膨润土对鸡粪序批式厌氧消化特性的影响

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L₈(23)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CH₄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CH₄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. 

Enhanced Anaerobic Digestion of Chicken Manure by Bentonite Addition

Abstract:External bentonite addition was proposed to alleviate ammonia inhibition associated with anaerobic digestion of chicken manure. Batch experiments based on orthogonal design L₈ (23) 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% and 3.0% 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.