| At the present, the most of terephthalic acid and ethylene glycol from alkali-deweighting and dyeing-printing wastewater would be treated by the general biological treatment methods. Howerver, there were some varieties of small molecular oligomers from the alkali-deweighting process, and a portion of complex organic produced from the other processes of polyester fabrics production such as dyes, pulps, additives, which were very difficult degradable materials dissolved in alkali-deweighting and dyeing-printing wastewater and then increase the difficulty to treat. Finally, the traditional biological metheds could not be satisfied with the treatment of alkali-deweighting and dyeing-printing wastewater. Therefore, it was still a vital research field among the environmentists to find one of the efficient processes with the advantages of simple operation, inexpensive operating cost and high removal efficiency.Alkali-deweighting and dying-printing wastewater was treated by anaerobic baffled reactor (ABR) in this research. Including as follows:the strat-up of ABR to treat alkali-deweighting and dying-printing wastewater, the optimal operation parameters determined with orthogonal experiment, the influence of effluent recycle on treating alkali-deweighting and dying-printing wastewater by ABR, and biological separation of ABR was studied on.The experimental results showed as follows:(1) Seeding with the anaerobic granular sludge, the start-up with low organic loading was started by using alkali-deweighing and dyeing wastewater as influent on the condition of temperature32℃-35℃, pH7.8-8.3and hydraulic retention time (HRT)=36h. After continuously running70days, the start-up had been completed to reach the stabilization. The results showed that the pH of effluent kept stable around7.3and the average COD removal rate was up to78%while the average volume loading rate was1.93kg·(m3·d)-1. After the start-up, a separating function of each compartment was observed and meanwhile the anaerobic granular sludge with good properties was achieved. Relative to the start, the size of granular sludge particle was increased and the sludge sedimentation performance became better and the value of f (MLVSS/MLSS) was up to0.65at the end of the experiment. In addition, high activity of the microorganism was observed that the average value of dehydrogenase activity (DHA) with TF expression and the coenzyme F420concentration was88.8μg·(g·h)-1and0.18μmol·g-1respectively.(2) After continuously running145days’ orthogonal experimental design, single index and double index analysises of COD and UV254removel through HRT, inlet alkalinity and ascending velocity influence factors were studied. The results showed as follows:HRT was one of the largest influential factors to the single index of COD removal rate, and second influential factor was ascending velocity and last influential factor was inlet alkalinity, the optimal operation parameters of COD removal rate single index was HRT=24h, inlet alkalinity=125mg/L and ascending velocity=1m/h. Furthemore, the influential factor of ascending velocity as well as HRT had play a vital role on the UV254removal rate, and second influential factor was inlet alkalinity, the optimal operation parameters of UV254removal rate single index was HRT=36h, inlet alkalinity=125mg/L and ascending velocity=10m/h. After the comprehensive analysises of double index, the optimal operation parameters was HRT=24h, inlet alkalinity=125mg/L and ascending velocity=10m/h.(3) Under the condition of HRT=24h and inlet alkalinity=125mg/L, contrast experiment between ABR1with effluent recycle system and ABR2without effluent recycle system to research the influences of the effluent recycle to treat the alkali-deweighing and dyeing wastewater with the ABR. The results showed as follows:the ABR1with effluent recycle system required an adjusttment period. After reached the stable state, COD removal rate of ABR1was maintained72.8%, which was slightly larger than COD removal rate=70.4%of ABR2. The average B/C ratio=0.68of ABR1effluent was lager than the The average B/C ratio=0.65of ABR2effluent. Therefore, the biochemical ability of ABR was increased by effluent recycle.The average pH of ABR1effluent was maintained around7.4which was slightly lower than the average pH=7.4of ABR2. A favorable environment of oxido-reduction was provided for the methanogenesis by the effluent recycle system. The effluent recycle was benficial to the removing of colority, but the effluent turbidity was increased.(4) Through the analysises of the compartmental microbial activity and microbial morphology, biological separation of the achieved start-up ABR was studied on ABR achieved the start-up. The results showed that enzyme activities in each compartment were increased with the decreasae of HRT, particllarly the dehydrogenase activity. Meanwhile, There was obvious diversity of the DHA and coenzyme F420activity in each compartment, Which indicated that the distinction of the compartmental function in ABR was also obvious. By the component analysises of biogas in each compartment, the results showed that CO and H2were main component in compartment1and compartment2of biogas, and CH4was main component in compartment3and compartment4of biogas. In addition,there were abundant microorganism in the achevied start-up ABR and the advantaged strains had been set up in each compartment, which methanbacterium alcaliphilum and hydrogen-producing acetogenic bacteria were advantaged strains in the front compartment and then the consequent compartments, especailly in the compartment3and4, were based on archaebacteria. Therefore, ABR had the function of biological separation. |
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