| Anaerobic digestion technology is becoming mature and has great commercial potential to deal with organic wastes.But sometimes organic acid accumulation caused by ammonia inhibition has led to operation failur-e when high nitrogen materials such as animal waste is used in the industr ial biogas plant.Therefore improving methane production and operation st-ability is a key problem neededto be solved urgently in the process of biog as industrial development.This project combined with the National Natural Science Foundation of China?51376121?"Anaerobic digestion of livestock and poultry manure biogas toxicity and detoxification mechanism",intended to be added by adding zeolite and biochar method to alleviate ammonia inhibition during the anaerobic fermentation of chicken manure Problems,improve the stability of gas production,and provide practical reference for the large scale biogas production of agricultural organic waste.Different volume fraction of zeolites?2.5%?5%?10%?0%;on working volume basis?were added to the biochemical methane potential?BMP?system of chicken manure.The effects of zeolites on AD performance at 35±1oC were investigated.The results showed that the total yield of biogas reaches maximum?3340 mL?when the concentration of zeolite was 10%.At the 21st day,the experimental group with 5%zeolite had the maximum CH4 content of 73.06%,which was 4.86%higher than that of the control.Three classical kinetic models including first-order kinetics,Transfer function model and Cone models were chosen to describe the methane production kinetics from manures.The Cone model?R2:0.9910–0.9974?fitted to the experiment data the best.Different dosages of biochar?2.5%?5%?10%?0%?were added to the biochemical methane potential?BMP?system of chicken manure.The effects of biochar on AD performance at 35±1oC were investigated.The results showed that when the added amount of biochar was 10%,the total gas production was the largest,reaching 3133 mL.At the end of the fermentation,the concentration of ammonia nitrogen in the experimental group was 2.5%,5%and 10%respectively,and the ammonia nitrogen concentrations in the experimental group were 1822,1707and1672 mg·L-1,respectively.Compared with the control group,the ammonia nitrogen concentration decreased by 8.99%and 14.73%And 16.48%.The first-order dynamic model,the transfer model and the Cone model are used to analyze the kinetics of cumulative gas production.The Cone model has the highest fitting degree with the actual cumulative gas production rate?R2:0.9837-0.9964?.In the experiment of co-fermentation of biogas produced by chicken manure with added zeolite,the total organic load of 32 gVS/L was used as reference to explore the co-fermentation of chicken pomace apple pomace with different volume fraction(5%,10%and 20%Impact of biogas production characteristics.When the proportion of chicken manure and apple raw material was 1:0,the final cumulative gas yield of the experimental group with 20%zeolite was 9463 mL;the concentration of ammonia nitrogen in the control group was 3321 mg·L-1 at the end of fermentation,the amount of zeolite was 20%The ammonia nitrogen concentration in the experimental group was 2011 mg·L-1,and the ammonia nitrogen removal rate was 39.45%.The final cumulative gas production was 11099 mL in the test group with 2:1 chicken manure and5%zeolite,and the concentration of ammonia nitrogen in the control group was 2371 mg·L-1 at the end of the fermentation.Adding 5%,10%and 20%)were 2093,1708 and 1881 mg·L-1,respectively,and ammonia nitrogen concentrations decreased by 11.72%,27.96%and 20.76%respectively.The final cumulative gas production of the test group with 20%zeolite added with 1:1 chicken manure and apple was 15068 mL.The ammonia nitrogen concentration of the control group was 1660 mg·L-1 at the end of fermentation,and the addition of zeolite was 20%The concentration of ammonia nitrogen in the group was 1261 mg·L-1 and the concentration of ammonia nitrogen in the group was decreased by 24.04%. |
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