泡湯已成為國人主要休閒活動，為達溫泉資源保育目的，溫泉水需考慮採用循環及回收再利用，此時溫泉水需做殺菌處理。
本研究使用紫外燈(Ultraviolet A、Ultraviolet C)、日光燈、及暗室配合添加無臭、無毒性之二氧化鈦光觸媒，比較各種光催化條件對關仔嶺泥漿溫泉水中大腸桿菌enterotoxigeic E.coli (ETEC O4)的殺菌效果。
研究結果顯示，對富含碳酸氫鈉及氯化物之泥漿溫泉水中大腸桿菌做殺菌處理，不同的光輻射條件、光強度、輻照時間和二氧化鈦添加量都會影響光催化殺菌的效率。因為不同光輻射條件中的暗室與日光燈，並無殺菌效果，反而時間愈長，大腸桿菌增多；而UVA及UVC不同光強度之殺菌效果有明顯差異，乃因波長不同而導致，然而輻照時間愈長，殺菌效果愈佳。其中也發現以UVA照射添加0.12g/L二氧化鈦對泥漿溫泉中大腸桿菌的光催化效果最佳，但是添加太多二氧化鈦殺菌效果反而不好；而UVC照射添加0.2g/L二氧化鈦對泥漿溫泉中大腸桿菌的光催化效果最佳。
研究最後得知，經由離心過後的溫泉水殺菌效果比未經離心過的溫泉水要來的好，因為泥漿溫泉水中含有許多泥沙，進而使光穿透性受阻，導致殺菌效果受到影響。
關鍵詞：光輻射、二氧化鈦、大腸桿菌、光催化、泥漿溫泉 Taking a hot spring bath is an important leisure and entertainment in Taiwan. For resource conservation of hot spring, hot springs circulation and recycling need to be done with sterilization.
The aim of this study is to explore the sterilization effect of both different photo-irradiation (UVA, UVC, solar irradiation, fluorescent lamp and darkroom) and dosing with odorless and non-toxic photocatalyst on E coli. (ETEC O4) in the mud hot spring of Guanziling under batch tests.
Results show that the sterilization of E coli. (ETEC O4) in the mud hot spring of sodium bicarbonate chloride type was affected by intensity of photo-irradiation, photo-irradiation time, doage of titanium oxide. Results also reveal that the effect of photocatalysis was the best by dosing with 0.04 g/L titanium oxide, however, more than this dosage, the more dosage led to the worse sterilization effect. The dosing of titanium oxide leading to worse effects on the sterilization of ETEC O4 might be caused by some reasons of titanium oxides being not nano scale, also not calcined and modified, as well as which scattering possibly the penetrating of light.
Keywords：photo-irradiation、titanium oxide、E coli.、photocatalysis、 mud hot spring.
