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Compost Science & Utilization
ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/ucsu20
Assessing the Quality of Compost Produced from
Human Hair and Pet Fur Waste
Tina Marie Waliczek, Merritt Drewery, Alex McMoran, Magdalena Eriksen &
Janet Hale
To cite this article: Tina Marie Waliczek, Merritt Drewery, Alex McMoran, Magdalena Eriksen &
Janet Hale (2023): Assessing the Quality of Compost Produced from Human Hair and Pet Fur
Waste, Compost Science & Utilization, DOI: 10.1080/1065657X.2023.2167749
To link to this article: https://doi.org/10.1080/1065657X.2023.2167749
Published online: 10 Mar 2023.
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RESEARCH ARTICLE
COMPOST SCIENCE & UTILIZATION
Assessing the Quality of Compost Produced from Human Hair and Pet
Fur Waste
Tina Marie Waliczeka, Merritt Drewerya, Alex McMoranb, Magdalena Eriksenb and Janet Haleb
aDepartment of Agricultural Sciences, Texas State University, San Marcos, Texas, USA; bDepartment of Finance and Economics, Texas
State University, San Marcos, Texas, USA
ABSTRACT
Composting is an effective waste management alternative that creates a horticultural and
agricultural based resource. Globally, large quantities of human hair and pet fur from salons,
barber shops, and groomers are disposed of, ultimately ending up in landfills. Thus,
incorporating human hair and pet fur into compost is a potential approach for waste
diversion. Human hair and pet fur are organic substances that contain nutrients essential
for plant growth, have moisture retention properties, and can insulate and stabilize soil.
Cumulatively, these properties suggest that hair and fur could be composted to create a
valuable product. However, human hair and pet fur also have the capacity to contain heavy
metals and/or chemicals from treatments. Accordingly, the purpose of this study was to
investigate the feasibility of composting human hair and pet fur as an alternative waste
management option without sacrificing compost quality standards or safety. To achieve this,
compost piles were created using 25% human hair or pet fur, 40% wood chips, and 35%
food waste. Piles were mixed twice weekly and monitored every 5–7 days for proper moisture
and temperatures in accordance with industry standards. In-vessel composters were used.
Piles cured for 4–8 weeks and the entire composting process lasted 5 months. Samples were
composited and tested by the Agricultural Analytical Services Laboratory’s U.S. Composting
Council’s Seal of Testing Approval Program at Pennsylvania State University. In this pilot
study, high quality composts were created, indicating that waste management industries
can potentially utilize human hair and pet fur as feedstocks to create desirable compost for
the horticultural and agricultural industries.
Introduction
The composting industry is well-known for its
ability to upcycle organic waste streams into valu-
able products. Composting is the natural decom-
position of organic matter into simpler compounds.
The end product, compost, is used as a soil
amendment in horticultural and agricultural appli-
cations as it improves soil productivity and con-
tains essential nutrients for plant growth (Emerson
2003). The U.S. compost industry is relatively
large (Sanders, Waliczek, Gandonou 2011); on a
national basis, the demand for compost is ten-fold
that of the supply (Slivka et al. 1992). Although
more recent estimates for market availability of
compost are not available from a peer-reviewed
source, using available metrics, it has been
reasonably demonstrated that there remains a dis-
parity between compost supply and demand in
the U.S. (BioCycle 2014).
Traditional organic matter ingredients in com-
post often include yard trimmings, food scraps,
paper, animal manure, and wood chips (Rynk
1992). While these ingredients would otherwise
be landfilled, there is a need to identify and
capitalize on additional waste streams as com-
post ingredients to further increase national
environmental stewardship and lessen the dis-
parity between compost demand and supply
(Walker, Williams, and Waliczek 2006; BioCycle
2014). Given results of similar studies, there is
potential for human hair and pet fur to be com-
posted, diverting their waste from landfills and
© 2023 Taylor & Francis Group, LLC
CONTACT Tina Marie Waliczek tc10@txstate.edu Department of Agricultural Sciences, Texas State University, 601 University Dr., San Marcos, TX
78666, USA
Data supporting the ndings reported within this study are available within the article presented here.
https://doi.org/10.1080/1065657X.2023.2167749
2 T. M. WALICZEK ETAL.
creating a valuable product for the horticulture
and agriculture industries (Hustvedt, Meier, and
Waliczek 2016).
