TRACING POLLUTIONAL PARAMETERS THROUGH A UASB PLANT

Abstract

Recently, upflow anaerobic sludge blanket (UASB) type sewage treatment plants (STP) have been constructed at several places in India for the treatment of municipal wastewaters. Although these plants are working as expected but there are many aspects about which adequate information is not available. Throughout the world extensive research work on UASB process is going on at several places. In the present dissertation, efforts were made to address the following aspects. (i) To trace different pollutional parameters through a UASB type STP and find out the range of removal which could be achieved at different stages of treatment i.e. preliminary by screen and grit chamber, secondary by UASB, and tertiary by polishing ponds, (ii) to study th, profile of substrate and sludge in bed and blanket and (iii) to carry out COD and BODU ma balance in UASB reactor. For the study, 38ML/d UASB-STP located at Saharanpur was selected. Wastewat samples were collected from different stages of the treatment from December 2002 to Jan 2003. Samples were analyzed for different parameters namely- COD (total & filtera BOD327°c (total & filterable), pH, Temperature, TS, TDS, TSS, TVS, VDS, VSS, ORP, sul1 D.O., nitrates, and phosphates. To assess the treatment profile, sludge samples from difi sampling ports of UASB were also collected in the month of February, 2003 for a period days. All samples were analyzed for COD (total & filterable), TS, TSS, TVS and VSS. The overall percent removals were found to vary from 80-90% for BOD, COD, TS VSS. Maximum removal occurred in UASB reactors. The effluent BOD3 27° C 31-36 mg/1 found to be marginally more than the Indian effluent discharge standards of 30 mg/L. D.O. treated effluent was found to be in the rage of 4.0-5.5 mg/L. Distinct profiles of the solubl, particulate COD were observed in the bed and the blanket of reactor. USAB reactor also beh as hydrolytic chamber in addition to acidogenic and methogenic chamber. As strategy for COD and BODU mass balance was evolved. On an average, Saharanpur plant, COD mass balance revealed that effluent contained 38-40% of incoming CO 18-22% was used for production of gas, 24-28% was for converted into gas dissolved in efflu( and 6-8% was used for sludge productions. Incoming COD, which could not be accounted ranged for 10-15%.