Decay and Renewal

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Decay and Renewal

• Harnessing Natural Decay

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Human waste Disposal Processes

• In New York City in the 1800s
• Streets had trash human and animal wastes
• Bodies of dead horses
• Pigs eating and leaving waste
• Air smelled like bad eggs dissolved in ammonia

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Human waste Disposal Processes

• By 1910 most US cities had some form of trash and
  waste disposal.
• But waste wasnt treated.
• Until 1965 raw sewage was dumped into water ways
  or ocean.
• After WWII plastics became a waste problem.

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Biodegradable Plastics

• Cellophane first artificial packing material
• made from wood pulp
• Widely used until 1930s
• Biodegradable
• Polystyrene not biodegradable
• Some new plastics are degradable.

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Landfills

• 2000 in US
• 230 millions tons of solid waste
• 4.5 lbs/person/day
• 55 goes to landfills

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Data as of 2000
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Landfills

• 70 biodegradable
• Paper, food, yard waste
• 30 resistant to decay
• Metal, plastics, glass, etc.
• Decay slow
• Landfill oxygen levels very low
• Retards decay
• Produce methane

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Landfills
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2 Types of Bioreactor Landfills

• Methane Generator landfills
• Low-oxygen
• Produces methane from microbes for energy
• Composting Landfills
• Adds moisture and oxygen
• Careful mix of materials
• Faster decay

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Composting

• Definition The process of decomposing organic
  materials under controlled conditions.
• Recycles nutrients and minerals back to the soil.
• Speeds up decay.
• Optimum conditions for microbes of decay.

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Compost Biology

• Macroinvertebrates
• Worms

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Compost BiologyMillipedes
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Compost Biology Sow bugs
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Compost Biology

• Bacteria
• Majority of decomposition
• Heat generation in compost
• Produce enzymes that break down organic materials

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Compost Biology

• Actinomycetes
• Filament (string-like) bacteria.
• Earth (dirt) smell
• Break down cellulose in wood

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Compost Biology Actinomycetes
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Compost Biology Fungi

• Mold, Yeast, Mushrooms
• Breakdown materials that bacteria cant
• Dry
• Acidic
• Low in nitrogen
• Allow bacteria to digest whats left

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Compost Chemistry and Physics

• Compost Microbes Need
• Carbon for energy
• Nitrogen to build proteins
• Oxygen for respiration
• Moisture to support life
• Heat (up to 65C)

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Compost Chemistry and Physics

• Ideal Carbon to Nitrogen Mix (CN)
• 301
• Colorful wastes tend to be high in Nitrogen and
  low in Carbon
• Brown wastes like
• wood chips, Straw, cardboard, brown leaves
• Low nitrogen, High carbon

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Compost Chemistry and Physics

• Best compost equal mix
• Colorful moist
• Dry brown
• Watch temp.
• Mix to stir in new food

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Compost Chemistry and Physics
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Compost Chemistry and Physics
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Wastewater Treatment