Chemical Feed, Storage, and Handling
Know the common treatment chemicals and their hazards: chlorine (gas, hypochlorite, or chloramine), alum/ferric salts, lime, soda ash, polymers, fluoride, and corrosion inhibitors. Understand feed systems (dry feeders, solution feeders, metering pumps), calibration, dose calculations, and feed rate in pounds per day or gallons per day. Learn solution strength, specific gravity, and percent purity adjustments. Storage rules: segregate incompatible chemicals, keep oxidizers away from organics, provide containment, ventilation, and labeling, and rotate stock; hypochlorite degrades with heat and light.
Traps: forgetting to convert percent solution to a mass dose; mixing ppm (mg/L) with pounds per million gallons (1 ppm ≈ 8.34 lb/MG); ignoring specific gravity for liquid feeds; and treating chloramine like free chlorine (different CT and residual measurement).
Rule of thumb: pounds per day = (flow, MGD) × (dose, mg/L) × 8.34. Worked example: 2 MGD at 1.5 mg/L = 2 × 1.5 × 8.34 = 25 lb/day of chemical; if the product is 65% pure, divide by 0.65 to get about 38.5 lb/day of product. Always check units and purity before answering.