Sustainability - Water

water that has been used in the home, in a business, or as part of an industrial process

social: - competition for clean water in ELDCs results in conflict - struggle to access water supplies in ELDCs leads to increases in disease - greater demand for domestic water use (shower, dishwasher) in EMDCs may lead to water shortages economic: - ELDCs find it expensive to upgrade sewers - more money needed from GOV and NGOs to manage water extraction and conservation environmental: - over extraction of water can damage ecosystems and destroy habitats - increased water pollution from industrial processes

• screening - leaves, twigs and eny large debris are removed by screens • clarification- mud and silt are removed. Alum (aluminium sulphate) and lime (calcium hydroxide) are added to make it group together as sludge. This is taken away to a landfill site where it turns back into mud. • filtration - most treatment works have to filter their water. A special sand filter removes the last tiny bits of grit and any remaining colour. • disinfection - the water now looks clean but may still contain bacteria. A small amount of chlorine is added to kill the bacteria. • pH correction - the water is still too acidic to drink, so more lime is added to make the water less acidic and less corrosive to metal pipes. The water is now ready to drink.

sewage is taken to an aerobic digestion tank where bacteria and other microorganisms break down the waste until it is safe to be released into the environment

• wells can be dug but the water is often contaminated • gravity-fed shemes are used for streams on hillsides • boreholes require more equipment to dig but can provide water by using a hand/diesel pump

• industrial - used as coolent, solvent, steam for power generation • agricultural - irrigation, hydrating livestock • domestic - washing, cooking, cleaning

• contaminated water has massive risks for wildlife and humans and increases the risk of many diseases • oil spills are poisonous to fish, mammals, and birds when ingested. • thermal pollution can cause non-native organisms and micro-organisms to move into new ecosystems which can have negative affects on fragile ecosystems.

• SEPA monitor and regulate scotlands water • they have a flood warning system • they monitor the quality of the water • they regulate water activities - discharges to groundwater and surface-water, removal of sediments, replacement of weirs