MANAGEMENT OF DAIRY WASTE - A LOW-COST TREATMENT SYSTEM USING PHOSPHORUS-ADSORBING MATERIALS

Dairy wastes are a source of nutrient pollution of surface and ground waters in high rainfall areas of south west Western Australia. Many of the state's 546 dairies are sited over soils that are either sandy, leading to pollution of ground waters, or clayey, causing reductions in surface water quality. Awareness of the environmental implications of their activities is motivating dairy farmers to join Land Conservation District Committees, where water quality improvement is a primary goal. A low cost treatment system has been designed to reduce the water pollution potential of dairy waste. It incorporates three stages: a sump in which anaerobic digestion occurs; an aerobic vegetated filter with a base of permeable phosphorus-absorbing material; and an irrigated plantation or crop using water that has passed through the system. This paper describes the theoretical background to the design.