i. i.solid wastes b. b.alternatives 3. 3.composting removing metal and newspaper aerobic –...

I. Solid Wastes

B. Alternatives3. Composting

• Removing metal and newspaper• Aerobic – Decomposition with frequent agitation

(faster)• Anaerobic – Decomposition without agitation

(slower)

Source: EPA

I. Solid Wastes

B. Alternatives3. Composting

• Pro: • Decreased volume of waste• Compost useful for mulch, lightening soil, improved

water retention• Anaerobic decomposition methane that can be

harvested as an energy source• Con:

• Requires processing in preparation for composting• Requires attention to maintain aerobic conditions

• Anaerobic decomposition is slow• Methane generation is hazardous (fire risk)• Methane is a GHG

I. Solid Wastes

B. Alternatives4. Incineration

• Used extensively in Europe• Increasingly common in US, especially where other

options are limited (e.g. Northeast)• Large municipal incinerators

Source: EPA

I. Solid Wastes

B. Alternatives4. Incineration

• Pro: • Reduces waste volume up to 90%• Can generate electricity (“Waste To Energy”)

• Con: • Air pollution – hard to anticipate pollutants

from combustion of waste (esp. plastics, etc.)• Expensive emissions control equipment

required• Waste ash still requires disposal

Source: EPA

Source: EPA

Source: EPA

II. Energy

US EIA

• World energy consumption projected to rise 53% from 2008 to 2035

• Greatest projected increase in non-OECD countries (85% vs. 18% in OECD countries)

• What is the OECD?

II. Energy

• Energy use in non-OECD Asia (incl. India & China) to more than double by 2035

US EIA

II. Energy

A. Conventional1. Fossil Fuels

a. Oil• Transportation, electricity generation, heating• World’s dominant source of energy for past

several decades• Expected to remain important for next 20 years

- Predicted change: 3429% of total energy consumption through 2035

• Greatest consumption by OECD nations, but gap closing

• 1999 – Non-OECD nations consumed 58% as much as OECD nations

• 2030 – Projected to use ~90% as much• Most of increase from transportation sector

(few alternative fuel sources)

II. Energy

A. Conventional1. Fossil Fuels

a. Oil• Benefits

• Readily available• High energy density• Inexpensive• Existing technology & infrastructure

• Concerns• Combustion releases pollutants (CO2, NOx,

SOx, PM)• Extraction harms environment• Accidental releases, especially in ocean• Energy security – US imports 60% of oil• Long-term availability (unconventional sources)

Unconventional Sources• Oil sands• Extra-heavy oil• Coal-to-liquids• Gas-to-liquids• Shale oil• Biofuels

US EIA

II. Energy

A. Conventional1. Fossil Fuels

b. Coal• Electricity generation (60% of global coal use, 2008)• Main fuel source in China for industry• Use expected to grow, mostly fueled by Asia,

especially China (78% of global growth) and India• Benefits

• Inexpensive• Abundant, easy to recover• Requires minimal processing• Existing technology & infrastructure

• Concerns• Environmental degradation from mining• Requires extensive transportation system (rail)• Combustion pollutants (CO2, PM, Hg, NOx, SOx)• Counter: “Clean coal” (requires more processing)