the '90s, the necessity of choosing from a mix of collection,
processing, and disposal technologies adaptable to changing demands
complicates meeting the challenge of integrated waste management
demands, including the need to conserve energy and natural resources
in an increasingly urbanized world. In the United States, the
rapid proliferation of source separation of municipal refuse helps
to simplify solid waste systems. Recent trends move toward the
concept of integrated waste management involving source reduction,
recycling, transformation and disposal as a means to provide sound
system control and environmental protection. With more personalized
and convenience-oriented commodities, conversion of waste to industrial
feedstocks presents one way to reduce disposal masses as well
as provide for societal-material needs.
The economic and
political concept of supply and demand leads to a social and technical
transition toward integrated waste management systems. With acute
shortages in land and raw materials, Europeans, out of necessity,
developed considerable experience in mechanical recovery systems.
Municipalities and private waste management companies want to
know if this experience in operating municipal refuse recovery
plants applies to American systems of source separation and separate
collection. We visited European plants with different mechanical
processing systems and end-products and also reviewed the accompanying
solid waste systems to help answer that question.
to the recovery systems built by Triga in Neuchatel, Switzerland
(processing for materials separation and incineration); Daneco in
Tolmezzo and Udine, Italy (processing for materials separation and
composting); and Sorrain in Perugia, Italy (processing for materials
separation and composting). At each of the plants, the companies
modified the present day operating systems over the mature-plant
operating life to meet the standard of changing market needs and
increasingly-strict environmental statutes.
all cases, the operations
adjustments in the
move the organic materials collected in Perugia, Italy to a discharge
belt over a 28-day cycle.
in the three waste management systems existed. In all cases, they
made adjustments in the collection systems to accommodate source
separation, predominantly glass and newspaper, and prepared end-product
materials for local market demand. Several communities shared the
management of the systems in shared partnerships. And in each case,
operating permits and environmental regulations necessitated development
of alternative separation systems.
goal of each plant was to reduce the amount of residual material
landfilled and to minimize costs within environmental limits.
determined the waste stream and subsequent recovery technology,
however different. Neuchatel built its waste-to-energy system prior
to initiating materials separation. It added the processing technology
to reduce costs and provide a cleaner and more consistent fuel.
The system in Tolmezzo served as a prototype for Udine and by design
provides soils amendment for surrounding agricultural operations.
Volume reduction at the landfill and production of a quality agricultural
product drive the separation system. In Perugia the operation of
the collection and disposal system demonstrates technically improved
mechanical equipment to provide better quality resources, as well
as extend the life of the existing landfill. In all cases they view
source separation as a technically desirable method to enhance materials-market
quality and improve environmental compliance.
of Zurich, west of Bern and just east of France lies Lake Neuchatel.
Along the shore of Lake Neuchatel live 120,000 people in 48 townships.
The town of Neuchatel is clean and well kept. The convenient location
of litter collection container mitigates some of the impacts of
tourism economy. Igloos accepted color-sorted glass and we saw evidence
of scheduled separate collection for newsprint throughout the community.
Rear-loading trucks handled collection efficiently and separate
routes allowed for the capture of commercial waste separately from
mixed residential waste.
In 1968, 48 communities joined to form a limited Swiss operation
named SALOD Co. The company financed, constructed and continues
to operated a waste-to-energy incinerator with a front-end separation
system. The plant began operation in 1971 and continuously updated
its facility to comply with environmental requirements. In 1989
it added front-end processing to contend with increasing waste flows
and to decrease environmental emissions. This resulted in improved
quality and an increased variety of marketable resources. The processing
phase of the overall management system captures the fiber-rich commercial
waste stream by means of facilities designed by Triga.
conveyor transports commercial waste to a trommel for separation
of fiber and wood from organic, metal and glass. Magnets remove
any ferrous material. Workers hand sort the resulting non-fiber
fractions from other metals.
hand sort the fiber fraction line, primarily to recover corrugated
cardboard. The facility bales the resulting fiber fractions for
uses as a high energy fuel additive in the incinerator.
transport the metal to the town of Lausanne for sale as scrap. Residual
from the non-fiber fraction travels 20 miles for landfilling. Residential
non-source separated materials move directly to the incinerator
for generating steam and electricity as products of volume reduction.
