Plant effects on microbial assemblages and remediation of acidic coal pile runoff in mesocosm treatment wetlands

摘要

Constructed treatment mesocosm wetland systems comprised of an anaerobic wetland followed by two aerobic wetlands and differing in aerobic wetland composition (real plants,plastic plants,no plants) and order (shallow aerobic wetland followed by deep aerobic wetland or vice versa) were compared to determine if composition or order affect remediation of acidic,metal contaminated water associated with a coal-fired power plant.Aerobic cell composition was varied to determine if native plants have no function,are only structure for bacteria,or improve water quality.The anaerobic cells increased pH from 2.4 to 6.4 and reduced Al,Fe,and Zn by 93-99%.Order of the aerobic cells did not affect water quality.Cells with real versus plastic plants had different bacterial assemblages,but these were not clearly related to water quality differences between the tank types.Cells with real plants had lower pH and NH_4 and higher Fe and Mn,especially during the growing season,than those with plastic plants or without plants.We conclude that plants do affect water quality,in part because they affect bacterial assemblages.Planted aerobic wetlands can help remediate acidic,metal-contaminated water,but may contribute to lower pH and greater Fe and Mn concentrations in treatment effluent.Published by Elsevier B.V.