Experiment On Removing Nitrogen And Phosphorus Of Urine

Urine is rich in nitrogen and phosphorus,respectively occupies 80% and 50% in sewage. If nitrogen and phosphorus of urine can be removed, it will have important economic value on sewage treatment. In this paper, studying the characteristics of fresh urine hydrolysis is the basis of removing phosphorus of urine by using reverse osmosis water, and doing the analysis of precipitation product and characterization of the elements can be confirmed the specific precipitation product. NH4+-N of urine can be removed by using micro algae. Drawing the following conclusions:(1)Fresh urine is acidic or neutral. pH is between 6.58～7.30. Concentration of NH4+-N is between 1000～1500mg/L. Concentration of TP is between 400～500mg/L. The experiment results show that:with the hydrolysis time, concentration of NH4+-N in the urine is increasing rapidly. Concentration of NH4+-N can be reached to 5000～5500 mg/L on the eighth day. Concentration of TP is decreasing with the hydrolysis time and eventually stabilizes 300～320 mg/L. Temperature has certain influence on the hydrolysis of urine, the higher the temperature is, the lower pH and TP of urine are and the higher the NH4+-N is. The initial pH of the urine has certain influence, pH of urine approaches gradually to 9.00 on the eighth day. Concentration of TP and concentration of NH4+-N change slightly.(2)The experiment of reverse osmosis concentrating phosphorus of urine, examines the factors on hydrolysis time of urine, pH, stirring rate and ratio in urine and RO concentrated water.The experiment results show that,when urine hydrolysis time is 8d, ratio of RO water and urine volume is 1:1.25, pH value is 9.50, the stirring speed is 80 r/min, precipitation time is 60min, phosphorus removed efficiency can be reached 90.0%. Using RO water can achieve the goal of removing phosphorus of urine.(3)The experiment of precipitation of analysis shows that, the magnesium by using RO water removing phosphorus are mainly calcic magnesium and magnesic precipitation. The main precipitation products include MAP, Ca3(PO3)2 and CaCO3, including a small amount of Mg3(PO4)2. MAP is prismatic. Ca3(PO3)2 and CaCO3 are irregular spherical.(4)Studying the growth discipline of micro algae in urine. The experiment results show that,it is the best condition for growth of micro algae when vaccination is OD68s(0.143),diluted multiples is 15, illumination time is16h/d, temperature is 25℃, light intensity is 20μmol-2s-1(5)Studying the removal efficiency of NH4+-N by using the micro algae in urine. The experiment results show that, Micro algae removal efficiency of NH4+-N in urine can be up to 64.8% in the most suitable condition for micro algae growth. Removal value of NH4+-N in the solution and added value of algal of nitrogen cell dry weight are basically identical.