操作參數對純水品質及其系統穩定性的影響

Abstract

純水(Purified water)應用於製藥、食品等產業甚廣，其純水系統建置及驗證運行需要多數設備及儀表組合，而得以符合美國藥典(U.S. Pharmacopoeia)純水品質之規範。本實驗以新竹製藥廠純水系統來探討其不同操作條件下所得之純水特性，主要分為前處理單元操作參數及純水循環分佈段操作參數。

原水採用自來水經檢驗均符合飲用水標準，無檢出大腸桿菌，以(Tryptic Soy Agar, TSA)培養基生長效力試驗其金黃色葡萄球菌、綠膿桿菌、枯草桿菌、白色念珠菌、黑麴菌等五株微生物均可有效生長。前處理系統單元以熱水消毒型逆滲透模組(Reverse osmosis, RO)及電去離子系統(Electrodeionization, EDI)為主要純水設備其操作溫度發現以23℃室溫運行導電度最低，50℃流量是23℃的135%。在RO泵浦運行上導電度會隨著流量的增加而遞減，於35Hz以上RO產水量高於RO廢水量是較具經濟效益，且3.6 m3/hr以上可與EDI泵浦間形成正壓力。前處理單元過濾器壓力值隨著RO泵浦頻率的增加而遞減但同樣仍保持管路正壓力。EDI導電度隨著流量增加而遞增，其最適化頻率為35Hz之3.3 m3/hr。純水前處理單元水質分析上，為了符合RO及EDI之進水條件需求，發現軟水機能去除97.7%總硬度，餘氯經由活性碳能去除 >80%，在軟水機、RO及EDI單元導電度去除率各為37.5%、94.1%及95.6%，總有機碳則在RO上能有90%之去除率。

純水循環分佈段的探討上其最適合的溫度操作參數為20℃有較好的導電度及總有機碳表現。進一步結合整體純水系統最適化所有操作條件以運行四週監測純水品質的穩定性，結果顯示每日水質均可符合美國藥典純水規範。研究發現用水期間在每週一至週五總有機碳及導電度數值每日遞減。然而在非用水期間總有機碳在24hr內會遞增45~74 ppb，導電度則遞增0.06~0.17 μS/cm，微生物控制上多數<1 cfu/ml。綜合以上的純水設備及調節參數是可以達到穩定之純水品質。

Purified water is wildly used in the pharmaceutical, food and many other industries. The implementation and validation of purified water system operation requires assembling of many equipment and instrument, and to meet the purified water quality requirement of The United States Pharmacopoeia standard. In this study, the different operating conditions and the water characteristics of the purified water system in Hsinchu pharmaceutical factory is to discuss, operating parameters for purified water system are mainly divided to Pretreatment Unit operation parameters and the purified water circulation distribution section.

The raw water of the purified system were tested in accordance with the standard of drinking water, no detection of E. coli. Five strains of microorganisms, Staphylococcus aureus subsp. aureus, Pseudomonsa aeruginosa, Bacillus subtilis subsp. Spizizenii, Candida albicans, Aspergillus brasiliensis, are used for TSA growth promoting test. Unit of processing system with hot water sanitization type RO and EDI as main water equipment operated at 23 ℃ is found relative low conductivity of water. When the system operated at 50 ℃, it has 135% flow rate than at 23℃. In RO pump running, conductivity will decrease with increasing flow reduction. On more than 35Hz flow rate, production of purified water higher than the quantity of waste water is more cost-effective. On the condition of more than 3.6 m3/hr flow rate, the positive pressure can be formed between RO pump running and EDI pump. Conductivity after EDI will increase by increasing the flow rate. Most suitable frequency of the pump is 35 Hz, 3.3 m3/hr flow rate. Comply with requirements of water quality of purified water pretreatment unit of RO and EDI influent conditions, function of Water softener can remove 97.7% total hardness, the active carbon can remove more 80% residual chlorine, RO and EDI unit conductance removal rate is 37.5%, 94.1% and 95.6%, 90% total organic carbon removal ration rate in RO.

Discussion on water circulation distribution section of the operating parameters of the most suitable temperature for controlling conductivity and total organic carbon quality is at 20℃. Further optimize the whole operation conditions of purified water system to run for four weeks. Monitoring of water quality and stability daily, results showed that water quality can meet the United States Pharmacopoeia purified water specification. Study found that total organic carbon and conductivity value of purified water decreases from every Monday to Friday daily when the water is in use. However, total organic carbon of the non-use water will increase 45~74 ppb in 24hr, conductivity increases 0.06~0.17 μS/cm, microbial control most less than 1 cfu/ml. Summary of the purified water equipment and control parameters mentioned above, water quality can be controlled with highly stability.