633160751-composting on the river gangas

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1. COMPOSTING
(Managing Organic Wastes )

2. PRINCIPLES OF
COMPOSTING

3. What Is Compost?What Is Compost?
The product resulting from the controlled biological
decomposition of organic materials
Sanitized through the generation of heat
Stabilized to the point where it is beneficial to plant
growth
Provides humus, nutrients, and trace elements to soils
Organic Materials
Landfill wastes (food, wood, textiles, sludge etc.)
Agricultural wastes (plant or animal)
Industrial manufacturing byproducts
Yard trimmings
Seafood processing wastes
In short, anything that can be biodegraded

4. Why Compost?Why Compost?
40–85% of solid waste in INDIA is organic (National
Solid Waste Association of India, 2003)
12% of landfilled solid waste is food wastes /
discards
Agricultural wastes  potential for nutrient pollution
Yard wastes – banned from landfills
Compost benefits to soil – 25 lbs N, 13 lbs P (as
P
2O
5) and 7 lbs K (as K
2O) per ton of compost
Environmental sustainability

5. The Composting ProcessThe Composting Process
Biological decomposition in aerobic environment
Decomposition & mineralization by microbes
Bacteria, actinomycetes, fungi, protozoans, nematodes
Food source – Nitrogen (biodegradable organic matter)
Energy source – Carbon (bulking agent)
Outputs
Heat
Water Vapor
Carbon Dioxide
Nutrients and minerals (compost)
Process occurs naturally, but can be accelerated by
controlling essential elements

7. Composting Essential ElementsComposting Essential Elements
Nutrients
Carbon/Nitrogen (C/N) – 20:1 to 35:1
Carbon/Phosphorus (C/P) – 100:1 to 150:1
Moisture Content – 50% to 60% (wet basis)
Particle Size – ¼” to ¾” optimum
Porosity – 35% to 50%
pH – 6.5 to 8.0
Oxygen concentration - >5%
Temperature – 130
o
F. to 150
o
F.
Time – one to four months

8. Nutrient Balance in CompostingNutrient Balance in Composting
C/N ratio – target is 30:1
> 30:1 – not enough food for microbial population
< 30:1 – nitrogen lost as ammonia (odors)
Sources of N & P - Organic wastes, manures, sludge, etc.
Sources of C – wood wastes, woodchips, sawdust
Example C/N Ratios:
Food waste 14 – 16 : 1
Refuse/trash 34 –80 : 1
Sewage sludge 5 –16 : 1
Corrugated cardboard 563 : 1
Telephone books 772 : 1
Mixing components needed to optimize C/N ratio

9. Moisture ContentMoisture Content
Source of nutrients for microbial protein synthesis and growth
Optimum water content – 50% to 60% (wet weight basis)
< 50% - composting slows due to microbial dessication
> 60% - compaction, development of anaerobic conditions,
putrefaction/fermentation (odors)
Water may be needed during mixing, composting
Yard wastes – 40 to 60 gallons per cubic yard
Typical moisture contents
Food wastes 70%
Manures and sludges 72% - 84%
Sawdust 19% - 65%
Corrugated cardboard 8%
Newsprint 3% - 8%

10. Particle Size & DistributionParticle Size & Distribution
Critical for balancing:
Surface area for growth of microbes (biofilm)
Adequate porosity for aeration (35% - 50%)
Larger particles (> 1”)
Lower surface area to mass ratio
Particle interior doesn’t compost – lack of oxygen
Smaller particles (< 1/8”)
Tend to pack and compact
Inhibit air flow through pile
Optimum size very material specific

11. pHpH
Optimum range 6.5 – 8.0
Bacterial activity dominates
Below pH = 6.5
Fungi dominate over bacteria
Composting can be inhibited
Above pH – 8.0
Ammonia gas can be generated
Microbial populations decline

12. Porosity and AerationPorosity and Aeration
Optimum porosity 35% - 50%
> 50% - energy lost is greater than heat produced lower
temperatures in compost pile
< 35% - anaerobic conditions (odors)
Aeration
Controls temperatures, removes moisture and CO
2 and provides
oxygen
Airflow rate is directly proportional to the biological
activity
O
2
concentration < 5% - anaerobic conditions

13. Time and TemperatureTime and Temperature
Temperature is key process control factor –
monitor closely
Optimum temperatures: 130
o
F. – 150
o
F.
Temperatures above 131
o
F. (55
o
C.) will kill
pathogens, fecal coliform & parasites
Optimum temps achieved by regulating airflow
(turning) and/or pile size

14. COMPOSTINGCOMPOSTING
TECHNOLOGIESTECHNOLOGIES

15. Backyard Composting
Potential diversion – 400 – 800
lbs/year/household
Suitable materials
Yard trimmings (leaves, grass, shrubs)
Food wastes (produce, coffee grounds, eggshells)
Newspaper
Unsuitable materials
Pet wastes
Animal remains (meat, fish, bones, grease, whole
eggs, dairy products)
Charcoal ashes
Invasive weeds and plants (kudzu, ivy,
Bermudagrass)

