Research On Biological Treatment Of 2,4-dichloro-3,5-dimethyl-phenol In High Salinity Wastewater

The sources and composition of wastewater containing chlorophenol are very complex.These kinds of wastewater mostly contains not only high concentrations of phenolic compounds,but also a lot of salinity.High salinity industrial wastewater containing chlorophenol is very difficult to be treated.The purpose of this study is screen a strain from the wash protect agent production wastewater,which has the capacity of high salt-tolerant and chlorophenol degradation.With an initial observation and analysis of colony morphology,electron microscope and 18S rDNA molecular biotechnology identification,the screened strain was identified as penicillium,named YZ-11.This experiment studied the degradation ability of the screened strain under different conditions in simulate wastewater containing 2,4-dichloro-3,5-dimethyl-phenol(DCMX).In addition,the research about the effect of DCMX on screened strain during degradation process was also studied.The growth curve and the growth characteristic of the strain YZ-11 under different pH value were studied,moreover the influence of carbon source on YZ-11 growth has also been studied.YZ-11 grew fast when cultivated in of the shaking incubator with condition of 140 r/min,temperature 30°C,and avoiding light,found that,under this condition,growth of strain entered rapid growth period after about 20h.Under the condition of weak acid,pH was about 6.0,the growth rate of YZ-11 was highest.The effects of different pH,substrate concentration,temperature and salinity conditions on the DCMX degradation characteristics of YZ-11 were studied.Results showed that optimum DCMX degradation pH of strain was around 6.0,the degradation rate firstly increased with increasing pH,and then decreased with continuous increasing pH.The DCMX removal rate gradually decreased along with its continuous improvement concentration.Similarly,DCMX degradation rate decreased with the increasing salinity.The analysis of the infrared spectral changes fully proved that the DCMX degradation ability of the screened strain.Through the orthogonal experiment,we found that decisive significant factors effect on DCMX removal was salinity,temperature,and then pH.Under the optimal conditions,2.6%salinity,pH value of 5.87,and temperature of 32.06?,DCMX removal rate was 98.38%.In addition,the study found that the DCMX toxicity could affect the growth of strain YZ-11,change the composition of membrane material,and destroy the stability of cell membrane.DCMX can affect the microbial enzyme activity to a certain extent.As the extension of incubation time,the Extracellular Polymeric Substances(EPS)of YZ-11 has obvious changes,EPS firstly increased,and latter decreased.In this study,we isolated identified a strain for the first time,which has high efficient degradation DCMX salt-tolerant capacity.By using the microbial technology,the inhibition of traditional biological treatment process of high salinity wastewater containing chlorophenol could be improved very well.