Water In, Water Out
Safe Clean Water‚ Past & Present
In many countries, people are amazed to find out that all the water that comes into our houses, including the water we use for flushing the loo, is drinking water standard.
Anglian Water makes sure that its water is completely safe to drink and use by taking samples of water every day from customers’ homes, water treatment works, reservoirs and water towers.
Over 1.3 million tests on water are carried out each year.
In 1854 a London doctor, John Snow, suspected that an outbreak of cholera in London was linked to polluted water. His investigation led him to a water pump which was connected to a well in Broad Street which was at the centre of the outbreak.
Dr Snow removed the handle of the pump and as a result the local people had to get their water from somewhere else. The number of people developing cholera suddenly dropped. It was the water in that well which had been polluted with sewage!
Today cholera is very rare in this country. However, in the developing world there are often serious outbreaks of diseases caused by drinking dirty water.
The use of fertilisers and pesticides by farmers and gardeners may also cause the water company problems if they soak into the ground and find their way into groundwater. This underground water is treated to make sure it is completely safe to drink.
Anglian Water has very good water quality. In 2006, 99% of allsamples tested meet quality standards.
How Do We Clean Water?
When water is taken from rivers, lakes or reservoirs, it travels along pipes to the water treatment works. It is treated to:
The type of treatment depends on the quality of the ‘raw’ water. In the Anglian Water region 50% of supplies are groundwater and very good quality. They only need simple treatment and disinfecting with chlorine to make the water safe to drink.
Water taken from rivers and reservoirs needs more treatment. This involves a number of different processes.
How do we treat the poo?
Anglian Water treats the wastewater and sewage from over 5 million customers a day. The sewage treatment works are connected by over 32,000 km of pipe work.
Up to the 20th Century, human sewage could be put straight on the fields and gardens. It was called ‘night soil’ and in some places, the night soil man was employed to collect it and deal with it. This was still an improvement from Elizabethan times when the contents of pots were just thrown out of the window onto the street!
Now the contents of our toilets and other waste from our homes, schools, farms and factories are sent to the wastewater treatment works where a lot of work is done to do to clean it up!.
First the sewage goes through screens. This gets rid of large items like wood, paper, cloth or plastic.
The sewage goes into settling tanks and most of the solids sink to the bottom. Chemicals are added to speed this up. The water is taken from the top leaving sludge.
How is this water cleaned further?
This water is still dirty and needs further treatment before it can be returned to rivers. A rotating arm sprays the dirty water over a bed of special stones and other materials. There are millions of tiny living things living on these stones and their favourite foods is found in the dirty water! They remove what we are trying to get rid of, leaving the water much cleaner and ready to be returned to the river – all for free!
How is the sludge dealt with?
Bacteria can be added to the tanks in the same way you would add worms to a compost heap. They get to work on the sludge and begin to break it down.
In the past all the sludge would have been dumped at sea, but now this is illegal. The sludge can be dried to produce bio solids. Over half is put on agricultural land.
©2006 Anglian Water Services Ltd