Nitrogen recovery by struvite precipitation from anthropogenic nutrient solution

In this study, the factors affecting struvite precipitation performance were experimentally investigated using the actual human urine composite samples. The composite sample was enzyme-hydrolyzed to convert the urea to ammonia. 1:1 dilution of the sample was also used to mimic flush-toilet conditions. The results showed the applicability of struvite precipitation to human urine for nitrogen recovery. High ammonia removal efficiencies up to 95 % were obtained at pH ≥9 for both diluted and undiluted samples. The process also removed more than 80 % organic nitrogen and 70 % COD, at excess doses as well as stoichiometric ones of magnesium and phosphate. Both excess dose applications and dilution yielded ammonia, organic nitrogen and COD removal performances, similar to that of the actual sample.