Study On The Utilization Of Nitrogen And Phosphorus In Wastewater By Electrolysis-adsorption

Ammonia and phosphate in water are valuable resources for recycling.At present,the recovery methods of nitrogen（N）,phosphorus（P）in water resources is not much,today.Using struvite（MAP）as the precipitated product is a precipitation method among the promising prospects,The method of the drug dosage is too large and the processing cost is higher.Although this method has a good effect on the removal rate of N,P and MAP recovery.In this experiment.We use the electrolysis of water instead of MAP precipitation in the addition of alkali to magnesium as the anode of electrolysis and produce magnesium ions(Mg²⁺)instead of magnesium salt dosing To solve the disadvantage of the MAP precipitation method is that the treatment cost is high.Firstly,For determined the optimal conditions of the electrolysis experiment,we use the electrolysis experiments were carried out with the simulated N and P ratio of 1:1 and the initial concentration of 100mg/L to experiment.Secondly,We studied the simulated wastewater with initial N,P initial concentration of 100mg/L,200mg/L,400mg/L,600mg/L,800mg/L and 1000mg/L removal in the simulated wastewater.Thirdly,the zeolite adsorption experiment was carried out on the waste water which was not up to the electrolysis treatment,Finally,the electrolysis-induced precipitation and standard struvite were analyzed and compared by infrared spectroscopy and the yield and purity were analyzed.The experimental results show:1.The optimum conditions of the electrolysis experiment were as follows:the electrolysis voltage was 5 V,the electrolysis time was 160 min and the stirring speed was slow.The pH value of the solution was 9.8,and the removal rates of ammonia nitrogen and phosphate were 79.7%and 98.46%,respectively.2.The electrolysis experiments of N,P simulated wastewater with different initial concentrations were carried out.The results showed that the removal rates of N and P were basically the same at all concentrations,and the removal rates of ammonia and nitrogen were about 80%;Phosphate removal rate of 95%to 99%in the optimal experimental conditions.3.The residual concentrations of N and P in the water after the electrolysis were measured.The concentrations of residual nitrogen and phosphate in the residual liquid were 11.8¹87 mg/L and 1.98²6 mg/L,respectively,which could not meet the discharge standard,And the higher the initial concentration of N,P,the higher the concentration after electrolysis.4.The adsorption of N and P on zeolite can be achieved after the zeolite adsorption.The concentration of ammonia and phosphate in the range of 0.68¹8.6 mg/L and 0.41¹.0 mg/L,respectively,The higher the concentration is,the better the ratio of zeolite is,the higher the ratio is 12³6 g/L.5.The infrared spectra showed that the absorption peak of NH⁴⁺,the absorption peak of phosphate and the absorption peak of Mg²⁺appeared obvious trough,which proved that the precipitate produced in this experiment was indeed struvite precipitation,And the purity of struvite is between 95.37%and 99.75%.The higher the initial concentration of N,P is,the more the products are obtained,the yield is 4.6-44.2 g.