Decision Flow Charts for Risk Assessment and Application Guidance for Passive Treatment Chemicals at Industrial and Construction Sites

This presentation covers an approach to evaluate the risk associated with pre-storm application (passive use) of treatment chemicals based on factors that affect the potential toxicity in effluent water. The decision framework was developed using a literature review of existing best management practices, guidance documents, existing regulations, studies of environmental impacts, and input from a technical advisory committee. Conditions where impacts are unknown are identified, and regulatory options for monitoring or avoiding practices with unknown impacts will be discussed. This presentation will review the current state of practice of chemical coagulants on construction sites and will also provide an overview of guidance flowcharts and maximum likely concentration calculators developed to estimate concentrations in both land and water application of passively dosed chemicals. The resulting work products provide a decision framework that directs users toward an environmentally safe passive use of treatment chemicals at construction and industrial sites. This project may also inform future regulatory policy and guidance.