| 摘要: | 本研究選擇用水量較大之產業，包含工業區二級(KI2)/三級處理水(KI3)、化學機械研磨廢水(CMP)與染整廠放流水(TEX)，以超濾(UF)與逆滲透(RO)薄膜程序加以處理，探討水質特性與薄膜特性對兩種薄膜處理效率影響，並評估UF/RO程序回收廢水之可行性。 研究結果顯示，UF過濾四種水樣之滲透液通量探討中，由Hermia模式模擬之阻塞機制以標準阻塞與濾餅過濾兩種為主，其中微粒之粒徑與界達電位為影響滲透液通量的主要因子。水樣經過UF處理後 SDI 值有明顯的下降，KI2、KI3、CMP與TEX分別降至 6.3、6.0、6.0 與 3.3，此對RO膜操作仍可能有很高的阻塞趨勢，但經過 UF 前處理確實可維持較佳的RO滲透液通量，顯示 UF前處理仍有其必要性。此外，本研究亦以原子力顯微鏡(AFM)、掃描式電子顯微鏡(SEM)、膠體滲透層析儀(GPC)、界達電位與膜面接觸角等膜面特性與各項水質分析，推測UF與RO去除污染物之機制，UF去除懸浮微粒的機制應包含篩除與靜電排斥力，而RO對於微粒也以篩除機制加以去除；UF與RO對於有機物質的去除，皆包含有篩除機制、靜電排斥力與疏水性交互作用，而RO膜之膜孔甚小於UF薄膜，膜面亦帶有負電性，且其疏水性高於UF薄膜，所以可將有機物大量的去除；在無機鹽類方面，UF對於導電度的去除效果，應該由膜面所帶電性造成，至於RO方面，由於其屬於表面緻密薄膜，對於水中無機鹽類去除應該以溶解擴散機制為主。 另一方面，經UF/RO程序處理後，KI2與KI3之滲透液濁度、色度及導電度去除率，分別為99 %、95 % 及 96 % 以上，處理水可用於冷卻水與低壓鍋爐用水；CMP滲透液的濁度去除率可達 99 % 以上，處理水可作為超純水製水機的飼水；TEX之滲透液色度與導電度去除率，分別為96 %與95 %以上，處理水符合自來水與紡織業用水標準，僅pH值有略高之現象。此外，於回用時需考量是否會有微生物與管線腐蝕問題。最後本研究分析不同水樣之造水成本，KI2、KI3、CMP與TEX分別為 31.1、27.7、13.1與 27.4 元/噸，以工業取水現狀而言，造水成本偏高，但若基於零排放的目標與用水合理化的考量下，未來徵收水污費、調整水價及以法規規範各產業之水回收再利用率後，則UF/RO 程序回收廢水將具有潛在優勢與可行性。 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. |