Vast quantities of human hair waste are gen-
erated per year; it was recently estimated that
global annual production of hair is 6.9 × 105 tons
(Bheel et al. 2020), much of which would be
discarded as municipal waste solids (MSW) by
salons and barbershops. Similar estimates are not
available for pet fur but the animal care and
service sector is growing much faster than others
(U.S. Bureau of Labor 2021) and, anecdotally,
grooming services are increasingly prevalent,
likely in response to high pet ownership, espe-
cially that of dogs, in the U.S. (Applebaum, Peek,
and Zsembik 2020). Landfilling human hair and
pet fur is potentially problematic as they are
nitrogenous; thus, nitrates may leach into surface
or groundwater (Zheljazkov etal. 2008). Further,
in the U.S., landfills are the third largest source
of anthropogenic methane, accounting for 1.7%
of total greenhouse gas emissions (Environmental
Protection Agency (EPA) 2020). Many landfills
are within reach of their capacity at the current
rate of disposal. From 1990 to 2017, the U.S.
increased recovery of MSW for composting or
recycling by 2.8-fold (35% of MSW), but there
remains room for improvement as only 29% of
MSW is composted (Environmental Protection
Agency (EPA) 2019). Diverting organic waste (e.g.
human hair, pet fur) to processing facilities, such
as composting, will increase the life expectancy
of landfills (Beck 2010). Hair salons and pet
groomers can also capitalize on composting their
wastes. Consumers, especially millennials, are
driving the adoption of eco-efficiency because
they are more willing to purchase goods and
services from companies that are socially respon-
sible and aware of their environmental impact
(Heo and Muralidharan 2017). It would be advan-
tageous for hair salons and pet groomers to use
composting to become eco-efficient and reduce
fees for landfill waste hauling, which cost an
average of $55.36 per ton (Environmental
Research and Education Fund (EREF) 2019).
Historically, human hair and animal fur have
been used as fertilizers in China and India by
either mixing with cattle manure or applying
directly to the soil (Gupta 2014). The interest in
human hair and animal fur as soil amendments
recently received renewed attention. In a series
of experiments (Zheljazkov 2005; Zheljazkov etal.
2008; Zheljazkov, Stratton, and Sturz 2008), it was
demonstrated that non-composted human hair
waste could be a nutrient source for horticultural
and agricultural crops for two to three cropping
seasons but would likely benefit from the addition
of a chemical fertilizer or compost due to the
keratinaceous nature of hair and, thus, its resis-
tance to degradation (Ignatova etal. 1999). Animal
fur degrades quickly under controlled environ-
mental conditions and with inoculation of certain
keratinolytic microorganisms (Thanksaswamy
et al. 2018). To investigate if composting could
enhance degradation of human hair, Karak etal.
(2017) created compost piles containing human
hair waste, MSW, animal manure, tannery sludge,
and roadside pond sediment; the hair degraded
and a desirable, mature compost was created
within 10 weeks. Although pet fur has not been
investigated as a soil amendment to the best of
our knowledge, research with fur from livestock
has been conducted. Puente et al. (2021) com-
posted a mixture of fur waste obtained from tan-
neries; pruning remains; and an inoculum of
mature compost, animal residues, and molasses.
Overall, they obtained a mature compost, although
it should be noted they used a specialized desul-
furization process on the animal fur prior to com-
posting to reduce sulfide concentrations. The
extent of animal fur degradation was not quan-
tified in that study (Puente et al. 2021).
Wool waste as a soil amendment has been more
thoroughly investigated than either human hair or
pet fur. Previous research indicates that
non-composted wool in potted plants improves
water-holding capacity of the soil up to 20% and
acts as a slow-release fertilizer (Zheljazkov 2005;
Górecki and Górecki 2010). Further, wool acidifies
soil (Poston 2006; Zheljazkov et al. 2009), improv-
ing pH conditions for many garden and green-
house crops. In certain regions of the U.S., garden
soil amendments that hold moisture and lower the
pH of highly alkaline native soils may command
a high market value (Hustvedt, Meier, and Waliczek
2016), indicating that wool and products that have
similar characteristics as wool (e.g. human hair,
pet fur) may be value-added ingredients in compost.
COMPOST SCIENCE & UTILIZATION 3
While wool waste has been composted
(Pearson, Lu, and Gandhi 2004; Hustvedt, Meier,
and Waliczek 2016), the effect of composting
human hair and pet fur on compost quality has
received limited attention. There are many phys-
ical and chemical similarities between wool waste,
human hair, and pet fur, but key differences, such
as oil and potential contaminant content, justify
independent investigation of each as soil amend-
ments. Accordingly, the objective of this study
was to investigate if human hair and pet fur can
be composted as an alternative waste manage-
ment strategy without sacrificing safety or com-
post quality standards.
