Treatment of phenol in synthetic saline wastewater by solvent extraction and two-phase membrane biodegradation

Abstract

Phenol in synthetic saline (100 g L −1 NaCl) and acidic (pH 3) wastewater was treated by a hybrid solvent extraction and two-phase membrane biodegradation process at 30 °C. Kerosene was adopted to be the organic solvent because it was biocompatible and had a suitable partition coefficient for phenol. Phenol in water was first extracted by kerosene in a batch stirred vessel and the loaded solvent was passed through the lumen of a polyvinylidene fluoride (PVDF) hollow-fiber membrane contactor; in the meantime, Pseudomonas putida BCRC 14365 in mineral salt medium was flowed across the shell, to which tetrasodium phyophosphate (1 g L −1) was added as a dispersing agent. The effect of the initial phenol level in wastewater (110–2400 mg L −1) on phenol removal and cell growth was experimentally studied. At a cell concentration of 0.023 g L −1, it was shown that the removal of phenol from saline wastewater was more efficient at a level of 2000 mg L −1 when 0.02-m 2 membrane module was used. The effects of bigger membrane module size (0.19 m 2 area) and higher initial cell concentration (0.092–0.23 g L −1) on the performance of such a hybrid process for the treatment of higher-level phenol in saline wastewater was also evaluated and discussed.