16. Types of BYC SystemsTypes of BYC Systems

17. Types of BYC SystemsTypes of BYC Systems

18. Backyard Composting – Easy To Do!
Locate in flat
area, shielded
from sun & wind
Add materials in
layers
(browns/greens)
Turn pile after 1
st

week, then 2-3
times over next
two months

19. Backyard Composting, cont…Backyard Composting, cont…
Can add fresh wastes when
turning, but better to start
new pile
Compost will be ready to
use in
4 – 6 months for piles
started in Spring
6 – 8 months for piles
started in Fall

20. Vermicomposting Home WastesVermicomposting Home Wastes
Vermicompost = worm castings + bedding
Nutrient Value - 6600 ppm organic nitrogen,
1300 ppm phosphorus & 1,000 ppm
potassium
What to feed worms –
Vegetable scraps, breads and grains
Fruit rinds and peels
Tea bags, coffee grounds, coffee filters, etc.
What not to feed worms –
Meat, fish, cheese or butter
Greasy, oily foods
Animal wastes

22. Commercial Composting
Larger-scale commercial and municipal
facilities
Feedstocks: manures, agricultural wastes (I.e.
cotton gin trash), industrial and municipal
wastewater treatment sludges, food wastes
Technologies used:
Windrows
Aerated Compost Bins
Aerated Static Pile
In-Vessel Systems
Produced compost sold for $18 - $20/yd
3

23. Windrow Composting
Materials mixed and formed into windrows
Windrows 7’ –8’ wide, 5’ – 6’ tall, varying lengths
Compost turned and mixed periodically
Aeration by natural/passive air movement
Composting time : 3 – 6 months

24. Windrow Composting, cont.
Equipment Needed
Grinder/Shredder
Tractor/FEL
Windrow Turner
tractor-pulled
self-propelled
Screener
One Acre Can Handle
4,000 - 7,000 CY
Compost Mix

25. Aerated Compost Bins

26. Aerated Compost Bins
Aeration through porous floor plates
Composting time : 2 - 3 weeks
Curing time : 2 months
Durable materials of construction
Equipment needed : front end loader
Vector/vermin control needed with food
wastes
Capacities : 3 - 4 days food waste + bulking
agent per bin

27. Aerated Static Pile Composting
 Mixed materials built on bed with aeration pipes
embedded
 Aeration by mechanical blowers
 Composting for 21 days, followed by curing for 30 days
 Often used in biosolids (sludge) composting

28. Aerated Static Pile
Better suited to larger volumes (landscape
debris, sludges)
Shorter processing time than with windrows
May not be suited to wastes that need mixing
during composting, like food wastes
Difficult to adjust moisture content during
composting if needed
Odor control difficult with positive aeration
Less land area than windrows, still labor
intensive

29. In-Vessel Composting
More mechanically complex
More expensive
Smaller footprint (area)
Relatively high operations & maintenance costs

30. In-Vessel

32. Overview Of Citizen’ Initiatives For Waste Collection
And Composting In India

33. Benefits of
Compost Utilization

34. Compost Benefits
Physical Benefits
Improved soil structure, reduced density, increased
permeability (less erosion potential)
Resists compaction, increased water holding
capacity
Chemical Benefits
Modifies and stabilizes pH
Increases cation exchange capacity (enables soils to
retain nutrients longer, reduces nutrient leaching)
Biological Benefits
Provides soil biota – healthier soils
Suppresses plant diseases

35. More Compost Benefits
Binds heavy metals and other contaminants,
reducing leachability and bioabsorption
Degrades petroleum contaminants in soils
Enhances wetlands restoration by simulating
the characteristics of wetland soils
Coarser composts used as mulch provide
erosion control
Can provide filtration and contaminant
removal of stormwater pollutants
Biofiltration of VOC’s in exhaust gases

36. Typical Compost Characteristics
Parameter Typical Range Importance
pH 5.0 –8.5 Optimum plant health
Soluble Salts 1 – 10 dS
(umhos/cm)
Phytotoxicity
Nutrients N (0.5-2.5%), P (0.2-
2.0%), K (0.3-1.5%)
Plant Vitality
Need for fertilizers
Water Holdng
Capacity
75 - 200% dry weight
basis
Irrigation requirements
Bulk Density 700 - 1200 lbs/yd
3
Handling/Transportation
Moisture
Content
30 – 60% Handling/Transportation
Organic Matter 30 –70% Application Rates
Particle Size < 1” screen size Porosity
Stability Stable – Highly
Stable
Phytotoxicity

37. Summary
Composting is an effective way to manage
organic wastes
Composting promotes environmental
sustainability by converting a waste to a value-
added product that improves our environment
Composting can be done at home, at school or
at work, and by commercial and municipal
entities
Composting is a mix of the art of the gardener,
the science of horticulture, and the discipline of
waste engineering…COMPOST HAPPENS!

38. Why Should You Compost????
BECAUSE IT’S ALL ABOUT RESOURCE
CONSERVATION AND WATER QUALITY!