using resources

• finite resources are natural resources that are being used up faster than the rate at which they can be produced
• renewable resources are natural resources that are being used up at the same rate as they are being produced, and can be replaced
• potable water has been treated and is safe to drink, it may however have many substances dissolved in it
• fresh water is collected in rivers, lakes or in the ground, but may contain pathogens
• potable water must

  • not contain too much dissolved salt (ions)
  • pH between 6.5 and 8.5
  • not contain dangerous bacteria or microbes
• fresh water

  • fresh water is pumped from a resevoir, removes large objects like twigs
  • filtere through sand and grit to remove small solid dirt
  • bubble Chlorine to sterilise water and kill pathogens (could also use Ozone and UV)
  • check pH, and water stored
• desalination is the process of removing salt