Full text of DOI:10.1093/japr/11.3.282

2002 Poultry Science Association, Inc.
Effect of Poultry Litter Amendment
on Hatchery Waste Composting
1
K. C. Das, M. Y. Minkara, N. D. Melear, and E. W. Tollner
Department of Biological and Agricultural Engineering
University of Georgia, Athens, Georgia 30602-4435
Primary Audience: Researchers, Hatchery Managers, Poultry Industry Environmental
Managers, Extension Agents, Health Officials, Regulators
SUMMARY
Continuous growth of the poultry industry is accompanied by a need to manage large quantities
of by-products such as hatchery wastes. Hatchery wastes contain nonfertile eggs, dead chicks, and
broken eggshells. Although rendering plants currently use a portion of hatchery waste, large
amounts are sent to landfills, which cost the poultry industry millions of dollars each year. As a
potential alternative to landfilling, composting was investigated as a method to convert the nutrient
rich waste into a stable product for beneficial use.
Hatchery waste was amended with sawdust and yard trimmings and in one treatment with
poultry litter (broiler) to determine the feasibility of composting hatchery wastes. Hatchery waste
co-composted with poultry litter maintained higher temperatures during the experiment resulting
in higher dry matter and volatile solids and greater losses of nitrogen by the end of the composting
process. The composted product containing poultry litter had higher levels of plant nutrients such
as P, K, and many of the other micronutrients than the product without poultry litter. Both
treatments were effective in eliminating 99.99% of Escherichia coli; however, more Salmonella
reduction was observed in the treatment containing poultry litter than the treatment without
poultry litter.
Key words: compost, pathogen reduction, hatchery waste, waste management
2002 J. Appl. Poult. Res. 11:282–290
In most cases, more than 65% of these hatchery
wastes end up in landfills [3].
DESCRIPTION OF PROBLEM
Broiler chick production in the United
States has increased to new highs every year
since 1975. In 2001, 9.01 billion total chicks
were hatched in the United States [1], including
Hatchery wastes consist of nonfertile eggs,
eggshells, egg membranes, and dead embryos
and chicks. Traditional methods of hatchery
waste disposal include landfill, land applica-
tion, rendering, and egg wringing. Egg wring-
ing is a process of centrifugally separating the
liquid proteins, representing 40% by weight,
from the eggshell and dehydrating and con-
verting it into an animal protein feed additive
[4]. The remaining solid fraction has no bene-
1
.33 billion in the state of Georgia. This in-
crease in hatchery production has resulted in
increasing amounts of hatchery wastes that
have to be managed appropriately. It is esti-
mated that annual hatchery waste generated in
the United States amounts to 140,000 tons [2].
1
To whom correspondence should be addressed: kdas@engr.uga.edu.

DAS ET AL.: HATCHERY WASTE COMPOSTING
283
TABLE 1. Properties of ingredients used for composting hatchery wasteA
Moisture
content (%)
Volatile solids
content (%)
C:N
Ratio
Bulk density
(kg/m )
3
Ingredient
N (%)
C (%)
Hatchery waste
Sawdust
Yard trimmings
Poultry litter
32.5 (2.25)
46.5 (4.14)
29.9 (3.30)
23.0 (1.35)
20.2 (3.56)
99.8 (1.85)
75.9 (3.56)
83.6 (5.65)
1.90 (0.45)
0.12 (0.03)
0.61 (0.05)
3.82 (0.37)
15.5 (3.05)
52.6 (1.29)
31.7 (0.27)
39.0 (1.35)
8.1:1
971 (15.4)
290 (20.6)
262 (10.4)
422 (23.7)
438:1
52.4:1
10.2:1
AValues in parentheses are standard deviations.
ficial use and is typically sent to landfills. Land
application of the hatchery waste, which used
to be a common disposal practice [5] has been
recently banned in Georgia because of prob-
lems with odors and inability to routinely incor-
porate the material into the soil [6].
of the composting material thus facilitating air-
flow into the compost matrix that is required
for microbial respiration and heat removal.
