Potential Biological Safety Risk In Antibiotic Wastewater Treatment Process

At present, antibiotic-resistant-bacteria become more and more serious in clinic, which menace human health. Domesticating bacteria with abilities of antibiotic resistance and degrading antibiotic and organic compound in wastewater is the key of antibiotic wastewater biological treatment process. It is reasonable for wastewater treatment, but it might contribute to spread antibiotic-resistant-bacteria in environment.In this study, the antibiotic susceptibility changing phenomena and mechanism of sludge microorganism isolated before and after domestication have been investigated, it is indicated that bacteria resistant exist in antibiotic wastewater treatment process undoubtedly. Then the necessary forward or backward treatment forms were suggested. The Sequencing Batch Reactor Activated Sludge Process (SBR) reactor was constructed to simulate antibiotic treatment process; the bacteria were isolated from reactor before and after domestication, and the Minimal Inhibitory Concentration (MIC) values were measured. The antibiotic resistance naturally retrogressive was explored, and the gene mutation mechanism of resistant-bacteria was indicated by Denaturing Gradient Gel Electrophoresis (DGGE). The research results are as follow:(1) The concentrate of sensitive bacteria has increased after antibiotic wastewater domestication process. The insensitive percent increased from 55.7 to 70.5.(2) Enzyme regulation mechanism leads to increase the MIC values of 59% sludge microorganism. Sludge microorganism resistance which based on this mechanism can be eliminated naturally, it is non-genetic resistance.(3) Gene mutation or gene acquirement can also lead to insensitive bacteria; it is genetic resistance. There is biological problem in the effluent and sludge which based on this mechanism; it will be secondary pollution if let sludge microorganism into environment without treatment.(4) There was biological risk in antibiotic wastewater treatment process, In order to solve this problem; a method is adding pre-treatment or post-treatment in treatment process. The pre-treatment includes changing antibiotic molecular structure and degrading antibiotic by physical-chemistry methods. The aim of post-treatment was to kill resistant bacteria before leting into environment.