Courtesy : researchrepository.wvu.edu
Composting case study
The purpose of this study is to evaluate WVU’s current composting efforts and address
the feasibility of a new waste management system. Other land grant universities’ composting
systems will be compared to see which have been most successful, as well as to see which
methods could be applied at WVU. Improving WVU’s composting system will allow us to reap
similar benefits that other LGU’s have seen and create opportunities for teaching, research, and
outreach. It would also teach both students and the community how to be better environmental
stewards by being mindful of our waste. This area is a weak spot in our local food system and
needs to be investigated and improved upon.
Problem Statement
Due to an informally managed compost system at the WVU Animal Sciences Farm, some
raw manure and other waste is running off into the environment as well as being transferred to
the WVU Organic Farm to treat soil in an inopportune form.
Objectives
The objectives of this investigation are to:
● Identify composting efforts at other LGUs
● Evaluate current composting efforts at WVU
● Compare methods of composting to see which would best fit our needs
● Identify any barriers to changing the waste management system
Methods of institutional composting and model land grant universities utilizing these
methods need to be investigated, then suggestions will be made to improve the waste
management at WVU.
REVIEW OF LITERATURE
Closing the Nutrient Gap
When food waste, yard scraps, and animal manure are not diverted back into our food
system it creates a gap in what could otherwise be a continuous nutrient cycle. This is because
each of these wastes contain nutrients that can be introduced back into soil to help grow new
crops. Organic and inorganic matter cycle through this loop in various forms, including: soil,plants, animals, humans and their waste. The balance of these nutrients in the soil, such as
Nitrogen and Phosphorus, is a delicate ratio necessary for plant growth. The wrong ratio will
harm plant growth and when too much is added to soil it will runoff into the surrounding
environment or contaminate groundwater. This runoff can be harmful to the environment and
also means that these nutrients are not being directed back into the agricultural and food systems.
Composting allows for these nutrients to be harnessed and applied back to the soil. However, the
overapplication of compost could also lead to too much organic material accumulating in the
soil.
Composting
The composting process converts organic waste materials into environmentally beneficial
soil amendments, diverts wastes from landfills, and treats these wastes to control pathogens,
whether human, animal, or plant . The science of composting is complex and
includes multiple overlapping process: physical, chemical, and biological. Bacteria are the
powerhouse of a compost pile. They break down plant matter and release carbon dioxide and
heat. The process also requires moisture and aeration to move the process along.
With the growing concern about the impact of agriculture on water quality and
heightened interest in managing agricultural by-products economically, the use of composting by
US farmers is increasing (Kashmanian & Rynk, 1998). National composting statistics are hard
capture due to the lack of policies requiring data collection from composting facilities (Themelis
& Arsova, 2015). Much of the smaller scale composting by US farmers is likely unreported due
to it being for personal rather than municipal use. The reported the total number of permitted
composting facilities in the US is 4,914 . The majority of these, 71%, compost
only yard trimmings . Food waste is accepted for processing by 347
composting operations . However, a growing number of composting
operations are upgrading their permits and infrastructure to process food waste.
Composting allows for better disposal of solid manure from livestock operations and can
also accommodate food waste along with it. This composting of the solid manure also allows for
better control of manure that is applied to the land. When it is matured via composting it is safer
for the environment and slowly releases its nutrients to the soil.
The use of compost has agricultural, environmental, economic, and social benefits. Some
of the agricultural benefits of the application of compost include: improvement of the physicalproperties of soils, enhancement of the chemical properties of soils, and improvement of the
biological properties of soils . Incorporating composts into compacted soils
improves root penetration and turf establishment in lawns, golf courses, and sports fields. The
water-holding capacity of the soil is increased by water binding to the newly introduced organic
matter, which means lower water requirement. Soil aeration is also improved, which allows
oxygen to reach the roots more readily . Compost can build up the nutrient
content of the soil, as it contains the major nutrients required by plants: N, P, K, Ca, Mg, and S.
The benefits of composting will last for more than one growing season because the nutrients are
slowly released . Compost not only benefits the soil, but also the surrounding
environment.
