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Technical Proficiency and Best Practices Flashcards

7 cards from real ABC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Technical Proficiency and Best Practices flashcards as text

  1. Which operational parameter is used to control the age of biological solids in an activated sludge system?

    Answer: Sludge retention time (SRT) also called mean cell residence time

    SRT (or MCRT) controls how long biological solids remain in the system, directly affecting microbial community composition and treatment efficiency.

  2. A drinking water system detects a total coliform-positive sample. Under the Total Coliform Rule, the operator must first:

    Answer: Collect repeat samples within 24 hours from the same site and adjacent sites

    The TCR requires repeat samples be collected within 24 hours from the original site plus at least two adjacent sampling points to determine if the positive is isolated.

  3. An operator needs to calculate the chlorine dose required to achieve a 2.0 mg/L residual in a reservoir that has a chlorine demand of 3.5 mg/L. What dose is required?

    Answer: 5.5 mg/L

    Chlorine dose = demand + residual = 3.5 + 2.0 = 5.5 mg/L; the dose must satisfy both the demand and leave the desired residual.

  4. In wastewater treatment, which test is used to estimate the oxygen demand of slowly biodegradable or non-biodegradable organic compounds?

    Answer: Chemical oxygen demand (COD)

    COD measures all oxidizable material chemically, including compounds resistant to biological breakdown that BOD5 would not fully capture.

  5. When should an operator use a portable gas detector before entering a wet well?

    Answer: Before every entry regardless of previous conditions

    Atmospheric conditions in confined spaces like wet wells can change rapidly, so testing before every entry is required regardless of prior safe entries.

  6. What is the primary disadvantage of using sodium hypochlorite (liquid bleach) compared to gaseous chlorine for disinfection?

    Answer: Sodium hypochlorite degrades over time, reducing effective strength

    Sodium hypochlorite degrades when exposed to heat, light, and time, losing potency and requiring frequent strength verification and proper storage.

  7. Which action is considered a best practice for maintaining accurate plant records under regulatory requirements?

    Answer: Completing log entries in real time or as soon as possible after readings are taken

    Real-time or near-real-time entries ensure accuracy, support compliance audits, and provide legally defensible documentation of plant operations.