Experimental Study On The Adsorption Effect Of Compound Bacteria On Lead-containing Wastewater

With the rapid development of mining,electroplating,smelting and other industries,the pollution of heavy metal lead has occurred from time to time.Lead has the characteristics of refractory degradation,long-lasting toxicity,and easy accumulation,which seriously threatens the survival of organisms and human health.Therefore,strengthening lead pollution control technology research and finding cost-effective and environmentally friendly treatment methods are of great significance to improving the lead pollution environment.Traditional chemical methods,physical and chemical methods,etc.have many disadvantages in the treatment of lead-contaminated wastewater.Biological methods have the advantages of high efficiency and speed,no secondary pollution,wide sources of raw materials,and extremely low cost.It is to improve the ecological environment,One of the best choices to deal with the environmental pollution of heavy metals.This thesis builds a composite bacterial agent based on lead-resistant microorganisms,verifies the adsorption effect of the composite bacterial agent on lead-containing wastewater through simulation experiments,and analyzes the adsorption conditions and influencing factors,in order to provide certain technical support for the microbial remediation of lead-contaminated water.The main research conclusions obtained in the thesis are as follows:（1）The lead-tolerant bacteria in lead-containing soil were screened and identified,and 5 strains with significant lead adsorption were obtained.Orthogonal experiments were used to construct Bacillus subtilis and Enterobacter cloacae.,Pseudomonas aeruginosa and Enterobacter ludwigia are a composite inoculum composed of strains,and the mixture ratio of strains is 3:2:2.5:2.5.（2）The optimal conditions and influencing factors for the composite bacteria to adsorb lead are determined.Under the optimal conditions of pH=5.0,temperature of 35℃,reaction time of 6 h,and initial Pb²⁺ concentration of 100.0mg·L^-1,the lead adsorption rate can reach 99.48±0.03%.C/N,total phosphorus,total nitrogen,ammonia nitrogen and carbon source types have different effects on the lead adsorption efficiency of the composite bacteria:the increase of C/N and total phosphorus can significantly reduce the lead adsorption rate of the composite bacteria,and the total nitrogen affects the composite bacteria The lead adsorption rate of the compound microbes has little effect.The increase of ammonia nitrogen increases the lead adsorption rate of the composite microbial agents.The type of carbon source has a significant difference in the effect of the lead adsorption rate of the composite microbial agents.In addition,the compound bacterial agent has certain removal ability to total phosphorus,total nitrogen and ammonia nitrogen.（3）The treatment effect of the compound microbial agent in the simulated industrial lead-contaminated wastewater was verified.Under the simulated low lead pollution(Pb²⁺=4.1mg·L^-1)level and medium lead pollution(Pb²⁺=56.7mg·L^-1)level,the lead adsorption rate of the composite microbial agent was both greater than 90%,while at the high lead pollution level Under the pollution(Pb²⁺=169.2 mg·L^-1)level,the adsorption rate of the composite bacterial agent decreased slightly,but it still maintained more than 80% of the highest adsorption rate.