3 - Homogeneously distributed membrane pores - Long service life - High chemical and thermo- stability Excellence - High cost (5~10 times) - Fragile Drawback Defect in a ceramic membrane
4 Tight Ceramic UF (CTUF) & Ceramic NF (CNF) Polymeric membranes Ceramic membranes Relative size of common materials
5 Multivalent anion rejection using negatively charged CTUF or CNF A membrane pore with negative surface charge Electrostatic repulsion Double layer overlap Cations >> anions Take-home message: 40%~87% of Ortho-P rejection by a 3 kDa TCUF, dependent on operational conditions (flux, cross-flow velocity, pH). Higher solution pH leads to higher rejection, due to enhanced negative surface charge. (Shang et al. Wat. Res. V. 48 P. 498-507)
6 Secondary effluent water filtration using 3kDa TCUF Rejections, % Organic matter 45±3 in DOC 61±2 in UV 254 Phosphate62±7 Sulphate16±1 Nitrate1.0±0.5 Conductivity4.1±0.1 Take-home message: Phosphate has negative charge and low diffusion: thus easy removal. Membrane fouling by effluent organic matter can enhance phosphate rejection. About 50% or higher organic removal.
7 Implication(1) for effluent water reuse PS Municipal wastewater AS SS MMFUFRO Demiwater for reuse Digester Coag.TCUF /CNF RO Demiwater for reuse >95% P removal ~40% OC removal ~60% P removal ~50% OC removal ~0,3 µg P L -1 ~3 mg L -1 TOC P limitation!! Low organic carbon!!
8 Implication(2) for sewer mining PS Municipal wastewater AS SS MMFUFRO Demiwater for reuse Digester CNF RO Demiwater for reuse Digester Energy Struvite P limitation Anaerobic RO Municipal wastewater PS