Materials and Methods
Hair and Fur Waste Material Collection
Human hair and pet fur were sampled from hair
and pet salon retailers in central Texas over a
6-month period. These wastes would have been
otherwise disposed of in a landfill. There were
no efforts to collect a specific distribution of
human hair from certain sexes, ethnicities, races,
or ages. Strands were of varying lengths, ranging
from ⅛ inch to 7 inches. Pet fur was obtained
from dogs and cats from groomers in varying
lengths, ranging from ⅛ inch to 4 inches. As
with human hair, we did not strive to collect a
specific distribution of pet fur from dogs versus
cats or from certain breeds. Non-compostable
contaminants were separated and discarded before
composting.
Other Organic Material Feedstocks Utilized
Woodchips of tree and shrub branches provided
by a local tree care company were used as a
carbon source in the compost. Therefore, size
of chips was relatively consistent, but species of
tree waste varied. Food waste was utilized as a
nitrogen and moisture source in the compost.
Food waste was collected from campus cafeterias
and varied in type, size, and consistency, where
some of the food waste was processed through
a grinder (yielding an even, fine-textured con-
sistency) while some consisted of whole
food parts.
Composting Protocols and Process
The protocol for each compost pile was based on
that of a previous study composting wool waste
(Hustvedt, Meier, and Waliczek 2016) and adjusted
based on limitations (nitrogen and moisture in
the final product) from that study. Two compost
piles were constructed and evaluated, each of
which included 25% human hair or pet fur; 40%
wood chips; and 35% food waste (by volume).
Approximately 0.75 yards3 of human hair or pet
fur; 1.2 yards3 of wood chips; and 1 yards3 of
food waste were used to create 3 yards3 total of
composting material within each container. A
control pile was not included in this study as, in
compost quality tests, compost samples are com-
pared to overall standards for the industry.
In-Vessel Compost Units
Compost piles were contained and managed in
separate Green Mountain Technology Earth Tubs
(Green Mountain Technologies, Bainbridge Island,
WA) each of which had a 3 yards3 capacity. Earth
Tubs are in-vessel composters that allow for com-
posting convenience in smaller spaces with odor
management and control over potential leachate
contaminants. Utilizing the containers limited the
scale of the study to the capacity of the in-vessel
compost units but prevented possible heavy metal
or chemical contamination of soils from the
human hair and/or pet fur.
Compost Monitoring and Maintenance
The temperature, pH, moisture, and maturity of
each compost pile were monitored and recorded
twice weekly. Piles were turned using the in-vessel
unit augers. Composting and curing of materials
took approximately 3 months.
Compost piles were maintained at ≥54.4 °C for
a minimum of 3 days to kill weed seeds and
pathogens (Dougherty 1999) and were measured
and monitored with a 152 cm Fast Response
Compost Thermometer (ReoTemp Instrument
Corporations, San Diego, CA). Moisture levels
were measured and monitored with a 152 cm
Compost Moisture Meter (ReoTemp Instrument
Corporations, San Diego, CA), as well as with a
4 T. M. WALICZEK ETAL.
“feel” test. The feel test involved taking a handful
of compost, squeezing it, and determining
whether it felt like a moist sponge; if the sample
did not feel wet to the touch, then it was too
dry and, if water could be squeezed out, then it
was too wet (Rynk 1992). Acidity and alkalinity
(pH) were measured and recorded with a hand-
held Keyway® Soil pH sensor (Wyckoff, NJ).
Oxygen levels were monitored and measured with
an oxygen monitor (Model No. 0-21, Demista
Instruments, Arlington Heights, IL).
Cured Compost
The compost was in the curing stage when there
was a substantial and sustained reduction in pile
temperatures within the range of 10.0–40.6 °C
(Rynk 1992). The compost was cured in the same
piles where they were built and within the
in-vessel units. The curing stage lasted approxi-
mately 4–6 weeks which is typical (Rynk 1992).
Compost Sampling
After curing, samples were collected from each
compost pile with care taken to ensure they were
representative of the initial proportions of each
ingredients. Sampling was as specified by the
Agricultural Analytical Services Laboratory at
Pennsylvania State University (2021). Specifically,
subsamples from each compost pile were col-
lected from three different depths at five loca-
tions. These subsamples were composited to
create two 1.89 L samples representative of each
pile and then analyzed according to the
Agricultural Analytical Services Laboratory’s U.S.
