Hazardous Waste

Carbon Absorption

- Carbon particles bind to hazardous chemicals in waste which can then be removed for disposal, carbon is reused

Disposal

- Hazardous waste landfill incineration - Deep well injection

Disposal of Hazardous Wastes 1. Deep-well injection

- Liquid hazardous waste are injected into wells, stored below surface - maybe geological or man-made - modern wells have a non- porous casing and reinforced with cement

Hazardous Wastes from Municipal Sources

- Many consumer products become hazardous waste when they are discarded. Some examples include batteries, antifreeze, paint, light bulbs and cleaners. Electronic devices are particularly problematic. They are replaced frequently and as costly to fix as to replace. These are often referred to as e-waste.

Treatment

- Neutralization of acids and bases - Filtration and separation - Biodegradation

Hazardous Wastes From Agriculture

- Pesticides are harmful to humans and other organisms. Leftover pesticides, those past due dates, equipment such as spray bottles and residue left in soil can all pose a risk. - Persistent Pesticides do not break down over time but instead remain in the environment for many years. DDT is one such pesticide. It belongs to a class of hazardous organic compounds called chlorinated hydrocarbons.

Recycle

- Recycle solvents for other uses - Exchange waste with other industries - Burn waste as fuel

Reduce and Re-use

- Stop leaks - redesign processes - prevent spills - educate employees - reuse raw materials - substitute less-toxic - clean solvents

Precipitation

- also called flocculation, it binds the hazardous components of sewage to chemicals that chemicals clump and settle out

Recycling Hazardous Waste

- best applied to components that become hazardous waste when thrown away - upgrade a device rather than replacing

Toxic and Infectious

- can kill or cause serious harm to people and other organisms - these materials are separated into 3 categories Eg: - some medicines - blood products - pesticides - many household polishers and cleaners

Older Electronics

- contain polychlorinated biphenyls (PCB) which are extremely harmful chlorinated hydrocarbons. Like DDT, PCBs accumulate in animal tissue over time. They can harm immune, nervous, respiratory, reproductive and urinary systems. PCBs also cause cancer. - PCBs were banned in Canada in 1977. Any old electronics are likely to contain the material. PCBs continue to be a problem in developing nations.

Hazardous Waste in Municipal Solid Waste Landfills

- due to lack of knowledge, hazardous waste often ends up in municipal solid waste landfills. As a result, harmful substances may leach into liquids and travel into surrounding ecosystems

Reactive

- explode if improperly handled - react with other materials, air or water to produce harmful gases - destabilize with heat or shock Eg: - gunpowder - nitroglycerine - chlorine bleach - mixed with ammonia

Flammable and Combustible

- fire hazard if improperly handled - liquids release vapours - solids are unstable and could ignite or explode Eg: - Gasoline - paint thinner - kerosene - matches - napthalene

Immobilization

- fuses waste at high temperature for long-term storage

What is DDT and what are the problems with it

- have been linked to many health problems such as nervous system conditions, premature births, and reproductive problems in some animals and birds. The use of this pesticide was banned in 1970's and 1980's in most countries but it persists in the environment. It is still used in some countries to fight mosquitos that carry malaria

Reusing Hazardous Waste

- hazardous substance can be cleaned and reused by same industry for same process, different process by a different industry

2. Non-retrievable Storage: A Hazardous Waste Landfill

- hazardous waste landfill is lined with a impermeable plastic liner. - several layers of compacted clay to contain leachate - testing wells and monitoring underdrains check for escaped leachate - methane is collected

Corrosive

- materials that chemically destroy other materials, including metal and human skin - kept in containers made with special materials Eg: - Strong acids, such as hydrochloric acid and sulfuric acid - strong bases such as sodium hydroxide and calcium hydroxide

Governments at all levels set regulations and guidelines to

- oversee management of hazardous waste -protect workers who deal with waste - impose fines or penalties for those who do not follow the regulations

Biological Waste Treatment

- physical force or mechanical devices to reduce or remove contaminants(bioremediation) - degrades organic waste, eg. agricultural waste

Extended Producer Responsibility

- produce is responsible to recycle materials

Reducing waste at source

- reduce potential for accidental spill leaks from pipes and valves, broken containers - awareness training - use less hazardous substance

3. Retrievable Storage

- retrievable storage is more expensive - hazardous wastes are placed in containers in an accessible and secure location - waste can be removed and monitored easily

Stripping

- separates volatile chemicals from water and collects them

Collecting Hazardous Wastes

- waste depots, retailer drop off and municipal curbside collection programs

Thermal Waste Treatment

- waste to extreme heat making them less hazardous - reduces volume of waste

Treatment Hazardous Wastes

-Treating hazardous waste involves converting it to less hazardous substance and/or reducing its volume before disposal.

Phytoremediation

-bioremediation using plants such as in a wetland for sewage treatment

Chemical Waste Treatment

-converting hazardous waste into less hazardous substances - reduce volume

Environment Canada promotes a pollution prevention hierarchy which emphasizes reduction of hazardous waste according to the following strategy

1. Reduce the amount of waste at its source 2. Recycle wastes whenever possible 3. Treat waste to reduce their hazard or their volume 4. As a last resort, dispose of waste on land or incinerate them

At what points can hazardous substances enter the environment?

1. Research and Development 2. Manufacturing and importing 3. Storage 4. Transportation 5. Use 6. Disposal

What is Hazardous Waste?

A discarded substance(solid, liquid or gas) that is or contains a flammable, corrosive, reactive and or toxic substance.

Heavy Metals

Found in many products and can be hazardous as they accumulate in an organism. For instance, computers contain cadmium and mercury.

Disposal of waste in developing countries

In developing countries hazardous waste disposal is a problem. Poverty as well as lack of knowledge, may cause people to scavenge for materials to sell.

Hazardous Waste in medicine

Medical facilities such as hospitals, dental and veterinary practices produce biohazards such as blood products, used bandages, needles, and syringes. Both biohazards and radioactive waste disposal is managed under special government regulations.

What are hazardous substances found in?

Medicines, cleaners, pesticides and gasoline.

What is toxic waste?

Substances that are poisonous to organisms. They are a subgroup of hazardous substances.

Physical Waste Treatment

The use of organisms including microorganisms isolate hazardous wastes eg. filtration

Why do hazardous substances require special handling?

They cause harm to organisms and the environment

What happens if hazardous substances are not used up during their use or manufacture?

They will eventually enter the waste stream

How much hazardous waste do Canadians generate per year?

more than six million tons