The environmental benefits of composting include pollution remediation and pollution
prevention ). Compost absorbs odors and degrades volatile organic
compounds. Compost also binds heavy metals and prevents them from migrating to water
resources or being absorbed by plants . Composting prevents methane
production in landfills by diverting organics for composting use. Composting raw manure can
minimize any potential environmental or nuisance problems. Raw manure is one of the primary
culprits in the pollution of waterways . Diverting this raw manure to
composting allows it to be repurposed and put back into the soil.
The social and economic benefits of composting include bringing higher prices for
organically grown crops and extending current landfill longevity. Compost helps keep plants
healthy by controlling weeds, providing a slow release of nutrients, and preventing soil loss
through erosion . Raw manure often contains weed seeds which are killed by
the heat of the compost pile. Healthier plants allow for higher prices which would benefit
farmers. Landfills would also fill up at a slower rate if more food waste was diverted to
composting. This would extend the lifetime of current landfills and put off the building of new
landfills.
However, given all the benefits of compost there are also some downsides. The
agricultural uses of compost remain low for several reasons. Firstly, compost tends to be heavy
and bulky, making it hard to transport . The nutrient value of compost is low
compared with that of chemical fertilizers, which may mean a lower nutrient release than farmers
would like . The nutrient composition of compost is also highly variable in
comparison to chemical fertilizers. Lastly, long-term and/or heavy application of composts to
agricultural soils has been found to result in salt, nutrient, or heavy metal accumulation and may
adversely affect plant growth, soil organisms, water quality, and animal and human health . In addition, if compost is not properly managed these drawbacks can become a
larger issue because the Nitrogen to Carbon ratio would not be appropriate for soil application.
If compost is not managed properly it can cause additional problems. When piles are
improperly constructed, including piles not turned regularly or piles with uneven sections, this
can provide refuge and breeding areas for some insects . This is because if some
areas of the pile are thinner than others, especially at the edge of the pile, the temperature would
be lower and habitable for insects. The attraction of insects could harm nearby plants.
Another sign that something is wrong with a compost pile is odor because ordinarily
composting should not smell. Any rotten or ammonia smells indicate that something is out of
balance with the compost . Rotten smells are an indication that the
pile has gone anaerobic and needs to be turned to have oxygen introduced. If the pile keeps
reverting to an anaerobic mode, it is time to explore different ingredient ratios or composting
styles . An ammonia-like smell can indicate that too many highNitrogen products have been added to the pile. The Nitrogen to Carbon ratio is a delicate balance
for composting to work properly. The proper ratio is 25-30 parts Carbon to 1 part Nitrogen, or
. Green products (grass clippings, corn meal, etc.) are the
main contributor of Nitrogen, whereas brown products (straw, sawdust, etc.) are the main
contributor of Carbon to the pile ).
Another common issue is that the compost does not heat up, which is an important part ofits proper functioning. It is important to realize that only freshly built or freshly turned piles wil
get hot and stagnant piles will not . Even if the carbon-nitrogen
and moisture balance in the new material is perfect there may not be enough of it, depending on
the size of the original heap, to support the mass of microbes needed to create a hot pile. In this
case, the pile either needs to be turned or new material needs to be added. For the compost to be
developed properly it must be cared for by someone who knows how to manage this balance.
They key to good compost is that its mature. Immature compost does more harm than
good because it has not been given time to properly transform and achieve a proper C:N ratio
. The amount of time needed to produce compost depends on several factors,
including the size of the compost pile, the types of materials, the surface area of the materials,
and the number of times the pile is turned. Large piles are limited by a person’s ability to turn the
compost. By turning more frequently (1-2 times per week), you will produce compost more
quickly. Waiting at least two weeks allows the center of the pile to heat up and promotes
maximum bacterial activity. The average composter turns the pile every 4-5 weeks (University of
. With frequent turning, compost can be ready in about 3 months,
depending on the time of year. In winter, the activity of the bacteria slows, and it is
recommended that the operator stop turning the pile to keep heat from escaping from the pile’s
center. In summer, warm temperatures encourage bacterial activity and the composting process is
quicker
