Chlorine Dose: Demand + Residual & Decay
Required chlorine dose from demand plus target residual, chemical feed rates, and first-order decay projection.
Formulas
Dose (mg/L) = demand + target residual
Chlorine (lb/day) = dose × flow (MGD) × 8.34
NaOCl (gal/day) = lb Cl₂/day ÷ (strength × 8.34 × SG) — 12.5% at SG 1.2 ≈ 1.25 lb Cl₂/gal
Ca(OCl)₂ (lb/day) = lb Cl₂/day ÷ strength
First-order decay: C(t) = C₀·e^(−kt) · k = ln(C₁/C₂)/(t₂−t₁) · half-life = ln(2)/k
Dose (mg/L) = demand + target residual
Chlorine (lb/day) = dose × flow (MGD) × 8.34
NaOCl (gal/day) = lb Cl₂/day ÷ (strength × 8.34 × SG) — 12.5% at SG 1.2 ≈ 1.25 lb Cl₂/gal
Ca(OCl)₂ (lb/day) = lb Cl₂/day ÷ strength
First-order decay: C(t) = C₀·e^(−kt) · k = ln(C₁/C₂)/(t₂−t₁) · half-life = ln(2)/k
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