Phosphorous Recovery Technology in Conjunction with Dairy Anaerobic Digestion

Phosphorous (P) is a non-renewable resource and an important non-substitutable macronutrient, which exists in nature as phosphates in various inorganic or organic forms. Agriculture, through its reliance on inorganic fertilizers, is the primary user of commercially-produced P, and there is concern that current exploitation is unsustainable. Total annual global production is currently 20 million tons of P, derived from approximately 140 million tons of rock concentrates (IFA, 2002; Rockstrom et al., 2009). Nearly all the P used globally is mined from a relatively small number of commercially-exploitable deposits, and it has been estimated that the global economic P reserves may last only about 100 years at the current rate of extraction (Driver et al, 1999).