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Composts

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Composts How to use a compost tumbler (2:05) https://www.youtube.com/watch?v=m1Q5bVt8wLg Everything you should know about composting TEDx (17:21) – PowerPoint PPT presentation

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Title: Composts


1
Composts
  • How to use a compost tumbler (205)
  • https//www.youtube.com/watch?vm1Q5bVt8wLg
  • Everything you should know about composting TEDx
    (1721)
  • take notes while viewing, then get into groups
    and make a step-by-step procedure for composting.
  • https//www.youtube.com/watch?vn9OhxKlrWwc
  • Compost with fall leaves, farm with cover crop
    (957)
  • https//www.youtube.com/watch?vn695v0kYOG8

2
Composts
  • What is compost and why use it?
  • What organisms are involved in the composting
    process?
  • What chemical changes occur during composting?
  • What are the optimal conditions for composting
  • Temperature
  • Moisture
  • Oxygen
  • Does composting kill harmful pathogens (plant and
    human), nematodes and weed seeds?
  • Safety regulations
  • Compost production systems
  • Small scale
  • Commercial

3
What is compost why use it?
Composting is the decomposition of plant remains
and other once-living materials to make an
earthy, dark, crumbly substance that is excellent
for adding to houseplants or enriching garden
soil.
  • compost improves soil structure, texture,
    aeration - increases the soil's water-holding
    capacity.
  • Compost loosens clay soils and helps sandy soils
    retain water.
  • improves soil fertility and stimulates healthy
    root development
  • Organic matter provides food for microorganisms -
    nitrogen, potassium, and phosphorus mineralized

4
The Science of Composting
  • Composting is the natural process in which living
    organisms decompose organic matter into inorganic
    matter in the soil.
  • The organisms feed on the organic material and
    through respiration generate the energy that they
    use for movement, growth, reproduction or stored
    energy.
  • The organism excretes inorganic material that
    enriches the soil.
  • When the organisms die, their bodies add to the
    organic matter in the compost pile.

5
Fresh Organic Materials
Oxygen

Microbes, Moisture, and Time
Compost
Energy
Carbon Dioxide


Slide credit Tom Richard, Penn State University
6
Organisms use carbon as a source of energy and
nitrogen to grow and reproduce.
  • Too little N
  • there will be few microorganisms, and
    decomposition will be slow.
  • Too much N
  • some will turn to ammonia that will volatilize,
    creating an odor.

7
Experimental test - effect of CN ratio on
nitrogen retention in compost

Initial CN ratio Final nitrogen Nitrogen conservation

1 20 1.44 61.2
2 20.5 1.04 51.9
3 22 1.63 85.2
4 30 1.21 99.5
5 35 1.32 99.9
8
Factors affecting the compost process
CN ratio
Size and texture
Aeration
NB. Moisture level also critical
9
Moisture level is also critical
  • Optimum moisture content 40-60
  • Feels moist to touch, but when squeezed only
    produces few drops

10
Ideal conditions for composting
11
The Science of Composting
  • Composting goes through three distinct phases
    that can be characterized by temperatures.
  • Mesophilic Phase (moderate temperature)
  • Thermophilc Phase (high temerpature)
  • Mesophilic Phase (moderate temperature again)

12
The Science of Composting
  • Mesophilic Phase 1 (10-40 0 C)
  • Lasts only a few days
  • Explosive growth of bacteria and fungi
  • Rapid breakdown of soluble sugar and starches
  • Thermophilic Phase (gt40 0 C)
  • Can last from several days to several months
    depending on size of system
  • Mixed population of heat loving organisms
  • High heat helps breakdown of proteins, fats,
    tough plant material like cellulose
  • High temperature (gt55 0C) kill weeds and pathogen
    harmful to humans
  • Higher temperature (gt600C) kill organism needed
    for decomposition
  • Mesophilic Phase 2 (10-40 0 C) Curing Phase
  • Can last several months
  • Bacteria, fungi, actinomycetes( mix between
    bacteria and fungus, give earthy smell)
    predominate. Invertebrates active.
  • Supply of organic material has decreased.
    Remaining organic material is slowly broken down.
  • Additional chemical reactions take place to make
    remaining organic material more stable

13
The Science of CompostingChemistry
  • Important factors in compost chemistry
  • Carbon-Nitrogen Mix (C/N Ratio)
  • Carbon provides energy source and building
    material for 50 of composting organisms cells
  • Nitrogen important in formation of proteins,
    nucleic acids, amino acids, enzymes etc. for
    organisms
  • 301 Carbon to Nitrogen optimum mix (decreases in
    curing phase)
  • Brown and woody? carbon
  • Green and moist? nitrogen

14
The Science of CompostingChemistry
  • Important factors in compost chemistry
  • Oxygen
  • Needed to oxidize carbon for energy
  • Without oxygen will produce rotten egg smell
  • pH Level
  • Acids form as organisms digest organic material
    and lowers pH
  • Lower pH encourages fungi and the break down of
    tough matter
  • If pH too low (lt4.5) limits microorganisms
    activity

