thermal pollution

• causes of thermal pollution?

  main source of hot water is steam turbine power stations that use cold water from nearby bodies of water to condense steam

  the coolant water is returned to river or lake at a higher temp
• effects of thermal pollution

  -effects dissolved oxygen concentrations, higher temps created deoxygenated water

  (1 litre of water at 20degrees can hold up to 6cm3 of dissolved oxygen)

  -enzymes and proteins, very high temperatures can cause denaturation

  -decreased growth rate, exotherms (higher metabolic rate) means less energy for growth, eggs hatch earlier (underdeveloped), introduced species can survive better in warmer conditions out competing native species, toxic pollutants can spread easier in warmer conditions
• how can thermal pollution be controlled?

  temperature reduction using cooling towers

  cooling towers allow water to become cool before being returned to rivers and lakes
• how to cooling towers work?

  hot water is sprayed into the towers

  air in the towers absorbs the heat from the water, which rises and escapes

  causes cooler air to be drawn to the bottom of the tower, cooling water

  the tower mixes water and air, allowing oxygen to dissolve