Clean Water Professor Stuart Moy School of Civil Engineering and the Environment
Contents 1. Introduction 2. A global view 3. An historical perspective 4. Bilharzia and other diseases 5. Separation of human waste from water, the need for sanitation. 6. The future 7. Summary
Introduction • Water is essential for life. • People die after three days without water • But people also die if they drink the wrong type of water
Why clean water? Impurities in water will cause disease or will be poisonous Unclean water has a profound effect on life expectancy
A global view of clean water • In developed countries people expect water to be clean and drinkable. • In the UK we turn on the tap and water flows. • In Greece when you order a coffee you will automatically be given a glass of water. • But this is not the case in developing countries. • In many areas there is insufficient water and there is no guarantee that it will be clean.
A global view of clean water
A global view of sanitation
A global view of clean water • Why link water supply and sanitation? • Because water supply and sanitation go hand in hand to produce clean water.
An historical illustration – London 1800’s What was the problem? Go to an old graveyard and read the inscriptions. Death in childhood was massive. For those that reached adulthood life expectancy was less than 40 years. Disease was everywhere. Cholera was one of the worst killers. London :1848-49 14137 deaths 1853 10738 deaths Cholera is a water borne disease
What caused the problem? EXCREMENT
• Everyone needs to ‘go’ about once a day. • In the early 1800’s the excrement was dumped directly into the River Thames. • The river was an open sewer carrying disease and smelling terrible.
The river was at the same time the source of people’s drinking water.
What was done about it? Not much, until 1858. 1858 was the year of the ‘Great Stink’. The smell from the river was so appalling that parliament thought of moving outside London. Parliament finally acted. The Metropolitan Board of Works was set up to deal with the problems. Its’ Chief Engineer was Joseph Bazalgette. Those of you who know London might like to know that the Board of Works became London County Council and then Greater London Council. The GLC was abolished by Margaret Thatcher in 1986. The offices were in County Hall by the London Eye.
Sir Joseph Bazalgette Born: Enfield, London, 1819 Died: Wimbledon, 1891 President of the Institution of Civil Engineers, 1883 One of his referees was Isambard Kingdom Brunel!
The genius of Bazalgette 1858 – 1875 Installed 1800km of street sewers Installed 133km of interceptor sewers The interceptors carried the raw sewage to two giant sewage works, Crossness (Beckton), north of the river and Plumstead, south of the river. All still in use. Sewers were brick lined using very high quality materials. It is possible to go down into the interceptors!!
Sectional view of tunnels, Wick Lane, showing construction techniques Crossness works at Beckton Both prints from London under London, Trench and Hillman authors
We don’t build like this anymore! Abbey Mills Pumping Station Interior of Crossness Pumping Photo by Gordon Joly Station
Water supply Monopolised by private companies, eight dominated in London Originally they competed against each other but they set up a cartel in 1811. No competition = no improvement Water still taken from Thames 1852 Metropolis Water Act. All reservoirs covered, water filtered through sand. Intakes moved to non-tidal section above Teddington. 1902 Supply in Public Ownership – Metropolitan Water Board. 1973 became Thames Water. Privatised in 1989.
Result End to cholera and other epidemics. Quality of life and life expectancy greatly increased. Thames is now a clean river. Fish have returned to what were the most polluted stretches. Bazalgette’s legacy Embankments –attractive part of central London. Several bridges across the Thames Woolwich Ferry
Where are we now? • In many ways Bazalgette was too good. • Under investment in maintenance and no allowance for extra capacity has put the system under stress. • Almost daily raw sewage is released into the Thames. • There are huge fat deposits (fatbergs) blocking the sewers.
About 39 million tonnes of raw sewage are released into the Thames each year Picture taken on July 4, 2013 and released by waste management firm CountyClean Environmental Services shows a congealed ball of fat and waste in an underground sewer in Kingston, southwest London. The 15-tonne ball -- dubbed Britain's biggest ever 'fatberg' -- was removed from a London sewer after a 10-day operation following complaints from local residents that they couldn't flush their toilets. (CountyClean Environmental Services/AFP)
Thames Tideway A 25km long, 7.2m diameter tunnel to cater for the excess sewage and rainwater runoff. Cost £4.2 billion!
• Similar measures were taken in other parts of the UK. • What about the rest of the world? • Developed countries went the same way as the UK. • My guess is that the British Empire helped in some areas, for example, Canada, Australia. • But in many places medical knowledge wasn’t up to the task and in some areas it still isn’t. • Politics and national interest are also problems. • Most things ought to be possible with sufficient money
Some water borne diseases Disease Microbial Agent Source of agent in drinking water Amoebic dysentry protozoan sewage, non-treated water Cyclosporiasis protozoan parasite sewage, non-treated water Camphylobacteriosis Camphylobacter jejuni water contaminated with faeces E coli infection Escherichia coli contaminated water Leptospirosis Leptospira water contaminated with animal urine Typhoid fever Salmonella typhi water contaminated with faeces Poliomyoletis Polio virus water contaminated with faeces Schistosomiasis parasitic flatworms from contaminated fresh water (Bilharzia) contaminated snails Malaria protozoan parasite mosquito carrier lives in stagnant water
Bilharzia and other diseases • When Europeans first colonised parts of Africa they formed an impression that the indigenous population was lazy. • In fact this lethargy was due partly to a variety of water borne illnesses – for example malaria and bilharzia. • Another factor was ‘sleeping sickness’ resulting from the bite of the tsetse fly.
Bilharzia and malaria are still major problems
Bilharzia is a global problem
The bilharzia (schistosomiasis) cycle
An adult worm Source - Wikipedia
Did you notice the causes of the cycle? Faeces and urine in the water i.e UNCLEAN WATER Bilharzia will only be eradicated by a two pronged approach. 1. Sanitation – separate human waste from the water. 2. Interfere with the bilharzia cycle.
Malaria – global distribution
• Note that malaria is prevalent in many bilharzia areas. • Malaria is not so much a problem of unclean water. It is spread by the female anopheles mosquito which thrives in stagnant water. • Between them the two are devastating – causing poverty as much as being caused by poverty. • Combined with HIV the problem is even worse. HIV reduces people’s resistance to malaria.
• Malaria kills 1.5 million to 3 million people each year, mainly in sub-Saharan Africa and mainly children under 5. • There is as yet, no fully effective vaccine (although we are close). • Prophylactic drugs are readily available but too expensive for indigenous people. There is some evidence that mosquitoes are becoming resistant. • Insecticides such as DDT are effective. • It could be controlled or even eliminated but is anyone willing to pay? • The WHO Global Malaria Programme aims to eradicate malaria by 2030
Separation of human waste from water Provision of clean water – a waterwell. Low cost to install and run but must be kept clean
Better still Water treatment works – but expensive to build and run
But still need sanitation Clean water isn’t enough
Where are we now?
Some typical statistics Percentage of population with access to safe drinking water Country % Country % Country % Country % Albania 97 Algeria 89 Azerbaijan 78 Brazil 87 Chile 93 Cuba 91 Egypt 97 Iraq 85 Iran 92 Mexico 88 Morocco 80 Peru 80 Syria 80 Sudan 67 South Africa 86 Turkey 82 Tunisia 80 Venezuela 83 Zimbabwe 83 Source - Wikipedia
What of the future? The world's supply of fresh water is running out. Already one person in five has no access to safe drinking water. Will we see wars being fought over water?
Fresh water flashpoints Water trouble spots, source BBC News webpage, World Water Crisis
Recommend
More recommend
