上推流厌氧反应器连续干发酵猪粪产沼气试验研究

Continuous Dry Fermentation of Pig Manure Using Up Plug-Flow Type Anaerobic Reactor

为解决猪粪连续干发酵存在的氨抑制和出料难等难题,在温度(25±2)℃、有机负荷为干物质(TS)4.44 g.(L.d)-1的条件下,采用上推流式厌氧反应器(UPAR)对猪粪进行连续干式发酵试验,研究了猪粪干发酵过程的产气情况、氨抑制现象和出料流动性,并考察了上推流厌氧反应器进行猪粪干发酵的可行性.试验采用4种不同TS质量分数(20%、25%、30%、35%)的猪粪作为原料,经160 d的运行.结果表明,进料TS质量分数对发酵过程有很大的影响,4种不同进料TS质量分数稳定的池容产气率分别为2.40、1.73、0.89、0.62 L.(L.d)-1,进料TS质量分数为20%、25%和30%的产气效率明显优于进料TS=35%的产气效率.随着进料TS质量分数从20%增加到35%,氨氮质量浓度>2 300 mg.L-1会出现明显的产气抑制.在进料TS=35%时,氨氮质量浓度能达到3 800 mg.L-1,产气速率相对于进料TS=20%递减74.1%.当进料TS达到35%、出料TS质量分数达到17.1%、流速<0.002 m.s-1时,UPAR不能顺利出料.

To solve the problems of ammonia inhibition and discharging difficulty in continuous dry fermentation of pig manure,under the experimental conditions of temperature of（25±2）℃ and organic loading rate（TS） of 4.44 g·（L·d）-1,a lab-scale up plug-flow type anaerobic reactor（UPAR） was setup to investigate biogas production,ammonia inhibition,effluent liquidity,and the feasibility of continuous dry fermentation of pig manure using up plug-flow type anaerobic reactor.The experiment was operated for 160 days using the pig manure with four different TS mass fractions（20%,25%,30%,35%） as feeding.Results showed that the feeding TS mass fraction exerted a significant influence on the dry fermentation of pig manure;the stable volumetric biogas production rates of four different feeding TS mass fractions were 2.40,1.73,0.89,and 0.62 L·（L·d）-1,respectively;the biogas producing efficiencies of the reactors with feeding TS mass fractions of 20%,25% and 30% were obviously superior to that with feeding TS of 35%.With feeding TS mass fraction increased from 20% to 35%,obvious inhibition to biogas producing occurred when concentration of ammonia nitrogen reached more than 2 300 mg·L-1.When the feeding TS mass fraction was 35%,the concentration of ammonia nitrogen could accumulate to 3 800 mg·L-1 but biogas production rate decreased 74.1% of that with feeding TS of 20%.Additionally,while the feeding TS mass fraction was 35%,the effluent TS mass fraction achieved 17.1%,and the velocity of effluent was less than 0.002 m·s-1,the effluent of UPAR could not be smoothly discharged.