Removal of Phosphorus in Rubber Wastewater – Design of Experiment for the Struvite Crystallization Reaction

Abstract

Recovering struvite crystal is one of the most interesting methods for removing phosphorus from wastewater to produce fertilizer. Phosphorus is removed from wastewater streams to prevent the ecologically harmful effects of eutrophication in receiving natural, so the recovery and reuse of phosphorus in rubber wastewater by struvite precipitation not only reduces the effects of phosphorus for the environment where the product MAP (Magnesium Ammonium Phosphate) is also a slow release fertilizer is very useful for agriculture. During the reaction process taking place, the parameters of pH, Mg²⁺/PO₄^3- ratio and NH₄⁺/PO₄^3- ratio gate the large influence on the formation of struvite. The design of experiment had been carried out using three factors based, multi-factorized experimental equation was. From the experimental equation, the experimental had been optimized for three factors. The optimization level of the parameters were determined as 9.0 for the pH, 1.25 for ratio of Mg²⁺/PO₄^3- and 4.35 for ratio of NH₄⁺/PO₄^3-. The obtained precipitation volume with optimum parameters was 0.3401 g/300 mL of rubber waste