Effects of micro-flocculation pretreatment on the ultrafiltration membrane fouling caused by different dissolved organic matters in treated wastewater

This study investigated the efficacy of using micro-flocculation as a pretreatment approach in alleviating ultrafiltration (UF) membrane fouling caused by organic matters in treated wastewater. Three typical model dissolved organic matters (DOM), humic acid, fulvic acid, and sodium alginate, were employed to simulate membrane fouling. The results showed that micro-flocculation using poly aluminum chloride (PAC) or polymerized ferric sulfate (PFS) as flocculant could effectively enhance the treatment performance of UF process on DOM. With 6 mg/L PAC, the removal efficiency of humic acid, fulvic acid, and sodium alginate by micro-flocculation combined UF process reached 79.95%, 63.25%, and 51.14%, respectively. Specifically, after micro-flocculation, micromolecular hydrophilic organic matter (e.g., fulvic acid) tended to form a compact cake layer. The macromolecular hydrophobic organic matter (e.g., humic acid) and macromolecular hydrophilic organic matter (e.g., sodium alginate) generally led to a loose cake layer. At PAC dosage of 6 mg/L, the membrane specific flux (J/J0) at the end was improved by 11.71%, 10.27%, and 2.2% for humic acid, sodium alginate and fulvic acid solutions, respectively, compared with UF process alone. It could be inferred that micro-flocculation pretreatment can effectively mitigate the membrane fouling when treating wastewater containing humic acid, sodium alginate, or fulvic acid.

QUESTIONS ON OPTIMUM DEVELOPMENT OF COMPLEX FOR MULTI-POINT CONTROL AND EVALUATION OF CONTAMINATION OF WATER BASINS POLLUTED BY WASTE WATER OF MINING AND PROCESSING PLANTS

The paper is devoted to questions on optimum development of complex for control and evaluation of contamination of water basins used for collection of industrial waste water. The purpose of the paper is development of scientific-methodical basics for development of measuring system for control and evaluation of contamination of natural water basins with heavy metals using method of attenuation of irradiation of dissolved organic matters excited by external irradiation. The task on optimization of operational regime of measuring complex for control and evaluation of contamination of natural water basins by waste water of large scale point type polluter of environment with heavy metals. The known model of Shtern-Volmer is used as a basis which assumes non-linear relationship between formed complex and fluorescent irradiations attenuation degree. It is noted that potential possibilities of Shtern-Volmers model are used not fully till now. So that in known researches the water objects polluted by several same sources are mainly researched. It is shown that Shtern-Volmer model is also applicable for analysis and estimation of pollution of water basins by single strong polluter that is mining and processing plants. For analysis the suggested special parameter, inversely proportional to concentration of heavy metals in water is used. Integration of this parameter on all possible values of heavy metals concentration and imposition of special limitation condition on the searched for function of dependence of attenuated part of fluorescent irradiation on maximum concentration of heavy metals make it possible to formulate and solve the task on searching of optimum type of this function providing for the optimum regime of operation of the complex.