Over
25,000 dead deer and numerous carcasses of other animals such as raccoons,
coyote and fox are managed annually by the New York State Department of
Transportation (NYSDOT). NYSDOT maintains and operates a 15,656 mile highway system of
interstates, expressways and collectors which comprises about 15 percent of NYS's total of 111,000 miles of highway. The 25,000 dead deer managed annually by
NYSDOT do not account for deer killed on county and local roads that must be
managed by local highway departments.
Disposal
options for these carcasses are limited and appropriate disposal is
expensive. Carcasses are often left by
the road or dumped into low areas. Over
the past several years, the Cornell Waste Management Institute (CWMI) has
worked with dairy farms to manage mortalities through on-site static pile
composting. Workshops and demonstrations
held at these sites have generated substantial interest in the process. The NYS Department
of Environmental Conservation (NYSDEC), local and regional Departments of
Health, Soil and Water committees and Natural Resources Conservation Service
(NRCS) staff have attended workshops and become familiar with the process. Regional and local NYSDOT personnel
have attended workshops and indicated interest in trying composting to manage
road-killed deer. In response,
composting of road-killed deer is being piloted under CWMI guidance at several
NYSDOT facilities in
Current NYSDOT practices include contracting with service
providers to pick up and dispose of the animals, dragging animals further off
the road or placing them in pits and depressions off road sides. This is becoming costly and inefficient and
service providers do not always have a legal and environmentally sound plan for
disposal. Contractors are paid between
$30 and $80 per deer for pick-up and disposal (Rick McKeon, personal
communication, NYSDOT) and in FY's 2000-2002 this totaled just over $1.1
million. Landfills generally will not
take carcasses and when they do it tends to be restricted, so the NYSDOT is
left with limited and/or costly disposal options.
For years NYSDOT has been able to leave animals
where they were killed or drag them to the side of the road. In more populated areas disposal into a pit or
in low areas was often practiced. These
methods are becoming less acceptable as rural areas become more populated and
there is increased concern for environmental quality. Water quality can become compromised when
animals decompose on or below ground. As
carcasses are buried or put in ravines, there is a good chance that water
quality will be affected and it could become a public health issue as pets and
people may come in contact with the carcasses.
Soil and water regional water quality groups are concerned about the
ground and surface water ramifications and may be interested in cooperating in
piloting of static piles for carcass disposal in several regions.
Passively aerated static pile composting is proving to be a good
method of managing these wastes. It is
simple, takes less time than dragging a carcass out back, uses equipment and
materials used in daily operations and is cost effective. This method helps protect ground and surface
water by keeping the carcasses out of contact with water and by reducing
pathogens in properly managed piles and it reduces nuisance and odors.
The
effectiveness of inactivating pathogens through composting is generally
assessed by monitoring the reduction in indicator organisms. Salmonella
and fecal coliform are the usual indicator organisms. These are the organisms that the USEPA
requires for evaluation of the hygienic quality of sewage sludges. It is widely recognized that the sensitivity
of different pathogenic organism to heat varies significantly and questions
have been raised about the use of the current indicator organisms. Evaluation of the effectiveness of static
pile composting to inactivate pathogens in road-killed carcasses requires
identification of the pathogens that might be present and analysis of their
sensitivity to inactivation by heating.
That, combined with time/temperature data from the compost piles, will
provide the information needed to assess the hygienic quality of the compost
product.
Chronic Wasting Disease (CWD) is a prion disease that is of concern in wild populations. There
is no evidence to show whether CWD would be killed in the composting process.
Compost temperatures are not high enough to inactive prions,
but it is possible that microbial and enzymatic activity could (Langeveld, et al; Kirill, et
al.). Whether or not composting
inactivates prions, through the process of composting
the mortalities would be collected and managed to prevent nuisances such as
odor. The
compost would be much more amenable to incineration than the untreated
carcasses if incineration were required.
It would also be a more esthetically acceptable material than carcasses. Guidance materials developed for NYSDOT
personnel will address CWD after consultation with the NYS Departments of
Health and of Environmental Conservation.
Very
little work has been done to assess the effectiveness of pathogen-kill in
static pile mortality composting. The
reduction of pathogens through composting due to elevated temperatures and
microbial competition has been documented for intensively managed (frequently
turned) compost piles handling other types of wastes. Even for turned piles, little information
exists for carcass composts. Some
research done in
Composting
mortalities in turned piles requires more labor, machinery and management than
static pile composting, thus increasing costs.
It also provides the potential for release of odors if turned too early
in the process. Static pile mortality composting
is a more easily managed technique. By
properly constructing the compost pile to allow for adequate natural aeration,
mortality composting can be completed on intact animals with little or no
turning. The process appears to be
effective if the animals are enclosed in chunky carbonaceous material such as
wood chips.
There is a need to
evaluate the effectiveness of static pile composting of mortalities bulked with
wood chips. Wood chips are an
appropriate and easily available material for use in NYSDOT compost piles. Temperatures achieved in static pile
composting suggest an adequate degree and duration of high temperatures to
significantly reduce the survival of many pathogenic organisms, at least in the
core of the piles. Preliminary
investigations by CWMI at several piles in NYS indicate that temperatures of
140 degrees F are reached and that temperatures over 130 degrees are sustained
for more than 6 weeks. However,
temperature and pathogen kill in static compost piles have not been studied to
the extent needed to provide confidence.
