CEN/TR 13097:2010

SLOVENSKI STANDARD
01-julij-2010
1DGRPHãþD
SIST CR 13097:2001
Karakterizacija blata - Dobra praksa za uporabo blata v kmetijstvu
Characterization of sludges - Good practice for sludge utilisation in agriculture
Charakterisierung von Schlämmen - Leitfaden für die Verfahrensweise bei der
Verwendung von Schlämmen in der Landwirtschaft
Caractérisation des boues - Bonne pratique pour la valorisation des boues en agriculture
Ta slovenski standard je istoveten z: CEN/TR 13097:2010
ICS:
13.030.20 7HNRþLRGSDGNL%ODWR Liquid wastes. Sludge
65.080 Gnojila Fertilizers
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 13097
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
June 2010
ICS 13.030.20 Supersedes CR 13097:2001
English Version
Characterization of sludges - Good practice for sludge utilisation
in agriculture
Caractérisation des boues - Bonne pratique pour la Charakterisierung von Schlämmen - Leitfaden für die
valorisation des boues en agriculture Verfahrensweise bei der Verwendung von Schlämmen in
der Landwirtschaft
This Technical Report was approved by CEN on 9 February 2010. It has been drawn up by the Technical Committee CEN/TC 308.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 13097:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .3
1 Scope .4
2 Normative references .4
3 Terms and definitions .5
4 Requirements .5
4.1 General .5
4.2 Preliminary procedures .6
4.2.1 General .6
4.2.2 National regulations .6
4.2.3 Voluntary agreements .6
4.2.4 Quality assurance .6
4.2.5 Strategic evaluation .7
4.2.6 Sludge quality .8
4.2.7 Sludge type .9
4.2.8 Design of the sludge utilisation programme .9
4.3 Quality control (including environmental and agronomic data) .9
4.3.1 Process control .9
4.3.2 Sludge sampling and analysis .9
4.3.3 Maintenance of sludge quality . 11
4.3.4 Soil sampling and analysis . 11
4.4 Assuring hygiene when sludges are used in agriculture . 12
4.4.1 General . 12
4.4.2 Hygiene control by application and relating sludge type to land use . 13
4.5 Operation . 13
4.5.1 General . 13
4.5.2 Communication strategy and public relations . 13
4.5.3 Operational planning . 14
4.5.4 Storage . 14
4.5.5 Delivery . 15
4.5.6 Application techniques . 15
4.5.7 Nutrient management, application rate and times . 17
4.5.8 Data recording . 18
4.5.9 Additional guidance to customers . 18
4.6 Promotion of agricultural use . 18
4.6.1 General . 18
4.6.2 Market development . 19
4.6.3 Agronomic support. 19
4.6.4 Marketing and selling procedures . 19
4.7 Support procedures. 20
4.7.1 Quality assurance . 20
4.7.2 Continuous improvement . 20
4.7.3 Data and record keeping . 20
Annex A (informative) Guides of good practice for use and disposal of sludges. 22
Bibliography . 23

Foreword
This document (CEN/TR 13097:2010) has been prepared by Technical Committee CEN/TC 308
“Characterisation of sludges”, the secretariat of which is held by AFNOR.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes CR 13097:2001.
This document gives recommendations for good practice but existing national regulations remain in force.

1 Scope
This Technical Report describes good practice for the use of sludges in agriculture (where national regulations
permit). It is applicable to all of the sludges described in the scope of CEN/TC 308 (and any of the forms in
which they may be presented - liquid, dewatered, dried, composted, etc.) i.e. sludges from:
 storm water handling;
 night soil;
 urban wastewater collecting systems;
 urban wastewater treatment plants;
 treating industrial wastewater similar to urban wastewater (as defined in Directive 91/271/EC [1]);
 water supply treatment plants;
 but excluding hazardous sludges from industry.
Such sludges may be used on land as a source of plant nutrients, and/or soil improver, and/or alkaline
amendment for crop production. Despite differences in the statutory controls between sewage sludge and
other sludges, the use of all types of sludge should follow good practice to maximise benefits for the crops or
soils, to minimise potential risks of environmental contamination and adverse impacts on plant, animal and
human health, and to ensure sustainability, energy efficiency and cost-effectiveness.
