Factors affecting nutrient solubilization from sewage sludge using microwave-enhanced advanced oxidation process.

A microwave-enhanced advanced oxidation process using hydrogen peroxide (MW-H2O2-AOP) was used for the solubilization of phosphate and ammonia from secondary municipal sludge. Two sets of experiments were performed to determine the factors affecting nutrient solubilization from sewage sludge. Four factors--microwave heating temperature, heating time, hydrogen peroxide treatment, and sulphuric acid treatment--were incorporated into a screening design to determine which factors were significant for maximizing nutrient solubilization. For phosphorus, the three most significant factors, following the order of significance, were (i) microwave heating temperature, (ii) the combined effect of microwave heating temperature and hydrogen peroxide hydrogen peroxide addition, (iii) microwave heating temperature, and (iv) sulphuric acid addition.