Reduction potential of greenhouse gas emission from swine wastewater purification treatment by using a low-protein diet supplemented with synthetic amino acids

Abstract

For NH₃, N₂O and CH₄ emission regulation of swine wastewater purification process, the low crude protein (Low-CP) diet was supplemented with lysine, methionine, threonine and tryptophan at levels sufficient to meet their requirements, in our trial. Fifty-six days of comparative wastewater purification experiment was conducted against ordinary diet, as a control (CONT). Comparing to CONT group, the amount of excreted urine and N in urine was reduced by 33.6% and 57.6% in the Low-CP group, respectively. There were no differences in daily weight gain and N retention between CONT and LOW-CP diet. According to wastewater treatment examination, BOD removal efficiency of CONT and LOW-CP were 55.8% and 64.2%, respectively. Nitrogen removal efficiency of CONT and LOW-CP were 62.1% and 61.7%, respectively. During the wastewater treatment, NH₃ and N₂O emission were reduced in LOW-CP 57.3% and 89.3%, respectively. For the pollutant nitrogen removal from swine barn, the dietary protein reduction on N excretion is beneficial but also to decrease Greenhouse gas emission practically.