Collecting the Drops
"Rules of Thumb"
Sanitary Water Usage
- 10 -25 gallons per person per shift
- The lower value is used where there are just toilets. A higher value is used where there are toilets, showers, full kitchen services, that is, food preparation and dish washing.
Wastewater Streams from Water Treatment Operations
- Number of sprinkler heads x the flow capacity per head (e.g.; 2.5 gpm x the duration [minutes] of water application)
- Inspect the irrigation system during operation to determine if there are leaks from broken sprinkler heads and from water distribution lines.
Cooling Tower Usage
- Reverse Osmosis Reject Flow
- Reject stream generally ranges from 10 to 50% of the feed to the system depending on the salinity and the desired purity.
- Reject flow can be higher than the indicated range. RO reject streams can be used as cooling tower makeup if the water is softened prior to the reverse osmosis system.
- Windage Loss
- Commonly 0.1 to 0.3 % of the Recirculation Rate
- The tower recirculation rate can be obtained from the manufacturer’s literature and or head versus flow curve for the pump.
- Boiler Blow Down
- Range of 4 to 8 % of boiler makeup
- 1 drip/second
- 10,000 l/year or 2,642 gal/year
- Water Flow Estimation
- Use a bucket and stop watch
1155 Fifteenth Street, NW,
Washington, DC 20005