猪粪干式厌氧消化中试试验研究

A Pilot Study on Dry Anaerobic Digestion of Swine Manure

试验采用牛粪消化液为接种物,在中温(36℃)条件下,对猪粪进行了干式厌氧消化中试试验。结果表明,随着进料量由300 kg·d^(-1)提高到450 kg·d^(-1),系统表现出了较好的稳定性,沼气产量为30~35m3·d^(-1),甲烷含量在57%~62%范围内,含水率下降到81%~82%,VS下降到71%~72%,VS去除率在40%左右,p H值在7.98~8.20范围内,碱度由15000 mg·L^(-1)升高到23000 mg·L^(-1)。随着试验的进行,系统氨氮浓度不断增加,为了防止氨氮抑制情况的发生,从第42天开始对出料进行固液分离,只回流沼渣,最后氨氮浓度稳定在5000 mg·L^(-1)左右,游离氨浓度在750 mg·L^(-1)左右,厌氧消化系统没有出现明显的抑制现象。但就产气情况来看,随着进料量的提高,产气量并没有上升,系统现阶段处于抑制平衡状态。

A pilot experiment of swine manure dry anaerobic digestion was carried out in a 24 m3digester under mesophilic （36℃） condition, and the digestion slurry of cow manure was used as inoculums. The results showed that, as the influent increased from 300 kg ·d^-1 to 450 kg ·d^- 1, the system showed a good stability with a biogas production of 30 - 35 m3 · d-1. The methane content was 57% -62% , moisture content dropped to 81% ～ 82 % , VS content dropped to 71% -72 % , VS degradation rate was about 40% , and the alkalinity increased from 15000 mg · d^-1 to 23000 mg · d^-1. A- long with the experiment went on, the ammonia nitrogen concentration was increasing. In order to prevent the occur of am- monia nitrogen inhibition, the solid-liquid separation of effluent was conducted from the 42nd day, and only biogas residue was return to the digester. Finally, the ammonia nitrogen concentration was kept around 5000 mg · d^- 1, and free ammonia concentration was about 750 mg · d^-1 , and no inhibition phenomena occured in the anaerobic system. Later on, the in- creasing of influent could not increase the biogas production, which showed the system was in the stage of inhibition bal- ance.