15
Changes in Ammonium-N distillation method fresh
sample
16
Changes in Carbon to Nitrogen Ratio
Dan Sullivan and Linda Brewer
17
Changes in cation exchange capacity(ash-free pH
7)
18
Temperature
Fatty acids
NH3 emitted
pH
days
19
Compost chemistry - pH
20
The Science of CompostingPhysics
  • Important factors for compost physics
  • Temperature
  • 3 Phases
  • Want to maintain temperature between 55-600C
  • Temperature impacted
  • Heat generated by organism
  • Heat lost to environment through conduction,
    convection and radiation ? shape and size of pile
  • Moisture content (specific heat and heat capacity
    of water)

21
The Science of CompostingPhysics
  • Important factors for compost physics
  • Particle size
  • Microorganism activity occurs on surface of
    organic material
  • The more surface area for organisms to attack,
    the quicker the decomposition ? want smaller
    particles
  • Flip-side The smaller the particles, the more
    dense and compact the material resulting in poor
    oxygen circulation

22
The main players
  1. Bacteriamajor decomposers, breakdown simpler
    forms of organic material
  2. Actinomycetesdegrade complex organics such as
    cellulose, lignin, chitin, and proteins earthy
    smell, long spider webs filaments
  3. FungiBreak down tough debris, too dry, too
    acidic or too low in nitrogen for bacteria to eat

23
What do microbes in compost do?
  • Consume organic matter to grow
  • Stabilize organic matter
  • Aerobic oxidation produces CO2
  • Anaerobic produces reduced compounds organic
    acids, alcohols
  • Mineralize nutrients
  • Organic to inorganic forms (protein to NH4)
  • Transform nutrients
  • Nitrification pH and temperature sensitive
  • NOTE invertebrates not important in high
    temperature composting, only in cold

24
Compost Quality
  • Compost Maturity and Nitrogen Release
    Characteristics in Central Coast Vegetable
    Production
  • July 2002
  • CA Integrated Waste Management Board
  • Marc Buchanan, PhD

25
Compost Maturity
26
Compost Maturity
27
Compost Quality Measures
CN below 25
28
COMPOST QUALITY INDEX for Commercial
Products Based on 13 monthly samples for green
waste, 11 for blend, and 1 poultry manure compost.
29
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30
Inorganic N release Spring and summer 2000
31
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32
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33
Growing Issue
  • How effective is composting at killing pathogens?
  • Weeds, plant disease organisms
  • Human pathogens!!!!

34
U.S.A. Composting Regulations
  • Biosolids, Class A compost (U.S. EPA 40 CFR Part
    503)
  • Time-temperature relationship (PFRP)
  • Static aerated pile, 3 days gt 55 C
  • Turned windrow, 15 days gt 55 C, turned at least
    5 times
  • Vector Attraction Reduction
  • 14 days, 40 C minimum, 45 C average temperature
  • Pathogen testing criteria
  • Fecal Coliforms lt 1000 MPN/g TS
  • or Salmonella lt 3 MPN/4g TS
  • USDA National Organic Program 205.203 (c)
  • Time temperature 55 C 70 C (CFR Part 503)
  • Turned windrow 15 days with at least 5 turns
  • In-vessel or static aerated system 55 C 70 C
    for 3 days
  • CN ratio 251 401 (NRCS code 317 composting
    facility)

35
  • Why turn windrows at least 5 times in 15 days?
  • Prevent regrowth of Salmonella
  • Non-uniform heating
  • Turn cooler material into insulated center

gt 55 C
Done properly it works, but can less intensive
regimes work too?
36
NOSB Compost Task Force
  • Composting regulations too prescriptive
  • Manage compost to reach 55 C for 3 days
  • Vermicompost
  • Aerobicity maintained by adding thin layers every
    1-3 days
  • 70-90 moisture
  • 12 months for outdoor windrows, 4 months for
    wedge systems or indoor containers, 2 months for
    vertical flow reactors
  • Processed manure
  • Heat to 65 C for 1 hour
  • Dry to lt 12 moisture
  • Negative for Salmonella and fecal coliforms

37
Animal pathogen destruction
  • Meet current time-temperature standards
  • Will not eliminate all weed seeds or all plant
    pathogens
  • Attain sanitation target for particular end-use,
    quality assurance testing
  • Use technology that is financially attainable
  • Composting process
  • Contain and treat leachate
  • Exclude vectors
  • Avoid pathogen regrowth conditions
  • Avoid recontamination of product

38
Compost production systems
  • Small scale

Compost piles need to be at least one cubic to
hold the heat from decomposition
39
Passive composting
40
Commercial composting
  • Large scale
  • Passive aeration with turning or actively aerated
    systems

41
Feedstock conditioning - grinding
42
Moisture management - most important factor to
stabilize biological and chemical properties
43
Processing turned windrows
44
Compost blankets to moderate moisture
www.vanierselcompost.com/. ../productie.htm
45
Composting - windrow
Turning helps aeration and to move material from
edge into hot center region
CO2
Hot
O2
Cool
Graphic credit Tom Richard, Penn State
University
46
Composting Static forced air
CO2
  • Air forces heat outwards
  • Some systems can switch direction to keep base
    core at high enough temperature
  • Also helps control odor

Hot
O2
Cool
Graphic credit Tom Richard, Penn State
University
47
Processing - forced aeration
48
Hot ammonia kills!!!

49
Contain, treat leachate
50
Compost blankets beware moving from fresh to
curing
www.vanierselcompost.com/. ../productie.htm
51
Cure compost with 40-50 moisture to promote
competitive microorganisms and avoid salmonella
regrowth
52
CASFS Farm compost piles 2008
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