title: Use of calcium peroxide to provide oxygen for contaminant biodegradation in a saturated soil.
abstract: Laboratory studies were conducted in solid-phase reactors on a silty loam contaminated with bis-(2-ethylhexyl) phthalate (BEHP) to determine the conditions under which calcium peroxide (CaO(2)) would promote the aerobic bioremediation of water-saturated soil. Closed 500 ml solid-phase reactors were operated to determine whether CaO(2) stimulated the biodegradation of BEHP in saturated soil. Ex situ bioremediation conditions were then simulated by mixing water-saturated soil for 6 h before placing the soil in three vented, 2 l solid-phase reactors for 50 days. Biodegradation of BEHP was quantified using four different measurements of microbial activity: (1) oxygen concentrations in the reactor gas; (2) bacterial colony-forming units (CFU); (3) fungal CFU; and (4) 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride dehydrogenase activity (INT-DHA). CaO(2) released molecular O(2), which retarded dewatering but substantially enhanced BEHP biodegradation. After 20 days, BEHP in the amended reactor was reduced from 20.3 to roughly 5 g kg(-1) vs. 15 g kg(-1) in the reactor without CaO(2). Bacterial growth was favored over fungal growth at elevated moisture and BEHP levels.
authors.affiliation: Department of Geosciences, Western Michigan University, Kalamazoo, MI 49008, USA. daniel.cassidy@wmich.edu
authors.forename: D P
authors.initials: DP
authors.lastname: Cassidy
authors.forename: R L
authors.initials: RL
authors.lastname: Irvine
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D017610:Calcium Compounds / Q000737:chemistry; D004787:Environmental Pollution / Q000517:prevention & control; D005658:Fungi / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D010545:Peroxides / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D017610:Calcium Compounds; D010545:Peroxides; D012989:Soil Pollutants; D010100:Oxygen