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COD Removal Efficiency (cod + removal_efficiency)
Selected AbstractsTreatment of Highly Contaminated Groundwater: A SITE Demonstration ProjectREMEDIATION, Issue 3 2001Daniel Sullivan From September through November 1994, the U.S. Environmental Protection Agency (EPA) conducted a field demonstration of the remediation of highly contaminated groundwater at the Nascolite Superfund site located in Millville, New Jersey. Besides high concentrations of the major contaminant, methyl methacrylate (MMA), the groundwater also contained small amounts of volatile and semivolatile organic compounds. ZenoGem® technology, an integrated bioreactor and ultrafiltration membrane system, was employed for this demonstration project. Approximately 30,000 gallons of groundwater containing MMA in concentrations of 567 to 9,500 milligrams per liter (mg/L) and chemical oxygen demand (COD) values ranging from 1,490 to 19,600 mg/L was treated. The demonstration focused on the system's ability to remove MMA and reduce COD from the groundwater. Results of the three-month demonstration showed that average MMA and COD removal efficiencies were greater than 99.9 and 86.9, respectively. The total cost of treatment, depending on the duration of the project, is estimated to vary from $0.22 to $0.55 (in 1994 dollars) per gallon of groundwater treated. © 2001 John Wiley & Sons. [source] Biological treatment of milk processing wastewater in a sequencing batch flexible fibre biofilm reactorASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Mohamed Abdulgader Abstract Biological treatment of dairy wastewater was investigated using a laboratory scale aerobic sequencing batch flexible fibre biofilm reactor (SBFFBR). The SBFFBR system was modified from a typical sequencing batch reactor system by using eight flexible fibre bundles with a very high specific surface area, which served as support for microorganisms. The reactor was operated under different influent chemical oxygen demand (COD) concentrations (610, 2041 and 4382 mg l,1) and constant hydraulic retention times of 1.6 days. The results have shown successful applicability of the SBFFBR system to treat this dairy wastewater. High COD removal efficiencies between 89.7 and 97% were achieved at average organic loading rates of 0.4 and 2.74 kg COD m,3 d,1, respectively. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Post-treatment of anaerobically treated medium-age landfill leachateENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2010Ebru Akkaya Abstract This study focused on the removal of COD and NH4+ from medium-age leachate. Experiments were performed in a laboratory-scale upflow anaerobic sludge blanket (UASB), a membrane bioreactor (MBR), and using magnesium ammonium phosphate (MAP) precipitation. MBR and MAP were used for the post-treatment steps for anaerobically treated leachate to increase the removal of organics and ammonium. The UASB reactor removed nearly all biodegradable organics and supplied constant effluent COD for all concentration ranges of influent leachate. Ammonium removal efficiency in the UASB reactor was relatively low and the average value was ,7.9%. Integration of MBR to the effluent of UASB reactor increased the average COD removal efficiency from 51.8 to 65.6% and maximum removal efficiency increased to 74.3%. MAP precipitation was applied as a final step to decrease the ammonium concentration in the effluent of UASB+MBR reactors. The effect of pH and the molar ratio of MAP constituents on the removal of ammonium were evaluated. At optimal conditions (pH: 9.0 and Mg/NH4/PO4: 1/1.2/1.2), 96.6% of ammonium was removed and MAP provided additional COD and turbidity treatment. Consequently, the combined system of MBR and MAP precipitation could be used as an appropriate post treatment option for the anaerobically treated medium-age landfill leachate. © 2009 American Institute of Chemical Engineers Environ Prog, 2010 [source] Effect of a chemical synthesis-based pharmaceutical wastewater on performance, acetoclastic methanogenic activity and microbial population in an upflow anaerobic filterJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2002B Kasapgil Ince Abstract The performance of an upflow anaerobic filter (UAF) treating a chemical synthesis-based pharmaceutical wastewater was evaluated under various operating conditions. During start-up, the UAF was initially fed by glucose till an organic loading rate (OLR) of approximately 7.5,kg COD m,3 day,1 with a hydraulic retention time of 2.3 days. A soluble COD removal efficiency of 98% was achieved before the addition of the wastewater. Initially, the filter inertia was acclimatized to the wastewater by sequential feeding of 10% (w/v), 30% (w/v) and 70% (w/v) of the pre-aerated