The Potential of Acid Hydrolysis as Pre-Treatment for Improved Nutrient Recovery from Domestic Wastewater

Abstract

Domestic wastewaters have a significant concentration of nutrients that can be utilised as alternative sources of phosphorus and nitrogen for agriculture applications. Chemical precipitation is one of the processes found to be an efficient way for nutrient recovery from various wastewater feedstock. However, not all nutrients are in a form that can be readily recovered. Therefore, a pre-treatment process may be necessary for an efficient recovery of nitrogen and phosphorus. In this research, acid hydrolysis was performed as pre-treatment to release phosphorus from synthetic septage into soluble forms for the subsequent precipitation as struvite (MgNH₄PO₄·6H₂O) which is known as a slow-release fertiliser for application in agriculture. Results show that acid hydrolysis increases the phosphate concentration (PO₄-P) to 148.07 ± 1.78 from 61.50 ± 0.07 mg/L, showing the potential of hydrolysis as pre-treatment to efficiently recover nutrients in the form of struvite. The result can inform further research to develop efficient processes for the recovery of nutrients from domestic wastewater.