Sludge producers should be aware that if a sludge is used as a fertilising or alkaline amendment, national or
EU fertiliser or liming regulations may apply.
The document assumes that an evaluation of sludge utilisation has already been made, and a decision was
taken that use of sludge within a land spreading policy is the best option.
For evaluation and decisions for use of sludges, other documents have been developed (see CR 13714,
CR 13846).
Many countries and/or local administrations have regulations and/or standards and/or codes of practice
applicable to the use of some of the types of sludge that are within the scope of this Technical Report,
however it cannot, and does not, attempt to summarise or take account of these regulations, etc. because of
their very wide range. It is thus essential that this Technical Report is read in the context of the conditions that
prevail locally.
NOTE Adoption in France in 2002 of a standard for standardized composts containing substances from wastewater
treatment NF U44-095: Organic soil improvers – Composts containing substances useful for agriculture, stemming from
water treatment.
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.
EN 1085:2007, Wastewater treatment — Vocabulary
EN 12832:1999, Characterization of sludges — Utilisation and disposal of sludges — Vocabulary
CEN/TR 15809, Characterization of sludges — Hygienic aspects — Treatments
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 1085:2007, EN 12832:1999 and the
following apply.
3.1
potentially toxic substances (PTS)
substances which, when present in excess and in forms that are available to the subject in question, can be
toxic
(CEN/TR 15584)
3.2
BPEO
best practicable environmental option
4 Requirements
4.1 General
The purpose of this Technical Report is to assist sludge utilisation operations to:
a) achieve compliance with 86/278/EEC and other environmental legislation or codes of good practice which
are relevant to the type and use of sludge or to the location of operations;
b) gain and maintain the confidence of users, authorities responsible for monitoring regulatory compliance,
food purchasing and/or processing companies and third parties which (amongst others) include members
of the public (particularly those local to where the sludge is applied);
c) make maximum use of the valuable constituents in the sludge;
d) have a long term sustainable solution with minimum cost and maximum benefit to the environment
consistent with the above.
Considerations of treatment, source control of pollutants and preparation of sludges are discussed in
CEN/TR 13714, CEN/TR 15473 and CEN/TR 15809.
The widely recognised waste management hierarchy recommends, in general, the utilisation of sludge as
preferable to disposal options such as landfill. Where agricultural land is available and conveniently
accessible, this is usually the best practicable environmental option.
Sludges usually contain nutrients, organic matter and trace elements, which are beneficial to the growth of
crops (including energy crops and grass) and to the fertility, structure and/or texture of soils. They are
therefore valued by farmers. Sludges may contain contaminants, and/or pathogens, and may be odorous.
Consequently, the whole process (from source control of potential pollutants, through sludge treatment, to
sludge application and the way the land is farmed) should be controlled to avoid adverse impacts on the
environment, or on plant, animal and human health. Such safe controlled use of sludge on land can be
considered a component of sustainable development.
Many European countries have developed guidelines and regulations for the safe use of sewage sludge.
These have been placed on a common statutory basis in the European Union through the implementation of
the EU Directive 86/278/EEC which requires certain limit values for PTSs in soil and sludge. Other EU
legislation encourages the utilisation of suitable industrial sludges on land provided measures are taken to
avoid endangering human health or harming the environment (91/156/EEC [3] amending Directive
75/442/EEC on waste). However, unlike the situation for sewage sludge, there is little detailed information
available and there is less legislative control for these other sludges. In the past the emphasis has been on
preventing chemical pollution, but whilst this is still essential, the modern agenda also includes hygiene
(CEN/TR 15809), and the need to demonstrate safety through quality assurance and independent validation.
European legislation has effectively eliminated many hazardous substances from products and the
environment. The REACH programme [4] continues the control on hazardous substances at source.
In order to establish and maintain cost-effective, safe and sustainable operations using sludge in agriculture,
certain procedures should be established for effective operational management, to meet legal requirements
and to address the concerns of stakeholders.
This document has been constructed in an order that attempts to reflect the logical steps of a successful
(which also means sustainable) sludge utilisation operation. It starts with the initial steps in designing an
operation, and then considers the quality control, design, etc., before moving on to the day-to-day operations.
