Alkalinity Generation in a Novel Multi-stage High-strength Acid Mine Drainage and Municipal Wastewater Passive Co-treatment System

Abstract

Passive co-treatment of high-strength acid mine drainage (AMD) and municipal wastewater (MWW) was examined in a laboratory-scale, four-stage continuous flow reactor system with a total residence time of 6.6 d. Synthetic AMD of pH 2.60 and an acidity of 1,870 mg/L (as CaCO 3 ) was mixed at a 1:2 ratio with raw MWW (pH 7.67, 288 mg/L alkalinity (as CaCO 3 ), and 265 mg/L BOD 5 ) from the City of Norman, Oklahoma and introduced into the system. Alkalinity generated by limestone dissolution and bacterial SO 4 2-reduction (BSR) processes was sufficient to support various metal removal processes and produce an effluent with circumneutral pH (6.98) and a net alkalinity of 10.4 mg/L (as CaCO 3 ). Alkalinity generation from limestone dissolution was comparable with conventional AMD passive treatment systems. BSR proceeded at a relatively high rate (0.56 mol/m 3 day) despite inhibitory pH and metals concentrations. Results indicate that the diverse electron donors in the MWW may be as suitable for BSR and their supporting microbial communities as commonly used substrates, presenting an opportunity to use a common waste as a resource for passive treatment.

Heterotrophic Microbial Stimulation through Biosolids Addition for Enhanced Acid Mine Drainage Control

“…Techniques like the co-treatment of municipal wastewater (with biosolids as byproducts) and AMD has recently gained popularity following its introduction by Roetman [39], when it was proposed to remove pathogens in sewage [40]. Results from studies to date have shown the removal of metals, certain nutrients, increases in pH and alkalinity, and overall water/leachates quality improvements [41][42][43][44][45][46][47][48][49][50].…”

Technical note The formulation of synthetic domestic wastewater sludge medium to study anaerobic biological treatment of acid mine drainage in the laboratory

“…Therefore the challenge is to find a suitable inexpensive and sustainable carbon source for adequate reduction of sulphates (Santamaria et al, 2014). The co-treatment of AMD and municipal wastewater has become a treatment option of interest as the simultaneous treatment of municipal wastewater and AMD allows a reduction in treatment costs (Strosnider et al, 2011a;Strosnider et al, 2011b;Strosnider et al, 2013). A 1:1 ratio of AMD and sewage also showed a significant decrease in acidity, organic matter, nutrients, iron and manganese concentrations, and complete removal of pathogens (Neto et al, 2010).…”

Evaluating sulphate removal and identifying the bacterial community present in acid mine drainage treated with synthetic domestic wastewater sludge

“…Domestic wastewater has a significant environmental impact due to its insufficient treatment in developing countries (Gadgil, 1998;Strosnider et al, 2011a). The passive co-treatment of AMD and domestic wastewater can meet the requirements of both treatment processes as the effluent of each consists of elements that can be used by the other (Strosnider et al, 2011b). Domestic wastewater is readily available and is therefore a convenient and cost-effective carbon source for potential treatment of AMD (Gadgil, 1998;Strosnider et al, 2011a).…”

“…The presence of biofilms has been described at AMD sites (Denef et al, 2011;Smucker and Vis, 2011) and may therefore play a potential role in AMD treatment. Domestic wastewater has a significant environmental impact due to its insufficient treatment in developing countries (Gadgil, 1998;Strosnider et al, 2011a). The passive co-treatment of AMD and domestic wastewater can meet the requirements of both treatment processes as the effluent of each consists of elements that can be used by the other (Strosnider et al, 2011b).…”

“…Although the use of alkaline chemicals or limestone (Nairn et al, 1992) in the abiotic treatment of AMD is convenient, it is not environmentally friendly due to the formation of bulky sludge (Johnson and Hallberg, 2005). Passive biotic remediation methods rely on the use of microbial treatment systems by the once-off addition of one carbon source, such as domestic wastewater (Davison et al, 1989;Strosnider et al, 2011a and2011b). This creates conditions that will select for specific microbial populations responsible for the removal of sulphates, organic matter content and heavy metals, as well as neutralize the pH of the AMD (Barton and Fauque, 2009).…”