North Carolina Cooperative Extension Service
Information provided by
North Carolina
Cooperative Extension Service
Rhonda Sherman,
Waste Management Extension Specialist
Biological &
Agricultural Engineering
Box 7625, Raleigh,
NC 27695-7625
Phone: (919)
515-6770 Fax: (919)
515-6772
e-mail:
sherman@eos.ncsu.edu
URL:
http://www.bae.ncsu.edu/people/faculty/sherman
BAE-W5 - April 1997
(revised 6/97)
Grace McKellar Centre,
Geelong, Victoria, Australia
About 13 cubic yards per week of
kitchen scraps, shredded paper, and garden trimmings are vermicomposted in
open-air beds at this hospital. Zeolite and soil are mixed in for pH and odor
control, and weeper hoses in the beds provide moisture. Current landfill
tipping fee cost savings are $4,000 per year (local tipping fees are $6/cy).
Projected savings are $14,000 per year when capacity is reached at three times
the current amount being processed.
Green Cross Society of
Bombay, India
To curb the vermin population in
Bombay, this non-profit organization has set up several projects to convert
organics into vermicompost. For example, a smaller-scale operation
vermicomposts 4 tons of slaughter house waste per day. A larger operation,
which vermicomposts 20 tons of vegetable waste per day, has been set up in
Kalyan, north of Bombay, in collaboration with the Bombay Municipal
Corporation.
Hobart City Council,
Tasmania, Australia
Worms digest about 66 cubic yards
of municipal biosolids per week, along with green mulch. Zeolite mixed in with
the feedstocks helps balance the pH and absorb ammonia and odors. About
two-thirds of this volume becomes vermicompost, which is sold to the public on
site. They plan to expand the operation to process 330 cubic yards per week.
The City of Hobart is currently saving $56,000 per year from avoided landfill
tipping fees, and they are receiving an equal amount of revenue from their
sales of vermicompost.
Indian Aluminum Co. Ltd,
Belgaum, India
Since July 1995, vermicomposting
has been used to process garbage and sewage from 500 homes. Compostable garbage
is processed in seven concrete vermicomposting bins (one for each day of the
week) measuring 7 x 20 meters. Sewage is fed to a 200 square meter
"vermifilter"--a biofilter with a 30 cubic meter deep bed of
vermicompost which contains earthworms and a root zone of selected plants. The
vermifilter can process up to 100 cubic meters of sewage per day, and the
purified water is used to irrigate gardens. This low-labor system needs little
operation and maintenance. This is one of six large-scale vermicomposting
projects developed by Bhawalkar Earthworm Research Institute that have
motivated about 5,000 farmers in 16 Indian states to vermicompost their organic
materials.
National Institute of
Environmental Health Sciences, Research Triangle Park, North Carolina, United
States
In late 1996, NIEHS purchased two
heated worm composting units, called Worm Wigwams, and 10 pounds of worms.
Shredded confidential office paper and finely shredded wood rejected for animal
bedding for NIEHS's labs is used for bedding. Staff volunteers take turns
bringing 10 to 20 pounds of food scraps each day from the cafeteria to the worm
bins, located outdoors, near the facility. Employees use the worm castings as a
soil conditioner for their plants.
Newcastle City Council, New
South Wales, Australia
This city is saving $32,000 to
$37,000 annually on avoided landfill tipping fees by vermicomposting 33 cubic
yards per week of biosolids and vegetable scraps in a 1:1 ratio. Potential
savings are estimated to be $129,000 to $150,000 per year when they reach their
goal of processing 130 cubic yards per week. The resulting vermicompost (40
percent of the input) is harvested weekly, bagged and sold to major
supermarkets in Melbourne and Sydney for approximately $67,000 per
year.
Oregon Soil Corporation,
Beaverton, Oregon, United States
Since 1991, an automated
vermicomposting system has been used to process 12 to 14 tons per day of yard
trimmings and pre-consumer food scraps collected from supermarkets at a charge
of $65 per ton (landfill tipping fees are $80 per ton). The organic materials
are ground up and then mechanically applied in three-inch layers by a
retrofitted manure spreader on a gantry which travels over the bed of a 120 x 8
x 2.5 foot (960 square feet) "continuous flow reactor." Vermicompost,
which is produced in as little as 30 days and sold for $25 a ton, is scraped
off the two-inch mesh screen under the raised bed daily, half-an-inch at a
time. About 3,000 tons per year of the vermicompost is sold as "Oregon
Soil All-Purpose Planting Mix" in one-cubic foot bags in a chain store in
four or five states. This pilot-scale reactor cost about $40,000 to construct;
another $50,000 was spent to build a greenhouse-like structure and buy a
leachate tank and other equipment.
Pacific Southwest Farms,
Ontario, California, United States
One of the largest vermicomposting
operations in the United States, PSF has 360 windrows measuring 8 feet by 100
feet on their 54-acre site. More than 100 tons of worms are fed four tons per
row per week (100 tons per day) of municipal solid "green" waste
brought from materials recovery facilities (MRFs). Their feedstocks include
manure, tea, untreated wood, food-contaminated paper, and natural-fiber
products. About 45 percent of their income is from sales of castings
agricultural users; the rest is from tipping fees. Plans for expansion include
a 120-acre site in Bakersfield and two other 50-acre sites.