Composting Council’s STA Program at
Pennsylvania State University (University Park,
PA) for: pH, soluble salt content or electrical
conductivity, moisture, organic matter, total nitro-
gen, total carbon, carbon to nitrogen ratio, phos-
phorus, potassium, magnesium, and metals
(aluminum, copper, and zinc). Bioassay and res-
pirometry tests were also conducted to observe
maturity and stability of the compost samples
(U.S. Composting Council Seal of Testing
Assurance 2010; Montoya, Waliczek, and Abbott
2013; Meier, Waliczek, and Abbott 2014;
Pennsylvania State University 2021).
The percent solids and percent moisture content
of the finished compost was measured by weighing
a sample and then drying it at 70 (± 5)°C and
then re-weighed (Test Methods for the Examination
of Composting and Compost [TMECC] 2002).
The remaining dry solids fraction represented the
total solids and the evaporated fraction represented
the percent moisture (TMECC 2002).
The pH of finished compost was measured by
making a slurry of compost and deionized water
and then blending to a ratio of 1:5 (TMECC
2002). The sample was then shaken for 20 min
at room temperature to allow the salts to solubi-
lize in the deionized water and pH was measured
with an electrometric pH meter (TMECC 2002).
Electrical conductivity (soluble salts) were mea-
sured by taking the electrical conductivity in a
1:5 (compost:water, weight ratio) slurry and was
measured in units of mmhos/cm (TMECC 2002).
The percent organic matter of the finished
compost was measured by using the Loss-On-
Ignition Organic Matter Method which is a direct
determination method that indicates organic mat-
ter content by quantifying the amount of solid
material combusted relative to the original dried
sample (TMECC 2002). The nitrogen, organic
nitrogen, and ammonium nitrogen content of the
finished compost was determined by using the
methodologies specified in the Test Methods for
the Examination of Composting and Compost
(2002), specifically, the Total Kjeldahl Nitrogen
Semi-Micro Kjeldahl technique (TMECC 2002).
Phosphorus (P) and potassium (K) contents were
measured by digesting an air-dried, milled sample
and determining the phosphorus or potassium
content using inductively coupled plasma emis-
sion spectroscopy (ICP) (TMECC 2002).
The total carbon content of the finished com-
post in this study was measured by the
Combustion with CO2 Detection method (TMECC
2002). This method uses a carbon analyzer (Leco
CR-12) to determine total organic carbon in com-
post (TMECC 2002). The analyzer operates on
the principle of total combustion of a sample in
an oxygen-rich atmosphere of a 1371 °C resistance
furnace (TMECC 2002). The CO2 produced by
the combustion is swept into an oxygen stream
through anhydrone tubes to scrub H2O vapor
from the stream (TMECC 2002). The CO2 stream
COMPOST SCIENCE & UTILIZATION 5
is then fed into the infrared detector and the
amount of CO2 produced is measured
(TMECC 2002).
The maturity (bioassay) test provides a screen
for the presence of phytotoxins in compost based
on seedling emergence and seedling vigor relative
to a positive control and provides an assessment
of compost maturity, where the Emergence (per-
cent of control) and Seedling Vigor (percent of
control) of the finished compost was determined
by using the methodologies specified in the U.S.
Compost Council Test Methods for the
Examination of Composting and Compost (2002).
Respirometry of the finished compost was
determined by using the methodologies specified
in the Test Methods for the Examination of
Composting and Compost (2002), which assumes
optimal conditions for microbial activity are pres-
ent including temperature, moisture, and nutri-
ents and that toxic components that would inhibit
microbial respiration are absent (TMECC 2002).
Respirometry: Carbon Dioxide (CO2) Evolution
Rate (mg CO2-C/g organic matter/day) provides
a measurement of the relative microbial activity
in a compost and can, thus, be used as an esti-
mate of compost stability (TMECC 2002).
Data Analysis
Compost quality measures are reported as fre-
quencies and descriptive data.