A pilot-scale field experiment (two treat-
ments × three replicates) was conducted using
3 × 2.5 × 2-m enclosed bins serving as compost
bioreactors. The bins were built on a concrete
base that was inclined to one side to prevent
accumulation of any leachate at the bottom of
the bin. The bins were constructed with treated
lumber with the side boards stacked on top
of each other leaving small gaps between the
boards to allow air to enter the compost matrix.
The first treatment was prepared by mixing
hatchery waste with sawdust and yard trim-
mings to provide a ratio of 3:2:1 by volume
Composting has successfully been used to
dispose of and convert agricultural and animal
wastes, such as poultry mortalities and litter,
into a useful product [7]. Therefore, compost-
ing technology may be a feasible alternative to
convert hatchery waste that is rich in nitrogen
and calcium into a stable product for use as a
soil amendment and organic fertilizer. Before
composting technology can be commercially
adopted, it is necessary to determine the or-
ganic matter decomposition rate, or time re-
quired to compost, and the quality of the com-
posted product in terms of nutrient content and
pathogen reduction. In order to evaluate com-
posting as a feasible treatment option, a re-
search project was conducted to 1) assess the
rate of decomposition of hatchery wastes, 2)
determine the effect of the use of poultry litter
(
1:6:11 dry weight). The second treatment was
prepared by blending hatchery waste with saw-
dust, yard trimmings, and poultry litter (PL) to
provide a ratio of 2:1:1:2 by volume (1:8:7:2
dry weight). Treatments were designed to con-
tain the same content of hatchery waste (6.0%
dry weight) in the completed mix. This recipe
was developed to maximize the use of hatchery
waste while maintaining optimum conditions
to initiate microbial activity (C:N above 10:1,
volatile solids content above 40%, and bulk
(
obtained from broiler chicken houses) as an
amendment in the composting process, 3) eval-
uate the pathogen reduction capability of the
composting process, and 4) determine the nutri-
ent content of the composted product.
3
density around 600 kg/m ).
Water was added to both treatments to in-
crease the moisture content (MC) by 10 to 15%
in order to enhance microbial activity. Passive
aeration and mixing (once every week for the
first 2 wk and once every 2 or 3 wk for the
following weeks) were the only mechanisms
of oxygen supply to the composting matrix.
Mixing was conducted by removing the com-
post from the bins, and then adding water and
homogenizing the compost with a loader, and
reloading the compost back into the bins.
MATERIALS AND METHODS
Materials and Procedure
Because hatchery wastes have a low C to N
ratio (C:N) value of 8.1:1, they were composted
with sawdust having a high C:N ratio of 438:1
(
Table 1). Because of the high bulk density of
3
hatchery waste (971 kg/m ), yard trimmings
3
(
bulk density of 262 kg/m ) were added to in-
crease the porosity and reduce the bulk density

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FIGURE 1. Moisture level (above) and temperature (below) in hatchery waste mixes during composting. PL =
poultry litter. Arrows indicate days when compost was homogenized and water was added.
Experimental Design and
Analytical Methods
five mixing events during composting. Samples
were analyzed for moisture, volatile solids (VS),
total C, total N, pH, stability index (i.e., oxygen
uptake rate), and bulk density. Total counts of
E. coli and the presence of Salmonella were
measured in samples obtained at the start and
the end of composting. Average elemental con-
centrations (nutrients and metals) of the three
replicates in each treatment were determined at
the end of the composting period.
Experimental design and data analysis was
based on a completely randomized design of two
treatments with three replicates each. Compost
temperature was measured three times a week
using type T thermocouples positioned at the
middle of each bioreactor. Oxygen concentration
within the composting matrix was measured
three times each week using a portable oxygen
analyzer [8].
A 250-g sample of wet compost was placed
in a forced-draft oven (104°C) for 72 h or until
no change occurred in weight to measure the
Compost samples from each bioreactor were
taken at the start of composting and at the end of

DAS ET AL.: HATCHERY WASTE COMPOSTING
285
FIGURE 2. Oxygen concentration (above) and stability index (below) in hatchery waste mixes during composting.
PL = poultry litter. Arrows indicate days when compost was homogenized and water was added.
moisture content [9]. The dry sample was then
ground thoroughly (150 mesh), mixed, and
stored in airtight bags for further analysis. Ap-
proximately 5-g subsample was combusted at
using the EPA Method 3052 [13] with 10 mL
of trace metal grade nitric acid and then analyzed
based on the EPA Method 200.8 [14] by using an
inductively coupled plasma mass spectrometer.
