O reduction mainly occurred later in the process, after leachate recirculation. The maximum N2O emission rate occurred in the first hour of single-period (24h) experiments, as leachate contacted the surface AR. In practical SAARB applications, N2O emissions may be reduced by measures such as reducing the initial recirculation loading of NH4(+)-N substrates, adding a later supplement of biodegradable carbon substrates, and/or prolonging hydraulic retention time (HRT) of influent leachate. Copyright © 2017. Published by Elsevier Ltd.

  8. Experimental investigation of the external nitrification biological nutrient removal activated sludge (ENBNRAS) system.

    Science.gov (United States)

    Hu, Zhi-Rong; Sötemann, S; Moodley, R; Wentzel, M C; Ekama, G A

    2003-08-01

    A systematic lab-scale experimental investigation is reported for the external nitrification (EN) biological nutrient removal (BNR) activated sludge (ENBNRAS) system, which is a combined fixed and suspended medium system. The ENBNRAS system was proposed to intensify the treatment capacity of BNR-activated sludge (BNRAS) systems by addressing two difficulties often encountered in practice: (a) the long sludge age for nitrification requirement; and (b) sludge bulking. In the ENBNRAS system, nitrification is transferred from the aerobic reactor in the suspended medium activated sludge system to a fixed medium nitrification system. Thus, the sludge age of the suspended medium activated sludge system can be reduced from 20 to 25 days to 8 to 10 days, resulting in a decrease in reactor volume per ML wastewater treated of about 30%. Furthermore, the aerobic mass fraction can also be reduced from 50% to 60% to 55% (if the anaerobic mass fraction is 15%), and thus complete denitrification in the anoxic reactors becomes possible. Research indicates that both the short sludge age and complete denitrification could ameliorate anoxic aerobic (AA) or low food/microorganism (F/M) ratio filamentous bulking, and hence reduce the surface area of secondary settling tanks or increase the treatment capacity of existing systems. The lab-scale experimental investigations indicate that the ENBNRAS system can obtain: (i) very good chemical oxygen demand (COD) removal, even with an aerobic mass fraction as low as 20%; (ii) high nitrogen removal, even for a wastewater with a high total kjeldahl nitrogen (TKN)/COD ratio, up to 0.14; (iii) adequate settling sludge (diluted sludge volume index [DSVI] <100 mL/g); and (iv) a significant reduction in oxygen demand.

  9. Salted and dried Cod preserved by vacuum and modified atmosphere

    Directory of Open Access Journals (Sweden)

    Maria José Rodrigues

    2014-06-01

    Full Text Available Temperatures higher than 20ºC can boost the growth, on the salted and dried cod surface, of bacteria that present a red pigment (Rodrigues et al., 2003; Rodrigues et al., 2005. These organisms, besides the change of the food product appearance, also cause an unpleasant flavor and the product is rejected by the consumers, although does not cause any health concern. Currently, the export of salted and dried cod, to Africa, has increased and a great amount of product is rejected due to the high environmental temperature and the lack of a proper cold chain storage infrastructure. Vacuum packaging, and modified atmosphere packaging have been used for fresh and cooked seafood preservation, but, as far as the authors know, were never used to preserve salted and dried fish. In the present study it was observed the effect of vacuum packaging, packaging with 80%N2:20%CO2 and finally the addition of sodium metabisulfite on the salted and dried cod stored under temperature abuse (15ºC, 25ºC and 35ºC. Accordingly, packaging under vacum and, specially, packaging with 80%N2:20%CO2 successfuly increased the shellife of salted and dried cod . The addition of sodium metabisulfite has increased the shelflife of salted and dried cod preserved at 15ºC, but not of salted and dried cod preserved at 25ºC and 35ºC.

  10. Effects of injection of acetic acid and propionic acid for total phosphorus removal at high temperature in enhanced biological phosphorus removal process.

    Science.gov (United States)

    Ki, C Y; Kwon, K H; Kim, S W; Min, K S; Lee, T U; Park, D J

    2014-01-01

    In summer, wastewater treatment plant total phosphorus (TP) removal efficiency is low in South Korea. The reason is because of high temperatures or significant fluctuation of inflow characteristics caused by frequent rainfall. Hence, this study tried to raise TP removal efficiency by injecting fixed external carbon sources in real sewage. Polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) compete to occupy microorganisms at high temperature. Propionate is known to restrain GAOs. Thus, acetate and propionate were chosen as the external carbon source in this study to find out the suitable volume and ratio of carbon source which ensured the dominance of PAOs. An external carbon source was supplied in the anaerobic reactor of the biological phosphorus removal process at high temperature (above 25 °C). TP removal efficiency was improved by injecting an external carbon source compared to that without an external carbon source. Also, it remained relatively stable when injecting an external carbon source, despite the variation in temperature. TP removal efficiency was the highest when injecting acetate and propionate in the proportion of 2:1 (total concentration as chemical oxygen demand (COD) is 12 mg/L in influent).

  11. Remediation of Urban River Water by Pontederia Cordata Combined with Artificial Aeration: Organic Matter and Nutrients Removal and Root-Adhered Bacterial Communities.

    Science.gov (United States)

    Gu, Dungang; Xu, Huan; He, Yan; Zhao, Feng; Huang, Minsheng

    2015-01-01

    Macrophyte combined with artificial aeration is a promising in situ remediation approach for urban rivers polluted with nutrients and organic matter. However, seasonal variations and aeration effects on phytoremediation performance and root-adhered microbial communities are still unclear. In this study, Pontederia cordata was used to treat polluted urban river water under various aeration intensities. Results showed that the highest removal efficiencies of chemical oxygen demand (COD(Cr)) and total nitrogen (TN) were attained under aeration of 30 L min(-1) in spring and summer and 15 L min(-1) in autumn, while total phosphorus (TP) removal reached maximum with aeration of 15 L min(-1) in all seasons. Moderate aeration was beneficial for increasing the diversity of root-adhered bacteria communities, and the shift of bacterial community structure was more pronounced in spring and autumn with varying aeration intensity. The dual effect, i.e. turbulence and dissolved oxygen (DO), of aeration on the removal of COD(Cr) and TN prevailed over the individual effect of DO, while DO was the most influential factor for TP removal and the root-adhered bacterial community diversity. P. cordata combined with 15 L min(-1) aeration was deemed to be the best condition tested in this study.

  12. Internal carbon source from sludge pretreated by microwave-H2O2 for nutrient removal in A2/O-membrane bioreactors.

    Science.gov (United States)

    Xu, Rongle; Zhang, Qing; Tong, Juan; Wei, Yuansong; Fan, Yaobo

    2015-01-01

    To improve the nutrient removal, the feasibility was studied for the organics released from sludge pretreated by microwave-H2O2 process (MHP) to be used as internal carbon source in two A2/O-membrane bioreactors (MBRs). The experiments were conducted for the nutrient removal and the membrane fouling. The results showed that the removal efficiencies of TN and TP were improved by 11% and 28.34%, respectively, as C/N ratio was adjusted to 8 by adding the internal carbon source, and the ratio of soluble chemical oxygen demand (sCOD) consumed easily for denitrification was about 46% of the total sCOD in the internal carbon source. The addition of the internal carbon sources did not lead to severe membrane fouling in the experimental A2/O-MBR. It is implied that the organics released from sludge pretreated by MHP could be used as the internal carbon source to enhance the nutrient removal in A2/O-MBRs.

  13. Enhanced long-term ammonium removal and its ranked contribution of microbial genes associated with nitrogen cycling in a lab-scale multimedia biofilter.

    Science.gov (United States)

    Wang, Honglei; Ji, Guodong; Bai, Xueyuan

    2015-11-01

    The multimedia biofilter achieved high and stable removal efficiencies for chemical oxygen demand (COD, 62-98%) and NH4(+) (68-98%) without costly aeration. Results revealed that lower CL (less than 13.9gCOD/m(3)d) and ACL (less than 2.8gNH4(+)-N/m(3)d) or a C/N ratio exceeding five was required to reduce NO3(-)-N accumulation and NO/N2O emission. Integrated analyses indicated that the coupling of simultaneous nitrification, anammox and denitrification processes (SNAD) were the primary reason accounted for the enhanced NH4(+)-N treatment performance. NH4(+)-N removal pathways can be ranked as follows: nitrification (amoA, archaeal) (54.6%)>partial denitrification (nirS, nirK) and anammox (37.8%)>anammox and partial denitrification (narG, napA) (12.6%). Specifically, NH4(+)-N removal was significantly inhibited by NO2(-)-N accumulation in the system (-21.6% inhibition). Results from stepwise regression analysis suggested that the NH4(+) removal rate was collectively controlled by amoA, archaeal, anammox, nirS, nirK, narG and napA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Thermal niche of Atlantic cod Gadus morhua: limits, tolerance and optima

    DEFF Research Database (Denmark)

    Righton, David A.; Andersen, Ken Haste; Neat, Francis

    2010-01-01

    in those cod with a mean thermal history of between 8 and 10°C. Our direct observations of habitat occupation suggest that adult cod will be able to tolerate warming seas, but that climate change will affect cod populations at earlier life-history stages as well as exerting effects on cod prey species....

  15. The enzyme profiles in the connective tissue attaching pin bones to the surrounding tissue is specific in farmed salmon (Salmo salar) and cod (Gadus morhua L.).

    Science.gov (United States)

    Vuong, Tram T; Rønning, Sissel B; Kolset, Svein O; Pedersen, Mona E

    2017-02-01

    Post mortem storage is a necessary process for removal of pin bones without destruction of fillets, thereby avoiding volume and economic loss. However, the enzymes involved in loosening pin bones during storage have not been studied to a great extent. In this study, the activities and localization of MMPs in the connective tissue (CT) of pin bones dissected from fillet of salmon and cod were investigated. Interestingly, the enzyme activity profile in these two species was different during post mortem storage of fish fillets. Adding MMP inhibitor (GM6001) and serine protease inhibitor (Pefabloc) revealed different effects in the two species, suggesting different regulations in salmon and cod. In situ zymography with the same inhibitors verified MMP and serine protease activity in CT close to pin bone at early post mortem (6 h) in salmon. However, MMP inhibition was not evident in cod in this area at that time point. Immunohistochemistry further revealed MMP9 and MMP13 were located more to the outer rim of CT, facing the pin bone and adipose tissue, while MMP7 was more randomly distributed within CT in salmon. In contrast, all these three MMPs were randomly distributed in CT in cod. In summary, our study reveals different MMP enzyme profiles in salmon and cod in the pin bone area, influenced by serine proteases, and suggests that MMPs and serine proteases must be taken in consideration when studying the conditions for early pin bone removal.

  16. Biogas-pH automation control strategy for optimizing organic loading rate of anaerobic membrane bioreactor treating high COD wastewater.

    Science.gov (United States)

    Yu, Dawei; Liu, Jibao; Sui, Qianwen; Wei, Yuansong

    2016-03-01

    Control of organic loading rate (OLR) is essential for anaerobic digestion treating high COD wastewater, which would cause operation failure by overload or less efficiency by underload. A novel biogas-pH automation control strategy using the combined gas-liquor phase monitoring was developed for an anaerobic membrane bioreactor (AnMBR) treating high COD (27.53 g·L(-1)) starch wastewater. The biogas-pH strategy was proceeded with threshold between biogas production rate >98 Nml·h(-1) preventing overload and pH>7.4 preventing underload, which were determined by methane production kinetics and pH titration of methanogenesis slurry, respectively. The OLR and the effluent COD were doubled as 11.81 kgCOD·kgVSS(-1)·d(-1) and halved as 253.4 mg·L(-1), respectively, comparing with a constant OLR control strategy. Meanwhile COD removal rate, biogas yield and methane concentration were synchronously improved to 99.1%, 312 Nml·gCODin(-1) and 74%, respectively. Using the biogas-pH strategy, AnMBR formed a "pH self-regulation ternary buffer system" which seizes carbon dioxide and hence provides sufficient buffering capacity.

  17. Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

    Institute of Scientific and Technical Information of China (English)

    XU Qiu-jin; NIAN Yue-gang; JIN Xiang-can; YAN Chang-zhou; LIU Jin; Jiang Gao-ming

    2007-01-01

    Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. verticillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.

  18. Environmental capacity of chemical oxygen demand in the Bohai Sea: modeling and calculation

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xixi; WANG Xiulin; SHI Xiaoyong; LI Keqiang; DING Dongsheng

    2011-01-01

    A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity (EC) and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77×104t/a, 116×l04t/a, 154×l04t/a and 193×104t/a, respectively. The Huanghe (Yellow) River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River (11.5%), and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater.

  19. Long-term effects of antibiotics on the elimination of chemical oxygen demand, nitrification, and viable bacteria in laboratory-scale wastewater treatment plants.

    Science.gov (United States)

    Schmidt, Susan; Winter, Josef; Gallert, Claudia

    2012-10-01

    Antibiotics and other pharmaceuticals are contaminants of the environment because of their widespread use and incomplete removal by microorganisms during wastewater treatment. The influence of a mixture of ciprofloxacin (CIP), gentamicin (GM), sulfamethoxazole (SMZ)/trimethoprim (TMP), and vancomycin (VA), up to a final concentration of 40 mg/L, on the elimination of chemical oxygen demand (COD), nitrification, and survival of bacteria, as well as the elimination of the antibiotics, was assessed in a long-term study in laboratory treatment plants (LTPs). In the presence of 30 mg/L antibiotics, nitrification of artificial sewage by activated sludge ended at nitrite. Nitrate formation was almost completely inhibited. No nitrification at all was possible in the presence of 40 mg/L antibiotics. The nitrifiers were more sensitive to antibiotics than heterotrophic bacteria. COD elimination in antibiotic-stressed LTPs was not influenced by ≤20 mg/L antibiotics. Addition of 30 mg/L antibiotic mixture decreased COD removal efficiency for a period, but the LTPs recovered. Similar results were obtained with 40 mg/L antibiotic mixture. The total viable count of bacteria was not affected negatively by the antibiotics. It ranged from 2.2 × 10(6) to 8.2 × 10(6) colony-forming units per milliliter (CFU/mL) compared with the control at 1.4 × 10(6)-6.3 × 10(6) CFU/mL. Elimination of the four antibiotics during phases of 2.4-30 mg/L from the liquid was high for GM (70-90 %), much lower for VA, TMP, and CIP (0-50 %), and highly fluctuating for SMZ (0-95 %). The antibiotics were mainly adsorbed to the sludge and not biodegraded.

  20. Optimized aeration strategies for nitrogen and phosphorus removal with aerobic granular sludge.

    Science.gov (United States)

    Lochmatter, Samuel; Gonzalez-Gil, Graciela; Holliger, Christof

    2013-10-15

    Biological wastewater treatment by aerobic granular sludge biofilms offers the possibility to combine carbon (COD), nitrogen (N) and phosphorus (P) removal in a single reactor. Since denitrification can be affected by suboptimal dissolved oxygen concentrations (DO) and limited availability of COD, different aeration strategies and COD loads were tested to improve N- and P-removal in granular sludge systems. Aeration strategies promoting alternating nitrification and denitrification (AND) were studied to improve reactor efficiencies in comparison with more classical simultaneous nitrification-denitrification (SND) strategies. With nutrient loading rates of 1.6 gCOD L(-1) d(-1), 0.2 gN L(-1) d(-1), and 0.08 gP L(-1) d(-1), and SND aeration strategies, N-removal was limited to 62.3 ± 3.4%. Higher COD loads markedly improved N-removal showing that denitrification was limited by COD. AND strategies were more efficient than SND strategies. Alternating high and low DO phases during the aeration phase increased N-removal to 71.2 ± 5.6% with a COD loading rate of 1.6 gCOD L(-1) d(-1). Periods of low DO were presumably favorable to denitrifying P-removal saving COD necessary for heterotrophic N-removal. Intermittent aeration with anoxic periods without mixing between the aeration pulses was even more favorable to N-removal, resulting in 78.3 ± 2.9% N-removal with the lowest COD loading rate tested. P-removal was under all tested conditions between 88 and 98%, and was negatively correlated with the concentration of nitrite and nitrate in the effluent (r = -0.74, p < 0.01). With low COD loading rates, important emissions of undesired N2O gas were observed and a total of 7-9% of N left the reactor as N2O. However, N2O emissions significantly decreased with higher COD loads under AND conditions.

  1. Shell plans big COD/sub 2/U miscible drive

    Energy Technology Data Exchange (ETDEWEB)

    1966-04-18

    Shell Oil Co. is seeking approval from the Texas Railroad Commission for the first field test using COD2U as a miscible slug. The test would take place in the Crossett Field, Crane and Upton Counties, 5 miles West of McCamey. Plan calls for injecting a large slug of COD2U in the Devonian reservoir, and following this with water to maintain reservoir pressure and serve as a sweeping medium. If the method works as anticipated, Shell says it will recover 32.8 million bbl of 44$-gravity crude--or 63.8% of the oil originally in place. Residue gas in now being injected in the field's North Cross unit. Widespread application of the process, if it works as hoped, seems unlikely because of the difficulty and cost of transporting COD2U where it is needed. However, ample supplies of COD2U are available in West Texas. There are at least 3 sources of COD2U in the vicinity. Norhtern Natural Gas Co. is venting some 20 MMcfd at is gas processing plant at Puckett field in Pecos County. Not far away is Hunt Oil Co.'s 57 Elsinore Ranch well, a dry hole that tested COD2U at the rate of 19 MMcfd. The most likely source of COD2U for Shell's proposed test is El Paso Natural Gas Co.'s processing plant at Brown-Basset Field in Terrell County, where gas is now being vented to the atmosphere at the rate of 40 MMscfd.

  2. Removal of pharmaceuticals in biologically treated wastewater by chlorine dioxide or peracetic acid.

    Science.gov (United States)

    Hey, G; Ledin, A; Jansen, J la Cour; Andersen, H R

    2012-01-01

    Removal of six active pharmaceutical ingredients in wastewater was investigated using chlorine dioxide (ClO2) or peracetic acid (PAA) as chemical oxidants. Four non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, diclofenac and mefenamic acid) and two lipid-regulating agents (gemfibrozil and clofibric acid, a metabolite of clofibrate) were used as target substances at 40 microg/L initial concentration. Three different wastewaters types originating from two wastewater treatment plants (WWTPs) were used. One wastewater was collected after extended nitrogen removal in activated sludge, one after treatment with high-loaded activated sludge without nitrification, and one from the final effluent from the same plant where nitrogen removal was made in trickling filters for nitrification and moving-bed biofilm reactors for denitrification following the high-loaded plant. Of the six investigated compounds, only clofibric acid and ibuprofen were not removed when treated with ClO2 up to 20 mg/L. With increasing PAA dose up to 50 mg/L, significant removal of most of the pharmaceuticals was observed except for the wastewater with the highest chemical oxygen demand (COD). This indicates that chemical oxidation with ClO2 could be used for tertiary treatment at WWTPs for active pharmaceutical ingredients, whereas PAA was not sufficiently efficient.

  3. Removal of Heavy Metals from Liquid Laboratory Waste Using Precipitation and Adsorption Methods

    Directory of Open Access Journals (Sweden)

    Nastiti Siswi Indrasti

    2010-04-01

    Full Text Available Liquid laboratory waste (such as residue of Chemical Oxygen Demand/COD analysis contains high concentration of heavy metals (mercury/Hg, silver/Ag and chrome/Cr and has a high potential to pollute the environment. The liquid waste generated by laboratories is generally in small quantity, but it is extremely toxic. It is urgently in need to find out an appropriate method to reduce the problems according to the liquid waste characteristics. In this research work, precipitation and adsorption methods were evaluated to remove Hg, Ag and Cr from liquid laboratory waste, covering determination of optimum process conditions, levels of removal and achievable treated waste quality. Results showed that a Cr removal of 97% was obtained by pH 10, and Hg and Ag removals of 97-99% were reached by pH 12. Although heavy metals removals using precipitation was very significant, but the concentration of heavy metals in the treated waste was still high (0.73-2.62 mg/L and need for further treatment. Applying activated carbon adsorption for further treatment of the effluent reduced dissolved heavy metals to 0-0.05 mg/L, depending on the type of heavy metals as well as the type and dosing of activated carbon.

  4. Ammonium nitrogen removal in batch cultures treating digested piggery wastewater with microalgae Oedogonium sp.

    Science.gov (United States)

    Wang, Haiping; Hu, Zhiquan; Xiao, Bo; Cheng, Qunpeng; Li, Fanghua

    2013-01-01

    Due to the nutrient characteristics of the high concentration of available ammonium in digested piggery wastewater (DPW), microalgae can be used to treat DPW before its final discharge. Four green microalgae (Hydrodictyaceae reticulatum Lag, Scenedesmus obliquus, Oedogonium sp. and Chlorella pyrenoidosa) and three blue-green algae (Anabaena flos-aquae, Oscillatoria amoena Gom and Spirulina platensis) were used to remove the nutrients (N, P, C), especially ammonium nitrogen (NH4(+)-N), from diluted DPW with 300 mg/L algae density in batch tests. The microalgae with the best NH4(+)-N nutrient removal was then selected for further optimization of the variables to improve NH4(+)-N removal efficiency using a central composite design (CCD) experiment. Taking into account the nutrient removal efficiency, Oedogonium sp. showed the best performance (reduction of 95.9% NH4(+)-N, 92.9% total phosphorus (TP) and 62.5% chemical oxygen demand (COD)) based on the results of the batch tests. The CCD results suggested that the optimal values of variables were initial Oedogonium sp. density of 399.2 mg/L and DPW diluted by 16.3, while the predicted value of NH4(+)-N removal efficiency obtained was 97.0%.

  5. Seasonal Variation of Nutrient Removal in a Full-Scale Artificial Aerated Hybrid Constructed Wetland

    Directory of Open Access Journals (Sweden)

    Jun Zhai

    2016-11-01

    Full Text Available To improve nutrient removal, a full-scale hybrid constructed wetland (CW consisting of pre-treatment units, vertical-baffled flow wetlands (VBFWs, and horizontal subsurface flow wetlands (HSFWs was installed in August 2014 to treat sewage wastewater. Artificial aeration (AA was applied continuously in the VBFW stage to improve the aerobic condition in the hybrid CW. Water samples were collected and analyzed twice a month between the period of August 2015 and July 2016. The results suggest that this new hybrid CW can achieve a satisfactory reduction of chemical oxygen demand (COD, ammonium nitrogen (NH4+-N, total nitrogen (TN, and total phosphorus (TP with average removal rates of 85% ± 10% (35% ± 19 g/m2 per day, 76% ± 18% (7% ± 2 g/m2 per day, 65% ± 13% (8% ± 2 g/m2 per day, and 65% ± 21% (1 g/m2 per day, respectively. AA significantly improved the aerobic condition throughout the experimental period, and the positive influence of AA on nitrogen removal was found to be higher during summer that during winter. A significant positive correlation between water temperature and nutrient removal (p < 0.01 was observed in the system. Overall, this study demonstrates the application of AA in a full-scale hybrid CW with satisfactory nutrient removal rates. The hybrid CW system with artificial aeration can serve as a reference for future applications areas where land availability is limited.

