382 / 2018-08-14 15:24:26

Study on the sludge anaerobic co-digestion with biomass straw and the different components of biomass straw

全体主题 > 生物质燃气

The co-digestion of sewage sludge with biomass straw is a promising technology which can improving the performance of anaerobic digestion system.However, the anaerobic co-digestion of sewage sludge with different componets of straw (cellulose, hemicellulose, lignin) has not been studied. This work investigated the methane production by anaerobic co-digestion of mixed sludge with two different biomass straw (wheat straw, corn stalk) and different componets of straw (cellulose, hemicellulose, lignin). In the first group experiment, the co-digestion of mixed sludge (MS) with corn straw (CS) and wheat stalk (WS) was compared with the mono-digestion of single substrate. The total methane volume released from group MS+WS and MS+CS reached to 187.01, 157.33 mL/g VSadded respectively, which means the increase of the methane yield by 1.52 and 1.28 times in comparison to group MS. Meanwhile the co-digestion system both have the synergistic effect on methane yield, the measured methane yield of group MS+WS and MS+CS enhanced 9.46% and 1.48% respectively when compared to the simulated methane yield.The pH level of co-digestion group MS+WS and MS+CS were maintained at a stable values from 6.48 to 6.90, it proved that the addition of mixed sludge can significantly increase the buffering capacity of the anaerobic digestion system. Moreover, the modified Gompertz model and first-order kinetic model was introduced to evaluate the kinetic parameters. The estimated parameters indicated that the co-digestion significantly increasing the max methane production rate and shortened the period of methane production. According to our second group experiment results, hemicellulose was hydrolysed and acidified more quickly than cellulose,while with the pH adjustment, it possess high biomethane potential than cellulose.The system of cellulose digested alone has better self-regulation., and cellulose co-digestion with sludge had a better methane production performance than the hemicellulose co-digestion with sludge. Addition of lignin had severe inhibition on the methane production of mono- and co-digestion, indicating that lignin should be pretreated or removed before entering the anaerobic digestion system. Therefore, the cellulose-rich straw is the best co-substrates for co-digestion with sludge.