wastewater mixed with glucose followed by a 100% (w/v) pre-aerated wastewater. During the operation, the COD removal efficiency and methane yield decreased to 75% and 0.30,m3 CH4,kg,1 CODremoved respectively. As the UAF became accustomed to the pre-aerated wastewater, raw wastewater was fed in increasing ratios of 20% (w/v), 60% (w/v) and 80% (w/v) with the pre-aerated wastewater as the remaining part. During this stage of the operation, a COD removal efficiency in a range of 77,86% was achieved and the methane yield decreased to 0.24,m3 CH4,kg,1 CODremoved. Finally, 100% (w/v) raw wastewater was fed and a COD removal efficiency of 65% was achieved with a methane yield of 0.20,m3 CH4,kg,1 CODremoved. At the end of the operation, acetoclastic methanogenic activity was only measured in the bottom section of the UAF, this showed a 90% reduction in comparison with activity of inoculation sludge. Microscopic examinations revealed that rod-shaped methanogens remained as the dominant species whereas Methanosarcina -like species and filaments were present only in insignificant numbers along the UAF. © 2002 Society of Chemical Industry [source] Effect of seeding sludge type and hydrodynamic shear force on the aerobic sludge granulation in sequencing batch airlift reactorsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009K. Y. Koh Abstract Two sequencing batch airlift reactors (SBARs) were operated simultaneously for two separate runs. In the first run, two different types of seeding sludge were cultivated in two separate reactors under the same superficial air velocity (SAV). In the second run, the same seeding sludge was cultivated in both reactors but under different SAV, i.e. 1.2 and 3.6 cm s,1. Both runs were carried out for a period of about 20 days, during which the chemical oxygen demand (COD) removal efficiency and morphology of sludge were examined. Batch tests using sodium acetate as the main carbon source were conducted to investigate the COD removal efficiency, and the morphologies of sludge were examined under light microscopy. Results showed that the COD removal efficiency improved with cultivation time. Morphological study showed that all cultivated sludge lost their filamentous species after a few days of cultivation, leaving behind communities of loosely packed pellet-like groups. Although the SAV recommended by other researchers was applied to the SBAR, granulation did not take place at the end of both experimental runs. It was suspected that the failure for aerobic sludge to granulate under the selected operating strategies and reactor configuration was partly due to the intrinsic traits of the sludge microbial community. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Novel application of oxygen-transferring membranes to improve anaerobic wastewater treatmentBIOTECHNOLOGY & BIOENGINEERING, Issue 4 2005Anthony S. Kappell Abstract Anaerobic biological wastewater treatment has numerous advantages over conventional aerobic processes; anaerobic biotechnologies, however, still have a reputation for low-quality effluents and operational instabilities. In this study, anaerobic bioreactors were augmented with an oxygen-transferring membrane to improve treatment performance. Two anaerobic bioreactors were fed a synthetic high-strength wastewater (chemical oxygen demand, or COD, of 11,000 mg l,1) and concurrently operated until biomass concentrations and effluent quality stabilized. Membrane aeration was then initiated in one of these bioreactors, leading to substantially improved COD removal efficiency (>95%) compared to the unaerated control bioreactor (,65%). The membrane-augmented anaerobic bioreactor required substantially less base addition to maintain circumneutral pH and exhibited 75% lower volatile fatty acid concentrations compared to the unaerated control bioreactor. The membrane-aerated bioreactor, however, failed to improve nitrogenous removal efficiency and produced 80% less biogas than the control bioreactor. A third membrane-augmented anaerobic bioreactor was operated to investigate the impact of start-up procedure on nitrogenous pollutant removal. In this bioreactor, excellent COD (>90%) and nitrogenous (>95%) pollutant removal efficiencies were observed at an intermediate COD concentration (5,500 mg l,1). Once the organic content of the influent wastewater was increased to full strength (COD = 11,000 mg l,1), however, nitrogenous pollutant removal stopped. This research demonstrates that partial aeration of anaerobic bioreactors using oxygen-transferring membranes is a novel approach to improve treatment performance. Additional research, however, is needed to optimize membrane surface area versus the organic loading rate to achieve the desired effluent quality. © 2005 Wiley Periodicals, Inc. [source] | ||||||||||