Water firm uses bacteria to iron out impurities
The bacteria absorb iron in order to survive and grow. In so doing they reduce the iron concentration in water a hundredfold, from 2 micrograms per litre down to 0.02 micrograms. The EC standard is 0.2 micrograms.
The bacteria have been in service at the Roydon treatment works in Essex since February. It uses water with a high iron level from an underground supply and serves 140,000 people in Harlow and the north-eastern edge of London. Its quality compliance manager, Ian Watson, said yesterday that in their first six months, the microbes had performed reliably. The bacteria grow in sand filters through which the water trickles. When their population reaches a high level the flow of water is temporarily reversed, washing out most of them. These are then removed; meanwhile the few remaining microbes stuck on grains of sand in the filter begin to multiply again.
Iron can also be removed by using chlorine or bubbling large quantities of air through the water. But when Three Valleys came to refurbish its ageing Roydon works, bacteria were chosen because it estimated they were the cheapest option.
Some chlorine is still added during treatment to kill bacteria which, unlike the iron-absorbing types, can infect humans.
Three Valleys is owned by the French company Generale des Eaux, along with several other smaller UK water companies. Bacterial removal of iron is already used in France but is new in Britain.
A water company is to give its three million consumers a say in the level of their bills. Welsh Water yesterday became the first of the big 10 water concerns to produce an annual report for its customers after criticism of the latest round of increased charges.
It will spend pounds 1m - 0.5 per cent of its annual operating costs - to find out the customers' views on its investment programme.
Britain's top vet sparks controversy with call for ban on slashing animals' throats in 'ritual' slaughters for halal and kosher meat products
Exclusive: Impact of immigrants on British workers ‘negligible’
Katie Hopkins continues campaign to become Britain's most hated talking head with poorly timed Bob Crow tweet
Ukraine crisis: Russia pledges to 'retaliate against sanctions' as Ukrainian president says Crimea vote will not be recognised
The quiet diplomat: Catherine Ashton - recognised and admired in all the world’s troubled countries, yet ridiculed at home
Grace Dent: Who cares if she spells it Barraco Barner? Gemma Worrall is more employable than some bookish arts graduate
- 1 Bad cattitude: Family call police after crazed and 'hostile cat with a history of violence' attacks baby before attempting to 'flee custody'
- 2 Family forced to flee home after discovering 'terrifying' nest of spiders in bananas
- 3 First Kiss: Filmmaker gets 20 strangers to make out on YouTube with awkward results
- 4 Grace Dent: Who cares if she spells it Barraco Barner? Gemma Worrall is more employable than some bookish arts graduate
- 5 Bob Crow death: 'Admired by his members, feared by employers' - Tributes pour in for RMT union leader and 'working class hero' Bob Crow
£20000 - £25000 per annum: Inspiring Interns: One of the largest mobile advert...
£20000 - £23000 per annum: Inspiring Interns: Our client specialises in creati...
£30000 - £50000 per annum + Very Competitive Salary: Austen Lloyd: Private Cli...
£30000 - £35000 per annum + Very Competitive Salary: Austen Lloyd: Residential...