Farm/Industrial/Municipal Waste: Prospects of Nutrient (Phosphorus) Recovery

External supply of plant nutrients is a must to achieve intensification of agricultural sector, thereby meeting food demand of growing global population. However, non-substitutable nutrient like phosphorus (P) with finite natural reserve makes recovery of it a progressively attractive option from alternative waste sources. P recovery method identifies production of P-enriched mineral as mainstream option through technically and economically viable recovery processes. In this context, recovery of struvite (MgNH4PO4.6H2O), an alternative P fertiliser from waste streams of farm, municipal and industrial origin, remains a research focus, as considerable fraction of P ends up in these P sinks. The recovery process creates added benefits of quality control of nutrient-laden waste before environmental disposal and reduction of waste volume. In this study, we evaluate some potential P wastes for struvite recovery, in terms of some compositional parameters (orthophosphate, ammonium, calcium). Among these sources, anaerobically digested waste represents suitable considerations for struvite recovery because of retention of nutrient with increased plant availability. Study assessed the potential of anaerobic digestate of different climatic zones (India and the UK) as prospective P source by determining their chemical composition. Through a range of treatments (acidification and chelating agent), P availability was shown to be elevated, indicating its further enhanced potential recovery.