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THE TOXICITY REDUCTION EVALUATION PROTOCOL FOR MUNiaPAL WASTEWATER TREATMENT PLANTS:
CASE HISTORIES AT HIGH POINT AND FAYETTEVILLE, NC
| 题名： | THE TOXICITY REDUCTION EVALUATION PROTOCOL FOR MUNiaPAL WASTEWATER TREATMENT PLANTS: CASE HISTORIES AT HIGH POINT AND FAYETTEVILLE, NC |
| 作者： | Francis A. DiGiano Marilyn Maerker Tory L. Champlin Maria V. Frey |
| 关键词： | wastewater；protocol；evaluation；stories；plant；point；reduct；ants；evil；case |
| 摘要： | A toxicity reduction evaluation (TRE) is comprised of performance evaluation of the publicly-owned treatment works (POTW); toxicity identification evaluation (TIE); and a Toxicity Source Evaluation (TSE). The specific objectives of this research were to: challenge the TIE protocol with target compounds to determine whether the toxicity could be properly classified; apply the TIE and TSE protocols to two case studies (High Point, NC and Fayetteville, NC) where pass-through toxicity was highly variable; and investigate the potential for return activated sludge to desorb components that may cause acute toxicity. Testing of the TIE Phase I protocol with five target compounds (four organic compounds and one metal) showed that false positive and false negative removals of toxicity can occur. Elution of the CIS column with methanol/water fractions (TIE Phase II) showed that toxicity is eluted in several different fractions for a single compound. Only a weak relationship was found between the fraction eluting toxicity and the polarity of the compound. Identification of the sources or nature of acute toxicity when events were sporadic was not solved in the High Point study. One event was shown to be caused by metal plating industries discharging nickel. Modifications were made to the refractory toxicity assessment (RTA) protocol to simplify its use. Also, the protocol was modified to use chronic toxicity as the end-point rather than acute toxicity; four (all organic chemical manufacturers or users) gave very low averages of young produced. Four TIES at the Fayetteville, NC facility showed that the C18 SPE column removed acute toxicity completely in each instance. Other tests implied ammonia could have contributed to toxicity but this was not consistent with removal of toxicity by the C18 column. Elution of the C18 column in three of tne TIEs showed that all the toxicity was found in the 75 to 90% methanol fractions and most was in the 80-85% fractions. RTA tests suggested five potential industrial contributors of toxicity. Return activated sludge was not found to be more toxic than whole effluent in the case histories examined. However, a sample from another treatment facility indicated concentration and release of toxicity by biomass. TIE Phase I protocol can provide the proper direction for further narrowing of potential toxicants but more data are needed with mixtures of target compounds to show reliability. The RTA protocol should be streamlined to make it more practical to apply. The development of **real-time'' measures of aquatic toxicity is essential if sporadic sources are to be eliminated. |
| 报告类型： | 科技报告 |
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