Introducing Rainwater harvesting systems
“Free Water” was unique to Ireland. Our European members have paid either a flat rate for water or according to what they have used. We were successful in resisting change for many years but as we all know that is coming to an end shortly with the introduction of Irish Water Utility.
The exact cost we will have to pay has yet to be announced. The price varies from country to country, but an initial annual cost of €150 - €200 wouldn’t be that un realistic. Water services cost €1.2 Bn in 2010, which translates to €154 per person.
In Ireland we use 145 litres per person per day and it is shown that where people have to pay for water the overall consumption decreases. Of the 145 litres we use is broken down to drinking water 3%; showering 32%; toilets 28%; washing machine 12%; sink/dishwasher22%;
A properly installed rainwater harvesting system in a domestic setting can be expected to reduce that water consumption by 45%. In a commercial/ industrial setting the water consumption can be reduced by between 75 – 85%. So what is Rainwater Harvesting and how does it work?
How it works:
Rain falls and is collected from your roof via your gullies and downpipes. Usually this would diverted to the waste water system.
This is the first cleaning step in the rainwater system – the filter. The rainwater flows from the roof to the filter. Here dirt particles and debris are separated from the water. The cleaned water flows to the tank. The dirt is washed to the sewer or soakaway with a small amount of rainwater.
2. Calmed Inlet
The clean water filtered is stored in either a GRP/ MDPE above or below ground tank. By using an underground tank, the water is stored in dark and cool conditions. The Calmed Inlet supplies the lower layer of the stored water with oxygenated water. This oxygen rich water prevents anaerobic reducing conditions forming in the storage tank keeping the stored water fresh. In an above ground unit water quality has to be monitored to ensure water purity. The HPS Group manufacture an insulated GRP tank which maintains water at a cooler temperature than a MSPE/ Plastic unit.
3. Overflow siphon
Any particles that are lighter than water (e.g. flower pollen, dust) float slowly to the water surface. All storage tanks have an overflow siphon, with a skimmer effect, removes this floating layer. The regular overflow from the storage tank is important to get the best water quality. It prevents souring of the water. The floating layer could otherwise prevent oxygen diffusion at the water surface, which could lead to anaerobic reducing conditions in the tank, and the onset of odour problems.
4. Floating pump intake
The pump intake floats suspended just below the water surface where the cleanest water lies. From this position the water is abstracted by the pump. A ball float, filled with air, suspends the intake valve, which has a further filter.
5. Submersible Pump
The Submersible pump can pump the water directly to the point of use, or pump up to a header tank in the attic. The pump will keep the pressure at 1 BAR and up to a maximum of 4 BAR. The pump will start operating automatically as the pressure in the line drops, ie. when a tap is turned on, then the pump will restore the pressure in the pipe. The pump will pump 20-80 litres/minute up to a maximum head of 30m.
6. Mains Top Up
The function of the mains top up is to allow mains water, where available, to top up the tank when the water level drops to a minimum level. The system will allow approximately 200 litres at a time into the tank until rainwater enters the tank again.
Get more information:
To hear more about rainwater harvesting and how it can help you reduce costs with the new water charges phone Gareth today on 021 4919545 or visit www.hpsgroup.ie