为获得耐低温且絮凝优异的絮凝菌,对一株分离得到的絮凝菌进行紫外诱变和5℃低温胁迫培养,并对诱变优势菌进行应用条件优化.结果表明:(1)原始菌为蜡状芽孢杆菌(Bacillus cereus).(2)紫外诱变和低温胁迫培养得到的目标诱变菌FB-5对生活...为获得耐低温且絮凝优异的絮凝菌,对一株分离得到的絮凝菌进行紫外诱变和5℃低温胁迫培养,并对诱变优势菌进行应用条件优化.结果表明:(1)原始菌为蜡状芽孢杆菌(Bacillus cereus).(2)紫外诱变和低温胁迫培养得到的目标诱变菌FB-5对生活污水絮凝率达75.35%,具有良好的遗传稳定性.(3)单因素试验确定最佳絮凝条件,即絮凝菌投加量为0.90 m L/(50 m L)、p H为7.4、助凝剂加量为1.0 m L/(50 m L)、处理时间为15 min;筛选出影响诱变菌絮凝能力最显著的3个因素为絮凝菌投加量、p H和助凝剂加量;通过Box-Behnken响应面试验得到最佳净化的应用条件,即絮凝菌投加量为0.90 m L/(50 m L)、p H为7.38、助凝剂加量为1.04 m L/(50 m L).(4)验证试验确定絮凝率达97.01%,BOD5、CODCr、浊度和色度去除率均达到97%以上,出水水质满足GB 18918—2002《城镇污水处理厂污染物排放标准》一级A标准.研究显示,紫外诱变联合低温胁迫技术以及单因素与响应面结合优化絮凝条件可以大幅度提高原始菌株的絮凝能力,低温诱变菌FM-5能使高寒地区城市生活污水中悬浮固体大幅降低,同时去除水体中多种污染物.展开更多
The metallurgical sewage has very complex component and a significant environmental perniciousness and needs high treatment costs. In addition, too much low-temperature waste heat is emitted owing to the lack of suita...The metallurgical sewage has very complex component and a significant environmental perniciousness and needs high treatment costs. In addition, too much low-temperature waste heat is emitted owing to the lack of suitable users. Considering these concerns, a low-temperature-driven pretreatment method via vacuum distillation was proposed to treat the sewage from the metallurgical production. It uses the sensible heat carried by low-temperature exhausted gases to drive the distillation of sewage. The distilled water can be reused into the process as new water supply, while the enriched wastewater is discharged into the sewage treatment center for subsequent treatment. Converter dust removal sewage was chosen to perform an experimental observation. The variations of chemical oxygen demand, ammonia nitrogen, suspended solids, electrical conductivity, and pH of the condensate under different vacuum degrees and evaporation rates were mainly investigated. It can be found that the quality of the condensate gets better under certain conditions, which validates the feasibility of the proposed approach. Furthermore, by comprehensively analyzing the water quality indices and their influencing factors, the optimal vacuum degree was suggested to be controlled between 0.07 and 0.09 MPa, and the best evaporation rate was between 40 and 60%.展开更多
文摘为获得耐低温且絮凝优异的絮凝菌,对一株分离得到的絮凝菌进行紫外诱变和5℃低温胁迫培养,并对诱变优势菌进行应用条件优化.结果表明:(1)原始菌为蜡状芽孢杆菌(Bacillus cereus).(2)紫外诱变和低温胁迫培养得到的目标诱变菌FB-5对生活污水絮凝率达75.35%,具有良好的遗传稳定性.(3)单因素试验确定最佳絮凝条件,即絮凝菌投加量为0.90 m L/(50 m L)、p H为7.4、助凝剂加量为1.0 m L/(50 m L)、处理时间为15 min;筛选出影响诱变菌絮凝能力最显著的3个因素为絮凝菌投加量、p H和助凝剂加量;通过Box-Behnken响应面试验得到最佳净化的应用条件,即絮凝菌投加量为0.90 m L/(50 m L)、p H为7.38、助凝剂加量为1.04 m L/(50 m L).(4)验证试验确定絮凝率达97.01%,BOD5、CODCr、浊度和色度去除率均达到97%以上,出水水质满足GB 18918—2002《城镇污水处理厂污染物排放标准》一级A标准.研究显示,紫外诱变联合低温胁迫技术以及单因素与响应面结合优化絮凝条件可以大幅度提高原始菌株的絮凝能力,低温诱变菌FM-5能使高寒地区城市生活污水中悬浮固体大幅降低,同时去除水体中多种污染物.
基金This work was sponsored by the National Natural Science Foundation of China （51734004, 21561122001）, the China Scholarship Council （201702660037） and the Fundamental Research Funds for the China Central Universities （N162504011）.
文摘The metallurgical sewage has very complex component and a significant environmental perniciousness and needs high treatment costs. In addition, too much low-temperature waste heat is emitted owing to the lack of suitable users. Considering these concerns, a low-temperature-driven pretreatment method via vacuum distillation was proposed to treat the sewage from the metallurgical production. It uses the sensible heat carried by low-temperature exhausted gases to drive the distillation of sewage. The distilled water can be reused into the process as new water supply, while the enriched wastewater is discharged into the sewage treatment center for subsequent treatment. Converter dust removal sewage was chosen to perform an experimental observation. The variations of chemical oxygen demand, ammonia nitrogen, suspended solids, electrical conductivity, and pH of the condensate under different vacuum degrees and evaporation rates were mainly investigated. It can be found that the quality of the condensate gets better under certain conditions, which validates the feasibility of the proposed approach. Furthermore, by comprehensively analyzing the water quality indices and their influencing factors, the optimal vacuum degree was suggested to be controlled between 0.07 and 0.09 MPa, and the best evaporation rate was between 40 and 60%.
