COMPLYING WITH NPDES REQUIREMENTS.

This paper reviews approved instrumental methods that may be used to meet the requirements of the National Pollution Discharge Elimination System, along with recommended quality assurance techniques. Instrumental techniques are included that allow the use of such instruments as pH meters, ion selective electrode (ISE) meters, automated colorimetric analyses, gas chromatography, spectrophotometers, atomic absorption units, balances, total organic carbon (TOC) analyzers, proportional or scintillation counters, conductivity meters and nephelometers. Pollutants that can be measured by these instrumental techniques have been categorized by equipment needs. Topics discussed in some detail include: instrumentation; quality assurance; precision and accuracy; and two areas of need (water and wastes) in the future.