Abstract: To efficiently remove  nitrogen and phosphorus from highly concentrated  livestock and poultry wastewater,an MAP(magnesium-ammonium-phosphate)sedimentation method coupled with ultrasonic technology is used.Studies have been done to explore optimal conditions for use of the method through controlling and regulating pH,n(Mg²⁺):n(NH₄⁺):n(PO₄^3-)and duration of the reaction.Results show that the MAP sedimentation method may achieve its best effect within the first 10 min of reaction,removing 95.10% of ammonia nitrogen and 97.10% of ammonia nitrogen and 97.40% of phosphorates in wastewater,when pH is controlled at 9.5,and n(Mg²⁺):n(NH₄⁺):n(PO₄^3-)at 1.2:1:1.Moreover,when the method is coupled with 60 W ultrasonic irradiation for 6 hours and increased aeration of 200L·h^-1,its N removing efficiency can be further improved up to 98%.

Key words: magnesium-ammonium-phosphate, poultry feces, nitrogen and phosphorus removal, ultrasonic