Wastewater TreatmentWastewater Treatment

Wastewater TreatmentWastewater Treatment

• Waste water is collected in a sewer system Waste water is collected in a sewer system (a series of underground pipes that carry (a series of underground pipes that carry water to facility)water to facility)

• Blackwater – water containing feces and Blackwater – water containing feces and urineurine

• Greywater – water from bathing, washing Greywater – water from bathing, washing machines and sinksmachines and sinks

• Stormwater runoff – from roads, roofs and Stormwater runoff – from roads, roofs and other areasother areas

Steps of Treatment at the Steps of Treatment at the FacilityFacility

• 1. Preliminary Treatment – water 1. Preliminary Treatment – water passes through a screenpasses through a screen

• 2. Primary Treatment – settling tank – 2. Primary Treatment – settling tank – solids settle to the bottomsolids settle to the bottom

• 3. Secondary Treatment – Biological 3. Secondary Treatment – Biological treatment to remove organic mattertreatment to remove organic matter

• 4. Final Treatment – Chlorine added 4. Final Treatment – Chlorine added and water released into Lake Ontarioand water released into Lake Ontario

Treatment of SolidsTreatment of Solids

• 5. Solids Processing – bulk sent to 5. Solids Processing – bulk sent to the “digester”; micro-organisms use the “digester”; micro-organisms use organic material in the solids as food organic material in the solids as food and convert to methane gasand convert to methane gas

• Gas used for electricity or heating Gas used for electricity or heating the plantthe plant

• After 15 days, solids remaining sent After 15 days, solids remaining sent to landfill or incineratorto landfill or incinerator

Septic Systems (Rural Septic Systems (Rural Areas)Areas)

• Solids trapped in Solids trapped in septic tank where septic tank where bacteria slowly bacteria slowly digest wastesdigest wastes

• Liquid flows to the Liquid flows to the drainage bed and drainage bed and gradually soaks into gradually soaks into groundground

QuestionsQuestions

• Explain in your own words how Explain in your own words how greywater is different from blackwatergreywater is different from blackwater

• List 2 sources of wastewaterList 2 sources of wastewater

• What is the purpose of the primary What is the purpose of the primary stage of sewage treatment?stage of sewage treatment?

• Explain the difference between a Explain the difference between a septic system and a sewage systemseptic system and a sewage system