Optimized ammonium sulphate recovery by stripping-scrubbing sequence system from compost leachate at mesophilic temperatures

Abstract

This study focused on the development of a stripping process for recovering nitrogen from compost leachate. Several experiments were carried out to identify the optimum conditions of temperature, airflow rate and pH that provide effective recovery of nitrogen from the leachate. The most energy and chemical saving experimental condition were found out to be at 40 °C, an airflow rate of 1 L/min and a pH of 10.5. A stripping efficiency of about 94% was observed upon the use of an air flow rate of 1 L/min and a 71% recovery in sulphuric acid to finally obtain ammonium sulphate. The experiment was performed using a leachate volume of 500 mL, with an NH4+ concentration of 600 mg/L, and during the absorption, the total ammonium was recovered as 214 mg/150 mL of sulphuric acid solution (2% v/v), which makes a total recovery of 71% of initial ammonium concentration. Overall, it is reported that 1.5 g of ammonium sulphate could be extracted from the processing (stripping and absorption) of 1 L of raw leachate. © 2022