A STUDY OF COD REDUCTION PROFILE IN UASB REACTOR

Abstract

Now a days energy considerations and environmental concerns have increased the interest in direct anaerobic treat-ment of industrial. wastes. The anaerobic method of waste treat-ment offers a number of significant advantages with little serious or insuperable drawbacks. The concept of UASB reactor was first investigated by Hermes et al, (1962). This concept has been extensively developed by Lettinga and co-workers in the 70's (Lettinga at al. 1980)0 under the UASB.(Upflow Anaerobic Sludge Blanket) designation. It has been successfully applied at Pilot Scale and at full scale to a variety of wastewaters. Essen-tially, the UASB process consists of an upward flow of the waste stream through a dense bed of biomase sludge formed into granules of 1-5 min diameter*, then a less dense blanket of suspended flocs. Thereafter, the waste leaves the reactor via a gas solid separation device at the top of the reactor. In order to design/ scale up and optimize UASB reactor one must know the fluid flow phenomenon, behaviour of different compartments, kinetics of microorganisms and mass transport phenomenon between different compartments and phases. As a part of this, to ascertain behaviour and role of different compartments in waste strength reduction vertical treatment profile study has been taken. Three laboratory scale reactors operating at different organic and sludge loadings have been used. The synthetic waste used for the study was prepared by dissolving cane sugar molasses in tape water. The samples have been collected at different heights of the reactors, The treatment profiles have been obtgned by analysing six sets. of samples in duplicate from three reactors. The various parameters analysed for the study are pH, Chemical Oxygen Demand (COD) 0. Suspended Solids, Volatile Suspended Solids, Dissolve Organic Carbon, Oas Product ion with Percentage Methane content. In initial set total nitrogen was also '