Evaluation of Dairy Effluent Treatment Efficiency in Aerated Sequential Batch Reactor - A Numerical Approach

Abstract

The dairy industry is considered as one of the major water-consuming industries in the world and the waste generated from the dairy industry severely contaminates the environment. Dairy wastewater has high chemical oxygen demand (COD), biological oxygen demand (BOD), and nutrient concentration. Therefore, dairy wastewater treatment has been mandatory before its discharge into water bodies. Sequential batch reactor (SBR) overcome these problems through excellent BOD/COD removal and is highly flexible. This work aims to study about the removal of organic contents from dairy effluent using a Sequential Batch Reactor (SBR). A Sequential Batch Reactor was designed and manufactured with a 45 L capacity. Dairy effluent was collected from Milma Dairy, Kollam and were analyzed the characteristics such as BOD and COD. It was observed that the samples procured high BOD, COD, and Suspended solids (SS) concentrations. The potentiality of SBR for the removal of organic matter from dairy effluent was studied in detail. Batch kinetic studies were carried out analytically for various values of cycle time (Tc). SBR was optimized by varying operational parameters like flow rate (Q) and Tc. The nature of treatment efficiency with varying flowrate and Tc was examined graphically and observed that efficiency improved as the Tc increases due to increase in the reaction time. On increasing influent flow rate, the treatment efficiency was found to decreases as the amount of organic matter entering the tank increases. HRT (hydraulic retention time) of 8.1 h with a flowrate of 0.09403 L/min, Tc of 6h was sufficient to remove 33.8 g/d BOD thereby giving a treatment efficiency of 86.46%.

Keywords: Dairy wastewater, Sequential Batch Reactor (SBR), Hydraulic Retention Time (HRT), Activated Sludge process (ASP)