Treatment of wastewater containing high phenol concentrations using stabilisation ponds enriched with activated sludge

Abstract

Treatment of wastewater containing high phenol concentrations (up to 4,000 mg/l, 1,600 kg/ha.d) in laboratory-scale stabilisation ponds enriched with activated sludge was studied. Phenol was biodegraded efficiently, even when fed as the sole carbon source. At influent concentrations of 1,000, 1,300, 1,600, 1,900, 2,500, 3,000 and 4,000 mg/l of phenol (loading rates of 400, 520, 640, 760, 1,000, 1,200 and 1,600 kg phenol/ha.d), the phenol removal efficiencies were 92, 89, 81, 81, 76, 65 and 22%, respectively. At 4,000 mg/l of phenol, the enriched ponds were significantly inhibited. The maximum phenol removal rate observed was 780 kg/ha.d, which is 7.7 times higher than the maximum value reported for attached-growth waste stabilisation ponds. All along the experiments, the enriched ponds showed removal rates 1.8-20.5 times higher than the values observed in control pond (not enriched). The results suggest that enrichment is an effective method to increase xenobiotic removal rates of stabilisation ponds.

Survey on Treatment Ability of Stabilization Pond as a Natural Treatment System in Oil Refinery Wastewaters

“…In a study undertaken by Ramos et al using the laboratory scale facultative stabilization pond in which wastewaters with high phenol content was used for removal of phenol with different concentrations, the results showed that the highest and lowest rates of phenol removal relates to 1,000 mg/L (92%) and 4,000 mg/L (22%) concentrations, respectively [28]; but for the anaerobic pond for phenol removal no independent study was found. Results of the study by Nahid et al showed that by the increase in concentrating phenol within the range 0-200 mg/L, the COD removal rate is reduced due to the phenol toxicity effect on the microbial mass activity [29].…”