Treatment of acidic metal-rich drainage from reclaimed ironstone mine spoil

Abstract

Ironstone mine spoil leaves a legacy of land contamination and diffuse water pollution with acidic, metal-rich drainage. Reclamation for woodland may exacerbate water pollution due to spoil amendment and disturbance. Constructed wetland systems (CWS) are increasingly used for treating acid mine drainage but their performance is poorly understood. A combined approach was used to reclaim the Benhar ironstone spoil heap in Central Scotland. Trees have been planted in spoil treated with dried pelleted sewage sludge, limestone and peat. Spoil drainage (pH 2.7, 247 mg l−1 total Fe) passes through a CWS. Spoil throughflow, surface water chemistry and CWS performance were monitored for 12 months after reclamation. Acidity, Fe, Mn and Al concentrations declined in throughflow after reclamation, although this effect was not uniform. Soluble reactive P has been mobilised from the sewage sludge in residual areas of spoil acidity, but losses of other nutrients were short-lived. The CWS removes on average 33 % and 20–40% of acidity and metal inputs but removal rates decrease in winter. Spoil reclamation has been successful in enabling vegetation establishment but has also increased Fe and Mn concentration in surface drainage from the site, even after passage through the CWS.

Use of constructed wetland for the removal of heavy metals from industrial wastewater

“…Treatment efficiency for removal of various HMs was determined by the retention equation, as used by Heal and Salt (1999) and Solano et al (2004).…”

Effects on the Underlying Water Column by Ecologically Engineered Floating Vegetation Mats

“…Passive AMD treatment systems, such as VFB, require strategies to limit the impact of low ambient temperatures (Heal and Salt, 1999;Johnson and Hallberg, 2002;Watzlaf et al, 2004;Champagne et al, 2005;Gusek, 2005), especially in extreme latitudes or higher elevations. The results suggest that in a colder climate, EFVM would insulate the underlying water column and substrate from the cooler temperatures that often limit the preferential biogeochemical reactions central to VFB performance.…”

The Adsorption Behavior of Cu2+Fe2+onto Waste Seaweed in Acid Mine Drainage

“…Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions Acid mine drainage (AMD) has been recognized as one of the most serious environmental problems in coal and metal-mining sites. AMD could be generated when sulfide ores undergo chemical and biological oxidation processes, and has been characterized by low pH-values and high levels of sulfate and metals (Banwart and Malmstrom, 2001;Barton and Karathanasis, 1999;Cherry et al, 2001;Christensen et al, 1996;Cravotta and Trahan, 1999;Gazea et al, 1996;Heal and Salt, 1999;Ledin and Pedersen, 1996;Robinson and Robb, 1995;Sasowsky et al, 2000). The oxidation of pyrite, which is the most abundant sulfide mineral, can be expressed by the following equations (Ritchie, 1994;Stumm and Morgan, 1981 …”