Africa Energy Indaba

Water Conservation

The beauty about water is that it can be recycled. The bigger picture reveals that as our populations grow and more and more people migrate to the cities, a bigger demand is place on water resources. Water is a finite resource; as a result it is set to become more expensive as demand grows.

Water Conservation At Your School

A school typically uses a lot of water which can be re-used if not contaminated or cleaned up for re-use through proper treatment. Water can also be conserve through the implementation of certain features and good management.

Think about it, implementing measures to conserve, re-use or recycle water waste at your school will not only save money, but it will make more water available to those people who desperately need it. The sooner your school starts living with the environment instead of on it, the better.

How Do We Conserve Water?

Become aware of what shower heads and taps are installed at your school. Low flow taps and low flow shower heads go a long way in saving water. Just by installing low flow showerheads can reduce water consumption by around 50-70%, bringing the shower flow down to 6-9 litres a minute from 15 litres, without compromising on water pressure for your users. For an average shower length of 8 minutes this can save 60 litres of water. Low-flow showerheads and taps are simple to install and very cost effective. The payback period for replacing all your schools showerheads with low flow versions is around 6 months or less depending on the cost of the shower head. The payback period for taps is considerably longer because less water passes through taps and the unit cost for taps is higher in comparison – but it’s still worth it. If your school has the budget, then you can look at movement sensors for your taps or flow stop systems. These types of taps will supply water on demand in a conservative way, just enough to do the job and then switch off.

Flushing Systems

Another way to conserve water is to check what flushing systems are installed in the toilets at your school.

Dual flush toilets reduce the volume of water been flushed – one push for liquids and another push for solids. Same goes for your schools urinary troughs, set the system so that one flush dispenses just the right amount water to do the job.

How Do We Recycle Water?

We generally use potable water (drinking water) from our taps to irrigate the schools grounds and garden areas. We also use portable water for general cleaning and flushing toilets. In order to reduce the use of potable water for these functions, we first need to identify what water can be recycled?

Harvesting Rain Water

Rain water that would normally run off your schools roof and down your drains can be harvested. Rain water costs nothing and can be used to flush toilets, irrigate the school grounds or it can be used for cleaning. The harvested water is typically captured from your schools roof drains, filtered if necessary and stored in a tank for on-demand use. It can also be fitted with a pump order to direct water via the plumbing or irrigation to a specific point of use.

The tank can surface mounted or installed underground. The system ensures an alternative water supply in the event of water restrictions or municipal water switch off. It is generally accepted that 1mm of rainfall over one square meter will give you 1 litre of rainwater – why not build a model to check if this is true?

Grey Water Systems

Grey water at your school can also be recycled. Grey water is water that has been used for cleaning. This includes human cleaning. So all the water that your school uses in the cloak rooms, specifically the basins, showers and baths (excluding the toilet waste water) can be recycle for re-use. Grey water also includes waste water from washing machines if you have a laundry at your school.

Care must also be taken to ensure that the recycled water does not contain harmful toxins that may present a health and safety risk to school goers. As such waste water from staff kitchens and canteens that contain fat deposits cannot be included in the grey water recycling system.

The recycling system is made up of one or more tanks that include a filtration system. A well designed piping system serviced by a pump will ensure that the system works economically. The filtered or treated water is then re-used for cleaning or irrigation. Depending on the type of system and the cost of water at your school, a payback period of two to three years is achievable – this means more money saved at your school.  Believe it or not the diluted residue soaps in the water can provide useful sulphates and nitrates which some experts say is more beneficial to the garden than clean tap water. Like rain water recycling systems, the storage tanks systems can be installed below or above ground. Unlike the rain water recycling systems, grey water systems requires maintenance and monitoring which includes periodic water quality testing.

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