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Pentachlorophenol reductive dechlorination in an interceptor trench: Temperature effects

Journal Article · · Ground Water
;  [1];  [2]
  1. Oregon State Univ., Corvallis, OR (United States). Dept. of Civil Engineering
  2. Richard Catlin and Associates, Inc., Stone Mountain, GA (United States)

This paper describes the development of a third remediation strategy, an interceptor trench, and laboratory studies evaluating its application to a pentachlorophenol-contaminated ground water. The interceptor trench is a sophisticated inground chemical and biological reactor equipped with chemical sensors and nutrient or chemical delivery systems. Pentachlorophenol-acclimated methanogenic consortia were incubated at temperatures of 5, 10, 21, and 31 C in physical models of an interceptor trench. Four identical 5.4 cm diameter brass columns packed with a uniform pea gravel were operated with a 2 day hydraulic retention time in a continuous upflow mode. The columns were fed 25 or 50 mg of acetate per liter, 0.32 or 4.0 {micro}M pentachlorophenol, and a dilute vitamin and nutrient mixture. In the columns operated at 31 and 21 C, pentachlorophenol was reductively dechlorinated at the ortho positions to form 2,3,4,5-tetrachlorophenol and 3,4,5-trichlorophenol. 3,4,5-trichlorophenol was the sole degradation product observed in the effluent. The lag period prior to pentachlorophenol biotransformation increased with decreasing temperature. At 31 C, a lag of 72 hours was observed; at 21 C the lag was 120 hours; and at 10 C the lag was 744 hours. No biodegradation of pentachlorophenol was observed at 5 C within an 888 hour period. Conversion of pentachlorophenol to 3,4,5-trichlorophenol was complete within the first 7.6 cm of the column at 31 and 21 C. Loss of 90% of the pentachlorophenol was observed over the 30 cm column at 10 C. An interceptor trench inoculated with a temperature- and pentachlorophenol-acclimated methanogenic consortia has the potential to anaerobically biotransform pentachlorophenol at temperatures as low as 10 C.

Sponsoring Organization:
USDOE
OSTI ID:
395086
Journal Information:
Ground Water, Journal Name: Ground Water Journal Issue: 5 Vol. 34; ISSN GRWAAP; ISSN 0017-467X
Country of Publication:
United States
Language:
English