| With our country’s emphasis on environmental protection, the number of city sewage trea tment plant is also increasing, resulting in thewaste water is also more and more. Due to th e strict environmental protection legislation and the awareness of environmental protection, h ow to dispose of surplus sludge called people focus. Biological hydrogen production by organ ic matter in sludge, hydrogenenergy is clean of the double meaning of excess sludge reductio n and resource processing and obtain.In order to realize the sludge reduction, resource utilization, reduce the pollution of the environment. The study on excess sludge first freeze-thaw pretreatment and biochemical meth ane potential experiments(BMP) to determine the optimum pretreatment conditions. Then t he freezing thawing sludge after pretreatment of the matrix, Excess sludge of anaerobic ferme ntative hydrogen productionexperiments, effects of freezing and thawing after pretreatment o f sludgeanaerobic fermentation of biodegradable, and observed the changes of gas hydrogen production.The results showed that:(1) Under the same temperature, with the freezing time prolonge d, the excess sludge is almost constant in the TCOD values before and after freezing and t hawing, SCOD values increased. Excess sludge through the freeze-thaw pretreatment, p H valu e decreased, and the basicity is increased, the content of NH3-N. The growth of TS and V S value of the sludge is consistent with TCOD, not with the freezing temperature,freezing ti me change. Frozen sludge SS and VSS values increased withdecreasing state freezing time.(2) Experimental results show that under the condition of the temperature of-18℃, freeze/thawing of 72h/3h,SCOD of the sludge increased, SS decreased and VSS values were better than those of the other temperature conditions. From(1) to know the same temperature, free zing timeis longer, the sludge can be dissolved. Comprehensive analysis: the sludge under th e condition of the temperature of-18℃, freeze/thawing of 72h/3h thebest of SCOD and V S solubility.(3) After the BMP start of the experiment, the sludge by freezing in the 19 d to generate the first small peakperiod, the original sludge appeared peak of gas production in the 29 d. In the experiment of BMP within 23 d of the onset of freezing thawing, the remaining differenc e before and after pretreatment of sludge properties. With the continued operation of the system and tends to be stable after freezing and thawing, the sludge after pretreatment of the cu mulative biogas yield was 1200 m L, increased by 33% than the original sludge.(4) Ethanol fermentation bacteria cultivation and domestication stage nutrition and hydraulic conditions, COD:N:P=200:5:1;HRT is 8h, temperature is(35±1)℃, influent COD concentratio n increased from 3000 mg/L to 5000mg/L, 100 d to complete the operation of reactor of etha nol type fermentation bacteriaculture.(5) In the reactor was stable after the operation, the influent organic load is 25.3kg COD/ m3?d, the SCOD removal rate remained at around 25.7%; the concentration of VFA reach ed 3430mg/L in the system is stable; the influent p H value is 7.55~9.30, the effluent p H valu e in the range of 4.15~4.25, suitable for ethanol type fermentation, this time the average hyd rogen production reactor volume was17.6L/d, the total average hydrogen gas content is 31.8%.(6)Two groups of system in the start-up period of sludge into sludge quantity is 2.0L/d, th e p H value is about 4.2,temperature is(35±1)℃, freeze/thaw group and the original sludge re actor respectively to the 17 d and the 20 d started successfully.(7)When the organic load of 6.98 kg VS/m3?d, 10.35 kg VS/ m3?d,13.97 kg VS/ m3?d, freeze-t haw pretreatment group TS removal rate than the original sludge was improved by 27.1%, 12.5% and 0.03%;freeze-thaw pretreatment group compared with the original mud removal rat e of VS were increased by 11.2%, 24.2% and 7.3%; freezing and thawing group, the remov al rate of SS is lower than that of the Ni group increased 6.1%, 17% and 11.3% respectivel y; the removal rate of VSS is lower than that of the Ni group increased 7.5%, 27.27% an d 22.7%.(8) The control group sludge group and freeze/thaw group total biogas sludge and hydrogen production at different organic loading had a certain degree of increase in organic load is 6.98 kg VS/m3?d, 10.35 kg VS/m3?d and13.97 kg VS/m3?d, total gas production of raw sludge sludg e were 1088 m L/d, 2100 m L/d and 2850 m L/d, freeze / thawing group total biogas production of sludge were 1930 m L/d, 3250 m L/d and 3930 m L/d. |
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