Question 12.5: FEEDING DRY CHEMICAL TO A WATER TREATMENT PLANT Dry chemical...
FEEDING DRY CHEMICAL TO A WATER TREATMENT PLANT
Dry chemical feeders all have their feeder calculation curves provided by the feeder manufacturers. Typically the dry chemical feed rate is calculated based on the WTP flow rate and the required chemical dosage. Once the dry chemical feed rate is calculated, from the feeder calculation curve, the feed setting is determined to feed the exact amount of dry chemical (lb/day or kg/day). Determine the lime dosage in lb/day and kg/day, required to treat 15 MDG (56.78 MLD) at Albany WTP assuming the required lime dosage is 10 mg/L.
1 (US Customary System):
1 mg/L = 8.34 lb/MG
Lime dosage = (15 MGD)(10 × 8.34 lb∕MG) = 1,251 lb∕day
The WTP operator should find and set the correct lime feed setting based on the lime dry feeder calculation curve, and feed 1,251 lb/day to water.
2 (SI System):
1 mg/L = 1,000,000 mg/ML = 1,000 g/ML = 1 kg/ML
Lime dosage = (56.78 MLD)(10 × 1 kg∕ML) = 567.8 kg / day
The WTP operator should find and set the correct lime feed setting based on the lime dry feeder calculation curve, and feed 567.8 kg/day to water.