Biological processes for the treatment of waste water from coal-fired power plants
In The Netherlands, all coal-fired power stations are equipped with a wet lime(stone)-gypsum flue gas desulfurization (FGD) installation, in order to meet the SO{sub 2} emission requirements. During wet desulfurization a waste water stream is produced containing among others suspended solids, heavy metals, nitrate and in some cases ammonia. Besides, the chemical oxygen demand (COD) of the waste water is increased if the FGD process is optimized by application of organic buffers. The traditional waste water treatment plant (WWTP) does not remove nitrate, ammonia and COD, and only poorly removes the anions of oxygenated metals such as selenium. In a previous research it was demonstrated that nitrate and ammonia can be removed biologically, even at the relatively extreme conditions of FGD waste water, which is characterized by a high chloride concentration (5 and 40 g/l) and relatively high temperatures (typically 35--50 C). However, the removal is no longer solely focused on nitrogen components, but also on COD removal and for the anions of some oxygenated metals target values are expected in the near future. In this paper attention is focused on two biological processes. One process is the combined removal of nitrate and COD in a fluid-bed reactor which can be applied upstream of the traditional WWTP. The application of this process was successfully demonstrated at a bench-scale fluid bed reactor. The optimal process conditions were determined in activated-sludge reactors on a laboratory scale. The second biological process is the combined removal of COD and metals from FGD waste water. An upflow sludge blanket reactor was successfully tested on laboratory scale at a wide range of process conditions with actual waste water. The possible advantages and disadvantages of the biological removal processes are discussed and compared with the well known chemical precipitation process.
- Research Organization:
- KEMA, Arnhem (NL)
- OSTI ID:
- 20018953
- Report Number(s):
- CONF-9806214-; TRN: IM200018%%187
- Resource Relation:
- Conference: Power-Gen Europe'98, Milan (IT), 06/09/1998--06/11/1998; Other Information: 1 CD-ROM. Operating Systems: Windows 3.1, '95, '98 and NT; Macintosh; and UNIX; PBD: [1998]; Related Information: In: Power-gen Europe'98, [2400] pages.
- Country of Publication:
- United States
- Language:
- English
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