Cause analysis for fouling mitigation, techno-economic and toxicity reduction assessments of hairwork dyeing effluent reclamation via membrane-based hybrid systems

Based on the continuous innovation of membrane materials and partnered reagents, it is necessary to timely evaluate the efficiency improvement of a package of relevant wastewater treatment processes and clarify the associated pivotal causes. For this purpose, the root-cause analysis for fouling mitigation derived from influent characteristics, the techno-economic and toxicity reduction assessments of hairwork dyeing effluent (HDE) reclamation via three membrane-based hybrid systems approaching zero discharge were systematically carried out. The experimental results showed that with the aid of a novel efficient and biodegradable flocculant, the lower fluorescence peak intensity, the more negative zeta potential and the quantitatively dominant hydrophobic components in feedwater all helped to mitigate the same-charged hydrophilic TFN-CQDs membrane fouling due to modification of itself. Accordingly, the optimal processing technology required the minimum amount and replacement frequency for membrane elements and less than 1/5 and 1/10 of the energy consumption and chemicals of their counterparts, respectively. Besides, it also decreased the waste (brine) stream volume fraction to 7%, and greatly increased B/C value of supernatant to 0.667, thus strengthening "intermediate control" of pollutants. Although the organic contaminant components in HDE basically transcend the aromatic/hydrophilic differences in producing biotoxicity, all schemes still had good performance in its elimination. Undoubtedly, the outcome of these evaluations will provide valuable technical guidance for scaling-up the prototype results and promoting the cleaner production of local wig enterprises.