Study On Process Of Treatment Of Printing And Dyeing Wastewater By Complete Biological Methods And Engineering Practice

In this study, CODcr, pH and chroma were investigated in the treatment process of printing and dyeing wastewater. The index of major pollutants was accorded with the requirement of first grade of Water Pollutant Discharge Extreme. SEM was used to scan the morphology of sludge,because it was composed of a variety of rod-shaped bacteria and spherical bacteria attaching to EPS, the sludge was able to form better sludge floe and had better flocculation.It was suitable for treating printing and dyeing wastewater.The extraction of EPS from activated sludge in different phases were studied under three conditions,such as formaldehyde-NaOH,H2SO4and glutaraldehyde methods.lt was concluded that formaldehyde-NaOH treatment was more effective than the glutaraldehyde method.Then it was studied that the impact on EPS flocculation by changing the pH value and the concentration of EPS and CaCl2.After that, the group of EPS was studied by infrared spectrum which showed that polysaccharide,protein and DNA were the major components of EPS.Printing and dyeing wastewater was investigated by GC-MS technique. As a result eighty kinds of organic pollutants were detected including33kinds of alkanes and carboxylic acids,6kinds of lipids,3kinds of alcohols,2kinds of ketones and aldehydes,13kinds of amides,11kinds of benzene and phenols and22kinds of other classes.44kinds of organic pollutants were completely removed,but alkanes were removed ineffectively.Fluorescence emission and excitation matrix（EEM） were used to characterize the fluorescence of dissolved organic matters（DOM） in the treatment process.There were5peaks in the aqueous fingerprint such as tyrosine-like,tryptophan-like,lulvic-like, UV humus and lulvic.The total fluorescence intensity was reduced88.96%. The fluorescence intensity of Peak C,D,E were completely removed,but Peak A and Peak B were reduced85.49%and83.66%.The microbial diversity of treatment process of printing and dyeing wastewater was analyzed by PCR-DGGE technique.It was concluded that there were a variety of microorganisms and the microbial community’s succession was obvious. According to DGGE map and intensity diagram, select the bands with stronger signals for gel extraction and sequenced. Seven bands were selected. Pseudomonas stutzeri DF1SA belonged to Pseudomonas.Bacillus subtilis strain LY-001had strong adversity resisting property-in wastewater treatment. Zoogloea sp. UNPF74was able to form zoogloea, while Thalassobius mediterraneus belonged to a-proteobacteria. Beta proteobacterium NIO₀0091, Uncultured beta proteobacterium clone DSEP₉8and Thiobacillus denitrificans strain NBY57belonged to β-Proteobacteria which were important groups of wastewater treatment.