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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