  6. Nitrogen and carbon removal efficiency of a polyvinyl alcohol gel based moving bed biofilm reactor system.

    Science.gov (United States)

    Gani, Khalid Muzamil; Singh, Jasdeep; Singh, Nitin Kumar; Ali, Muntjeer; Rose, Vipin; Kazmi, A A

    2016-01-01

    In this study, the effectiveness of polyvinyl alcohol (PVA) gel beads in treating domestic wastewater was investigated: a moving bed biofilm reactor (MBBR) configuration (oxic-anoxic and oxic) with 10% filling fraction of biomass carriers was operated in a continuously fed regime at temperatures of 25, 20, 15 and 6 °C with hydraulic retention times (HRTs) of 32 h, 18 h, 12 h and 9 h, respectively. Influent loadings were in the range of 0.22-1.22 kg N m(-3) d(-1) (total nitrogen (TN)), 1.48-7.82 kg chemical oxygen demand (COD) m(-3) d(-1) (organic) and 0.12-0.89 kg NH4(+)-N m(-3)d(-1) (ammonia nitrogen). MBBR performance resulted in the maximum TN removal rate of 1.22 kg N m(-3) d(-1) when the temperature and HRT were 6 °C and 9 h, respectively. The carbon removal rate at this temperature and HRT was 6.82 kg COD m(-3) d(-1). Ammonium removal rates ranged from 0.13 to 0.75 kg NH4(+)-N m(-3) d(-1) during the study. Total phosphorus and suspended solid removal efficiency ranged from 84 to 98% and 85 to 94% at an influent concentration of 3.3-7.1 mg/L and 74-356 mg/L, respectively. The sludge wasted from the MBBR exhibited light weight features characterized by sludge volume index value of 185 mL/g. Experimental data obtained can be useful in further developing the concept of PVA gel based wastewater treatment systems.

  7. Implications of stock recovery for a neighbouring management unit: experience from the Baltic cod

    DEFF Research Database (Denmark)

    Eero, Margit; Hansen, Jakob Hemmer; Hüssy, Karin

    2014-01-01

    Cod in the Baltic Sea is assessed and managed as two separate stocks, i.e. eastern and western Baltic cod. The eastern Baltic cod has recently started to recover after several decades of severe depletion. In the present study, we suggest that the recovery of the eastern Baltic cod population has...... also substantially increased cod abundance in a specific area of the adjacent western Baltic management unit. This is investigated through long time-series of spatially resolved stock assessment data supplemented by genetic analyses of origin of the cod currently found in the transition area between...... the two populations. Due to immigrating cod from the east, there are currently large spatial differences in cod abundance and mean weight in the western Baltic management unit that raise new management concerns. First, the high abundance of cod of eastern origin found in the western Baltic management unit...

  8. Removal of Penicillin G by combination of sonolysis and Photocatalytic (sonophotocatalytic) process from aqueous solution: process optimization using RSM (Response Surface Methodology)

    Science.gov (United States)

    Almasi, Ali; Dargahi, Abdollah; Mohamadi, Mitra; Biglari, Hamed; Amirian, Farhad; Raei, Mehdi

    2016-01-01

    Introduction Penicillin G (PG) is used in a variety of infectious diseases, extensively. Generally, when antibiotics are introduced into the food chain, they pose a threat to the environment and can risk health outcomes. The aim of the present study was the removal of Penicillin G from an aqueous solution through an integrated system of UV/ZnO and UV/WO3 with Ultrasound pretreatment. Methods In this descriptive-analytical work dealing with the removal of Penicillin G from an aqueous solution, four significant variables, contact time (60–120 min), Penicillin G concentration (50–150 mg/L), ZnO dose (200–400 mg/L), and WO3 dose (100–200 mg/L) were investigated. Experiments were performed in a Pyrex reactor (batch, 1 Lit) with an artificial UV 100-Watt medium pressure mercury lamp, coupled with ultrasound (100 W, 40 KHz) for PG pre-treatment. Chemical Oxygen Demand (COD) was selected to follow the performance of the photo-catalytic process and sonolysis. The experiments were based on a Central Composite Design (CCD) and analyzed by Response Surface Methodology (RSM). A mathematical model of the process was designed according to the proposed degradation scheme. Results The results showed that the maximum removal of PG occurred in ultrasonic/UV/WO3 in the presence of 50 mg/L WO3 and contact time of 120 minutes. In addition, an increase in the PG concentration caused a decrease in COD removal. As the initial concentration of the catalyst increased, the COD removal also increased. The maximum COD removal (91.3%) achieved by 200 mg/L WO3 and 400 mg/l ZnO, a contact time of 120 minutes, and an antibiotic concentration of 50 mg/L. All of the variables in the process efficiency were found to be significant (p < 0.05). Catalyst dose and contact time were shown to have a positive effect on the response (p < 0.05). Conclusion The research data supported the conclusion that the combination of advanced oxidation process of sonolysis and photocatalytic (sonophotocatalytic

  9. Removal of organic micro-pollutants from solid waste landfill leachate in membrane bioreactor operated without excess sludge discharge.

    Science.gov (United States)

    Boonyaroj, V; Chiemchaisri, C; Chiemchaisri, W; Yamamoto, K

    2012-01-01

    Two-stage membrane bioreactor (MBR) system was applied to the treatment of landfill leachate from a solid waste disposal site in Thailand. The first stage anoxic reactor was equipped with an inclined tube module for sludge separation. It was followed by an aerobic stage with a hollow fiber membrane module for solid liquid separation. Mixed liquor sludge from the aerobic reactor was re-circulated back to anoxic reactor in order to maintain constant mixed liquor suspended solids (MLSS) concentration in the aerobic reactor. The removal of micro-pollutants from landfill leachate along the treatment period of 300 days was monitored. The results indicated that two-stage MBRs could remove biochemical oxygen demand (BOD), chemical oxygen demand (COD) and NH(4)(+) by 97, 87 and 91% at steady operating condition. Meanwhile organic micro-pollutant removals were 50-76%. The removal efficiencies varied according to the hydrophobic characteristic of compounds but they were improved during long-term MBR operation without sludge discharge.

  10. Removal of Inorganic Nutrient and Organic Carbon from Wastewater of Binh Dien Market Using Green Alga Chlorella sp

    Directory of Open Access Journals (Sweden)

    Ha Bui Manh

    2016-12-01

    Full Text Available Traditional markets play a major role in socio-economics and constitutes a significant aspect of Vietnamese culture. However, wastewater streams discharged from the markets are generally characterized by a lot of inorganic nutrients and organic substances originated from fresh food processing units. They could lead to serious water contamination if discharged without proper treatment. This study applied microalgae Chlorella sp. for eliminating inorganic nutrients (NO3−-N, NH4+-N and PO43−-P and organic carbon (Chemical oxygen demand-COD from wastewater of the Binh Dien market. The removal efficiencies reached for NH4+-N > 86%, for NO3−-N > 72%, and for PO43−-P > 69%, respectively, at algal density of 49 × 104 cell mL−1, and for COD > 96% at algal density of 35 × 104 cell mL−1 after five cultivating days. The effluence satisfied the Vietnamese standard, column B, of the National technical regulation on industrial wastewater (QCVN 40:2011/BTNMT. The results demonstrated that the culture system composed of green algal Chlorella sp. could be a potential candidate for the removal of nutrients and organic carbon by a wastewater treatment process from the Binh Dien market.

  11. Organics and nitrogen removal from textile auxiliaries wastewater with A2O-MBR in a pilot-scale.

    Science.gov (United States)

    Sun, Faqian; Sun, Bin; Hu, Jian; He, Yangyang; Wu, Weixiang

    2015-04-01

    The removal of organic compounds and nitrogen in an anaerobic-anoxic-aerobic membrane bioreactor process (A(2)O-MBR) for treatment of textile auxiliaries (TA) wastewater was investigated. The results show that the average effluent concentrations of chemical oxygen demand (COD), ammonium nitrogen (NH4(+)-N) and total nitrogen (TN) were about 119, 3 and 48 mg/L under an internal recycle ratio of 1.5. The average removal efficiency of COD, NH4(+)-N and TN were 87%, 96% and 55%, respectively. Gas chromatograph-mass spectrometer analysis indicated that, although as much as 121 different types of organic compounds were present in the TA wastewater, only 20 kinds of refractory organic compounds were found in the MBR effluent, which could be used as indicators of effluents from this kind of industrial wastewater. Scanning electron microscopy analysis revealed that bacterial foulants were significant contributors to membrane fouling. An examination of foulants components by wavelength dispersive X-ray fluorescence showed that the combination of organic foulants and inorganic compounds enhanced the formation of gel layer and thus caused membrane fouling. The results will provide valuable information for optimizing the design and operation of wastewater treatment system in the textile industry.

  12. Application of electrochemical technology for removing petroleum hydrocarbons from produced water using lead dioxide and boron-doped diamond electrodes.

    Science.gov (United States)

    Gargouri, Boutheina; Gargouri, Olfa Dridi; Gargouri, Bochra; Trabelsi, Souhel Kallel; Abdelhedi, Ridha; Bouaziz, Mohamed

    2014-12-01

    Although diverse methods exist for treating polluted water, the most promising and innovating technology is the electrochemical remediation process. This paper presents the anodic oxidation of real produced water (PW), generated by the petroleum exploration of the Petrobras plant-Tunisia. Experiments were conducted at different current densities (30, 50 and 100 mA cm(-2)) using the lead dioxide supported on tantalum (Ta/PbO2) and boron-doped diamond (BDD) anodes in an electrolytic batch cell. The electrolytic process was monitored by the chemical oxygen demand (COD) and the residual total petroleum hydrocarbon [TPH] in order to know the feasibility of electrochemical treatment. The characterization and quantification of petroleum wastewater components were performed by gas chromatography mass spectrometry. The COD removal was approximately 85% and 96% using PbO2 and BDD reached after 11 and 7h, respectively. Compared with PbO2, the BDD anode showed a better performance to remove petroleum hydrocarbons compounds from produced water. It provided a higher oxidation rate and it consumed lower energy. However, the energy consumption and process time make useless anodic oxidation for the complete elimination of pollutants from PW. Cytotoxicity has shown that electrochemical oxidation using BDD could be efficiently used to reduce more than 90% of hydrocarbons compounds. All results suggest that electrochemical oxidation could be an effective approach to treat highly concentrated organic pollutants present in the industrial petrochemical wastewater and significantly reduce the cost and time of treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Removal of benzene and toluene in horizontal-flow anaerobic immobilized biomass reactor (HAIBR) in the presence of sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Cattony, E.B.M.; Chinalia, F.A.; Adorno, M.A.T.; Moraes, E.M.; Zaiat, M.; Foresti, E.; Varesche, M.B.A. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Biological Processes Laboratory

    2004-07-01

    The removal of toluene and benzene from organic waste by microorganisms was tested in two bioreactors. Two horizontal-flow anaerobic immobilized biomass (HAIB) reactors were fed with Zinder medium to stimulate anaerobic sulfate-reducing bacteria (SRB). The chemical oxygen demand (COD) and sulfate analysis were assessed and acetic acid, toluene and benzene were analyzed in gas chromatography. Microbial communities were characterized by fluorescence, optical electron microscopy and molecular biology analysis. The HAIB reactors achieved steady state within 2 weeks following hydrocarbon compound amendments. Depletion of sulfate was achieved after this time, along with removal of toluene and benzene. The inflow COD for both reactors was more than 95 per cent. The HAIB reactor operated under sulfidogenic conditions. It was concluded that the use of benzene and toluene is an efficient and cost-effective method for treating contaminated water, particularly for tropical developing countries. The study emphasized the importance of SRB populations in bioreactors to degrade organic aromatics under oxygen reduced conditions. 10 refs., 4 figs.

  14. Iodine nutrition and toxicity in Atlantic cod (Gadus morhua larvae

    Directory of Open Access Journals (Sweden)

    S Penglase

    2013-02-01

    Full Text Available Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I, at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua were fed rotifers enriched to intermediate (26 mg I kg-1 dry weight; MI group or copepod (129 mg I kg-1 DW; HI group I levels and compared to cod larvae fed control rotifers (0.6 mg I kg-1 DW. Larval I concentrations were increased by 3 (MI and 7 (HI fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg-1 DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg-1 DW.

  15. Electrochemical oxidation of COD from real textile wastewaters: Kinetic study and energy consumption.

    Science.gov (United States)

    Zou, Jiaxiu; Peng, Xiaolan; Li, Miao; Xiong, Ying; Wang, Bing; Dong, Faqin; Wang, Bin

    2017-03-01

    In the present study, the electrochemical oxidation of real wastewaters discharged by textile industry was carried out using a boron-doped diamond (BDD) anode. The effect of operational variables, such as applied current density (20-100 mA·cm(-2)), NaCl concentration added to the real wastewaters (0-3 g·L(-1)), and pH value (2.0-10.0), on the kinetics of COD oxidation and on the energy consumption was carefully investigated. The obtained experimental results could be well matched with a proposed kinetic model, in which the indirect oxidation mediated by electrogenerated strong oxidants would be described through a pseudo-first-order kinetic constant k. Values of k exhibited a linear increase with increasing applied current density and decreasing pH value, and an exponential increase with NaCl concentration. Furthermore, high oxidation kinetics resulted in low specific energy consumption, but this conclusion was not suitable to the results obtained under different applied current density. Under the optimum operational conditions, it only took 3 h to complete remove the COD in the real textile wastewaters and the specific energy consumption could be as low as 11.12 kWh·kg(-1) COD. The obtained results, low energy consumption and short electrolysis time, allowed to conclude that the electrochemical oxidation based on BDD anodes would have practical industrial application for the treatment of real textile wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Interaction between submicron COD crystals and renal epithelial cells

    Directory of Open Access Journals (Sweden)

    Peng H

    2012-08-01

    Full Text Available Hua Peng1,2 Jian-Ming Ouyang1,2 Xiu-Qiong Yao1, Ru-E Yang11Department of Chemistry, Jinan University, 2Institute of Biomineralization and Lithiasis Research, Jinan University, Guangzhou, ChinaObjectives: This study aims to investigate the adhesion characteristics between submicron calcium oxalate dihydrate (COD with a size of 150 ± 50 nm and African green monkey kidney epithelial cells (Vero cells before and after damage, and to discuss the mechanism of kidney stone formation.Methods: Vero cells were oxidatively injured by hydrogen peroxide to establish a model of injured cells. Scanning electron microscopy was used to observe Vero–COD adhesion. Inductively coupled plasma emission spectrometry was used to quantitatively measure the amount of adhered COD microcrystals. Nanoparticle size analyzer and laser scanning confocal microscopy were performed to measure the change in the zeta potential on the Vero cell surface and the change in osteopontin expression during the adhesion process, respectively. The level of cell injury was evaluated by measuring the changes in malonaldehyde content, and cell viability during the adhesion process.Results: The adhesion capacity of Vero cells in the injury group to COD microcrystals was obviously stronger than that of Vero cells in the control group. After adhesion to COD, cell viability dropped, both malonaldehyde content and cell surface zeta potential increased, and the fluorescence intensity of osteopontin decreased because the osteopontin molecules were successfully covered by COD. Submicron COD further damaged the cells during the adhesion process, especially for Vero cells in the control group, leading to an elevated amount of attached microcrystals.Conclusion: Submicron COD can further damage injured Vero cells during the adhesion process. The amount of attached microcrystals is proportional to the degree of cell damage. The increased amount of microcrystals that adhered to the injured epithelial

  17. Structure of chymotrypsin variant B from Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Leth-Larsen, Rikke; Asgeirsson, B; Thórólfsson, M

    1996-01-01

    The amino-acid sequence of chymotrypsin variant B isolated from the pyloric caeca of Atlantic cod has been elucidated. The characterization of the primary structure is based on N-terminal Edman degradation and mass spectrometry of the native protein and enzymatically derived peptides. Chymotrypsin...... side-chains may contribute to the maintenance of flexibility at low temperatures. Several amino-acid sequence differences adjacent to the catalytic site are observed in the two cod chymotrypsin variants which also differ in kinetic properties. Unlike the mammalian chymotrypsins, which contain several...

  18. Penurunan COD air limbah industri penyamakan kulit menggunakan reagen fenton

    Directory of Open Access Journals (Sweden)

    Muhammad Sholeh

    2013-06-01

    Full Text Available The aim of the experiment was to obtain optimum condition for COD reduction in tannery wastewater using fenton's reagent. The effects of different reaction parameters included ferrous concentration, hydrogen peroxide concentration, and the pH walue of solution were investigated. The optimum values were achieved at 0.2%, 120 ppm, and 4 for FeSO H O , and pH, 4, 2 2 respectively. The optimum condition still unable to fulfill the quality standard for COD of wastewater.

  19. Could seals prevent cod recovery in the Baltic Sea?

    DEFF Research Database (Denmark)

    MacKenzie, Brian; Eero, Margit; Ojaveer, Henn

    2011-01-01

    Fish populations are increasingly affected by multiple human and natural impacts including exploitation, eutrophication, habitat alteration and climate change. As a result many collapsed populations may have to recover in ecosystems whose structure and functioning differ from those in which...... in an ecosystem that likely will change due to both the already started recovery of a cod predator, the grey seal Halichoerus grypus, and projected climate impacts. Simulation modelling, assuming increased seal predation, fishing levels consistent with management plan targets and stable salinity, shows...... these goals will also depend on how climate change affects cod recruitment....

  20. A wasted resource: cod discards in the North Sea

    DEFF Research Database (Denmark)

    Feekings, Jordan P.; Poos, Jan Jaap; Aarts, Geert

    2012-01-01

    The public, political, and stakeholder perception of fisheries discards is that they are a waste of a valuable resource. In the North Sea, fisheries discards are some of the highest in the world. Cod (Gadus morhua) has contributed considerably to the amount discarded. The declining cod stock with......, spatially and temporally, in discarding over the past decade while pinpointing the major reasons to why it occurs. We discuss how such information can be used to improve future fishing activities and their subsequent catch compositions under a discard...

  1. The effect of the natural bentonite to reduce COD in palm oil mill effluent by using a hybrid adsorption-flotation method

    Science.gov (United States)

    Dewi, Ratni; Sari, Ratna; Syafruddin

    2017-06-01

    Palm oil mill effluent is waste produced from palm oil processing activities. This waste are comingfrom condensate water, process water and hydrocyclone water. The high levels of contaminants in the palm oil mill effluent causes the waste becomes inappropriate to be discharged to water body before processing, one of the most major contaminants in wastewater is fats, oils and COD.This study investigated the effectiveness of chemically activated bentonite that serves as an alternative to reduce the COD in adsorption and floatation based palm oil effluent waste processing. Natural bentonite was activated by using nitrit acid and benzene. In the existing adsorption material to improve COD reduction capability whereas the flotation method was used to further remove residual effluent which is still remain after the adsorption process. An adsorption columns which operated in batch was used in the present study. By varying the circulation time and adsorbent treatment (activated and non-activated), it was shown that percentage of COD reduction reached 75% at the circulation time of 180 minutes for non activated adsorbent. On the other hand the percentof COD reduction in adsorption and flotation process using activated bentonite reached as high as 88% and 93% at the circulation time of 180 minutes.

  2. Recovery in eastern Baltic cod: is increased recruitment caused by decreased predation on early life stages?

    DEFF Research Database (Denmark)

    Neumann, Viola; Köster, Fritz; Schaber, M.

    2014-01-01

    Cod (Gadus morhua) recruitment in the eastern Baltic Sea is influenced by predation on early life stages by sprat (Sprattus sprattus) and herring (Clupea harengus), which is considered as one of the mechanisms preventing cod recovery in the 1990s. In the light of improved cod recruitment in the s......Cod (Gadus morhua) recruitment in the eastern Baltic Sea is influenced by predation on early life stages by sprat (Sprattus sprattus) and herring (Clupea harengus), which is considered as one of the mechanisms preventing cod recovery in the 1990s. In the light of improved cod recruitment...

  3. Growth, temperature and density relationships of North Sea cod ( Gadus morhua )

    DEFF Research Database (Denmark)

    Rindorf, Anna; Jensen, Henrik; Schrum, Corinna

    2008-01-01

    This study presents an analysis of the relationship between ambient temperature, cod density, fishing mortality, prey fish biomass, and growth of North Sea cod (Gadus morhua) as estimated from survey catches during the period from 1983 to 2006. Growth of young cod was positively related to temper......This study presents an analysis of the relationship between ambient temperature, cod density, fishing mortality, prey fish biomass, and growth of North Sea cod (Gadus morhua) as estimated from survey catches during the period from 1983 to 2006. Growth of young cod was positively related...

  4. Pollutant removal performance of an integrated upflow-constructed wetland filled with haydites made of Al-based drinking water treatment residuals.

    Science.gov (United States)

    Wang, Wendong; Han, Yu; Liu, Hui; Zhang, Ke; Yue, Qiang; Bo, Longli; Wang, Xiaochang

    2017-05-01

    This study examined the pollutants removal performance of an integrated upflow-constructed wetland (IUCW) system in a 1.5 years' continuous operation. The average concentrations of chemical oxygen demand (COD), NH4-N, total nitrogen (TN), and total phosphorus (TP) in the effluent were 21.9, 1.47, 2.63, and 0.18 mg/L, respectively, which corresponded to 90.1%, 23.3%, 86.1%, and 97.2% removals from the raw water, respectively. The residual concentration of COD was 219 mg/L at start-up and decreased notably to 52.8 mg/L after 50 days of operation. NH4-N was difficult to remove because the average concentration of dissolved oxygen in the IUCW system was lower than 0.6 mg/L. In contrast, the residual concentrations of both TN and TP in the effluent were stable, with average removal rates as high as 89% and 99%, respectively, at start-up of the system. Changing the organic loading rates from 45.0 g/(m(2)·day) to 20.0 or 60.0 g/(m(2)·day) both inhibited the removal of TN. Further study showed that the removal of organic matter mainly occurred within 10-20 cm of the wetland cell. Considering its strong organic, nitrogen, and phosphate removal capacity, the IUCW system was determined to be effective in decentralized wastewater treatment.

