Question 1

How do you calculate chlorine dosing for water treatment?

Accepted Answer

Product feed (kg/day) = target dose (mg/L) × flow (m³/day) ÷ (1000 × available chlorine fraction). Example: dosing 2 mg/L into 500 m³/day using 65% calcium hypochlorite needs 2 × 500 ÷ (1000 × 0.65) ≈ 1.54 kg/day of product. For liquid sodium hypochlorite the same formula gives kg/day of solution; divide by its density (~1.2 kg/L) for litres.

Question 2

What glycol concentration is needed for freeze protection?

Accepted Answer

For chilled-water and process loops, typical protection targets map to approximate volume concentrations: -8 °C ≈ 20%, -14 °C ≈ 30%, -22 °C ≈ 40% for MEG (propylene glycol runs slightly higher for the same protection). Glycol volume = system volume × concentration. Always verify the final mixture with a refractometer, and use inhibited glycol matched to the system metallurgy.

Question 3

How is cooling tower blowdown calculated from cycles of concentration?

Accepted Answer

Evaporation E (m³/h) ≈ 0.00153 × recirculation rate (m³/h) × ΔT (°C). Blowdown B = E ÷ (C − 1), where C is cycles of concentration. Make-up = E + B (drift neglected). Example: 500 m³/h recirculation with a 6 °C range at 5 cycles gives E ≈ 4.6 m³/h and B ≈ 1.15 m³/h. Inhibitor feed (kg/day) = target residual (mg/L) × blowdown (m³/day) ÷ 1000.

Question 4

What is the typical antiscalant dose for an RO plant?

Accepted Answer

Most RO antiscalants dose at 2–4 mg/L into the membrane feed stream — the exact figure comes from a projection run against your feed-water analysis. Feed rate (g/h) = dose (mg/L) × feed flow (m³/h). A 100 m³/h train at 3 mg/L consumes 300 g/h ≈ 7.2 kg/day ≈ 216 kg/month. We run projections free of charge against your water analysis.

Water Treatment Dosing Calculators

Chlorination Feed Rate

Glycol Freeze Protection

Cooling Tower Cycles & Blowdown

RO Antiscalant Consumption