Performance of UASB based sewage treatment plant in India: polishing by diffusers an alternative

摘要

In India, recently, upflow anaerobic sludge blanket (UASB) based sewage treatment plants (STPs)nhave come up in a big way. Sequence adopted: screens- grit chambers- UASB reactors followednby one-day detention ponds (DP). Performance of DPs located at five STPs (27–70 ML/d) wasnevaluated over a period of one year from July 2004 to July 2005. The installation of these non-algalnponds reduced land requirement, but from treatment point of view it at best offered only removalnof solids washed out of the UASB reactor. Total coliform count in the effluent from ponds rangingnfrom 106 to 109 MPN/100 mL is more than the maximum permissible limit of 10,000 MPN/100 mL.nA need has, therefore, been felt to evaluate the possibility of aerating the effluent from UASBR.nDuring aeration, ORP and DO increase, whereas COD and BOD decrease. In a continuous aerationn~50% reduction in COD and nearly 50% increase in DO saturation (DO/DOs) can be achieved bynincreasing ORP from u0002100 to 122 mV. Regression equation established between ORP and CODCODi & DO/DOs may find wide application.