ISO 28901:2011

INTERNATIONAL ISO
STANDARD 28901
First edition
2011-09-15
Soil quality — Guidance for burial of
animal carcasses to prevent epidemics
Qualité du sol — Lignes directrices pour l’enfouissement des carcasses
d’animaux pour éviter une épidémie
Reference number
ISO 28901:2011(E)
©
ISO 2011

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ISO 28901:2011(E)
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ISO 28901:2011(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Objectives and constraints . 2
5 Planning of burial programme . 3
5.1 Time of burial . 3
5.2 Consideration of diseases and kind of animal carcasses infected . 3
5.3 Selection of burial site . 4
6 Construction of burial pit . 9
6.1 Preparation of the site . 9
6.2 Excavation of the burial site .10
6.3 Placement of lining materials and discharge pipes .10
6.4 Placing of carcasses in the burial pit . 11
6.5 Coverage of burial pit after finalization of placement of carcasses . 11
7 Maintenance after burial .12
7.1 Safety measures .12
7.2 Odour treatment .12
7.3 Gas discharge .12
7.4 Leachate treatment .12
7.5 Surface regrading .12
8 Monitoring .12
9 Reuse of burial sites .12
10 Report and record keeping .13
Annex A (informative) Examples of national specifications regarding burial of animal carcasses .14
Annex B (informative) Diseases listed by the World Organisation for Animal Health (OIE) .22
Annex C (informative) Examples of the design of protection layers for perforated drainage pipes .26
Bibliography .27
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ISO 28901:2011(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International
Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 28901 was prepared by Technical Committee ISO/TC 190, Soil quality, Subcommittee SC 7, Soil and
site assessment.
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ISO 28901:2011(E)
Introduction
The incidence of livestock epidemics such as bovine spongiform encephalopathy (BSE), swine fever, foot and
mouth disease (FMD), Newcastle disease and avian influenza (AI) are becoming increasingly more frequent
and geographically widespread. These epidemics spread quickly across country borders due to rapid exchange
of people, animals and products between countries. Epidemics threaten the welfare of human beings through
secondary infection on other livestock, economic loss and public health. Preventing the spread of epidemics
to other areas where livestock are raised is the priority. However, when this fails and the epidemic has spread,
rapid and effective action should be taken to prevent the further spread of infection. Slaughter followed by
disposal of infected livestock is an essential means of preventing the spread of the epidemic.
Disposal methods for slaughtered livestock include: incineration, rendering, composting and burial. Burial is a
method that has long been used, as it is relatively economical and does not require specialized techniques or
equipment. However, it does have the potential to contaminate the receiving environment. Leachate from the
buried animal carcass can pollute the soil and the surrounding waters (groundwater and surface water), and
the gas caused by the decomposition of the carcass produces foul. Despite such drawbacks, burial continues
to be used widely, because it can limit the spread of an epidemic when massive amount of carcasses must
be disposed rapidly. The objectives of this International Standard are to curtail the spread of the disease, to
destroy the causative agents, and to dispose of the carcasses by burial.
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INTERNATIONAL STANDARD ISO 28901:2011(E)
Soil quality — Guidance for burial of animal carcasses to
prevent epidemics
1 Scope
This International Standard provides guidance on environment-friendly burial methods of animal carcasses to prevent
epidemics, to curtail the spread of the disease, to destroy the causative agents, and to dispose of the carcasses.
This International Standard does not apply to the burial of animal carcasses resulting from natural death
or by accident.
Other methods of disposal are outside the scope of this International Standard.
NOTE In some countries, infected animals or parts of animals cannot be buried on farms due to legislation but are
subject to handling by licensed commercial landfills or incinerations.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced document
(including any amendments) applies.
