Unit 8: (8.9) Solid Waste Disposal

MSW (municipal solid waste)

refuse (garbage, litter, trash) collected by municipalities (cities) from households, small businesses, and institutions

refuse

something discarded; trash

municipality

A city, town, etc.

sanitary landfill

a clay or plastic-lined landfill that holds nonhazardous waste such as municipal solid waste and construction debris.

Leachate

polluted water that has percolated through waste in a landfill and leached out some of the harmful chemicals. Ex: mercury, lead, battery acid, bacteria

leachate collection system

A system of pipes beneath a landfill that collects fluid that leaches from the trash. Harvested and treated to reduce groundwater cont.

methane collection system

A system of pipes that collects methane gas that is formed during the anaerobic (no oxygen) decomposition of trash in a landfill. Prevents explosions and reduces total volume of MSW in the landfill. Can also be burned to create electricity in a Natural Gas power plant

anaerobic decomposition

decomposition that occurs without using, or in the absence of, oxygen. Happens in capped landfills and produces methane.

waste incineration

The burning of MSW, primarily to reduce the volume going into the landfill and extend the lifetime of landills. Secondarily, it can be used to generate electricity in a waste-to-energy facility (same process as nuclear or FF electricity gen.)

Disadvantages of waste incineration

NIMBY: Can produce PM and NOx emissions, lowering air quality
Produces highly concentrated, toxic ash contaminated with mercury, cadmium, lead
Releases GHGs: CO2 and Nitrous oxide (N2O)

Ocean dumping

the deliberate (purposeful) dumping of trash & wastes into the ocean. Typically in countries with lax env. regulations & laws. Leads to solid waste pollution.

Landfill disadvantages

Produce lots of methane, which is often just vented into atmosphere (GHG & glob. warm.)
Leachate can cont. groundwater with heavy metals
NIMBY: Can attract animals during use & cont. nearby ground water even after capped
Very costly to produce & run. Managers charge a tipping fee ($/ton) of waste dumped in landfills
Little to no decomposition due to anaerobic conditions