The Treatment Process: Wasterwater

Treatment Plants
   The City of Toronto has four wastewater treatment facilities, Ashbridges Bay, Highland Creek, Humber, and North Toronto Wastewater Treatment Plant. All of these plants deposit the cleaned wastewater back into Lake Ontario once the water meets or exceeds both provincial and federal standards (‘Wastewater’, n.d)

Treatment Process
  The water is first sent through a bar screen to remove the large debris, as it enters the ‘grit tank’ from the screen the water is slowed down to allow heavy materials to settle; both these materials are sent to landfills ('Where Does The Water From Your Toilet Go?', n.d).



   During primary treatment the water is left in another settling tank for several hours to allow s olid particals to settle. The secondary treatment involves aerating the water to allow microorganisms to grow and eat the small bits of organic matter that remain, once the mixture of solids and microorganisms settles to the bottom the solids are collected and excess material is sent back to an aeration tank to treat more water ('Where Does The Water From Your Toilet Go?', n.d).

    In the final step of treatment, chlorine is added to kill pathogens and harmful bacteria from the water before it is finally released back into Lake Ontario (‘Where Does The Water from Your Toilet Go?’, n.d)