Pre-Filter Regulation Strategies and Deactivation Mechanisms of Filter Media in Water Treatment

In the context of micro-polluted water sources, the performance decline of filtration units is a major challenge for the operational management of water supply plants. Therefore, it is necessary to systematically analyze the mechanism underlying the decline in filter media activity and optimize the pre-filtration treatment. This study focuses on waterworks, aiming to enhance filtration performance through filter media modification and a combined coagulant-oxidant strategy. A key innovation of this work is the development of a macro-microscopic correlation evaluation system. The results showed that the modified filter media increased the turbidity removal rate by 10.48% compared to the unmodified media. Furthermore, the combined coagulation–pre-oxidation scheme increased the removal rates for turbidity and UV254 by 3.24% and 19.03%, respectively, compared to the single-process scheme. Combined with filter media characterization results, the deactivation mechanism of filter media can be inferred. During the high-algae period, microorganisms on the filter media generate anaerobic Extracellular Polymeric Substances (EPS), which form a biofilm with bacteria and adhere to the filter media. The viscous matrix of these EPS then encapsulates inorganic substances, resulting in hard-to-remove clumps. These clumps clog pores and hinder the adsorption of subsequent pollutants, ultimately leading to continuous deterioration in filter media performance until failure.