Treatability Study for Hill AFB's Operable Unit-1: Enhanced Microaerobic Dechlorination Using Various Electron Donors

摘要

A treatability study of the microaerobic biodegradation of cis- dichloroethene (c-DCE) was completed using a series of eight continuously operated columns filled with contaminated soils from Hill Air Force Base's Operable Unit 1. Columns were supplied groundwater from the site, vitamins and yeast, and an electron donor solution containing one of the following donors: n- butyric acid, benzoic acid, lactic acid, propionic acid, n-propanol, or toluene. Concentrations of c-DCE varied over six months and ranged from 2736 micrograms/L to 30 micrograms/L. Though attempted as an anaerobic study, the ability to continuously eliminate oxygen from an active system proved difficult and columns operated as microaerobic systems. In all columns the degradation of c-DCE was observed, however, the removal efficiencies determined by comparing the influent and effluent concentrations were highly inconsistent throughout the experiment. By comparing the background columns to the columns supplied electron donors, it does not appear the addition of vitamins or electron donors enhance the indigenous microorganism's ability to remove c-DCE. While c-DCE removal within the background column averaged 17%, the vitamin amended control column averaged only 7% c-DCE removal within the column and the electron donor supplied columns averaged between 7% removal and 5% apparent production. Of the electron donors supporting c-DCE removal, benzoic acid demonstrated 7% removal followed closely by propionic acid and n-propanol, both showing 5% c-DCE removal.