Ash remains on-site.
shareholders (elected officials from member communities) operate
the plant and currently plan to expand material sorting and to improve
air emissions controls. These plans aid in developing recovery programs
for aluminum, other metals, and miscellaneous materials such as
batteries and florescent lights. Workers dump and aggregate drop-off
bins containing separated clear and colored glass at the plant for
rail haul to markets. The facility also processes newspaper and
cardboard. Landfill cost increases as well as the limited capacity
of the incinerator helped to increase interest in mechanical separation
quality and source separation systems.
in the Neuchatel system improved the quality of the refuse derived
fuel used by the mass burn system and by increased supplies of recycled
of the combustible/fiber supply provides the community with a more
reliable heat source in the cold, winter months. The facility saves
some mixed paper separated in the summer for use as auxiliary fuel
in peak winter demand periods.
Italy lies in the Venetian are region (within an hour's drive from
Austria and twenty minutes from Yugoslavia) where agriculture and
light manufacturing make up the main industries. Near Udine is the
small town of Tolmezzo nestled in the mountainous Carnia Region.
Operated under contract with the Comunita Montardella Carnin and
48 communities in neighboring areas totaling 85,000 inhabitants,
the Tolmezzo processing facility uses magnets and a trommel/cyclone
combination to clean rural-collected solid waste for compost and
trommel set at a 6 percent angle separates the plastic from shredded
paper at the Perugia Italy facility. The plastic, which appears
to consist of approximately 90 percent film, then goes to a washer,
dryer, extruder, die cut and pellitizer line currently under construction.
Operators in the control room of the Perugia, Italy complex
oversee the functions of the 400 tons per-day facility
regional government monitors the tests on the quality of the
and its effect on agricultural crops.
FACILITY. A Daneco-designed gasifier, designed to convert the
RDF to gas to be used to generate electricity, is under construction
in Tolmezzo. The plant serves as the model for a significantly larger
facility designed by Daneco (an engineering design firm) and currently
under construction in Udine. When completed, Udine expects the facility
to serve its urban population of more than 100,000.
to refine its technology for application in the Udine facility.
The compost from Tolmezzo is currently being tested at an agricultural
research farm. The regional government monitors the tests on the
quality of the compost and its effects on agricultural crops for
crop quality and solid waste-related impacts. Concerns with lead
and other trace metals in the compost provides impetus to include
ferrous recovery in the mechanical processing. Other aesthetic concerns
necessitated addressing glass and plastic removal techniques.
system accepts mixed residual and commercial waste in a recovery
pit. A crane delivers the waste to a hopper-conveyor system that
includes a bag breaker and a magnet for ferrous removal. The material
then enters a rotating cylinder for a half-day to allow microbial
activity to begin. Conveyers next move the material to a trommel
and cyclone processing system to remove other heavy and oversized
materials. This achieves a high removal of nonferrous metal, inerts
and glass. The system takes the remaining, predominantly organic
material to a curing area for air injecting and conversion of the
material into compost. A vibrating screen removes any large non-composted
items and completes the final refining of the compost.
for groundwater protection from landfilling resulted in a Daneco
contract with the city of Udine for an expanded and updated compost
and RDF production system. Local efforts in Udine increased the
feedstock cleanliness with drop-off collection containers to recover
paper and sorted glass. Officials expect the upscale facility for
Udine to cost about $18 million. It's location near the city's sewage
treatment plant provides the potential currently under evaluation
of adding treated sludge for compost process enhancement.
system's flexibility allows it to enjoy the benefits of source separation.
The extraction of metal, glass, and plastic increase the quality
of the organic materials, and city officials expect tot develop
markets for the compost. RDF remains another market in a development
stage. Gasifying the refuse derived fuel provides additional resource
recovery potential through generating electricity. The residual
material destined for a landfill consists of a stable mix of dirt,
inerts, glass, mixed metals and small amounts of organics.
CONTROLS. The town of Perugia dates from ancient Rome and contains
numerous secular and ecclesiastical structures from the Middle Ages.
Today, in addition to being an industrial and commercial center,
it serves as the capital of Umbria and boasts a thriving, international
university. The facility in Perugia demonstrates the latest Sorrain
waste processing technology and operates under strict environmental
controls. Although no burning takes place in uses scrubbers to reduce
air emissions. It treats and recycles all wastewater. The basically
mechanical resource recovery system uses no hand sorting. Italian
law forbids facilities to hand sort mixed wastes.
renegotiated its contract with the town of Perugia in 1984 to provide
collection , street sweeping, mechanical waste processing and disposal.
