工業用水壓力下工業廢水再生之最佳配置

Abstract

全球受氣候變遷影響，導致水資源風險增加，因此各國皆致力於研究不同水管理策略，以降低所帶來的危害。然而台灣亦設立不同水管理方針，包含海水淡化與再生水，但目前再生水政策，對於進行工業廢水再生仍未有明確規劃。另外也透過台灣先前工業廢水再生推動經驗，歸納其失敗原因多為工業廢水再生成本過高，以及工廠用戶對工業廢水再生之水質信心度不足，因此若能解決此兩種因素，將有助於工業廢水再生的推動。 本研究將MBR (Membrane Bioreactor)、UF (Ultrafiltration)、NF (Nanofiltration)、RO (Reverse Osmosis)、EDI (Electrodeionization)、CDI (Capacitive Deionization)，透過不同單元評估最佳技術組合，並以竹科廢水廠為示範說明。除探討最省成本之技術組合於竹科廢水水質適用性、所節省之成本外，亦分析若於廢水再生同時進行水中殘留金屬回收之價值，使水資源與金屬資源皆能重複利用，最後搭配本研究所構想水管理策略，於不同缺水風險下之調控方式。 結果顯示現階情境中最省成本之技術組合為CAS+UF+NF+RO，未來情境則為NF-CDI。並藉國外利用CAS+UF+NF+RO進行當地工業廢水再生，所收集之水質數據，其原廢水水質與竹科相近，且再生水質亦符合台灣再生水標準，因此竹科若利用相同技術則再生可行性高。另評估現階最省成本之技術組合與現今民生污水再生技術，於整年未缺水情況發生時，前者所節省之能耗成本約一億七千萬元台幣。然而於缺水最嚴重情況下，仍可節省約六千萬元。另外水再生過程中若同時進行殘留金屬資源採礦，一年最大潛勢之附加價值約三百五十萬。最後本研究構想之水資源管理策略，於缺水不同程度下，CAS+UF+NF+RO皆能進行分流調控達到水回收需求量，以降低水再生成本與增加工業用戶之用水信心兩項目標。

Climate change is the challenge in all the world, not only increase the water resource risk but other questions, thus many country endeavor to reserch the different water management to reduce the damage of climate change. However, it is also have some water management in Taiwan, including desalinating sea water and reclaimed wastewater, but it still does not have clearly reclaimed water policy in industrial wastewater. On the other hand, we can get the failure reason for the industrial wastewater recycling with experience in Taiwan before. The reason including the cost of reclaimed water and the confidence of reclaimed water to use in the process of the industry. Consequently, it is useful to promote the policy of the industry reclaimed water if resolve these question. This study used different water technologies, including MBR, UF, NF, RO, EDI, and CDI to evaluate the best combination of units, and used the Hsinchu Science Park Wastewater Treatment Plant as a demonstration. Besides to discussing the appropriate of Hsinchu Science Park Wastewater Treatment Plant wastewater quality with the best wastewater treatment process and the cost savings of the energy by replacing the best technology combination, it also analyzes the added value of water resource recovery during wastewater regeneration, make both of the water and metal resources can be reuse. Finally, use the water management strategy of this study method, the two goals of reducing reclaimed water costs and increasing water confidence of industrial users will be achieved. The results show that in the current situation, the best water treatment process is CAS+UF+NF+RO, while the future situation is NF-CDI. And the abroad industrial wastewater plant which using CAS+UF+NF+RO technology, its wastewater quality is similar to the Hsinchu Science Park Wastewater Treatment Plant, so it has the feasibility to use in Taiwan industry waster water plant. In addition, also compare the best water treatment process with the water management strategy of this study in the current situation and the Municipal Wastewater Treatment Plants, the CAS+UF+NF+RO process can save about 170 million NT when there is no water shortage throughout the year. However, in the worst of water shortage, the energy cost can still save about 60 million NT. And during the water regeneration process, the residual metal in wastewater can be mined of the maximum profit potential is about 3.5 million. Finally, the water management strategy of this research also provided the method of control in a different water shortage situation, to reduce the cost of water recycling and increase the water confidence of industrial users.