Prepared by:
Roy E. Carawan
Extension Food Science Specialist
Consulting Technical Writer: Teri Houck
Graphic Artist: Karl E. Larson
Publication Number: CD-41
Last Electronic Revision: March 1996 (JWM)
Most bakeries use 10,000 to 300,000 gallons of water per day for washing and sanitation purposes or as an ingredient (in dough, toppings, fillings, etc.). As much as 70 percent of this water is discharged daily as wastewater to the public sewer system. Pretreatment regulations are becoming increasingly stringent and the costs of water and wastewater treatment are rising. As a result, many bakeries are looking at water conservation as a practical way to save money and in-crease profits. This publication shows how cutting water usage in your plant can save money and also provides management tips for conserving water in bakeries.
Water quality is very important in food processing. Organic and inorganic impurities, as well as bacterial content, must be controlled. Chlorine and other water contaminants are known to adversely impact the processes in bakeries.
In fact, all water that is used in the final preparation of foods intended for human consumption must be potable water.
In the future, government regulations may require bakeries to treat their incoming water to assure the production of quality products. Because of the low quality of some water, bakeries may need to treat their water now. Even today some wastewater discharge permits for bakeries require treatment of incoming water before it can be discharged. Such water treatment processes include:
These processes will be expensive. By saving water now, you can cut costs if you need to purchase and operate these systems in the future.
Water Use in Bakeries
An enormous amount of water is used to prepare a product before it reaches a food processing plant. The agricultural production of eggs, milk, and flour use biological processes that require large amounts of water. For instance, some 1,150 gallons of water may be necessary to produce the wheat needed to produce one loaf of bread. This rate of water usage makes it even more important to conserve water resources wherever possible in the food processing stage.
Bakeries traditionally use 1 to 1.5 gallons of water to produce 1 pound of muffins, cakes, or danish or 0.2 gallon of water per loaf of bread.
Water cost for bakers has not been a major concern in the past. Even today most plants pay less than $2.00 per thousand gallons of water used. However, bakery managers should remember that water used and discharged must be treated. Sewer costs range from $2.00 to $8.00 per thousand gallons. Some bakeries use more than 250,000 gallons of water per day. Water and sewer costs for such a plant could approach $200,000 annually.
Furthermore, many bakeries are now paying surcharges or are required to pretreat their wastewater. Pretreatment systems can cost millions of dollars to install and hundreds of thousands of dollars to operate each year.
Cutting water use has a double benefit: it not only lowers the plant's water bill, it can also help to cut sewer charges because most municipalities compute those charges as a percentage of the metered water usage. In addition, reducing water use will reduce sewer surcharges if the waste concentration does not increase proportionately.
Using water more efficiently can help to counter increases in costs for water and pretreatment. Realizing the potential for savings, some plant managers have cut their plant's water use by 50 percent.
Water is a limited resource - another good reason to reduce water use. Only 6 percent of our rainwater is usable. The rest is lost to evaporation (70 percent) and runoff (24 percent). Of the usable water; industry uses 3 percent, agriculture uses 2.5 percent, and municipalities use 0.5 percent. Industries within municipalities may account for almost 50 percent of the municipal use.
Reports indicate that 25 percent of the nation's groundwater is being used faster than it is being replaced. In addition, groundwater supplies are threatened by leaking landfills, leaking underground tanks, pesticides, and fertilizers.
Cutting costs is not the only reason to take water conservation seriously. Some bakeries are located in communities without an abundant water supply. Because it takes large amounts of water to process bakery products, a plant can have a major effect on the local water supply even under the best of circumstances. During a drought the impact can be disastrous.
While California is noted for its water shortages, all states have experienced some level of drought. In 1986, for example, the southeastern states were stricken by the worst drought in nearly a century. Had the situation worsened, bakeries would have faced water limitations, production cutbacks, and even temporary plant closures. By reducing water consumption now, processors can increase their chances of getting through the next drought without having to curtail operations.
How much could a bakery save by reducing its water use to 0.1 gallon of water per pound? To find out, let's consider two plants that each process 250,000 pounds of bakery products per day. Each pays a total of $2.90 per thousand gallons for water and sewer services. However, plant A uses 0.1 gallon of water per pound of products processed while plant B uses 1 gallon.
Water and sewer costs for the two plants are shown in Table 1. Because plant A uses 0.9 gallon of water per pound of products less than plant B - a savings of 225,000 gallons per day - its operators can put $653 more in the bank each day. In effect, processor B is pouring that amount of money down the drain.
If you know your local water and sewer charges, the amount of water used in your plant to process a case of product, and your plant's daily production, you can use the worksheet in Table 2 to estimate the amount you would save by reducing water usage to a target value you select.
There are a few studies on bakeries showing how much water use can be reduced. You can set a goal of reducing your water use by 50 percent. Challenge and encourage your employees to reach this goal in your plant. Consider the priority steps given in Table 3 to establish an effective program. It will be helpful to establish a reward and personal recognition program for employees who contribute significantly to water conservation. The establishment of work teams to help conserve water in bakeries has also been shown to be very successful. Some helpful ideas for saving water in your bakery are given in Table 4.
Managers set the pace for water reduction. Your interest and involvement will let everyone in the plant know that reducing water use is important. There's no better time than now to take a close look at your plant and encourage your employees to work with you in conserving water and cutting waste.
Current Target Enter current and target water usage per case (gallons) Enter number of cases processed per day Multiply current and target water use values by daily production to determine daily water use Divide gallons of daily water use by 1,000 to determine daily water use in thousands of gallons Enter your combined water and sewer cost per thousand gallons: $ Multiply your daily water use (in thousands of gallons) by your water and sewer cost to determine your daily cost Enter the number of days your plant operates each year: Multiply the daily water and sewer cost by the number of days your plant operates each year to determine your annual water and sewer cost Subtract the annual cost for your target from the current cost to determine your potential annual savings. Equals: $ ___________