Wastewater management in a dairy farm

Field sampling and laboratory experimentation were conducted on wastewater effluent generated at a dairy farm in order to characterise the wastewater, evaluate existing primary treatment facilities, and examine an appropriate wastewater treatment system to produce good quality effluents. It has been found that the farm contributes effluents containing considerable loads of organics, solids and nutrient pollutants. Existing treatment facilities which are limited to batch-operated primary settling tanks, are not capable of producing good quality effluent. Experimentation on an aerobic, suspended growth, biological system using sequencing batch reactors (SBR) indicated that the pollutant loads in the primary-treated effluent could be substantially reduced. The study showed that a wastewater treatment system involving primary settling tanks combined with additional aerobic biological treatment is capable of removing about 94% COD and 96% SS from the farm effluents. This system could be easily integrated and coordinated with existing facilities. A wastewater management scheme has been proposed to include waste minimisation, waste treatment and effluent reuse in irrigation. (C) 1996 IAWQ. Published by Elsevier Science Ltd.