| With the rapid development of my country’s industry,the amount of industrial wastewater discharge has increased year by year,and reportedly reached 20 billion tons in 2018.Due to its own characteristics,industrial wastewater contains a variety of compounds,such as drugs,organics,heavy metals,personal care products and other emerging pollutants,which may have potential adverse effects on the water environment or humans.However,due to the lack of standardized management based on toxicity evaluation indicators for wastewater discharge,we know little about the toxicity and possible effects of wastewater.A large amount of industrial wastewater is concentrated in wastewater treatment plants.Therefore,in recent years,the water quality toxicity and toxic degradation and changes in each treatment stage in the centralized treatment of wastewater treatment plants have aroused widespread public concern.In this study,the whole-cell yeast cell microarray detection technology based on toxicological genomics was used to evaluate the toxicity status of the influent water from an industrial wastewater treatment plant and the water quality of the influent water samples(including the toxicity of organic components in the water samples,Toxicity of heavy metal components and non-volatile components(ie comprehensive toxicity),this method can obtain more detailed protein expression effect levels of selected functional genes under the detection target exposure,and can more accurately understand the toxicity mechanism and toxicity of the test sample.In addition,this toxicity evaluation method can also use the degree of change in the stress response of the functional genes of the cell and use the protein expression effect level index(PELI value)to quantitatively describe the toxicity level of the test sample,which is helpful for us to understand the industrial wastewater in the wastewater.It is of great guiding significance to deal with the toxicity changes under the treatment process of the plant manager.This research further analyzes the conventional parameters of water quality,water quality fingerprints(such as organic carbon and organic nitrogen molecular weight distribution,fluorescent component substances),the conventional parameters of activated sludge of the biological treatment unit,and the activity of biological enzymes,and activities of the various treatment stages of wastewater treatment plants.The organic component content of microbial metabolites and extracellular polymers in the sludge samples,organic carbon,organic nitrogen molecular weight distribution characteristics,and fluorescent component characteristics were measured.At the same time,the water samples and activated sludge were measured.The abundance of antibiotic resistance genes(ARGs),and the use of high-throughput sequencing methods to comprehensively evaluate the composition and abundance of microbial populations in water and mud samples.A comprehensive analysis of the above results found that after the various processing units,many pollutants such as chemical oxygen demand(COD),total nitrogen(TN),ammonia nitrogen(NH3-N),total phosphorus(TP)and organic components were heavily polluted.Removal,the effluent reaches the first-level A standard,and the growth state and biodegradability of activated sludge are verified at the same time.After comprehensive analysis,the main pollution of this industrial wastewater plant is organic pollutants and nitrogen pollution.However,the toxicity test results show that under the condition that the water quality,sludge and other parameters are all up to the standard,the water toxicity is not well degraded.In addition,the toxicity of the water quality increased significantly after the biological treatment unit and the ozone catalytic unit,and the effluent toxicity of the secondary sedimentation tank also showed a slight increase.Redundant analysis and Spearman are used to analyze the correlation between other indicators and the comprehensive toxicity of water quality.The results show that water quality toxicity is related to carbon,nitrogen,phosphorus,various organic components,heavy metal components,ARGs and microorganisms.There is a certain correlation among multiple indicators such as community structure.The above results may help to understand the current status of the toxicity of industrial wastewater and the removal effect of the treatment technology currently used in China.The conclusions obtained can be summarized as the following conclusions:1.The test results of various conventional water quality parameters show that this industrial wastewater treatment plant can effectively treat incoming industrial wastewater and achieve first-level discharge under normal operating conditions.2.The conventional parameters of activated sludge and the main biological enzyme data show that the activated sludge of the biological treatment unit in this wastewater treatment system has a good growth state and good biodegradability.3.The toxicity results of the water quality obtained through the yeast whole cell array show that even after the industrial wastewater treatment plant effectively removes COD,TN,TP and other pollutants,the water quality after the influent is treated by the anaerobic/aerobic biological treatment unit There is still a significant increase in toxicity,and the results are consistent regardless of whether it is high temperature or low temperature conditions.It is speculated that this may be caused by the complexity of microbial treatment.4.In addition,the toxicity results also show that the water quality toxicity will also increase significantly after the influent water passes through the secondary settling tank treatment unit,and the temperature effect is not obvious.It is speculated that this may be caused by the release of pollutants from the activated sludge.5.The ozone-catalyzed advanced oxidation treatment unit will increase the toxicity of water quality,which may be caused by the production of more toxic oxidation by-products.6.Redundancy analysis and Spearman correlation analysis show that multiple pollution indicators such as conventional water quality indicators,organic components,heavy metal components,ARGs,etc.all have a certain correlation with water toxicity,and have some impact on water toxicity.And these indicators will further affect the toxicity of water quality by affecting the microbiome structure. |
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