Although marketing (finding outlets) and support are also continuing activities they are treated in separate
sections because they are general and not particular to each individual outlet. Despite this linear structure,
continuous improvement is recognised as an important component, which therefore implies the cycle of
design, operate, review, refine, operate, review, etc.
4.2 Preliminary procedures
4.2.1 General
This section discusses the more significant procedures and considerations for setting up a new programme to
use sludge in agriculture or modifying an existing one. These would include understanding the relevant
regulations within which the sludge is used, the quantity of the sludge, the quality of the sludge, whether there
are programmes for ensuring sludge quality, and whether there would be demand for the sludge; including
whether there are competing materials, e.g. animal manure or compost and biogas residues of other
materials.
4.2.2 National regulations
In the case of sewage sludge, national regulations set quality standards for the receiving soil and may set
standards for the sludge. The specific values and combinations of control mechanisms vary between
countries, and a combination of sludge, waste management, water and general agricultural and environmental
regulations may apply. Few countries have comprehensive regulations to control all sludges that may have
similar environmental impacts. Those using sludges should make themselves aware of the regulations that
apply in the areas where they are working. CEN/TC 308 has compared and discussed different sludge
treatment operating parameters in CR 13846.
4.2.3 Voluntary agreements
In some countries, some sludge producers have gone beyond national regulations by voluntarily entering
agreements with interested parties (such as food retailers and processors, farmers and landowners). These
agreements have addressed the question of perception and increased the acceptance of using sludge in
agriculture. Any applications of sludge should be consistent with these agreements.
4.2.4 Quality assurance
It is recommended that there should be a quality assurance system for the whole process from source control
of potential pollutants, through sludge treatment and spreading, and finally to how the land is farmed. To prove
transparency and ensure the confidence of stakeholders, it is desirable that this is validated by an
independent audit.
The principal criteria should include:
a) sludge quality, particularly:
 control of potential pollutants from point sources;
 sampling and analysis strategy to monitor sludge quality (PTSs, pathogens and its fermentability (i.e.
potential to produce bad odours);
 treatment of sludge.
b) soil quality, particularly:
 a soil sampling strategy to monitor soil quality for the concentrations of specified PTSs, often in
relation to certain soil conditions, such as pH, soil type and content of organic matter and/or cation
exchange capacity, in order that limit values are not exceeded.
c) sludge application rate, particularly:
 average quantity of PTSs that can be applied to the land and over what period, usually in terms of
kg PTS/ha⋅y (or multiple of years), or mg PTS/kg nutrients;
 amount of sludge dry solids that can be applied per year or multiple of years;
 quantity of nutrients which can be applied in accordance with the content of soil and the need of
crops grown;
 timing of and method of applying the sludge and after-use of the land and crops; these are generally
designed to protect animals and food consumers from pathogen transfer, and/or conserve plant
nutrients, and/or reduce the risk of run-off.
It is a general legal requirement for sewage sludge that appropriate records are maintained which in addition
to the above criteria, should include information on sources and quantities applied and the location of the
receiving land. However most countries do not yet require the same rigour for other sludges, even though they
may have environmental effects similar to sewage sludge.
4.2.5 Strategic evaluation
In order to launch a sludge utilisation programme, a strategic exercise should be undertaken in order to
evaluate its probable viability and sustainability within the area of land that is being considered for sludge
recycling. This is particularly important where there has been no previous experience of using sludge, or when
introducing a new sludge product.
