Today – 22 March 2016 – is World Water Day.
World Water Day is an international observance and an opportunity to learn more about water related issues, be inspired to tell others and take action to make a difference. World Water Day dates back to the 1992 United Nations Conference on Environment and Development where an international observance for water was recommended. The United Nations General Assembly responded by designating 22 March 1993 as the first World Water Day. It has been held annually since then. (UN Water)
Here in the UK we’ve seen a lot of water over the winter. According to our rain gauge, we only had a single day without rain in November and December combined. More recently it has been much drier, but the ground is still quite soggy in places. Even so, we have continued with our water-saving activities.
From a purely financial perspective, this is sensible: our water is metered and we pay for what we use, so the less water that comes into our house from the mains, then smaller our bill. But this isn’t really our main incentive. There are several reasons we like to collect and use our rainwater, one of which is brand new this year, namely the acquisition of our insectivorous plants. Our little carnivores like their water as unprocessed as possible, and so we collect it in a water butt just outside the limery and use a ceramic jug to transport it direct to them. The Venus fly trap is certainly thriving on this treatment.
But that’s only a tiny reason – the main point is that processing water takes energy. Water does not come direct to you from a reservoir – it passes through a treatment plant before being delivered to your house via the water mains. This is what Welsh Water describe as the stages in treating water:
Screening – this is the first step in the treatment process where mechanical screens
remove some of the larger debris that can be found in rivers and reservoirs ie floating
material such as branches, twigs, leaves etc.
Clarification – a treatment chemical (coagulant) is added to the water which causes
smaller particles that remain from the screening process to cling together. This process is called coagulation. These particles build into larger clumps which then are easier to remove by allowing them to settle and fall to the bottom of the tank leaving cleaner water above.
Filtration – This is, in effect, an attempt to recreate nature’s own purification process.
The water is percolated down through a series of filters made up of a layer of fine sand and supported on layers of coarse sand and gravel. As the water passes through the filters, any remaining material is retained and the clear, filtered water is collected at the bottom. The filters are regularly cleaned and the resulting sludge which has collected is removed for disposal.
pH adjustment – sometimes it may be necessary to add chemicals to adjust the pH of
the water. Chemicals are added to correct the pH value and maintain consistent quality.
Disinfection – finally, the water must be disinfected to kill any remaining bacteria. This is usually done by adding chlorine or sodium hypochlorite and occasionally ozone. (from Water in Wales)
So all these things happen before we even see our water out of the tap*. And every step in the process requires energy and resources.
But why put water through all this if we just want to use it to flush the toilet or water our plants? There is simply no need to filter and add chemicals to water for many of the purposes that we put it to. And so, Chez Snail, we flush the toilet with rainwater. We also use rainwater for tasks such as washing plant pots, sluicing away dirt and cleaning the chicken house. In addition, when the limery was built, most of the concrete was mixed using rainwater.
Just because we live in a place with plenty of water does not mean we should be profligate with it – especially when it’s been through so much to get to us. So, we shall continue to use raw water as much as possible and minimise our use of tap water… saving money and doing another little thing to help save the planet.
* Just in case you are wondering, Welsh Water does not add fluoride to any of the water that it supplies.