| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 93 === The purpose of this research is to evaluate the performance relationship between wastewater chemistry and membrane properties using UF and RO membrane process to treat four types of heavily water-consuming industrial wastewaters, containing Industrial Park Secondary discharge/ Tertiary effluent (KI2/KI3), chemical mechanical polishing wastewater (CMP) and textile effluent (TEX). Simultaneously, the feasibility of water reuse treated by UF/RO membrane process was also accessed.
The result shows that the major blocking mechanism of UF membrane process simulating by Hermia model is standard blocking and cake filtration. The variation of permeate flux was effected by the particle size and zeta potential of suspended colloid materials. Although the SDI value of permeate from four types of industrial wastewater treated by UF process was significantly decreased to 6.3, 6.0, 6.0 and 3.3, respectively, it also had a high fouling potential for the feed water into RO process. On the other hand, the UF pretreatment process was also needed to increase the optimum RO permeate flux. In addition, this research utilized the innovative analytical technologies, such as AFM, SEM, contact angle, zeta potential of membrane properties, and the analysis of wastewater chemistry to elucidate the pollutant removal mechanism of UF and RO membrane process. For the rejection of suspended colloid materials, the size exclusion and electrostatic repulsion for UF process and the size exclusion for RO process are the major mechanism. For the rejection of organic substance, the size exclusion, electrostatic repulsion and hydrophobic interaction are the major mechanism for UF and RO process. Moreover, there are a lot of tinier membrane pore and higher hydrophobic on RO membrane surface resulting in the removal of organic substance on RO process was more than UF process. As far as the rejection of salt, the electrostatic repulsion for UF process and the solution and diffusion within nonporous denser membrane for RO process are the major mechanism.
On the other hand, the water quality of the reuse of permeate for four types of industrial wastewater treated by UF/RO process was also evaluated. The turbidity, color and conductivity removal efficiencies of KI2 and KI3 permeate are more than 99%, 95%, and 96%, respectively, this permeate can utilize to the reuse of cooling water and low-pressure boiler make-up water. For CMP permeate, the removal efficiency of turbidity is more than 99% and the permeate can reuse to the feed of pure water machine. For TEX permeate, the removal efficiency of color and conductivity are more than 96% and 95%, respectively, and the permeate can reuse to textile process water and tap water. In order to find the potential of application and feasibility of UF/RO process, this investigation try to analysis the treatment cost of four types of industrial wastewaters. The cost for KI2, KI3, CMP and TEX are 31.1, 27.7, 13.1 and 27.4 NT/ton, respectively.
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