Solid and Liquid Waste Management Environmental Science 20

Sources of Solid Waste What is Solid Waste? Solid Waste is any solid or semi-solid material that has been discarded Each year, Canadians generate 30 million tonnes of. This is equivalent to the mass of 250 CN Towers Waste Stream is the movement of waste from its source to its final destination. Solid waste enters the waste stream from 3 major sources: Agriculture Industry Municipalities

Agricultural Solid Waste Farms, Ranches, Feedlots, and many Slaughterhouses are the sources of agricultural wastes. Sources of Agricultural Waste: Animal waste (Manure) Organic Matter leftover after harvest Fertilizer waste is often burned (air pollution) Rainwater and irrigation run off Livestock water may also carry microorganisms such as E. coli, that can harm human health

Industrial Solid Waste Industrial solid waste may come from manufacturing, construction, mining, and other industries. These wastes range from chemicals used in manufacturing to wastes produced during construction or demolition. Mines produce mine tailings – particles left over after ores have been processed. Some mines, such as Uranium mines produce hazardous waste which is difficult to dispose of safely.

Municipal Solid Waste Municipal Solid Waste (MSW) includes al garbage – including things that can be recycled and composted – from homes, businesses and schools. Canada is among the world leaders in the yearly production of MSW. Each Canadian produces an average of 1030kg of waste per year.

Where does it go? Landfills Landfills are disposal sites for solid waste where the waste is buried between layers of soil, filling in low lying ground. Landfill provide some benefits to the environment: Solution for solid waste management Some landfill produce gases that can be used for electricity Compactors are used to reduce the volume and of waste and therefore the size of the landfill. This also reduces the smell helping to limit insects and rodents.

How a Modern Landfill Works

Leachate and Landfill Gas As water seeps down into the landfill, chemicals from garbage dissolve in it. The liquid that results is called leachate. Leachate can pollute nearby soil and waterways if it leaves the landfill. Modern landfills have rubber or clay liners to contain the leachate and prevent it from entering the surrounding ecosystem and drainage systems are installed to collect it. Modern landfills are also built far from waterways to further minimize polluting of the ground water. Landfill gas is created by bacteria as they break down the organic materials in the garbage. The gas is a mixture of methane and carbon dioxide (both greenhouse gases). Landfill gas is also flammable and explosive. Technology can help manage landfill gas. Gas capture and combustion can be used to generate electricity to power homes and businesses.

City of Saskatoon Landfill Saskatoon Light and Power – Green Power Initiatives https://www.saskatoon.c a/services- residents/power- water/saskatoon-light- power/clean-power- generation-initiatives City of Saskatoon https://www.saskatoon.c a/services- residents/waste- recycling/landfill Contaminated Groundwater Article: http://www.cbc.ca/news /canada/saskatoon/cont aminated-groundwater- likely-leaking-from- saskatoon-landfill-into- river-opposition-1.2596527

Available Space About 80% of Canadian waste goes into landfills. Public resistance comes from concern over water contamination, disease-carrying organisms, odors and truck traffic. The acronym NIMBY (not in my backyard) summarizes the public opinion. The number of landfills has been declining: Some do not meet regulations Others have reached their capacities Area with high population densities are challenged to find sites that are geologically suitable and there is opposition from people in the area

Where does it go? Thermal Treatment Thermal Treatment is the processing of solid waste at high temperatures. Reduces the volume of waste in landfills by 10-20%. There are several types of Thermal Treatment: Type Process End Products Incineration Complete combustion at temperatures over 850°C CO2, H2O, ash, and other air pollutants Pyrolysis Thermally processed in oxygen at lower temperatures Synthetic gas called syngas (mixture of gases which are pollutants) Gasification Thermally processed with limited oxygen, but enough for total combustion Syngas and solid residue

Where does it go? Exportation Densely populated areas may look to export their waste to other places. Transporting solid waste to another region is expensive and many people believe that shipping wastes to distant places is unacceptable.

Liquid Waste Management Wastewater is any waste that occurs in or can be changed to liquid form Wastewater can come from many places: Agricultural – wastewater from farms and feedlots can contaminate surface and ground water with run off from fertilizers and pesticides Industrial – Sources include: petroleum products, metals, nutrients and sediments Municipal – May come from homes, businesses, schools and urban surfaces. Waste water from these sources is often grouped under two headings: Storm water Sewage

Wastewater from Municipal Sources Storm water includes rain and melting snow that drains from driveways, roofs, roads and other urban surfaces. Sewage includes any materials that are rinsed down a drain or flushed down a toilet. Sewage may also contain: Plasticizers Medicines Pesticides Flame retardants

Treating Sewage – Septic Systems Where land is available and populations are low, septic systems are an effective way to treat sewage.

Treating Sewage – Municipal Sewage Cities and towns are linked to sanitary sewers. Sewage treatment follows 3 main steps: Primary Treatment – physically separates large solids from sewage Secondary Treatment – involves the biological breakdown of dissolved organic compounds Tertiary Treatment – inorganic substances are removed (nitrates and phosphates)

Treating Storm Water Sanitary sewers are often connected to storm sewers These sewers are routed to treatment facilities rather than discharged into waterways This plan works well in dry weather, but can get over loaded during storms. This can cause sewage backup Potential problems: Erodes stream banks Increase sediment can harm aquatic life Temperature changes in the water reduces dissolved oxygen

Questions Read sections 7.1-7.2 and answer the questions.