The city and company work in a partnership where they share the
profit (55 percent goes to the company and 45 percent to the community).
The system handles 400 tons per day and charges the residents by
land-size fees. The average home of about 80 to 100 square meters
pays about t $100 per year for refuse management. Perugia initiated
and then later discontinued a source separation collection program
due to continually decreasing participation. The University of Perugia
tests compost from the Sorrain plant for environmental parameters.
the Neuchatel, Switzerland operation, refuse derived fuel helped
provide steam for heat in the winter months.
igloos serve as collection points as part of Udine, Italy's recycling
The plant in Perugia
utilizes a mechanical system of classification and "cold-working"
(non-combustion separation of paper from cans). Sorrain designed
it to recover the following materials:
- Organic, 45 percent;
- Inerts (glass, etc.),
- Paper, textiles,
cardboard and wood, 20 percent;
- Plastic, 7 percent;
- Ferrous, 3 percent
The system initiates
processing with a pit and crane. A bag-breaker conveys the material
to a trommel that consists of two cylinders rotating in opposite
directions. Magnets remove the ferrous fraction and conveyors
take the metal to a baler.
Air blows the large materials into a cyclone to divide lights from
heavies. The system directs the light material to a differential
shredder which cuts paper but leaves plastic (polyethylene) intact.
A trommel at a 6 percent angle separates the paper from the plastic.
The equipment densifies the paper into RDF pellets for marketing
as a fuel additive for cement plants. The plastic, which appears
90 percent clean film, goes to a newly constructed washer, drier,
extruder, die cut, and pelletizer line.
fraction moves to a composting plant where a trommel is separates
out small non-organic heavies and metals. The organic material is
spread evenly in a large pit where augers remove it over a 28-day
cycle to a discharge belt. The cleaning and screening system uses
two trommels, air classifiers and cyclones and effectively removes
most non-organics. Residual material goes to a landfill at a facility
located adjacent to the composting plant.
these integrated systems in different countries with different currencies
and languages we negotiated planes, trains, taxis, autos, buses
and subways using common symbols with few spoken words as we only
conversed in English. The medium of exchange for service remained
universal: money. Because of universal symbols and technologies
we booked rooms, attended soccer games, recycled certain commodities
and disposed of waste properly with few problems. Udine and Neuchatel
accomplished recycling easier, but each of the three cities operated
efficient street cleaning and litter control systems. The universal
desires for food, shelter, cleanliness, and material conveniences
- basic human needs - know no international boundaries.
|In the cities
in Europe where we traveled, the legislative and educational approaches
to waste reduction just began catching on. Europeans, however, generate
less refuse than Americans. Citizen of Rome, as well as in most
other European cities, generate about two pounds per person per
day, significantly less than the American average of over six pounds.
European refuse arriving at the processing facilities typically
contains higher amounts of organic waste and tends to consist of
significantly less convenience packaging materials than its American
counterpart. The lack of garbage disposals in homes and the existence
of a strong traditional scrap recovery industry accounts for some
of these differences.
CONCERNS. The environmental results of source separation appeared
clear in all visited programs. Each plant manager indicated that
increased source separation improved capacity and product quality,
reduced air, water and residual emissions, and provided additional
revenue to the system. Although each area employed safeguards, they
held common concerns about hazardous wastes and metal emissions.
In the organic fraction, the visibility of small-sized hard plastics
surfaced as a cosmetic problem.
Europe the issue of provided public education for integrated waste
involving waste reduction and source separation raised similar questions
now being considered in the United States. As in the United States
few trained professionals exist in the field. However in the three
geographic areas we visited, many people understood the word "recycle"
or recognized the international recycling symbol. It is apparent
that waste management professionals in Europe recognize that waste
reduction and recycling have ever-increasing public support.
integrated waste management programs as introduced in Oregon, New
Jersey, California, and Rhode Island represent an enhancement to
the mechanical equipment developed and demonstrated in Europe.
Anthony is the principal solid waste program manager for San Diego
County, and James Mang is an environmental engineer.