Environmental Engineering Reference
In-Depth Information
4.
Utility water for cooling towers, boilers, and scrubbers; ice making; in water lubricated
bearings; for general use in processing and administrative buildings—including fire
systems, hand washing, drinking, and toilets—and for landscape watering.
Strategies for water reduction
Food-processing facilities are different by nature so water reduction programs are specific for
each industry and location. However, there are five general strategies that can be followed to
minimize the impact of water consumption in most food-processing plants:
1.
Minimize consumption by adjusting processes and equipment.
2.
Replace processes with alternatives that consume less water or no water.
3.
Reuse water in the same process.
4.
Recycle water and use in other processes.
5.
Replenish water by implementing mitigation projects.
Minimizing consumption
The successful implementation of any water conservation program will depend not only
on technical approaches but also on effective personnel training. Processing plant employ-
ees have the main concern of keeping up with production, so certain practices are per-
petuated not because they are the most efficient but because they have been in place for a
long time.
Besides employee training, it is essential the identification and quantification of water use
by individual processes. The installation of water meters in individual equipment will not only
pin down operations with high water consumption but will also help to monitor progress.
But before even installing water meters, fixing leaks is a must.
The most important strategies for water reduction will be presented in the following
sections.
Excessive pressure
One of the causes of water waste in processing plants is excessive pressure. The volumetric
flow of water in a nozzle is proportional to the square root of the pressure differential, so by
decreasing the pressure, the flow can be reduced. In many situations, high volumetric flows
are needed in just a few applications in the plant, and the pressure of the water distribution
system is kept high just to satisfy those few situations. This not only places high strain on
value seats and joints but on waste water. A better practice is to reduce the overall water pres-
sure and use booster pumps in places where needed. Another alternative is to install pressure
regulators in equipment that do not need high flow rates.
Inadequate nozzles
Hoses are common in processing plants to wash floors, equipment, or wash down material to
the drain (a practice that is not encouraged). Installing water-saver nozzles that shut off when
the lever is released will help to eliminate water waste.
In spray-washing equipment, retrofitting with high-pressure low-volume nozzles is a good
water-saving strategy. When nozzles are used to spray water on the food product, selection of
optimal spraying heads that provide the right pattern and flow will contribute significantly to