ISO 10390, Soil quality — Determination of pH
ISO 10694, Soil quality — Determination of organic and total carbon after dry combustion (elementary analysis)
ISO 11260, Soil quality — Determination of effective cation exchange capacity and base saturation level using
barium chloride solution
ISO 11272, Soil quality — Determination of dry bulk density
ISO 11277, Soil quality — Determination of particle size distribution in mineral soil material — Method by
sieving and sedimentation
ISO 13536, Soil quality — Determination of the potential cation exchange capacity and exchangeable cations
using barium chloride solution buffered at pH = 8,1
ISO 14688-2:2004, Geotechnical investigation and testing — Identification and classification of soil — Part 2:
Principles for a classification
ISO 25177, Soil quality — Field soil description
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
affected animal
animal which has been infectious or is at present infectious or is suspected of soon becoming infectious and
which is to be killed to prevent epidemics
3.2
animal carcass
dead body of an animal or parts thereof, or products of animal origin
NOTE Animal excreta are included in this definition.
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ISO 28901:2011(E)
3.3
burial
act of burying an animal carcass
3.4
discharge
action of releasing a substance such as a liquid or gas; a substance that is expelled from a defined area or location
3.5
disposal
collective noun for any operation to remove and discard waste
3.6
epidemic
large number of cases of a particular disease, usually infectious, occurring at the same time in a particular community
3.7
infectious waste
substance containing viable microorganisms or their toxins which is known or reliably believed to cause disease
in man or other living organisms
[EN 13965-1:2004]
3.8
leachate
liquid percolated through a soil and containing substances in solution or suspension
3.9
livestock
domesticated animals, usually kept on a farm
EXAMPLES Cattle, sheep, horses, pigs, chickens.
3.10
permeability
measure of the ease with which gases, liquids, or plant roots penetrate or pass through a bulk mass of soil
3.11
quicklime
liming material consisting mainly of calcium oxide or a mixture of calcium oxide and possibly magnesium oxide,
produced by the calcination of limestone, magnesian limestone or dolomitic limestone
[EN 12944-3:2001]
3.12
soil texture
relative proportions of the various particle size fractions (i.e. sand, silt, clay) in a soil according to a soil
classification system
3.13
wildlife animal
all non-domesticated animals
EXAMPLES Deer, wild boar, rodents.
4 Objectives and constraints
In the event of an epidemic in which an infectious disease either kills animals directly or causes them to be
killed, urgent action is required to
— curtail the spread of the disease,
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ISO 28901:2011(E)
— destroy the causative agents,
— rehabilitate those persons affected by the epidemic,
— return the land to profitable agriculture or other use,
— dispose of the carcasses, and
— dispose of excreta and other obnoxious material.
Four factors will constrain the work:
a) The need for urgency arises because there will be a multiplicity of pathways by which the causative agents
can be transmitted from live or dead animals within the area affected to animals in remote locations. The
causative agent can be spread by birds, other wildlife, or transported by wind or wind-blown dust, and
water. All of these mechanisms are difficult to control.
b) In an attempt to arrest some of these pathways, the site shall be quarantined, with movements of people
and other animals onsite and offsite being minimized, controlled and disinfected.
c) As a consequence, the work shall be constrained by what is in hand or can readily be obtained.
d) Further adaptation should be made to suit local ground conditions.
The number of animals involved shall also be considered.
NOTE For example, in one small outbreak in 2007, over 350 cattle were slaughtered on one day, and 800 pigs and
50 more cattle were slaughtered on the following day.
5 Planning of burial programme
5.1 Time of burial
Carcasses should be buried as soon as possible after their death. However, it should be noted that postmortem
livestock will gas up and increase volume by up to half. Therefore, if they are placed in a burial pit too soon and
covered over, the carcasses will subsequently rapidly degas, causing large voids to form and causing cracking
of cover material. Therefore, either the stock should not be covered immediately or the carcasses should be
pierced to prevent them gassing up.
Once buried, decomposition and degradation processes will intensify after 24 h to 72 h (depending on the
ambient temperature), which will pose additional threats to health and the environment.
Each country may have a specified time frame within which carcasses shall be buried.
5.2 Consideration of diseases and kind of animal carcasses infected
When livestock are sufficiently believed to be infected by an epidemic, owners of livestock in the area where
the epidemic has spread or may spread can be ordered to immediately eradicate the livestock. Livestock
eradication requirements can differ on a national scale, depending on the form of the epidemic. Diseases listed
by the World Organisation for Animal Health (OIE) are given in Annex B.
