| Alkali-minimization dyeing printing industrial wastewater, which arose in 1980抯 and developed in 1990抯, is now one type of the popular industrial wastewater in China. In spite of the active research in this area, the alkali-minimization dyeing printing industrial wastewater quality and biodegradability are not yet well understood. No enough acknowledgement and experience about the treatment of the wastewater were obtained for engineering design. In this paper, comprehensive dyeing printing industrial wastewater, which was made up most by alkali-minimization dyeing printing industrial wastewater from Saoxing county, zhejiang province, was subjected to be monitored around a year and treated with different activated sludge process, and reports on the process and operation were given. Compared with traditional dyeing printing industrial wastewater, alkali- minimization dyeing printing industrial wastewater which was characterized with terephthalic acid (TA) as the principal pollutant, had much higher organic concentration, color and pH. The waste water quality varied widely with seasons, depending on the quantity and sorts of textile required in market, but usually had a high COD concentration of 780?116mg.V? B0D325-4346 mg.L? color 300?00(dilution ratio), pH 8.24-42.78, TA 28&?279 mg.JY? separately. Wastewater in which COD> lSOOmg.L?took up 54% of total wastewater around a year, pH> 10.0 the 90.4%. The ratio of COD:N:P was 100:0.58:0.24, which indicated the nutrient of N and P for microbe of bio-treatment were far less than the necessity. The biodegradability and COD removal rate of aerobic activated sludge were determined or estimated with B/C, COON (non-biodegradable COD), K~ (substrate half saturation constant), K (one-order reaction rate constant) and E0 (activation energy) in aerobic reactor. The results showed more than 80% COD could be removed, though the effluent could not meet the discharge standard. After anoxic pre-treatment, CODN was decreased 40?lOOmg.L? K increased 2?2%, and E0 decreased 26.6% during aerobic treatment, compared with that of single aerobic treatment. Anaerobic treatment could removed only 30?0% COD of the wastewater, but marked with high decolorization rate 60?0%, which was far more than that of aerobic or anoxic treatment. Some important factors affecting wastewater treatment, such as MLSS (Mixed Liquor Suspended Solid), DO (Dissolved Oxygen), temperature, pH and HRT (Hydraulic Retention Time) were optimized, while some semi-empirical formula were described. A increase of influent pH would led to a corresponding increase of mixed liquor pH, which influenced the microbial activity of activated sludge. Specific COD removal rate (U? was used to determine the performance of the activated sludge affected by different influent pH, while SV (Sludge Volume), SVI (Sludge Volume Index) and SS (Suspended Solid) of effluent were applied to judge the flocculability of activated sludge in aerating system. Some parameters, such as VFA (Volatile Fatty Acid) and III B/C, were used to illustrate the performance of the activated sludge in anoxie system. The results showed that it was necessary to control the mixed liquor pH below the limit of 9.4 in aerating system and 9.6 in anoxic system. The corresponding influent pH was below 10.5 and 11.5 respectively under experiment condition, otherwise, inhibitory effects on the activated sludge and sludge dispersion would be unavoidable to such an extent as to s...
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