This document discusses composting methods and their advantages. It describes the composting process and what materials can be composted. Traditional composting methods are simple but require turning the materials regularly over several months. Machines provide automated composting in less time with less labor but have higher costs. Issues like rodents, measuring food waste, and partnerships need consideration for a successful campus composting program.

1. Sustainable CUNY
 Composting:
 Process
 Advantages
 Methods
 Issues

2. 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)

3. 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)
3

4. 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

5. 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
5

6. 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

7. 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)

8. 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
8

9. 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
9

10. 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)
10