外文翻譯--采用缺氧折流板反應(yīng)預(yù)處理紡織印染廢水（英文）

1、Short CommunicationPretreatment of textile dyeing wastewater using an anoxic baffled reactorAvishai Sintov a,Tomer Avramovich ba Division of Advanced Materials Engineering, RCIT, Chonbuk National University, Jeonju 561-7

2、56, Republic of Koreab Department of Materials Engineering, University of British Columbia, Vancouver, Canada Received 16 November 2007; received in revised form 15 February 2008; accepted 18 February 2008Available onlin

3、e 2 April 2008AbstractA study on pretreatment of textile dyeing wastewater was carried out using an anoxic baffled reactor (ABR) at wastewater temper- atures of 5–31.1 ?C. When hydraulic retention time (HRT) was 8 h, the

4、 color of outflow of ABR was only 40 times at 5 ?C and it could satisfy the professional discharge standard (grade-1) of textile and dyeing industry of China (GB4287-92). The total COD removal effi- ciency of ABR was 34.

5、6%, 47.5%, 50.0%, 53.3%, 54.7% and 58.1% at 5, 9.7, 14.9, 19.7, 23.5 and 31.1 ?C, respectively. Besides, after the wastewater being pre-treated by ABR when HRT was 6 h and 8 h, the BOD5/COD value rose from 0.30 of inflow

6、 to 0.46 of outflow and from 0.30 of inflow to 0.40 of outflow, respectively. Experimental results indicated that ABR was a very feasible process to decolorize and pre-treat the textile dyeing wastewater at ambient tempe

7、rature. Moreover, a kinetic simulation of organic matter degradation in ABR at six different wastewater temperatures was carried through. The kinetic analysis showed the organic matter degradation was a first-order react

8、ion. The reaction activation energy was 19.593 kJ mol?1 and the temperature coefficient at 5–31.1 ?C was 1.028. ? 2008 Elsevier Ltd. All rights reserved.Keywords: Textile dyeing wastewater; Anoxic baffled reactor; Hydrol

9、ysis pretreatment; Degradation kinetics; Temperature coefficient1. IntroductionOver 7 ? 105 metric tones of synthetic dyes are produced worldwide every year for printing and dyeing and 5–10% is discharged with wastewater

10、 (Vaidya and Datye, 1982; Yu et al., 2001). There are some dyestuff, slurry, dyeing aid, acid or alkali, fiber and inorganic compound in textile dye- ing wastewater. Furthermore, some dyestuff contains nitryl, amidocyano

11、gen and heavy metals, such as copper, chrome, zinc and arsenic and so on. Besides, the components will be changed because of different dyestuff category, dyeing pro- cess, dye concentration and equipment scale (Delee et

12、al., 1998). Generally, the textile dyeing wastewater is character- ized by strong color, high pH, high COD, and low biode- gradability (Liakou et al., 1997). So the textile dyeing wastewater from textile industry is an i

13、mportant source ofenvironmental contamination (Joo et al., 2007). With stabil- ity and difficulty degradation by microorganism, it is diffi- cult to meet the discharge criterion only using simple biological treatment pro

14、cesses, while physical chemistry treatment processes need high operation expense (Pearce et al., 2003). At present, researchers gradually have found new treatment processes, one of which the wastewater is firstly hydroly

15、zed under anoxic condition, and then is trea- ted under aerobic condition (Lourenco et al., 2000; Yu et al., 2000). Anoxic hydrolysis–aerobic treatment of textile dyeing wastewater has been considered to have some advan-

16、 tages over the conventional processes. For anoxic condi- tion, the hydraulic retention time (HRT) is short, and non-degradable organic compounds of wastewater can be transformed into degradable matter, i.e., the degrada

17、ble performance of the wastewater is improved greatly. Simul- taneously, the color and a portion of COD can be removed. Anoxic baffled reactor (ABR) as a hydrolysis process was adopted in this study. There were several s

18、mall0960-8524/$ - see front matter ? 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2008.02.026* Corresponding author. Tel.: +972 54 5562555. E-mail addresses: sintova@bgu.ac.il (A. Sintov), ashapiro@bgu

19、.ac.il (A. Shapiro).Available online at www.sciencedirect.comBioresource Technology 99 (2008) 7886–78913. Results and discussion3.1. Hydraulic characteristics of the reactorAs already mentioned in the part of ‘‘Methods”

