Operating efficiency and membrane fouling characteristics of high efficiency reverse osmosis process in coal chemical wastewater treatment
The concentration and reduction of concentrated brine by high efficiency reverse osmosis(HERO)process is the key for the zero liquid discharge wastewater system.Its operation effect significantly affects the efficiency of the following evaporation and crystallization,and directly determined the stability and cost of the system operation.In this study,the operation effect and membrane fouling characteristics of a HERO process for the zero liquid discharge coal chemical wastewater treatment system in North China was analyzed to disclose the key issue in HERO.Calcium and magnesium can be efficiently removed in the clarifying ponds and cation exchange system,while other ions and pollutants are mainly removed in RO.The dissolved organic matters are mainly microbial sourced humic substance and soluble microbial products,and humic substance is the main microbal source.The pretreatment stage has not targeted measure for SiO2 control,and the removal efficiency of silica(SiO2)is poor(29.43％)for coagulation,thus the concentration is high in the HERO process,resulting in severe silica combined fouling.The silica-organics,microorganisms and their metabolites are the main foulants in the 1st-stage RO,while silica scaling appear in the 2nd-stage RO due to the high concentration factor.Therefore,further strengthening SiO2 removal and its cleaning efficiency during chemical cleaning are key measures to alleviate membrane fouling and improve the operation stability.
coal chemical wastewaterhigh efficiency reverse osmosismembrane foulingdissolved organic matterSilica
国家科技期刊平台
NSTL
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