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The response of a continuous two-phase partitioning bioreactor (C-TPPB) operated with polymeric tubing treating hypersaline wastewater was investigated under dynamic load conditions of step, ramp and impulse inputs of the influent flow rate. Tests were performed with synthetic wastewater consisting of NaCl (100 g L −1 ) and 2,4-dimethylphenol (DMP) (∼1200 mg L −1 ) to simulate the organic fraction. A biomass specifically acclimatized to the compound was utilized in the tests. The experimental system provides separation of the toxic wastewater flowing inside the polymeric tubing (coiled in the bioreactor) from the microbial culture present in the bulk bioreactor phase with the polymer providing permeability to the organic molecules as well as a barrier to salt transport. These features allowed achieving high performance even in the most severe loading conditions. Removal efficiencies >96% were obtained for DMP under all investigated load conditions (i.e. for influent salt and organic loads up to six times the base case load). A DMP mass balance at the end of the dynamic tests showed that 88% of the removed DMP was biodegraded and only 8% was retained into the polymer tubing itself. No significant variation of the DMP concentration in the bioreactor was observed in all cases thus demonstrating the complete removal of the transferred substrate and the effective performance of the biomass, which was not affected by the applied dynamic loads. A comparative analysis of C-TPPB results with the performance data of the classical technologies commonly applied for saline wastewater treatment has been performed to evaluate the system applicability. [ABSTRACT FROM AUTHOR]

A continuous two-phase partitioning bioreactor has been tested for treating a synthetic leather tannery wastewater with the objective of achieving effective removal of the organic load and complete chromium separation. The bioreactor was operated with 5.5 m of Hytrel 8206 polymeric tubing fed with a synthetic tannery wastewater consisting of 4-chlorophenol (concentration in the range of 1000–2500 mg L −1 ) and potassium dichromate (100 mg L −1 as Cr (VI)), and immersed in a 4 L bioreactor containing the microbial culture acclimatized to the compound. This configuration prevents the direct contact between the toxic wastewater and the microorganisms themselves, and provides the gradual organic substrate delivery through the tubing walls. Abiotic partition and mass transfer tests were performed to investigate the transport of dichromate and 4-chlorophenol across the tubing into the bulk phase of the bioreactor. No appreciable mass transfer of dichromate was detected. During biotic testing, the influent organic load in tubing has been varied in the range of 19–94 mg h −1 and the hydraulic retention time from 3 to 6 h. Achieved biological removal efficiencies were in the range of 89–95% for the highest applied loads. Process kinetics (which included consideration of both mass transfer and biological rates) were evaluated, and it was found that the increased load did not result in any decrease in 4-chlorophenol removal rate. This work has shown that the continuous two-phase partitioning bioreactor has significant potential in enhancing the biological treatment of tannery wastewater, which is a typical representative of industrial “hostile” wastewater. [ABSTRACT FROM AUTHOR]

Effective biological treatment of high salt content wastewater requires consideration of both salt and organic toxicity. This study treated a synthetic saline wastewater containing NaCl (100 g L − 1 ) and 2,4-dimethylphenol (1.2 g L − 1 ) with a hybrid system consisting of a biological reactor containing spiral-coiled polymeric tubing through which the mixed feed was pumped. The tubing wall was permeable to the organic contaminant, but not to the salt, which allowed transfer of the organic into the cell-containing bioreactor contents for degradation, while not exposing the cells to high salt concentrations. Different grades of DuPont Hytrel polymer were examined on the basis of organic affinity predictions and experimental partition and mass transfer tests. Hytrel G3548 tubing showed the highest permeability for 2,4-dimethylphenol while exerting an effective salt barrier, and was used to verify the feasibility of the proposed system. Very high organic removal (99% after just 5 h of treatment) and effective biodegradation of the organic fraction of the wastewater (> 90% at the end of the test) were observed. Complete salt separation from the microbial culture was also achieved. [ABSTRACT FROM AUTHOR]