Water Management Considerations for Factories

Despite increasing scarcity, water is still a relatively cheap commodity and this is perhaps why, except for the most water-intensive industrial sub-sectors, water is often not given the priority it deserves. Certainly in my semi-arid home country of South Africa, while increases in water prices have outstripped increases in energy prices, water prices have not kept pace with the true value of water as a diminishing resource.

Despite the lack of economic incentive, forward-thinking organisations place water security (not just for themselves but also for other water users) at the heart of sustainability strategy in recognition of the increasing water-related risks businesses and society face.

Manufacturing processes tend to have fundamental impacts on water resources. The first of these is on the quantity of water used or abstracted. Clearly the less water that can be used to produce a unit of product, the lower the costs for the factory and the more water that remains for the use of others in the catchment. The two major strategies available to reduce this use are to minimise the amount of water used at the point of each individual use, and to recycle as much water as possible. Recycling can be carried out with or without treatment, depending on the application.

The second major impact manufacturers have on water resources is on water quality. Water quality impacts occur as the result of effluent discharge, aerial deposition of contaminants, seepage into groundwater and surface water and from contaminated runoff. The results can range from unnoticeable to catastrophic, and it is vital for factories to have an understanding of the nature and quantity of the contaminants they release into the environment. The best way to minimise water quality impacts is to deal with them at their source, and often this has positive consequences for other sustainability objectives, such as resource efficiency for example. In many cases it is however impossible to limit pollution to acceptable levels by this approach alone, and this is when end-of-pipe solutions may have to be found. These generally produce some form of concentrated waste which then has to be safely disposed of, so be aware that effluent treatment does not necessarily make the problem disappear.

It is true that the industry in which you operate will have much to do with the focus and importance placed on water management issues. Integrated pulp and paper mills are water intensive and also have potentially significant water quality impacts, so this is an example of a sub-sector where water management receives high priority. The electroplating and drum reconditioning industries are examples of industries with low water intensity, but which can have serious water quality impacts. So some industries are well known for their water management issues, and in sophisticated countries, most of these industries tend to be heavily regulated, not only in terms of water-related benchmarks but even in terms of technology. In emerging economies the onus falls on senior management to demonstrate a commitment to sustainability, and here risk assessment is a vital tool to guide policy and decision-making.

Water management in industrial organisations cannot be considered in isolation from other important sustainability and operational goals. Energy and water are often closely linked. For example, the use of cooling towers for the rejection of heat to the environment relies on the evaporation of water. Approaches such as process integration can assist with energy recovery and reduce cooling tower evaporation. Water is also often closely tied to material usage. For example, water may be used to displace valuable product from pipelines, or to leach valuable soluble materials from solids. Water conservation and water quality management in the industrial setting is therefore a matter of trade-offs, and requires an intimate knowledge of production processes. Often water use impinges on energy consumption, product quality, material usage and throughput in a production plant. Issues of water management in factories return us to that enduring theme of having to take a systems approach in our dealings with issues of sustainability.

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