Performance Evaluation of Oxidation Based Sewage Treatment Plant

Abstract

Oxidation ponds are recognized as the solution to domestic wastewater treatment in developing countries. The use of such natural systems is considered to be very important. This is because it is cheap, easy to construct and they do not require high skilled labor. In the developing countries the objectives for wastewater treatment should put emphasis on pathogen removal since most diseases and deaths in these areas are caused by poor sanitation. The efficiency in the removal of pathogens in oxidation ponds has been found to be very good. Oxidation ponds are mostly designed using empirical formulas derived either from past experience or from performance of already existing STPs elsewhere. Actual performance of the STP can differ from that of design mainly due to differences in sewage characteristics & local conditions. This study is an attempt in this direction. Samples were collected in month of February and March from two types of aeration pond systems one with laminar flow inversion technique and second with jet aerators. There were two ponds in series each type of aeration system. Sampling points were inlet to first pond(P1), two points along the length of first pond at one-third and two-third of length(P2,P3), inlet to second pond(P4), two points along the length of second pond at one-third and two-third of length(P5,P6) and outlet to second pond(P7) for both type of aeration system. In the pond samples were taken and analyzed at three different depths. Treated effluent of the STP was found complying with the prescribed standards.