Solid Waste Management

What is solid waste? Solid waste is any material, non-hazardous or hazardous, that is discarded.

The Waste Stream Think of a stream of water, which gathers water from many sources until it reaches its final destination in a lake or ocean. The waste stream is the movement of waste from its many sources to its final destination – usually a landfill or an incinerator The three main sources that feed the waste stream are: Agriculture Industry Municipalities

Agricultural Solid Waste Comes from farms, ranches, feedlots, and slaughterhouses Made up of: Animal waste (manure) Plant debris left over after harvesting Animal tissue left over after slaughtering and processing

Industrial Solid Waste Comes from manufacturing, construction, mining and other industries Includes chemicals used during processing, mine tailings, and waste produced during construction and demolition

Municipal Solid Waste Includes all waste from homes, businesses, and institutions (schools, hospitals, etc.) Canada leads the world in per capita production of solid waste…. Sad news. 80% of this solid waste ends up in landfills

In Canada, who is responsible for managing waste? Municipal governments -- collecting and managing waste from homes for recycling, composting, and disposal Provincial and territorial governments -- approval, licensing and monitoring of waste management operations. Federal government -- international and interprovincial movements of hazardous waste, releases of toxic substances to the air, land, and water, and activities on federal lands.

Solid Waste Disposal Methods 1) Landfill 2) Incineration (burning) 3) Composting (of organic wastes) 4) Dumping at sea

1) Landfill A landfill site is an area of land where solid waste is disposed of by burial Many landfill sites are publicly owned and run, but some are private businesses Collection and transportation typically account for 75% of the total cost of landfilling

Modern Landfill Methods In a modern landfill, solid waste is spread in layers about 3 metres deep and then compacted by bulldozer and covered with a thin layer of soil, which is also compacted. Contamination of surface and groundwater is minimized by lining and contouring the fill, compacting and planting the cover, selecting proper soil, diverting upland drainage, and placing wastes in sites not subject to flooding or high groundwater levels. Gases are generated in landfills through anaerobic decomposition of organic solid waste. Gas can be collected and used to generate electricity or provide heating fuel. http://science.howstuffworks.com/environmental/green-science/landfill.htm

Benefits of Landfill Landfill is the cheapest method of solid waste disposal if suitable land is available close to the source of waste

Negative Impact of Landfills Pollution of the local environment – groundwater contamination and soil contamination by leakage from the dump Off-gassing of methane, a powerful greenhouse gas, from the decomposition of organic matter Presence of disease vectors, such as rats and flies Nuisance factors – dust, odour, vermin, noise from machinery Damage to roads by heavy garbage trucks Injuries to wildlife Difficulty in locating new sites

2) Incineration Organic materials in solid waste are burned Also called “thermal treatment” Burning converts the waste into ash, flue gas, and heat Ash is mostly formed from the inorganic (noncombustible) part of the waste. It can be solid lumps or particulates carried by the flue gas Flue gases must be cleaned of gaseous and particulate pollutants before they are released into the atmosphere The heat produced is sometimes used to generate electrical power

Incineration Technology The typical incineration plant for municipal solid waste is a moving grate incinerator. A single moving grate boiler can handle up to 35 metric tons of waste per hour, and can operate 8,000 hours per year with only one scheduled stop for inspection and maintenance of about one month's duration A crane dumps waste into one end of the grate, which moves it into the combustion chamber and then to an ash pit Air is needed for combustion. Holes in the grate supply air from below, and secondary air is also blown by nozzles over the grate. The air helps cool the grate and mix the flue gases, ensuring better combustion Flue gases must reach a temperature of 850 °C for 2 seconds in order to break down toxic organic substances. Auxiliary burners are available as a back-up in case the waste materials don’t burn hot enough. Flue gases are then cooled by transferring the heat to steam, which can be used to generate electricity. http://www.youtube.com/watch?v=lmtOuAed5nM

Benefits of Incineration Incinerators reduce the amount of waste going to landfills by about 90%, which extends the life of landfills Useful in countries, like Japan and Denmark, where there is little land available for landfills Incineration of medical wastes and sewage sludge can break down pathogens and organic toxins. Resulting ash is sterile and safe to landfill Heat produced can be used to generate electricity New incinerator technologies remove most of the pollutants from flue gases

