Study On The Treatment Of Papermaking Wastewater And Its Typical Pollutants With Internal Circular Reactor

Papermaking industry plays an important role in national economy. But to develop paper industry, the treatment technology should be researched and applied to engineering practice,which can reduce or even eliminate the damage to the ecology. IC (Internal circulation) anaerobic reactor is a new style and high efficiency anaerobic reactor. It can be operated at high volume loading rates with low investment cost and space occupation. The paper studied on the feasibility, efficiency, and function of papermaking wastewater and its typical contaminants treatment with an IC anaerobic reactor. The contents included start-up test of Synthetic wastewater of glucose, treatment test of OCC (Old corrugated cardboard) papermaking wastewater, research of organic degradation dynamics model and anaerobic degradation test of DBP (di-n-butyl phthalate).The study on the performance of the IC reactor showed that the start-up of IC reactor at the volumetric loading rate of 3 kgCOD·m-3d-1 could be finished in79d,the reactor performed wel,the volumetric loading rate increased from 1.55 kgCOD·m-3d-1 to 14.41 kgCOD·m-3d-1, the HRT (Hydroli Retention Time) shortened to 4.8h and the COD (Chemical Oxygen Demand) removal was above 90%. During the test, pH in influent was 6.8~8.0, pH in effluent was 6.0~7.0, VFA (Vilotilize Fatty Acid) was 64.8~382.32mg/L and gas production was 4.5~45.1L/d.Anaerobic resolvability test of OCC papermaking wastewater revealed that the BD of OCC papermaking wastewater is 84.33%. And it has better anoxygenic resolvability, which is fit for method of aerobic.After 65 days of continuous operation the result revealed that the temperature, COD concentration in influent, COD removal efficiency, COD loading, gas production, SS (Suspended Substance) concentration in effluent, pH in influent and in effluent and VFA in effluent were 18~29℃, 1163~2809 mg/L, 64.19~93.81%, 2.57~8.03 kgCOD·m-3d-1, 9.56~29.30 L/d, 18mg/L~116mg/L, 5.2~8.32, 6.3~7.0 and 102~347 mg/L respectively, during operation. The gas production have correlation with COD loading, and when temperature was below 20℃there were effects of temperature on COD removal efficiency and gas production.The paper carried through analysis and deduction of organic degradation dynamics model for IC reactor, and elicited two dynamic equations. The first reaction zone can be used the formula to describe, while the second reaction zone can be used the formula to describe. K1 and K2 could be measured by the experiment data regression analysis. And then we could finally get results of values that K1=1.391h-1, K2=0.223h-1, the correlative coefficient R12=0.9161, R22=0.8751.Anaerobic degradation test of DBP revealed that when the proportion of DBP was 20%, DBP concentration in influent was 200 mg/L), DBP removal efficiency was best, removal efficiency was 80%. when the proportion was 15% the volume of gas production and Methane were largest,they were 25.16 L/d, 17.42 L/d, respectively. DBP and COD removal below 75cm accounts for about 85%,80% of the total removal. During the test, DBP removal, COD removal, pH and VFA in effluent were 44.6~81.30%,69.89~93.70%,6.46~7.13,149~356 mg/L, respectively, the volume of gas production and Methane were 6.03~26.01 L/d,4.2~18.23 L/d. Methane was accounts for 64.05~72.53% of total gas production.Anaerobic degradation products of DBP was analyzed through GC-MS, and it showed that degradation pathway of DBP was firstly converted into monoester then into phthalic acid and benzoic acid and finally oxidized into CO2 and H2O.