環(huán)境工程專業(yè)英語文獻中英雙語版

1、Treatment of geothermal waters for production ofindustrial, agricultural or drinking waterDarrell L. Gallup ?Chevron Corporation, Energy Technology Company, 3901 Briarpark Dr., Houston, Texas 77042, USAReceived 14 March

2、2007; accepted 16 July 2007Available online 12 September 2007Abstract AbstractA conceptual study has been carried out to convert geothermal water and condensate into a valuable industrial, agricultural or drinkin

3、g water resource. Laboratory and field pilot test studies were used for the conceptual designs and preliminary cost estimates, referred to treatment facilities handling 750 kg/s of geothermal water and 350 kg/s

4、 of steam condensate. The experiments demonstrated that industrial, agricultural and drinking water standards could probably be met by adopting certain operating conditions. Six different treatments were examined. Unit p

5、rocesses for geothermal water/condensate treatment include desilication of the waters to produce marketable minerals, removal of dissolved solids by reverse osmosis or evaporation, removal of arse

6、nic by oxidation/precipitation, and removal of boron by various methods including ion exchange. The total project cost estimates, with an accuracy of approximately ±25%, ranged from US$ 10 to 78

7、 million in capital cost, with an operation and maintenance (or product) cost ranging from US$ 0.15 to 2.73m?3 of treated water.© 2007 CNR. Published by Elsevier Ltd. All rights reserved.Keywords: Key

8、words: Geothermal water treatment; Water resources; Desilication; Arsenic; Boron 1. 1. Introduction IntroductionWith the world entering an age of water shortages and arid farming land, it is increasingly important that w

9、e find ways of recycling wastewater. The oil, gas and geothermal industries, for example, extract massive amounts of brine and water from the subsurface, most of which are injected back into underg

10、round formations. Holistic approaches to water management are being adopted ever more frequently, and produced water is now being considered as a potential resource. In the oil and gas arena, attempts have been made to

11、 convert produced water for drinking supply or other reuses (Doran et al., 1998). Turning oilfield-produced water into a valuable resource entails an understanding of the environmental and economic implications, and

12、 of the techniques required to remove dissolved organic and inorganic components from the waters. Treatments of geothermal water and condensate for beneficial use, on the other hand, involve the removal of inorga

13、nic components only.We have explored the technical and economic feasibility of reusing Table 1Approximate geothermal water and steam condensate compositions assumed in the studya Total dissolved solids.Table 2Summary of

14、the six cases of geothermal fluid treatment to produce marketable watera On treatment of water, clays are produced at a rate of 7.4 ton/h.(FeAsO4·2H2O). In the laboratory and field pilot tests, the photo-absorber an

15、d UV dosages were varied to decrease the As concentration in geothermal fluids to below the detection limit of 2 ppb (Simmons et al., 2002). Residual As in the precipitate may be slurry-injected into a water

16、disposal well or fixed/stabilized for land disposal to meet United States Environmental Protection Agency (USEPA) Toxicity Characterization Leach Procedure (TCLP) limits using special cement formulations

17、 (Allen, 1996).3.2. Ion exchangeStrong-base anion exchange resins have been shown to remove traces of As in geothermal fluids provided that the amorphous silica is decreased below its saturation point o

18、r the water stabilized against silica scaling by acidification. The ion exchange alternative to As removal by oxidation/precipitation has proven successful in reducing the concentrations of this element to b

19、elow the limits set for drinking water standards. As part of the present study, laboratory and field columnar tests were successfully conducted with geothermal hot spring water containing 30 ppm As. Pre-oxidation

20、 of As3+ is required to achieve acceptable As removal by ion exchange. In these columnar tests, NaOCl and H2O2 were used to pre-treat the hot spring water to oxidize As3+ to As5+. Chloride-rich water, whic