外文翻譯--電解處理啤酒廢水（英文）

1、Electrolytic Treatment of Beer Brewery WastewaterKrishnan Vijayaraghavan,* Desa Ahmad, and Renny LesaDepartment of Biological COD, 64 mg/L; biochemical oxygen demand (BOD5), 30 mg/L; total organic carbon (TOC), 40 mg/L;

2、 residual total chlorine, 162 mg/L; turbidity, 20 NTU (nephelometric turbidity units); ammonia nitrogen (NH3-N), below the detectable limit; and temperature, 40 °C. The energy requirements were determined to be 56 a

3、nd 39 W/L, while treating 24 L of beer brewery wastewater with sodium chloride concentrations of 2% and 3% and at a current density of 74.5 mA/cm2. The observed energy difference was due to the improved conductivity at h

4、igh sodium chloride contents. The cost incurred in treating 1 m3 of beer brewery wastewater was determined to be RM 8, when the electrolytic reactor was operated at a current density of 74.5 mA/cm2 and the sodium chlorid

5、e content was 3%.1. IntroductionBecause the conventional method of beer brewery wastewater treatment is based on biological methods, it naturally leads to longer hydraulic retention time and is subject to failures due to

6、 shock loading and improper maintenance. Moreover, the biodegradation of flavonoids present in the brewery requires specific bacterial strains to achieve higher removal efficiencies. The electrochemical method of treatme

7、nt is well-suited for degrading biorefractory organic pollutants, because it is pos- sible to achieve partial or complete decomposition of the or- ganic substance. The electrochemical methods of treatment are favored, be

8、cause they are neither subject to failures due to variation in wastewater strength nor due to the presence of toxic substances and require less hydraulic retention time. The in situ generation of hypochlorous acid in was

9、tewater treatment is advantageous, because aqueous solutions of sodium hypochlorite are much safer to use than chlorine gas. In the case of chlorine or chlorine-containing chemicals, the storage and transportation costs

10、are great, because of the requirement of having safety equipment present, to tackle any mishap. The electrochemical method of waste treatment came into existence when it was first used to treat sewage generated onboard b

11、y ships, by mixing sewage and seawater in a 3:1 ratio and subjecting them to electrolysis.1 Thereafter, the application of electrochemical treatment was widely received in treating industrial wastewaters that are rich in

12、 refractory organics and chloride content. Electrochemical oxidation of effluents from textiles,2-6 olive mills,7,8 tanneries,9-11 distilleries,12 and syntan facilities13 had been successfully treated. The electrochemica

13、l oxidation of swine manure resulted in the simultaneous removal of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N).14 The electrochemical oxidation of phenol and chlorinated phenol was studied using porous car

14、bon felt,15 boron- doped diamond,16 ruthenium mixed oxide,17 DSA, and graphite felt as electrode material.18To the best of our knowledge, there are no published scientific reports that are based on in situ hypochlorous o

15、xidation for beer brewery wastewater. Hence, in this article, electrolytic oxidation based on in situ hypochlorous acid generation is being proposed as a method of treatment for beer brewery wastewater. The hypochlorous

16、acid is generated using a graphite anode and stainless steel sheet as a cathode in an undivided electrolytic reactor. The beer brewery wastewater was obtained from the Carlsberg Brewery Malaysia Berhad.2. Material and Me

17、thods2.1. Beer Brewery Wastewater Characteristics. The raw beer brewery wastewater was collected from the Carlsberg Brewery Malaysia Berhad, and the characteristics of the wastewater are presented in Table 1. The brewery

18、 wastewater was preserved at a temperature of <4 °C, but above the freezing point, to prevent the wastewater from undergoing biodegradation due to microbial action.19 The preserved sample was utilized within 25 d

19、; thereafter, fresh samples were collected for further experimental purposes. 2.2. Electrolytic Reactor Setup. The electrolytic reactor had a circular shape with the following dimensions: an inner diam- eter of 300 mm an

20、d a height of 450 mm, with a liquid volume of 24 L, as shown in Figure 1. A graphite rod 270 mm in length and 60 mm in diameter was used as an anode. Perforated stain- less steel sheets 270 mm long, 50 mm wide, and with

21、a thickness of 0.8 mm were used as cathodes. Two sets of anodes and cathodes were used during the electrolysis. Each set of graphite* To whom correspondence should be addressed. Tel.: 00-603- 89466416. Fax: 00-603-8946 6

