| With the development of social economy, municipal sludge production is also increasing,and the treatment and disposal of municipal sludge should not be ignored. The comprehensive treatment of urban domestic refuses by principles of "no harm, decrement and reclamation" has been the main trend. Bioleaching technology is a new type of sludge dewatering technology developed in recent years,and the technology can realize the deep dewatering of sludge(moisture content below 60%), remediating heavy metals, killing pathogen, and preserving the beneficial ingredients in sludge to make better use of resources of sludge. This topic process parameter optimization of bioleaching technology for sludge treatment in the PTA and urban sewage sludge treatment through the shake flask experiments, small scale experiments, pilot experiments and production test, in order to achieve stable operation of bioleaching works or to reduce production costs.This paper was divided into two parts:the first part focused on Mitsubishi Chemical Co., Ltd. Ningbo PTA sludge bioleaching project,the research was to optimize the amount of bacteria in bioleaching process, optimize the amount of nutrients for germiculture, enhanced dewatering of PTA sludge with physical and chemical methods and optimize the dosing manner of microbial strains. The second part,the bioleaching projects in Wuxi Tai Hu Xincheng Wastewater treatment plants and Lu Cun sewage treatment plants for the study.The contents was to test the conventional dewatering sludge by bioleaching method, compare the effect of three generations microbial nutrients, and take physico-chemical methods to strengthen dehydration of the primary sedimentation sludge with high concentrations.The results were as follows:(1) The dehydration performance of PTA sludge after bioleaching treatment has been greatly improved. By further improving the production process,bioleached the PTA sludge by 6:3:1 mode, reducing the nutrient dosage by half in culture, adding bacteria one time with the proportional 3:3:2:2:1:1, complex physical and chemical conditioning after bioleching,the production process can be achieved stable operation.(2) Bioleaching can significantly improve the dewatering performance of municipal sludge. Through bioleaching treatment,the sludge filter specific resistance can decrease from 1.46×1013 m/kg before treatment decreased to 0.42×1012 m/kg, reduced by 97%.After the bioleaching of routine dewatered sludge, the effect was equal to concentrated sludge, and the moisture content of the filter press cake after membrane chamber filter press can be reduced to below 60%and the filtrate is colorless and odorless.It can reach the requirements.of the production.(3) Considerating the production efficiency, the second generation nutritional supplement is superior than the first generation nutrient,and it can replace the first generation nutrient into production. As the third generation nutrient has some problems to be solved, and the effect of bioleaching cannot reach the desired level, it will not consider large-scale use of the third generation.(4) We Determined the plan of dealing primary sedimentation sludge by the shake flask experiments, pilot test and production test:primary sedimentation sludge and bioleached sludge and second-generation nutritional supplement and liquid activator, the bioleached sludge is 20% of primary sedimentation sludge, the second-generation of nutrients is 7% of primary sedimentation sludge of the dry matrix,and the liquid activator is 14% of primary sedimentation sludge of the dry matrix. In this scheme, the amount of physical conditioning agents has been increased significantly than conventional bioleaching process, therefore the cost increase by 20% at the same time.It is not recommended when the bioleaching system is normal. |
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