以太陽光驅動過硫酸鹽去除廢水中抗生素之效能探討

Abstract

為減少新興污染物排放至環境水體，臺灣環境部近年加嚴醫院放流水管理規範，不僅新增氨氮與自由餘氯排放標準，亦將抗生素及其他新興污染物納入監測項目。由於傳統生物處理程序難以有效去除多數藥物，且為降低鹵化消毒副產物 (Disinfection Byproducts, DBPs) 生成，自由餘氯排放濃度限制為 2 mg/L，因此需尋找兼具高降解效率與低副產物生成之替代氧化方式。 本研究評估過二硫酸鹽 (Peroxydisulfate, PDS) 應用於醫院廢水中微量抗生素降解之可行性，比較紫外光(UV) 與太陽光 (Solar) 活化之 PDS 系統( UV/PDS 與 Solar/PDS)，並以 Solar/Chlorine 作為比較基準。 結果顯示，UV/PDS 與 Solar/PDS 在廢水基質中皆具有良好的降解性，於反應 10分鐘或60 分鐘後，對 Sulfamethoxazole (SMX)及 Levofloxacin (LVX) 之去除率均達約 50%，且與以超純水為基質之實驗結果趨勢一致。相較之下，Solar/Chlorine 僅對 SMX 具有顯著降解效果，推測因自由餘氯與溶解性有機物 (Dissolved Organic Matter, DOM) 發生反應而快速消耗。另一方面，大環內酯類抗生素 Clarithromycin (CLR) 及 Azithromycin (AZM) 於各系統中皆呈現高度難降解特性；而 Sulfamethoxazole 主要代謝物 N-acetyl-sulfamethoxazole (NASMX) 僅能透過 UV 活化系統有效降解，顯示 UV 對特定代謝物去除具有關鍵作用。此外，PDS 系統產生之鹵化消毒副產物濃度顯著低於氯系統，各處理程序亦皆未造成顯著急性細胞毒性，且基因毒性隨反應進行呈下降趨勢。 本研究顯示 PDS 為醫院廢水處理中具發展潛力之替代氧化劑。抗生素及其代謝物於自由基氧化過程中展現不同之反應特性，顯示應依目標污染物特性選擇適當之 PDS 活化策略，以提升污染物去除效率，同時降低消毒副產物生成及毒理風險，作為未來醫院廢水高級處理技術之參考。

To reduce the release of emerging contaminants into environmental waters, recent regulatory actions by Taiwan’s Ministry of Environment have tightened hospital effluent standards by imposing limits on ammonia nitrogen and free chlorine, and have introduced new monitoring requirements for antibiotics and other emerging contaminants. Since many antibiotics are poorly removed by conventional biological treatment, and free chlorine is now capped at 2 mg/L to reduce the formation of halogenated disinfection byproducts, alternative oxidants with lower potential for byproduct formation are needed. This study evaluates peroxydisulfate (PDS) as a candidate oxidant for degrading trace-level antibiotics in hospital wastewater. Two PDS activation strategies (UV/PDS and Solar/PDS) were examined, with Solar/Chlorine included as a benchmark. Results demonstrated that both the UV/PDS and Solar/PDS systems exhibited effective degradation performance, achieving approximately 50% removal of sulfamethoxazole (SMX) and levofloxacin (LVX) after 10 min (UV/PDS) or 60 min (Solar/PDS) of treatment, consistent with the trends observed in Milli-Q water. In contrast, the Solar/Chlorine benchmark was effective only against SMX, likely due to the rapid consumption of free chlorine by reacting with dissolved organic matter (DOM). Notably, macrolide antibiotics, including clarithromycin (CLR) and azithromycin (AZM), remained highly recalcitrant across all tested systems. Regarding metabolite degradation, UV/PDS was the only process capable of consistently degrading N-acetyl-sulfamethoxazole (NASMX), suggesting that UV activation plays an important role in its degradation. Concurrently, DBP profiling revealed that PDS-based processes generated significantly lower concentrations of halogenated DBPs compared to chlorine-based AOPs. Toxicological assessments further indicated that while none of the processes induced significant acute cytotoxicity, genotoxicity decreased over the course of treatment. In summary, these findings demonstrate that PDS is a promising alternative oxidant for hospital wastewater treatment. The distinct reactivity of antibiotics and their metabolites under radical-based oxidation underscores the importance of selecting appropriate PDS activation strategies according to target contaminants, thereby maximizing degradation efficiency while minimizing DBP formation and toxicological risks in practical wastewater treatment applications.