As I write this, I am amazed at how nature is distributing water around the world
+ Western Europe has just been hit with a very large snowfall that has crippled aviation and transportation
+ At various times in December, parts of North America also received very large snowfalls, and aviation and transportation has also been crippled
+ The northeast of Australia is receiving record floods
+ The west of Australia is having both record floods (northern portion) and drought (southern portion)
Nature has a way of distributing water very inefficiently and badly. Many places do not have enough water, while others have too much. And a place that has too much water often has water that is not suitable for use. I am reminded of the epic poem by the English poet Samuel Taylor Coleridge … The Rime of the Ancient Mariner, and the classic line
“Water, water, everywhere, And all the boards did shrink;
Water, water, everywhere, Nor any drop to drink”.
When we have too much water, we often have flooding, disease, etc, as the water is not suitable for use.
And … often water in industrial processes, is an undesirable by-product. In industries ranging from food processing to coal mining to oil and gas processing, water is not desired. Wastewater is a disposal issue, not a resource.
Which leads me to ask the question … did you know we are now half-way through the UN International Decade for Action ‘Water for Life’? The decade runs from 2005 to 2015.
And this leads me to ask another question … “what purity of water is required?” This is a very different question from the one that is normally asked, which is “what water purities are available?” And I am surprised at the complexity of the question. Let’s consider something very basic, like a home. What purity of water is required for a home?
Let me reword the key question … maybe the question should be worded … “what is the most contaminated water that can be used for this application?”
For drinking and food preparation, we require a very high purity.
For rinsing, we require a lower purity than for drinking and food preparation … we can tolerate a higher salt content. It is quite feasible to rinse in clean seawater – many beaches have showers for the swimmers, which uses seawater – and there are no harmful side effects. Note … I am separating rinsing from washing as they are two very different activities.
We require a different purity for washing. If you have ever washed greasy pots, you have seen first hand that wash water does not need to be “clean”.
We require a different water purity for household plants. This water does not need to be clear – it can have colour.
And there are more depending upon the uses of the home.
But the key is the question, what is the most CONTAMINATED water that can be used for THIS application? This is a very difficult question to answer, but is paramount to reducing water costs. Consider the following:
+ “Normal” contaminants are TDS, TSS, colour, oil and grease, etc. All of these are issues for drinking water, but generally, these are not an issue for water that is used for pump seals
+ Cooling water has different requirements for material selection, legionella, corrosion management, etc, but for thermal purposes, almost any water can be used
+ In extreme circumstances, almost any water can be used for fire water. Seawater and steam condensate return are two diverse examples of water that can work well in fire fighting applications. It should be noted that both will have vastly different material selection and human handling requirements, but both will extinguish many fires.
Water for drinking is becoming more expensive for all – partly because we are using drinking quality water for industrial applications. The key to reducing water costs lies in answering the very difficult question … what is the most contaminated water we can use for this application.