外文翻譯---在啟動過程中加裝膜生物反應(yīng)器的氧化溝的性能

1、 - 1 -Performance of an oxidation ditch retrofitted with a membrane bioreactor during the start-upABSTRACT The objective of this study is to elucidate the full-scale characteristics of an oxidation ditch (OD) retrofitted

2、 with a membrane bioreactor (MBR). Domestic wastewater entering an oxidation ditch at a flow rate of 86 m3/d was directed to a MBR retrofitted into the original secondary sedimentation tank. The MBR contained flat sheet

3、membranes. The data collected for 2 months during the start-up of the system showed that pH was maintained at 7.2 and 6.7 in OD and MBR, respectively. Dissolved oxygen (DO) in MBR remained stable at 7.8 mg/L, while fluct

4、uated in OD. The mixed liquor suspended solids (MLSS) in the OD remained steady at a concentration about1000 mg/L, but it was gradually building up from 500 mg/L to 2400 mg/L in the MBR during this period.Measurements of

5、 carbohydrate and protein were made by extracting the extra cellular polymeric substances (EPS)with sodium hydroxide (NaOH) from the mixed liquor obtained from both OD and MBR. Carbohydrate was predominant in the EPS and

6、 the ratios between carbohydrate and protein converged to fixed values from the fourth week; in this case the ratio was 4.5 for OD and 5 for MBR. The variation in EPS contents showed similar trends in both OD and MBR. Th

7、e integrated treatment facility removed ammonia, COD and BOD at 100、91.6 and 97.0%, respectively. However, efficiency of nitrate and phosphate removal has not been realized yet.KEYWORDS: Oxidation ditch; Submerged flat s

8、heet membrane; Extracelluler polymeric substance; Nutrient removal- 3 -solids concentrations and requires large land area [4].Nu0ria Vidal and co-workers (2002) compared the difference among three wastewater treatment pr

9、ocesses including; (1) activated sludge process, (2) Ludzack–Ettinger (anoxic process followed by aeration process) and (3) Oxidation ditch [5]. For each of the three scenarios, the emissions and the use of na

10、tural resources due to their operation and transportation of sludge were evaluated. Consumption values for all energy resources were higher for the Ludzack–Ettinger configuration, while the values from the

11、 oxidation ditch configuration did not differ significantly from the activated sludge. Major environmental impact by eutrophication due to NH4+ /NO3-was reduced by 68% in the Ludzack–Ettinger configuration and 75% in the

12、 oxidation ditch configuration with respect to the reference activated sludge process [5].However, the quality of effluent from oxidation ditch is not sufficient enough for higher standards that are required for unlimite

13、d irrigation and reuse of the water. Membrane bioreactor (MBR) technology has been applied to provide high quality effluent by constructing a membrane system into the existing clarifier.The benefits of using the

14、MBR technology for retrofiting are no extra land requirement, produces high quality effluent for reuse, no odor, and allows treatment of much higher capacity of wastewater [6]. A full scale oxidation ditch retrof

15、itted with a membrane bioreactor is in operation in Kilkenny Ireland since 1999 to treat 9000 m3/d of dairy farm wastewater [6].The purpose of this study is to characterize the performance of a full-scale OD retrofitted