Effluent nutrient management and resource recovery in intensive rural industries for the protection of natural waters

Intensive rural industry is developing rapidly in parts of inland Australia . The usually nutrient and salt rich effluent from these sources has tradit ionally been disposed to both land and water bodies. Since direct water dis charge is no longer permitted, a challenge now exists when applying effluen t to land especially where the rate of application exceeds crop requirement s. Effluent of high volume and concentration of nutrients and/or salts can easily contaminate land and water resources. Predicting the optimum rate of land application of effluent is complicated by the physical, chemical and biological properties of soils. This paper addresses the characteristics of effluents from various intensiv e rural industries and their potential environmental impacts when irrigated to agricultural land in New South Wales, Australia. To assess the environm ental sustainability of effluent reuse in land application, a mathematical model (ERIM) has been developed based on a monthly water balance. ERIM incl udes historical rainfall and evaporation; the amount of nitrogen and phosph orus introduced; their yearly removal by plants to be grown; amount of appl ied organic matter; and water holding capacity of soil. (C) 1999 IAWQ Publi shed by Elsevier Science Ltd. All rights reserved.