| With the development of social economy and urbanization of our country, the production and quantity of the municipal sewage are increasing constantly. At the same time, because of the waste water processing technology further promotion as well as the standard strictly day by day, the sludge output is bigger and bigger. Casual disposing the untreated sludge will cause the serious pollution. So it becomes a more attention-getting discussion in the world's environmental circles that how to make the volume-vast and composition-complicated sludge inoffensive and energy-producing by scientific process.According to the characteristics of the sludge of Xi'an city's wastewater treatment plant, the paper adopts mesophilic two-phase anaerobic digestion to treat sludge, and compares its results with the mesophilic signal-phase anaerobic digestion data, then makes a theoretical analysis.Some conclusions inferred from the mesophilic two-phase anaerobic digestion are: sludge can run steadily when HRT is 13.75 days and organic load is 4.68 kgVS/m3·d, VS reduction is 73.7%, COD reduction is 76.83%, and pH is about 7.4.Through the experiment, the two-phase anaerobic digestion is suit for discharging the excess sludge from wastewater treatment plant. This craft system can improve the production, after optimized processing, it can enhance the sludge stability and achieve this function-reducing the quantity and volume. When the organic load is low, the system moves stably and the processing effect is good, simultaneously increasing the organic load leads to a good sludge character.After making a heat energy analysis, we found that not only in common days but also the extremely coldest winter days, the two-phase system could produce enough heat to satisfy the system, without heat supplement.Based on the experiment, we educe the kinetics model to analyze two-phase anaerobic digestion system and gain the parameters of methane-phase: K= 0.0162 L· g-1·d-1; Sn= 13.537 g/L; Y=7.3153gVSS/gCOD; Kd=0.5589d-1'.
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