Study On Biological Aeration Filter Treating Of CMC Desizing Wastewater

In the increasing scarcity of water resources, effective treatment of wastewater control andreuse has become one of the feasible methods of water conservation. As a superpower of textiles,our country products a large number of textile printing and dyeing wastewater every year, whichcontains high concentration of pollutants especially the refractory organics, causes seriouspollution to the environment. Desizing wastewater accounts for a large amount of total water andcontaminants. Good desizing wastewater treatment and reuse is beneficial to protect the ecologicalenvironment and save water resources. CMC as one of the characteristic desizing wastewaterpollutants is also the difficulty of desizing wastewater treatment. How to deal with this wastewaterefficiently is the puzzle and challenge that the textile enterprises and researchers face currently.This researchused biological aerated filter(BAF) which is widely used in the field ofwastewater treatment to deal with CMC desizing wastewater. Both ceramic and activated carbonwere selected as the filter of BAF respectively. Under the same conditions, did the comparativeanalysis about the operating results of twoBAF, the superiority of two filters, and then selected themore suitable craft filter; at different gas-water ratio, hydraulic loading and other factors,investigated the operating results of the BAF process deal with CMC desizing wastewater as wellas the relationship between CMC degradation characteristics, microbiologic properties, microbialbiomass, activity and pollutants along the height direction; under the optimal condition, researchedthe removal ways of CMC and change rules along the way. The results of the research can providea theoretical and data reference for CMC removal research. Conclusions of this study are as follows:1. Under the same conditions, by comparing two BAFbiofilm formation and treatment effect ofpollutants, the ceramic BAF’s microbial biomass, removal rate of pollutants and degradationof CMC were better than activated carbon BAF’s. While activated carbon BAF’s adsorptionproperty was stronger and CMC desizing wastewater turbidity removal rate was better thanceramic. Comprehensively, the ceramic filter was more suitable for BAF CMC desizingwastewater treatment process.2. By adjusting gas-water ratio, hydraulic loading and other factors, analyzed the operationchange rule of BAF process, optimized the BAF optimalparaeters: gas-water ratio of4:1,hydraulic loading of0.071m3/(m2.h) around, pH between7.0and8.0, experimentaltemperature between20--30℃.3. Overall considering the two filters’removal rate about CMC, CODCrand turbidity at differentgas-water tatio and hydraulic loading, chose gas-water ratio of4:1, hydraulic loading of0.071m3/(m2·h), BAF process on the CMC desizing wastewater treatment worked best,when ceramic filter average removal rates of CODCr, CMC and turbidity were approximately72%,65%and82%, corresponding to an average of activated carbon filter removal rates wereabout67%,62%and84%.4. By analyzed the two BAF processes degradation change rules about CMC, CODCrandturbidity alongthe filter column height direction under different conditions, the main removalareas of CODCr, CMC and turbidity in BAF were located in the filter column that below theheight of1.5m,1.3m and1.1m respectively.Comprehensively analyzed BAF’height of highlyefficient removal rate of pollutants, it was reasonable to choose the filter height of not lessthan1.5m.5. Detected membrane biomass by lipid-phosphorus method and measured microbial activity byTTC-dehydrogenase activity method.The microbial biomass and activity of the two BAF hadthe similar variation, the content and activity of microbial in filter along the process of thefilter were inversely proportional to the height of filter, and the bottom of filter had the largestmicrobial biomass and activity.6. According to the pertinence analysis between microbial biomass, microbial activity and concentration of CMC and CODCrin each section along the filter column, the concentration ofCMC and CODCrin each section had a high linear correlation with microbial biomass andactivity, while the linear correlation between turbidity and microbial biomass, activity was low,the change of CMC and CODCrhad an obvious influence with microbial biomass and activity,and the interactions between turbidity and microbial biomass and activity were small.7. In BAF process, the main removal effects of CMC were biological adsorption andbiodegradation, and the removal mainly rely on biological adsorption,1#filter biodegradationratio accounted for23.2%,2#filter biodegradation ratio only accounted for16.3%. In the twobiofilters, the CMC biodegradation only accounted for34.7%and26.1%of CMC totalremoval rate respectively.8.0.9m following areas of the two filters were efficient adsorption areas of CMC. Adsorptionratio of1#and2#filter in this region accounted for about90%of total adsorption rate. As theheight increased, the amount of CMC adsorption decreased. In the filter column of0.9mfollowing areas would have a lot of CMC that enriched, so it was favorable to maintain a highHRT for CMC efficient degradation.