膨润土对鸡粪序批式厌氧消化特性的影响

Enhanced Anaerobic Digestion of Chicken Manure by Bentonite Addition

为考察外源添加物——膨润土对鸡粪厌氧消化特性的影响在中温[（35±1）℃]条件下,采用L_8（2^3）正交试验设计,考察了膨润土添加量（w,以干基计,下同）、鸡粪VS（挥发性固体）添加量、厌氧消化污泥接种量对鸡粪厌氧消化过程中产气、pH、氨氮形态、EC（电导率）等的影响.结果表明：添加1.5%和3.0%的膨润土均能显著提高鸡粪VS产CH_4量,并且在高鸡粪添加量情况下达到极显著水平（P〈0.01）;当膨润土添加量为3.0%、厌氧消化污泥接种量为20%时,VS累积产CH_4量达到301.92 mL/g,比对照组（160.76 mL/g）提高了87.80%;当鸡粪VS添加量相同时添加1.5%和3.0%的膨润土均能极显著地降低消化料液的ρ（TAN）（TAN为总氨氮）（P〈0.01）,并且可以减少鸡粪厌氧消化过程中ρ（FAN）（FAN为游离氨）的剧烈变化;添加膨润土还能极显著地降低鸡粪厌氧消化料液的EC.研究显示添加膨润土有利于缓解鸡粪厌氧消化过程中氨氮抑制,提高系统稳定性,并可显著改善厌氧消化整体性能.

External bentonite addition was proposed to alleviate ammonia inhibition associated with anaerobic digestion of chicken manure.Batch experiments based on orthogonal design L_8（2^3） were conducted to investigate the effects of bentonite dosage（wt.%,on a dry weight basis）,manure dosage（g VS） and inoculum concentration（%,V/V） on biogas production,pH,electrical conductivity and ammonia speciation during chicken manure degradation at the mesophilic temperature（35 ± 1） ℃.The results showed that methane production was significantly enhanced when 1.5%and 3.0%dosages of bentonite were added,particularly at the high manure dosage（P〈0.01）.For example,in experiments with 3.0%dosage of bentonite and 20%inoculum concentration,the cumulative methane production could reach up to 301.92 mL/g,which was 87.8%greater than that of the control experiment（160.76 mL/g）.Significant decreases in total ammonia-nitrogen（TAN） concentration and electrical conductivity were also observed in experiments with 1.5%and3.0%dosages of bentonite addition（P〈0.01）;the drastic variation of free ammonia concentration was avoided as well.In conclusion,bentonite addition could effectively alleviate ammonia inhibition,resulting in more stable and enhanced anaerobic digestion performance of chicken manure.