Recovery and Microbial Remediation of Organic Wood Preservatives in Groundwater at a Former Wood Treating Plant

Abstract

Well‐recovery networks coupled to immobilized microbe bioreactors (IMBRs) were installed at a 172‐acre former wood preserving facility for the bioremediation of organic wood preservatives present in site groundwater. Free‐phase creosote from the hardpan and soluble preservative fractions contained in subsurface groundwater were pumped separately to different holding tanks. Trace creosote fractions contained in the subsurface groundwater were further gravity separated in the holding tank. Immobilized microbial isolates evaluated in earlier laboratory and field pilot tests were established into two 40, 000‐liter bioreactors for the biodegradation of all targeted consitituents. Microbial growth, dissolved oxygen, pH, nutrients, flow rate, and temperature were monitored in this in situ/ex situ bioremediation system. The process was used to remove the polycyclic aromatic hydrocarbon (PAH) and phenolic components of creosote and pentachlorophenol from contaminated groundwater. Data generated during the past 2 1/2 years indicate that 26 target compounds consistently are reduced to levels acceptable for discharge. Currently operating in Baldwin, Florida, this full‐scale prototype is remediating the former wood preserving facility and is being used as a model system for the design and construction of new bioreactor systems needed at similar industrial sites in the United States and abroad.

Managing bioremediation of a creosote‐contaminated superfund site by optimizing moisture and temperature in a biopile

“…Immobilized microbe bioreactors (IMBRs) have been shown to be a successful bioremediation technology for cleanup of contaminated Superfund sites (Portier, 1994;Portier et al, 1998). Details of this technology are available elsewhere (Portier et al, 1990).…”

“…A preferred microbial consortia with identified capabilities for biodegradation/mineralization is permanently attached to this porous matrix so as to optimally seed contaminated soils from a permanent point source. The IMBR system optimizes conditions necessary for microbial growth and provides the necessary oxygen and nutrients for rapid mineralization of selected waste streams (Portier et al, 1998).A bioplug is a miniaturized adaptation of IMBR technology and is usually made of a slotted polyvinyl chloride (PVC) or high-density polyethylene (HDPE) pipe packed with the previously described inoculated beads (Exhibit 1). metabolic specificity toward the compounds of concern at the remediation location (Portier et al, 1990).…”