A two phased approach should be adopted:
a) firstly, a comprehensive evaluation of the whole sludge strategy should be undertaken, employing BPEO
methodologies. This would test the security, practicability environmental sustainability and economic
viability of a proposed operation in an objective manner. Such evaluations would cover a wide range of
factors that would probably include many of the following, which is neither exclusive nor in an order of
priority:
 area of land that might be available;
 possibilities for temporary storage, if necessary;
 farming practices and other relevant land use information;
 use of alkaline amendment and fertilisers;
 what other "competitor" materials are available and their quality and quantity;
 national and local legislation and controls that would affect the operation of the proposed sludge use
programme;
 reaction of farmers' organisations, the food industry and other stakeholders;
 management and organisation of the sludge production plant;
 sensitive zones (surface and ground water protection, housing, etc.);
 soil (type, quality, trafficability, nutrient status and pollutant content);
 sludge type, sludge quality, sludge quantity;
 climate, e.g. is there a rainy season when trafficability is low or a long frozen period when sludge
application can be prohibited;
 topography, roads, bridges, etc. to evaluate access;
 consultation with a wide range of organisations to check the environmental and practical
sustainability of the proposed sludge use programme;
 type of sludge that might be produced (e.g. liquid, dewatered, dried, composted, digested, limed,
etc.) by varying the production or treatment process, that is the most appropriate for a sustainable
sludge use programme, bearing in mind the whole life cost of the alternatives;
 size, structure and location of storage facilities;
 some countries may require public consultation on the intention to start a sludge utilisation
programme that involves advertising the intention and consulting with municipal administrations.
b) secondly, as an extension to a BPEO study, or as a separate exercise where sludge use programmes
have been initiated or are ongoing, it is crucial to understand the potential customer base, its business
needs, and how the proposed sludge use programme can satisfy these needs. This should be done using
the whole marketing mix to test whether there is actually a market for the sludge.
4.2.6 Sludge quality
The preliminary stage should develop a methodology for controlling, monitoring, improving and maintaining
sludge quality. The quality of sludge is crucial for its safe, beneficial and sustainable use, and for its suitability
to be brought to the market". This invariably requires a rigorous source-control programme. A range of
chemical, physical and microbiological quality criteria is important for compliance with legislation, for providing
agronomic value, and for it to be aesthetically acceptable.
In the case of sewage sludge it is important to ascertain at the preliminary stage whether there is enabling
legislation and an effective system for controlling discharges from factories to the sewerage system or
whether such control at source can be implemented. A wide range of contaminants can be found in some
sewage sludges due to discharges from industries, dwellings and surface drainage into sewers. Soil with an
active microflora is capable of breaking down many organic compounds found in sludges. Experience has
shown that, when sewage sludge has been used in compliance with the current controls over loading rate and
use established in 86/278/EEC, no detrimental impact has been detected. For other sludges comparable
systems should be designed to prevent excessive contamination from entering the sludges. Animal manures,
food processing and abattoir sludges, and industrial residuals (e.g. paper, etc.) can contain significant
concentrations of PTSs (and/or pathogens). The use of these materials on land should be taken into
consideration when sewage sludge is applied in order to avoid over-application of PTSs and nutrients. It is
important to recognise that agricultural land receives inputs of potentially harmful compounds from other
sources, such as atmospheric deposition, traffic emissions, inorganic fertilisers and crop protection chemicals.
In regard to the microbiological qualities, it is not practicable to undertake frequent monitoring for specific
pathogenic organisms because levels present can be extremely low and difficult to detect. As has been
adopted for drinking water microbiology, some monitoring of suitable indicator organisms such as E. coli may
be a preferable way of verifying that the overall processes of treatment and use meets specified hygienic
requirements (see also CEN/TR 15809). Information about principles to be followed in different sludge
treatment processes to reach specified hygienic requirements is given in CEN/TR 15809.
Some waterworks sludges may be beneficially applied to land to use their contents of organic matter and/or
alkaline amendment, or even to modify soil texture. However there are some waterworks sludges that have
negligible soil enhancement value. Waterworks sludges generally have a low content of N, P or K. These
sludges result from the treatment of surface or ground waters. Their contents of PTSs and other contaminants
are generally low. They are useful when soil improvement by the addition of organic matter or textural
modification (e.g. adding silt to excessively drained coarse textured soils) or soil pH adjustment (by liming) are
required but major plant nutrients are not needed.
4.2.7 Sludge type
Dewatering, drying, lime treatment, nutrient addition, composting and other processes may be beneficial to
improve the properties of the sludge for its use in agriculture. Physically the material should be capable of
easy storage and application. It should be treated to minimise the possibility of odour emission so that the
public (particularly those local to where the sludge is applied) and the farmers’ requirements are addressed.
Sustainability may be enhanced by use of the appropriate treatment and application techniques.
