Friday, May 7, 2021, 6:28 AM
Site: Pa. DEP Operator eLearning Center
Course: Pa. DEP Operator eLearning Center (Home)
Glossary: Course Glossary

90th Percentile Tap Sample Result

Identification of the 90th percentile tap sample result is accomplished by following two steps:

  1. Rank all tap sample results from lowest to highest.
  2. Multiply the total number of samples by 0.9.
  • (LCR11) LCR – Initial Planning, Monitoring and Reporting (1488)

Critical Asset

Components of a water or waste water treatment system that are necessary to meet mission objectives (providing drinking water that meets or exceeds the National Drinking Water Standards, providing adequate water pressure to meet public safety needs, maintaining water service to critical users, maintaining wastewater collection system to protect public health, and providing wastewater treatment that meets the National Pollution Discharge Elimination System standards.
  • (SEC01) Securing Drinking Water and Wastewater Treatment Facilities 2954


ACC - Alternative Compliance Criteria Alternative criteria that can be used to achieve either monthly or annual compliance with the enhanced coagulation requirements of the DBP Rule.
  • (DBP42) Enhanced Coagulation – Advanced Concepts & Alternative Compliance Criteria


A condition in which a substance yields H+ ions when it dissociates in water, resulting in a lowering of pH.
  • (DBP40) Enhanced Coagulation – Basics (1280)<\ul><\li>


The concentration of H+ ions in a solution, measured as pH.
  • (DBP43) Jar Testing for Process Control of Conventional Filtration: Part 1 (2019) <\ul><\li>

Action Level

  1. Action Level (AL)
    • (LCR10) Lead and Copper Rule – Basics (1423)
    • (LCR11) LCR – Initial Planning, Monitoring and Reporting (1488)
  2. A level at which the system must take additional action to reduce lead or copper levels and inform consumers about the actions they can take to lower exposure to lead in drinking water.
    • (CCR01)Consumer Confidence Report (CCR) Overview (2338)

Activated Silica

A coagulant aid that is created on-site by neutralizing sodium silicate.
  • (COA02) Coagulation — Part 2: Coagulation Chemicals (1249) <\ul><\li>

Activated Sludge Process

A biological treatment process in which a mixture of wastewater and activated sludge is agitated and aerated. The activated sludge is subsequently separated from the treated wastewater by settlement and recycled or wasted. Although the configuration of activated sludge plants vary, the activated sludge process includes one or more aerated reactors that keep the solids in suspension; a liquid-solids separation device known as a clarifier; and a method of recycling the separated sludge from the clarifier back to the aerated reactor(s).
  • (BNR01) Nitrification and Denitrification – An Introduction to Nitrogen Removal (1485) <\li>
  • (BNR02) Nitrification Factors — Suspended Growth Treatment Systems (1821)
  • (BIO10) Estimating Sludge Volume (2343) <\ul><\li>

Acute health effects

Adverse effect on human health as a result of short-term exposure. Acute health effects occur within hours or days of the time that a person consumes a contaminant.
  • (DBP14) DBP Rule Violations for Pa. PWSs using Chorine⁄Chloramines (1825) <\li>
  • (PNR01) Public Notification – An Introduction for NCWSs (2332) <\li>
  • (PNR11) Public Notification – Violations and Tiers for NCWSs (2333)(1488) <\li> <\ul>

Additional Routine Monitoring

  1. This refers to the requirement that any PWS, which collects fewer than five routine coliform samples per month, must collect at least five routine coliform samples per month, must collect at least five routine samples the very next month following a coliform-positive test result. This requirement can be reduced to no less than one sample the next month, with DEP approval, if the PWS has taken corrective actions before the end of the next month.
  2. Extra routine samples PWSs must collect during the month following a coliform positive test result. These extra samples can be reduced to no less than one sample the next month if the PWS has taken corrective actions before the end of the next month.
  • (TCR01) Total Coliform Rule – Overview (1424)
  • TCR02) Total Coliform Rule – Monitoring And Reporting Requirements (1425)
  • (TCR03) Total Coliform Rule – Maintaining Compliance (1426)