Method for recovering nitrogen and phosphorous from urine

Abstract

The invention belongs to the technical field of separation of domestic sewage sources and relates to a chemical method for urine treatment and recovery of nutrient elements, in particular to a method for recovering nitrogen and phosphorous from urine. The method comprises the following steps of: collecting fresh urine and then naturally covering and storing, and recovering nitrogen and phosphorus after the pH reaches above 9, wherein the pH can raise to 9 after the urine is stored for about 10 days according to the difference of seasons and environment temperatures, and the pH monitoring is subjected to the storage process; sampling and detecting the NH4+-N concentration and the PO43--P concentration, feeding Na2HPO4 and MgCl2 according to mol ratio of n(Mg): n(P): n(N) of 1.3: 1: 1, controlling the stirring speed of 100r / min and the reaction time of 10min, precipitating for 1h and then separating supernate to obtain the MAP (Magnesium Ammonium Phosphate) precipitate. In the invention, the phosphate and magnesium salts are fed according to certain mol ratio in accordance with the NH4<+>-N concentration and the PO4<3->-P concentration after the urine is hydrolyzed, the nitrogen and the phosphorus are furthest recovered in an MAP precipitate way by reasonably controlling reaction conditions so that the nitrogen and phosphorus contents are greatly reduced, and the recovery rate of the nitrogen and the phosphorus can reach up to about 95 percent.

Description

technical field [0001] The invention belongs to the technical field of domestic sewage source separation, and relates to a chemical method for urine treatment and nutrient element recovery, in particular to a method for recovering nitrogen and phosphorus in urine. Background technique [0002] Nitrogen and phosphorus in wastewater are important elements that cause eutrophication in lakes and closed coastal seas, but are also important industrial and agricultural resources; therefore, removing and recovering nitrogen and phosphorus from different wastewater can not only protect the environment The purpose of energy recovery and utilization can also be achieved, and its related recovery technology has attracted more and more attention; the concentration of nitrogen and phosphorus in urban sewage is usually low, and it is difficult and uneconomical to directly recover from it; human urine Medium nitrogen and phosphorus account for about 80% and 50% of the nitrogen and phosphoru...

AI Technical Summary

Problems solved by technology

The results showed that Mg / PO 4 3- -P molar ratio is an important operating parameter. When the molar ratio exceeds 1.3:1, the recovery rate of phosphorus exceeds 95%, and the remaining PO in the supernatant 4 3- -P concentration is less than 10mg / L, and increasing the reaction pH cannot significantly increase the recovery rate of phosphorus