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Describe the role process water plays in industrial processes/applications.

Solution. Process industries rank above all others as users of water. No process plant could operate without water as a cooling medium and as a direct raw material in certain phases of a process. The local water supply, therefore, must be studied before an area can even be considered as a possible site for a processing facility. A detailed estimate of present and future water requirements must precede a plant siting study. Then the availability of water in the region being considered should be carefully investigated. If well water is to be used, a complete study of the history of the groundwater table is necessary. If groundwater supplies are adequate, they are preferred because of their lower temperature and generally higher water quality as compared to surface water sources.

Surface waters from streams or lakes also require careful consideration since both their quantity and quality can vary greatly on a seasonal basis. Streams discharging into the ocean during times of low runoff can become saline as a result of seawater intrusion. Under such conditions, plant design may have to include large storage facilities for fresh water to be collected during periods of high runoff and used during dry seasons when the stream becomes saline.

Companies moving into relatively nonindustrialized areas often fail to consider the possibility of other plants following suit. The availability of the water supply should be adequate not only for the future needs of the proposed plant but also for the anticipated needs of other industries that might move into the area. It is also desirable to consider alternate sources of supply that may be required if the preferred water source becomes depleted. Water quality must be studied as well as water quantity. Chemical and bacteriological examination will indicate the extent of treatment required and can aid in the development of water cost figures for comparison with other locations. The possible contamination of the water source by other industries in the area should be anticipated. Note that “contamination” may consist of raising the temperature of the water to a level that renders its use as a cooling medium impossible.