TWO PHASE UPFLOW ANAEROBIC SLUDGE BLANKET (UASB) REACTOR ON THE REDUCTION OF CHEMICAL OXYGEN DEMAND IN DAIRY EFFLUENT

An increasing pollution level leads to realization of the potential of anaerobic treatment. This led to the development of a range of reactor designs suitable for the treatment of low, medium and high strength waste water. With the increasing use of anaerobic technology for treating various process streams, it is expected that industries would become more economically competitive because of their more judicious use of natural resources. One of the most developments in anaerobic treatment process technology was the Upflow Anaerobic Sludge Blanket reactors. The reactor is being used extensively for a large number of different types of industrial effluents. Prevention and reduction of dairy waste water pollution can be achieved by means of direct recycling and reutilization of waste components. This study examined the feasibility of applying Upflow Anaerobic Sludge Blanket bioreactor with phase separation i.e. acidogenesis and methanogenensis, to treat dairy effluent. The aim of the study is developing anaerobic digestion as a two-phase process originated from the view that it is generally a process involving two different set of activities. The two reactors were constructed in transparent acrylic sheet. The dimension of the acidogenic reactor was 18 cm width, 18 cm breadth and 50 cm height. In the present study, the better performance of the reactors than the reactors reported by other investigators can be attributed to two reasons. One definite reason is the phase separation. In the present study, the high chemical oxygen demand removal rate achieved at a hydraulic retention time 2 days for the acidogenic reactor at an OLR rate of 4.01-4.21 kg chemical oxygen demand /m3/day and in the methanogenic reactor hydraulic retention time of 2.5 days at an organic loading rate 2.61-2.75 kg chemical oxygen demand. The results indicate that a sharp decrease in the chemical oxygen demand removal efficiency for loads above 2-4 g chemical oxygen demand /l/day in the operation of sludge bed anaerobic reactors fed with dairy effluents. Among the anaerobic treatment two phase Upflow Anaerobic Sludge Blanket reactor work efficiently to treat also to mitigate the issue of acidification nature of dairy effluent.