Friday, June 9, 2023, 11:20 PM
Site: Pa. DEP Operator eLearning Center
Course: Pa. DEP Operator eLearning Center (PADEP)
Glossary: Course Glossary

Detected Contaminant

Any contaminant detected at or above its detection limit.

  • (CCR01)Consumer Confidence Report (CCR) Overview (2338)

Detection Limit

The amount of a substance with that EPA has determined to be the minimum concentration that can be measured and reported with 99% confidence that the true value is greater than zero.

  • (CCR01)Consumer Confidence Report (CCR) Overview (2338)

Detention Time

The theoretical time that a parcel of water or other liquid spends in a particular treatment unit or reservoir.

  • (COA01) Coagulation – Part 1: The Chemistry of Coagulation (1248)

Diatomaceous Earth

A fine material made up mostly of the skeletal remains of single cell, microscopic algae with a rigid, box-like internal structure consisting mainly of silica.

  • (DBP40) Enhanced Coagulation – Basics (1280)

Digester Capacity

The total volume in gallons that a digester(s) can hold, or the volume used during the monitoring period, if not operating at full capacity.

  • (BIO10) Estimating Sludge Volume (2343)

Discharge Monitoring Report

Discharge Monitoring Report (DMR)


Substances that are added for the purpose of killing or inactivating the pathogenic (disease-causing) bacteria found in water.

Chlorine, Chloramines, & Chlorine Dioxide are disinfectants.

  • (DBP01) DBP Rule – Overview (1282)
  • (DBP02) DBP Rule Monitoring and Reporting – Job Aids (1283)
  • (DBP10) DBP Rule Monitoring and Reporting for Chlorine⁄Chloramines (1284)
  • (DBP13) DBP Rule Monitoring and Reporting for TTHM⁄HAA5 (1285)

Disinfection Byproducts Precursors

Organic substances that combine with disinfectants to form potentially carcinogenic compounds such as HAA5’s and TTHM’s.

  • (DBP43) Jar Testing for Process Control of Conventional Filtration: Part 1 (2019)

Dissolved Oxygen

Dissolved Oxygen (DO)

A measure of the amount of free or molecular oxygen dissolved in water, expressed as:

  1. mg/L, which is the absolute amount of oxygen dissolved in the water mass or
  2. the percentage saturation of water with O2 (% sat).
    • (BNR01) Nitrification and Denitrification – An Introduction to Nitrogen Removal (1485)
    • (BNR02) Nitrification Factors – Suspended Growth Treatment Systems (1821)


DMR – Discharge Monitoring Report

  • (BIO10) Estimating Sludge Volume (2343)