Manganese and Iron Removal from Coal Mine Drainage by Use of a Green Algae-Microbial Mat Consortium

Abstract

At the Tennessee Valley Authority's Fabius Coal Mine, Alabama, manganese was more effectively removed from a pond containing an algae mat consortium and limestone substrate than from ponds containing only limestone or pea gravel substrates. The algae mat resulted from the integration of a microbial mat and volunteer filamentous green algae. The microbial mat consisted of blue-green algae (predominately Oscillatoria spp.) and bacteria isolated from the site, cultured in the laboratmy, and returned to the site. System operation ran from August 1992 through March 1993. Manganese and iron were consistently removed more efficiently in the algae mat pond (mean flow of 4.2 L/min) than through gravel-only ponds even as water temperatures dropped to less than 5° C in the winter.. Based on filtered water samples, during winter months, at 2 m from the influent point of each pond, the algae mat pond removed 2.59 g/d/m' manganese, compared with 0.80 in the limestone pond and 0.37 in the pea gravel pond. At 1 m from the influent pipe in the algae mat pond, 2.67 mg manganese and 34.25 mg iron were deposited in a gram of dried mat. In March 1993 two events likely caused the loss of much of the algae mat: (1) a 50-cm snowfall followed by a heavy runoff and (2) establishment of a snail population, as well as other possible invertebrate herbivores, which consumed the algae mat. The algae mat was reestablished in June 1993 and has persisted to date. A green algae and microbial mat consortium may be a cost-effective treatment technique for permanently removing metals from mine drainage.

Treatment of Mine Water by a Microbial Mat: Bench-scale Experiments

“…Phillips et al (1994) conducted similar experiments in AMD from coalmines and obtained similar results. For a developing country like India, passive treatment systems, which have no energy requirements, are preferred.…”

“…Mats have been reported to reduce Pb, Cd, Cu, Zn, Co, Cr, Fe, and Mn. Mats are nitrogen fixing and photosynthetic (Phillips et al 1994), and so are selfsufficient solar-driven ecosystems with few growth requirements. Mats have been found to reduce selenate to elemental selenium (Bender et al 1991) Degradation of recalcitrant organic contaminants has also been observed under both dark and light conditions.…”

Performance of Three Aquatic Plant Species in Bench-scale Acid Mine Drainage Wetland Test Cells

“…Phytoplanktons have also been reported to be quite efficient in heavy metal removal from AMD (Bender et al 1989(Bender et al , 1991Phillips et al 1994;Sheoran and Bhandari 2005). Kalin et al (2004) reported that algae like Chara nitella provide a simple, long term means to remove uranium and other radionuclides from uranium mining effluents.…”

Soil and Water Pollution Monitoring, Protection and Remediation

“…Active systems involve technologies such as pH modification, ion exchange, biology-based treatments, adsorption, electrochemical treatment and physical process technologies. Passive treatment includes chemical passive treatment by the addition of chemicals such as limestone, polymers or others (Braun et al, 2001;Brodie et al, 1993;Ziemkiewicz et al, 1997) and biological passive treatment represented by primary constructed wetlands and secondary algal systems or special bioreactors (Braun et al, 2001;Foster, 1982;Phillips et al, 1994;Davison, 1993;Duc et al, 1998). The passive treatment systems, and in particular constructed wetlands, are advantageous mainly because they cause comparably low costs, are truly self-sustaining and are suitable for the treatment of mine water from abandoned mines (Braun et al, 2001).…”