Biodegradation of purified terephthalic acid manufacturing effluent from a petrochemical industry

摘要

Purified terephthalic acid (PTA) is the raw material for polyester fibres, plastics, coating and adhesives. Its manufacture generates large volumes of effluent with high concentration of terephthalic acid (500-600 ppm), a critical pollutant. In this study a mixed culture made up of five types of bacteria, derived from the effluent treatment plant (ETP) sludge was used to aerobically treat the PTA effluent, removing all the benzoates [4-carboxybenzyl alcohol, isophthalic acid, terephthalic acid, 4-carboxy benzaldehyde (4-CBA), benzoic acid, p-toluic acid and trimellitic acid] which contribute to its chemical oxygen demand (COD). The study included optimisation of pH (6-9), pH neutralisers and biomass concentration (≥2,000 ppm Mixed liquor suspended solids) for achieving 94–95% COD removal in 72–96 h, the results being supported by HPLC analysis. Metals (Co, Mn and Mg) reduced significantly (88%, ~100% and 83%, respectively), being utilised for growth or getting sequestered in the biomass. Characterisation of the five pure cultures was carried out.