Parametric Studies of Biochemical Oxygen Demand through Improvised Respirometric Systems

Abstract

To overcome the limitation of the dilution technique for BOD, a respirometer and disposable respirometric BOD bottles were fabricated. In the improvised respirometric BOD systems, the wastewater sample was surrounded by a polyethylene membrane permeable to oxygen. Contents of the respirometer were continuously stirred and D.O. was determined with a D.O. probe whereas the contents of respirometric BOD bottles were not stirred and D.O. was determined by Winkler's Method. Mass transfer co-efficients were estimated for the two respirometric BOD systems. BOD exertion of 50 to 200 mg/1 of standard glucose, glutamic acid synthetic waste was studied in the two respirometric BOD systems. The BOD exertion curve was divided into bacterial growth phase and endogenous phase. Logistic curve was fitted to bacterial growth phase. BOD exerted, till the stoichiometric end point of the BOD reaction was termed as limiting growth BOD (L). Co-efficient of correlation between L and TOD was 0.98. Relationship between 2 day respirometric BOD and 5-day standard BOD gave a co-efficient of correlation of 0.99. The respirometric systems, developed in the present investigations, show a lot of promise in conventional research and modeling of BOD.