Retention of manganese by a constructed wetland treating drainage from a coal ash disposal site
- Univ. of Pittsburgh, Johnstown, PA (United States). Biology Dept.
A 3,200 m{sup 2} wetland was constructed in 1988 to treat drainage from an ash disposal site at a coal-fired electricity generating plant in western Pennsylvania. Concentrations of Fe and Mn in the drainage range from 30--80 mg/L and 10--20 mg/L, respectively. Acidity levels of 60--180 mg/L and a pH between 5--5.6 are typical. The wetland has always produced a high quality effluent with respect to Fe concentrations (usually less than 1 mg/L) and pH (about 7). Initial performance of the wetland with respect to Mn was encouraging, with reductions in Mn concentrations of over 50% being common during the first six years of operation. The system was modified in 1994 by adding limestone riprap below some dams and covering diversion dikes with limestone. These alterations were followed by a significant improvement in Mn removal by the system, with effluent concentrations seldom exceeding 1 mg/L. Seasonal observations indicate that Mn removal in the wetland slows during the winter. In laboratory studies, wetland limestone increased Mn removal rates by as much as 6--7 times. These rates exhibited a temperature optimum of 27 C. The rate at near 0 C was about one half that at 27 C and the rate fell to near zero at 43 C. This suggests that biological activity associated with the limestone is an important factor in the success of this wetland.
- OSTI ID:
- 361646
- Report Number(s):
- CONF-9805185-; TRN: IM9933%%27
- Resource Relation:
- Conference: 15. American Society for Surface Mining and Reclamation (ASSMR) annual national meeting, St. Louis, MO (United States), 17-21 May 1998; Other Information: PBD: [1998]; Related Information: Is Part Of Proceedings of the 15. annual national meeting of the American Society for Surface Mining and Reclamation. Mining -- Gateway to the future; Throgmorton, D.; Nawrot, J.; Mead, J.; Galetovic, J.; Joseph, W. [eds.]; PB: 801 p.
- Country of Publication:
- United States
- Language:
- English
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