Optimization Research On City Sewage Plant Sludge And Eat Hutch Garbage Two-stage Anaerobic Process

Sewage sludge and food waste are high-value solid waste recycling, anaerobicdigestion of a mixture of both can improve system stability, enhance the removal oforganic components of the substrate, enhancing food waste anaerobic digestion industrialfeasibility of biogas production. Treatment and disposal methods for sewage sludge andfood waste, combined with the characteristics of the two municipal waste by anaerobicfermentation theory, proposed two-phase anaerobic digestion of food waste and sludgewere fermented to make full use of sludge food waste in the microbial activity and theorganic matrix, the fermentation can achieve high speed and efficiency. By study andcompare the material removal rate and COD concentration, the percentage of daily gasproduction and the methane ratio and determine the best dosage rate. The results showedthat:For primary fermentation discharging, entered the secondary fermentation tank afternitrogen treatment, so as to remove high ammonia nitrogen concentration on inhibition offermentation reaction, thus the secondary fermentation tank, the lower initial concentrationof ammonia nitrogen were, then ammonia nitrogen concentration increased, this may bedue to the rise of PH in the secondary fermentation tank and some caused by microbialdigestion reaction.Mix ratio of3:1, under the condition of different rate,COD, VFA, VS in the reactionachieve stable in about50days, therefore the time needed for this experiment, the batchingrate had little impact on the time needed to reach stable reaction.In the3:1ratio of sludge mixed with food waste,12%of the dosing rate under theseconditions was the best on the concentration of COD this case was13500mg/L, VSremoval rate was44.1%;the daily methane capacity was10978mL; mixing ratio of4:1,with a ratio of16%of the vote in this condition was the best, the COD concentration at thistime was7494mg/L, VS removal rate was50.23%,the daily methane capacity was7975mL; mixing ratio of5:1, the dosage rate of16%under the best conditions, theconcentration of COD in this case was13761mg/L, VS removal45.13%, the dailymethane capacity was5720mL.The time required to reach steady from PH, ammonia, COD, VS and other indicatorscan be seen, the mixing rate of different level to some extent influence the time needed to stabilize the static fermentation,it also had influence on the secondary reaction.The highermixing rate of sewage sludge and food waste,a relatively higher content of microorganisms,the less content of organic matter, and the shorter time it required for stability.In the secondary fermentation under the condition of batching rate of12%,differentmixing ratio on the reaction tanks had a certain influence on SCOD concentration, VSconcentration and its removal rate, the daily gas volume, the percentage of methanecontent in the gas, such as mixing ratio of3:1,4:1,5:1, SCOD concentration stabled13500mg/L,10000mg/L,23000mg/L respectively, the mixing ratio of4:1, dischargeSCOD lowest concentration. VS content increased with the increase of mixing ratioincreases, were0.0347(g/g materials),,0.0396(g/g materials) and0.0456(g/g materials)respectively, and its removal rate were42.8%,26.7%,5.2%respectively; Each reactiontank’s gas volume decreased with the increase of mixing ratio, reaches12000ml/d,5500ml/d,4500ml/d,respectively, the percentage of the methane production reaches92.49%,91.55%,88.69%respectively.In summary, when the food waste and sludge mixing ratio was3:1, the dosing ratiowas12%, the density of the material’s COD was13500mg/L, the removal rate of CODwas87.5%, the removal rate of VS was44.1%, on the amount of methane was10978mL,under this condition, the lower the concentration of the material COD, a higher removalrate of COD and VS.the highest per day production of methane, the higher efficiency ofthe anaerobic digestion reactor, in practice also feasible.