| In the domestic sewage,the excrement volume accounts for about 1-2%of the volume,but it contains about 97%of the nitrogen and about 90%of the phosphorus.In these excreta,urine has the characteristics of high nitrogen and phosphorus,however nitrogen and phosphorus are important elements of causing water eutrophication.Compared with the traditional end-mixed wastewater treatment method,it is more easier to collect and process individually the urine which has small volume and high concentration nutrient elements to resource the nutrient elements and control the pollutants.Thus the concept of source separation is formed.The source separation method has strong water saving ability.Compared with the traditional water saving toilets,the water consuming separated toilet can also save about 70%of flushing water.There are many ways to deal with urine after source separation,which can be divided into three broad categories:physical,chemical and biochemical methods.The physical method only aims at ammonia nitrogen,it mainly has ammonia stripping technology;Chemical method has varieties of treatment methods,but because of the need to adding chemicals,it will cause secondary pollution.There are many kinds of biochemical methods,but a lot of sludge will be produced after biochemical treatment,and the sludge needs further treatment.From the perspective of recycling and saving energy,the basic purpose of this paper is to solve the environmental pollution,waste of nutrient resources in excrement and urine,and the recycling of water.n this experiment,a self-made electrochemical device with the function of flow field and electric field coupled with a magnesium source reactor was used to synthesize magnesium ammonium phosphate(MAP)by electrolysis separation of nutrients N and P in urine.This experiment has realized the second flush reuse of water and the synthesis of valuable by-products of nitrogen and phosphorus.In this paper,the effects of voltage,electrolysis time,position of magnesium source reactor,speed ratio of two pole flow,washing water in toilet and other technical parameters on the separation of N and P were investigated,and the properties of the synthetic by-products MAP were analyzed.The results show that 18 V is the optimal treatment voltage condition for the self installed equipment through the experimental study on the additional voltage and the economic feasibility.At 18V voltage,the treatment effect gradually improves with time.When deionized water is used as washing water,the removal efficiency of phosphorus can reach 48%after 7 hours treatment.If the magnesium source reactor is transferred from the cathode outlet to the anode outlet,and the removal ability of N and P is strengthened.When the water flow ratio of cathod to anode is 60:1,the recovery rate of cathod phosphorus is above 70%,the recovery rate of the anode is over 90%,it also has a certain removal effect on ammonia nitrogen,As time goes on,the water temperature increases and the reaction is promoted,the treatment effect is more obvious.With deionized water,tap water or tap water with sea water are used as cleaning water,the removal rate of P at 5 hours was 28%,33%and 60%respectively.It is indicated that the running water with tap water or the tap water with sea water can obviously improve the processing efficiency.After treatment,the solid product is white precipitation,and it is easy to precipitate.After one night of water deposition,the turbidity of water sample drops from 22NTU to near ONTU.Meanwhile,the self-made electrochemical device also has good bactericidal effect. |
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