| With the development of economy,there was a rapid increase in the yield of sewage and sludge.If a large amount of sludge was not disposed reasonably,it would cause pollution to our environment.Sludge composting was an effective way to met the sustainable development strategy.However,the sludge composting technology was a complex reaction system which was greatly influenced by the operational factors like additives,in order to improve the effect of sludge composting,it is necessary to optimize the process of sludge composting.In this study,the effects of additives on sludge compost were studied to optimize the composting process parameters and improve the composting effect.In order to research the mechanism of composting,the three kinds of sludge(Datansha municipal sludge,Lijiao municipal sludge and printing and dyeing sludge),sawdust and mushroom residue were used for aerobic composting at the ratio of 10:3:1 seperately,all of they could meet the requirements of the composting harmlessness,and the product from municipal sludge had a stimulative effect on plant growth;by means of high throughput sequencing technology,it was found that in same process of different piles,the change rule of bacterial community was similar,but for the same pile at different process,the similarity of dominant bacteria was low.As to further improve the effect of composting,sludge-straw based biochar was prepared from the municipal sludge and straw,and its properties were analyzed by X-Ray Diffraction(XRD),Scanning Electron Microscope(SEM),Brunner-Emmet-Teller(BET)and Fourier Transform Infrared Spectroscopy(FTIR).Then,municipal sludge,sawdust and mushroom residue were used as materials for composting,and the effect of the pile added with/without sludge-straw based biochar was compared by determining temperature,organic matter,pH value and germination index(GI).The results showed that:(1)sludge-straw based biochar had pore structure and hydrophilic functional group,which was beneficial to composting;(2)There were better performance in temperature,organic matter,pH value and GI of the pile added with sludge-straw based biochar.All in all,sludge-straw based biochar could accelerate the reduction and harmlessness of the dewatered sludge,which is favorable to the sludge composting.In order to achieving the deep detoxification of sludge,the municipal sludge,sawdust and mushroom residues were chosen as raw materials of composting,the effect of the pile added with/without the soil from Guiyu was compared by determining temperature,pH value,organic matter,moisture content and GI.the effect of adding soil from Guiyu to the pile onthe removal of decabromodiphenyl ether(BDE209)was also evaluated.In addition,the relevant microbial degradation system of BDE209 was prepared through the enrichment culture of microorganisms in the pile to test whether the microorganisms played an important role in the removal of BDE209.The results showed that the durations of two piles at the temperature above 55? were 7 d and 6 d respectively,which have met the requirement of maturity.The addition of soil from Guiyu to the pile had positive impact on the removal of BDE209 and GI.After addition of soil from Guiyu to the pile,the GI increased from 85.2% to102.3%,the BDE209 concentration decreased from 86.2% to 28.2%,The degradation rate of BDE209 by the microorganism from the compost added with soil was 53.0%,but as for another one without addition of soil,the degradation rate of BDE209 was only 8.6%,the results showed that biodegradation was the main removal pathway of BDE209 during sludge composting. |
PDF Full Text Request