4.2.8 Design of the sludge utilisation programme
Before commencing a sludge utilisation programme, the overall design, infrastructure, procedures and
resourcing should be considered. Many of the components are discussed later in this document. They include
the capacity, design and siting of storage facilities, with their relevant equipment (stirring, access, recovery,
etc.), vehicles and their servicing, spreading equipment, labour, computer hardware and software. Locally
prevailing regulations shall be complied with.
4.3 Quality control (including environmental and agronomic data)
4.3.1 Process control
Rigorous control at certain critical control points in the production and recycling process, backed up by the
verification of independent audit contributes to ensuring the safety of sludge recycling and the confidence of
important stakeholders. The critical control points and their critical values need to be identified and evaluated
for each particular sludge processing and recycling example.
4.3.2 Sludge sampling and analysis
Sludges and sludge products should be sampled and analysed in order to:
 provide reliable information to customers;
 satisfy regulatory requirements;
 confirm that process controls are effective.
The frequency of sludge sampling and analysis should be appropriate to the size of the production plant and
any anticipated fluctuation in quality. Plants producing large quantities of sludge, and plants where there is a
variety of inputs and where varying quality is expected should be sampled more frequently. In general, sludge
should be analysed at least every six months, based on composite samples derived from representative sub-
samples.
The method of sampling sludge should be evaluated carefully to ensure that the samples are representative of
the quality of the sludge that is actually applied to land. This is particularly important for accurately measuring
dry solids content, and the sludge should be well mixed prior to sampling.
The quality of certain industrial residuals for land spreading may vary substantially from batch to batch which
should be taken into account in the sampling regime in order to ensure that representative samples are
obtained.
The parameters that should be measured routinely in sewage sludge for compliance with regulations and to
provide agronomic advice are:
 dry matter;
 loss on ignition (which is used as an approximation of organic matter);
 pH;
 total nitrogen;
 total phosphorus;
 zinc;
 copper;
 nickel;
 cadmium;
 lead;
 mercury;
 chromium.
Some countries may require additional determinants to be analysed. In some circumstances, or for some
sludges, analysis to comply with national or EU fertiliser or liming regulations may be required in some
countries. It may be desirable to monitor the concentrations of other constituents, where these are known to
occur in significant concentrations or would be useful in evaluating agronomic quality. Some examples of
these additional parameters are:
 ammoniacal nitrogen;
 available phosphorus;
 potassium;
 magnesium;
 calcium;
 sulphur;
 sodium;
 manganese;
 molybdenum;
 boron;
 selenium;
 arsenic;
 fluoride;
 cobalt;
 neutralising value;
 persistent organic pollutants.
Other sludges should at least be analysed for nutrients and organic matter to determine their agricultural
benefit. Whilst the risks have been well characterised for sewage sludges, some other sludges may be less
well understood, and the process by which they are produced and the possible contaminants etc. that can be
in the sludge should be assessed to decide on the need for monitoring other parameters.
Standard methods of sampling and analysis should be followed where they are available. A permanent record
of the information should be maintained, and copies should be provided to the recipients of the sludge.
4.3.3 Maintenance of sludge quality
Litter in sludge that is spread on the land should be avoided by effective screening during the treatment
process.
Operational parameters (e.g. digester temperature) should be measured and recorded to ensure that
appropriate quality and also traceability is maintained. Aspects of sludge treatment to ensure that hygiene is
dealt with are in 4.4.2.
Personnel involved with sludge utilisation programmes should liaise with the sludge producer (and, in the case
of sewage sludge, those involved in industrial effluent control) regarding the maintenance and/or improvement
of sludge quality for:
 sludge stability and odour;
 consistency of analyses with respect to constituents of agronomic benefit;
 content of PTSs.
4.3.4 Soil sampling and analysis
Many countries require that soils are sampled prior to sewage sludge being applied for the first time to
establish baseline concentrations of PTS's (some require that nutrients are also measured), and then at
specified frequencies to monitor soil concentrations following repeated applications of sludge. Others have
decided from their soil mapping and inventory that this is unnecessary (at least in certain areas) because the
concentrations in soil are already known to be very low, and/or the PTSs applied do not exceed an amount
similar to that in manure.
