Cement, Energy and Environment

, I How Does A Water Audi t Work? Water has long been the forgotten utility. It was inexpensive. It was perceived to be plentiful and there were few incentives for conservation . No more. Population growth, economic development, aging infrastructures and ongoing regional droughts are causing trouble for municipal water systems that are trying to keep up with rising demand. Facility executives are facing rapidly ri sing rates, water use restrictions or both. Some water utilities are implementing maximum water-use levels, with economic penalties should a facility exceed the limit. The challenge for facility executives is to find ways to reduce water use without interfering with facility operations. The good news is those facilities that have implemented a comprehensive water conservation programme have found that the return on investment is becoming easier to justify. To achieve savings, what is needed is a programme designed to address all aspects of water use within a facility. Thirty years ago, when energy conservation became an important issue, many facil ity executives responded by turning down thermostats and removing fluorescent lamps . And while these strategies did produce some savings, they did not fully address the issue of energy conservation . Areas with even greater energy saving potential went unaddressed simply because they were overlooked or not fully understood. To produce more savings than could be achieved through quick cutbacks, facility executives turned to the energy audit. The energy audit proved to be the most effective tool in helping manage energy use. An energy audit helps faci lity executives identify and quantify what steps can be taken to reduce energy use. But even more importantly, it gives facility executives a detailed survey and analysis of how energy is used within their facilities. The same process is needed today to reduce water use. Water Use Audits Water use aud its, like their energy counterparts, are an important first step toward understanding both a faci lity's water use and what can be done to reduce it. They trace water use from its point of entry into the faci lity through its discharge into the sew~r.. They identify each point of water use w1th1n. and around the facility and estimate the quantity of water used at each of these points. They identify and quantify unaccountable water losses and possible leaks. They provide facili ty executives with a road map of potential savings. as well as implementation costs. In addition to water. quantity, water use audits should also take into consideration water quality. Some of the largest potential savings that can be achieved is through the recycling of water or the use of rain water. Water audits can help identify potential uses for alternative sources of water. A comprehensive water use audit will examine all of the major areas in which a facility uses water, including sanitation, maintenance, mechan ical systems, building processes and irrigation. For each of those areas the water use audit will provide a breakdown of the how, when and where of water use. Steps in a Water Audit Step 1: The Wa ter Use Inventory It is important that facility executives develop an understanding of exactly how and where their facility uses water. To do this, an inventory of all water use points in the facility with flow rates must be developed. Start with a walk through of the facility, identifying every point in which water is used. For items such as toilets and faucets, the inventory should include the item, its location and its flow rate. If the facility has low-flow fixtures or if flow restrictors have been installed, identify them on the inventory. Don't overlook building mechanical systems. Mechanical systems account for approximately 25 percent of the total water use in an average building. For example, cooling towers and boilers are large users of water. Both systems require that a certain quantity of water be bled off and replaced in order to control the level of solids suspended in the circulating water or steam. Check the blow down system for cooling towers and boilers to determine the rate at which make up water is being added. Refrigeration units that use once-through cool ing systems also can be very large users of water. The inventory should include the type of system installed, its location, its capacity, and the rate at which it uses water for cooling. In some cases, the owner's manual wil l identify the