5
50°C for 6 h to determine VS concentration
Plasma Mass Spectrometer
[10]. A water extract of 1:2 (mass basis) of com-
post to water was used to determine pH [11].
Approximately a 250-mg dried compost sub-
sample was used for C, S, and N determinations
by a combustion analyzer [12]. Micronutrients
and metals were measured in a 250-mg dried
compost sample after microwave digestion by
The stability index (SI) of the compost was
measured using the procedure described by Ian-
notti et al. [15]. The sample was standardized
for particle size (<9.5 mm) and moisture content
(50%) and incubated (37°C) for 16 h under aero-
bic conditions to build the microbial populations

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TABLE 2. Initial and final properties of hatchery waste composted with or without poultry litter (PL) as an amendment
Treatment with PL Treatment without PL
Property
Initial
Final
Initial
Final
A
Moisture content, %
38.6 (3.17)
59.9 (2.28)
548 (19.4)
21.9 (3.44)
34.2 (1.27)
538 (36.3)
0.95 (0.09)
21.2 (1.19)
17.7:1
40.2 (1.10)
46.5 (1.24)
612 (26.4)
1.84 (0.07)
26.4 (2.81)
12.4:1
7.1 (0.03)
42,303 (1,162)
+ + +
N/A
32.0 (0.52)
25.4 (0.81)
645 (6.91)
0.63 (0.15)
16.9 (2.44)
23.6:1
Volatile solids content, %
3
Bulk density, kg/m
a
b
N, %
C, %
2.70 (0.43)
30.2 (2.05)
12.3:1
C/N Ratio
PH
7.4 (0.10)
8.8 (0.14)
13.2 (0.44)
− − −
33.5 (5.19)a
7.4 (0.09)
9.7 (14.6)
− + +
17.3 (2.98)b
B
E. coli, mpn/g
40,504 (3,187)
SalmonellaC
+++
N/A
D
a
b
Total solids losses, %
Volatile solids losses, %
N Losses, %
N/A
N/A
62.1 (1.97)
63.2 (5.99)
N/A
N/A
54.8 (0.84)
55.2 (3.00)
a,b
Means within a row with different superscripts are significantly different P < 0.05).
A
B
Values in parentheses are standard deviations.
mpn/g = Most probably number per gram of dry weight of sample.
C
+
= presence of Salmonella in one sample; − = absence in one sample (number of samples = 3).
D
N/A = not applicable.
to an active standard level. A 120-g sample of
tween 50 and 65% [20]. In this experiment, be-
cause of the presence of eggshells that do not
absorb water, MC of both treatments was below
45% during the composting process (Figure 1).
In some cases, further addition of water gener-
ated leachate. Although moisture remained at
this low level, there was no limitation on micro-
bial activity as could be observed from the tem-
perature profile (Figure 1). Average MC of the
two treatments throughout the experiment was
not significantly different and therefore should
not have had any effect on the progress of the
composting process.
the incubated material was placed in an aerated
respirometric flask at constant temperature in a
water bath (37°C) for 1 h. The aeration source
was removed, and oxygen concentration inside
the flask was monitored every 5 min for 1 h.
The change in oxygen concentration in the flask
was used to calculate a consumption rate in milli-
gramsoxygen/gramsvolatile solids per h. This rate of
oxygen consumption under standard conditions
of particle size, moisture, temperature, aeration,
and incubation is dependent only on the amount
of substrate availability. Greater substrate avail-
ability results in higher oxygen demand, indicat-
ing that the sample is biologically unstable. Or-
ganic compost with a SI less than 0.5 mg/g per
h is considered stable and 1.0 to 1.5 mg/g per
h is moderately stable. Unstable composts typi-
cally exhibit SI greater than 2.0 mg/g per h [16].
Fecal coliform counts were measured using
the IDEXX Quanti-Tray system [17] following
the manufacturer’s recommended procedure and
Method 9223B [18], and Salmonella enteritidis
was analyzed using Method 998.09 described
by AOAC [19].
