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Hazardous Waste and Sanitary Landfills9/2/11

+What is an open dump landfill?

Open dump landfills are uncovered piles of solid waste.

They are more common in undeveloped countries.

+What are Sanitary Landfills? Solid wastes are spread into thin layers, compacted and covered daily with fresh clay or plastic foam to prevent leachate.

+What are the Pros and Cons of Sanitary Landfill?

Low operating Costs Can Handle Large

amounts of waste. Filled Land can be

used for other purposes.

There limited landfill space in many areas.

Noise, traffic, dustGreenhouse gasesOutput approach that

encourages waste reduction

Leachate – groundwater contamination

pros cons

+What is incineration? Burning trash

+What are the pros and cons of Incineration?

Reduces trash volume

Produces energyConcentrates

hazardous substances for burial

Sale of E reduces cost

ExpensiveProduces

hazardous wasteEmits air pollutants

Encourages waste production

pros cons

+What is hazardous waste? Any substance that is:

FlammableReactive Toxic Corrosive

+How can we detoxify hazardous waste? Physical methodsChemical methodsNanomagnetsBiological – bioremediation and phytoremediation

Plasma Arch torch

+What are the physical methods for detoxifying hazardous waste? Charcoal resins to filter solidsDistilling liquid wastes to separate out

harmful chemicals

+What are chemical methods to detoxify hazardous waste? Chemical reactions (i.e. neutralization) to convert hazardous chemicals to less harmful chemicals.

+What are nanomagnets?

Magnetic particles coated with compounds to remove various pollutants from water.

+What is bioremediation?

Use of biological agents, such as bacteria or enzymes to destroy toxins or convert them to less hazardous waste.

+What is Phytoremediation?

The use of naturally or genetically engineered plants to absorb, filter or remove contaminates from soil and water.

+What does a plasma arch torch do? Breaks down hazardous waste at very high temperatures.

+How can we store hazardous waste? Deep well disposalSurface impoundmentsAbove ground storage facilities

+What is deep well disposal?Hazardous wastes are pumped through a pipe full of dry, porous rock, where they soak into the rocks.

+What are the pros and cons of deep well disposal of Haz. Waste? Safe at certain

sitesWastes can often

be retrievedLow cost

Leaks from corrosion of well casing

Emits air pollutants

Encourages waste production

pros cons

+What are surface impoundments? Lined ponds, pits or lagoons in which liquid hazardous wastes are stored.

+What are the pros and cons of surface impoundments?

Low CostsWaste can often

be retrieved Can store wastes

indefinitely with secure double liners

Groundwater contamination from leakage liners and overflow

Air pollution from volatile organic compounds

Encourages waste production

pros cons

+FRQ check Annual precipitation at a landfill in the town of fremont is

100 mm per year, and 50 percent of this water runs off the landfill without infiltrating the surface. The landfill has a surface of 5,000 m2 . Underneath the landfill, the town installed a leachate collection system that is 80 percent effective. Any leachate not collected by the system enters the surrounding soil and ground water. This leachate contains cadmium and other toxic materials.

Calculate the volume of water in cubic meters (m3) that infiltrates the landfill per year.

+ 100 mm/year = 0.1 m/year 0.1 m/year x 5,000 m2 x 50% = 250 m3

So the volume of leachate in a m3 that is treated per year is

250 m3 x 80% = 200 m 3