Results and Discussion
Approximately 1.5 yards3 of stabilized material
was created for both human hair and pet fur
composts (original volume of 3 yards3); this was
expected as, during composting, materials often
reduce to ≥50% of their original volume. Compost
quality results indicated that compost piles con-
taining either human hair or pet fur were within
acceptable ranges of parameters for the U.S. and
European Union (Table 1; U.S. Composting
Council Seal of Testing Assurance 2010;
Ozores-Hampton 2017; ECN-QAS 2018) with the
exception of organic matter for either compost
containing human hair or pet fur and solids/
moisture for the human hair compost. Further,
compost stability, measured as mg CO2-C/g
organic matter/day, was 3.1 for compost contain-
ing human hair; this corresponds with a “stable”
classification although <2 is a “very stable” com-
post and is, thus, optimal (U.S. Composting
Council Seal of Testing Assurance 2010). This is
likely a consequence of the previously noted low
organic matter content, although the same out-
come was not observed for compost containing
pet fur (1.5 mg CO2-C/g organic matter/day).
Recommended moisture of compost is 30%
(dry matter basis) − 60% (as-is basis) (Ozores-
Hampton 2017); pet fur compost was within the
optimal range at 43.9% moisture (as-is) while
human hair compost was on the lower end of
the range with a moisture content of 35.8%
(as-is). Low moisture was likely at least partially
a consequence of samples drying during and
after shipping to the compost testing facility as
well as due to hair being hygroscopic. As the
moisture was low for the human hair compost,
the solids were higher than desired. We partially
attribute this to clumping of longer fibers of
human hair in compost pile and recommend that
hair used for composting is screened, cut into
small pieces, or included at a lower rate to
account for this. Given past research indicating
hair or fur readily degrades during composting
or under similar conditions as the composting
process (Karak etal. 2017; Thanksaswamy et al.
2018), we anticipate the hair and fur in our
study degraded; however, the human hair was
physically longer than the pet fur which may
explain our observations of low moisture and
high solids for the human hair compost only. In
past research with wool waste, moisture within
compost piles was on the lower range of accept-
ability due to the hygroscopic nature of wool
(Poston 2006; Hustvedt, Meier, and Waliczek
2016); to counteract this, an ingredient with high
moisture content (i.e. invasive aquatic plants)
was incorporated to offset moisture absorption
by the wool waste and maintain an ideal mois-
ture content. Therefore, when using fibrous
materials that absorb moisture (e.g. wool, human
hair, pet fur) as compost ingredients, it is
important to consider the moisture content of
the other ingredients to ensure adequate mois-
ture is available for decomposition (Hustvedt,
Meier, and Waliczek 2016). Noting the lower
6 T. M. WALICZEK ETAL.
percentages of organic matter in the quality
reports for both human hair and pet fur com-
posts, it is recommended that compost piles
containing hair or fur be supplemented with
increased quantities of nitrogen-rich feedstocks,
such as food waste, manures, and/or fish waste
as this has demonstrated favorable results in pre-
vious composting trials with sargassum (Walsh
and Waliczek, 2020).
We recommend that human hair and long
fibers of pet fur be combed or sorted and evenly
distributed into in-vessel composters after other
ingredients (e.g. wood chips, food waste) are
mixed. In our study, both augers were damaged
from large masses of human hair twisting and
becoming compacted around them. In a previous
investigation into the potential of human hair as
a compost ingredient, the researchers cut the hair
into 1–2 mm pieces before composting and did
not report issues with compaction (Karak et al.
2017). Similarly, another study using wool waste
as a compost ingredient demonstrated that sep-
aration was necessary to obtain a more fibrous,
less clumped product (Hustvedt, Meier, and
Waliczek 2016). This compaction and clumping
are limitations to using materials such as long
fibers of wool, human hair, or pet fur as manual
separation is time consuming.
Another potential challenge to incorporating
human hair or pet fur into compost could be
consumer perception or attitude. Clumps of
human hair were physically apparent in the fin-
ished compost. In an unpublished study, ten
lead-user gardeners were provided compost con-
taining physically apparent waste wool and, after
utilizing it in their gardens, were asked about
their perceptions and experiences (William
Glenn, report to authors, 7/25/2021); overall,
only one (10%) described the appearance of the
compost in a negative light (“weird” and may
“gross some people out”) whereas others were
neutral and three (30%) described it positively
(“richer and thicker” [than normal compost]).
Finally, in response to a prompt about additional
questions or comments, one participant said “I
love the idea of a wooly compost or a dog hair
or human hair… whatever!” (William Glenn,
report to authors, 7/25/2021). Although the
compost in that study contained waste wool, it
is reasonable to expect similar outcomes for a
compost containing human hair or pet fur.
