The Research On The Anaerobic Digestion Of Leachate From Municipal Solid Waste Incinerator With The Pig Manure As Substrate Under The Mesophilic Condition

The experiment researched the leachate from the incinerator of the municipal solid waste with pig manure as a substrate under the mesophilic anaerobic digestion in two different reactors by two different feeding ways to find the optimal organic load rate.(1) The anaerobic digestion system with500mL pig manure as substrate by fed-batch feeding mode could operate with7volumetric loading rates (VLR, VLR of5%、10%、15%、20%、25%、30%、35%).At the VLR of5%,10%,15%, the digestion system ran well with3days of HRT in5times of feeding by each VLR. With the feeding leachate increased, gas production of the system gradually rose, the methane content was stable, and pH, VFA, alkalinity, ammonia of the system were good for anaerobic digestion.At the VLR of20%and25%, gas production and methane content was increased slowly, and the daily gas production of the system appeared two peak values which were1950mL and1980mL respectively. At the same time, with feeding more leachate into the system, the VFA concentration went up to a higher level, and that dropped down to a lower level after prolonging the period of HRT.At the VLR of30%, the system still could run normally, but VFA were overtop, gas production dropped sharply, and the ammonia of the system was accumulated to a certain extent. At the VLR of35%, the VFA of the system was accumulated to high level and the gas production was even less than that of the VLR of5%. That means that the VLR of35%was too high for the anaerobic digestion.The methane content maintained about40%-70%basically during the operation of the7VLRs, and the highest was75.5%. According to the study of the system with the7VLRs,20%and25%are better for the reactor by fed-batch feeding mode in which we can get qualitative gas production, but HRT should be controlled well.(2) The anaerobic digestion was conducted in the anaerobic CSTR reactor with6L pig manure as the substrate by semi-continuous feeding leachate mode.The anaerobic digestion system ran with5OLRs(0.7、1.4、2.1、2.8、3.5g/(L-d)):At the OLRs of0.7、1.4、2.1g/(L-d), the system was steady, daily gas production increased, methane content tended to be stable and the other indicators maintained normal level while raising the OLRs;At the OLR of2.8g/(L·d), the system turned to be unsteady, but the maximum daily gas production about12880mL was obtained with the methane content about59.8%during the period by extended feeding intervals;At the OLR of3.5g/(L·d), the system was unable to sustain steadily, methane content was also verged on0. That means that3.5g/(L·d) is the highest OLR.(3) By comparing the two reactors by two different feeding ways, the reactor with500mL pig manure as substrate by fed-batch feeding leachate mode could take a higher loading rate.