Page 136 - WaterSense at Work

October 2012
Food Disposals
Run cold water through the food disposal system instead of hot water. This will
reduce the energy use associated with heating the water. It will also help to keep
the system cool.
Regularly inspect and clean the food disposal system to make sure the blades are
sharp and the system is not clogged with debris.
Retrofit Options
To reduce the water use associated with a traditional garbage disposal, consider
installing a device that can sense the disposal motor’s load and regulate the amount
of water necessary. These devices can reduce the idle flow rate when the garbage
disposal is not in use, from between 2.0 and 15.0 gpm to 1.0 gpm, thus saving a sig-
nificant amount of water. Also, consider installing a timer to stop the flow of water to
the garbage disposal after 15 minutes, so that the user must periodically reactivate
the system.
Replacement Options
When purchasing a new food disposal system or looking to replace an existing food
disposal system, consider these options:
Purchase a garbage disposal with a load sensor to regulate the amount of water
conveyed through the disposal depending upon whether it is in use or idling.
Install a food pulper or food pulper/strainer combination system, which can
recycle 75 percent of the water used for the food disposal process.
Replace mechanical food disposal systems with food strainers, which use little to
no water.
Savings Potential
Conventional garbage disposals can use a constant water flow of 2.0 to 15.0 gpm
when in use. This water use can be significantly reduced either by retrofitting with a
load sensor to regulate and reduce the amount of water used by the existing gar-
bage disposal during idle mode, or by replacing the garbage disposal with a food
pulper or food strainer. To estimate facility-specific water savings and payback, use
the following information.
Conventional Garbage Disposal Retrofit
Water use can be reduced by retrofitting an existing conventional garbage disposal
with a load sensor. Load sensors can reduce the flow rate through the garbage dispo-
sal to as little as 1.0 gpm when the garbage disposal is not in use (i.e., during idle peri-
ods). Water savings from the reduction in flow rate during idle use can be calculated.
East Bay Municipal Utility District. 2008.
WaterSmart Guidebook—A Water-Use Efficiency Plan Review Guide for New Businesses.
Pages FOOD9-11.