Questions such as “What is the thermal stability/sensitivity of the
pathogens that might be present in road-killed wildlife in NYS?”, “Are there
worker health and safety issues?”, “When is the process finished?” and “Where
can the finished product be used?” still need to be addressed.
NYSDOT and local
highway department staff who work with carcasses need
health and safety information pertaining not only to carcass-borne pathogens,
but also on tick-borne diseases such as Lyme disease,
Rocky Mountain Spotted Fever, babesiosis and ehrlichisosis.
Preliminary indications based on discussion with
Those
responsible for managing animal mortalities need sound information and guidance
on managing carcasses in static compost piles.
Some guidance has been developed by NYSDOT Region 8 staff based on
experience with some pilot piles. The
NYSDEC has also developed some materials and there are standards developed by
the NRCS for farm mortality management that are relevant. These provide a basis from which to work to
develop materials based on the additional work proposed. A fact sheet and posters developed as part of
our work with on-farm mortalities will also provide useful input to developing
guidance materials for composting of road-killed animals (these can be viewed
and downloaded from:
http://compost.css.cornell.edu/naturalrenderingFS.pdf. Field demonstrations are an effective means
of sharing information, especially when used in combination with educational
materials available on the WWW and printed materials. They provide a means of reaching not only
those at NYSDOT who might implement composting, but also other interested
parties such as local highway personnel, state and local environmental and
health staff, soil and water staff and others.
Bringing these players together is helpful in avoiding potential conflicts
based on misunderstanding of the process.
Under
CWMI guidance, six static compost piles will be established. Three will be at
NYSDOT facilities across NYS and will serve as sites for demonstrations and
monitoring. Three will be at a location selected by CWMI where more intensive
monitoring can be carried out (these are the “research piles”). All piles will contain several deer carcasses
bedded in wood chips. Pile design,
construction (such as placement of carcasses) and dimensions will be the same
for all piles. The wood chips used in
the 3 demonstration locations will be obtained locally. The 3 research piles will be constructed
using the same wood chips. The research piles will be comprised of 4 adult
deer. Indicator organisms will be placed
by CWMI into the carcasses in the
research piles in a manner that enables them to be recovered for sampling. Use of nylon mesh bags containing substrate
that has been seeded with the desired microorganism has been successfully used
in compost research.
Training
shall be provided by CWMI to NYSDOT
maintenance personnel at the three NYSDOT demonstration locations to enable
them to manage and monitor the piles.
Automated temperature probes shall be provided by CWMI. Use of automated temperature monitoring
devices at all 6 piles will enable us to collect data on the time/temperature
profile of the piles, which is a key to pathogen inactivation. Temperature probes shall be placed by CWMI in
several areas within each compost pile including within one of the deer
carcasses in each pile in order to determine what temperatures are achieved
within the carcass.
Consultation
with faculty at the Vet College, the Cornell Department of Natural Resources
(DNR), NYSDEC, NYS Department of Health Services (NYSDOH), US Fish and Wildlife
Service (USFWS), US Department of Agriculture (USDA) and the U.S. Environmental
Protection Agency (USEPA) will help to identify the pathogens of concern in
road-killed animals including deer, coyote, fox, raccoons, bear, moose, beaver
as well as domestic dogs and cats. CWMI
has met with many of these parties over the past year to discuss composting of
road-killed animals and have established relationships that will enable CWMI to
work with them on this project. (CWMI
was asked to attend a USEPA hosted meeting to discuss the development of
methods to manage disposal of mass mortalities such as experienced in
A
literature review shall be conducted by CWMI to find data concerning the
thermal stability of the pathogens identified.
The results will be compared with data for pathogenic organisms present
in sewage sludges to determine if those likely present in wildlife are more
resistant than those present in sewage sludges.
The information and professional opinion will help to determine what
pathogens or indicator organisms should be tested for in the composts. It is suggested that Mycobacterium enterra and Geobacillus stearothermophilus
may be appropriate indicators with which to seed the piles.
Under
the direction of CWMI, results shall be statistically analyzed and interpreted
so that appropriate guidance can be developed. Field demonstrations shall be conducted by
CWMI at each NYSDOT demonstration site to share the information gained. Guidance and educational materials shall be
generated and disseminated and presentations shall be made to both to NYSDOT
and to local NYS highway personnel.
Reference cited:
Keener, H.M., D.L. Elwell, M.J. Monnin. Procedures and Equations for Sizing of
Structures and Windrows for Composting Animal Mortalities. 2000. Applied
Engineering in Agriculture 16(6): 681-692.
Langeveld,
Jan P. M. Jeng-Jie Wang, Dick F. M., Van de Wiel, Giles C., Shih, G., Garssen,
J., Bossers, A., and Shih, J. 2003. Enzymatic
Degradation of Prion Protein in Brain Stem from
Infected Cattle and Sheep. JID 188 (1 December). 1782
Tsiroulnikov, Kirill Human Rezai,
Elisaveta Bonch-Osmolovskaya,
Peter Nedkov, Adriana Gousterova,
Valeä Rie Cueff, Anne Godfroy, Georges Barbier, Franc Ois Meätro, Jean-Marc Chobert, Pascal
Clayette, Dominique Dormont,
Jeanne Grosclaude, and Thomas Haertleä.
2004. Hydrolysis of the Amyloid Prion Protein and
Nonpathogenic Meat and Bone Meal by Anaerobic Thermophilic
Prokaryotes and Streptomyces Subspecies. J. Agric. Food Chem. 52,