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by Jack Vivian, Ph.D

Water has always been the lifeblood of humankind and of mechanized industry. Its life sustaining qualities and ability to perform work and transfer thermal energy coupled with its abundance has helped facilitate the industrial revolution and our current way of life. Today, however, the culmination of several powerful forces are posing a serious challenge to our traditional way of life and the work practices of our businesses, and will become even more of a threat in the years ahead. Consider the following problems:

• The depletion of groundwater reserves.

• The rising costs of freshwater consumption and waste-water disposal. •

• The increasingly stringent mandates of environmental law.

• The rapid rise in the public awareness of the need for resource preservation and pollution control.

• The water and waste-water infrastructures in many cities are in need of repairs and major upgrades; the result is a need to spend billions of dollars in maintenance and new construction.

• The fact that state and federal governments are cutting back on funding of water and sewer projects; the cost of operating and maintaining those systems is being shifted to users in the form of rate increases.

In less than five years, public assembly facility managers in several parts of the country have seen water go from being a low-cost, limitless resource to one that is expensive and scarce. During this time, water prices have doubled or even tripled in many locations, even in areas not always associated with water supply problems. The price and availability of water are particular concerns in the water-strapped West, where expanding demands for water are pitting homeowners against agricultural and industrial interests. Unless users reduce demand for water through conservation efforts, economic development will suffer. These trends will cause the public assembly industry and others to give high priority to the development of economically viable water conservation programs.

If public assembly managers are to make a significant reduction in the water use in their facilities, they must combine use of new technologies and good operational practices in a comprehensive water conservation plan. Start with an examination of how water is used in the facility’s food and beverage, restrooms, locker rooms, cooling tower and ice resurfacing (if applicable) operations. Depending on the rate charged for water use, it may now be economically beneficial to upgrade fixtures solely for the purpose of reducing water use, such as:

• Install low-flow aerators or laminar flow restrictors in all faucets; better yet, replace with spring-loaded types that automatically shut off.

• Install showerheads that flow at no more than 2.5 gallons per minute.

• Install 1.6-gallon per flush toilets and 1.0- gallon per flush urinals. Reduce flows delivered by flush valves. On flush-ometer- type toilets, have a plumber inspect valves for reversible conserving rings or acceptability for other modifications to reduce flow. There are also some no-flush toilets on the market that may be worth investigating

Nearly every public assembly facility is air conditioned by some type of refrigeration system. All have either air-cooled, watercooled or a combination air and watercooled condenser. Cooling tower water requirements can be reduced by properly maintaining the drift, makeup water and bleed or blow-down systems. As air passes through cooling towers, a portion of the tower’s water becomes entrained as water droplets in the airflow are carried out of the tower—a water loss known as drift. A wellmaintained and properly operating tower will have drift losses in the range of 0.2 percent. New tower designs can reduce drift to as low as 0.1 percent. In contrast, a poorly operating tower can lose between 1-2 percent of the water flowing through it to drift.

Cooling tower makeup water systems are also notorious water wasters. As water flows from the grates at the top of the tower, over the piping and baffles, it evaporates or is picked up in the drift. This water has to be restored to the system and this is called the makeup water. It normally comes from the regular supply system with the amount controlled by a float valve. To reduce water losses due to malfunctioning makeup water valves, all cooling tower makeup water systems should be inspected for proper operation at least weekly when the water-cooling operations are required. A poorly functioning flow valve can provide too much water overflowing the basin of the tower and wasting water.

One or two percent may seem like a small amount of potential savings but when one considers that the average tower has a 3 gallon per minute (gpm) evaporation rate, 0.3 gpm drift and makeup of 4 gpm, this can be a significant amount over time. To estimate the average evaporative cooling tower water consumption amount, consider that the tower may run on water cooling mode only for 50 percent of the time (assuming that the fan mode can satisfy the heat transfer the other 50 percent of the time). This means that, for an average spring or summer day, the cooling tower system uses 2,880 (12 hours x 4 gpm x 60 min) gallons of water per day. Even a savings of two percent would result in a sizable reduction in water consumption. This is without calculating the bleed or blow- down that must occur to keep the tower from excessive scale.

