What’s Watt #1

Graham Jones, Sales Director, South Africa

08 September 2017

“The World Economic Forum’s ‘2015 Global Risk Report’ has named water crises the world’s greatest risk. The world is forecast to face a 40% shortfall in water supplies in 15 years, owing to population growth, urbanisation and increased demand for food production, energy, and industry. Climate change also increases water-related risks.

Ranked among the world’s 30 driest countries, South Africa is facing serious water challenges. Water infrastructure is ageing, technical skills are in short supply and demand patterns are shifting, while changing rainfall patterns are leading to inadequate supply in several areas. Vandalism and theft of public infrastructure, the nonpayment of bills, wastage through a lack of maintenance, poor water services planning and prioritisation at many municipalities, as well as increasing pollution, are further impacting on water supply.”

Extract from Creamer Media – November 2015

For many years we have seen a crisis in clean water supply developing. This, coupled with recent draught conditions, make it abundantly clear that water supply reliability may well follow power supply reliability.

Again, South Africans will need to provide for the protection of this basic but absolutely key resource. While inconvenient and perhaps a little funny to have to shower at the gym because water has been interrupted for a day, the longer term prospect of being without flushing toilets and safe drinking water is serious.

Daily GreenHouse is receiving requests regarding water security systems as the realization of the effect of water interruptions dawns.

Similar to the power equation solution, water systems also have the following considerations:

1 Usage determines what is reasonable in terms of backup and what should be sought in terms of collection. The greater the usage, the larger the backup reserve my need to be. Please do note that irrigation should be considered separately from domestic water supply given the large volumes required for irrigation.
We have been asked to reduce water usage by refraining from garden watering, Pool filling etc. There are always ways of doing things smarter – like taking showers (rather than baths) and shorter showers – using low flow shower-heads and ensuring full washing loads, but we will always need a certain, essential amount of water every day.

2 Backup systems bridge those times where municipal water is not available. They use municipal water to fill up reservoir tanks which, when called upon, deliver water through pressurizing pumps to the home.
Installed correctly this system provides pressurised water on demand without loss of water back to the municipal grid and at adequate flow rates demanded by the user.

3 Collection of rain water can be interfaced with the backup system. Given appropriate capacity, pressurisation and filtration one can get off the water supply grid – the same as with power. It is always good to know that the municipal water feed is there as a backup to one’s own supply.

A quick calculation:
Centurion experiences and average of 550mm of rain per year.*
For each 100m2 of roof area in our collection system, 10mm of rain will yield 1000L = 1 m3 = 1 ton of water
So each 100m2 of roof we harvest rain water from could yield 55,000L per year!
That is 55 tonnes of water – no wonder the Gauls were afraid of the sky falling on their heads!

Our rain water is relatively clean, and by removing large particle debris then filtering the water appropriately, rain water can be absolutely potable.

4 Filtration of home water, whether from rain collection or municipal feed is important and absolutely affordable and achievable. With recent reports of the quality of Pretoria’s water supply – I, for one, will be fitting a filter system in the near future to augment my water security system.

We can become self-sufficient in terms of supply and quality of water.

* Average rainfall figure reports vary – this figure taken from www.saexplorer.co.za

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