Evaluation of the Efficiency of Surface Aerator in the Activated Sludge Process Treatment of Food Processing Effluent

Food processing units is a diversified activity consists of processing of perishable items such as fruit and vegetables, meat and poultry etc. into a various products without the loss of nutritional properties. Liquid waste is generated more in the Food processing units by means of washing of raw materials, pulping, crushing and canning operations. Hence, it is necessary to treat the effluent from the food processing units and to find the suitable ways of reusing the treated effluent water like gardening and other cleaning purpose etc., The effluent coming from food processing units contains large quantity of organic and inorganic materials which gives adverse effect to the environmental system when it is discharged directly without proper treatment system. The level of physical, chemical and biological characters have to be analyzed and the treatment system needs to be designed accordingly with proper analysis and environmental control. All effluent and wastewater containing biodegradable constituents which can be treated biologically in which the dissolved and particulate biodegradable constituents have been oxidized into acceptable forms. Hence, the reduction of Bio-chemical Oxygen Demand (*BOD) and Chemical Oxygen Demand (**COD) are the predominant factors in the biological treatment methods. The biological treatment process that occurs in the presence of oxygen (Aerobic process) results the maximum reduction level of BOD and COD. Especially in the Activated Sludge Process (#ASP), the BOD removal is up to 80-95 percent and bacteria removal is up to 90-95%. The type of suitable aeration mechanism working with optimum efficiency plays vital role in the performance of biological treatment. Hence, the food processing effluent from the existing Effluent Treatment plant at CFTRI has been taken for analysis purpose in order to evaluate the efficiency and standardize the operation of aerator since the capacity of ETP of CFTRI is 120 m 3 / day which is almost equal the designed capacity of 100 m 3 / day for this project work. Moreover, the ETP of CFTRI had been designed based on the Activated Sludge treatment Process. The main characters like BOD, COD and pH have been analyzed for the following three main parameters during the project study 1. Temperature of the effluent at morning, noon and evening 2. RPM of the aerator 3. Immersible depth of impeller into the effluent in the aeration tank. By analyzing the results of the above parameters, the characteristics of the effluent and efficiency of the surface aerators are evaluated.