Experimental Study On Dry Anaerobic Digestion Of Pig Manure

To explore the into different additives’ influences on dry anaerobic digestion of pig manure and obtain a optimum process condition,this experimental paper studied different additive,different added volume,different fermentation concentration,different fermentation temperature and different inoculum concentration on pig manure,using as fermentation raw material.Applying response surface optimization experiment and rigorous analysis,via Design-Expert application,lead to the optimum process condition.The experimental results are as follows:1.The VS gas production rate of anaerobic dry fermentation elevates 22.10 %compared with that of anaerobic wet fermentation with shorter fermentation cycle.2.Cumulative gas production of experimental groups,adding activated carbon,magnet powder and ash content,respectively elevate 28.2 %,10.6% and 12.4 %compared with control groups.And all the three additives can shorter the HRT of dry anaerobic digestion of pig manure.3.Addition of activated carbon in three experimental groups respectively are1 %,5 % and 9 % of dry substance of fermentation system.Their VS gas production rate separately promote 14.33 %,16.93 % and 8.68 %.Furthermore,the more activated carbon is added,the shorter HRT will be.4.Among the three experimental groups with 30 %,40% and 50 % inoculum concentration,the gas production of 40 % group is the best compared with the experimental groups,while the VS production rate of the 30 % group and the 50 %group promoted 10.34 % and 5.85 %.What’s more,the higher inoculation amount is,the shorter HRT will be.5.Among the three experimental groups with 20 %,22 % and 24 % fermentation concentration,the VS production rate of the 24 % group is the highest up to 637 ml/g while the VS Methane production rate of the 20 % group is up to 385 ml/g.The higher fermentation concentration is,the longer HRT will be.6.Among the three experimental groups with 30 ℃,34 ℃ and 38 ℃fermentation temperature,as for VS methane production rate,the 34 ℃ group is up to the highest.The higher gas production is,the shorter HRT will be.Conducting three factors and three levels of response surface optimization experiments on fermentation temperature,inoculum concentration and the amount of activated carbon,adding via Design-Expert app,and taking the gas production rate of the raw material as a response value,we ultimately get the optimum process condition,which is 33.6 ℃ fermentation temperature,40.9 % inoculum concentration and 6.9 %activated carbon addition.Leachate reflux for pig manure raw materials of anaerobic dry fermentation can improve the gas production and methane production of raw materials.And the optimal treatment process with lifting effect is to reflux the percolate once every three days.The optimum conditions of dry anaerobic digestion of pig manure were as follows: fermentation temperature 34 ℃,inoculum size 40 %,activated carbon 7 % of dry matter in fermentation system,leachate refluxing times 3days per time.