Supply

Water supply

“When the well is dry, we know the worth of water.” Benjamin Franklin (1706-1790)

 

Water from a tap – supplied by a pipe. Credit: Alex Anlicker

 The basics of water supply

Most of the water on our planet is in the oceans or locked in the ice caps and it is the small amount of water falling as rain on the continents that sustains all life on Earth.  This means that water supply systems have to get most of their water from groundwater (aquifers) and surface water (lakes and rivers).  Water may also be stored in surface reservoirs formed where a dam has been constructed to hold back water, for example by building a dam wall across a river valley.  Fresh water is used mainly for agriculture, industry and household consumption. Drinking water is essential to life, but we need a safe and clean water supply (water that is not polluted with faecal matter).  This means that before it is piped into our homes water has to be treated by purification and disinfection processes.  Once water is used, wastewater is usually discharged in a sewer system, but before it can be released into a river, lake or the sea this wastewater has to be treated in a sewage treatment plant or wastewater treatment plant.  This treatment removes contaminants and ensures the recovered water is safe to release to the environment. The following website gives is a useful, interactive educational resource The World of Water.  This resource takes you through the water cycle and shows the steps taken to ensure the water we drink is clean and safe and the water used is returned back to the environment safely: http://www.unitedutilities.com/all-about-water.aspx

Find your supplier

By clicking on the map shown on the following website you can find the details of your local water and wastewater suppliers: http://www.water.org.uk/consumers/find-your-supplier

Reservoirs and dams

 

Ladybower reservoir, Derbyshire Credit: Rob Bendall Ladybower supplies clean water to the cities of Derby and Leicester in England.

 

Llyn Brenig, Denbighshire, Wales Credit: Dot Potter Llyn Brenig manages the flow in the River Dee and protects the water supply for  North West England and north-east Wales.   A list of the dams and reservoirs in the United Kingdom is available at: https://en.wikipedia.org/wiki/List_of_dams_and_reservoirs_in_United_Kingdom The following website gives an introduction to dams and some of the issues associated with them.  It includes information about different types of dams, how dams are used, dam building methods and how people and the environment are affected by dams. http://britishdams.org/about_dams/default.htm

How do water treatment plants work?

Surface water and ground water supplies are treated to make the water potable (safe to drink) and palatable (agreeable to taste).  Various processes may be used in water treatment plants.  Examples of the processes used are: • screening (to remove larger particles e.g. leaves); • settling (to remove sand and larger silt particles); • filtration (to remove smaller silt and clay particles); • disinfection (to remove disease-causing microorganisms); • lime softening (to precipitate calcium and magnesium ions); • stabilization (to prevent corrosion and scale formation); • activated carbon adsorption (to remove chemicals that may affect the taste or smell of the water); • fluoridation (to increase the concentration of fluoride in the water to reduce tooth decay). The following website gives further details of how water treatment plants work: http://www.freedrinkingwater.com/water_quality/quality1/1-how-do-water-treatment-plants- work.htm A booklet that gives information and explains how the quality of your water can be affected in and around your home and the practical steps that you can take to stop this happening is at: http://www.unitedutilities.com/documents/caringforwater_in_your_home.pdf

Wastewater treatment plants

 

Overview of the wastewater treatment  plant of Antwerpen-Zuid, Antwerp (Belgium). Credit: Annabel There are various stages of treatment in wastewater treatment plants. The first stage is primary treatment where the sewage is held so heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface.  Settled and floating materials are removed and remaining liquid then goes to the  secondary treatment stage when dissolved and suspended biological materials are removed by micro-organisms. These micro-organisms may have to be removed from the treated water before it is discharged or undergoes tertiary treatment.

 

Simplified process flow diagram for a typical large-scale treatment plant Credit: Leonard G. This YouTube clip explains how we all make sewage and the sewage treatment process: https://www.youtube.com/watch?v=8isr9nSDCK4

How much water do you use?

The average person in the UK uses 150 litres of water every day.  This includes water used for drinking, cooking, cleaning, washing, flushing toilets, washing cars or watering the garden.  It does not include the water used in production processes (e.g. to produce a burger requires 2400litres of water)

How much water do you waste?

Water is a precious resource and demand for water has increased over recent years.  This increased demand is partly a result of population growth, but it is also linked to improvements in living standards.  It is important that we all begin to avoid wasting water. About a third of our water usage is accounted for by waste.  For example, leaving the water tap running while you are cleaning your teeth can waste 5 litres of water per minute.  A dripping tap can waste although new dual flush toilets use only 2.6 and 4 litres per flush, old toilets can use up to 14 litres per flush. Anglian Water has produced a fact file about using water at home: https://www.anglianwater.co.uk/_assets/media/Fact_File_5_-_Using_water_at_home.pdf

How can we save water?

The level of increase of use of water is not sustainable, and we all need to avoid wasting water. About one third of our water usage is accounted for by waste. 30% of the water we use every day goes down the toilet. Examples of ways of saving water in the home are: • taking short showers instead of deep baths; • not leaving the tap running when cleaning teeth; • washing dishes in a bowl of water, rather than washing dishes under a running tap; • only filling a kettle with the amount of water you need to make a hot drink; • cleaning and peeling vegetables in a bowl of water rather than under a running tap. South Staffs Water has produced a booklet about water use in the home.  The booklet also lists ways in which you can save water: http://www.south-staffs-water.co.uk/publications/your_home/WaterUseHome.pdf The Water Story, produced by South West Water, is a resource for primary schools.  It consists of two online, presentations with accompanying teachers’ notes and worksheets for Key Stages 1 and 2.  Click below to download the teachers’ notes and worksheets: http://www.sww.ebcnet.co.uk/teacherscentre.html

Created by ESTA members: Tracy Atkinson, John Reynolds, Stewart

Taylor, Geoff Selby-Sly, Maggie Williams, Peter Williams

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