The two treatments maintained similar tem-
perature profiles, until after the third mixing (34
d). Initially, rapid increases in temperatures to
6
5°C were observed followed by reductions in
temperature around the 7th d, possibly due to
oxygen limitations, which remained below 2%
for the first 30 d. After each event of homogeniz-
ing the compost, there was a slight increase in
oxygen concentration and a significant increase
in temperature (Figures 1 and 2). Temperatures
were maintained around 65°C for 30 d in both
treatments and for 60 d in the treatment with
PL. This high temperature for long durations is
required for elimination of pathogens.
RESULTS AND DISCUSSION
The SI measured at each mixing event
showed that, initially, the SI was higher for the
treatment without PL (Figure 2). Average SI
throughout the composting process remained be-
Process Parameters
For best results, it is recommended that the
MC of materials being composted remain be-

DAS ET AL.: HATCHERY WASTE COMPOSTING
287
FIGURE 3. The changes in volatile solids (above) and total nitrogen (below) contents in hatchery waste mixes
during composting. PL = poultry litter. Arrows indicate days when compost was homogenized and water was added.
low 0.60 mg/g per h for the treatment without
PL and at or below 0.20 mg/g per h for the
treatment with PL. When composting poultry
manure amended with municipal solid waste,
average SI is about 2.0 mg/g per h and decreases
to about 0.50 mg/g per h by the end of the
composting process [15]. An SI value of approx-
imately 0.10 mg/g per h reached after 70 d of
composting indicates that a highly stable com-
posted product can be achieved in 10 wk of
composting in a bin system as used in this re-
search.
Pathogen Reduction
The presence of E. coli and Salmonella was
considerable in both of the initial treatment
groups (Table 2). E. coli in the initial samples
was greater than 40,000 mpn/g at the start of
composting in both treatments. By the comple-
tion of composting, a high percentage (99.9%)

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of E. coli was eliminated, with the reduction
possibly due to a combination of the high tem-
peratures that were observed and the microor-
ganisms degrading organic matter competing for
food sources with the pathogens. Temperatures
greater than 55°C for several days during com-
posting can result in significant reduction in the
counts of E. coli and other pathogens [21].
Although Salmonella was present in all three
initial replicates of each treatment, after com-
posting it was not found in the treatment con-
taining PL but was present in two of the three
replicates not containing PL. The PL treatment
maintained a temperature greater than 60°C for
more than 60 d and greater than 45°C for the
rest of the composting period, whereas a temper-
ature of 60°C was only maintained for 30 d or
less in the treatment without PL. Apparently
this shorter period of high temperature was not
sufficient to completely inactivate the Salmo-
nella in this treatment. It has been reported that
when composting municipal solid wastes Salmo-
nella is absent after 27 d of composting while
temperature is maintained between 54 and 66°C;
however, organisms reappeared at 57 d when
temperature declined to 28.3°C, probably due to
the absence of competing microorganisms and
the abundance of Salmonella in the substrate
[22].
Degradation during Composting
The quantity of VS (volatile solids) in hatch-
ery waste was the lowest among all the ingredi-
ents used in the compost mixture (Table 1).
Therefore, the majority of degradable volatiles
in the mixes could be attributed to the amend-
ments (sawdust, PL, and yard trimmings). The
treatment with PL contained more VS (Table 2)
because of the higher quantity of these solids in
poultry litter (83.6%) and because this treatment
contained a higher ratio of sawdust to hatchery
waste (8:1) than the treatment without PL (6:1).