  5. Chitosan on Reducing Chemical Oxygen Demands in Laundry Waste Water

    Directory of Open Access Journals (Sweden)

    Tri Joko

    2016-09-01

    Full Text Available Laundry liquid waste contains several chemical substances in detergent raw materials such as phosphate, surfactants, ammonia, and total suspended solids. The existence of detergent in high concentrations and exceeds the quality standards that have been estabilished in a body of water can lead to cases of enviromental pollution in the form of increased turbidity an Chemical Oxygen Demands (COD levels. Therefore in order to maintain and to ensure the availabillity of water in terms of quality, it requires coagulation-flocculation process to laundry liquid waste before discharging into water bodies. This study aims to determine the decrease of COD levels and turbidity level in laundry liquid waste using chitosan coagulant in “X” laundry, Tembalang District, Semarang. The research is a quasi experimental study with pretest-posttest with control group research design with 6 times replication. The total samples are 60 in wich 24 tested for the levels of turbidity and 6 controls. The test results of Kruskal-Wallis with significance p-value < 0,05 indicates that dosage variation (p=0,000 gives different levels of COD and dosage variation (p=0,000 provide 755,97 mg/l and the advantage levels of turbidity before treatment was 516,20 NTU. The optimum dosage of chitosan coagulant is on the dose of 200 mg/l with the effectiveness decrease of COD levels and turbidity levels on 72,67% an 98,67% respectively.

  6. Biological nutrient removal from meat processing wastewater using a sequencing batch reactor.

    Science.gov (United States)

    Thayalakumaran, N; Bhamidimarri, R; Bickers, P O

    2003-01-01

    Meat processing effluents are rich in nutrients (nitrogen: 75-200 mg L(-1) and phosphorus: 20-40 mg L(-1)) and COD (800-2,000 mg L(-1)) after primary treatment. A laboratory scale sequencing batch reactor (SBR) was operated for the treatment of a beef processing effluent from slaughtering and boning operations. An effective SBR cycle was found for removal of COD, nitrogen and phosphorus at 22 degrees C. The solid retention time was 15 days while the hydraulic retention time (HRT) was 2.5 days. The total nitrogen in the wastewater was reduced to less than 10 mg L(-1), while the total phosphorus decreased to less than 1.0 mg L(-1). The residual effluent soluble COD was found to be non-biodegradable as reflected by no further soluble COD removal following prolonged aeration. Removal of biodegradable soluble COD, ammonia nitrogen and soluble phosphate phosphorus of greater than 99% was achieved in the SBR. Good prediction of ammonia and nitrate nitrogen removal was obtained using IWA Activated Sludge Model. The operating cycle is shown to be appropriate to achieve simultaneous removal of COD and nutrients from the meat processing wastewater. Alkalinity and pH have an inverse relationship during the initial anaerobic and aerobic stages due to production and stripping of CO2. Use of a low level of DO in the final aerobic stage ensured complete ammonia removal and enhanced denitrification.

  7. Growth dynamics of saffron cod (Eleginus gracilis) and Arctic cod (Boreogadus saida) in the Northern Bering and Chukchi Seas

    Science.gov (United States)

    Helser, Thomas E.; Colman, Jamie R.; Anderl, Delsa M.; Kastelle, Craig R.

    2017-01-01

    Saffron cod (Eleginus gracilis) and Arctic cod (Boreogadus saida) are two circumpolar gadids that serve as critically important species responsible for energy transfer in Arctic food webs of the northern Bering and Chukchi Seas. To understand the potential effects of sea ice loss and warming temperatures on these species' basic life history, information such as growth is needed. Yet to date, limited effort has been dedicated to the study of their growth dynamics. Based on a large sample of otoliths collected in the first comprehensive ecosystem integrated survey in the northern Bering and Chukchi Seas, procedures were developed to reliably estimate age from otolith growth zones and were used to study the growth dynamics of saffron and Arctic cod. Annual growth zone assignment was validated using oxygen isotope signatures in otoliths and otolith morphology analyzed and compared between species. Saffron cod attained larger asymptotic sizes (L∞=363 mm) and achieved their maximum size at a faster rate (K=0.378) than Arctic cod (L∞=209 mm; K=0.312). For both species, regional differences in growth were found (pArctic cod grew to smaller asymptotic size but at faster rates in the more northerly central (L∞=197 mm;K=0.324) and southern Chukchi Sea (L∞=221 mm;K=0.297) when compared to the northern Bering Sea (L∞=266 mm;K=0.171), suggesting a possible cline in growth rates with more northerly latitudes. Comparison of growth to two periods separated by 30 years indicate that both species exhibited a decline in maximum size accompanied by higher instantaneous growth rates in more recent years.

  8. Combined biodegradation and ozonation for removal of tannins and dyes for the reduction of pollution loads.

    Science.gov (United States)

    Kanagaraj, James; Mandal, Asit Baran

    2012-01-01

    Tannins and dyes pose major threat to the environment by generating huge pollution problem. Biodegradation of wattle extract, chrome tannin and dye compounds using suitable fungal culture namely Aspergillus niger, Penicillium sp. were carried out. In addition to these, ozone treatment was carried out to get higher degradation rate. The results were monitored by carrying out chemical oxygen demand (COD), total organic carbon (TOC), and UV-Vis analysis. The results showed that wattle extract (vegetable tannin) gave better biodegradation rate than dye and chromium compounds. Biodegradation plus ozone showed degradation rates of 92-95%, 94-95%, and 85-87% for the wattle extract, dyes, chromium compounds, respectively. UV-Vis showed that there were no peaks observed for biodegraded samples indicating better degradation rates as compared to the control samples. FT-IR spectra analysis suggested that the formation of flavanoid derivatives, chromic oxide and NH(2) compounds during degradation of wattle extract, chromium and dye compounds, respectively, at the peaks of 1,601-1,629 cm(-1), 1,647 cm(-1), and 1,610-1,680 cm(-1). The present investigation shows that combination of biodegradation with ozone is the effective method for the removal of dyes and tannins. The biodegradation of the said compounds in combination with ozonation showed better rate of degradation than by chemical methods. The combination of biodegradation with ozone helps to reduce pollution problems in terms of COD, TOC, total dissolved solids and total suspended solids.

  9. Study of solar photo-Fenton system applied to removal of phenol from water.

    Science.gov (United States)

    Freire, Layla F A; da Fonseca, Fabiana Valéria; Yokoyama, Lidia; Teixeira, Luiz Alberto Cesar

    2014-01-01

    This study evaluated the use of a Fenton's reaction in a falling film solar reactor (FFR), as a possible advanced oxidation process for the mineralization of the organic compound phenol in water. Preliminary tests were carried out to evaluate phenol degradation by photolysis and to select the optimal residence time in which to carry out the process using a solar photo-Fenton system. The variables studied were the initial phenol concentration (100 to 300 mg L(-1)), the [Phenol]:[H2O2] mass ratio (1.0 to 2.0) and the [H2O2]/[Fe2+] molar ratio (5 to 10). Phenol degradation of 99% and chemical oxygen demand (COD) reduction of 97% were obtained under the following reaction conditions: phenol concentration=200 mg L(-1), mass ratio [Phenol]:[H2O2]=1.5 and molar ratio [H2O2]/[Fe2+]=7.5. Overall mineralization was achieved using the solar photo-Fenton process to destroy phenol and COD. The solar photo-Fenton process using a FFR appears to be a viable method for removing phenols in wastewaters on an industrial scale.

  10. Catalytic wet-oxidation of a mixed liquid waste: COD and AOX abatement.

    Science.gov (United States)

    Goi, D; de Leitenburg, C; Trovarelli, A; Dolcetti, G

    2004-12-01

    A series of catalytic wet oxidation (CWO) reactions, at temperatures of 430-500 K and in a batch bench-top pressure vessel were carried out utilizing a strong wastewater composed of landfill leachate and heavily organic halogen polluted industrial wastewater. A CeO2-SiO2 mixed oxide catalyst with large surface area to assure optimal oxidation performance was prepared. The catalytic process was examined during batch reactions controlling Chemical Oxygen Demand (COD) and Adsorbable Organic Halogen (AOX) parameters, resulting AOX abatement to achieve better effect. Color and pH were also controlled during batch tests. A simple first order-two stage reaction behavior was supposed and verified with the considered parameters. Finally an OUR test was carried out to evaluate biodegradability changes of wastewater as a result of the catalytic reaction.

  11. Performance and metabolic aspects of a novel enhanced biological phosphorus removal system with intermittent feeding and alternate aeration.

    Science.gov (United States)

    Melidis, Paraschos; Kapagiannidis, Anastasios G; Ntougias, Spyridon; Davididou, Konstantina; Aivasidis, Alexander

    2014-01-01

    A novel enhanced biological phosphorus removal (EBPR) system, which combined the intermittent feeding design with an anaerobic selector, was examined using on-line oxidation reduction potential (ORP), nitrate and ammonium probes. Two experimental periods were investigated: the aerobic and anoxic phases were set at 40 and 20 minutes respectively for period I, and set at 30 and 30 minutes for period II. Chemical oxygen demand (COD), biochemical oxygen demand (BOD5) and P removal were measured as high as 87%, 96% and 93% respectively, while total Kjeldahl nitrogen (TKN) and NH4(+) removal averaged 85% and 91%. Two specific denitrification rates (SDNRs), which corresponded to the consumption of the readily biodegradable and slowly biodegradable COD, were determined. SDNR-1 and SDNR-2 during period I were 0.235 and 0.059 g N g(-1) volatile suspended solids (VSS) d(-1) respectively, while the respective rates during period II were 0.105 and 0.042 g N g(-1) VSS d(-1). The specific nitrate formation and ammonium oxidizing rates were 0.076 and 0.064 g N g(-1) VSS d(-1) for period I and 0.065 and 0.081 g N g(-1) VSS d(-1) for period II respectively. The specific P release rates were 2.79 and 4.02 mg P g(-1) VSS h(-1) during period I and II, while the respective anoxic/aerobic uptake rates were 0.42 and 0.55 mg P g(-1) VSS h(-1). This is the first report on an EBPR scheme using the intermittent feeding strategy.

  12. The use of Moringa oleifera seed as a natural coagulant for wastewater treatment and heavy metals removal

    Science.gov (United States)

    Shan, Tan Chu; Matar, Manaf Al; Makky, Essam A.; Ali, Eman N.

    2016-11-01

    Moringa oleifera (MO) is a multipurpose tree with considerable potential and its cultivation is currently being actively promoted in many developing countries. Seeds of this tropical tree contain water-soluble, positively charged proteins that act as an effective coagulant for water and wastewater treatment. Based on this, water quality of "Sungai baluk" river was examined before and after the treatment using MO seed. MO seed exhibited high efficiency in the reduction and prevention of the bacterial growth in both wastewater and "Sungai baluk" river samples. The turbidity was removed up to 85-94% and dissolved oxygen (DO) was improved from 2.58 ± 0.01 to 4.00 ± 0.00 mg/L. The chemical oxygen demand (COD) and biological oxygen demand (BOD) were increased after the treatment from 99.5 ± 0.71 to 164.0 ± 2.83 mg/L for COD and from 48.00 ± 0.42 to 76.65 ± 2.33 mg/L for BOD, respectively. Nevertheless, there was no significant alteration of pH, conductivity, salinity and total dissolved solid after the treatment. Heavy metals such as Fe were fully eliminated, whereas Cu and Cd were successfully removed by up to 98%. The reduction of Pb was also achieved by up to 78.1%. Overall, 1% of MO seed cake was enough to remove heavy metals from the water samples. This preliminary laboratory result confirms the great potential of MO seed in wastewater treatment applications.

  13. The use of Moringa oleifera seed as a natural coagulant for wastewater treatment and heavy metals removal

    Science.gov (United States)

    Shan, Tan Chu; Matar, Manaf Al; Makky, Essam A.; Ali, Eman N.

    2017-06-01

    Moringa oleifera (MO) is a multipurpose tree with considerable potential and its cultivation is currently being actively promoted in many developing countries. Seeds of this tropical tree contain water-soluble, positively charged proteins that act as an effective coagulant for water and wastewater treatment. Based on this, water quality of "Sungai baluk" river was examined before and after the treatment using MO seed. MO seed exhibited high efficiency in the reduction and prevention of the bacterial growth in both wastewater and "Sungai baluk" river samples. The turbidity was removed up to 85-94% and dissolved oxygen (DO) was improved from 2.58 ± 0.01 to 4.00 ± 0.00 mg/L. The chemical oxygen demand (COD) and biological oxygen demand (BOD) were increased after the treatment from 99.5 ± 0.71 to 164.0 ± 2.83 mg/L for COD and from 48.00 ± 0.42 to 76.65 ± 2.33 mg/L for BOD, respectively. Nevertheless, there was no significant alteration of pH, conductivity, salinity and total dissolved solid after the treatment. Heavy metals such as Fe were fully eliminated, whereas Cu and Cd were successfully removed by up to 98%. The reduction of Pb was also achieved by up to 78.1%. Overall, 1% of MO seed cake was enough to remove heavy metals from the water samples. This preliminary laboratory result confirms the great potential of MO seed in wastewater treatment applications.

  14. Reduction of COD and Turbidity of Effluent in the Swine Productions Unit Employing Anaerobic Baffled Reactor (ABR Followed by Biological Filters and Sand Filter

    Directory of Open Access Journals (Sweden)

    Euzebio Beli

    2010-04-01

    Full Text Available The growing swine production is constantly in conflict with the environment due to the lack of environmental management directed to the cycle of animal production and the industrial sector, mainly due to the mishandling of slurry produced. In association with large concentrations of confined animals appear huge dumps of organic matter, inorganic nutrients and gaseous emissions, which require special care for its disposal to the environment. The aim of this study was to evaluate the use of an anaerobic baffled reactor (ABR in series with two downflow biological filters, followed by a sand filter as a polishing treatment. It were analyzed the reduction of COD and turbidity, and the behavior of pH in all phases of treatment. The removal of COD in the conjugated system, which occurred during treatment ranged from 74.55% to 94.41% with an average removal of 84.24%. In turn, the removal of turbidity from the period ranged from 53.07% to 96.11% with an average removal of 85.49%. In the studied period the pH changed from 5,6 to 8,4. This system was efficient in the removal of COD and turbidity of swine wastewater.

  15. Demand Forecasting Errors

    OpenAIRE

    Mackie, Peter; Nellthorp, John; Laird, James

    2005-01-01

    Demand forecasts form a key input to the economic appraisal. As such any errors present within the demand forecasts will undermine the reliability of the economic appraisal. The minimization of demand forecasting errors is therefore important in the delivery of a robust appraisal. This issue is addressed in this note by introducing the key issues, and error types present within demand fore...

  16. 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.

  17. Fluorescence of muscle and connective tissue from cod and salmon

    DEFF Research Database (Denmark)

    Andersen, Charlotte Møller; Wold, J.P.

    2003-01-01

    Autofluorescence of salmon and cod muscle was measured and compared with autofluorescence of collagen type I and type V. Similarities between fluorescence of fish muscle and collagen were found in that the same peaks were obtained around 390, 430, and 480 nm, These similarities are supported by p...

  18. Modelling axisymmetric cod-ends made of different mesh types

    DEFF Research Database (Denmark)

    Priour, D.; Herrmann, Bent; O'Neill, F.G.

    2009-01-01

    Cod-ends are the rearmost part of trawl fishing gears. They collect the catch, and for many important species it is where fish selection takes place. Generally speaking they are axisymmetric, and their shape is influenced by the catch volume, the mesh shape, and the material characteristics. The ...

  19. EAARL Coastal Topography–Cape Cod National Seashore, Massachusetts, 2002

    Science.gov (United States)

    Kranenburg, Christine; Hardy, Matthew; Nagle, David B.

    2017-01-01

    These datasets, prepared by the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center in collaboration with the National Park Service, provide lidar-derived first-surface and bare-earth topography for Cape Cod National Seashore, Massachusetts. Elevation measurements were acquired by the Experimental Advanced Airborne Research Lidar (EAARL) during October 2002.

  20. Exophiala angulospora causes systemic inflammation in atlantic cod Gadus morhua.

    Science.gov (United States)

    Gjessing, Mona Cecilie; Davey, Marie; Kvellestad, Agnar; Vrålstad, Trude

    2011-10-06

    Species of Exophiala are opportunistic fungal pathogens that may infect a broad range of warm- and cold-blooded animals, including salmonids and Atlantic cod. In the present study, we observed abnormal swimming behaviour and skin pigmentation and increased mortality in cod kept in an indoor tank. Necropsy revealed foci of different sizes with a greyish to brownish colour in internal organs of diseased fish. The foci consisted of ramifying darkly pigmented fungal hyphae surrounded by distinct layers of inflammatory cells, including macrophage-like cells. In the inner layer with many hyphae, the macrophage-like cells were dead. We observed no apparent restriction of fungal growth by the inflammatory response. A darkly pigmented fungus was repeatedly isolated in pure culture from foci of diseased fish and identified as Exophiala angulospora using morphological and molecular characters. This species has not been previously reported to cause disease in cod, but has been reported as an opportunistic pathogen of both marine and freshwater fish. Based on the morphology and sequence analysis presented here, we conclude that E. angulospora caused the observed chronic multifocal inflammation in internal organs of cod, leading to severe disease and mortality.

  1. Arctic Climate Change: A Tale of Two Cod Species

    Science.gov (United States)

    Arctic cod play an important role in the Arctic trophic hierarchy as the consumer of primary productivity and a food source for many marine fish and mammals. Shifts in their distribution and abundance could have cascading affects in the marine environment. This paper investigates...

  2. A staging system for larval cod (Gadus morhua L.)

    OpenAIRE

    1986-01-01

    A staging system of larval cod is described. The system is based on the resorption of the yolk mass and the cell layers surrounding it combined with eye, mouth and gut development. A determination key is given. Each stage is described in detail.

  3. Regime shifts, resilience and recovery of a cod stock

    DEFF Research Database (Denmark)

    Lindegren, Martin; Diekmann, Rabea; Möllmann, Christian

    2010-01-01

    In the North and Baltic seas Atlantic cod Gadus morhua stocks collapsed as part or one of the major factors inducing large-scale ecosystem regime shifts. Determining the relative contribution of overfishing and climate variability in causing these shifts has proven difficult. While facing similar...

  4. Groundwater Contamination Due to Activities of an Intensive Hog Farming Operation Located on a Geologic Fault in East Mediterranean: A Study on COD, BOD₅ and Microbial Load.

    Science.gov (United States)

    Michalopoulos, Charalampos; Tzamtzis, Nikolaos; Liodakis, Stylianos

    2016-02-01

    The application of treated animal wastewater produced in intensive fog farming operations (IHFOs) on surface soil, leads to groundwater contamination. In this study, the contamination of a Mediterranean aquifer caused by long-term application of treated wastewater, produced by an IHFO, on a plot with a geologic fault within the IHFO boundaries, was investigated. Groundwater samples were taken from monitoring wells close to the IHFO. A significant increase of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total viable count (TVC) and total coliform (TC) concentrations was found in wells, compared to control monitoring well, which were mainly affected by the subsurface flow of contaminated water, due to the presence of the geologic fault. During the winter, significant increases in concentrations of COD, BOD5, TVC and TC were noted and attributed to increased precipitation, which assisted in the accelerated transport of organic compounds and microbial load, through geologic fault, to groundwater.

  5. Removal of UV 254 nm matter and nutrients from a photobioreactor-wetland system.

    Science.gov (United States)

    Wu, Yonghong; He, Jiangzhou; Hu, Zhengyi; Yang, Linzhang; Zhang, Naiming

    2011-10-30

    The output of organic pollutants and excessive nutrients in intensive agricultural areas has frequently occurred, which easily lead to pollution events such as harmful algal blooms in downstream aquatic ecosystems. A photobioreactor-wetland system was applied to remove UV(254 nm) matter and dissolved nutrients discharged from an intensive agricultural area in the Kunming region of western China. The photobioreactor-wetland system was composed of two main components: an autotrophic photobioreactor with replanted macrophytes and a constructed wetland. The results showed that there was a significant correlation between UV(245)(nm) absorbance and chemical oxygen demand (COD) concentration in the effluent of the agricultural ecosystem. When the hydraulic load of the photobioreactor-wetland system was 500 m(3)day(-1), the UV(254 nm) absorbance was dramatically reduced, and dissolved nutrients such as TDP, NO(3)-N and NH(4)-N were effectively removed. The overall average removal efficiencies were as follows in relatively steady-state conditions: UV(254 nm) matter (66%), TDP (71%), NO(3)-N (75%) and NH(4)-N (65%). Simpson's diversity index of zoobenthos indicated that the system could increase the zoobenthic diversity and improve the growth conditions of the zoobenthos habitat. The results also showed that the photobioreactor-wetland system could remove the UV(254 nm) matter and dissolved nutrients, providing a promising bio-measure for reducing the risk of pollution event occurrences in downstream surface waters.

  6. Removal of hydrogen sulfide gas and landfill leachate treatment using coal bottom ash.

    Science.gov (United States)

    Lin, C Y; Hesu, P H; Yang, D H

    2001-06-01

    Coal bottom ashes produced from three thermal power plants were used in column and batch experiments to investigate the adsorption capacity of the coal ash. Hydrogen sulfide and leachates collected from three sanitary landfill sites were used as adsorbate gas and solutions, respectively. Experimental results showed that coal bottom ash could remove H2S from waste gas or reduce the concentrations of various pollutants in the leachate. Each gram of bottom ash could remove up to 10.5 mg of H2S. In treating the landfill leachate, increasing ash dosage increased the removal efficiency but decreased the adsorption amount per unit mass of ash. For these tested ashes, the removal efficiencies of chemical oxygen demand (COD), NH3-N, total Kjeldhal nitrogen (TKN), P, Fe3+, Mn2+, and Zn2+ were 36.4-50, 24.2-39.4, 27.0-31.1, 82.2-92.9, 93.8-96.5, 93.7-95.4, and 80.5-82.2%, respectively; the highest adsorption capacities for those parameters were 3.5-5.6, 0.22-0.63, 0.36-0.45, 0.027-0.034, 0.050-0.053, 0.029-0.032, and 0.006 mg/g of bottom ash, respectively. The adsorption of pollutants in the leachate conformed to Freundlich's adsorption model.

