|
Unless
facility operators fully understand the manufacturing
process and its inherent difficulties, failure is indeed
an option.
By
Ron Alexander
Commercial-scale
composting in the United Kingdom has grown significantly
over the past several years, and will continue to expand
into the foreseeable future. As the industry has grown,
both landfill operators and waste managers have begun
to study the science of composting, and both now see
it as a recycling and manufacturing process. Today,
composting is well understood as a manufacturing process,
and clever composters can manipulate the process to
manufacture products that best meet the requirements
of their specific end users. However, even as the worldwide
composting industry has seen its successes grow significantly,
so too have its failures.
For the United Kingdom, organics have become priority
materials to recycle because they are easy to target
within the wastestream and can make a large impact quickly
in meeting overall recycling targets. Also, some infrastructural
requirements for the collection and management of organics
already exist. However, different barriers and opportunities
exist in organics management compared with more traditional
recyclables. Organic materials differ from traditional
recyclables most in that they are putrescible in nature.
Of course, there are significant drivers to enhance
the collection and management of organic materials.
These drivers include the European Union (EU) Landfill
Directive, Waste Strategy 2000, and Local Authority
Recycling Targets.
In the Merseyside region of the United Kingdom alone,
EU Landfill Directive targets require 314,000 tons of
organics to be managed by 2020, and Waste Strategy 2000
targets require 104,000 tons of recyclables to be generated
by 20032004. Organic feedstocks that will be targeted
in the short term primarily include garden waste and,
later, kitchen waste as well as non-recyclable wood,
paper, and cardboard. It is likely that much of these
organics will be collected in source-separated fashion,
but mixed-solid-waste composting is also an option that
some local authorities may consider.
A variety of composting methods may be used in organics
management based on the specific feedstock to be composted.
Where outdoor windrow systems are less complicated and
engineered and may be appropriate for feedstocks such
as garden waste, in-vessel systems (which are typically
patented) are often used for highly putrescible feedstocks
and those that are more difficult to manage (e.g., kitchen
waste, biosolids, MSW). As "big technology options"
become more financially viable for use in the United
Kingdom, the opportunity for great successes, as well
as great failures, exists. Failures are likely because
these "black box" technologies often are seen as panaceas
by non-technical individuals involved in the decision-making
process. As a result, to help Britain develop a healthy
composting industry and avoid industry failures, a study
was completed within the US composting industry to evaluate
why specific composting (and other waste management)
facilities failed. In it, 21 North American facilities
were identified, with the focus on biosolids and MSW
composting facilities. One digester and a materials
recycling facility (MRF) also were evaluated. Of the
19 composting facilities, seven are still in operation,
and 12 of the "failed facilities" alone represent losses
of $423 million to $500 million.
The UK composting industry has specific challenges and
issues that are unique to it, and they must be addressed
for it to grow to the extent necessary. To its benefit,
the organics management industry has strong political
drivers forcing its positive movement and therefore
creating great interest, as well as investment, in the
industry. However, based on UK regulation and EU legislation,
a great deal of work must be done to expand the industry
in a limited amount of time. Unfortunately, this creates
an atmosphere where significant mistakes can occur.
The UK also must deal with such issues as space restrictions,
uncertainty in future regulation and legislation, underdeveloped
compost markets, consultancy and operational inexperience,
and a complicated waste management infrastructure.
What Goes
Wrong
To assist the industry in avoiding errors common in composting-facility
development, here are some common mistakes found to
contribute to facility failures.
Facility
Design
The mistakes made in the overall design of composting
are numerous. Major factors include a lack of overall
experience and an understanding of the composting process,
as well as inexperience in the management of organic
materials. These mistakes have been caused by consultancy
companies and their clients (local authorities and private
companies) by trying to meet unrealistic economic parameters,
by usurping the formal review process, and, at times,
by getting too involved in the overall design without
possessing proper and related experience. Facility design
must take into consideration the biological nature of
the process, odor management, and product-quality issues.
Technology
Selection/Equipment
Consultants,
their clients, and politicians have made mistakes by
becoming enamored of a specific composting technology
to the exclusion of others. At times, the favored systems
have simply not worked, while in other cases the systems
were not appropriate for the location or feedstocks.
It is vital to obtain assistance from companies that
possess experience in the composting process and equipment
selection, as well as the varieties of technologies
and equipment available, before a preferred technology
is chosen and a tender is designed around it.
Odor/Odor
Control Systems
Probably the greatest cause of facility "shutdowns"
in the United States—and probably the world—is
odors. Although odors are always generated during the
commercial composting process, the volume of the odorous
air stream, as well as the types of odorous compounds,
can greatly affect the severity of the potential odor
problem off-site. Odor systems are often underdesigned,
unable to handle the quantity of air necessary for proper
odor control, ineffective on the specific odorous compounds,
or not included in the original facility design at all.
The science of odor control and odor monitoring is very
complex, but the reaction of the general public is not.
Odor generation and management must be considered in
the design phase of facility development, but proper
operation of the facility is often the key to reducing
odor generation and movement off-site.