Negative Impact of Incineration Flue gases may contain significant amounts of particulate matter, heavy metals, dioxins, furans, sulfur dioxide and hydrochloric acid. If the plant isn’t required by law to clean the flue gases, these pollutants will be released into the atmosphere. Fine fly ash can escape the cleaning process, adding particulate pollution to the atmosphere Incineration produces carbon dioxide, contributing to global warming Incinerators can devalue surrounding properties because they are unsightly and waste deliveries can smell bad. People living near an incinerator often complain of respiratory problems http://www.youtube.com/watch?v=g8ycXLvOuBM

3) Composting Composting is the process of breaking down organic materials like kitchen waste and yard waste into a nutrient-rich material called compost, or humus Compost can be used in gardens, landscaping, horticulture, and agriculture, and environmental restoration

Large-Scale Composting Technology Modern, large-scale composting is a multi-step, closely monitored process with measured inputs of water, air and carbon- and nitrogen-rich materials. Decomposition is aided by shredding the plant matter, adding water and ensuring proper aeration by regularly turning the mixture. Worms and fungi further break up the material. Aerobic bacteria carry out the chemical process of decomposition, converting the inputs into heat, carbon dioxide and ammonium. The ammonium is further converted by bacteria into plant-nourishing nitrites and nitrates through the process of nitrification.

Composting at Home Simple composting is a natural process that can be done at home. You collect organic waste in a pile or container outdoors and let nature do its work. Layer different organic materials (kitchen scraps, grass clippings, leaves, ashes from the fireplace, shredded paper, garden soil), mix the pile occasionally to aerate it, and water it once in a while. It takes a couple of months for this material to break down and form humus

Ottawa’s Green Bin Program Organics recycling is an important part of Ottawa’s long term Waste Strategy. Diverting residential organic waste away from landfill saves the City millions of dollars and reduces the need for more landfill sites. Waste in green bins is collected every week.

What you can put in your green bin Other things: Animal bedding, ashes, dryer lint, cotton balls, floor sweepings, vacuum bags, food-soiled paper towels, napkins, tissues, food-soiled pizza boxes, kitty litter, microwave popcorn bags, paper coffee cups, plates and muffin wrappers, pet fur, hair and feathers, soiled paper, boxboard and cardboard, sugar, flour and potato paper bags, waxed paper, cardboard and cold drink cups, wooden popsicle sticks, toothpicks, sawdust, wood chips, small untreated wood scraps Never: pet poop, disposable diapers, toxic waste, plastic Food waste and scraps: Peelings, pits, seeds, nuts & shells, meat, bones, sauces, pet food, coffee grounds & filters, tea bags, breads, cakes, pasta, all food leftovers! Yard waste: Branches, twigs and hedge trimmings, leaves, plants, weeds, grass clippings

Grinding Wood for Mulch Wood and bark scraps can be ground and used as mulch for landscaping and gardens

Benefits of Composting Easy to do and free when you do it at home Produces compost, which can be used by gardeners, landscapers and farmers to improve soil and help plants grow better Compost helps soil by improving its fertility, texture, and ability to hold water. Microscopic organisms in compost help aerate the soil, break down organic material for plant use, and ward off plant disease. Composting reduces the amount of organic waste going to landfills by as much as 30%

4) Ocean Dumping Marine debris, also known as marine litter, is human-created waste that has deliberately or accidentally been released into an ocean Floating oceanic debris tends to accumulate at the centre of gyres and on coastlines, frequently washing up onto beaches Deliberate disposal of wastes at sea is called ocean dumping. As humans have increased their use of plastic, many types of plastic items end up in the ocean, where they pose a serious threat to fish, seabirds, marine reptiles, and marine mammals, as well as to boats and coasts.

Great Pacific Garbage Patch The world’s largest garbage dump is located thousands of miles from land. Also known as The Great Pacific Garbage Patch, the Pacific Trash Vortex is an area of marine debris floating in the Pacific Ocean. This collection of trash is characterized as a plastic-soup due the high concentrations of suspended disposable plastics that have been trapped by the spiraling currents of the North Pacific Gyre.

http://www.youtube.com/watch?v=XxNqzAHGXvs What’s an Ocean Garbage Patch? http://www.youtube.com/watch?v=J-gqJAsXiKQ http://planetgreen.discovery.com/videos/focus-earth-2-pacific-plastic-the-garbage-patch.html