Microbial Analysis And Application Of Bio-enhanced Treatment Technology Of Chemical Bamboo Pulp Wastewater

China's Sichuan Province is rich in bamboo resources.With the promulgation and implementation of the national waste prohibition order,there is great potential for popularization of bamboo-based pulping and papermaking,which ishelpful to solve the problem of shortage of raw materials.In the process of bamboo pulping and papermaking,a large amount of wastewater is produced ofhigh concentration andhigh chroma.If these wastewater could nothandled properly,it will cause serious environmental problems.Therefore,it is an urgent problem to construct an efficient,stable and sustainable bamboo pulp wastewater treatment system.At present,the research focus is on reducing the load of advanced treatment by improving the efficiency of secondary biochemical treatment,thereby reducing the chemicals and the operating costs of enterprises.According to the pollutant characteristics of chemical bamboo pulp wastewater,this work analyzed the microbial community structure in the activated sludge of an actual chemical bamboo pulp wastewater treatment plant,and strengthened the aerobic treatment system with commercial microbial agents to improve the treatment efficiency of aerobic units and reduced the pollution load of advanced treatment.In this work,the comprehensive influent and activated sludge of four chemical bamboo pulp pulping and papermaking enterprises in Sichuan Province were taken as the research objects.The water quality characteristics of chemical bamboo pulp wastewater were investigated by GC-MS and ICP-AES.The research showed that the dissolved organic matter in chemical bamboo pulp wastewater before biological treatment washigh,and its CODCr and BOD5 were 788mg/L and 326mg/L,respectively,and BOD5/CODCr was 0.41,so the biodegradability of the wastewater was in general level.According to the biodegradation rate,the types of organic matter were classified.The proportion of the easily biodegradable chemicals in the chemical bamboo pulp wastewater was 23.10%,the organic carbon was mostly slow biodegradable organic matter,accounting for 61.19%,and the rest was inert organic matter.This meant that the slow biodegradable organic matter accounts for a veryhigh proportion,so it is possible to try to adopt the bioaugmentation technology to further improve thtreatment efficiency.There are a lot of chromatizing and chromatizing groups in the chemical bamboo pulp wastewater,which makes the chromaticity of the wastewater darker.The organic pollutants in the wastewater were obtained by GS-MS analysis,including benzoic acids,alkanes,alcohols and lipids.After biochemical treatment,the CODCr and BOD5 of the chemical bamboo pulp wastewater decreased significantly to 206mg/L and 7mg/L,respectively,and the removal rates reached 73.85%and 97.85%.After biochemical treatment,the number of detected substances decreased by 11,and the peak area and intensity of the characteristic pollutants decreased obviously,indicating that the biochemical treatment effect was remarkable.The differences of microbial population structure of activated sludge in different aerobic treatment units of chemical bamboo pulp wastewater were analyzed.It was mainly due to the differences of influent water quality and treatment technology,which led to their continuous evolution and formed the diversity and difference of colony structure.In the aerobic treatment unit of chemical bamboo pulp wastewater,the dominant bacteria include Proteobacteria,Chloroflexi,Bacteroidetes and Actinobacteria.The abundance of Proteobacteria is 35.76%?59.47%.The core genera are:Hygrophobium,SWB02,Bryobacter and Hyphomicrobium.Among them,Hyphomicrobium is dominant,and its abundance is 3.69%?18.29%.These bacteria are not only related to nitrification and denitrification,but also directly related to the degradation of polycyclic aromatic compounds,alcohols and alkanes.These results provided a theoretical reference for the dominant bacteria in aerobic treatment unit to be used as strengthening agents to construct artificial control flora for bamboo pulp wastewater with different characteristics.When the CODCr degrading agent was 30mg/L,PP 50mg/L,OBT cracking agent 30mg/L,aeration time 24h,reaction temperature 30?,initial pH 7,the CODCr removal rate was 62.45%,which was 22.30%higher than that of the control group.The analysis showed that the organic matter wouldhave relatively less conjugated structure after the bio-enhanced treatment of wastewater,and the wastewaterhad relatively lower absorbance in the visible range.The wastewater still containd benzene rings,phenols,lipids and other substances,but ithad relatively less content.It was speculated that microorganisms first consume fast biodegradable organic matter,and secrete lignin cellulase and laccase,etc.,and at the same time,they would break the bonds connecting lignin,and finally produce monomers,which can finally appear as low molecular weight compounds after decomposition.Quinones were mostly oxidized into aldehydes and ketones by laccase.Ketones can produce guaiacol which is ring-opened.The main products formed in this stage were aromatic ketones and lipids,which could be easily used by microorganisms,thus reducing the chromaticity of wastewater.These results provided a theoretical reference for the construction of enhanced microbial agents in aerobic treatment units to artificially control the flora of bamboo pulp wastewater with different characteristics.This work provides a theoretical basis for better solving the pollution problem of bamboo pulping and papermaking wastewater and the application of commercial bacteria agent in chemical bamboo pulp wastewater treatment.