When sludge is applied to land repeatedly over many years, PTSs can accumulate in the soil, and if this were
permitted to continue unchecked, concentrations could possibly be reached that could cause adverse effects
to soils, plants, animals or humans eating food produced on sludge treated soils. In the case of sewage
sludge, regulatory limit values have been set for some PTSs (heavy metals) in Directive 86/278/EEC and they
shall be complied with and confirmed by soil sampling and analysis.
The method of soil sampling should comply with that described by ISO/TC 190 on Soil Quality.
Parameters which require monitoring to comply with 86/278/EEC are:
 pH;
 zinc;
 copper;
 nickel;
 cadmium;
 lead;
 mercury;
 chromium.
Individual countries, regions or areas may require additional parameters.
It may be advisable occasionally to monitor other PTSs, such as molybdenum, arsenic, selenium and fluoride,
particularly in areas that may have naturally high background soil concentrations and where the land is used
for grazing or forage production.
Soil analyses ensure compliance with statutory limit concentrations, but because each application of sludge
can add only very small quantities of PTSs, monitoring over an extended period is advisable and is addressed
by states’ regulations. Frequent sampling may be advisable depending on the concentrations of PTSs in the
sludge and how close soil concentrations are to their respective limit values, or how close they are predicted
to be based on the cumulative loading to date. Some countries, regions or areas may specify a frequency for
soil sampling.
Soil analyses should be compared with the theoretical calculation of soil concentrations, based on sludge
quality and rate of sludge application. This information should be used (from time to time) to readjust the
model of how many applications of sludge the land can be permitted to receive before it approaches the limit
value of the most limiting PTE. It may also be used to allow calculations of steady state levels of PTSs to
avoid further accumulation in the long run.
4.4 Assuring hygiene when sludges are used in agriculture
4.4.1 General
Hygienic aspects of sludge treatment are covered in detail by CEN/TR 15809.
When sludges are used in agriculture for their beneficial constituents and effects, consideration should also be
given to the overall hygiene of the process. As has been stated before, Europe has a model for protecting
hygiene in its regulations for the use of sewage sludge in agriculture. This established a dual barrier approach.
One barrier is provided by sludge treatment and another by specifying intervals between sludge application
and crop harvest or grazing or by prohibition of certain crops. Incorporating sludge into soil can also provide a
barrier.
The health of people involved in treating and using sludge should be protected by educating them in the need
for relevant hygiene precautions including personal protective equipment (overalls, boots, gloves, etc.).
4.4.2 Hygiene control by application and relating sludge type to land use
Application techniques and timing of application are both barriers to the possible transfer of pathogens.
Incorporating sludge into soil may provide a barrier. Directive 86/278/EEC stipulates that grass or forage crops
should not be harvested or grazed until at least 3 weeks after land has been treated with sewage sludge. It
also states that fruit and vegetable crops that are normally in direct contact with the soil and normally eaten
raw should not be harvested for at least 10 months following treatment of the soil with sewage sludge. These
are minimum standards for members of the EU. Countries have set their own protocols for relating types of
sewage sludge to the ways that land may be safely farmed appropriate to their local climatic and farming
conditions which states some national regulations exemplary. It is usual to combine timing or prohibition of
application and quality control of the sludge with special land use practices. To protect people, animals and
plants from disease transmission, control measures have to be operated correctly. There have been no
proven cases of disease transmission as long as these control measures have been operated correctly. For
example, the newsletter from the French Institute of Sanitary Survey (IVS) have not reported sanitary risk
associated with spreading of sludges in agriculture in many years.
It is also very important that the information about the incidence of sludges spreading on farming, harvest
intervals, etc. are effectively communicated to the farmers whose land has been treated.
As CEN members may have set more stringent or more detailed standards for sewage sludge, it is strongly
recommended that where relevant these protocols are adopted for all sludges.
4.5 Operation
4.5.1 General
This section discusses the day-to-day operation of a sludge utilisation programme. It is useful to develop a
"beneficial use culture" amongst everybody involved with sludge utilisation as opposed to a "disposal culture".
Adopting a beneficial use culture means that people think about sludge as a material to be used (not
disposed) which in turn militates for environmental protection and against pollution.
4.5.2 Communication strategy and public relations
4.5.2.1 General
Communication is an important part of any successful sludge utilisation operation so that customers can make
best use of the beneficial constituents and avoid any adverse effects and to satisfy the requirements for
information by other people. This communication strategy is partly day-to-day and partly a more strategic
activity (see also 4.6).