Ultimately, we recommend a study evaluating
Table 1. Quality of composts including human hair and pet fur as experimental ingredients.
Variable (units)a
Compost containing
human hair
Compost containing
pet fur Optimal range, U.S.bOptimal range, EUc
pH 8.0 7.6 5.0–8.0 4.0–9.0
Electrical conductivity (dS/m) 4.81 4.04 <6 --
Solids (%) 64.2 56.1 40 (wet) − 70 (dry) --
Moisture (%) 35.8 43.9 30 (dry) − 60 (wet) --
Organic matter (%) 29.8 26.9 40-60 ≥15
Total nitrogen (%) 1.3 1.4 0.5-6.0 --
Carbon (%) 19.3 18.7 <54* --
Carbon:nitrogen ratio 14.40 13.00 10-25 --
Phosphorus (%) 0.41 0.36 0.2-0.3 --
Potassium (%) 0.48 0.45 0.10-3.5 --
Arsenic (mg/kg) 3.5 5.8 <41 --
Cadmium (mg/kg) <0.5 <0.5 <15 <1.3
Copper (mg/kg) 15.3 14.4 <450 <300
Lead (mg/kg) 4.7 4.8 <300 <130
Mercury (mg/kg) 0.03 0.02 <17 <0.45
Molybdenum (mg/kg) <1.5 <1.5 <75 --
Nickel (mg/kg) 4.0 3.5 <50 --
Selenium (mg/kg) <2.5 <2.5 <100 --
Zinc (mg/kg) 53.9 81.6 <900 <600
Stability
mg CO2-C/g volatile solids/day 0.9 0.4 <2 --
mg CO2-C/g organic matter/day 3.1 1.5 <2* --
Maturity
Seed emergence, % control 100 100 >90* --
Seedling vigor, % control 100 100 >95* --
aThe variables of pH, electrical conductivity, moisture, and maturity vigor are reported on an as-is (fresh) basis while the remaining variables are reported
on a dry matter basis.
bOptimal ranges from Ozores-Hampton (2017) or from U.S. Composting Council (2010) if denoted with a *.
cOptimal ranges from ECN-QAS (2018).
COMPOST SCIENCE & UTILIZATION 7
consumer perception and attitude toward com-
post visibly containing human hair or pet fur.
As first posited by Zheljazkov (2005), soil
amendments containing human hair, pet fur, or
wool waste may be better suited for crops grown
for production of secondary metabolites (e.g.
essential oils) or ornamentals not used for direct
human consumption.
In our study, in-vessel composters were utilized
to prevent potential leaching of heavy metals
from the human hair and pet fur as our a priori
hypothesis was that the heavy metals from dyes,
treatments, and pharmaceuticals may contaminate
our experimental ingredients, especially for the
human hair compost. This hypothesis was based
on previous experiments that demonstrate that
human hair can absorb mercury, copper, cad-
mium, and silver from aqueous solutions (Tan,
Chia, and Teo 1985; Krishnan, Cancilla, and
Jervis 1988), and that metals can bioaccumulate
in humans and animals (Khazaee et al. 2016).
However, heavy metals of either compost pile did
not exceed optimal ranges or thresholds standard
for the U.S. (Ozores-Hampton 2017; U.S.
Composting Council Seal of Testing Assurance
2010) or EU (ECN-QAS 2018), indicating human
hair and pet fur can safely be included as com-
post ingredients up to 25% of the total biomass
(by volume) without concerns for heavy metal
content. Other potential non-heavy metal con-
taminants deserve further investigation, however.
Conclusion
Our data add to a growing repository of literature
that seeks to identify alternative waste manage-
ment strategies for organic streams that would
otherwise be landfilled. Our data suggest human
hair and pet fur can be safely incorporated in
compost at up to 25% of the volume of the total
biomass without concerns for heavy metal content.
Thus, future studies should increase in scale while
determining optimal inclusion of human hair and
pet fur wastes in finished compost by adjusting
inclusion of human hair and pet fur to alleviate
the issues with organic matter and moisture/solids
content. Depending on length of the human hair
or pet fur fibers, manual separation or combing
may be necessary prior to composting to facilitate
the composting process. Finally, it would also be
interesting to quantify the extent of hair/fur deg-
radation throughout the composting process and
to determine environmental conditions that accel-
erate this degradation.
Funding
e authors do not have a funding source to disclose.
Disclosure statement
e authors do not declare a nancial conict of interest.
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