Biomass
Composition of Municipal Solid Waste
Energy Retrieval from Recycling
Incineration and Incinerator Ash
Secure Landfills
Efficiency of Conversion of Sunlight into Biomass
Methane Digesters
Alternative Biomass Fuels for Vehicles
Wood Combustion
Energy Plantations

Energy in the News

Composition of Urban Garbage
William Rathje
Garbologist
When did Arizona
Residents throw out the most meat?

Composition of Solid Waste: 23 Cities

Waste Generation Rates over Time

Changes in Disposal Methods

Energetics of Recycling and Substitution
Energy Cost of Various Materials
Paper Cups
Steel from Ore
Aluminum from Ore
Copper from Ore
Glass from Ore
36 Styrofoam Cups
23 Steel From Scrap
43 Aluminum from Scrap
4.3
1.3
Copper from Scrap
Glass from Cullet
1
1
1
1
1

Biodegradability
Biodegradability in garbage dumps: an non-issue.
Rapid biodegradation: requires oxygen and/or water.
Rathje:perfectly preserved years old meat and vegetables!

Waste to Energy Plant
Locked into long term contract: may discourage recycling
Fly ash: Bottom ash: Where collected and transported?

Metal in Incinerator Ash
Fly ash: from electrostatic precipitators. Bottom ash: bottom of boiler
Which is most dangerous??
Additional concerns: dioxin from burning of chlorine containing compounds (plastics,etc.). Dioxin: carcinogen, endocrine disrupter

Recycling Trivia
Americans consume 2.5 million plastic bottles every hour
If you drink 2 cans ofsoft drink per day in aluminum cans and cans are not recycled,you waste more energy than is used daily by one human in the lesser developed countries
Recycling one aluminum can saves enough energy to run a TV for 3 hours
Recycling of all paper used in the Sunday edition of the New York Times would save 75,000 trees per year

Fly Ash Dump in Korba India
(from power plant)
No vegetation.

Fly Ash Dump in Badarpur, India
Reclaimed using mycorrihizal fungi (bioremediation)
Also small amounts of compost.
Reduces air pollution from fly ash dump.

Secure Landfill Black layers on top and bottom: liner
Liner thickness: about 1/3 inch
Circles on bottom: leachate pipes
Note: Gas vent, low permeability soil, filter layer, barrier layer, drainage layer

Percent Trash Disposal in Landfills

Biomass Production vs Energy Use
Uses of biomass
Aside from energy?

Biomass to
Fuel
Conversions
Results:
Alcohol (Ethanol)
Biogas (Methane)
Syngas
Gasoline (Biocrude)
Diesel Fuel (Plant Oil)

Methods of Biomass to Energy
Conversion
Direct combustion
Pyrolysis: thermal decomposition into gas or liquid
Involves high temperatures (500-900°C), low oxygen
Biochemical processes:
Anaerobic digestion by methanogens
Controlled fermentation produces alcohols:
Ethanol (grain alcohol)
Methanol (wood alcohol)

Anaerobic Digester
Converts animal or plant waste
Into methane
Typical wastes:
Manure (feed lots,pig farms, poultry)
Olive oil mill waste
Potato processing waste
Big deal: Agricultural Science Depts

Optimum Operating Temperature
35°C, maximum liters of methane per day, best retention time?

Cellulose High Solids Fermenter
Adjusting agitator shaft of high solids fermenter. Produces methane gas, high quality compost from sewage sludge, use 1/20th the water
Compared to conventional digesters. Downside: agitator needed.

Energy Used to Grow vs Food Energy
Ethanol from corn: 1.74 per gallon to produce vs 95 cents per gallon
Of gasoline.
70% more energy to make ethanol from US corn than energy in ethanol
Good use of ethanol: oxidizer to replace MTBE in gasoline
10% ethanol boosts octane rating of gasoline, replaces lead.

Energy Contributions to Bread Loaf
Grain production, Baking, Transport, Milling, Shops, Packaging

Energy in Biomass
Only a small amount energy in sunlight converted into biomass by plants.
Conversion efficiency varies:
Sugar cane: 2%
Corn: 1%
Typical forest: 0.8%
Most food plants: <0.8%
Maximum theoretical efficiency: 10%

Sugar Cane
Sugar cane: very high productivity per acre. Use bagasse
(sugar cane waste) to run boilers to boil sap for sugar.
Bagasse to energy plants: 7% of Hawaiian energy
(Mauritius)

Bagasse to Methane Plant: Hilo, HI

Hemp Plants
Advantages: 4 times as much pulp per acre as wood, no pesticides needed
Can make cloth,rope paper. Does need nitrogen fertilizer.
Not good to smoke. 1763-1767-Virginia farmers jailed if no hemp grown.

Four Year Old
Eucalyptus: Hawaii
Eucalyptus: produce high amounts
Of biomass under drier conditions
Than hemp. Very hardy species.

Plants as Sources of Petroleum
Like Substances
Gopher plant: grows wild in California: 25 barrels of crude oil per hectare
Copaifera multijuga: found in Brazil: produces almost pure diesel fuel
Bladderpod: can be used to make plastic
Jojoba: 50% oil by weigh: resembles sperm oil: doesn’t go rancid

Plastics Made from Pyrolysis Oil
(Wood Chip Waste)

Low Cost, Efficient Woodstoves
A India, B. Nepal C. Guatemala,
Most of the world cooks with wood. Typical wood stove:
Only 10% efficient. Time to collect wood: 2 to 5 hours per day.
80% of fuel use in developing world; wood for cooking.
Major cause of deforestation, soil erosion.

Comparable Efficiency Values
Efficiency: multiply by 100.

Rocket Stove vs Three Stone Fire
Rocket Stove: insulated fire box, short chimney, cooks on top of
Chimney, skirt surrounds pot. Built in Guatemala.

Rocket Stove

Addition of Haybox
Haybox: insulated box. Food placed in box and left once water heated to boiling point. Food continues to cook without fire. (Why?)

Air Tight
Stove
Stove has lower chamber
With burning wood,
Upper chamber with
Secondary combustion
Long path for exhaust gas
= more complete burning
Note high surface area of
Stove.
About 50% efficient