General Operations
General Operations
This domain tests the day-to-day management of a utility: math, records, preventive maintenance, asset management, energy, instrumentation, emergency response, and communication. Exam questions often combine a calculation with an operational judgment, such as chemical usage, pump run time, or documentation.
Core rules
- Use consistent units; convert gpm to MGD by dividing by 694.4 (approximately).
- Chemical pounds formula: lb/day = mg/L × 8.34 × MGD.
- Preventive maintenance follows manufacturer intervals and operating experience; keep histories.
- Calibrate instruments and verify online readings against grab samples.
- Emergency plans need power, chemical, staffing, and communication contingencies.
Worked example
A plant doses 20 mg/L alum at 1.5 MGD. lb/day = 20 × 8.34 × 1.5 = 250.2 lb/day of active alum. If the purchased solution is 50% strength, commercial product = 250.2 ÷ 0.50 = 500.4 lb/day. The reasoning: the formula gives active chemical; divide by strength to get product, not multiply.
Traps
Using 8.34 with gpm instead of MGD; multiplying by strength instead of dividing; trusting a SCADA value without calibration; skipping maintenance records; planning for normal power only.