Constructed Wetlands for Minewater Treatment: Performance and Sustainability

Abstract

Wetlands were constructed between 1995 and 1999 to treat discharges from abandoned coalmines in the Pelenna Valley, South Wales. This was one of the first and most comprehensive demonstrations of passive minewater treatment technology in Europe, incorporating aerobic and anaerobic cells, including ‘reducing and alkalinity‐producing systems. The wetlands were monitored to assess their performance and longevity and were found to remove 82‐96% of the incoming iron, with no decline in treatment performance over the monitoring period to 2002. Oxidation was found to be the dominant iron‐removal process, even in vertical‐flow cells which were designed to utilise anaerobic processes. Factors limiting the longevity of iron‐removal processes were identified. maintenance requirements were highlighted and life‐span predictions were calculated for the systems. The wetlands were shown to be an effective and low maintenance (but not maintenance‐free) method of treating net‐acidic and net‐alkaline minewater.

Contaminations of Soil and Two Capsicum annuum Generations Irrigated by Reused Urban Wastewater Treated by Different Reed Beds

“…Iron is removed by oxidative processes and iron hydroxide creation [ 24 , 25 ]. However, biotic processes involving bacteria in iron oxidation can also be important [ 25 ].…”

Passive Sequestration of Atmospheric CO2 through Coupled Plant-Mineral Reactions in Urban soils

“…In the treatment of contaminated waters, constructed wetlands (reed beds) can be used as a passive remediation process . These rely on natural processes to remove dissolved contaminants, and also to remove suspended solids.…”

“…In the treatment of contaminated waters, constructed wetlands (reed beds) can be used as a passive remediation process. 45 These rely on natural processes to remove dissolved contaminants, and also to remove suspended solids. They have very low energy inputs and relatively low maintenance costs compared with industrial plant and equipment, and are suitable for treating chronic and geographically isolated pollution sources.…”

Characterization of Iron Oxides From Abandoned Mine Drainage Discharges

“…Oxidation ponds are utilized to remove iron in the form of iron oxides, while vertical flow bioreactors are applied to remove trace metals as metal sulfides and to generate alkalinity (Watzlaf et al, 2004). To this point in time, the prominent train of thought with respect to the disposal of these waste by-products is via excavation and consequential landfilling as a controlled or special waste (Wiseman and Edwards, 2004). The disposal of these waste by-products only requires action to be taken once a treatment system reaches its designed carrying capacity of accumulated waste materials (typically 10-30 years).…”