A continuous two-phase bioreactor for effective decontamination of industrial wastewater and valuable component recovery.

Environmental concerns derived by tannery industry promoted research activities aimed at developing alternative methods in tanning process for a cleaner production and new strategies for enhancing wastewater treatment. Biological treatment of effluents produced by this manufacturing sector is challenging due to strong inhibition exerted by their constituents on the microbial communities. A continuous two-phase partitioning bioreactor (C-TPPB) has been tested for treating a synthetic leather tannery wastewater (consisting of 4-chlorophenol (4CP) and potassium dichromate as source of chromium) with the objective of achieving the effective removal of the organic load and complete chromium separation for subsequent recovery. No appreciable dichromate transfer was observed through the tubing walls, while gradual mass transfer of 4CP took place from the tubing to the bioreactor bulk phase. Therefore, toxic dichromate was not in contact with the cells while the transferred 4CP was effectively biodegraded. During biological testing, the influent organic concentration has been varied in the range of 1000-2500 mg L-1, while the chromium was fed at 100 mg L-1. The system achieved biological 4CP removal efficiencies of ~ 90% for the highest applied organic loads.