Turn over every drop before it’s used – Practical processes can save water
by Ruth Smith – Senior Design Manager
Before we spend money on any project, we turn the decision over in our mind to confirm that we will be getting the best value for money. There are many substitutes for money, but none for water. Surely our water usage decisions need more attention.
The World Health Organization (WHO) predicts that by 2025 half of the world’s population will be living in water stressed areas. That’s a scary thought! Most industrial companies have water usage goals, you only have to look on the web for these. Can we, as operational and design engineers, make a practical impact in this important area?
I would like to make three suggestions:
– We can start by checking our incoming water analysis. Water quality can change from time to time due to changes in municipal sources, seasonality, and the like. Check that the water treatment plant settings on chemical dosing and turbidity, for example, are set up for the current parameters. Then confirm that the water treatment plant and distribution system is (are?) operating according to the design parameters., It is often the case that filters are back-washing more frequently due to sand, carbon or membranes that have not been properly inspected and maintained for some time.
We can evaluate our current water standards and specifications and seriously ask ourselves whether we are over-treating some water streams. Obviously, product water is important and should be of the highest quality in food, beverage and pharmaceutical production. But what about water used for area cleaning, cooling, dust suppression and irrigation? If your specifications been in place for some time, they might need a review. Every time we treat water, we use equipment, chemicals, and energy, and we lose valuable water in the treatment process. Making sure that our treatment regimes fit the water use could save scarce drops.
– We can examine our cleaning processes and, in particular, our cleaning agents. Approximately one third of all Quaternary Ammonium Compounds (QACs), commonly used industrial detergents and disinfectants, end up in the environment. The use of Nitrates and Phosphates in cleaning regimes also requires further downstream treatment or concessions to discharge. This should be a signal to partner more closely with our cleaning chemical suppliers to find alternatives, or at least reduce our reliance on these thirsty chemicals. These chemical loads negatively impact on our ability to treat and reuse water now or in the future.
As process engineers, our minds should be swishing and sloshing, turning over every drop before we use it.