醫院廢水處理設施所產生致病性生物氣膠之研究

Study of Bacterial Aerosols from Treatment Facilities of Hospital Wastewater

由於醫院廢水內含大量致病性微生物，其廢水作生物處理時，會因曝氣致使大量微生物逸散於周圍空氣中，這些致病性生物氣膠對操作人員、醫院病人及附近居民之健康皆有潛在之威脅。因此對曝氣系統所產生物氣膠之問題更不容忽視，故本研究擬針對這些問題加以評估探討，然而因醫院廢水中致病菌之含量甚多，故本研究主要以致病菌為探討對象。結果發現密閉式污水處理廠所產生生物氣膠微生物含量遠大於比較開放式及半開放式。而生物氣膠之發生源大多來自進流口、調勻槽及曝氣槽並污泥處理設施。各處理設施所產生生物氣膠濃度A醫院（半開放式）入流口之含菌量為8,800 CFU/m3，調勻槽為4,200CFU/m3，曝氣槽為21,000 CFU/m3，B 醫院（開放式）入流口之含菌量為2,500 CFU/m3，調勻槽為2,900 CFU/nP，曝氣槽為5,000CFU/m3，C醫院（密閉式）入流口之含菌量為11,670 CFU/m3，曝氣槽為89,000CFU/m3。故其處理設施產生之生物氣膠亦較Sirpa Laitinen所研究之工業廢水處理設施產生之生物氣膠為高。在醫院廢水生物氣膠中有的菌種，但在工業廢水中沒有的菌種為Proteus mirabilis、Staphylococcus epidermidis、Pseudomonas aeruginosa、Flavobacteria spp.、Staphylococcus suprophyticus、Citrobacter diversus、Xanthomonas spp.、Acinetobacter spp.。醫院廢水處理過程所產生之生物氣膠，所分離之菌種與院內感染之菌種非常吻合。因此醫院廢水處理過程所產生之生物氣膠亦可能為院內感染之微生物發生源之一。而圍牆圍住對周遭之生物氣膠量有很大的阻絕效果，避免擴散污染廠區。但亦會使微生物蓄積在廠區內對操作人員產生健康上之威脅。故如何解決醫院廢水處理過程中，所產生生物氣膠之問題，實為重要之課題。

Because of the aerosolization process of wastewater treatment, tremendous amount of microbial pathogens in hospital wastewater may become airborne and impose potential health threat on hospital personnel, patients and surrounding residents. Purpose of this study is, therefore, to evaluate the bioaerosol level in the air of wastewater treatment facilities of three hospitals. The results showed that bioaerosol concentration in the enclosed-type facility is higher than that measured in semi-open and almost-open facilities. The major sources of bioaerosol exposure are found at the wastewater entering point, equalization basin and aeration basin. Bioaerosol concentrations were 8800 CFU/m3, 4200CFU/m3 and 21000CFU/m3, respectively, at the entering point, equalization basin and aeration basin for hospital A; 2500 CFU/m3, 2900 CFU/m3 and 5000CFU/m3 for hospital B, all 11670CFU/m3 (entering point) and 89000 CFU/m3 (aeration basin) for hospital C. The level of bioaerosol exposure in this study was found to be higher than that from industrial wastewater facilities by Sirpa Laitinen. In addition, microbial species were identified to be similar to those found in nosocormial infection. It implies that bioaerosols from the wastewater treatment process may be one of major sources associated with nosocormial infection. Wastewater treatment facilities with enclosed type might block bioaerosol dispersion out of hospitals, but could accumulate bioaerosols and cause potential health hazard for healthcare workers.