Water Supply & Sewage Disposal
On 15 December 2011, Jo Osborn of South East Water gave a presentation on “The wonderful world of water”.
The presentation took us through a background to the company which supplies drinking water to 2.1 million consumers across from Kent, East and West Sussex, through to parts of Hants, Surrey and Berks, including Farnborough €“ an area covering 5,657 sq km
South East Water is the second largest water-only company in the UK and supplies 565 million litres of water each day, or 125 million gallons, through 14,500 km of mains.
In Farnborough most of the town is fed from a service reservoir (a bit like a giant covered swimming pool which stores treated water) at Crowthorne Reservoir which is between Camberley and Bracknell via large diameter trunk mains (typically 14”, 12” & 10” mains). Crowthorne Reservoir receives water from boreholes at Hurley, White Waltham and Beenhams (Maidenhead) via pumping stations. Water can also be fed into Crowthorne from the water treatment works at Bray which takes water from the River Thames and the gravel beds adjacent to the river.
The presentation explained about the water treatment processes, showing that groundwater sources need less treatment than river sources as the water is naturally filtered through the underground rocks.
While South East Water works hard to find new sources of water and to ensure there is enough water for our needs, it is also important we don’t waste water. In the South East we use an average of 160 litres per person each day, this was put into stark contrast with the developing world where many people use around 10 litres per person per day and have to walk many miles to get clean water for their families.
That is why it is important we take small steps to use water wisely. Some of the simple tips to follow at home and in the garden can be found at www.southeastwater.co.uk/waterefficiency.
2011 was one of the driest on record in the Sussex area and customers there are being asked to take particular care not to waste water as reservoirs refill over winter. While Farnborough itself is not at this stage affected it is important we also think about how we can use water wisely throughout the year.
Having a water meter fitted is one way to make sure customers pay fairly for the water they use, and encourages people to think about using water wisely. Find out more at www.makingeverydropcount.co.uk.
Finally South East Water reminded us of the simple three-point checklist when a caller claims to be from the “Water Board”. Unfortunately some bogus callers prey on vulnerable people and con their way into people’s homes €“ always be stranger aware.
Check their company photographic id card
Look for the South East Water logo on their uniform and van
If you are uncertain keep them out. Call the Bogus caller telephone line 0800 519 2222 to double check
Tracy Sacks of Thames Water described what happens to our waste water, explaining that Thames Water removes and treats 2,800million litres of sewage every day for 13.8 million people, and maintains and runs 43,500 miles of sewer, 349 sewage treatment works, 2,530 pumping stations and 1.2 million manholes. They are also the biggest generator of ‘green power’ inside the M25.
The sewage treatment process begins with screening to remove large debris, followed by primary settlement, when the solids that settle on the bottom (sludge) are drawn off. The liquid goes for biological treatment and a final settlement before discharge into a river, primarily the Thames. The sludge is allowed to thicken, then fed into an anaerobic digester. The material is then put into huge storage tanks, undergoes ‘dewatering’ and is then sold to farmers as a soil conditioner.
Tracy said that there are two things that householders can do to help these processes runs efficiently: flush nothing except lavatory paper down the loo and never put fat down the kitchen drain. Both cause blockages, (the fats, 50,000 every year) and add to the costs. Kitchen fats should be allowed to solidify, in the fridge if necessary, and disposed of in the wheelie bin.
Although Farnborough is not affected, Tracy also mentioned the Thames Tunnel, currently in its Phase 2 consultation period, needed for the 39 million tonnes of sewage discharged into the Thames annually. As little as 2mm of rain can now trigger a discharge, and tides mean that the sewage stays in the river for weeks.
Finally, Tracy spoke about Thames Water’s WaterAid, with its vision of a world where everyone has access to safe water and sanitation.