5.2.1 Consideration of volume of carcasses to be buried
It might be necessary to bury the following:
a) carcasses and parts thereof;
b) excreta, including: urine, dung, sweat, saliva, snot (nasal mucus), tears, earwax, milk, semen, “afterbirth”;
c) miscellaneous droppings, for example: hair, scurf, skin, blood;
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ISO 28901:2011(E)
d) infected straw, bedding mixed with dung, farmyard manure (if infected), etc.
Depending on the disease, some or perhaps all of these can transmit viable causative agents.
Burial volume is generally determined by the livestock’s species and size. If the burial volume is uncertain, it
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should be assumed that no more than 300 kg of carcass per 1 m will be permitted. Table 1 gives an indication
of average livestock weight.
Table 1 — Average livestock weight
Type Kind of animal Weight
kg
Beef cattle Cows and bulls 550
Feeder cattle 450
Replacement heifers 360
Calves 135
Dairy cattle Cows and bulls 600
Replacement heifers 450
Calves 135
Hog Boars or sows 150
Feeder pigs 100
Weanling pigs 16
Poultry Hens, cockerels, capons 1,8
Chicks, broilers 1,5
Hen turkeys, geese, ducks 8
Sheep 50
5.3 Selection of burial site
5.3.1 Deciding between onsite or offsite burial
In general, to avoid further spreading of the disease due to transport and handling, the infected livestock should
be buried at the site where they are found.
The principal advantages of burial over incineration are that burial tools are simple, and movements off the site
where infected animal carcasses occur are minimized.
When a suitable location for burial is not available on the farm, burial would have to be off the farm.
If the carcasses are buried on the farm, continuing maintenance and monitoring of the burial area are required
(in relation to an existing national specification, if available); see also Clause 8. This area should be taken out
of production.
NOTE The presence of the pit, even if landscaped, can reduce the value of the land.
5.3.2 Methods of burial
The following methods of burial are distinguished.
Simple burial: The carcasses are laid into a pit and soil is placed directly on top of them, perhaps with the
addition of some quicklime. In this method, earth-dwelling worms, insects, and bacteria have direct access
to the carcasses and assist in their disintegration. However, large volumes of obnoxious effluent are to be
expected, and the causative agents are likely to escape with the effluent, meaning that complete disposal of
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ISO 28901:2011(E)
the carcasses cannot be assured. Although this method has been used in the past, it should now be regarded
as unacceptable.
Aerobic burial: Although there appears to be a view that burial under carefully controlled aerobic conditions
(presumably without earth-dwelling worms, insects and bacteria) would ensure complete disintegration
and disposal of the carcasses, there appears to be little in the way of either scientific evidence or practical
experience to support this view.
Anaerobic burial: Recent practice seems to have been to envelop the carcasses in impermeable membranes
with a view to collecting the leachate. It seems probable that anaerobic conditions have developed in many
cases when such systems have been used but there is some doubt as to whether disintegration does occur
under anaerobic conditions.
5.3.3 Requirements for the burial site
Burial sites are limited to areas where human or livestock access can be controlled, and shall not be in the
vicinity of water sources, surface water and principal aquifers, main roads or residential areas. In addition,
other aspects, such as environmental designation, archaeological site history, existing underground services,
field drains, statutory and legal issues, need to be considered.
When the candidate site is in the vicinity of a principal aquifer, the site should only be used for burial if the
results of a trial pit and other investigations show that the site is safe.
The area selected should not be liable to flooding or become submerged during flood events.
Soft ground should be avoided in selecting sites.
Characteristics of the soil of the burial site, such as soil texture, permeability, slope, groundwater depth and its
topography, should be taken into consideration. Escarpments and sandy soils shall be avoided.
In selecting a site for burial, soil information obtained from trial pits can be useful. A trial pit is a shallow
excavation made to a depth of not greater than 5 m. The trial pit is to be used extensively at the surface for soil
sampling and detection of services prior to borehole excavation (see, for example, ISO 10381-4).
