Study on the cause of membrane fouling in TFT-LCD wastewater reclamation system

• Main Authors: Yu-TzeFeng, 馮育澤
• Other Authors: Hsuan-Hsien Yeh
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/27053716842979396105

碩士 === 國立成功大學 === 環境工程學系碩博士班 === 100 === This research is focus on the membrane fouling phenomena in TFT-LCD wastewater reclamation system. Membrane process has become more and more popular in water treatment. However, the major problem of membrane process is fouling. Fouling will increase transmembrane pressure, cause flux decline and shorten membrane life. Therefore, fouling control is essential for the success of membrane process. The first step of fouling control is identification of foulant and the understanding of fouling mechanism. After know what is the foulant and fouling phenomena, the operational parameters of the process can be adjusted for the purpose of control fouling. Usually, the foulants come from source water and their properties may be changed during the pretreatment process. Therefore, in this research, firstly, the water quality characteristic of the source water and waters from various units of the treatment process train were analyzed. Secondly, autopsies of fouled membranes, both pretreatment cartridge filter and RO, were carried out to identify the foulant. Then both results were compared, and the identity and source of the foulants speculated. Based on the results from both water quality analysis and autopsy of fouled membrane, the major constituents of the foulants are considered to be organics. Further, based on the molecular characteristics of foulants, obtained from high performance size exclusion chromatography(HPSEC) and excitation/emission matrix spectofluorometer(EEM), the organic foulants were speculated to be mainly come from color filter manufacture process. The result also show that the biopolisher unit in the water treatment process may make the fouling phenomena even worse, as the low molecular weight organic were metabolized and high molecular weight soluble microbial product(SMP) released into the effluent of the biopolisher. The SMP may cause serious fouling in the following membrane units. This speculation was proved by the improvement in RO fouling control, such as lower chemical cleaning frequency and higher recovery, when the treatment process train was adjusted by deleting the biopolisher and adding activated carbon filter.