Impact of varying hydraulic retention time for treating distillery effluent in activated sludge system to combat the environmental and health hazards

Abstract

Ethanol-distilleries are the key supporter to the world's economy, but these are moreover one of the major sources of environmental pollution that can impact the human heath if the effluents are not treated in proper manners. Distillery effluents with high biological oxygen demand (BOD) and chemical oxygen demand (COD) contains toxic chemicals which are reported to be of carcinogenic and mutagenic in nature. One of the widely used technology for the distillery wastewater treatment is based on up-flow anaerobic sludge blanket (UASB) technology along with activated sludge process. This technology has fulfilled a need for high efficiency treatment of wastes from various distilleries. With the increasing demands of distillery units and strict guidelines by government agencies for the environment protection, more efforts are required to achieve the zero liquid discharge (ZLD). The research reported in this paper is an effort to perform the in-situ study for evaluating the impact of varying retention times on the efficiency of the condensate Polishing Unit (CPU) based on UASB technology along with activated sludge process for ZLD. The primary objective was to determine pH, BOD and COD after increasing the HRTs in the aeration tank.