WaterSense at Work: Best Management Practices for Commercial and Institutional Facilities
Vivarium Washing and Watering
Vivariums, or animal research laboratories, utilize water-using equipment for clean-
ing and animal watering purposes. This equipment includes cage, rack, bottle, and
tunnel washers and automatic animal watering systems. Washers can use large
volumes of water based on the number of rinse cycles and water used during each
cycle. Animal watering systems can use large volumes of water if constant flows or
frequent flushing is required.
Cage, Rack, Bottle, and Tunnel Washers
Cage, rack, and bottle washers are batch-type washers that are front-loaded with
washer racks. Traditional cage-and-rack washers are programmed with a pre-rinse,
wash, and final rinse cycle. During each cycle, the unit can use between 40 and 60
gallons of hot water. In addition, many washers have optional cold-water tempering
systems that cool the wastewater from each cycle to ensure that the discharge water
temperature does not exceed sanitary sewer requirements. Accounting for water use
in all cycles, traditional cage-and-rack washers can use as much as 320 to 480 gallons
of water per load.
More recent models of cage-and-rack washers use less water per
cycle and allow users to choose the number of rinse cycles to minimize total water
use. Some units also allow water from the final rinse cycle to be reused in the next
cycle. More recent units can use less than 50 gallons per cycle, and some use as little
as 12 gallons per cycle.
Tunnel washers are conveyor-type washers that are capable of cleaning a number of
cages, racks, and other laboratory accessories at once. Tunnel washers are typically
found only in very high throughput vivarium operations. There are four main cycles
in the tunnel washer: pre-rinse, wash, first rinse, and final rinse. The final rinse uses
only fresh water, while the other cycles can use water recycled from the wash, first
rinse, or final rinse. Starting with the final rinse cycle, water moves countercurrent
within the tunnel washer and is disposed of after the pre-rinse cycle. Because tunnel
washers are designed for high throughput, they are not necessarily more efficient
than batch-type washers for smaller operations.
Animal Watering Systems
Automatic animal watering systems provide drinking water to laboratory animals.
These systems are used instead of manually filling bottles. There are two types of ani-
mal watering equipment, which differ in their method of bacterial buildup prevention:
flushing animal watering systems and recirculating animal watering systems. Flush-
ing animal watering systems use a periodic, high-pressure flow to “flush” and remove
bacteria from piping. Residual chlorination is typically used to further control bacterial
growth. To control bacteria, recirculating animal watering systems use a constant flow
of water treated with ultraviolet disinfection or other methods before distribution for
Beckinghausen, David. October 1, 2006. “Energy-Efficient Washing Systems.”