Bioremediation of soils contaminated with bis‐(2‐ethylhexyl) phthalate (BEHP)in a soil slurry‐sequencing batch reactor

Abstract

A bench-scde study was conducted to assess the feasibility of bioremediating phthalate contaminated soil from a polyvinyl chloride manufacturing operation in New Jersey. 14 bench-scale slurry reactor study which utilized I4C-labeled bis- (2-ethylhexyl) INTRODUCTIONPeriodic flooding of a separator pit at a northern New Jersey manufacturing site engaged in polyvinyl chloride (PVC) compounding and garden hose and PVC pellet manufacturing caused bis-(2-ethylhexyl) phthalate (BEHP, also known as di-(2-ethylhexyl) phthalate or DEHP) to be spread over the ground surface and contaminate the soils. Analysis of soil samples at the site for baselneutral extractable fractions (baselneutrals) and total petroleum hydroca.rbons (TPH) indicated the presence of phthalates (specifically BEHP) in the range of 10 to 25,000 mg/kg and TPH in the range of 10 to 2,000 mg/kg. The estimated volume of contaminated soil to be remediated was approximately 2,300 cubic meters. Groundwater testing for volatile organics, base/neutrals, and petroleum hydrocarbons show only limited contamination with no volatiles and low levels of BEHP and TPH present. There was no evidence of PCB or pesticide contamination at the site. A preliminary cost analysis suggested that on-site bioremediation in slurry reactors would be 1.5 to 2 times more cost effective than excavation and that the cost for incineration would be prohibitive. The study described herein was conducted because of concerns raised by the regulatory agency that BEHP was nonbiodegradable in soils contaminated with both BEHP and TPH and because data were needed to prepare a preliminary design for the periodically operated Soil SlurrySequencing Batch Reactor (SS-SBR) system. Results obtained from a literature review suggested that BEHP may be recalcitrant under anaerobic conditions but that it was biologically degradable in aerobic systems [I, 2 , 3 , 4, 51. While the results from the aerobic studies strongly suggested that a microbial consortium capable of degrading BEHP would develop in soil slurry reactors, no direct evidence was found in the literature.

Biological breakdown of RDX in slurry reactors proceeds with multiple kinetically distinguishable paths

“…Of particular interest in this study is biotransformation of RDX in slurry reactors. A number of researchers have used soil slurry reactors to degrade hazardous compounds, such as phenol (Vipulananden et al, 1995), chlorophenol (Kiilerich et al, 1993), naphthalenes (Al-Bashir et al, 1994), chlorinated benzenes (Brunsbach and Reineke, 1994;Ramanand et al, 1993), chlorinated toluenes (Ramanand et al, 1993), chlorobenzoates (Brunsbach and Reineke, 1993a), bis-(2-ethylhexyl) phthalate (Irvine et al, 1993), chloroanilines (Brunsbach and Reineke, 1993b), atrazine (Rouchaud et al, 1994), and lubricating oil (Rittmann and Johnson, 1989). Numerical analysis of the rates of degradation in these slurry reactors was not normally performed; the major focus was demon-strating that degradation occurred over a designated time frame.…”

Biotreatment of Flare Pit Waste

“…(5) Slurry reactor studies have been used to evaluate the treatability of creosote contaminated soil (6) , BTEX and PAH contaminated soil (4) , crude oil and refined petroleum products (7) and oil-contaminated sandy soil (8) . For example, Irvine et al (9) demonstrated the successful use of a soil-slurry batch reactor for biotreatment of soils contaminated with petroleum hydrocarbons. They observed total petroleum hydrocarbon (TPH) removal efficiencies greater than 96% in slurry reactors supplemented with nutrients.…”

Activated sludge and other aerobic suspended culture processes

“…Biological treatment of wastewater containing phenol and o-cresol was achieved using an SBR operated with a I-day hydraulic residence time and a 14-day SRT . Greater than 99.5% removal of both compounds was achieved at phenol loading rates of 0.1 to 0.8 kg/m 3. d, and o-cresolloading rates of 0.1 to 0.6 kg/rn 3. d. Bench-scale slurry phase SBRs were used to treat soil contaminated with up to 24000 rug/kg bis-(2-ethylhexyl )phthalate (BEHP) (Irvine et al, 1993). Greater than 96% removal of BEHP was achieved in reactors supplemented with nutrients.…”