Siting
The
location of a composting facility often goes hand-in-hand
with odor issues. Siting a facility too close to neighbors
is a classic mistake of the composting industry. Even
"in-vessel" systems are affected by siting issues related
to odor generation. The logistics of a composting operation,
which relate back to traffic or vehicles entering and
leaving the facility, should never be disregarded. Truck
traffic has caused problems with neighbors of composting
facilities and has caused stress on infrastructure.
Product
Quality/Marketing
Producing
a compost product that meets the quality requirements
of the customer dramatically affects its marketability.
However, aside from product-quality issues, history
has also shown that a lack of market-development activity
and underestimating the requirements necessary to develop
a successful marketing program also have caused marketing
failures.
One way to avoid such failures is to determine the realistic
quality of product you expect to produce, and then do
market research to determine if markets exist for it.
Market research should be a significant part of your
facility design and evaluation process. Understanding
the needs of the market, as well as the investment necessary
to develop a revenue-generating marketing program, is
often overlooked. Poor marketing leads to large piles
of compost being built throughout the composting facility.
This may lead to odor generation, logistical problems
at the composting site, public relations difficulties,
etc.
Misunderstanding
Waste Characteristics and Properly Controlling Facility
Inputs
Large-scale
composting facilities, especially MSW composting facilities,
should never be developed without completing a proper
waste characterization. Using national or regional characterization
figures, which did not represent actual waste characteristics,
has caused great difficulty at several composting facilities.
This is because misunderstanding the waste characteristics
can greatly affect the operational costs and input capacity
of a facility.
Facilities composting biosolids have been developed with
the understanding that garden waste from local municipalities
would be used as the bulking agent, only to find out
that the majority of the waste was grass and not "woody"
(carbon-rich). As a result, the facilities had to purchase
woodchips for use as a bulking agent, which significantly
increased their operational costs.
MSW composting facilities have been designed with a belief
that food-based materials and packaging would be the
primary inputs, only to find that great volumes of non-recyclable
paper and card were a majority of their feedstock. Other
facilities have been designed and built assuming that
the proper volume of feedstocks was available to make
the facility financially viable, only to be proven incorrect.
Also, assumptions should never be made when it comes
to the ability to control the flow of waste materials
entering the facility. Proper volumes must be guaranteed
and contracted for before the facility is developed.
Politics
Several
composting facilities were doomed from the start because
of poor political decisions in the design of the composting
facility. Examples exist where local politicians have
been invited on junkets to evaluate composting facilities
without involving proper technical representation to
assist them. Poor systems choices have been made as
well because powerful members of the selection committee
have been enamored by specific composting systems, even
though those systems were not the best for their particular
situation.
Politics dealing with local residents and regulatory
bodies also have caused the operation of many facilities
to be altered or snuffed out completely. The lesson
is that technical decisions need to be made by technical
individuals who have practical experience.
Financial
Failures
have also occurred because composting facilities were
undercapitalized from the beginning and were unable
to properly operate without compromising the long-term
integrity of the program. Undercapitalized facilities
have been forced to ramp up too quickly, trying to manage
larger volumes of incoming waste than they were able
to during the startup phase (so they could receive additional
gate fees). This caused odor problems, forcing improper
performance testing of equipment, and the production
of poor-quality compost.
In other cases, little money was set aside for contingencies
or upgrades to the system, forcing the facility to limp
along until revenue could be generated to make repairs
or upgrade the system. Also, in-depth evaluations of
the cost to build and operate the facility have been
improperly completed during the design of some facilities,
leading to a higher cost per ton to manage the materials
than expected (or promised by the technology provider).
We have seen successes and failures, and what we have
learned is that most of the latter can be avoided. One
of the best ways to avoid failures in the development
of large-scale composting facilities is simply to understand
the realities of composting. Some of these realities
are:
- Composting
is an excellent waste management option, but it is
not a perfect option for every organics management
application.
- Composting
is both an engineering and biological process.
- No
composting facility is odor-free.
- Even
successful composting facilities have problems from
time to time.
- Most composting
facilities create "reject" material (product that
has to be landfilled). MSW composting facilities often
have a 35%-45% reject rate.
- Operational
challenges increase exponentially with facility size.
- Developing
markets for compost products takes time and investment
(no composting facility should be developed without
an understanding of where the compost will be used).
- If
it sounds too good, it usually is.
To improve your chances of success, learn from past successes
and failures. We must allow past experiences in compost
facility design and operation to shape the design and
operation of future facilities. The keys to shaping
your facility are:
- Understand
the composting process.
- Seek out
assistance with the facility-development process.
- Select
the proper composting technology and consultancy assistance.
- Understand
your markets.
- Allow
for proper planning and technical review process.
- Start
the planning/design process early (don't let a short
time frame cause bad decision-making).
- Never
be a guinea pig—don't be the first one to develop
a composting facility based on a new or unproven technology.
Remember that bigger and/or higher technology solutions
are not always the best choice.
Acknowledgements
This
paper is based on research commissioned and funded by
the Clean Merseyside Centre. Special thanks to Sig Scheurle,
Minnesota Office of Environmental Assistance, for information
provided on the Minnesota experience.
Guest author Ron Alexander, based in Apex, NC, has
been involved in the composting industry for more than
15 years.
MSW
- September/October 2004
|