VS contents were reduced from 59.9 and 46.5%
to 49.0 and 35.3% within 16 d for the treatments
containing PL and no PL, respectively (Figure
3). A second reduction in VS content was ob-
served after the fifth mixing (71 d), when VS
content was reduced to 34.2 and 25.4% for the
PL and no PL treatments, respectively. This sec-
ond phase of VS content reduction is probably
due to microbial population successions and the
presence of secondary organic substrates that
TABLE 3. Nutrient and metal concentrations in final compost product of hatchery wasteA,B
Element
Treatment with PL
Treatment without PL
Major plant nutrients (g/kg)
B
P
K
6.6 (0.5)
1.8 (0.4)
1.4 (0.3)
180.0 (29.4)
2.6 (0.4)
0.1 (0.0)
1.3 (0.3)
0.9 (0.3)
0.3 (0.2)
1.3 (0.2)
10.8 (0.4)
155.6 (0.2)
4.2 (0.4)
0.4 (0.0)
2.2 (0.3)
2.6 (0.3)
1.5 (0.4)
3.6 (0.1)
Ca
Mg
Mn
Fe
Al
S
Na
Regulated heavy metals (mg/kg)
As
Cd
Cu
Pb
Hg
Mo
Ni
18.4 (1.6)
0.0 (0.0)
5.7 (2.7)
0.1 (0.0)
60.0 (14.7)
7.2 (6.3)
BDL
0.3 (0.2)
5.9 (5.8)
0.2 (0.2)
13.5 (3.7)
232.0 (26.0)
5.2 (0.6)
C
BDL
2.2 (0.2)
6.3 (1.3)
0.8 (0.1)
Se
Zn
158.0 (19.2)
A
Hatchery waste compost with or without poultry litter (PL) as amendment.
Values in parenthesis are standard deviations.
B
C
BDL = Below detection limit.

DAS ET AL.: HATCHERY WASTE COMPOSTING
289
become more available for biodegradation. Total
VS loss over the composting process was greater
and 0.63%, respectively, corresponding to an
average N losses of 63.2 and 55.2%.
(
(
P = 0.004) for the treatment containing PL
Compost Product Quality
62.1%) than the treatment without PL (54.8%).
Similarly, the total loss in dry mass was greater
Hatchery waste compost contained substan-
tial concentrations of plant essential nutrients
(
(
(
P = 0.004) for the treatment containing PL
33.5%) than for the treatment without PL
17.3%).
(Table 3). Both final products contained high
concentrations of Ca due to the presence of egg-
shells (15.56 and 18.00% for treatment with PL
and without PL, respectively). The PL hatchery
waste compost contained higher quantities (two
to eight times) of most nutrients (except Ca)
than the compost without PL. The PL hatchery
waste product had nutritional values equivalent
or in some cases exceeding other compost prod-
ucts such as animal manure and biosolids based
compost [23, 24]. Also, hatchery waste compost
contained lower levels of heavy metals than al-
lowed by regulators for biosolids for land appli-
cation [25], therefore making hatchery waste
compost suitable for use as a soil amendment
at generous application rates.
The presence of PL provided higher (P =
0
.046) initial N content in this treatment (2.7%)
than the treatment without PL (1.84%); however,
the initial C:N ratios were comparable (Table
). N content was reduced throughout the com-
2
posting process for both treatments (Figure 3).
The N content was reduced gradually over the
experimental time for the treatment without PL,
whereas a rapid decrease was observed in a short
period (first 16 d) for the treatment with PL.
This more rapid loss can be attributed to the
mineralization of organic N and its loss into the
environment as ammonia. The final N content
in the treatments with and without PL were 0.95
CONCLUSIONS AND APPLICATIONS
This paper reports results from pilot-scale research in which hatchery wastes were composted with
poultry litter (PL) as an amendment compared to a control with no poultry litter. The important
conclusions derived from this work are as follows
1. Treatment of hatchery waste by composting with sawdust, yard trimmings, and PL produced a
stable compost product that is rich in plant nutrients.
2
3
. Stability was achieved in 10 wk by using a bin composting system.
. Oxygen limitations were observed throughout the initial 35 d of composting, which could have
been a result of the type of bin used in this research or a lack of sufficient porosity in the
matrix. Future work could use a mix with greater porosity or use forced aeration to prevent
extremely low oxygen levels during composting.
4
5
6
7
. Use of PL as an amendment resulted in greater losses of organic and dry matter and more
efficient elimination of Salmonella.
. Both treatments were successful in reducing E. coli counts by more than 99.99%, suggesting
that the presence of poultry litter did not provide any additional benefits in E. coli reduction.
. Composting can effectively be used to reduce and eliminate pathogens in hatchery waste through
heat inactivation and substrate consumptions by competing microorganisms.
. Hatchery waste can be diverted from landfills through composting to produce a value-added
product that is agronomically attractive and can be used as a soil amendment and source of
plant nutrients.
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1
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