waste water treatment

    Cards (21)

    • What are the two main purposes of treating wastewater?
      To reuse it or safely return it to natural water sources
    • What are the three main sources of wastewater?
      • Domestic
      • Agricultural
      • Industrial
    • What does domestic waste refer to?
      Household waste like water from showers, sinks, and toilets
    • Where does domestic wastewater go after being flushed?
      It goes into the sewers and heads for sewage treatment plants
    • What type of wastewater is produced by agriculture?
      Nutrient runoff from fields and animal waste from farms
    • What do industrial sources of wastewater typically involve?
      Factories that make and use chemicals
    • Why must all wastewater be treated before disposal?
      To make it safe and prevent pollution and health risks
    • What is generally required for treating domestic and agricultural sewage?
      Removing organic matter and harmful microbes
    • What additional steps are needed for treating industrial wastewater?
      Extra steps to remove harmful chemicals
    • What are the three main steps in sewage treatment?
      1. Screening to remove large objects
      2. Sedimentation to separate sludge and effluent
      3. Biological breakdown of organic matter
    • What happens during the screening step of sewage treatment?
      Large objects like twigs and plastic bottles are removed
    • What occurs during sedimentation in sewage treatment?
      Heavier solid bits sink to the bottom to form sludge
    • What is the difference between effluent and sludge?
      Effluent is the lighter part on top, while sludge is the heavier solid at the bottom
    • What conditions are maintained in the effluent tank during biological breakdown?
      Aerobic conditions with oxygen supplied
    • What conditions are maintained in the sludge tank during biological breakdown?
      Anaerobic conditions with little or no oxygen
    • What is produced during anaerobic digestion of sludge?
      Methane, which can be captured and burned for energy
    • What can the remaining digested waste from sludge be used for?
      As fertilizer, as it is rich in nutrients
    • What additional stages may be required for wastewater containing toxic substances?
      Adding chemicals to precipitate metals or using ultraviolet radiation
    • Why is treating wastewater considered easier than desalinating salt water?

      It requires less effort and resources
    • Why do some countries rely on treating wastewater for drinking supplies?
      Because they have a limited water supply
    • What is the example of a country that relies on treating wastewater for drinking supplies?

      Singapore