DETERMINATION OF TOXIC INHIBITION POTENTIAL FROM INDUSTRIAL DISCHARGERS TO A POTW USING A RESPIROMETRIC ASSAY

摘要

Upset events due to the inflow of toxic chemicals are a critical issue for wastewater treatment facilities. Understanding the source-effect relationship between toxic chemicals and treatment plants can lead to appropriate strategies for preventing future events and/or establishing corrective action plans for operator decision-making. Respirometry is among the tools that are used to identify toxic sources that can have an impact on process performance. Although it does not identify the chemical(s) in a wastewater that lead to process upset, respirometry can serve as a viable first step to identify wastewater streams that have the potential to disturb biomass metabolism in a wastewater bioreactor. A respirometric assay protocol was developed for this study to allow a regional wastewater treatment facility (RWTF) under the influence of several industries to screen industrial wastewaters for inhibitory properties based on two classifying criteria. All five industrial wastewaters tested revealed inhibitory properties, but one plant was routinely uninhibitory. Large day-to-day variations were found, illustrating the need for a large database of results for comparison over time. Additionally, a small volume contributor that was thought by the utility to be an unlikely source of problems contributed significantly to the wastewater oxygen demand and frequently demonstrated inhibitory properties. The modified respirometric procedure provided the RWTF with a protocol upon which it may be possible to identify industrial sources that cause process upset. A complimentary sample storage procedure and data analysis protocol were also suggested as part of the analytical procedure.