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Flush It and Forget It: Human Waste all metabolic processes produce waste digestive waste is egested (feces)and metabolic waste is excreted (sweat and.

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Presentation on theme: "Flush It and Forget It: Human Waste all metabolic processes produce waste digestive waste is egested (feces)and metabolic waste is excreted (sweat and."— Presentation transcript:

1 Flush It and Forget It: Human Waste all metabolic processes produce waste digestive waste is egested (feces)and metabolic waste is excreted (sweat and urine) the management of waste became more complex as humans formed permanent settlements Romans developed aqueducts to bring water into settlements for drinking and flushing waste water

2 the outhouse was adequate for rural areas as long as it was isolated from the water supply large urban centres require kilometres of underground pipes with flush toilets attached using miilions of litres of water to move waste to a sewage treatment plant, out of sight and mind for the average citizen Where is Collingwoods STP? Who operates it?

3 while modern sanitation facilities have virtually eliminated typhoid and cholera from the developed world, in some ways the flush toilet has been an environmental disaster, overusing and polluting our water supplies and breaking the nutrient cycle moving waste in a stream of clean, potable water and then cleaning the water again is a complex and expensive process of questionable effectiveness

4 What needs to be removed during treatment? How clean is the water after treatment? What happens to the solid waste that is removed from the water? What happens to the water after it is cleaned? Activity: Water Use in the Home

5 Wastewater Treatment Private Systems rural dwellings have a septic system which consists of a septic tank and a drainage field a septic tank can be made of steel, concrete, plastic, or polyethylene wastewater entering the tank (influent) separates into scum and grease at the surface and solid sludge which settles to the bottom, with relatively clear and watery effluent between effluent drains out of the tank through a distribution box into two or more perforated pipes laid in gravel-filled trenches bacteria begin decomposition of organic material in the septic tank but the bulk of the breakdown occurs in the drainage field where most toxic materials get absorbed or transformed

6 provincial regulations specify the size of the septic tank, the location, the slope of the grade, and characteristics of the drainage field Health And Environmental Concerns Associated With Septic Systems: clogged pipes can result in sewage backup sludge needs to be pumped and then incinerated or sent to a landfill the drainage field requires sufficient land area soil must be permeable for proper drainage commercial additives may be required to supplement the natural microbes

7 Public or Municipal Systems 75% of Canadians are served by municipal sewer systems sewage flows through a service line and sewer main by gravity until it reaches 8-10 m, where a lift station raises it to flow by gravity to a central station municipal wastewater is composed of sanitary sewage and stormwater, often carried in separate systems (the overflow of sewage into the stormwater system is the main reason for closing beaches along the Lake Ontario shore after heavy rains) stormwater is usually discharged untreated directly into the environment

8 pretreatment involves screening out large debris (i.e. sticks, plastic, rags, tampons, condoms, etc.) primary treatment involves the settling of organic and inorganic solids (sludge) and flotation of scum and grease at the surface of a tank (ala septic tank) after which the effluent may be discharged secondary treatment utilizes activated sludge treatment involving anaerobic bacterial digestion of the sludge and aerobic bacterial digestion of the effluent secondary effluent enters a secondary settling tank after which it is discharged or sent for further treatment

9 tertiary (advanced) treatment involves one or more physical, chemical, or biological processes to remove suspended or dissolved pollutants such as heavy metals, organic chemicals, and nutrients (P, N) tertiary effluent is sent to a landfill, incinerated, composted, or used as fertilizer secondary or tertiary effluent is disinfected of disease-causing organisms by chlorination or ultraviolet radiation

10 New Methods of Sewage Treatment bioremediation involves living organisms such as bacteria, fungi, and plants to degrade hazardous contaminants or transform them into less harmful compounds

11 phytoremediation uses green plants to improve contaminated soil or groundwater by absorbing the contaminants or changing them into non-toxic forms

12 the aquatic plants in wetlands can clean water by destroying fecal organisms, absorbing heavy metals, and breaking down organic compounds (i.e. removing P and N) genetic engineering of plants can give them enhanced abilities to absorb heavy metals Comparison of Contemporary and Ecosystem Based Sewage Treatment

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