Studies on biodegradation of organic waste in uasb reactor

Abstract

The industrialization in the developing countries causes severe problems in collection,treatment and disposal of organic effluents. The situation leads to public health andenvironmental problem. Therefore, various high rate anaerobic treatments has beenemerged as a variable alternative for the treatment of many industrial and domesticwastewater containing organic wastes. In this study high rate Upflow Anaerobic SludgeBlanket (UASB) reactor has been critically analyzed, discussed and designed as thesolution of above problem. According to that a UASB reactor has been fabricated forlaboratory study. The UASB system appeared to be economically cost effective ascompared to other systems. This paper also focuses on the principle of startup,operational performance, chemical oxygen demand (COD) removal efficiency, methaneproduction rate, and specific methanogenic activity in the UASB reactor. In the presentstudy, reactor was started initially with mixture of molasses and glucose (50% each)solution with organic loading rate (OLR) 0.933 g COD/L day. Thereafter, OLR is beingincreased in steps. After 15 days of startup of reactor, molasses solution was applied. Thetemperature (35e° C), pH (6.8±0.4), and nutrients requirement were maintained. In thisstudy COD: N: P ratio were maintained at 300: IO: l by adding urea for nitrogen andpotassium di-hydrogen phosphate for phosphorus. For a change of OLR up to 13.33gCOD/L day, all above-mentioned parameter were studied. The removal efficiency andgas production rate depend on activity of granules. A typical organic degrading granule iscomposed of micro-colonies of Methanothrix and several syntropic micro -colonies.