Utilisation of fish waste bones ash for struvite precipitation in actual landfill leachate

Abstract

Struvite (MgNH4PO4.6H2O, MAP) precipitation is an effective method for the pre-treatment of landfill leachate. Recently, research trend is directed to introduce new sources of phosphorus (P), in order to improve the sustainability of MAP technology. The current study investigated the effectiveness of fish waste bones ash as an alternative source of P for MAP recovery in actual landfill leachate. The P-rich solution, extracted from fish waste bones ash, was mixed with magnesium oxide (MgO) before applying the Mg-P mixture to leachate samples. The experimental results showed that chemical oxygen demand (COD), total suspended solids (TSS), colour and turbidity were reduced with efficiencies of more than 31%, 32%, 51% and 37%, respectively. In addition, around 70% of ammonium-nitrogen (NH4-N) was recovered in the form of struvite. The presence of struvite crystals in harvested precipitates was confirmed by X-ray diffractometry (XRD) test. Furthermore, utilisation of Mg-P mixture was considerably competent compared to conventional reagents.