Resource Conversion
Corporation/Canyon Recycling, San Diego, California, U.S.
This company vermicomposts 35,000
tons of organic materials each year, including yard trimmings, manure from the
San Diego Zoo and Wild Animal Park, and construction and demolition debris.
Their vermicompost, which is marketed under the trade name VermiGro, sells for
$35 per cubic yard (regular compost sells for $5 per cubic
yard).
Rideau Regional Hospital,
Perth, Ontario, Canada
Officials at this 725-bed hospital,
with 1000 staff members, decided to vermicompost the 825 pounds of wet organics
produced each day. A pulper reduces the amount of food scraps by half, by
removing the water. They constructed 20 bins, each 3' x 4' x 30" high,
filled them with shredded newspaper and soil bedding, and added a total of 100
pounds of redworms. The beds are located in a greenhouse, which has to contend
with temperatures ranging from 86F degrees to 22F below.
San Quentin Prison,
California
In 1994, San Quentin Prison added
vermicomposting to its Recycling and Salvage Program (RASP). Starting with two
10-foot by 3-foot worm bins, within three years they expanded to 15 bins, all
constructed from salvaged scrap wood from the prison recycling center. In
1996-97, worms consumed 400 pounds of food scraps weekly, producting 11,000
pounds of castings and an extra 17,000 worms. Food scraps from the prison ranch
kitchen are collected and buried daily in the worm bins, and paper collected
from all offices at the prison is shredded and added to the bins as bedding.
One or two inmates are assigned to the vermicomposting center each year to
maintain and harvest the bins. Every four to six months, the bins are harvested
for castings and excess worms. Although most of the castings are used by the
prison landscaper in San Quentin's garden areas and flower beds, leftover
castings are placed into buckets recovered from the prison's main mess hall and
sold to prison staff to use on their house plants and gardens. Prison staff may
also purchase harvested worms to use as fishing bait or to start their own worm
bins. Prison officials are pleased with the success of the vermicomposting
program, as it not only diverts food scraps from the landfill and provides the
prison with a valuable soil amendment, it produces an income that supports
their recycling program.
Seattle Kingdome Stadium,
Seattle, Washington, United States
In 1994, the stadium's successful
recycling program was expanded to include vermicomposting. About 18,000 worms
in 12 containers eat 50 pounds of food scraps (30 percent of the stadium's
total food waste) per week. The worms live in a bedding of leaves and shredded
newspaper, and eat mostly pre-consumer salad scraps. They report no problems
with odors or pests, and the worm castings are used on the Kingdome's flower
beds.
Sovadec, La Voulte,
France
Since 1991, this company has been
operating on Rhone River in the south of France, vermicomposting 20 tons of
mixed household waste per day. A thermal process opens plastic bags filled with
refuse, and the contents are separated by automated equipment and hand sorters.
Textiles, paper, cardboard, plastics, glass and metals are recycled, and the
remaining materials are composted aerobically to eliminate pathogens, weeds and
other harmful organisms. Next, the organic materials are processed in
'lombricubateurs' (earthworm tanks) which each have a 15 ton per day capacity,
using 1,000 to 2,000 million redworms of the variety eisenia andrei. The
resulting vermicompost meets most stringent European standards; non-organic
material is less than 50mm in size.
Vermiculture Production
Center, Pinar del Rio Province, Cuba
The largest of Cuba's 170
vermicomposting centers, this facility uses cow manure as its primary
feedstock, in addition to pig and sheep manure, sugar cane pulp, coffee pulp,
and other crop residues. The feedstock is thermophilically composted in
twice-weekly turned windrows for 15 to 30 days before being fed to the worms.
Vermicomposting takes place in windrows covering four
hectares of orchard land. Thin layers
of feedstock are spread by a tractor-drawn manure spreader. When the windrows
reach a height of 65cm, worms are drawn to the surface with a layer of fresh
feed, then five to seven days later a front-end loader is used to skim the top
10cm off of the windrow, removing 80 percent of the worms. The worm harvest can
be brought to 90 to 92 percent with a second feeding and loader pass. A
mechanical harvester is used to separate the worms from their castings.
Castings are used to replace manure as a fertilizer for tobacco; they are also
applied to corn, tomatoes, garlic, onions, and coffee bush nursery
stock.
Vermicycle Organics, Inc.,
Charlotte, North Carolina, United States
More than five tons per week of
swine manure solids is being vermicomposted at a farm in
Wilson, North
Carolina. Manure that has passed through an automated solids separator between
the swine house and lagoon is placed on a 15 x 15 foot concrete pad. A
front-end loader transports the manure to a 30 x 200 foot greenhouse, and a
spreader delivers manure to 2 x 190 foot wooden worm beds which each hold
thousands of pounds of redworms. Temperature and moisture are controlled
through the use of greenhouse curtains, shade cloth, fans, and an automatic
mister. Castings are lifted and conveyed from the beds every other month by a
retrofitted machine, and a harvester separates worms and eggs from the
castings. Castings are sold in 2-, 10- and 25-pound bags marked
"Vermicycle: Nature's Ultimate Plant Food." Less than eight weekly
person-hours are required to manage the operation.