SAFETY PRECAUTIONS — An important safety point to note is that all pits below a depth of 1,2 m shall
be supported.
When preparing a trial pit, a log including such information as soil type, structure and groundwater levels
should be made.
The basic characteristic parameters given in Table 2 should be considered to evaluate the potential contamination
of soil and groundwater at the burial sites.
NOTE For more information regarding groundwater protection, ISO 15175 can be considered.
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ISO 28901:2011(E)
Table 2 — Substances and parameters to be considered in selecting sites for burial
Substance/parameter Method International Standard
Distance to water source — —
Distance to main roads — —
Distance to residential area — —
Depth of groundwater table — ISO 25177
Possibility of submergence in case of — —
flooding
Slope — ISO 25177
Soil texture Sieving, sedimentation ISO 11277
Permeability — —
Bulk density Direct measurement of undisturbed ISO 11272
soil samples estimation from soil
water-retention curves
pH pH-electrode ISO 10390
Organic carbon Dry combustion ISO 10694
Cation exchange capacity, BASCOMP, BaCl ISO 11260
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exchangeable cations
ISO 13536
Bearing capacity Cone penetration test —
Trial pit — ISO 14688-2:2004
5.3.4 Seasonal high groundwater level
Burial pits should be located on sites with soils having a seasonal high groundwater table not less than 1,5 m
below the bottom of the planned burial pit.
Some difficulty will be experienced in establishing the seasonal high groundwater level. Usually, this would
require observations to be taken from dip wells or the like, over the course of at least 1 year. However, usually
neither is the time available, nor is it advisable to drill holes from severely contaminated land down to the
water table. If this information is not already available, it might be possible to obtain a reasonable estimate
of seasonable high groundwater level from a desk study or from indirect observations. Otherwise, the best
possible estimate should be made and the possibility of error should be accepted.
Because a relatively deep excavation is being made without a thorough investigation, there is a small possibility
of breaking into an artesian aquifer. Should this happen, the excavation shall immediately be refilled with
compacted soil.
In the worst cases, it will be necessary to exhume the carcasses and start again.
5.3.5 Selection of the kind of pit
Usually onsite burial is preferable to offsite burial, given the potential of transmitting infection via transportation.
However, site-specific circumstances will usually dictate the best approach.
NOTE For example, in an area where a high density of farms has been affected, it might be more appropriate to have
one centralized and professionally managed disposal point, with carcasses transported to this point under appropriate
conditions. The advantage of this approach is that a more engineered design of the burial pit can be used, together with
more stringent monitoring of the disposal process. This approach reduces the number of smaller on-farm burial sites,
which for practical and financial reasons are invariably not well engineered or as closely monitored.
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ISO 28901:2011(E)
5.3.6 Design of the burial pit
There is no “one size fits all” design for burial pits. For centralized and professionally managed sites, a landfill-
like design (as given in Figure 1) may be appropriate. In contrast, on small and medium-sized individual farms,
it is unlikely that this approach can be used.
The design (and later construction) of the burial pit should be supervised by a competent civil engineer.
The depth of the pit should be such that the distance between the top of the carcass (once buried) and the
ground surface should be more than 2 m. The sides and the bottom of the pit should be covered with waterproof
material such as HDPE (high-density polyethylene) sheet.
Table 3 indicates the amount by which soil is likely to bulk up; i.e. increase in volume due to its lower compaction.
NOTE Loose soil is unlikely to settle to its original volume. The amount of settlement to be expected when the pit
is backfilled will depend, inter alia, on the nature of the soil, the thickness of the soil layer (self-loading), whether any
compaction is carried out, the moisture content and the amount of rainfall. Guidance on settlement processes can be
found in geotechnical guidance documents.
Table 3 — Examples of swelling behaviour of different materials
Material Swell
%
Clay 40
Loam 25
Sand 12
Gravel 12
Where no water courses are located nearby and no underlying aquifers are present, encapsulation with
impermeable materials or specialized capping materials may not be required. However, a site-specific
assessment of the appropriateness of the burial site would need to be made.
