Application of an ultra-thin fixed-bed adsorber process for advanced drinking water treatment

The ubiquitous presence of dissolved organic matter (DOM) in drinking water sources poses significant risks to water safety. Conventional treatment processes exhibit limited DOM removal efficiency, whereas traditional powdered activated carbon (PAC) dosing is hindered by low capacity utilization and subsequent separation challenges. To address these limitations, this study engineered an ultra-thin fixed-bed adsorber (UTFBA) using fine PAC. We initially evaluated the adsorption isotherms and kinetics of activated carbons across varying particle dimensions to strictly elucidate the distinct impacts of particle size on both mass transfer rates and equilibrium adsorption capacities. Reducing PAC particle size to 20.70 μm enhanced kinetics, 50% DOM removal was 60% faster than with conventional PAC. Saturated adsorption capacity varied less than 4%. At 0.06 mm bed thickness, UTFBA reached 202.81 mg·g −1 adsorption capacity at breakthrough, cutting carbon consumption by 61% vs. conventional PAC dosing. While the direct treatment of raw surface water led to membrane fouling due to the formation of a dense cake layer, the integration of coagulation pretreatment mitigated this issue. The combined coagulation-UTFBA process operated stably for over 4 h, achieving an effluent turbidity of <0.25 NTU, total organic carbon (TOC) removal efficiency of >65%, and trichloromethane formation potential of <33.43 μg·L −1 . Achieving equivalent effluent quality, the combined process reduced the required activated carbon dosage by 50% relative to conventional treatment. This work presents a mechanistically elucidated and engineerable paradigm for advanced drinking water purification.