4.5.2.2 Communication with farmer-customers
Farmers who are well informed about the benefits of sludge and receive the quality of service promised, are
more likely to be regular customers. Establishing "repeat business" should be a priority for operational security
and cost-effective operation. The provision of sound and objective agronomic advice should be an integral
part of efficient sludge use programmes and ensuring customers' satisfaction. To achieve this, marketing and
quality control staff involved in customer contact should be well trained in agronomy and/or specialist schemes
where they are available.
Before spreading, and within the framework of a forecast programme, local regulations may require the
sending of documentation to customers informing them on the agronomic quality of the sludge to be applied,
as well as the quantities to be made available for their application.
After the sludge has been applied, local regulations may require that information is sent to customers about
the sludge with which they have been supplied. The directive (86/278/EEC) requires sewage sludge
producers to regularly provide users with all the information referred to in Annex II A of this directive (i.e. the
sludge analysis).
4.5.2.3 Consultation with others
In some countries and locations, prior to the application of sludge to an area of land, consultation with various
organisations responsible for the environment, waste management, infrastructure, etc., and other interest
groups may be necessary or desirable. The necessity depends on the locality and is intended to ensure
compliance with any restrictions placed on the land, or transport routes to the land, and that there are no
conflicts with local inhabitants. Where it is found to be desirable, consultation should be part of routine
operations as and when needed.
The types of responsible organisations to be consulted depends on national and local conditions, and
legislation, and therefore varies between countries and possibly even between local areas or regions. The
following are examples of possible constituents of a consultation programme (written in no order of priority):
 groundwater and surface water are protected. The consultation should establish whether the proposed
land for sludge application lies within an exclusion zone or sensitive area, that would prevent or restrict
either the quantity or timing of sludge use;
 agricultural organisations, farmers' unions, etc.;
 sites of special scientific or environmental interest are protected. This could prevent or restrict sludge
applications;
 appropriate routes for sludge transport are selected, avoiding weight restricted bridges;
 built-up areas, narrow roads, etc., as necessary. Sludge transfer points are selected to avoid obstructing
the highway or creating a hazard;
 proposed method of delivery, storage and application of sludge does not conflict with local waste
management and environmental health plans and policies;
 there are no conflicts with neighbouring sludge recycling programmes;
 local authorities are kept informed of sludge spreading operations.
4.5.3 Operational planning
A method of planning the work is necessary to ensure that there is a balance between the rate of sludge
production and the demand created amongst customers. There should also be a balance between the
spreading resource, the time available for spreading, the quantity to be spread, and the storage facilities.
4.5.4 Storage
Storage of either liquid or dewatered sludges is required as a part of the sludge management process.
Storage is a strategic necessity because the availability of agricultural land for sludge use is not continuous
due to legislated restrictions of spreading periods, local cropping practices, adverse weather, etc. Where
storage forms part of the treatment process, adequate assurance (supported by monitoring) should be put in
place to ensure the required level of treatment is achieved. The individual countries, regions or localities may
have different regulations on storage.
Liquid sludge is generally stored in tanks or lagoons at the production plant, or may be stored in on-farm
lagoons, or at some other site. Stirring or some other form of homogenisation of sludges may be required.
Permission to construct a lagoon may be required from local regulatory authorities, and this generally requires
an impermeable liner to prevent escape of sludge liquors into the soil. Lagoons should be securely fenced and
should meet standards for health and safety. Liquid sludge can be temporarily stored in mobile transfer tanks,
to facilitate the transfer of sludge from road transport to field application equipment (and should not be
considered as storage). This generally does not require any specific permission for use as a storage
container. A device to warn against or prevent over-filling is desirable.
Dewatered sludge may be stored on treatment plants on prepared hard-standings and is also commonly
stored on farmland (on a short-term basis) prior to application.
When choosing/evaluating a site for storage of sludge, consideration should be given to the risk of possible
leaching to groundwaters and run-off to surface waters. Consideration should also be given to the existence of
field drains, slopes that might result in the stockpile slumping (down slope) or being flooded (if it is in a
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