  7. Removal of organic matter and nitrogen from river water in a model floodplain.

    Science.gov (United States)

    Chung, Jong-Bae; Kim, Seung-Hyun; Jeong, Byeong-Ryong; Lee, Young-Deuk

    2004-01-01

    A significant improvement in river water quality cannot be expected unless nonpoint-source contaminants are treated in addition to the further treatment of point-source contaminants. If river water is sprayed over a floodplain, the consequent water filtration through the sediment profile can simultaneously remove organic matter and nitrogen in the water through aerobic and denitrifying reactions. This hypothesis was tested using lysimeters constructed from polyvinyl chloride (PVC) pipe (150 cm long, 15 cm in diameter) packed with loamy sand floodplain sediment. Water was applied to the top of the lysimeters at three different flow rates (48, 54, and 68 mm d(-1)). Concentrations of NO3 and dissolved oxygen (DO), chemical oxygen demand (COD), and redox potential (Eh) in the water were measured as functions of depth after the system reached steady states for both water flow and reactions. At the rate of 68.0 mm d(-1), a reducing condition for denitrification developed below the 5-cm depth due to the depletion of O2 by organic matter degradation in the surface oxidizing layer; Eh and DO were below 205 mV and 0.4 mg L(-1), respectively. At a depth of 70 cm, COD and NO3-N concentration decreased to 5.2 and 3.8 mg L(-1) from the respective influent concentrations of 17.1 and 6.2 mg L(-1). Most biodegradable organic matter was removed during flow and further removal of NO3 was limited by the lack of an electron donor (i.e., organic matter). These results indicate that the floodplain filtration technique has great promise for treatment of contaminated river water.

  8. Volatile Aromatic Compounds Removal in SBR: Study of Molecule Transfer and Conversion by Volatilisation and Degradation

    Science.gov (United States)

    Yin, Jun; Lesage, Geoffroy; Paul, Etienne; Sperandio, Mathieu

    2010-11-01

    The fate and transport of BTEX and naphthalene (NAP) in a lab-scale sequencing batch reactor (SBR) was investigated in this study. The synthetic wastewater feed contained readily biodegradable carbon sources, BTEX and NAP. There were two different operating conditions (phase1 and phase2) during the whole experiment. In phase2, 2,4-dichlorophenol (2,4-DCP) and 3,5-dimethylphenol (3,5-DMP) were added into the feed solution, which led to the sudden increase of SS in the effluent and decrease of MLSS and SVI. Good COD removal was achieved under steady state in both phases (>95%). During the entire operational period, BTEX and NAP were detected at very low level. According to COD mass balance, the fractions of COD loss accounted for the high percentage of the total COD in both phases. In spike tests, BTEX and NAP were quickly removed, and their concentrations declined to below 1 mgṡL-1 only wrthin one hour. In terms of OUR curve, obtained oxygen consumed for pollutants oxidation was very low. In addition, no intermediates were detected. The volatilization rate constants (κ) of BTEX and NAP were from 0.047 min-1 to 0.058 min-1. These combined results suggest that BTEX and NAP entering the reactor are removed mainly by volatilization and poor biodegradation, which is the main reason of high COD loss in the COD mass balance, as BTEX accounted for almost half of total COD in the feed.

  9. Colour and organic removal of biologically treated coffee curing wastewater by electrochemical oxidation method

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The treatment of biologically treated wastewater of coffee-curing industry by the electrochemical oxidation using steel anode were investigated. Bench-scale experiments were conducted for activated sludge process on raw wastewater and the treated effluents were further treated by electrochemical oxidation method for its color and organic content removal. The efficiency of the process was determined in terms of removal percentage of COD, BOD and color during the course of reaction. Several operating parameters like time, pH and current density were examined to ascertain their effects on the treatment efficiency. Steel anode was found to be effective for the COD and color removal with anode efficiency of 0.118 kgCOD-1A-1m-2 and energy consumption 20.61 kWh.kg-1 of COD at pH 9. The decrease in pH from 9 to 3 found to increase the anode efficiency from 0.118 kgCOD-1A-1m-2 to 0.144 kWh.kg-1 of COD while decrease the energy consumption from 20.61 kWh.kg-1 of COD to12 .86 kWh.kg-1 of COD. The pH of 5 was considered an ideal from the present treatment process as it avoids the addition of chemicals for neutralization of treated effluents and also economical with respect to energy consumption. An empirical relation developed for relationship between applied current density and COD removal efficiency showed strong predictive capability with coefficient of determination of 96.5%.

  10. It's a cod! Finding Nemo (impacted fishbone) in the emergency department.

    Science.gov (United States)

    McCabe, Aileen; Patton, Andrew; Salter, Nigel

    2017-06-15

    A 23-year-old woman presented to the emergency department (ED) with a sensation of a 'fish bone' stuck in her throat after eating cod. On physical examination, while she reported an uncomfortable sensation in her throat, no airway compromise was evident. Clinical examination, including ear, nose and throat (ENT) and oropharyngeal assessment, was unremarkable. A linear opacity consistent with a fishbone was visualised on a soft tissue lateral neck X-ray anterior to the vertebral body of C4-6. One attempt to visualise the fishbone on direct laryngoscopy failed in the ED. The fishbone was later removed the next day via direct visualisation with a flexible endoscope in the operating theatre by the ENT surgical team. The patient's recovery was uneventful. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. On the relation between water pools and water holding capacity in cod muscle

    DEFF Research Database (Denmark)

    Andersen, Charlotte Møller; Jørgensen, Bo

    2004-01-01

    measures of water holding capacity (WHC) in a way that WHC related to the original water content could be predicted well for the whole and the minced muscle. The centrifuged samples gave optimal predictions of WHC related to the dry matter content, probably because the centrifuged samples are similar......Low-field 1H nuclear magnetic resonance (NMR) relaxations were measured on muscle, minced muscle and centrifuged mince from cod that had been treated under various frozen and chill storage conditions. By using multi-way chemometrics, uni-exponential profiles were obtained, from which the transverse...... relaxation times (T2-values) and the water pool sizes (m- values) were determined. Three pools of water were identified with the different relaxation times and m-values in the centrifuged samples reflecting the removal of loosely bound water. The m-values and the full NMR-signal decays were correlated to two...

  12. Study on the Relationship Between Decolorization Rate and COD Value of Organic Pollutants%有机污染物的脱色率与COD值的关系研究

    Institute of Scientific and Technical Information of China (English)

    张金涛; 袁凤丹

    2014-01-01

    采用阳极氧化法制备了 TiO2纳米管阵列电极,采用场发射扫描电子显微镜(FESEM)和 X-射线衍射(XRD)对电极的表面形貌和晶型进行了表征,并以其为阳极对模拟染料废水甲基橙(MO)和亚甲基蓝(MB)溶液进行电化学氧化降解。研究了 MB溶液的电化学氧化降解反应动力学,考察了 MO和 MB溶液脱色率与 COD值之间的关系。结果表明,MB溶液在TiO2纳米管阵列电极表面发生电化学氧化降解反应动力学为一级反应;MO和MB溶液的脱色率与其COD值之间均呈良好的线性关系,可通过测定溶液脱色率来了解COD值的去除情况。%TiO2 Nanotube arrays electrode prepared by anodic oxidation method was acted as anode for elec-trochemical oxidation degradation of methyl orange(MO)and methylene blue(MB).The morphology and crys-tal structure of TiO2 nanotube arrays film were characterized by field emission scanning electron microscopy (FESEM)and X-ray diffraction(XRD),respectively.The kinetics of electrochemical oxidation degradation for MB solution was studied.The decolorization rates and chemical oxygen demand(COD)values of both MO and MB were measured in the process of degradation.Results indicated that electrochemical oxidation degradation of MB accorded with the first order reaction kinetics by the action of TiO2 nanotube arrays electrode.The linear relationships of decolorization rates and COD values of both MO and MB were obtained,which meant that the COD removal rate could be determined by the decolorization rates of them.

  13. Feeding opportunities of larval and juvenile cod (Gadus morhua) in a Greenlandic fjord: temporal and spatial linkages between cod and their preferred prey

    DEFF Research Database (Denmark)

    Swalethorp, Rasmus; Kjellerup, Sanne; Malanski, Evandro;

    2014-01-01

    preferences of the early-life stages of Atlantic cod (Gadus morhua) to quantify the availability of prey during a spring-summer season in a West Greenlandic fjord. We hypothesized that abundances of larval and juvenile cod at size were synchronized to optimal availability of preferred prey in space and time....... The present analysis is based on nine cruises each covering 5 stations visited between 24 May and 5 August 2010 comparing zooplankton abundance, cod gut content and distribution patterns. Cod 4–25 mm in length preferred prey of about 5 % of their own length. During ontogeny, their preferences changed from...

  14. Tetracycline removal during wastewater treatment in high-rate algal ponds

    Energy Technology Data Exchange (ETDEWEB)

    Godos, Ignacio de [School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North (New Zealand); Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011, Valladolid (Spain); Department of Biodiversity and Environmental Management, University of Leon, Campus Vegazana, 24071 Leon (Spain); Munoz, Raul [Department of Chemical Engineering and Environmental Technology, University of Valladolid, Dr. Mergelina s/n, 47011, Valladolid (Spain); Guieysse, Benoit, E-mail: B.J.Guieysse@massey.ac.nz [School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North (New Zealand)

    2012-08-30

    Highlights: Black-Right-Pointing-Pointer Tetracycline removal was most likely caused by photodegradation and biosorption. Black-Right-Pointing-Pointer Tetracycline presence was linked to biomass deflocculation and poor settleability. Black-Right-Pointing-Pointer Deflocculation did not impact treatment efficiency. Black-Right-Pointing-Pointer Deflocculation may hamper biomass recover during full-scale treatment. - Abstract: With the hypothesis that light supply can impact the removal of veterinary antibiotics during livestock wastewater treatment in high rate algal ponds (HRAPs), this study was undertaken to determine the mechanisms of tetracycline removal in these systems. For this purpose, two HRAPs were fed with synthetic wastewater for 46 days before tetracycline was added at 2 mg L{sup -1} to the influent of one of the reactors (Te-HRAP). From day 62, dissolved tetracycline removal stabilized around 69 {+-} 1% in the Te-HRAP and evidence from batch assays suggests that this removal was mainly caused by photodegradation and biosorption. Tetracycline addition was followed by the deflocculation of the Te-HRAP biomass but had otherwise no apparent impact on the removal of the chemical oxygen demand (COD) and biomass productivity. The results from the batch assays also suggested that the light-shading and/or pollutant-sequestrating effects of the biomass limited tetracycline removal in the pond. For the first time, these results demonstrate that the shallow geometry of HRAPs is advantageous to support the photodegradation of antibiotics during wastewater biological treatment but that the presence of these pollutants could hamper biomass recovery. These findings have significant implications for algal-based environmental biotechnologies and must be confirmed under field conditions.

  15. Removal of volatile fatty acids and ammonia recovery from unstable anaerobic digesters with a microbial electrolysis cell.

    Science.gov (United States)

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2016-11-01

    Continuous assays with a microbial electrolysis cell (MEC) fed with digested pig slurry were performed to evaluate its stability and robustness to malfunction periods of an anaerobic digestion (AD) reactor and its feasibility as a strategy to recover ammonia. When performing punctual pulses of volatile fatty acids (VFA) in the anode compartment of the MEC, simulating a malfunction of the AD process, an increase in the current density was produced (up to 14 times, reaching values of 3500mAm(-2)) as a result of the added chemical oxygen demand (COD), especially when acetate was used. Furthermore, ammonium diffusion from the anode to the cathode compartment was enhanced and the removal efficiency achieved up to 60% during daily basis VFA pulses. An AD-MEC combined system has proven to be a robust and stable configuration to obtain a high quality effluent, with a lower organic and ammonium content.

  16. Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences

    DEFF Research Database (Denmark)

    Zuo, Shaozhi; Huwer, Bastian; Bahlool, Qusay

    2016-01-01

    for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm......). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmothoë...

  17. Isolation of putative probionts from cod rearing environment

    DEFF Research Database (Denmark)

    Lauzon, H.L.; Gudmundsdottir, S.; Pedersen, M.H.;

    2008-01-01

    , metabolite production and adhesion to fish cell lines. Our study demonstrated that 14% of screened bacteria (n = 188) had antagonistic properties towards fish pathogens. The majority of these isolates were Gram-positive (81%), belonging to Firmicutes (69.2%) and Actinobacteria (11.5%) phyla based on 16S r...... was designed to search for new probiotics to target this critical period in cod rearing. Potential probionts were selected from the naturalmicrobiota of cod aquacultural environment. The selection was based on several criteria: pathogen inhibition potential, growth characteristics, strain identification......RNA gene sequencing. Only 6 (3.2%) of 188 isolates could inhibit all three pathogens tested: Vibrio anguillarum, Aeromonas salmonicida subsp. achromogenes and Vibrio salmonicida. Differences observed in activity intensity and spectrum among inhibitory isolates emphasise the need to develop probiotic...

  18. A sensometric approach to cod-quality measurement

    DEFF Research Database (Denmark)

    Jensen, H.S.; Jørgensen, Bo

    1997-01-01

    The quality index method was used for describing the sensory quality of thawed whole cod and raw fillet and the quality of boiled fillet was assessed by profiling analysis. These data were compared to the water holding capacity of the minced cod by principal component analysis (PCA) and partial...... least squares regression. The sensory data and the water holding capacity were correlated to an extent that made possible the prediction of high and low values of water holding capacity. Multivariate methods were also used for extracting some information about the assessor variability. This was done...... by determining the ability of the assessors to predict the water holding capacity through partial least squares regression and by examining the distances between PCA-models of profiling data from the single assessors. (C) 1997 Elsevier Science Ltd. All rights reserved....

  19. Achieving nitrogen removal via nitrite pathway from urban landfill leachate using the synergetic inhibition of free ammonia and free nitrous acid on nitrifying bacteria activity.

    Science.gov (United States)

    Sun, H W; Bai, Y; Peng, Y Z; Xie, H G; Shi, X N

    2013-01-01

    In this study, a biological system consisting of an up-flow anaerobic sludge blanket (UASB) and anoxic-oxic (A/O) reactor was established for the advanced treatment of high ammonium urban landfill leachate. The inhibitory effect of free ammonia (FA) and free nitrous acid (FNA) on the nitrifying bacterial activity was used to achieve stable nitritation in the A/O reactor. The results demonstrated that the biological system achieved chemical oxygen demand (COD), total nitrogen (TN) and NH(4)(+)-N removal efficiencies of 95.3, 84.6 and 99.2%, respectively at a low carbon-to-nitrogen ratio of 3:1. Simultaneous denitritation and methanogenesis in the UASB could improve the removal of COD and TN. Nitritation with above 90% nitrite accumulation was successfully achieved in the A/O reactor by synergetic inhibition of FA and FNA on the activity of nitrite oxidizing bacteria (NOB). Fluorescence in situ hybridization (FISH) analysis showed that ammonia oxidizing bacteria (AOB) was dominant and was considered to be responsible for the satisfactory nitritation performance.

  20. Excess post hypoxic oxygen consumption in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Plambech, M.; Deurs, Mikael van; Steffensen, J.F.;

    2013-01-01

    Atlantic cod Gadus morhua experienced oxygen deficit (DO2 ) when exposed to oxygen levels below their critical level (c. 73% of pcrit) and subsequent excess post-hypoxic oxygen consumption (CEPHO) upon return to normoxic conditions, indicative of an oxygen debt. The mean±s.e. CEPHO:DO2 was 6·9±1·......·9±1·5, suggesting that resorting to anaerobic energy production in severe hypoxia is energetically expensive...

  1. Excess post hypoxic oxygen consumption in Atlantic cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Plambech, M.; Deurs, Mikael van; Steffensen, J.F.

    2013-01-01

    Atlantic cod Gadus morhua experienced oxygen deficit (DO2 ) when exposed to oxygen levels below their critical level (c. 73% of pcrit) and subsequent excess post-hypoxic oxygen consumption (CEPHO) upon return to normoxic conditions, indicative of an oxygen debt. The mean±s.e. CEPHO:DO2 was 6......·9±1·5, suggesting that resorting to anaerobic energy production in severe hypoxia is energetically expensive...

  2. Avoidance from petroleum hydrocarbons by the cod (Gadus morhua)

    OpenAIRE

    Bøhle, Bjørn

    1982-01-01

    In laboratory experiments cod was presented a choice situation between different concentrations of petroleum hydrocarbons, appearing as "water soluble fraction" and emulsified droplets derived from Fuel Oil No. 2. In most experiments, the fishes seemed to avoid water containing hydrocarbons, though some fishes for periods was indifferent also to considerable contaminated water. The over all results indicates that a majority of the fishes avoided water containing total hyd...

  3. Cape Cod Easterly Shore Beach Erosion Study. Volume 2

    Science.gov (United States)

    1979-04-01

    bacterial slimes. In addition, these structures might provide roosting and nesting sites for certain bird species. Proposed structural and non-structural...Charles E. McClenne, Associate Professor, Colgate University, dated 3 August 1977 Notes from visit to Cape Cod Easterly Shores Beach Erosion Control...ments should be supported by factual information insofar as practicable. Oral statements will be heard but, for accuracy of record, all important facts

  4. Restructuring BOD : COD ratio of dairy milk industrial wastewaters in BOD analysis by formulating a specific microbial seed.

    Science.gov (United States)

    Dhall, Purnima; Siddiqi, T O; Ahmad, Altaf; Kumar, Rita; Kumar, Anil

    2012-01-01

    BOD (Biochemical oxygen demand) is the pollution index of any water sample. One of the main factors influencing the estimation of BOD is the nature of microorganisms used as seeding material. In order to meet the variation in wastewater characteristics, one has to be specific in choosing the biological component that is the seeding material. The present study deals with the estimation of BOD of dairy wastewater using a specific microbial consortium and compares of the results with seeding material (BODSEED). Bacterial strains were isolated from 5 different sources and were screened by the conventional BOD method. The selected microbial seed comprises of Enterobacter sp., Pseudomonas sp. BOD : COD (Chemical oxygen demand) ratio using the formulated seed comes in the range of 0.7-0.8 whereas that using BODSEED comes in the ratio of 0.5-0.6. The ultimate BOD (UBOD) was also performed by exceeding the 3-day dilution BOD test. After 90 days, it has been observed that the ratio of BOD : COD increased in case of selected consortium 7 up to 0.91 in comparison to 0.74 by BODSEED. The results were analyzed statistically by t-test and it was observed that selected consortium was more significant than the BODSEED.

  5. Positive regulation of botulinum neurotoxin gene expression by CodY in Clostridium botulinum ATCC 3502.

    Science.gov (United States)

    Zhang, Zhen; Dahlsten, Elias; Korkeala, Hannu; Lindström, Miia

    2014-12-01

    Botulinum neurotoxin, produced mainly by the spore-forming bacterium Clostridium botulinum, is the most poisonous biological substance known. Here, we show that CodY, a global regulator conserved in low-G+C Gram-positive bacteria, positively regulates the botulinum neurotoxin gene expression. Inactivation of codY resulted in decreased expression of botA, encoding the neurotoxin, as well as in reduced neurotoxin synthesis. Complementation of the codY mutation in trans rescued neurotoxin synthesis, and overexpression of codY in trans caused elevated neurotoxin production. Recombinant CodY was found to bind to a 30-bp region containing the botA transcription start site, suggesting regulation of the neurotoxin gene transcription through direct interaction. GTP enhanced the binding affinity of CodY to the botA promoter, suggesting that CodY-dependent neurotoxin regulation is associated with nutritional status.

  6. Association between nematode Hysterothylacium aduncum invasion of cod larvae and growth

    DEFF Research Database (Denmark)

    Mehrdana, Foojan; Bahlool, Qusay Z. M.; Kuhn, Jesper;

    invertebrates and fish species and for some species also higher vertebrate hosts. We have recently demonstrated that fry of North Sea cod has a high prevalence of infection with regard to the nematode Hysterothylacium aduncum and it was indicated that these infections could affect survival of cod and thereby...... affect the cod stock in the North Sea. The objective of the present study was to elucidate if infections are associated with a decrease or an increase of fish size when examining fish of the same age. We investigated effects of H. aduncum infections on the growth rate of cod larvae by using the otolith...... reading method. In our study, the prevalence of infection with H. aduncum in North Sea cod Gadus morhua larvae was studied during the years 1992-2001. A subsample of 65 cod was selected based on the body length (range 20 to 45 mm) with 32 infected and 33 uninfected fishes. For ageing the cod larvae...

  7. COD::CIF::Parser: an error-correcting CIF parser for the Perl language.

    Science.gov (United States)

    Merkys, Andrius; Vaitkus, Antanas; Butkus, Justas; Okulič-Kazarinas, Mykolas; Kairys, Visvaldas; Gražulis, Saulius

    2016-02-01

    A syntax-correcting CIF parser, COD::CIF::Parser, is presented that can parse CIF 1.1 files and accurately report the position and the nature of the discovered syntactic problems. In addition, the parser is able to automatically fix the most common and the most obvious syntactic deficiencies of the input files. Bindings for Perl, C and Python programming environments are available. Based on COD::CIF::Parser, the cod-tools package for manipulating the CIFs in the Crystallography Open Database (COD) has been developed. The cod-tools package has been successfully used for continuous updates of the data in the automated COD data deposition pipeline, and to check the validity of COD data against the IUCr data validation guidelines. The performance, capabilities and applications of different parsers are compared.

  8. Measuring the price responsiveness of gasoline demand: economic shape restrictions and nonparametric demand estimation

    OpenAIRE

    Blundell, Richard; Horowitz, Joel L.; Parey, Matthias

    2011-01-01

    This paper develops a new method for estimating a demand function and the welfare consequences of price changes. The method is applied to gasoline demand in the U.S. and is applicable to other goods. The method uses shape restrictions derived from economic theory to improve the precision of a nonparametric estimate of the demand function. Using data from the U.S. National Household Travel Survey, we show that the restrictions are consistent with the data on gasoline demand and remove the anom...

  9. Effect of produced water on cod (Gadus morhua) immune responses

    Energy Technology Data Exchange (ETDEWEB)

    Hamoutene, D.; Mabrouk, G.; Samuelson, S.; Mansour, A.; Lee, K. [Fisheries and Oceans Canada, Dartmouth, NS (Canada). Maritimes Region, Ocean Sciences Division; Volkoff, H.; Parrish, C. [Memorial Univ. of Newfoundland, St. John' s, NL (Canada); Mathieu, A. [Oceans Ltd., St. John' s, NL (Canada)

    2007-07-01

    Studies have shown that produced water (PW) discharged from North Sea offshore platforms affects the biota at greater distances from operational platforms than originally presumed. According to PW dispersion simulations, dilution by at least 240 times occurs within 50-100 m, and up to 9000 times by 20 km from the discharge. In this study, the effect of PW on cod immunity was investigated by exposing fish to 0, 100 ppm (x 10,000 dilution) or 200 ppm (x 500) of PW for 76 days. Immune responses were evaluated at the end of the exposure. Fish from the 3 groups were injected with Aeromonas salmonicida lipopolysaccharides (LPS). Blood cell observation and flow cytometry were used to investigate the serum cortisol levels and gill histology along with ratios and respiratory burst (RB) responses of both circulating and head-kidney white blood cells (WBCs). The study revealed that baseline immunity and stress response were not affected by PW, other than an irritant-induced change in gill cells found in treated cod. In all groups, LPS injection resulted in a pronounced decrease in RB of head-kidney cells and an increase in serum cortisol and protein levels. However, the group exposed to 200 ppm of PW exhibited the most significant changes. LPS injection was also shown to influence WBC ratios, but further studies are needed to determine if this impact is stronger in fish exposed to PW. This study suggested an effect of PW on cod immunity after immune challenge with LPS.

