Sizing the System & Sizing the Chlorinator

Sizing the System

Sizing the Filters When sizing the filtration components in a full line chlorination system, the basic rule for filtration applies - match the pump flow rates to the backwash rates and service flow rates. Remember “Bigger is not better and smaller is not right either.” Sizing the Chemical Feeder Pump Need to know: Chlorine demand for water treatment To do a chlorine demand test (should be performed on-site): • 1 gallon of fresh raw water • Sample of chlorine which will be used in the system • Chlorine test kit

Goal: • To achieve a residual chlorine level of 1.0 - 1.5 ppm (free chlorine test) • If used to precipitate hydrogen sulfide, a residual of 3 ppm should be obtained Procedure: • Add 3 drops chlorine to the gallon of raw water • Allow to stand for 5 minutes • Test water with the chlorine test kit • If no chlorine residual is indicated, add more drops in sets of 3 until a chlorine residual of 1.0 - 1.5 ppm is obtained • Measure the pumping rate of the pump system • Multiply the pumping rate by the number of drops of chlorine required. This will equal the number of drops of chlorine required per minute

Example: 26 drops required x 6 gpm pumping rate = 156 drops per minute x 60 minutes per hour = 9,360 drops per hour ÷ 75,000 drops per gallon = 0.125 gallons of chlorine per hour

Sizing the Chlorinator

Select a chlorinator which will run at approximately 30-80% injection. Most chlorinators will inject more than required. Therefore, dilute the chlorine with “clean” treated soft water to obtain the quantity required versus the pump’s efficient setting. Example: 0.125 gallons of chlorine required per hour The pump selected will inject 1.0 gallons per hour 1.0 maximum output of chemical feed pump ÷ 50% optimum pump setting = .5 gallons per hour ÷ 0.125 gallons per hour required = 4 This is your dilution ratio - 4:1