Cho, Kangwoo Chung, Chong Min Kim, Yun Jung Hoffmann, Michael R. Chung, Tai Hak 2024-01-20T11:30:28Z 2024-01-20T11:30:28Z 2021-09-05 2013-10-01 0959-3330 https://pubs.kist.re.kr/handle/201004/127552 Stringent water treatment criteria and rapidly growing pollutant loads provoke the demand for retrofitting wastewater treatment plants towards a higher capacity. In this study, we assess a two stage alternating aeration (AA) bioreactor equipped with electroflotation (EF) clarifier, for nitrogen removal within a short hydraulic reTENTion time (HRT). The EF under steady solids loading required a minimum unit height and gas:solids ratio of 0.006 for efficient clarification. The separated sludge blanket was further thickened with retaining stability when the cyclic solids loading was smaller than 1.0kgm(-2). In the continuous operation of the bioreactor, the returned activated sludge concentration increased to more than 18,000mgL(-1), while the effluent suspended solids concentration was lowered below 5mgL(-1). Under influent chemical oxygen demand (COD)/total inorganic nitrogen (TIN) concentration of 300/30mgL(-1), the TIN removal efficiency was near 70% with cycle time ratios of 0.17 and 0.27. Under higher influent COD concentration of 500mgL(-1), TIN removal efficiency was found to be 73.4% at a carbon:nitrogen (C:N) ratio of 10 and even higher (80.4%) at a C:N ratio of 16.6. The increased mixed liquor suspended solids concentrations (>6000mgL(-1)) under the high COD loading were efficiently maintained by using the EF clarifier. The results of this study demonstrate that an EF clarifier with a HRT of less than 1 h can support reliable nitrogen removal in the AA process that has a HRT of 6h, even under increasing influent loadings. English TAYLOR & FRANCIS LTD DISSOLVED AIR FLOTATION ACTIVATED-SLUDGE PROCESS WASTE-WATER TREATMENT INTERMITTENT-AERATION ELECTROLYTIC BUBBLES MEMBRANE BIOREACTOR PHOSPHORUS REMOVAL DESIGN FLOW CLARIFICATION Electroflotation clarifier to enhance nitrogen removal in a two-stage alternating aeration bioreactor Article 10.1080/09593330.2013.788072 1 ENVIRONMENTAL TECHNOLOGY, v.34, no.19, pp.2769 - 2776 ENVIRONMENTAL TECHNOLOGY 34 19 2769 2776 scie scopus 000329338100011 2-s2.0-84897019850 Environmental Sciences Environmental Sciences & Ecology Article DISSOLVED AIR FLOTATION ACTIVATED-SLUDGE PROCESS WASTE-WATER TREATMENT INTERMITTENT-AERATION ELECTROLYTIC BUBBLES MEMBRANE BIOREACTOR PHOSPHORUS REMOVAL DESIGN FLOW CLARIFICATION wastewater treatment alternating aeration bioreactor electroflotation activated sludge nitrogen removal