  10. Hair Removal

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Hair Removal KidsHealth > For Teens > Hair Removal A A A ... recommend an electrologist with the proper credentials. Laser Hair Removal How It Works: A laser is directed through ...

  11. Hair Removal

    Science.gov (United States)

    ... Surgery? Choosing the Right Sport for You Shyness Hair Removal KidsHealth > For Teens > Hair Removal Print A ... you need any of them? Different Types of Hair Before removing hair, it helps to know about ...

  12. Enhanced biological nutrients removal using an integrated oxidation ditch with vertical circle from wastewater by adding an anaerobic column

    Institute of Scientific and Technical Information of China (English)

    WANG Shu-mei; LIU Jun-xin

    2005-01-01

    Compared to conventional oxidation ditches, an integrated oxidation ditch with vertical circle(IODVC) has the characters of concise configuration, simple operation and maintenance, land saving and automatical sludge returning. By the utilization of vertical circulation, an aerobic zone and an anoxic zone can be unaffectedly formed in the IODVC. Therefore, COD and nitrogen can be efficiently removed. However, the removal efficiency of phosphorus was Iow in the IODVC. In the experiment described, a laboratory scale system to add an anaerobic column to the IODVC has been tested to investigate the removal of phosphorus from wastewater. The experimental results showed that the removal efficiency of TP with the anaerobic column was increased to 54.0 % from 22.3 % without the anaerobic column. After the acetic sodium was added into the influent as carbon sources, the mean TP removal efficency of 77.5 % was obtained. At the same time, the mean removal efficiencies of COD, TN and NH3-N were 92.2%, 81.6% and 98.1%, respectively, at 12 h of HRT and 21-25 d of SRT. The optimal operational conditions in this study were as follows: recycle rate = 1.5-2.0, COD/TN > 6, COD/TP > 40,COD loading rate = 0.26-0.32 kgCOD/(kgSS·d), TN loading rate =0.028-0.034 kgTN/(kgSS·d) and TP loading rate = 0.003-0.005kgTP/(kgSS·d), respectively.

  13. Combined anaerobic–ozonation process for treatment of textile wastewater: Removal of acute toxicity and mutagenicity

    Energy Technology Data Exchange (ETDEWEB)

    Punzi, Marisa, E-mail: marisa.punzi@biotek.lu.se [Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Nilsson, Filip [Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Anbalagan, Anbarasan [Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Svensson, Britt-Marie [School of Education and Environment, Kristianstad University, SE-291 88 Kristianstad (Sweden); Jönsson, Karin [Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden); Mattiasson, Bo; Jonstrup, Maria [Department of Biotechnology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden)

    2015-07-15

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

  14. IC/MBBR工艺处理高COD、高氨氮煤化工废水%IC/MBBR Process for Treatment of High COD and Ammonia Nitrogen Wastewater

    Institute of Scientific and Technical Information of China (English)

    魏谷

    2012-01-01

    采用IC/MBBR生化工艺处理煤化工生产废水.通过监测COD的去除效果和产气状况,分析了IC厌氧反应器启动及负荷期间的运行情况;通过监测VFA、ALK和pH值的变化趋势分析了IC厌氧反应器的酸化及恢复情况.MBBR反应器启动期间对氨氮的去除率高于COD;通过氮衡算,发现反应器中存在非传统的硝化/反硝化脱氮途径,这一现象在运行期间的氧利用估算中得到进一步证实.%IC/MBBR was used as bio-process to treat coal chemical wastewater. The operation status of IC anaerobic reactor during start-up and loading was analyzed by monitoring COD removal and gas production. The acidification and recovery of IC anaerobic reactor were also analyzed by monitoring VFA, ALK and pH. During MBBR start-up, the removal rate of NH3 - N was higher than that of COD. It was found by nitrogen balance calculation that a non-nitrification/denitrification pathway for nitrogen removal existed in the reactor. This phenomenon was verified by oxygen consumption estimation during the operation.

  15. Isolation of a Halophilic Bacterium, Bacillus sp. Strain NY-6 for Organic Contaminants Removal in Saline Wastewater on Ship

    Institute of Scientific and Technical Information of China (English)

    Jie Gao; Zhenjiang Yu; Xiaohui Zhang; Dan Zhao; Fangbo Zhao

    2013-01-01

    The objective of this research was to examine if certain strains of Bacillus bacteria,could survive in dry powder products and if so,could the bacteria degrade organic contaminants in saline wastewater on a ship.As part of the study,we isolated 7 domesticated strains named NY1,NY2,…,and NY7,the strain NY6 showed to have the best performance for organic matter degradation and could survive in dry powder more than 3 months.NY6 was identified as Bacillus aerius,based on the morphological and physic-chemical properties.Its optimal growth conditions were as follows:salinity was 2%; temperature was 37℃; pH was in 6.5-7.0; best ratio of C∶ N∶ P was 100∶5∶1.The capability of its dry powder for Chemical Oxygen Demand (COD) removal was 800mg COD/g in synthesized marine wastewater with 2% salinity.The spores in the dry powder were 1.972× 108 g1.

  16. Performance evaluation of a photo-Fenton process applied to pollutant removal from textile effluents in a batch system.

    Science.gov (United States)

    Módenes, A N; Espinoza-Quiñones, F R; Manenti, D R; Borba, F H; Palácio, S M; Colombo, A

    2012-08-15

    In this work, the performance of a photo-Fenton process-based textile effluent treatment was investigated using both solar and artificial light sources. A full 3(3) factorial experimental design was applied for the optimisation with respect to three parameters: initial pH, amounts of Fe(2+) (0.01-0.09 g L(-1)) and H(2)O(2) (1-7 g L(-1)). The photo-Fenton process response was evaluated on the basis of chemical oxygen demand (COD) removal and decolourisation. The optimum conditions of the photo-Fenton process were attained at concentration values of 0.05 g Fe(2+) L(-1) and 6.0 g H(2)O(2) L(-1) and pH 3, for both solar and artificial light sources. The effects of initial pH, and Fe(2+) and H(2)O(2) concentrations were evaluated. From the monitoring of TOC, COD, turbidity and decolourisation over time, the progress of the mineralisation of dyes was analysed, forming nitrate, ammonia nitrogen and nitrite. Low amounts of residual peroxide and iron, which were below the limit allowed by Brazilian environmental legislation, were attained after 360 min of irradiation time for both artificial and solar sources. An operational cost of US$ 6.85 per m(3) of treated effluent was estimated using solar irradiation.

  17. Novel Local Calibration Method for Chemical Oxygen Demand Measurements by Using UV-Vis Spectrometry

    Science.gov (United States)

    Yingtian, Hu; Chao, Liu; Xiaoping, Wang

    2017-05-01

    In recent years, ultraviolet-visible spectroscopy has been widely used for chemical oxygen demand (COD) measurements of water. However, chemical compositions of substance in different water samples can cause measurement deviations, so a local calibration is needed. In this study, a novel local calibration method is proposed. The absorption spectra of COD standard solutions and wastewater samples taken from four factories were collected. We analyzed the impact of chemical compositions of substance in different water samples and extracted the morphology features of their absorptive spectra for recognition models. Furthermore, we calculated the local calibration parameters of the four categories of real water samples by specific modification based on the ability of light absorption in various water environments. After the process of local calibration, the root mean square errors (RMSEs) of the predictions were very small, which highlights the potential of this method for improving the accuracy and adaptability of COD measurements based on ultraviolet-visible spectrum.

  18. Study on Determination of Chemical Oxygen Demand in Water with Ion Chromatography

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhong-Hai; DING Hong-Chun; FANG Yan-Ju; XIAN Yue-Zhong; JIN Li-Tong

    2007-01-01

    A new method for determining chemical oxygen demand (COD) value in water using ion chromatography coupled with nano TiO2-K2S2O8 co-existing system was described. The photocatalytic oxidation system and nano TiO2-K2S2O8 co-existing system could degrade the organic compounds in water. All sulfur-containing species in the reactive solution were eventually transformed to sulfate which could be determined by conductivity detector in ion chromatography. The change of conductivity of sulfate was proportional to COD value. The optimal experimental conditions and the mechanism of the detection were discussed. The application range was 10.0-300.0 mg·L -1 and the lowest limit of detection was 3.5 mg·L -1. It was considered that the value obtained could be reliably correlated with the COD value obtained using the conventional methods.

  19. Inhibition of haemoglobin-mediated lipid oxidation in washed cod muscle and cod protein isolates by Fucus vesiculosus extract and fraction

    DEFF Research Database (Denmark)

    Wang, Tao; Jonsdottir, Rosa; Kristinsson, Hordur

    2010-01-01

    The effects of Fucus vesiculosus extract and fractions towards haemoglobin- (Hb-) catalysed lipid oxidation in washed cod muscle system and cod protein isolates during ice storage were examined. The extract and fractions were characterised in terms of total phlorotannin content (TPC), 2,2-diphenyl...

  20. Inhibition of haemoglobin-mediated lipid oxidation in washed cod muscle and cod protein isolates by Fucus vesiculosus extract and fraction

    DEFF Research Database (Denmark)

    Wang, Tao; Jonsdottir, Rosa; Kristinsson, Hordur

    2010-01-01

    The effects of Fucus vesiculosus extract and fractions towards haemoglobin- (Hb-) catalysed lipid oxidation in washed cod muscle system and cod protein isolates during ice storage were examined. The extract and fractions were characterised in terms of total phlorotannin content (TPC), 2,2-diphenyl...

  1. Comparison of the MBBR denitrification carriers for advanced nitrogen removal of wastewater treatment plant effluent.

    Science.gov (United States)

    Yuan, Quan; Wang, Haiyan; Hang, Qianyu; Deng, Yangfan; Liu, Kai; Li, Chunmei; Zheng, Shengzhi

    2015-09-01

    The moving bed biofilm reactors (MBBRs) were used to remove the residual NO3(-)-N of wastewater treatment plant (WWTP) effluent, and the MBBR carriers for denitrification were compared. The results showed that high denitrification efficiency can be achieved with polyethylene, polypropylene, polyurethane foam, and haydite carriers under following conditions: 7.2 to 8.0 pH, 24 to 26 °C temperature, 12 h hydraulic retention time (HRT), and 25.5 mg L(-1) external methanol dosage, while the WWTP effluent total nitrogen (TN) was between 2.6 and 15.4 mg L(-1) and NO3(-)-N was between 0.2 and 12.6 mg L(-1). The MBBR filled with polyethylene carriers had higher TN and NO3(-)-N removal rate (44.9 ± 19.1 and 83.4 ± 13.0%, respectively) than those with other carriers. The minimum effluent TN and NO3(-)-N of polyethylene MBBR were 1.6 and 0.1 mg L(-1), respectively, and the maximum denitrification rate reached 23.0 g m(-2) day(-1). When chemical oxygen demand (COD)/TN ratio dropped from 6 to 4, the NO3(-)- N and TN removal efficiency decreased significantly in all reactors except for that filled with polyethylene, which indicated that the polyethylene MBBR can resist influent fluctuation much better. The three-dimensional excitation-emission matrix analysis showed that all the influent and effluent of MBBRs contain soluble microbial products (SMPs)-like organics and biochemical oxygen demand (BOD), which can be removed better by MBBRs filled with haydite and polyethylene carriers. The nitrous oxide reductase (nosZ)-based terminal restriction fragment length polymorphism (T-RFLP) analysis suggested that the dominant bacteria in polyethylene MBBR are the key denitrificans.

  2. Innovation and Demand

    DEFF Research Database (Denmark)

    Andersen, Esben Sloth

    2007-01-01

    the demand-side of markets in the simplest possible way. This strategy has allowed a gradual increase in the sophistication of supply-side aspects of economic evolution, but the one-sided focus on supply is facing diminishing returns. Therefore, demand-side aspects of economic evolution have in recent years...... received increased attention. The present paper argues that the new emphasis on demand-side factors is quite crucial for a deepened understanding of economic evolution. The major reasons are the following: First, demand represents the core force of selection that gives direction to the evolutionary process....... Second, firms' innovative activities relate, directly or indirectly, to the structure of expected and actual demand. Third, the demand side represents the most obvious way of turning to the much-needed analysis of macro-evolutionary change of the economic system....

  3. Performance of rotating drum biofilter for volatile organic compound removal at high organic loading rates

    Institute of Scientific and Technical Information of China (English)

    YANG Chunping; CHEN Hong; ZENG Guangming; ZHU Xueqing; SUIDAN Makram T

    2008-01-01

    Uneven distribution of volatile organic compounds (VOCs) and biomass,and excess biomass accumulation in some biofilters hinder the application of biofiltration technology.An innovative multilayer rotating drum biofilter (RDB) was developed to correct these problems.The RDB was operated at an empty bed contact time (EBCT) of 30 s and a rotational rate of 1.0 r/rain.Diethyl ether was chosen as the model VOC.Performance of the RDB was evaluated at organic loading rates of 32.1,64.2,128,and 256 g ether/(m3·h) (16.06 g ether/(m3·h) ≈1.0 kg chemical oxygen demand (COD)/(m3·d)).The EBCT and organic loading rates were recorded on the basis of the medium volume.Results show that the ether removal efficiency decreased with an increased VOC loading rate.Ether removal efficiencies exceeding 99% were achieved without biomass control even at a high VOC loading rate of 128 g ether/(m3·h). However,when the VOC loading rate was increased to 256 g ether/(m3·h),the average removal efficiency dropped to 43%.Nutrient limitation possibly contributed to the drop in ether removal efficiency.High biomass accumulation rate was also observed in the medium at the two higher ether loading rates,and removal of the excess biomass in the media was necessary to maintain stable performance. This work showed that the RDB is effective in the removal of diethyl ether from waste gas streams even at high organic loading rates. The results might help establish criteria for designing and operating RDBs.

  4. Standardization of BOD₅/COD ratio as a biological stability index for MSW.

    Science.gov (United States)

    Cossu, Raffaello; Lai, Tiziana; Sandon, Annalisa

    2012-08-01

    The control of biodegradable substances is the key issue in evaluating the short and long-term emission potential and environmental impact of a landfill. Aerobic and anaerobic indices, such as respirometric index (RI) and biomethane potential production (GB21), can be used in the estimation of the stability of solid waste samples. Previous studies showed different degrees of relationship between BOD₅/COD ratio compared with RI4. Aim of this study is to standardize the parameter BOD₅/COD ratio and to test the methodology under different operating conditions (dynamic or static leaching and leaching duration, 6 and 24-h) keeping constant temperature and liquid/solid ratio (L/S=10 l/kg(TS)), with the introduction of a COD fractioning method. The COD fractioning is based on the differentiation between the soluble fraction (COD(sol)) and the colloidal fraction (COD(coll)) using a flocculation method. The BOD₅/COD and the BOD₅/COD(sol) indices are both consistent and significant and can be used as stability indices. The BOD₅/COD ratio does not seem to be influenced, for the same test duration, by the type of test, static or dynamic. In the same way the longer test duration (24-h) does not influence significantly the values of BOD₅/COD ratio. As a consequence a leaching test duration of 6-h is preferable to avoid the beginning of the hydrolysis and oxidation processes.

  5. The effect of biological sulfate reduction on anaerobic color removal in anaerobic-aerobic sequencing batch reactors.

    Science.gov (United States)

    Cirik, Kevser; Kitis, Mehmet; Cinar, Ozer

    2013-05-01

    Combination of anaerobic-aerobic sequencing processes result in both anaerobic color removal and aerobic aromatic amine removal during the treatment of dye-containing wastewaters. The aim of the present study was to gain more insight into the competitive biochemical reactions between sulfate and azo dye in the presence of glucose as electron donor source. For this aim, anaerobic-aerobic sequencing batch reactor fed with a simulated textile effluent including Remazol Brilliant Violet 5R (RBV 5R) azo dye was operated with a total cycle time of 12 h including anaerobic (6 h) and aerobic cycles (6 h). Microorganism grown under anaerobic phase of the reactor was exposed to different amounts of competitive electron acceptor (sulfate). Performance of the anaerobic phase was determined by monitoring color removal efficiency, oxidation reduction potential, color removal rate, chemical oxygen demand (COD), color, specific anaerobic enzyme (azo reductase) and aerobic enzyme (catechol 1,2-dioxygenase), and formation of aromatic amines. The presence of sulfate was not found to significantly affect dye decolorization. Sulfate and azo dye reductions took place simultaneously in all operational conditions and increase in the sulfate concentration generally stimulated the reduction of RBV 5R. However, sulfate accumulation under anaerobic conditions was observed proportional to increasing sulfate concentration.

  6. Combined Pre-Precipitation, Biological Sludge Hydrolysis and Nitrogen Reduction - A Pilot Demonstration of Integrated Nutrient Removal

    DEFF Research Database (Denmark)

    Kristensen, G. H.; Jørgensen, P. E.; Strube, R.

    1992-01-01

    A pilot study was performed to investigate advanced wastewater treatment by pre-precipitation in combination with biological nitrogen removal supported by biological sludge hydrolysis. The influent wastewater was pretreated by addition of a pre-polymerized aluminum salt, followed by flocculation...... solubilization was 10-13% of the suspended COD. The liquid phase of the hydrolyzed sludge, the hydrolysate, was separated from the suspended fraction by centrifugation and added to the biological nitrogen removal stage to support denitrification. The hydrolysate COD consisted mainly of volatile fatty acids......, resulting in high denitrification rates. Nitrogen reduction was performed based on the Bio-Denitro principle in an activated sludge system. Nitrogen was reduced from 45 mg/l to 9 mg/l and phosphorus was reduced from 11 mg/l to 0.5 mg/l. The sludge yield was low, approx. 0.3-0.4 gCOD/gCOD removed...

  7. Combined Pre-Precipitation, Biological Sludge Hydrolysis and Nitrogen Reduction - A Pilot Demonstration of Integrated Nutrient Removal

    DEFF Research Database (Denmark)

    Kristensen, G. H.; Jørgensen, P. E.; Strube, R.

    1992-01-01

    A pilot study was performed to investigate advanced wastewater treatment by pre-precipitation in combination with biological nitrogen removal supported by biological sludge hydrolysis. The influent wastewater was pretreated by addition of a pre-polymerized aluminum salt, followed by flocculation...... solubilization was 10-13% of the suspended COD. The liquid phase of the hydrolyzed sludge, the hydrolysate, was separated from the suspended fraction by centrifugation and added to the biological nitrogen removal stage to support denitrification. The hydrolysate COD consisted mainly of volatile fatty acids......, resulting in high denitrification rates. Nitrogen reduction was performed based on the Bio-Denitro principle in an activated sludge system. Nitrogen was reduced from 45 mg/l to 9 mg/l and phosphorus was reduced from 11 mg/l to 0.5 mg/l. The sludge yield was low, approx. 0.3-0.4 gCOD/gCOD removed...

  8. PERFECT DEMAND ILLUSION

    Directory of Open Access Journals (Sweden)

    Alexander Yu. Sulimov

    2015-01-01

    Full Text Available The article is devoted to technique «Perfect demand illusion», which allows to strengthen the competitive advantageof retailers. Also in the paper spells out the golden rules of visual merchandising.The definition of the method «Demand illusion», formulated the conditions of its functioning, and is determined by the mainhypothesis of the existence of this method.Furthermore, given the definition of the «Perfect demand illusion», and describes its additional conditions. Also spells out the advantages of the «Perfect demandillusion», before the «Demand illusion».

  9. Divers of Passenger Demand

    OpenAIRE

    Wittmer, Andreas

    2011-01-01

    -Overview drivers of passenger demand -Driver 1: Economic growth in developing countries -Driver 2: International business travel in developed countries -Driver 3: International leisure travel in developed countries

  10. Membrane biofilm development improves COD removal in anaerobic membrane bioreactor wastewater treatment.

    Science.gov (United States)

    Smith, Adam L; Skerlos, Steven J; Raskin, Lutgarde

    2015-09-01

    Membrane biofilm development was evaluated to improve psychrophilic (15°C) anaerobic membrane bioreactor (AnMBR) treatment of domestic wastewater. An AnMBR containing three replicate submerged membrane housings with separate permeate collection was operated at three levels of membrane fouling by independently controlling biogas sparging for each membrane unit. High membrane fouling significantly improved permeate quality, but resulted in dissolved methane in the permeate at a concentration two to three times the equilibrium concentration predicted by Henry's law. Illumina sequencing of 16S rRNA targeting Bacteria and Archaea and reverse transcription-quantitative polymerase chain reaction targeting the methyl coenzyme-M reductase (mcrA) gene in methanogens indicated that the membrane biofilm was enriched in highly active methanogens and syntrophic bacteria. Restoring fouled membranes to a transmembrane pressure (TMP) near zero by increasing biogas sparging did not disrupt the biofilm's treatment performance, suggesting that microbes in the foulant layer were tightly adhered and did not significantly contribute to TMP. Dissolved methane oversaturation persisted without high TMP, implying that methanogenesis in the biofilm, rather than high TMP, was the primary driving force in methane oversaturation. The results describe an attractive operational strategy to improve treatment performance in low-temperature AnMBR by supporting syntrophy and methanogenesis in the membrane biofilm through controlled membrane fouling.

  11. Relationship Between COD and TOC of Typical Wastewaters in Jilin Province and Mechanism and Main Influencing Factors%吉林省典型废水COD与TOC的相关关系及其形成机制和影响因素

    Institute of Scientific and Technical Information of China (English)

    董德明; 宋兴; 花修艺; 袁懋; 梁建海; 郭志勇; 梁大鹏

    2012-01-01

    Chemical oxygen demand(COD) and total organic carbon(TOC) of typical wastewaters in Jilin Province were investigated. The possibilities of establishing linear regression equations were studied through analyzing relationship between COD contents and TOC contents of wastewaters. Based on this, influences of volatility and oxidization properties of organic compounds on relationship between COD contents and TOC contents of the wastewaters were discussed via analyzing organic compounds of some wastewaters. The mechanisms of the relationship of wastewaters were discussed. The results indicated that there were significant linear correlations between COD contents and TOC contents of all the samples of the typical wastewaters(a≤0. 050). The range of COD/TOC of all kinds of wastewaters were from 1. 711 to 12. 280. The relationship was mainly controlled by the composition of the wastewaters. Elemental composition of the typical organic pollutants in the wastewaters played a key role in determining the correlations between COD contents and TOC contents of the wastewaters. The volatilityand oxidization properties of the main organic pollutants in the waters also played important but divers roles in these correlations and the ratios of COD to TOC of the wastewater samples%为了解吉林省典型废水的化学需氧量(COD)与总有机碳(TOC)间的相关关系及其形成机制,在对吉林省典型废水的ρ(COD)与ρ(TOC)进行测定的基础上,分析了各类废水ρ(COD)与ρ(TOC)的相关关系,研究了其形成作用和有机组分的挥发性与可氧化特征对其的影响.结果表明:所研究废水水样的ρ(COD)与ρ(TOC)间均存在显著的线性相关关系(α≤0.050),各类废水ρ(COD)/ρ(TOC)为1.711~12.280;废水ρ(COD)与ρ(TOC)的相关关系主要由废水的有机化学成分决定,其中废水有机组分的元素组成起主导作用,有机组分的挥发性和可氧化特征对废水ρ(COD)与ρ(TOC)的相关性和比值均存在影响.

