BiomassComposition 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 RathjeGarbologist

When did ArizonaResidents throw outthe 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 36 Styrofoam Cups 1

Steel from Ore 23 Steel From Scrap 1Aluminum from Ore 43 Aluminum from Scrap 1

Copper from Ore 4.3 Copper from Scrap 1Glass from Ore 1.3 Glass from Cullet 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 recyclingFly ash: Bottom ash: Where collected and transported?

Metal in Incinerator Ash

Additional concerns: dioxin from burning of chlorine containingcompounds (plastics,etc.). Dioxin: carcinogen, endocrine disrupter

Fly ash: from electrostatic precipitators. Bottom ash: bottom of boilerWhich is most dangerous??

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: linerLiner thickness: about 1/3 inchCircles on bottom: leachate pipesNote: Gas vent, low permeability soil, filter layer, barrier layer, drainage layer

Percent Trash Disposal in Landfills

Biomass Production vs Energy UseUses of biomassAside from energy?

Biomass to Fuel

Conversions

Results:Alcohol (Ethanol)Biogas (Methane)SyngasGasoline (Biocrude) Diesel Fuel (Plant Oil)

Methods of Biomass to Energy Conversion

Direct combustion

Pyrolysis: thermal decomposition into gas or liquidInvolves high temperatures (500-900°C), low oxygen

Biochemical processes: Anaerobic digestion by methanogensControlled fermentation produces alcohols:Ethanol (grain alcohol)Methanol (wood alcohol)

Anaerobic Digester

Converts animal or plant wasteInto methane

Typical wastes:Manure (feed lots,pig farms, poultry)Olive oil mill wastePotato processing waste

Big deal: Agricultural Science Depts

Optimum Operating Temperature35°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 gallonOf gasoline. 70% more energy to make ethanol from US corn than energy in ethanolGood use of ethanol: oxidizer to replace MTBE in gasoline10% ethanol boosts octane rating of gasoline, replaces lead.

Energy Contributions to Bread LoafGrain production, Baking, Transport, Milling, Shops, Packaging

Energy in BiomassOnly 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 PlantsAdvantages: 4 times as much pulp per acre as wood, no pesticides neededCan 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 amountsOf biomass under drier conditionsThan 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 WoodstovesA 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 ValuesEfficiency: multiply by 100.

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

Rocket Stove

Addition of HayboxHaybox: 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 chamberWith burning wood,Upper chamber with Secondary combustionLong path for exhaust gas= more complete burningNote high surface area ofStove. About 50% efficient