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ISO 28901:2011(E)
Dimensions in millimetres
Key
1 waterproof material: 6.3 Bringing in lining materials and discharge pipes
2 soil: 6.2 Execution of the excavation
3 perforated pipe: 6.3 Bringing in lining materials and discharge pipes
4 quicklime: 5.3.9 Use of lime, 6.2 Execution of the excavation
5 carcass: 6.4 Placing of carcasses in the burial pit
6 quicklime: 5.3.9 Use of lime, 6.5 Coverage of burial pit after finalization of placement of carcasses
7 filling: 6.5 Coverage of burial pit after finalization of placement of carcasses
8 bentonite: 6.5 Coverage of burial pit after finalization of placement of carcasses
9 soil: 6.5 Coverage of burial pit after finalization of placement of carcasses
10 leachate discharge pipe: 5.3.8 Effluent collection, 6.5 Coverage of burial pit after finalization of placement of
carcasses
11 leachate treatment system: 7.4 Leachate treatment
12 gas discharge pipe: 5.3.8 Installation of pipes for gas discharge, 6.5 Coverage of burial pit after finalization of
placement of carcasses
13 UV lamp: 5.3.8 Installation of pipes for gas discharge
14 drainage: 6.5 Coverage of burial pit after finalization of placement of carcasses
15 groundwater
Figure 1 — Schematic diagram of an animal carcass burial pit
5.3.7 Leachate collection
One or more perforated pipes shall be laid along the bottom of the pit to collect and remove leachate from the
carcasses, together with any other liquids entering the pit. Care shall be taken to ensure that no leakage can
occur at the point or points where such pipes leave the pit.
The top of the perforated pipe(s) should be covered with gravel to prevent their breakage and blockage by
leachate and carcass. Examples of the design of protection layers are given in Annex C.
Leachate should be removed and disposed of in a manner in keeping with current appropriate guidance within
each country.
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ISO 28901:2011(E)
5.3.8 Installation of pipes for gas discharge
Pipes should be installed to discharge gas produced from carcass decay. The gas discharge pipes should be
greater than 100 mm in diameter, perforated and U-shaped and face towards the ground surface in order to
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reduce stench and to prevent inflow of rainwater. At least 5 pipes should be installed every 90 m of the burial
pit. The pipe should be placed on a layer made from gravel to prevent blockage. For reasons of public health
and safety a suitable device for gas treatment should be installed at the end of each pipe. For example, a gas
sterilization filter (0,2 µm) or solar-cell-operated UV lamp can be used for this purpose.
5.3.9 Use of lime
The use of lime in an animal carcass burial site should be decided according to the national and local situation.
The principal reasons for adding lime are as follows:
a) to mop up excess water by conversion of calcium oxide to calcium hydroxide (i.e. slaked lime); this is
sometimes used on construction sites on which the surface soil has become too wet;
b) to alter the adsorption complex on clay with a view to modifying the behaviour of the clay;
c) to stabilize clayey soils by reaction with the clay;
d) to kill bacteria, probably by extracting water from them;
e) to convert foul-smelling gases to a less obnoxious form; for this to be successful, it is necessary to ensure
that the gases passed through the lime rather than escaping along preferential flow paths around it;
f) to convert foul effluent and leachate to less noxious forms;
g) to control the pH to promote bacterial and/or chemical disintegration of the carcasses;
h) to encourage earthworms; this would presumably apply only in cases of simple burial.
The disinfectant used to kill the causative agent for foot-and-mouth disease is acidic. On this basis, there is a
fear that the use of lime might help to preserve some causative agents. In addition, the high pH of the leachate
collected from the animal carcass burial site where lime is applied may cause problems in treating leachate.
5.3.10 Other aspects
When there are several burial pits at a site, the distance between the pits should be more than 6 m to enable
the movement of people and equipment.
6 Construction of burial pit
6.1 Preparation of the site
When the location of the burial pit has been decided, the following actions are desirable.
a) Exclude animals.
b) Collect debris and perhaps dung.
c) Disinfect the working area. This is intended to mi
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