On-site nutrient removal using a 5-stage biological reactor (original) (raw)
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Bioresource Technology, 2009
The performance of a pilot-scale biological nutrient removal process has been evaluated for 336 days, receiving the real municipal wastewater with a flowrate of 6.8 m 3 /d. The process incorporated an intermittent aeration reactor for enhancing the effluent quality, and a nitrification reactor packed with the porous polyurethane foam media for supporting the attached-growth of microorganism responsible for nitrification. The observation shows that the process enabled a relatively stable and high performance in both organics and nutrient removals. When the SRT was maintained at 12 days, COD, nitrogen, and phosphorus removals averaged as high as 89% at a loading rate of 0.42-3.95 kg COD/m 3 d (corresponding to average influent concentration of 304 mg COD/L), 76% at the loading rate of 0.03-0.27 kg N/m 3 d (with 37.1 mg TN/L on average), and 95% at the loading rate of 0.01-0.07 kg TP/m 3 d (with 5.4 mg TP/L on average), respectively.
MATEC Web of Conferences
Water utilities, commercial and industrial establishments are required to upgrade or install new treatment systems to comply with the revised effluent standards issued by the Department of Environment and Natural Resources – Environment Management Bureau (DENR – EMB) which now includes removal and monitoring of nutrients (nitrogen and phosphorus components). One solution is to utilize a biological nutrient removal technology (BNRT) system capable of removing nutrients from sewage. The on-going study aims to investigate the performance of the pilot-scale system in the removal of nutrients from sewage. The designed pilot-scale anaerobic-anoxic-oxic (A2O) process with a total hydraulic retention time of 8.37 hrs. was operated in an existing sewage treatment plant (STP). System modification was adapted to ensure continuous operation. Dissolved oxygen (DO) and temperature of each compartment were evaluated after 45 days of system modification. The DO of the anaerobic and oxic compartment...
Bioresource Technology, 2010
The performance of an MBR pilot plant for biological nutrient removal was evaluated during 210 days of operation. The set point values for the internal recycles were determined in advance with the use of an optimisation spreadsheet based on the ASM2d model to optimise the simultaneous removal of C, N and P. The biological nutrient removal (BNR) efficiencies were high from the start of operation with COD and N removal efficiencies of 92 ± 6% and 89 ± 7, respectively. During the course of the experiment P removal efficiencies increased and finally a P-removal efficiency of 92% was achieved. The activity of poly-phosphate accumulating organisms (PAOs) and denitrifying poly-phosphate accumulating organisms (DPAOs) increased and the specific phosphate accumulation rates after 150 days of operation amounted to 13.6 mg P g À1 VSS h À1 and 5.6 mg P g À1 VSS h À1 , for PAOs and DPAOs, respectively.
Biological Nutrient Removal in Municipal Wastewater Treatment: New Directions in Sustainability
Journal of Environmental Engineering, 2012
To control eutrophication in receiving water bodies, biological nutrient removal (BNR) of nitrogen and phosphorus has been widely used in wastewater treatment practice, both for the upgrade of existing wastewater treatment facilities and the design of new facilities. However, implementation of BNR activated sludge AS systems presents challenges attributable to the technical complexity of balancing influent chemical oxygen demand (COD) for both biological phosphorus (P) and nitrogen (N) removal. Sludge age and aerated/unaerated mass fractions are identified as key parameters for process optimization. Other key features of selected BNR process configurations are discussed. Emerging concerns about process sustainability and the reduction of carbon footprint are introducing additional challenges in that influent COD, N, and P are increasingly being seen as resources that should be recovered, not simply removed. Energy recovery through sludge digestion is one way of recovering energy from influent wastewater but which presents a specific challenge for BNR: generation of sidestreams with high nutrient and low COD loads. Technologies designed specifically to treat these side-stream loads are overviewed in this paper. Finally, relatively high levels of nitrous oxide emissions, a powerful greenhouse gas, have been shown to occur in the BNR process under certain conditions, particularly in the presence of high nitrite concentrations. The advantages of using process modeling tools is discussed in view of optimizing BNR processes to meet effluent requirements and to meet goals of sustainability and reducing carbon footprints.
Biological Nutrient Removal: Design Snags, Operational Problems and Costs
Water and Environment Journal, 1995
The EC urban waste water treatment Directive will lead to some sewage-treatment works in the UK having to remove nitrogen and phosphorus. The paper reviews the basic biological processes which are available for retrofitting existing activated-sludge plants to achieve this removal, and then points to some of the problems which are encountered with these processes in other countries. The authors make suggestions as to how these problems can be overcome in design and operation. The paper also provides a cost comparison of different ways of uprating an existing nitrifying activated-sludge plant to achieve nitrification/ denitrification and phosphorus removal.
1999
ÐExperiments in a continuous UCT-bench scale plant using synthetic wastewater, have been carried out to demonstrate the feasibility of using the biodegradable organic fraction of municipal solid waste (BOF-MSW) as an easily biodegradable C source for nitrogen and phosphorous removal. Yields obtained are quite good and the additional load introduced by the use of the fermentation products of the BOF-MSW can be considered negligible. In addition, the basic mass balances carried out, show that the amount of easily biodegradable C-source needed to treat the wastewater produced by a given unit of persons can be obtained from the amount of BOF-MSW generated by this unit.
Comparative Assessment of a Novel MBR and A2O for Biological Nutrient Removal
Proceedings of the Water Environment Federation, 2008
A comparative study between two biological nutrient removal (BNR) systems i.e. one employing membranes and the other conventional A2O system was conducted at the hydraulic retention time (HRT) and solids retention time (SRT) of 8 h and 10 d respectively using synthetic wastewater (SWW) and municipal wastewater (MWW) which contains 30% of the volatile fatty acid (VFA) of the SWW. Achieved COD, N and P removal efficiencies for the MBR were 95-98, 72-75 and 70-91%, respectively, compared to 95-98, 70-76 and 70-77% for the A2O. It was confirmed that the primary factor governing P removal is VFA concentration. Accordingly, the contribution of denitrifying phosphorus accumulating organisms (DPAOs) to P removal was greatly hampered. However, the impact of an intermediate clarifier P removal in the MBR was significant for both SWW and MWW runs.
Desalination, 2010
This study shows that an MBR pilot plant with UCT configuration is able to obtain high nutrient removal efficiency already during start-up. The biological nutrient removal (BNR) efficiencies significantly increased towards the end of the experimental run, achieving a COD removal efficiency exceeding 94% and N removal efficiency in the range of 89 to 93%. P removal efficiencies in the range of 80 to 92% have been obtained. During the experimental period (4 months) the evolution of the activity of polyphosphate-accumulating organisms, obtained from P release and P uptake rates, showed a small increase in the activity of polyphosphateaccumulating organisms (PAOs) and denitrifying polyphosphate-accumulating organisms (DPAOs). The specific phosphate accumulation at the end of the experimental run amounted to 8.0 mg P g − 1 VSS h − 1 and 3.29 mg P g − 1 VSS h − 1 , for the PAOs and DPAOs respectively. Moreover, the DPAOs activity increased faster than PAOs activity, i.e. from 0.36 to 0.41 of phosphate uptake rate (PUR) ratio.