Evaluation of anaerobic treatment of selected petrochemical wastes

Abstract

Anaerobic toxicity assays and biochemical methane potential studies were performed on three waste streams (acrylic acid, ethylene oxide and total wastes) from a petrochemical facility. The acrylic waste contained high concentrations (> 350 mg l −1) of acetic acid, acrylic acid, formaldehyde and benzaldehyde and low concentrations (< 100 mg l −1) of allyl alcohol and acrolein. The oxide waste contained high concentrations (> 950 mg l −1) of ethylene glycol, formaldehyde and acetaldehyde and low concentrations (< 50 mg l −1) of other compounds. The total waste was the combination of all waste streams generated at the plant. Unacclimated anaerobic glucose-acetate enrichment culture and a culture acclimated to the acrylic waste were used. The oxide waste with total organic carbon (TOC) concentrations of about 1400 mg l −1 was found to be readily degradable even without an acclimation period. The total waste showed no inhibition to the unacclimated glucose-acetate culture at a TOC concentration of about 250 mg l −1; however, the culture was inhibited at a TOC concentration of about 450 mg l −1. The acrylic waste caused inhibition at a TOC concentration of 269 mg l −1 in the unacclimated culture. An acclimated culture degraded a TOC concentration of 223 mg l −1 of the acrylic acid stream but was inhibited by a concentration of 643 mg l −1. A reduced acrylic waste load with a significant portion of the acetic acid removed was degradable at a TOC concentration of 138 mg l −1.