Unit C: Topic 6Unit C: Topic 6

NIMBY: Not In My Back YardNIMBY: Not In My Back Yard

Producing WastesProducing Wastes

Since the industrial revolution, Since the industrial revolution, the amount of wastes being the amount of wastes being produced has been increasing.produced has been increasing.

More wastes means more More wastes means more landfills but no one wants a landfills but no one wants a landfill in their neighborhood.landfill in their neighborhood.

The Movement of PollutionThe Movement of Pollution Pollution can be produced in one Pollution can be produced in one

area but transported to other places area but transported to other places in the world.in the world.

There are three stages of transport There are three stages of transport of pollutants:of pollutants:

1. Release of chemicals at the source.

2. Dispersion of the chemical into the atmosphere.

3. Deposition of the chemical in soil or water.

The direction and distance of The direction and distance of airborne pollutants depends on airborne pollutants depends on various factors including:various factors including:

1. The type of pollutant.1. The type of pollutant. 2. The wind speed.2. The wind speed. 3. The direction of the winds.3. The direction of the winds. 4. The speed and direction of 4. The speed and direction of

ocean currents.ocean currents.

Natural Vs. Man-Made Natural Vs. Man-Made WastesWastes

Natural wastes include volcanic Natural wastes include volcanic ash, forest fires, animal and ash, forest fires, animal and plant wastes.plant wastes.

Man-made wastes include toxic Man-made wastes include toxic chemicals, airborne pollutants, chemicals, airborne pollutants, etc.etc.

CFCs and the Ozone LayerCFCs and the Ozone Layer

CFCs = chlorofluorocarbons. CFCs = chlorofluorocarbons. They are produced by They are produced by refrigerant coolants and aerosol refrigerant coolants and aerosol cans as well as in Styrofoam. cans as well as in Styrofoam.

One chlorine atom from a CFC One chlorine atom from a CFC molecule can break up 100’000 molecule can break up 100’000 ozone molecules (Oozone molecules (O33).).

International agreements have International agreements have been signed to limit the been signed to limit the production of CFCs.production of CFCs.

Surface Water PollutionSurface Water Pollution

Most comes from clothes Most comes from clothes washing which pollutes the washing which pollutes the water with nitrates and water with nitrates and phosphates.phosphates.

Sewage treatment involves Sewage treatment involves removing harmful levels of these removing harmful levels of these chemicals.chemicals.

Septic TankSeptic Tank

Underground tank that traps Underground tank that traps grease and solid wastes.grease and solid wastes.

The remaining liquid waste are The remaining liquid waste are pumped into a field where pumped into a field where bacteria can break down the bacteria can break down the waste products leaving water for waste products leaving water for irrigation and the waste as irrigation and the waste as fertilizers. fertilizers.

Treating Sewage – A 3 Step Treating Sewage – A 3 Step ProcessProcess Primary Treatment – Physically Primary Treatment – Physically

separating large solids and separating large solids and sedimentssediments

Secondary Treatment – Removing Secondary Treatment – Removing organic compounds by bacterial organic compounds by bacterial decomposition. UV light or chlorine is decomposition. UV light or chlorine is used to kill germs.used to kill germs.

Tertiary Treatment – Chemicals such Tertiary Treatment – Chemicals such as phosphates and nitrates are as phosphates and nitrates are removed from water which is passed removed from water which is passed into soil as ground water.into soil as ground water.

Ground WaterGround Water

Water that filters down through Water that filters down through soil. It moves average 15 m/a.soil. It moves average 15 m/a.

The more permeable the soil, The more permeable the soil, the faster the flow rate of ground the faster the flow rate of ground water.water.

Impermeable bedrock and clay Impermeable bedrock and clay prevent ground water from prevent ground water from moving.moving.

AquifersAquifers

Underwater pools which serve Underwater pools which serve as supplies of spring water. as supplies of spring water. Water here is filtered naturally Water here is filtered naturally and free from bacteria and free from bacteria contamination.contamination.

However as ground water However as ground water becomes polluted so do aquifers becomes polluted so do aquifers and water contamination here is and water contamination here is nearly irreversible.nearly irreversible.

BiodegradableBiodegradable

Organic substances which can Organic substances which can be broken down naturally by be broken down naturally by organisms or common organisms or common chemicals (eg. water, air).chemicals (eg. water, air).

In order for biodegradation to In order for biodegradation to occur, the waste must be mixed occur, the waste must be mixed in with water, organisms, and in with water, organisms, and air; conditions that aren’t met in air; conditions that aren’t met in most landfills.most landfills.

Sanitary LandfillsSanitary Landfills

Most commonMost common Waste is buried daily under dirt.Waste is buried daily under dirt. Clay lines the bottom to prevent Clay lines the bottom to prevent

contamination of groundwater. contamination of groundwater. Liquid waste, Leachate, is sent Liquid waste, Leachate, is sent to water treatment center.to water treatment center.

Hazardous by-products such as Hazardous by-products such as methane are produced methane are produced anaerobically.anaerobically.

Secure LandfillsSecure Landfills

Used for toxic wastes.Used for toxic wastes. Clay lining is backed up with Clay lining is backed up with

gravel, plastic layers and drain gravel, plastic layers and drain pipes to collect toxic seepage.pipes to collect toxic seepage.

When filled, the waste are When filled, the waste are capped by layer of clay, plastic, capped by layer of clay, plastic, and soil.and soil.

The landfill is forever monitored The landfill is forever monitored for toxic leaks through the for toxic leaks through the drilling of wells.drilling of wells.

The (Second) Last SlideThe (Second) Last Slide Bioremediation – The use of Bioremediation – The use of

living things instead of living things instead of synthetics to fix a problem. Eg. synthetics to fix a problem. Eg. Using plants to remove heavy Using plants to remove heavy metals from soils, and ladybugs metals from soils, and ladybugs as pesticides.as pesticides.

Bioreactors – Using bacteria Bioreactors – Using bacteria holding tanks as natural sanitary holding tanks as natural sanitary landfills. Bacteria break down landfills. Bacteria break down organic wastes in the presence organic wastes in the presence of air and water.of air and water.

Phytoremediation andPhytoremediation and

Phytoremediation: a technique that can be used to reduce the concentration of harmful chemicals in the soil or groundwater. Plants have been used to clean up metals and other pollutants. The plants are able to absorb and accumulate large amounts of these chemicals. When the plants have matured, they are harvested, burned or composted.

Other plants can then be grown in the healthier soil.

PhotolysisPhotolysis

Photolysis is the breakdown of compounds by sunlight. The formation of ozone is an example of this process

Another example is photodegradable plastic. This plastic is made of chemicals that react when exposed to sunlight. In 3 months, the plastic becomes a fine powder that is easier to dispose of. (This type of plastic will only degrade if it is exposed to sunlight – if it is buried, it will last in its original shape for hundreds of years.)