  12. Optimization of the determination of chemical oxygen demand in wastewaters.

    Science.gov (United States)

    Silva, Alexandra M E Viana da; Silva, Ricardo J N Bettencourt da; Camões, M Filomena G F C

    2011-08-12

    Chemical oxygen demand (COD) is one of the most relevant chemical parameters for the management of wastewater treatment facilities including the control of the quality of an effluent. The adequacy of decisions based on COD values relies on the quality of the measurements. Cost effective management of the minor sources of uncertainty can be applied to the analytical procedure without affecting measurement quality. This work presents a detailed assessment of the determination of COD values in wastewaters, according to ISO6060:1989 standard, which can support reduction of both measurement uncertainty and cost of analysis. This assessment includes the definition of the measurement traceability chain and the validation of the measurement procedure supported on sound and objective criteria. Detailed models of the measurement performance, including uncertainty, developed from the Differential Approach, were successfully validated by proficiency tests. The assumption of the measurement function linearity of the uncertainty propagation law was tested through the comparison with the numerical Kragten method. The gathered information supported the definition of strategies for measurement uncertainty or cost reduction. The developed models are available as electronic supplementary material, in an MS-Excel file, to be updated with the user's data.

  13. REMOVAL OF OIL AND GREASE FROM AN OIL REFINERY EFFLUENT

    Directory of Open Access Journals (Sweden)

    S.Naseri

    1997-06-01

    Full Text Available In this research performed during 1993-1994, the effluent of Behran Oil Refmery, in south of Tehran, which produces different types of industrial oil and greases, was studied and 3 methods of gravity separation, coagulation and flocculation and dissolved air flotation were investigated. In the first phase of the survey, the quality and quantity of the effluent were determined. This showed an average daily flow rate of 302 m3, pH 9.03, and average concentration of 314.84, 3330, 200, 1726 and 34.5 mg/l, respectively for oil, COD, SS, TS and furfural. In the second phase, the efficiency of abovementioned treatment methods were as follows: Applying gravity separation with the detention time of 180 mm, removal percentages for COD, SS and greases were 30.3%, 52.5% and 49.6%, respectively. Applying coagulation and flocculation following gravity separation different coagulants (alum, lime and ferric chloride were used and their treatment efficiencies were evaluated. Lime showed the highest efficiency of 64% and 85.4%, for grease and COD removal, respectively in pH 11. Dissolved air flotation (DAF, which was conducted in the pressure of 3 bars, showed average removal percentages of 9l.96% and 79.17%, for the oil and COD, respectively. So, this system may be chosen as the most efficient one in oil and grease removal producing an effluent which may be fed to a biological treatment unit to remove other pollutants such as ROD and COD.

  14. New type of canned cod gonads and liver pastes

    Directory of Open Access Journals (Sweden)

    Grokhovsky V. A.

    2016-09-01

    Full Text Available The urgency of rational way of processing the offal of the Gadidae family (liver and gonads for food purposes has been proved. The possibility of using the frozen gonads (milt and caviar and the liver of the cod in the human nutrition (especially for the people of elderly age has been researched. The frozen gonads with addition of fish liver are proven to be used for producing the canned foods with high quality level. The physical, chemical and microbiological characteristics of the product have been determined by the standardized methods. The quality level of canned foods has been obtained using the developed criteria of the objective evaluation of the quality. The specimens of the canned pastes produced from the frozen cod milt, caviar and liver using different compositions have been researched. Near-to-optimal composition of the new product has been defined. The quality level of canned food is 88.6 %. The commercial sterility of the canned food specimens prepared using the developed technology has been established. The chemical composition and the sensory characteristics of canned food have been researched. It has been established that protein content in the canned food is 12.9 %, fat content – 13.5 %, water content – 71.2 %, sodium chloride content – 1.3 %, carbohydrates content – 0.5 %. The product is the uniform, finely ground, evenly mixed mass with the presence of the separate caviar grains. The color of the paste is light-beige. The canned food has the tender consistency, pleasant taste and aroma. The energy value of the product is 678 kJ (162 kcal. Using the frozen cod caviar, milt and liver for producing the developed assortment of canned foods will make it possible to solve the problem of the complex processing of fish, and also to manufacture the canned food of high quality on the shore enterprises from the frozen fish offal (caviar, milt and liver all the year round.

  15. The removal of phenols from oily wastewater by chlorine dioxide

    OpenAIRE

    Hsu, Chung-Jung

    1988-01-01

    Treatability studies were performed on oily wastewaters produced by petroleum and canning industries. Chlorine dioxide was used for the removal of phenolic compounds from these oily wastewaters. Most of phenolic compounds can be destroyed by chlorine dioxide within 15 minutes if CI02-to-phenol ratios of higher than 5.0 are provided. Factors such as pH, temperature, and COD have little effect on phenol removal. The effectiveness of chlorine dioxide treatment depends critic...

  16. [Biological phosphorus removal in intermittent aerated biological filter].

    Science.gov (United States)

    Zeng, Long-Yun; Yang, Chun-Ping; Guo, Jun-Yuan; Luo, Sheng-Lian

    2012-01-01

    Under intermittent aerated and continuous fed operation where the biofilm system was subjected to alternated anaerobic/aerobic condition, the effect of influent volatile fatty acids (VFAs) concentrations, operation cycle and backwash on the biological phosphorus removal performance of the biofilter was studied. In the experiment, synthetic domestic wastewater was used, and the influent velocity was 5 L x h(-1) with gas versus liquid ratio of 8:1 and hydraulic retention time (HRT) of 1.3 h, resulting in average COD, ammonium and phosphorus load of 4.7, 0.41 and 0.095 g x (L x d) (-1) respectively. Results show that, (1) effective release and uptake of phosphorus was achieved in a operation cycle; (2) when influent VFAs was 100 mg x L(-1) (calculated by COD value) and operation cycle was 6 h the filter performed best in phosphorus removal, the phosphorus loading removal rate can be as much as 0.059 g x (L x d)(-1) at the aerated phase with those of COD and ammonium being 3.8 g x (L x d)(-1) and 0.28 g x (L x d)(-1) respectively, and with average effluent phosphorus, COD and ammonium concentrations being 1.8, 43.6 and 8.7 mg x L(-1), which shows nitrogen loss also happened; (3) the pause of backwash decreased the phosphorus removal performance rapidly with the removal efficiency lower than 40% in two days, but the consequent daily backwash operation gave a short improvement on the phosphorus removal, which disappeared in another two days. Thus, it is shown that biological phosphorus removal achieved with better phosphorus loading removal performance in the biofilter under intermittent aerated and continuous fed operation, and that sufficient and stable influent VFAs concentration, proper operation cycle, and more frequent backwash favored the performance.

  17. Paramedic Physical Demands Analysis

    Science.gov (United States)

    2014-07-01

    medical bags, cardiac monitor, stretcher, stair chair, etc.) were not standardized across services. As a result the total amount of equipment weight ...report describes the pushing/pulling, walking, and stair climbing demands as observed during the observation periods. Walking demands varied between the...standard deviation about the mean. .................................................................. 25 Figure 7 - The maximum weight (heaviest patient

  18. Wood supply and demand

    Science.gov (United States)

    Peter J. Ince; David B. McKeever

    2011-01-01

    At times in history, there have been concerns that demand for wood (timber) would be greater than the ability to supply it, but that concern has recently dissipated. The wood supply and demand situation has changed because of market transitions, economic downturns, and continued forest growth. This article provides a concise overview of this change as it relates to the...

  19. Eastern Baltic cod recruitment revisited—dynamics and impacting factors

    DEFF Research Database (Denmark)

    Köster, Fritz; Huwer, Bastian; Hinrichsen, Hans-Harald

    2016-01-01

    and casting doubts about the magnitude of the recent increase in recruitment. Earlier studies identified main factors impacting on cod reproductive success to be related to the loss of two out of three spawning areas in the 1980s caused by lack of major Baltic inflows with a concurrent reduction in salinity...... and oxygen. Other important factors include prey availability for first-feeding larvae, egg predation by sprat and herring and cannibalism on juveniles, all in one way or the other related to the prevailing hydrographic conditions. These factors cannot explain increased reproductive success in the last...

  20. Suitability of otolith microchemistry for stock separation of Baltic cod

    DEFF Research Database (Denmark)

    Heidemann, F; Marohn, L; Hinrichsen, HH

    2012-01-01

    differences between individuals from the eastern and the western Baltic Sea and between North Sea and Baltic Sea samples. Sr/Ca, Ba/Ca, Y/Ca, Mg/Ca, Zr/Ca and Mn/Ca ratios had the strongest discriminatory power. A further separation of individuals caught in 3 different spawning grounds of the eastern Baltic......, however, was not possible. Elemental compositions from the core regions of otoliths from young of the year cod caught in eastern and western Baltic Sea spawning grounds showed significant differences in Sr/Ca, Ba/Ca and Mg/Ca concentrations. Analyses of similarities again showed significant differences...

  1. REMOVAL OF PHOSPHATES FROM WATER BY PILLARED RECTORITE

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The presence of trace phosphates in treated wastewater from municipalities and industries is often responsible for eutrophication problems in lakes, rivers, and other water bodies. In this paper,we report the removal of PO43- from water by using a pillared rectorite that we synthesized recently. The results show that cross-linking can significantly increase the adsorbing capacity of Na-rectorite for phosphates. The pH, the concentrations of F, NH4+ and COD are main factors, which affect the results for pillared rectorite to adsorb phosphates from water. The OH-, and F- ions decrease the capacity to adsorb phosphates, while the COD and NH4+ ions increase it.

  2. Causality in demand

    DEFF Research Database (Denmark)

    Nielsen, Max; Jensen, Frank; Setälä, Jari;

    2011-01-01

    This article focuses on causality in demand. A methodology where causality is imposed and tested within an empirical co-integrated demand model, not prespecified, is suggested. The methodology allows different causality of different products within the same demand system. The methodology is applied...... to fish demand. On the German market for farmed trout and substitutes, it is found that supply sources, i.e. aquaculture and fishery, are not the only determinant of causality. Storing, tightness of management and aggregation level of integrated markets might also be important. The methodological...... implication is that more explicit focus on causality in demand analyses provides improved information. The results suggest that frozen trout forms part of a large European whitefish market, where prices of fresh trout are formed on a relatively separate market. Redfish is a substitute on both markets...

  3. DEVELOPMENT OF TECHNOLOGY FOR FISH CANNED PATE'S COD-FISH SPECIES

    OpenAIRE

    A. A. Efremova; L. K. Kuranova; O. A. Nikolaenko

    2014-01-01

    Summary. Fish and seafood play an important role in a balanced diet. The most reliable method of preservation is the production of canned fish. Cod fishery considered traditional objects of the North Basin, which catches in recent years stored at a consistently high level. They are represented, mainly cod, haddock, pollack, whiting. Lately there has been a tendency to increase yield loaves (polar bib). The aim of this work - the development of technology - canned pate's cod fish species with ...

  4. COD::CIF::Parser: an error-correcting CIF parser for the Perl language

    OpenAIRE

    Merkys, Andrius; Vaitkus, Antanas; Butkus, Justas; Okulič-Kazarinas, Mykolas; Kairys, Visvaldas; Gražulis, Saulius

    2016-01-01

    A syntax-correcting CIF parser, COD::CIF::Parser, is presented that can parse CIF 1.1 files and accurately report the position and the nature of the discovered syntactic problems. In addition, the parser is able to automatically fix the most common and the most obvious syntactic deficiencies of the input files. Bindings for Perl, C and Python programming environments are available. Based on COD::CIF::Parser, the cod-tools package for manipulating the CIFs in the Crystallogra...

  5. Using a Statistical Model to Examine the Effect of COD: SO42− Ratio, HRT and LA Concentration on Sulfate Reduction in an Anaerobic Sequencing Batch Reactor

    Directory of Open Access Journals (Sweden)

    Rajesh Singh

    2014-11-01

    Full Text Available Taguchi statistical design, an orthogonal array (OA method, was used to study the impact of the COD/SO42− ratio, hydraulic retention time (HRT and linoleic acid (LA concentration on sulfate (SO42− reduction in an anaerobic sequencing batch reactor using glucose as the electron donor. Based on the OA, optimum condition for maximum SO42− reduction was evaluated. Increasing the COD/SO42− ratio and HRT caused decreasing SO42− reduction while increased SO42− reduction was observed with increasing LA concentration (1 g L−1. In control (not fed LA cultures, higher SO42− reduction (87% ± 3% was observed at a low COD/SO42− ratio of 0.8. This indicates that increasing SO42− reduction was observed at increasing SO42− loading rates. In general, results from this study reveal that limiting the substrate concentration with high SO42− levels (low COD/SO42− ratio favors high SO42− removal. Surface plots were used to evaluate the significant interactions between the experimental factors. Accuracy of the model was verified using an analysis of residuals. Optimum conditions for maximum SO42− reduction (97.61% were observed at a COD/SO42− ratio of 0.8 (level 1, 12 h HRT (level 1 together with 1000 mg L−1 LA addition (level 3. In general, the Taguchi OA provided a useful approach for predicting the percent SO42− reduction in inhibited mixed anaerobic cultures within the factor levels investigated.

  6. Biological phosphorus removal during high-rate, low-temperature, anaerobic digestion of wastewater

    Directory of Open Access Journals (Sweden)

    Ciara eKeating

    2016-03-01

    Full Text Available We report, for the first time, extensive biologically-mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD. A hybrid sludge bed/fixed-film (packed pumice stone reactor was employed for low-temperature (12°C anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis revealed the accumulation of elemental phosphorus (~2% within the sludge bed and fixed-film biofilms. 4’, 6-diamidino-2-phenylindole (DAPI staining indicated phosphorus accumulation was biological in nature and mediated through the formation of intracellular inorganic polyphosphate (polyP granules within these biofilms. DAPI staining further indicated that polyP accumulation was rarely associated with free cells. Efficient and consistent chemical oxygen demand (COD removal was recorded, throughout the 732-day trial, at applied organic loading rates between 0.4-1.5 kg COD m-3 d-1 and hydraulic retention times of 8-24 hours, while phosphate removal efficiency ranged from 28-78% on average per phase. Analysis of protein hydrolysis kinetics and the methanogenic activity profiles of the biomass revealed the development, at 12˚C, of active hydrolytic and methanogenic populations. Temporal microbial changes were monitored using Illumina Miseq analysis of bacterial and archaeal 16S rRNA gene sequences. The dominant bacterial phyla present in the biomass at the conclusion of the trial were the Proteobacteria and Firmicutes and the dominant archaeal genus was Methanosaeta. Trichococcus and Flavobacterium populations, previously associated with low temperature protein degradation, developed in the reactor biomass. The presence of previously characterised polyphosphate accumulating organisms (PAOs such as Rhodocyclus, Chromatiales, Actinobacter and Acinetobacter was

  7. Biological Phosphorus Removal During High-Rate, Low-Temperature, Anaerobic Digestion of Wastewater.

    Science.gov (United States)

    Keating, Ciara; Chin, Jason P; Hughes, Dermot; Manesiotis, Panagiotis; Cysneiros, Denise; Mahony, Therese; Smith, Cindy J; McGrath, John W; O'Flaherty, Vincent

    2016-01-01

    We report, for the first time, extensive biologically mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12°C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis revealed the accumulation of elemental phosphorus (∼2%) within the sludge bed and fixed-film biofilms. 4', 6-diamidino-2-phenylindole (DAPI) staining indicated phosphorus accumulation was biological in nature and mediated through the formation of intracellular inorganic polyphosphate (polyP) granules within these biofilms. DAPI staining further indicated that polyP accumulation was rarely associated with free cells. Efficient and consistent chemical oxygen demand (COD) removal was recorded, throughout the 732-day trial, at applied organic loading rates between 0.4 and 1.5 kg COD m(-3) d(-1) and hydraulic retention times of 8-24 h, while phosphate removal efficiency ranged from 28 to 78% on average per phase. Analysis of protein hydrolysis kinetics and the methanogenic activity profiles of the biomass revealed the development, at 12°C, of active hydrolytic and methanogenic populations. Temporal microbial changes were monitored using Illumina MiSeq analysis of bacterial and archaeal 16S rRNA gene sequences. The dominant bacterial phyla present in the biomass at the conclusion of the trial were the Proteobacteria and Firmicutes and the dominant archaeal genus was Methanosaeta. Trichococcus and Flavobacterium populations, previously associated with low temperature protein degradation, developed in the reactor biomass. The presence of previously characterized polyphosphate accumulating organisms (PAOs) such as Rhodocyclus, Chromatiales, Actinobacter, and Acinetobacter was recorded

  8. THE "CHEMICAL OXYGEN DEMAND / TOTAL VOLATILE ACIDS" RATIO AS AN ANAEROBIC TREATABILITY INDICATOR FOR LANDFILL LEACHATES

    Directory of Open Access Journals (Sweden)

    R. C. Contrera

    2015-03-01

    Full Text Available Abstract In some operational circumstances a fast evaluation of landfill leachate anaerobic treatability is necessary, and neither Biochemical Methane Potential nor BOD/COD ratio are fast enough. Looking for a fast indicator, this work evaluated the anaerobic treatability of landfill leachate from São Carlos-SP (Brazil in a pilot scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR. The experiment was conducted at ambient temperature in the landfill area. After the acclimation, at a second stage of operation, the AnSBBR presented efficiency above 70%, in terms of COD removal, utilizing landfill leachate without water dilution, with an inlet COD of about 11,000 mg.L-1, a TVA/COD ratio of approximately 0.6 and reaction time equal to 7 days. To evaluate the landfill leachate biodegradability variation over time, temporal profiles of concentration were performed in the AnSBBR. The landfill leachate anaerobic biodegradability was verified to have a direct and strong relationship to the TVA/COD ratio. For a TVA/CODTotal ratio lower than 0.20, the biodegradability was considered low, for ratios between 0.20 and 0.40 it was considered medium, and above 0.40 it was considered high.

  9. Quantum dots assisted photocatalysis for the chemiluminometric determination of chemical oxygen demand using a single interface flow system

    Energy Technology Data Exchange (ETDEWEB)

    Silvestre, Cristina I.C.; Frigerio, Christian [Requimte, Department of Chemistry, Faculty of Pharmacy, Porto University, Rua Anibal Cunha 164, 4099-030, Porto (Portugal); Santos, Joao L.M., E-mail: joaolms@ff.up.pt [Requimte, Department of Chemistry, Faculty of Pharmacy, Porto University, Rua Anibal Cunha 164, 4099-030, Porto (Portugal); Lima, Jose L.F.C. [Requimte, Department of Chemistry, Faculty of Pharmacy, Porto University, Rua Anibal Cunha 164, 4099-030, Porto (Portugal)

    2011-08-12

    Highlights: {yields} A novel flow method for the determination of chemical oxygen demand is proposed. {yields} CdTe nanocrystals are irradiated with UV light to generate strong oxidizing species. {yields} Reactive species promote a fast catalytic degradation of organic matter. {yields} Luminol is used as a chemiluminescence probe for indirect COD assessment. {yields} A single interface flow system was implemented to automate the assays. - Abstract: A novel flow method for the determination of chemical oxygen demand (COD) is proposed in this work. It relies on the combination of a fully automated single interface flow system, an on-line UV photocatalytic unit and quantum dot (QD) nanotechnology. The developed approach takes advantage of CdTe nanocrystals capacity to generate strong oxidizing species upon irradiation with UV light, which fostered a fast catalytic degradation of the organic compounds. Luminol was used as a chemiluminescence (CL) probe for indirect COD assessment, since it is easily oxidized by the QD generated species yielding a strong CL emission that is quenched in the presence of the organic matter. The proposed methodology allowed the determination of COD concentrations between 1 and 35 mg L{sup -1}, with good precision (R.S.D. < 1.1%, n = 3) and a sampling frequency of about 33 h{sup -1}. The procedure was applied to the determination of COD in wastewater certified reference materials and the obtained results showed an excellent agreement with the certified values.

  10. Characterization and removal of specific organic constituents in an UASB-trickling-filter system treating domestic wastewater.

    Science.gov (United States)

    Pontes, Patrícia Procópio; Chernicharo, Carlos Augusto de Lemos

    2011-01-01

    This paper presents the characterization of specific organic constituents (carbohydrates, proteins and lipids) in raw sewage and in the anaerobic and aerobic effluents of a demo-scale (500 inhabitants) UASB- trickling-filter system. The evaluation of such parameters was carried out for two operating conditions, either without sludge recirculation (experiment I) from the trickling filter to the UASB reactor or with sludge recirculation (experiment II), for sludge thickening and stabilization, in the anaerobic reactor. The results showed that the contribution of acetic acid, carbohydrates, proteins and lipids amounted for approximately 70% of the total COD fed to the UASB during experiment I, whereas during experiment II these constituents amounted for only around 40% of the total COD. Although very high BOD and COD overall removal efficiencies were observed for the treatment system (around 90% and 80%, respectively), it was possible to infer that these efficiencies were mainly related to the removal of carbohydrates and lipids (around 80% removal), and of other non-identified constituents. The removal of proteins was much lower (around 50% removal), and the relative contribution of proteins to the total COD increased along the treatment course, being responsible for most of the residual COD of the treatment units. In the present system configuration, the UASB reactor played a major role in the removal of carbohydrates, whereas the trickling filter was very effective in the removal of lipids. The return of aerobic sludge for thickening and stabilization in the UASB reactor did not affect its performance.

  11. Warm, windy winters drive cod north and homing of spawners keeps them there

    DEFF Research Database (Denmark)

    Rindorf, Anna; Lewy, Peter

    2006-01-01

    and larval phases of cod led to a northward shift in the distribution of juvenile North Sea cod the following year. A concomitant northern shift of mature fish around the time of spawning was linked directly to a tendency for northerly distributed juveniles to remain northerly throughout their life...... of older age groups. Unless a series of cold and calm years combined with a reduced mortality in the southern areas allows a southern spawning population to rebuild, the cod stock is unlikely to return to its previous area of distribution. Furthermore, protecting adult cod mainly in northern areas...

