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check out this informational pdf about composting!
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Sustainable CUNY
Composting:
Process
Advantages
Methods
Issues
Process
What can be composted?
food waste food scraps, coffee grounds, tea leaves, eggs shells, shredded papers,
dairy, bread, vacuum cleaner contents, canned fruit & vegetable liquids…
meat / fats not encouraged
yard waste grass clippings / leaves / bark / dead wood / prunnings…
certain compostable plastics
How does it work?
bacteria & other micro-organisms break down waste
two outcomes – mulch or humus
oxygen vital to the process (aerobic decomposition)
no oxygen = anaerobic decomposition = methane (a GHG)
Advantages
GHG reduction:
1 ton composted waste = approx 1 metric ton reduction in GHG
waste volumes a factor in your campus’ emissions calculation
Reduced waste haulage costs:
lower volumes = lower costs
waste haulage arrangements & costs vary across CUNY
Usable end-product:
mulch or humus can be reused on campus grounds
can be donated / sold locally (parks, community gardens…)
Educational value:
inclusive & participatory (esp. traditional methods)
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Methods
Pulping:
not strictly composting – simply reduces volume of waste
output can be composted or discarded
machine = requires water & electricity to operate
Machines that do the work:
minimize need for hands-on effort
volume of waste key factor in adopting tech solution outlay costs absorbed by reduced haulage costs?
sufficiently large / steady stream of waste produced to feed machine?
a power source & water source usually necessary
space requirements vary depending on the technology
initial training necessary (use & maintenance)4
Pulpers
Characteristics:
can reduce food (& yard) waste volume by 80%
can reduce weight by 50%
can convert up to 1,000lbs of waste to pulp in 1 hour
increases the capacity of your composter
increases the quality of your compost
available in sizes from 500 lbs/hr
$15,000 - $50,000
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The Rocket
Characteristics:
turns food & yard waste into compost in 14 days
successfully used by many British businesses and universities
catching on in USA (St. Johns in NYC)
can be operated in a limited amount of space Smallest machine is 2.0m long, 0.7m wide, 1.4m high
Largest machine is 6.0m long, 1.0m wide and 1.8m high
available in 4 sizes
can process 50 to 7000 liters of organic wastes per week
little manual effort required
no odor, no rodents and no insects
$18,000 - $40,000
BioHiTech
Characteristics:
turns food waste into waste water which is flushed into the sewage system
used in restaurants, hotels, supermarkets, universities
available in 3 sizes (400lbs – 1,200lbs of waste)
largest machine can process 1 ton of waste per day
minimal operational training needed – machine runs itself
no permitting or code issues
no odor or rodents
placement assessed as part of service (waste area / kitchen)
can buy or rent $23,000 - $40,000 (excl. service agreement)
$1,000 per month rent incl. service agreement (minimum 3 year lease)
Methods
Traditional Methods:
can be done on any scale
use containers made from numerous types of material wood, chicken wire, pallets, plastic bins, old street bins…
can mix food & yard waste
layering of waste types & aeration important to process
requires turning (approx. once per week)
speed of process varies depending on seasonal temperature 3 weeks in summer under ideal conditions
several months in winter
most engaging / participatory option students & staff can add their food waste or get involved in the process
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Issues
Rodents:
genuine issue
machines claim to reduce this problem
Measuring food waste:
critical in determining value & method of composting
5-day week / reduced activity in summer will impact waste quantities
Cooperation of dining service vendor:
kitchen-side food waste easiest place to start
education / cooperation of key staff necessary
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Issues
Composting partnerships:
parks, community & botanical gardens accept donations
DSNY runs the ‘NYC Compost Project’ information / resources / training
http://www.nyccompost.org/contact.html
some companies in NYC take organic waste for composting http://www.actioncarting.com ($0.06 per lb)
http://www.filcocarting.com ($15 per 23 gallon container)
Including students & staff:
a topic which can engage & educate (esp. traditional forms)
later phase in program = collection of their food waste (cafeterias / classrooms / office areas)
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