waste water treatment

Question 1

What are the 3 sources of waste water

Answer 1

domestic (houses)
agricultural
industrial

Question 2

Explain the process of how waste water is treated (to remove harmful chemicals) before returning to the environment

Answer 2

• first the water is screened to remove large waste
• then in the sedimentation tank the organic waste sinks to the bottom to form sludge
• then air is passed through the effluent (liquid waste)
  as the air provides oxygen for aerobic treatment to kill harmful microbes
• then this is sent to the final setting tank the clean water is returned to the environment
• the sludge from this tank and the sedimentation tank is treated anaerobically and which releases methane which can be used for heat and electricity