The Study Of Advance Treatment Of Bleaching And Dyeign Wastewater By Cass And Mathematical Model

The present situation and the study progress on advance treatment of the dyeing wastewater is rerviewed, and the characteristics, principles and applications of Cyclic Activated Sludge System (CASS) briefly introduced. The experiment eploys the technique of CASS to further treat the bleaching and dyeing wastewater, and establishes the corresponding dynamics mathematics model. The main results are summarized as follows:1. The experiment indicated that the CASS's treating effect is the best when HRT is 15.5h, MLSS 1071mg/L, COD Sludge load 0.21 kgCOD/(kgMLSS·d), the influent COD 112~194mg/L, with the effluent COD being 49.0~58.7mg/L, removal rate between 52.5% and 70.8% steadily, average removal rate 62.12%, and effluent COD below 60mg/L.2. Under various influent concentration of wastewater,the COD removal rate kept stable, along with the reaction time, which proved the CASS system anti-impact load is specially remarkable. Moreover, the quality of water can be effectively controlled via adjusting reflux ratio of sludge. It was found the influent time played key role to the quality of effluent water. The longer the influent time, the slower the organism being added, the better the removal effect of unsoluable organim.Further more, the long influent time contribute to the formation of flocculence bacterium in the biological selector and the hydrolyzition and acidification of the organism in the anoxic zone.3. The experiment results showed that the degradation velocity obeys one class reaction kinetics. After 5 hours'aeration, soluble organic compound degraded almost completely, and organic compound difficultly to degrade remained. COD biodegradation rate only 60.7, which manifested that the necessity of hydrolyzation and acidification, and the feasibility of chemical-physical method for the effluent of CASS.4. The COD removal effect of poly-aluminum chloride coagulant surpasses that of the aluminium sulfate.With best dosage about 100 mg/L, removal rate is about 20%, not significant. However, both of the two coagulants display little influence on the wastewater chromaticity. 5. After the secondary effluent of bleaching and dyeing wastewater treated by CASS, it still contained a few dyes which enable it to have certain chromaticity of buff color. Moreover some inorganic salt like Na2SO4, NaCl are unable to be removaled. Therefore, the effluent water was only fit to be reused in such working procedure like boil practices and rinse with relatively low water quality request, which would not only reduce the production water supply, but also may reduce the wastewater emissions. Thus the technique of CAAS is practical and feasible for dyeing factories.6. This experiment aimed to serve the practical treatment to secondary effluent of bleaching and dyeing wastewater. In terms of COD removal rate, color removal effect, reliability, water quality, the investment, the operation expense, and the management etc., CASS is a quite practical and feasible wastewater treating method, which is superior to other means. Therefore, CASS technique has promising application prospect.7. This article has carried on the discussion to dynamics model of CASS, estimated dynamics parameters, caculated the mathematical model with Matlab to optimum the design parameters, which is important to the practical application of CASS in treating the dying wastewater.