Effect of Using Rice Husk Char as an Additive on Phosphate Recovery from Swine Wastewater by Magnesium Metal Corrosion

Abstract

The recovery of phosphate from swine wastewater is highly significant in order to alleviate eutrophication in aquatic ecosystems, and the increasing scarcity in phosphorus resources. This study reports on a strategy to recover phosphate from swine wastewater using rice husk char as an additive via magnesium metal corrosion. The results demonstrated high levels of recovery efficiency at relatively low cost. When the mass ratio of rice husk char to magnesium was 2:1, the pH of this solution increased to 9.75, and the phosphate recovery efficiency from real swine wastewater reached 96.80% at a Reynolds number of 13931 without aeration. Evaluation of economic feasibility revealed that the proposed method was $0.79 kg−1 of PO4-P. Approximately 57.98% of the cost may be saved compared with the use of magnesium metal pellets coupled with graphite pellets.