醫院排放水的毒性鑑定評估

Abstract

對於廢水處理廠的好壞,常以物化污染參數如懸浮物(SS),需氧量 (BOD)來 評定其處理效果,但被評定出的好處理廠並不代表它不會有毒物的產生。 為此本研究特別引用美國環保署於1989年所制定的毒性鑑定評估( Toxicity Identification Evaluation,TIE)為準則,以魚類急毒性及 Microtox兩種試驗檢測毒物,針對國內綜合型醫院的廢水處理廠作毒性鑑 定。傳統毒性鑑定是以化學分析為基礎,只針對法定所列管的毒物作評定, 但對於非列管毒物就束手無策,因此美國環保署發行毒性鑑定評估(TIE, phaseI.II.III)手冊,鑑定評估的原理是利用物化分離方法 ,先將毒物依 化學屬性分類,再利用毒性試驗配合化學分析找出廢水的毒性來源且確認, 進而使毒物減量工作有處理的依據。醫院廢水的採集分為三個地點,原水 口,終沉池,排放口。毒性鑑定結果,原水口毒性來源大部分為極性較低的 有機物。活性污泥二級處理後所溢流的廢水沒有毒性反應,此顯示傳統二 級處理對於低極性的有機物具有控制效果。排放水的廢水經毒性鑑定其毒 性來源為消毒劑所產生的餘氯,此表示醫院廢水處理流程仍需改善。利用 Microtox和魚毒兩種毒性試驗,針對醫院三種廢水所作出的相關性研究,發 現其線性相關極佳(R2=0.9748),因此Microtox可成為魚毒替代性實驗。 A well maintained plant,operating under design conditions may be capable of providing an acceptable level of treatment for conventional ordesign paraments,and still allow toxic compounds to be released to the environment. The study is based on the T. I.E.by U.S.EPAto determine the toxic compounds of hospital effluent.In addition to the correlation between the Microtox test and fish acute toxicity test. A T.I.E. was developed to identify the fractions of a complex wastewater efflunt contributing to toxicity. The T.I.E. isbased on sequential physical/chemical fractionsm ofthe effluent with associated toxicity testing using the aquatic organism. before and after each fractionation treatment,acute toxicity test are conducted to determine the efficiency of the treatments in removing toxicity. The T.I.E. can determine whether or not the effluent of the toxicity is associate with filterable solids, the polar or The results suggested that the major toxic fraction of hospital effluent sample is residual chlorine. Microtox and freshwater fish acute toxicity test showed similar sensitivities in the hospital effluents.