Primary Clarification or Equivalentsearch for term
The level of treatment that typically would be provided by one or more treatment technologies under peak wet weather flow conditions. Options for defining primary clarification include a design standard (e.g., side wall depth and maximum overflow rate), a performance standard (e.g., percent removal), or an effluent standard (e.g., concentration of pollutants). “Equivalent to primary clarification” is site-specific and includes any single technology or combination of technologies shown by the permittee to achieve primary clarification under the presumption approach. The permittee is responsible for showing equivalency to primary treatment as part of the evaluation of CSO control alternative during LTCP development. Primary clarification is discussed in more detail in the Combined Sewer Overflow Guidance for Long-term Control Plan (EPA 1995).