Effects Of Different Substrate Concentration And Additive Combination On The Maturity Extent And Fertilizer Efficiency Of Anaerobic Fermentation Of Pig Manure

In recent years,the scale of farms in China is gradually expanding,the waste generated during the breeding process is gradually increasing and more concentrated,anaerobic fermentation technology has always been seen as an effective way to resolve conflicts between farming and the environment.Traditional anaerobic fermentation technology has strict requirements on fermentation temperature,fermentation substrate and fermentation pH,the effective use of biogas,biogas slurry and biogas residue generated during anaerobic fermentation has always been a problem that plagues people.The test is aimed at the generation of greenhouse gases in the anaerobic fermentation process,the large nutrient loss of the biogas residue and the biogas slurry,and the low efficiency of the biogas residue and the biogas slurry,this test aims to reduce biogas emissions,reduce the nutrient loss of biogas slurry and biogas residue,and improve the fertilizer efficiency of biogas slurry and biogas residue,this experiment explored the effects of different substrate concentrations and additive combinations on biogas production and various physical and chemical indicators of biogas residue and biogas slurry during anaerobic fermentation,based on the trends of these indicators,determine the optimal substrate concentration and additive combination and the optimal fermentation time.The main findings are as follows:(1)Under the condition of low temperature anaerobic fermentation,the increase of substrate concentration can significantly reduce the biogas emission during anaerobic fermentation,when the substrate concentration increased from 3% to 9%,the biogas emission is significantly reduced by 54.30%.(2)The increase of substrate concentration can significantly reduce the nutrient loss of biogas slurry and biogas residue in low temperature anaerobic fermentation.When the substrate concentration increases from 3% to 9%,the total nitrogen loss rate of biogas residue decreases from 16.58% to 9.58%.The total nitrogen content of the biogas slurry changed from a loss of 35.61% to an increase of 27.73%,and the total organic carbon loss rate of the biogas residue decreased from 18.65% to 13.19%.(3)The increase of substrate concentration can significantly improve the fertilizer efficiency of biogas slurry and biogas residue in low-temperature anaerobic fermentation,but the fertilizer efficiency of biogas slurry still does not reach the standard in NY/T2596-2014.When the substrate concentration increased from 3% to 9%,the total organic carbon,total phosphorus,total nitrogen,ammonia nitrogen,fulvic acid,and humic acid in the fermentation system were significantly increased.(4)The additives under the design conditions of this experiment did not have a significant effect on low temperature anaerobic fermentation.(5)When the substrate concentration was 9% and the fermentation time was 32 days,the highest fertilizer efficiency index and the maturity index under the experimental conditions were obtained.