  12. Cod Fractions - Methods of Measurement and Use in Wastewater Treatment Technology

    Science.gov (United States)

    Myszograj, Sylwia; Płuciennik-Koropczuk, Ewelina; Jakubaszek, Anita

    2017-03-01

    The paper presents the results of studies concerning the designation of COD fraction in raw wastewater. The research was conducted in four municipal mechanical-biological sewage treatment plants and one industrial sewage treatment plant. The following fractions of COD were determined: non-biodegradable (inert) soluble SI, biodegradable soluble fraction SS, particulate slowly degradable XS and particulate non-biodegradable XI. The methodology for determining the COD fraction was based on the ATV-A131 guidelines and Łomotowski-Szpindor methodology. The real concentration of fractions in raw wastewater and the percentage of each fraction in total COD are different from data reported in the literature.

  13. Cod Fractions - Methods of Measurement and Use in Wastewater Treatment Technology

    Directory of Open Access Journals (Sweden)

    Myszograj Sylwia

    2017-03-01

    Full Text Available The paper presents the results of studies concerning the designation of COD fraction in raw wastewater. The research was conducted in four municipal mechanical-biological sewage treatment plants and one industrial sewage treatment plant. The following fractions of COD were determined: non-biodegradable (inert soluble SI, biodegradable soluble fraction SS, particulate slowly degradable XS and particulate non-biodegradable XI. The methodology for determining the COD fraction was based on the ATV-A131 guidelines and Łomotowski-Szpindor methodology. The real concentration of fractions in raw wastewater and the percentage of each fraction in total COD are different from data reported in the literature.

  14. Nutritional condition and vertical distribution of Baltic cod larvae

    DEFF Research Database (Denmark)

    Grønkjær, P.; Clemmesen, C.; St. John, Michael

    1997-01-01

    Newly hatched Baltic cod Gadus morhua larvae are typically found at depths >60 m. This is a region of low light and prey availability, hence generating the hypothesis that larvae have to migrate from hatching depth to the surface layer to avoid starvation and improve their nutritional condition....... To lest this hypothesis, Baltic cod larvae were sampled during the spawning seasons of 1994 and 1995 with depth-resolving multiple opening/closing nets. Each larva was aged by otolith readings and its RNA/DNA ratio was determined as a measure of nutritional condition. The RNA/DNA ratios of these larvae...... aged 2-25 days (median 10 days) ranged from 0.4 to 6.2, corresponding to levels exhibited by starving and fast growing larvae in laboratory calibration studies (starvation, protein growth rate, G(pi)=-12.2% day(-1); fast-growing larvae, G(pi)=14.1% day(-1)) respectively. Seventy per cent of the field...

  15. Developing Baltic cod recruitment models I : Resolving spatial and temporal dynamics of spawning stock and recruitment for cod, herring, and sprat

    DEFF Research Database (Denmark)

    Köster, Fritz; Möllmann, C.; Neuenfeldt, Stefan

    2001-01-01

    -disaggregated multispecies virtual population analyses (MSVPA) were performed for interacting species cod, herring (Clupea harengus), and sprat in the different subdivisions of the Central Baltic. The MSVPA runs revealed distinct spatial trends in population abundance, spawning biomass, recruitment, and predation......-induced mortality. Results, when evaluated with respect to trends in population sizes from research surveys, were similar for the cod and sprat stocks but different for herring. Horizontal distributions from MSVPA runs and research surveys indicate that cod and sprat undergo migrations between basins during...

  16. Tick Removal

    Science.gov (United States)

    ... ticks Tickborne diseases abroad Borrelia miyamotoi Borrelia mayonii Tick Removal Recommend on Facebook Tweet Share Compartir If ... a tick quite effectively. How to remove a tick Use fine-tipped tweezers to grasp the tick ...

  17. Effect of powdered activated carbon technology on short-cut nitrogen removal for coal gasification wastewater.

    Science.gov (United States)

    Zhao, Qian; Han, Hongjun; Xu, Chunyan; Zhuang, Haifeng; Fang, Fang; Zhang, Linghan

    2013-08-01

    A combined process consisting of a powdered activated carbon technology (PACT) and short-cut biological nitrogen removal reactor (SBNR) was developed to enhance the removal efficiency of the total nitrogen (TN) from the effluent of an upflow anaerobic sludge bed (UASB) reactor, which was used to treat coal gasification wastewater (CGW). The SBNR performance was improved with the increasing of COD and TP removal efficiency via PACT. The average removal efficiencies of COD and TP in PACT were respectively 85.80% and 90.30%. Meanwhile, the NH3-N to NO2-N conversion rate was achieved 86.89% in SBNR and the total nitrogen (TN) removal efficiency was 75.54%. In contrast, the AOB in SBNR was significantly inhibited without PACT or with poor performance of PACT in advance, which rendered the removal of TN. Furthermore, PAC was demonstrated to remove some refractory compounds, which therefore improved the biodegradability of the coal gasification wastewater.

  18. Atlantic cod (Gadus morhua hemoglobin genes: multiplicity and polymorphism

    Directory of Open Access Journals (Sweden)

    Gamperl A Kurt

    2009-09-01

    Full Text Available Abstract Background Hemoglobin (Hb polymorphism, assessed by protein gel electrophoresis, has been used almost exclusively to characterize the genetic structure of Atlantic cod (Gadus morhua populations and to establish correlations with phenotypic traits such as Hb oxygen binding capacity, temperature tolerance and growth characteristics. The genetic system used to explain the results of gel electrophoresis entails the presence of one polymorphic locus with two major alleles (HbI-1; HbI-2. However, vertebrates have more than one gene encoding Hbs and recent studies have reported that more than one Hb gene is present in Atlantic cod. These observations prompted us to re-evaluate the number of Hb genes expressed in Atlantic cod, and to perform an in depth search for polymorphisms that might produce relevant phenotypes for breeding programs. Results Analysis of Expressed Sequence Tags (ESTs led to the identification of nine distinct Hb transcripts; four corresponding to the α Hb gene family and five to the β Hb gene family. To gain insights about the Hb genes encoding these transcripts, genomic sequence data was generated from heterozygous (HbI-1/2 parents and fifteen progeny; five of each HbI type, i.e., HbI-1/1, HbI-1/2 and HbI-2/2. β Hb genes displayed more polymorphism than α Hb genes. Two major allele types (β1A and β1B that differ by two linked non-synonymous substitutions (Met55Val and Lys62Ala were found in the β1 Hb gene, and the distribution of these β1A and β1B alleles among individuals was congruent with that of the HbI-1 and HbI-2 alleles determined by protein gel electrophoresis. RT-PCR and Q-PCR analysis of the nine Hb genes indicates that all genes are expressed in adult fish, but their level of expression varies greatly; higher expression of almost all Hb genes was found in individuals displaying the HbI-2/2 electrophoretic type. Conclusion This study indicates that more Hb genes are present and expressed in adult

  19. Price elasticity of demand for psychiatric consultation in a Nigerian ...

    African Journals Online (AJOL)

    African Health Sciences Vol 16 Issue 4, December, 2016. Abstract: Objective: This paper addresses price elasticity of demand (PED) in a region ... Accordingly, such commodities ... In low- and middle-income countries removing or reduc-.

  20. Translating removal efficiencies into operational performance indices of wastewater treatment plants.

    Science.gov (United States)

    Silva, Catarina; Quadros, Sílvia; Ramalho, Pedro; Alegre, Helena; Rosa, Maria João

    2014-06-15

    Removal efficiencies are often used to assess the performance of a single or a group of unit operations/processes (UOPs) of a wastewater treatment plant (WWTP). However, depending on the influent concentration (Cin), the same efficiency of removal (Er) may be insufficient or excessive to achieve the UOP or WWTP effluent quality requirements, expressed by concentration limit values (LVs). This paper proposes performance indices (PXs), Er-based, as new metrics for benchmarking, i.e. for assessing and improving the performance of each UOP or treatment step and ultimately of the WWTP as a multi-barrier system, and comprehensively describes the stepwise method of translating Ers into PXs. PXs are dimensionless and vary between 0 and 300 to define three performance levels: unsatisfactory (0-100), acceptable (100-200) and good (200-300) performance. The method developed takes into consideration Cin and LV, and the reference values for judging the performance are given from Er-Cin typical ranges and Er vs. Cin model curves, LV based and field data based. The general equations of the Er model curves are derived. A set of six curves is calibrated for TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) removal by primary sedimentation and activated sludge systems (carbon or combined carbon and nutrients removal), using 5-year (2006-2010) field data from five Portuguese WWTPs. A statistical analysis of the PX results is additionally proposed to assess treatment reliability. The new method is applied in two WWTPs and the PX results are compared with those of conventional measures - Er and performance indicators (PIs). The results demonstrate that, whereas a simplistic Er-driven or PI-driven management of the WWTPs shows limitations, the developed PXs are adequate measures for benchmarking removal efficiencies towards WWTP reliability and sustainability. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Coordination of Energy Efficiency and Demand Response

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, Charles; Reid, Michael; Levy, Roger; Silverstein, Alison

    2010-01-29

    This paper reviews the relationship between energy efficiency and demand response and discusses approaches and barriers to coordinating energy efficiency and demand response. The paper is intended to support the 10 implementation goals of the National Action Plan for Energy Efficiency's Vision to achieve all cost-effective energy efficiency by 2025. Improving energy efficiency in our homes, businesses, schools, governments, and industries - which consume more than 70 percent of the nation's natural gas and electricity - is one of the most constructive, cost-effective ways to address the challenges of high energy prices, energy security and independence, air pollution, and global climate change. While energy efficiency is an increasingly prominent component of efforts to supply affordable, reliable, secure, and clean electric power, demand response is becoming a valuable tool in utility and regional resource plans. The Federal Energy Regulatory Commission (FERC) estimated the contribution from existing U.S. demand response resources at about 41,000 megawatts (MW), about 5.8 percent of 2008 summer peak demand (FERC, 2008). Moreover, FERC recently estimated nationwide achievable demand response potential at 138,000 MW (14 percent of peak demand) by 2019 (FERC, 2009).2 A recent Electric Power Research Institute study estimates that 'the combination of demand response and energy efficiency programs has the potential to reduce non-coincident summer peak demand by 157 GW' by 2030, or 14-20 percent below projected levels (EPRI, 2009a). This paper supports the Action Plan's effort to coordinate energy efficiency and demand response programs to maximize value to customers. For information on the full suite of policy and programmatic options for removing barriers to energy efficiency, see the Vision for 2025 and the various other Action Plan papers and guides available at www.epa.gov/eeactionplan.

  2. Study on the Transport of COD in the Sea Area Around Maidao off Qingdao Coast Using Data Assimilation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A two-layer pollutant advection-diffusion model is built to investigate the pollutant transport in the sea area around Maidao off Qingdao coast. An adjoint data assimilation technique is applied to estimate the optimal values of the model parameters. The experimental results on the initial field of pollutant indicate that the distribution of Chemical Oxygen Demand (COD) concentration is sensitive to the horizontal eddy diffusivity. An appropriate value of horizontal eddy diffusivity is necessary in order to depict the influence of the initial field precisely, and it is also essential to the simulation of the advection-diffusion process of the pollutant. By inversion of the model parameters and optimization of the initial COD concentrations, the simulation results are improved significantly. The cost function is reduced to 40% of its first step value. The average misfit between the model outputs and the observations in the upper layer decreases from 0.46 to 0.25 mgL-1, and that in the lower layer decreases from 0.22 to 0.14mgL-1.

  3. Non-contact assessment of COD and turbidity concentrations in water using diffuse reflectance UV-Vis spectroscopy.

    Science.gov (United States)

    Agustsson, Jon; Akermann, Oliver; Barry, D Andrew; Rossi, Luca

    2014-08-01

    Water contamination is an important environmental concern underlining the need for reliable real-time information on contaminant concentrations in natural waters. Here, a new non-contact UV-Vis spectroscopic approach for monitoring contaminants in water, and especially wastewater, is proposed. Diffuse reflectance UV-Vis spectroscopy was applied to measure simultaneously the chemical oxygen demand (COD) and turbidity (TUR) concentrations in water. The measurements were carried out in the wavelength range from 200-1100 nm. The measured spectra were analysed using partial-least-squares (PLS) regression. The correlation coefficient between the measured and the reference concentrations of COD and TUR in the water samples were R(2) = 0.85 and 0.96, respectively. These results highlight the potential of non-contact UV-Vis spectroscopy for the assessment of water contamination. A system built on the concept would be able to monitor wastewater pollution continuously, without the need for laborious sample collection and subsequent laboratory analysis. Furthermore, since no parts of the system are in contact with the wastewater stream the need for maintenance is minimised.

  4. Domestic Demand Will Work

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China can invigorate its economy by expanding domestic demand and boosting consumption chinese bankers are preparing to set up finance companies that provide consumer loans in major cities like Beijing and Shanghai.

  5. Intelligent energy demand forecasting

    CERN Document Server

    Hong, Wei-Chiang

    2013-01-01

    This book offers approaches and methods to calculate optimal electric energy allocation, using evolutionary algorithms and intelligent analytical tools to improve the accuracy of demand forecasting. Focuses on improving the drawbacks of existing algorithms.

  6. Household fuel demand analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cohn, S.; Hirst, E.; Jackson, J.

    1976-01-01

    This study develops econometric models of residential demands for electricity, natural gas, and petroleum products. Fuel demands per household are estimated as functions of fuel prices, per capita income, heating degree days, and mean July temperature. Cross-sectional models are developed using a large data base containing observations for each state and year from 1951 through 1974. Long-run own-price elasticities for all three fuels are greater than unity with natural gas showing the greatest sensitivity to own-price changes. Cross-price elasticities are all less than unity except for the elasticity of demand for oil with respect to the price of gas (which is even larger than the own-price elasticity of demand for oil). The models show considerable stabiity with respect to own-price elasticities but much instability with respect to the cross-price and income elasticities.

  7. Impact of Energy Demands

    Science.gov (United States)

    Cambel, Ali B.

    1970-01-01

    The types of pollutants associated with the process of power production are identified. A nine-point proposal is presented on the ways the increase in power demands might be achieved with the minimum threat to the environment. (PR)

  8. KEMAMPUAN SISTEM SARINGAN PASIR-TANAMAN MENURUNKAN NILAI BOD DAN COD AIR TERCEMAR LIMBAH PENCELUPAN

    Directory of Open Access Journals (Sweden)

    I W. Budiarsa Suyasa

    2012-11-01

    Full Text Available Colored of clothes has developed as concentrated in Denpasar area. The process has a negativeeffect because of waste, the resulting organic toxicants and heavy metal into aquatic system. The effect ofthe pollution including the river, well water and organism that live there. The research of bioremedialeffectiveness of herb-sand treatment system on laboratory simulation were studied in Denpasar, from June2004 to September 2004.For laboratory simulation, the plants were cultured in 25 cm sand bed, in between 5 cm palmfiber ofwhich were in between 10 cm pumicestone for the top and 5 cm gravel for the bottom with surface area of 25x 50 cm2.The result of treatment system showed that effective for decrease biological oxygen demandcompared to those of chemical oxygen demand parameters. The treatment system reduced significantly BODlevel respectively to 13,15 for 3 days, 11,19 for 10 days and 5,79 for 20 days with 85,55 – 93,63 effectively.While COD level respectively to 76,68 for 3 days, 61,38 for 10 days and 58,57 for 20 days with 42,78 – 56,50effectively. Time of treatment for 3, 10 and 20 days showed a little increase of pH from 6,87 to 7,00.

  9. PENURUNAN COD, TSS DAN TOTAL FOSFAT PADA SEPTIC TANK LIMBAH MATARAM CITRA SEMBADA CATERING DENGAN MENGGUNAKAN WASTEWATER GARDEN (Degradation of COD, TSS and Total Phosphate in Septic Tank Wastewater of Mataram Citra Sembada Catering Using Wastewater

    Directory of Open Access Journals (Sweden)

    Dradjat Suhardjo

    2008-07-01

    Full Text Available ABSTRAK  Sumber limbah berasal dari septictank industri restauran (catering Citra Sembada Catering, termasuk dalam kategori limbah domestik. Limbah tersebut banyak mengandung komponen yang tidak diinginkan bila dibuang ke badan air. Konsentrasi limbah yang masih di atas baku mutu, di antaranya akan memunculkan masalah pencemaran. Reaktor Wastewater Garden yang menggunakan krikil (0,5Cm-1cm dan 6 jenis tanaman yaitu : melati air (Echinodoras paleafias, Cyperus (Cyperus, Futoi (Hippochaetes lymnenalis, Pisang air (Typhonodorum indleyanum, Pickerel rush (Pontedoria cordata, Cattail (Typha latifulia. Penelitian ini bertujuan untuk mengetahui tingkat efektivitas reaktor Wastewater Garden, apabila digunakan untuk menurunkan konsentrasi Chemical Oxygen Demand (COD, Total Suspended Solid (TSS dan Fosfat Total sebagai faktor pencemar pada limbah industri restauran (Citra Sembada Catering yang tertampung pada septictank. Penelitian dilakukan dengan menggunakan reaktor Wastewater Garden dengan sistem batch dan dimensi reaktor lm x 0.5m x lm. Zona air limbah 75 cm, dan zona substrat atau krikil 80 cm, akar tanaman ditanam sedalam l0-15 cm. Metode penelitian yang digunakan berdasarkan SNI, di mana COD mengacu pada SNI 06-6989.2-2004 metode refluks tertutup secara spektrofotometri, TSS mengacu pada SK SNI M-03-1990-F metode pengujian secara gravimetri dan Fosfat total mengacu pada SNI M-52-1990-03 metode asam askorbat dengan alat spektrofotometer. Penelitian ini dilakukan selama 12 hari di mana setiap 3 hari sampel diambil pada outlel kemudian dianalisis. Berdasarkan hasil penelitian ini, diperoleh bahwa penggunaan wastewater garden pada limbah cair Mataram Citra Sembada Catering dapat menurunkan COD dengan efektivitas optimum 40,81% pada hari ke-6, penurunan TSS 89,l2% pada efektifitas optirnum hari ke-12 dan penurunan fosfat total dengan efektivitas optimum pada hari ke-6 yaitu sebesar 99,73 %. Tanaman dapat hidup dengan subur.   ABSTRACT  Wastewater

  10. Improvement of NOM Removal from Water Resources by Modifying the Coagulation Process

    Directory of Open Access Journals (Sweden)

    F Vaezi, A Mohagheghian, J Nouri, MR Eshraghian, A Ghasri

    2005-01-01

    Full Text Available As a result of the regulations on DBPs, interest in NOM removal is increasing and many water treatment plants in developed countries have started to measure the concentration of TOC in their finished waters. Promulgation of the rules will substantially increase these efforts in other countries too. Since the cost of TOC (and DBPs determination was high, it was decided to study the traditional analysis of COD as a surrogate measure to detect the organic constituents in raw water and the extent to which optimized coagulation with ferric chloride can increase COD removal. The two water samples studied belonged to Karaj and Jajrood Rivers. For both samples the observed values of COD removal by coagulation at lower pH (about 1-1.5 pH values less than the regular pH were about 85-95 percent without making water turbidity unacceptable. In order to determine the effects of organic content on coagulation, synthetic samples were also prepared with much higher COD values. Again, considerable increases in COD removal have been observed for most of these samples only by decreasing 0.5-2 pH value. The results indicated that a modified coagulation process without need to much increasing the amount of coagulant can be developed for these water samples.

  11. Evaluation of nitrate removal effect on groundwater using artificial neural networks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Considering the non-linear, complex and multivariable process of biological denitrification, an activated sludge process was introduced to remove nitrate in groundwater with the aid of artificial neural networks(ANN) to evaluate the nitrate removal effect. The parameters such as COD, NH3-N, NO3--N, NO2--N, MLSS,DO, etc. , were used for input nodes, and COD , NH3 -N , NO3--N , NO2--N were selected for output nodes. Experimental ANN training results show that ANN was able to predict the output water quality parameters very well. Most of relative errors of NO3--N and COD were in the range of ± 10% and ±5% respectively. The results predicted by ANN model of nitrate removal in groundwater produced good agreement with the experimental data. Though ANN model can optimize effect of the whole system, it cannot replace the water treatment process.

  12. Integration of photocatalysis and biological treatment for azo dye removal--application to AR183.

    Science.gov (United States)

    Chebli, Derradji; Fourcade, Florence; Brosillon, Stephan; Nacef, Saci; Amrane, Abdeltif

    2011-04-01

    The feasibility of coupling photocatalysis with biological treatment to treat effluents containing azo dyes was examined in this work. With this aim, the degradation of Acid Red 183 was investigated. The very low biodegradability of AR183 was confirmed beforehand by measuring the biological oxygen demand (BOD5). Photocatalysis experiments were carried out in a closed-loop step photoreactor. The reactor walls were covered by TiO2 catalyst coated on non-woven paper, and the effluent flowed over the photocatalyst as a thin falling film. The removal of the dye was 82.7% after 4 h, and a quasi-complete decolorization (98.5%) was obtained for 10 h of irradiation (initial concentration 100 mg L(-1)). The decrease in concentration followed pseudo-first-order kinetics, with a constant k of 0.47 h(-1). Mineralization and oxidation yields were 80% and 75%, respectively, after 10 h of pretreatment. Therefore, even if target compound oxidation occurs (COD removal), indicating a modification to the chemical structure, the concomitant high mineralization was not in favour of subsequent microbial growth. The BOD5 measurement confirmed the non-biodegradability of the irradiated solution, which remained toxic since the EC50 decreased from 35 to 3 mg L(-1). The proposed integrated process appeared, therefore, to be not relevant for the treatment of AR183. However, this result should be confirmed for other azo dyes.

  13. Evaluation of Heavy Metal Removal from Wastewater in a Modified Packed Bed Biofilm Reactor.

    Directory of Open Access Journals (Sweden)

    Shohreh Azizi

    Full Text Available For the effective application of a modified packed bed biofilm reactor (PBBR in wastewater industrial practice, it is essential to distinguish the tolerance of the system for heavy metals removal. The industrial contamination of wastewater from various sources (e.g. Zn, Cu, Cd and Ni was studied to assess the impacts on a PBBR. This biological system was examined by evaluating the tolerance of different strengths of composite heavy metals at the optimum hydraulic retention time (HRT of 2 hours. The heavy metal content of the wastewater outlet stream was then compared to the source material. Different biomass concentrations in the reactor were assessed. The results show that the system can efficiently treat 20 (mg/l concentrations of combined heavy metals at an optimum HRT condition (2 hours, while above this strength there should be a substantially negative impact on treatment efficiency. Average organic reduction, in terms of the chemical oxygen demand (COD of the system, is reduced above the tolerance limits for heavy metals as mentioned above. The PBBR biological system, in the presence of high surface area carrier media and a high microbial population to the tune of 10 000 (mg/l, is capable of removing the industrial contamination in wastewater.