22、425. E-mail address: vijay@ eng.upm.edu.my.Table 1. Characteristics of Raw Beer Brewery Wastewaterparameter valuepH 8.5 ( 0.2 concentration of COD 2470 mg/L concentration of BOD 1457 mg/L concentration of TOC 820 mg/L co

23、ncentration of TKN 97 mg/L concentration of NH3-N 62 mg/L concentration of phosphate 56 mg/L concentration of suspended solids 350 mg/L6854 Ind. Eng. Chem. Res. 2006, 45, 6854-685910.1021/ie0604371 CCC: $33.50 © 200

24、6 American Chemical Society Published on Web 08/23/2006current density of 37.2 and 74.5 mA/cm2 and for sodium chloride concentrations of 1%, 2%, and 3%. For example, at a current density of 37.2 mA/cm2 for sodium chlorid

25、e contents of 1%, 2%, and 3%, at the end of 30 min of electrolysis, the residual COD values were 1405, 915, and 730 mg/L, respec- tively. In the case of electrolysis at a current density 74.5 mA/cm2 for the aforementione

26、d sodium chloride contents and electrolysis period, the residual COD values were 1130, 470, and 360 mg/L, respectively. Further increases in the electrolysis period showed a decrease in residual COD concentration, irresp

27、ective of the current densities. In the case where 3% sodium chloride was used as an electrolyte at a current density of 37.2 and 74.5 mA/cm2, for an electrolysis period of 50 min, residual COD concentrations of 170 and

28、64 mg/L, respectively, resulted. At higher current densities, more hypochlorous acid was generated, leading to the oxidation of organic present in the wastewater in shorter period.The residual BOD5 concentration versus t

29、he electrolysis period is shown in Figure 4 for current densities of 37.2 and 74.5 mA/cm2 at sodium chloride concentrations of 1%, 2%, and 3%, respectively. As shown in Figure 4, with the increase in current density resu

30、lted in lower residual BOD5 concentration. For example, at the end of 50 min of electrolysis with 3% sodium chloride as an electrolyte for current densities of 37.2 and 74.5 mA/cm2, the residual BOD was determined to be

31、90 and 30 mg/L, respectively.The TOC removal during the electrolysis period is shown in Figure 5 for current densities of 37.2 and 74.5 mA/cm2 at a sodium chloride concentration of 1%, 2%, and 3%, respectively. As the el

32、ectrolysis period increased, the TOC also decreased, and a higher removal in TOC was observed with the increase in current density. For example, at the end of 50 min of elec- trolysis with 3% sodium chloride as an electr

33、olyte for current densities of 37.2 and 74.5 mA/cm2, the residual TOC was deter- mined to be 94 and 40 mg/L, respectively. For the aforemen- tioned electrolysis period and sodium chloride content at a cur- rent density 3

34、7.2 mA/cm2, the COD/TOC ratio decreased from 3.0 to 1.8. In the case where the current density was 74.5 mA/cm2, the COD/TOC ratio decreased from 3.0 to 1.6, respectively. The decrease in COD/TOC ratio shows that the carb

35、on was destroyed, because of the oxidizing action of the generated hypochlorous acid. In the case of phenol-formalde- hyde resin wastewater, treatment based on hypochlorus oxidation resulted in a decrease in the COD/TOC

36、ratio, from 4.3 to 1.3.22Electrochemical oxidation of the effluents originated from flavor manufacturing facility showed a decrease in COD/TOC ratio from 3.3 to 1.7.23The total residual chlorine concentration during the

37、elec- trolysis period is shown in Figure 6, for an initial COD concentration of 2470 mg/L at varying sodium chloride content (1%, 2%, and 3%) and at a current density of 37.2 and 74.5 mA/cm2. For example, at a current de

38、nsity of 37.2 mA/cm2 for sodium chloride contents of 1%, 2%, and 3%, at the end of 30Figure 3. Residual chemical oxygen demand (COD) concentration versus electrolysis period.Figure 4. Residual biochemical oxygen demand (

39、BOD5) concentration versus electrolysis period.Figure 5. Residual total organic carbon (TOC) concentration versus electrolysis period.Figure 6. Residual total chlorine concentration versus electrolysis period.6856 Ind. E