Use of microcapsules with electrostatically immobilized bacterial cells or enzyme extract to remove nonylphenol in wastewater sludge

We investigated the use of a high-voltage electrostatic system to immobilize bacterial cells or enzyme extract in alginate microcapsules for removing nonylphenol (NP) from wastewater sludge. With applied potential increased from 0 to 12 kV, the gel bead diameter decreased from 950 to 250 mu m. The amount of bacterial cells or enzyme extract immobilized in alginate microcapsules was greater than that in suspension, for improved tolerance to environmental loadings. Removal of NP at 2.0-20.0 mg L-1 was greater with extract- than cell-containing microcapsules. The percentage of toxic chemicals (2.0 mg L-1) removed with alginate microcapsules, in descending order of magnitude, was bisphenol-F > bisphenol-A > NP > oxytetracycline > chlortetracycline > tetracycline > dibromodiphenyl ethers > tetrabromobisphenol-A > decabromodiphenyl ether. (C) 2013 Elsevier Ltd. All rights reserved.