  14. Evaluation of Heavy Metal Removal from Wastewater in a Modified Packed Bed Biofilm Reactor.

    Science.gov (United States)

    Azizi, Shohreh; Kamika, Ilunga; Tekere, Memory

    2016-01-01

    For the effective application of a modified packed bed biofilm reactor (PBBR) in wastewater industrial practice, it is essential to distinguish the tolerance of the system for heavy metals removal. The industrial contamination of wastewater from various sources (e.g. Zn, Cu, Cd and Ni) was studied to assess the impacts on a PBBR. This biological system was examined by evaluating the tolerance of different strengths of composite heavy metals at the optimum hydraulic retention time (HRT) of 2 hours. The heavy metal content of the wastewater outlet stream was then compared to the source material. Different biomass concentrations in the reactor were assessed. The results show that the system can efficiently treat 20 (mg/l) concentrations of combined heavy metals at an optimum HRT condition (2 hours), while above this strength there should be a substantially negative impact on treatment efficiency. Average organic reduction, in terms of the chemical oxygen demand (COD) of the system, is reduced above the tolerance limits for heavy metals as mentioned above. The PBBR biological system, in the presence of high surface area carrier media and a high microbial population to the tune of 10 000 (mg/l), is capable of removing the industrial contamination in wastewater.

  15. 4-chlorophenol removal from water using graphite and graphene oxides as photocatalysts.

    Science.gov (United States)

    Bustos-Ramírez, Karina; Barrera-Díaz, Carlos Eduardo; De Icaza-Herrera, Miguel; Martínez-Hernández, Ana Laura; Natividad-Rangel, Reyna; Velasco-Santos, Carlos

    2015-01-01

    Graphite and graphene oxides have been studied amply in the last decade, due to their diverse properties and possible applications. Recently, their functionality as photocatalytic materials in water splitting was reported. Research in these materials is increasing due to their band gap values around 1.8-4 eV, and therefore, these are comparable with other photocatalysts currently used in heterogeneous photocatalytic processes. Thus, this research reports the photocatalytic effectiveness of graphite oxide (GO) and graphene oxide (GEO) in the degradation of 4-chlorophenol (4-CP) in water. Under the conditions defined for this research, 92 and 97% of 4-CP were degraded with GO and GEO respectively, also 97% of total organic carbon was removed. In addition, by-products of 4-CP that produce a yellow solution obtained only using photolysis are eliminated by photocatalyst process with GO and GEO. The degradation of 4-CP was monitored by UV-Vis spectroscopy, High Performance Liquid Chromatography (HPLC) and Chemical Oxygen Demand (COD). Thus, photocatalytic activity to remove 4-CP from water employing GO and GEO without doping is successfully showed, and therefore, a new gate in research for these materials is opened.

  16. Upgrading coagulation with hollow-fibre nanofiltration for improved organic matter removal during surface water treatment.

    Science.gov (United States)

    Köhler, Stephan J; Lavonen, Elin; Keucken, Alexander; Schmitt-Kopplin, Philippe; Spanjer, Tom; Persson, Kenneth

    2016-02-01

    Rising organic matter concentrations in surface waters in many Nordic countries require current drinking water treatment processes to be adapted. Accordingly, the use of a novel nanofiltration (NF) membrane was studied during a nine month period in pilot scale at a large drinking water treatment plant in Stockholm, Sweden. A chemically resistant hollow-fibre NF membrane was fed with full scale process water from a rapid sand filter after aluminum sulfate coagulation. The combined coagulation and NF process removed more than 90% of the incoming lake water dissolved organic carbon (DOC) (8.7 mg C L(-1)), and 96% of the absorbance at 254 nm (A254) (0.28 cm(-1) incoming absorbance). Including granulated active carbon GAC) filter, the complete pilot plant treatment process we observed decreases in DOC concentration (8.7-0.5 mg C L(-1)), SUVA (3.1-1.7 mg(-1) L m(-1)), and the average nominal molecular mass (670-440 Da). Meanwhile, water hardness was practically unaffected (iron concentrations were low (samples. Given the recommended limit of 4 mg L(-1) for chemical oxygen demand (COD) for Swedish drinking water, coagulation will need to be supplemented with one or more treatment steps irrespective whether climate change will lead to drier or wetter conditions in order to maintain sufficient DOC removal with the current increasing concentrations in raw waters.

  17. Nutrient and suspended solids removal from petrochemical wastewater via microalgal biofilm cultivation.

    Science.gov (United States)

    Hodges, Alan; Fica, Zachary; Wanlass, Jordan; VanDarlin, Jessica; Sims, Ronald

    2017-05-01

    Wastewater derived from petroleum refining currently accounts for 33.6 million barrels per day globally. Few wastewater treatment strategies exist to produce value-added products from petroleum refining wastewater. In this study, mixed culture microalgal biofilm-based treatment of petroleum refining wastewater using rotating algae biofilm reactors (RABRs) was compared with suspended-growth open pond lagoon reactors for removal of nutrients and suspended solids. Triplicate reactors were operated for 12 weeks and were continuously fed with petroleum refining wastewater. Effluent wastewater was monitored for nitrogen, phosphorus, total suspended solids (TSS), and chemical oxygen demand (COD). RABR treatment demonstrated a statistically significant increase in removal of nutrients and suspended solids, and increase in biomass productivity, compared to the open pond lagoon treatment. These trends translate to a greater potential for the production of biomass-based fuels, feed, and fertilizer as value-added products. This study is the first demonstration of the cultivation of mixed culture biofilm microalgae on petroleum refining wastewater for the dual purposes of treatment and biomass production. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. L’écodéveloppement participatif en question

    Directory of Open Access Journals (Sweden)

    Lucie Dejouhanet

    2010-03-01

    Full Text Available Si les politiques forestières indiennes ont évolué d’un paradigme directif à un paradigme participatif, les aires protégées sont encore gérées par des textes de loi qui privilégient la séparation entre activités humaines et espaces à protéger. L’écodéveloppement, soutenu par la Banque Mondiale, se voulait un moyen de favoriser des activités alternatives à l’exploitation des ressources et de faire participer les populations à la protection de leur environnement. Lancé en 2001 dans la réserve naturelle de Parambikulam au Kérala, ses résultats quelques années après sont peu concluants. Alors qu’un rapport de 2003 accuse le délitement social des populations concernées, cet article insiste davantage sur l’inadaptation des projets des comités d’écodéveloppement au contexte des villages ; le cliché essentialiste attaché aux populations adivasi constitue une vision a-historique qui ne permet pas de penser le développement aujourd’hui. L’écodéveloppement, s’il veut atteindre ses objectifs, doit permettre une réelle négociation entre acteurs des aires protégées et proposer des compromis réalistes entre limitation des activités et survie des populations.While Indian forest policies have evolved from a directive paradigm to a participative one, protected areas are still managed by legislative acts, which advocate a clear separation between human activities and areas to be protected. Eco-development financed by the World Bank was planned as a tool for developing alternative activities to resource exploitation and for involving local populations in environment protection through participation. Started in 2001 in the Wildlife Sanctuary of Parambikulam in Kerala, its results few years after are rather inconclusive. While a report in 2003 was accusing the social disintegration of concerned people, I am more stressing on the inappropriateness of EDC to villages’ context. The essentialist clich

  19. Uji Penurunan Kandungan COD, BOD pada Limbah Cair Pewarnaan Batik Menggunakan Scirpus Grossus dan Iris Pseudacorus dengan Sistem Pemaparan Intermittent

    Directory of Open Access Journals (Sweden)

    Bieby Voijant Tangahu

    2016-06-01

    Full Text Available Mostly, batik industrial wastewater is produced from batik coloring process. One of this batik industry is located in Jetis, Sidoarjo since 1675. The wastewater produced from the coloring process in this location is directly dumped to Jetis river or drainage system around the area. One of the effective, efficient, and not costly wastewater treatment is by using phytotreatment process.Plants used in this research are Scirpus grossus and Iris pseudacorus. Both of this plants can grow in polluted environment and suitable to be used in wastewater treatment process. Moreover, both of these plants are semi aquatic plant that can grow in both wet and dry condition. Intermittent exposure system can be applied to increase the efficiency of the phytotreatment process for batik industry wastewater. This system connects plant and wastewater periodically through flood and drain cycle (F/D. This exposure can increase redox condition, so it can increase removal efficiency.The study variables used in this research are species variation of plants Scirpus grossus and Iris pseudacorus (single plant or combined plant and intermittent exposure system variation, which is F/D 2:1 and F/D 1:2. The Primary parameter of this research is the concentration reduction of BOD, COD, and color. The secondary parameter such as plant morphology, wet weight, and dry weight, pH, and temperature.Preliminary research that has been done for this research is plant acclimatization and range finding test to determine the wastewater concentration. Phytotreatment test is conducted for 18 days in intermittent phase. The result shows that the best variable to remove pollutant is combined plant reactor with intermittent exposure of F/D 2:1 is able to remove 89% of COD and 97% of BOD.

  20. Screening of microalgae for integral biogas slurry nutrient removal and biogas upgrading by different microalgae cultivation technology.

    Science.gov (United States)

    Wang, Xue; Bao, Keting; Cao, Weixing; Zhao, Yongjun; Hu, Chang Wei

    2017-07-14

    The microalgae-based technology has been developed to reduce biogas slurry nutrients and upgrade biogas simultaneously. In this work, five microalgal strains named Chlorella vulgaris, Scenedesmus obliquus, Selenastrum capricornutum, Nitzschia palea, and Anabaena spiroides under mono- and co-cultivation were used for biogas upgrading. Optimum biogas slurry nutrient reduction could be achieved by co-cultivating microalgae (Chlorella vulgaris, Scenedesmus obliquus, and Nitzschia palea) with fungi using the pelletization technology. In addition, the effects of different ratio of mixed LED light wavelengths applying mixed light-emitting diode during algae strains and fungi co-cultivation on CO2 and biogas slurry nutrient removal efficiency were also investigated. The results showed that the COD (chemical oxygen demand), TN (total nitrogen), and TP (total phosphorus) removal efficiency were 85.82 ± 5.37%, 83.31 ± 4.72%, and 84.26 ± 5.58%, respectively at red: blue = 5:5 under the co-cultivation of S. obliquus and fungi. In terms of biogas upgrading, CH4 contents were higher than 90% (v/v) for all strains, except the co-cultivation with S. obliquus and fungi at red: blue = 3:7. The results indicated that co-cultivation of microalgae with fungi under mixed light wavelengths treatments was most successful in nutrient removal from wastewater and biogas upgrading.

  1. High-rate nitrogen removal and its behavior of granular sequence batch reactor under step-feed operational strategy.

    Science.gov (United States)

    Zhong, Chen; Wang, Yaqin; Wang, Yongjian; Lv, Junping; Li, Yaochen; Zhu, Jianrong

    2013-04-01

    Alternating anoxic/oxic (A/O) combined with the step-feed granular sequence batch reactor (step-feed SBR) was operated in laboratory scale to investigate nitrogen removal. The results showed that when the total inorganic nitrogen (TIN) and chemical oxygen demand (COD) levels were 55 and 320 mg/L in the influent, the TIN removal efficiencies were 89.7-92.4% in the step-feed mode and 48.1-59.5% in the conventional alternating A/O single-feed mode within a 360 min cycle. The pH and dissolved oxygen (DO) were used to optimize the process of denitrification and nitrification in the step-feed mode. The optimized operational condition was achieved by shortening the cycle time to 207 min, resulting in a nitrogen removal rate of 0.27 kg N/m3 d, which was much higher than those achieved using activated sludge systems. The dominant community in the aerobic granules was coccus-like bacteria, and filamentous bacteria were hardly found. Granules were well maintained throughout the 90 days of continuous step-feed operation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Effect of algae growth on aerobic granulation and nutrients removal from synthetic wastewater by using sequencing batch reactors.

    Science.gov (United States)

    Huang, Wenli; Li, Bing; Zhang, Chao; Zhang, Zhenya; Lei, Zhongfang; Lu, Baowang; Zhou, Beibei

    2015-03-01

    The effect of algae growth on aerobic granulation and nutrients removal was studied in two identical sequencing batch reactors (SBRs). Sunlight exposure promoted the growth of algae in the SBR (Rs), forming an algal-bacterial symbiosis in aerobic granules. Compared to the control SBR (Rc), Rs had a slower granulation process with granules of loose structure and smaller particle size. Moreover, the specific oxygen uptake rate was significantly decreased for the granules from Rs with secretion of 25.7% and 22.5% less proteins and polysaccharides respectively in the extracellular polymeric substances. Although little impact was observed on chemical oxygen demand (COD) removal, algal-bacterial symbiosis deteriorated N and P removals, about 40.7-45.4% of total N and 44% of total P in Rs in contrast to 52.9-58.3% of TN and 90% of TP in Rc, respectively. In addition, the growth of algae altered the microbial community in Rs, especially unfavorable for Nitrospiraceae and Nitrosomonadaceae.

  3. Modeling the removal of Sunfix Red S3B from aqueous solution by electrocoagulation process using artificial neural network

    Directory of Open Access Journals (Sweden)

    Manh Ha Bui

    2016-01-01

    Full Text Available This study presents an application of artificial neural networks (ANNs to predict the dye removal efficiency (color and chemical oxygen demand value of Electrocoagulation process from Sunfix Red S3B aqueous solution. The Bayesian regulation algorithm was applied to train the networks with experimental data including five factors: pH, current density, sulphate concentration, initial dye concentration (IDC, and electrolysis time. The predicting performance of the ANN models was validated through the low root mean square error value (9.844 %, mean absolute percentage error (13.776 % and the high determination coefficient value (0.836. Garson, Connection weight method and neural interpretation diagram were also used to study the influence of input variables on dye removal efficiency. For decolorization, the most effective inputs are determined as current density, electrolysis time and initial pH, while COD removal is found to be strongly affected by initial dye concentration and sulphate concentration. Through these steps, we demonstrated ANN’s robustness in modeling and analysis of electrocoagulation process.

  4. Microalgae consortia cultivation in dairy wastewater to improve the potential of nutrient removal and biodiesel feedstock production.

    Science.gov (United States)

    Qin, Lei; Wang, Zhongming; Sun, Yongming; Shu, Qing; Feng, Pingzhong; Zhu, Liandong; Xu, Jin; Yuan, Zhenhong

    2016-05-01

    The potential of microalgae consortia used in dairy wastewater treatment combined with microalgae biodiesel feedstock production was evaluated by comparing the nutrient removal of dairy wastewater, the growth of cells, and the lipid content and composition of biomass between monoalgae and microalgae consortia cultivation system. Our results showed that higher chemical oxygen demand (COD) removal (maximum, 57.01-62.86 %) and total phosphorus (TP) removal (maximum, 91.16-95.96 %) were achieved in almost microalgae consortia cultivation system than those in Chlorella sp. monoalgae cultivation system (maximum, 44.76 and 86.74 %, respectively). In addition, microalgae consortia cultivation except the mixture of Chlorella sp. and Scenedesmus spp. reached higher biomass concentration (5.11-5.41 g L(-1)), biomass productivity (730.4-773.2 mg L(-1) day(-1)), and lipid productivity (143.7-150.6 mg L(-1) day(-1)) than those of monoalgae cultivation (4.72 g L(-1), 674.3, and 142.2 mg L(-1) day(-1), respectively) on the seventh day. Furthermore, the fatty acid methyl ester (FAME) profiles indicated the lipids produced from microalgae consortia cultivation system were more suitable for biodiesel production. The microalgae consortia display superiority in dairy wastewater treatment and the getting feedstock for biodiesel production.

  5. Estimating abundances of 0-group western Baltic cod by using pound net fisheries

    DEFF Research Database (Denmark)

    Bauer, Robert; Stepputtis, Daniel; Storr-Paulsen, Marie

    2010-01-01

    Nearshore 0-group western Baltic cod are frequently caught as bycatch in the commercial pound net fishery. Pound net fishermen from the Danish Isle of Funen and Lolland and the German Isle of Fehmarn have recorded their catches of small cod between September and December 2008. Abundance patterns...

  6. The invasive ctenophore Mnemiopsis leidyi poses no direct threat to Baltic cod eggs and larvae

    DEFF Research Database (Denmark)

    Jaspers, Cornelia; Titelman, Josefin; Hansson, Lars Johan

    2011-01-01

    Since its invasion in to the Baltic Sea in 2006, the ctenophore Mnemiopsis leidyi has been suspected of seriouspredation on the early life stages of Baltic cod (Gadus morhua callarias L.) due to a temporal and spatial overlap inthe most important cod spawning ground, the Bornholm Basin. We conduc...

  7. Hazard Analysis and identification of Critical Control Points of collagen extraction from cod by-products

    NARCIS (Netherlands)

    Aalberts, C.H.J.

    2004-01-01

    The aim of the European research project “UTILISATION AND STABILISATION OF BY-PRODUCTS FROM COD SPECIES” (QLK1-CT-2000-01017 QLRT-2001-02829) is to investigate whether collagen from fish by-products could serve as an important raw material in high quality food. Since Atlantic cod is a major commodit

  8. Prediction of selectivity from morphological conditions: Methodology and a case study on cod (Gadus morhua)

    DEFF Research Database (Denmark)

    Herrmann, Bent; Krag, Ludvig Ahm; Frandsen, Rikke

    2009-01-01

    The FISHSELECT methodology. tools, and software were developed and used to measure the morphological parameters that determine the ability of cod to penetrate different mesh types, sizes, and openings. The shape of one cross-section at the cod's head was found to explain 97.6% of the mesh...

  9. Proteome reference map of the skin mucus of Atlantic cod (Gadus morhua) revealing immune competent molecules

    NARCIS (Netherlands)

    Rajan, B.; Fernandes, J.M.O.; Caipang, C.M.A.; Kiron, V.; Rombout, J.H.W.M.; Brinchmann, M.

    2011-01-01

    The skin mucosal proteome of Atlantic cod (Gadus morhua) was mapped using a 2D PAGE, LC–MS/MS coupled approach. Mucosal proteins from naive fish were identified primarily by similarity searches across various cod EST databases. The identified proteins were clustered into 8 groups based on gene ontol

  10. Preparation, characterization, and in vitro cytotoxicity of COM and COD crystals with various sizes.

    Science.gov (United States)

    Sun, Xin-Yuan; Ouyang, Jian-Ming; Liu, Ai-Jie; Ding, Yi-Ming; Gan, Qiong-Zhi

    2015-12-01

    Calcium oxalate crystals in urine often differ in size and crystal phase between healthy humans and patients with kidney stones. In this work, calcium oxalate monohydrate (COM) and dihydrate (COD) with sizes of about 50 nm, 100 nm, 1 μm, 3 μm, and 10 μm were prepared by varying reactant concentration, reaction temperature, solvent, mixing manner, and stirring speed. These crystals mainly had a smooth surface and no obvious pore structure, except COM-1 μm. In cell culture medium, the zeta potential of crystals became increasingly negative with increasing size, and the absolute value of zeta potential of COD was greater than the same-sized COM. Results of cell viability and PI staining assays showed that the order of injury degree in African green monkey renal epithelial (Vero) cells caused by different sizes of COD was COD-50 nm>COD-100 nm>COD-1 μm>COD-3 μm>COD-10 μm, and that of different sizes of COM was COM-1 μm>COM-50~COM-100 nm>COM-3 μm>COM-10 μm. COM-1 μm presented the highest cytotoxicity in Vero cells, which was associated with its rougher surface, larger specific surface area (SBET), and larger pore volume. Overall, these findings indicated that the physical properties of crystals play an important role in their cytotoxicity.

  11. Evaluation of Electrical Stunning of Atlantic Cod (Gadus morhua) and Turbot (Psetta maxima) in Seawater

    NARCIS (Netherlands)

    Lambooij, E.; Digre, H.; Erikson, U.; Reimert, H.G.M.; Burggraaf, D.; Vis, van de J.W.

    2013-01-01

    The aim of this study was to assess electrical stunning of Atlantic cod and turbot in seawater to develop a protocol for the process of stunning and killing. An induced general epileptiform insult (unconscious) had a duration of 40 ± 27 s (n =14) in cod (2.6 ± 0.5 kg) and 34 ± 18 s (n = 19) in turbo

  12. Removal of toxic metals during biological treatment of landfill leachates.

    Science.gov (United States)

    Robinson, T

    2017-05-01

    Progressive implementation of the European Water Framework Directive has resulted in substantial changes in limits for discharges of heavy metals both to watercourses, and to sewer. The objective of this paper is to provide original, real, full-scale data obtained for removal of metals during aerobic biological leachate treatment, and also to report on studies carried out to look at further trace metal removal. Polishing technologies examined and investigated include; the incorporation of ultrafiltration (UF) membranes into biological treatment systems, the use of ion exchange, and of activated carbon polishing processes. Ultrafiltration was able to provide a 60 percent reduction in COD values in treated leachates, compared with COD values found in settled/clarified effluents. Removal rates for COD varied from 30.5 to 79.8 percent. Additionally, ultrafiltration of treated leachates significantly reduced both chromium and nickel concentrations of effluents by 61.6% and 34.3% respectively (median values). Despite mean reductions of chromium (9.7%) and nickel (13.7%) noted during the ion exchange trials, these results would not justify use of this technology for metals removal at full-scale. Further preliminary studies used pulverized activated carbon (PAC) polishing of UF effluents to demonstrate that significant (up to 80 per cent) removal of COD, TOC and heavy metals could readily be achieved by doses of up to 10g/l of suitable activated carbons. Additional evidence is provided that many trace metals are present not in ionic form, but as organic complexes; this is likely to make their removal to low levels more difficult and expensive. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. A genomic island linked to ecotype divergence in Atlantic cod

    DEFF Research Database (Denmark)

    Hansen, Jakob Hemmer; Eg Nielsen, Einar; Therkildsen, Nina O.;

    2013-01-01

    gene flow and large effective population sizes, properties which theoretically could restrict divergence in local genomic regions. We identify a genomic region of strong population differentiation, extending over approximately 20 cM, between pairs of migratory and stationary ecotypes examined at two......The genomic architecture underlying ecological divergence and ecological speciation with gene flow is still largely unknown for most organisms. One central question is whether divergence is genome‐wide or localized in ‘genomic mosaics’ during early stages when gene flow is still pronounced....... Empirical work has so far been limited, and the relative impacts of gene flow and natural selection on genomic patterns have not been fully explored. Here, we use ecotypes