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TREATMENT OF ACID MINE DRAINAGE USING ANAEROBIC CONSTRUCTED TREATMENT WETLANDS: PREDICTING LONGEVITY WITH SUBSTRATE NEUTRALIZATION POTENTIAL ROBERT C. THOMAS DANIEL P. COUGHLIN and DOUGLAS E. CROWE Abstract Anaerobic constructed treatment wetlands (CTW) have been shown to be an effective means of neutralizing acid mine drainage. The integrity of anaerobic CTWs is inherently rooted in the health of resident anaerobic microbial communities and it is the contaminant load delivered to the CTW that dictates the dominant community. Sizing recommendations have been developed based on contaminant loading from both a biotic and abiotic perspective; however these have failed to allow prediction of the CTW longevity. Since ultimately it is the buffering capacity of the substrate that sustains the healthy anaerobic microbial community, the total neutralization potential of a given volume of organic substrate may be used to predict the longevity of an anaerobic CTW. This method of prediction was tested in a column study and the results are evaluated in this presentation. Neutralization potential as a predictive tool is thought to be ineffective at high loading rates and low residence time where preferential flow may develop and at low loading rates and high residence time as the biologic oxidation of organic matter becomes increasingly significant. Over estimates may be made in the case of the former and under estimates in the case of the latter. Key Words: Anaerobic wetlands, Neutralization Potential, Predicting Longevity SREL Reprint #2430 Thomas, R.C., C.S. Romanek, D.P. Coughlin, and D.E. Crowe. 2000. Treatment of acid mine drainage using anaerobic constructed treatment wetlands: predicting longevity with substrate neutralization potential. p. 449-458. In Mining and the Environment II, edited by D. Goldsack, N. Belzile, P. Yearwood, and G. Hall. Laurentian University, Sudbury, Ontario, Canada.
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