20、, the hydraulic characteristics were measured in ABR without biomass. At HRT of 8 h, the obtained distribution of the residence time in the reactor (so-called RTD curve) is shown in Fig. 1. h is a reduced time.h ¼ t

21、s ; ð1Þwhere t is the real time (min) and s is the theoretical mean residence time (min). The variable C expresses the ratio C = c/c0, where c is the tracer concentration in the effluent (mg L?1) and c0 is the

22、concentration of the tracer that could be obtained if the amount of the tracer added to the reactor got dis- persed throughout the whole reactor volume (mg L?1). In this case of distribution (C = f(t)), the two more impo

23、rtant results of RTD curve studies, experimental mean residence time and the variance, can be given. The experi- mental mean residence time te (min), can be calculated by Eq. (2) and the variance r2 t , can be calculated

24、 by Eq. (3).te ¼R 10 tf ðtÞdtf ðtÞdt ; ð2Þr2 t ¼R 10 ðt ? teÞ2f ðtÞdt R 10 f ðtÞdt ¼R 10 t2f ðtÞdt R 10 f ðtÞdt ? t2 e; ð

25、;3ÞBesides RTD curve, the system is characterized by the dispersion number (D/ul). For hydraulically closed system, the dispersion number can be calculated from the relationr2 t t2 e ¼ 2 DuL ? 2 DuL? ?2 ð1

26、 ? e?uL=DÞ; ð4Þwhere D is the longitudinal dispersion coefficient (m2 s?1), u is the mean flow velocity through the reactor (m s?1), and L is the length of the tank (m).In the experiment, NaCl mass balance

27、 was calculated and its deviation was 2.86%. The dispersion number (D/ ul) of the ABR was equal to 0.09. So the actual flow type of the reactor was intervenient between ideal piston flow and ideal complete mixing flow, b

28、ut it was close to piston flow more. Besides, the ABR run at anoxic condition and the gas production was so small that the influence of gas stirring on the flow could be ignored. Thus the flow type of the ABR could be as

29、sumed to be a piston flow in this study.3.2. Performance of the ABR3.2.1. Color removal Apparent color of sample from each compartment in ABR at six different wastewater temperatures is listed in Table 2. At the same was

30、tewater temperature, along with increase of the serial number of compartment, the apparent color of sample grew paler gradually. While at six different wastewater temperatures, the higher the wastewater tem- perature was

31、, the paler the apparent color of sample from the same compartment was. And the apparent color of sample from compartments 5 to 6 was similar and approached straw yellow. To determine the color removal efficiency, quanti

32、tative analysis of color concentrations of samples was conducted in this study. Color and color removal efficiency of each compartment in ABR are shown in Fig. 2. Along with increase of the serial number of com- partment

33、, the color of sample dropped gradually. And in all compartments, the most falling scope of color appeared in compartment 1 and the color removal efficiency was 40%, 60%, 80%, 80%, 81% and 85% at 5, 9.7, 14.9, 19.7, 23.5

34、 and 31.1 ?C, respectively. Moreover, along with the increase of wastewater temperature, the color of outflow from ABR grew lower. When wastewater temperature was higher than 9.7 ?C, the color removal efficiency of out-

35、flow reached 90% above. Even at low wastewater tempera- ture of 5 ?C, the color of outflow was only 40 times. Thus we could draw a conclusion that ABR was a good process to decolorize the textile dyeing wastewater at amb

36、ient tem- perature. Only pre-treated by ABR at 5–31.1 ?C, the color of outflow could satisfy the professional discharge standard (grade-1) (color 6 40 times) of textile and dyeing industry of PR China (GB4287-92).3.2.2.

37、COD removal COD and COD removal efficiency of each compartment in ABR are shown in Fig. 3. At the same wastewater tem- perature, the COD of compartment in ABR decreased gradually along with increase of the serial number

38、of com- partment, and the COD removal efficiency rose continu- ously. COD reduction in compartments 1–6 exited the following relation: most in compartment 1 (except 5 ?C), secondary in compartments 4–5, tertiary in compa

39、rtments 2–3, and least in compartment 6. The main reason was that a portion of COD in wastewater was adsorbed and the degradable organic matter was decomposed firstly by0.0 0.5 1.0 1.5 2.0 2.50.00.20.40.60.81.01.2CθFig.