Research On The Effect And Influence Mechanism Of PTA Sludge Biological Drying

In recent years,the production of chemical sludge was increasing.Chemical sludge is mostly hazardous waste,with high toxic substance content,and mostly incineration disposal,but the cost was very high.Therefore,it is urgent to reduce the amount of hazardous waste sludge.Biodrying technology is a green,economic and feasible method for the treatment of hazardous waste sludge in chemical sewage plant.In this paper,the optimal conditions and continuous reaction effects of biological drying of PTA wastewater sludge from a chemical fiber plant were explored,the mechanism of sludge biological drying was revealed,a pilot plant with a treatment capacity of 3t / d was designed and evaluated.This paper completed the following parts:(1)The results show that the optimal conditions of sludge biodrying are one-time feed,60 ? equipment temperature and 4% microbial agent.Under the optimal parameters,the continuous reaction effect of the small-scale test equipment is stable,the moisture content is reduced to below 20% after 24 hours,the moisture content is reduced by 79.4%,the dry matter is reduced by 22%,and the toxic substance is reduced by 9%.(2)In the process of biodrying,the change rule of material characteristics showed that the period of biological drying is short,the sludge will not be completely decomposed,but a large amount of carbon and nitrogen sources will be consumed to supplement the nutrients needed for microbial degradation.The analysis of the spectral characteristics of DOM showed that the macromolecular substances were degraded along with the reaction,humic substances were gradually synthesized,the degree of DOM aromatization in the effluent sludge increased,the incineration value was high,and the risk of environmental pollution was low.(3)The influence mechanism of sludge biological drying was explored.Firstly,high-throughput sequencing was used to study the change of microbial community structure and draw a dynamic succession model.It was found that species richness and diversity decreased in high temperature stage.The main metabolic pathways of bacterial community were amino acid metabolism,carbon hydrate metabolism and general function prediction.Secondly,correlation analysis,principal component analysis and PLS regression analysis were used to determine the key influencing factors of the reduction effect.It was found that the key influencing factors of water reduction were Gemmatimonas,Novosphingobium and Azohydromonas,of dry matter reduction were Pelotomaculum,Tom,DOC and C / N ratio,of toxic substances reduction were brevundimens,novosphingobium and Gemmatimonas.(4)The analysis of the operation effect of the biodrying pilot test equipment showed that the pilot test temperature was lower than 80 ?,the sludge moisture content was 85% and the sludge reduction rate was over 75% after 28 h drying treatment,the continuous operation effect was stable;the tail gas and condensate were discharged up to the standard,the reduction and harmless treatment of hazardous waste sludge were realized,and the cost of incineration and landfill was about 6000 Yuan per ton,both environmental and economic benefits were significant,which provided technical support for the application and demonstration of key technologies of hazardous waste sludge reduction in a chemical fiber plant.