新型两相一体厌氧消化反应器处理餐厨垃圾中试研究

A pilot study on integrated two-stage anaerobic digestion of food waste in an innovative dual-cylinder reactor

针对餐厨垃圾厌氧消化过程易发生挥发性脂肪酸(VFAs)的积累,系统难以稳定高效运行等问题,本研究设计制造了一套中试规模的新型双环嵌套式两相一体厌氧反应器,采用双环嵌套式结构,在反应器内部将内环的产酸阶段与外环的产甲烷阶段分离.反应器共运行184d,初始负荷为60kg/d,运行阶段阶梯式提高负荷,最高达到180kg/d.结果表明,该新型反应器产气与有机固体去除效率高,稳定性好.在稳定运行阶段,有机负荷为3.0kgVS/(m^3·d),容积产气率平均达到1.69m^3/(m^3·d),最高为2.72m^3/(m^3·d),平均负荷产气率为0.57m^3/(kgVS·d),有机固体去除率达77.2%;由于内外环相分离作用,外环p H值相比内环高约0.3～0.4,外环挥发性脂肪酸(VFAs)和溶解性化学需氧量(sCOD)平均浓度相比内环分别降低25%和23%.双环嵌套式反应器实现了产酸和产甲烷阶段分离的作用,内环产酸相很好地完成了水解和酸化步骤,同时减轻产甲烷相受到酸积累的冲击,对反应器稳定运行起到关键作用.

In this study,an innovative integrated two-stage(ITS)anaerobic bioreactor was designed and constructed in pilot scale.The integrated reactor used the dual-cylinder configuration to separate the acidogenic stage in inner cylinder with the methanogenic stage in outer cylinder.The reactor was operated for 184days treating food waste with elevated organic loading rates(OLR).The ITS reactor showed high efficiency and stability.In the stable operation phases,the organic load was 3.0kgVS/(m3·d),volumetric gas production rate reached an average of 1.69m3/(m3·d),and highest value is up to 2.72m3/(m3·d);the gas production rate was 0.57m3/(kgVS·d),and the organic solids removal rate was 77.2%.Due to phase separation effect,pH value of outer cylinder was about 0.3~0.4unit higher than that of inner cylinder,the average volatile fatty acids(VFAs)and soluble chemical oxygen demand(sCOD)concentration of outer cylinder was 25%and 23%lower than that of inner cylinder,respectively.The integrated two-stage(ITS)anaerobic reactor realized the separation of acidogenic and methanogenic phases in one reactor.The inner acidogenic phase performed the hydrolysis and acidogenic steps and reduces the impact of acid accumulation on the outer methanogenic phase,which played a key role in the stable operation of the reactor.