Kinetic Study Of Semi-continuous Anaerobic Co-digestion With Kitchen Waste And Pig Waste

As the economy developing and improvment of living standards, Kitchen waste, animal manure and other biomass waste will heavily increase. Through biomass waste disposal has becomed a pressing problem, it also provides a rich resource of waste recycling. The anaerobic co-digestion of kitchen waste and pig waste can not only maximize the treatment of organic components and reduce pollution, but also produce biogas and recycle energy, which makes harmless and recycling waste become a reality.In this experiment, the anaerobic co-digestion of kitchen waste and pig waste was conducted in a CSTR anaerobic reactor by a semi-continuous mode. The results showed that:with gradually increasing organic loading rate (OLR), before acidification pH value was maintained at 7.1 and VFA concentration was stable at 900-1400mg/L in addition to the fluctuation during the early experiment. To 66 days of digestion, when pH value dropped to 6.7 and VFA concentration increased to 5208mg/L, test appeared acidification. The maximum daily gas production, the maximum daily methane production and the maximum value of biogas yield under OLR of 0.75gVS/L.d were about 7850mL,4357mL and 0.78L/gVS, respectively. The average CH4 content were about 38%,51% and 42% at different OLRs. The anaerobic digestion achieved balance and optimum performance under OLR of 0.75gVS/L.d. Gas production process of anaerobic digestion conformed first-level kinetic equation y1=w(1-e-k1t)=0.8035×(1-e-0.2067t) under OLR of 0.75gVS/L.d, the corresponding kinetic parameters k1=0.2067. Use this model to estimate the maximum value of biogas yield w as 0.8035L/gVS, with the experimental relative error as 3.0%. This study provided a new way to build a kinetic model of anaerobic co-digestion of biomass waste.