Bleed or blow-down is a controlled water loss from the system so that the dissolved minerals present in all water, to some degree, do not accumulate in the cooling system. The amount of bleed required is highly dependent upon the quality of the makeup water, particularly the calcium concentration. Calcium carbonates deposit along tubing surfaces in heat exchangers or chillers, insulate the water from the pipe and diminish heat transfer from the water to the pipe. This causes compressors to run on higher head pressures, use more energy and results in more equipment wear. Keeping the tower scale at a minimum and controlling the amount and frequency of the bleed or blow-down are important steps to conserving water and energy.

Other suggestions for water conservation in the cooling tower operation:

• Maintain the cooling tower water treatment system.

• Prepare performance specifications for chemical service vendors. Require proposals with projections of water consumption and chemical use. Many providers will give glowing reports on the chemical side but neglect to inform the user how much water is consumed to reach the desired results.

• Control cooling tower bleed-off based on conductivity by allowing bleed-off within a high and narrow conductivity range — this will achieve high cycles of concentration in the cooling system and reduce water use in the cooling tower.

• Inspect drift losses — if excessive, install drift eliminators or repair existing equipment; achieve at least five cycles of concentration or the maximum number of cycles achievable without scale formation — implement measures to remove or compensate for minerals which may form scale.

For arenas with ice operations, water used for ice resurfacing can amount to more than 10 to 15 percent of the total consumption for a facility. For a typical arena where the public rents ice with normal usage on weekdays and early morning to late evening on weekends, below is a rough calculation of the water used:

Mon-Fri, 5 pm to 11 pm:
10 resurfaces @ 60 gal = 600 gal/day

Sat-Sun, 6 am to 12 pm: 1
8 resurfaces @ 60 gal = 1080 gal/ day

Total estimated water consumption for ice resurfacing = 5,160 gal/ week.

Ways to conserve on ice resurfacing water:

• Use the fill gauge on the side of the resurfacer to only put in the quantity of water needed to resurface the ice properly. Water left in the tank will not be of proper temperature for the next resurface so to overfill would be a waste of heated water and results in the next ice surface being of lesser quality.

• Check the fill hoses to be sure they are shut off after each filling. Don’t allow the resurfacer tank to overflow during filling, as the tank will hold 85 gallons and only 50 to 60 gallons are required for a normal resurface.

• Don’t use water to melt the shavings on the top of the melting pit. A heat coil system using waste heat from the compressors should be able to melt the shavings. Have the operator shovel or alter the grate system so water is not needed in this process.

Water conservation in business is a relatively new topic. Efficient water management for public assembly facilities is analogous to energy conservation in the early 1970s. Its effectiveness will increase as new applications of water conservation measures evolve. Below are several initiatives management can start now to be ready for the crisis ahead:

• Conduct a water audit to assess current water uses.

• Ask your water and waste utilities for projections of future rates. Learn as much as possible concerning the methods used to calculate rates and the nature of the water problem in your area.

• Investigate capturing runoff or rainwater from the arena’s roof structure and storing it in retention ponds or cisterns such as those used years ago on farms before commercial water systems were in place.

• Look into using water from on-site retention ponds or nearby lakes for makeup water for the cooling tower and air handlers.

• Investigate the potential for converting or adding more air-cooled capacity for HVAC and ice making purposes. Have the manufacturers calculate the savings and amount of payback, if any (the electrical costs may offset the savings).

• Install a water meter on the cooling tower supply line to measure consumption. Many municipalities are discounting the water and sewage rates if the arena can prove the evaporation rates and the bleed water is being discharged into the storm sewer and does not have to be treated by the sewage plant. The sewage rate is normally calculated from the amount of water consumed, assuming that this water is returned to the sewage plant to be treated. If that is not the case then the rates can be adjusted.

Well-planned water management is often accompanied by savings of energy and wastewater treatment. These long-term savings can reduce expenses and sustain the viability of the public assembly business. Managers with a thorough knowledge of their site’s water use will be better able to lessen the impact of future water shortages on their operations. They will also be better informed and able to converse intelligently with conservation officials and better represent the industry when the time for conservation comes.

Jack Vivian, Ph.D, is the director of the Ice Arena Institute of Management, Member of the Board and Instructor at the IAAM- PAFMS at Oglebay and CEO of JRV Management Inc, a Michigan and Ohiobased management company. He may be contacted at jvivian@jrvmanagement.com.

© 2004-2005 International Association of Assembly Managers
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