Final Report
Industry Guidance: Dealing with Household
Food Waste at AD Facilities – Management
of Liners
A guide to assist AD operators in relation to food waste in liners
Project code: OIN027-002
Research date: January to June 2016 Date: Updated September 2017
WRAP’s vision is a world in which
resources are used sustainably.
Our mission is to accelerate the move to a
sustainable resource-efficient economy
through re-inventing how we design,
produce and sell products; re-thinking
how we use and consume products; and
re-defining what is possible through re-
use and recycling.
Find out more at www.wrap.org.uk
Document reference: [e.g. WRAP, 2006, Report Name (WRAP Project TYR009-19. Report prepared by…..Banbury, WRAP]
Written by: Dr Jill Doherty (Senior Associate) & Ms Debbie Nesbitt (Senior Scientist)
Front cover photography: Food waste collected for AD treatment.
While we have tried to make sure this report is accurate, WRAP does not accept liability for any loss, damage, cost or expense incurred or arising from reliance on this
report. Readers are responsible for assessing the accuracy and conclusions of the content of this report. Quotations and case studies have been drawn from the public
domain, with permissions sought where practicable. This report does not represent endorsement of the examples used and has not been endorsed by the
organisations and individuals featured within it. This material is subject to copyright. You can copy it free of charge and may use excerpts from it provided they are not
used in a misleading context and you must identify the source of the material and acknowledge WRAP’s copyright. You must not use this report or material from it to
endorse or suggest WRAP has endorsed a commercial product or service. For more details please see WRAP’s terms and conditions on our website at
www.wrap.org.uk
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 1
Executive summary
This guidance document has been prepared by WRAP as part of the industry led Food
Waste Recycling Action Plan (FWRAP). It aims to assist wet Anaerobic Digestion (AD)
operators accepting and treating household food waste from local authorities and the
food supply chain including food manufacturers and retailers.
The guidance has been undertaken in consultation with a number of stakeholder
groups. It deals with the management of liners, in particular polyethylene liners and
aims to summarise the key issues that operators are faced with as well as setting out
standard operating procedures for complying with PAS 110.
In order to increase recycling rates, local authorities are increasingly looking at
developing food waste collection schemes that not only provide a high level of service to
the customer but also enable high participation and capture rates. It is therefore
imperative that effective intervention and collaboration between the AD operators and
local authorities takes place in order to drive this forward.
Liners are often seen by residents as part of the system for collecting food waste and
the results from WRAP’s pilot trials1 demonstrated that the use of liners, especially when
combined with other interventions does increase public participation. Taking this into
consideration, increasing numbers of local authorities allow the use of plastic (PE) liners
in food waste collections as opposed to compostable liners.
Plastics are however one of the main contamination or quality related concern for all AD
systems, and in particular for wet AD systems. If the digestate product visually contains
significant amounts of plastics it will fail to comply with PAS 110.
Therefore, there is a need to ensure that food collection and treatment systems are
closely aligned in order to minimise plastic contamination in the end product. In this
regard, Standard Operating Procedures (SOPS) have been developed to provide a
holistic procedure of the approach to the acceptance and management of food waste in
liners. These are designed to assist AD operators and result in limiting the physical
contamination ending up in digestate. They include:
▪ Contractual specifications;
▪ Pre-waste acceptance procedures;
▪ On site waste acceptance procedures;
▪ Identification of contamination prior to treatment; and
▪ Removal and management of contamination.
A desk based investigation was undertaken into potential innovative approaches that
could be used to increase collaboration between those producing the waste, those
responsible for its collection and the AD operators. This study included input from both
1 http://www.wrap.org.uk/content/food-waste-collections-guide-section-11-increasing-food-waste-capture-existing-separate-week
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 2
AD operators and local authorities as well as a review of best practice in other European
countries. The most popular approaches were as follows:
▪ Collaboration between AD operators and local authorities: This included: the use of
incentives such as production of joint literature, contribution towards the cost of
liners and towards communication campaigns, sponsorship of local events,
provision of grants for local activities and sponsorship of household awards;
▪ Innovation in future contracts. This included quantification of contaminants,
introduction of financial penalties, profit share agreements and variable gate fees;
▪ Visual scoring system. The system could take the form of a series of photographs
used to ascertain the acceptable waste streams and could be included in the input
specification and linked to the payment mechanism; and
▪ Standardised measurement system. There are a number of standardised
measurement systems in use across Europe for determining physical contaminants
in the biowaste industry which could be adapted for use in the UK.
Central to the successful operation of any waste management operation is effective
communication and consultation between stakeholders, especially when waste
producers and collectors are distinct from the operators of the facility. The report
considered a number of mechanisms by which communication and consultation could
be improved. These included:
▪ The development of strategic partnerships in order to facilitate a good working
relationship between all parties;
▪ Regular meetings between all parties. These are considered to be an effective
mechanism for the identification and remediation of any issues as well as ensuring
that all parties are adhering to the contract and the input specifications;
▪ Community events. The hosting of community events is considered effective in
engaging consumers in the AD process from the point of collection through to
demonstration of the end product;
▪ Production of literature including the setting of clear parameters of the feedstock
the facilities can accept and the type of liners that can be processed; and
▪ Increased collaboration with local shops and supermarkets in order to ensure that
the correct liners are being stocked locally.
Finally, the training of staff and development of a programme to entice and sustain
behavioural change will ensure that any measures implemented to improve the quality
of food waste are adhered to.
Staff training and development can take a number of different forms including "on the
job" "off the job" training and E-learning. What is important however is to ensure that it
is all encompassing and that it has participation and buy in from senior management as
well as those "on the ground". During the training staff need to be made aware of why
they are there and therefore focus needs to be provided on the importance of reaching
standards and business continuity.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 3
Contents
1.0 Aim of this Guidance .............................................................................................. 4
1.1 Food Waste Recycling Action Plan ....................................................................... 4
2.0 Contamination ........................................................................................................ 5
3.0 Legislative Context.................................................................................................. 6
3.1 EU Circular Economy Package .............................................................................. 6
3.2 PAS 110:2014 Producing Quality Anaerobic Digestate ..................................... 6
4.0 Facilities in Scope .................................................................................................... 7
5.0 Liner Use .................................................................................................................. 8
5.1 Polyethylene Liner .................................................................................................. 8
5.2 Biodegradable Liners............................................................................................. 9
5.2.1 Bioplastics.................................................................................................... 9
5.2.2 Bioplastics in the wet Anaerobic Digestion Process ............................ 10
6.0 Standard Operating Procedures .......................................................................... 11
6.1 Contractual Specification .................................................................................... 11
6.2 Pre-Waste Acceptance Procedures ................................................................... 11
6.3 On Site Waste Acceptance Procedures ............................................................. 12
6.4 Standardised Inspection Process ...................................................................... 12
6.5 Identification of Contamination Prior to Treatment ....................................... 12
6.6 Pre-Treatment - Removal and Management of Contamination ...................... 13
6.7 Contamination Management Approaches ....................................................... 13
6.8 Front End Removal - Depackaging..................................................................... 13
6.9 Back End Removal ................................................................................................ 16
6.10 External Verification ............................................................................................. 16
7.0 Contractual Arrangements .................................................................................. 17
7.1 Input Specification ............................................................................................... 17
8.0 Innovative Approaches ........................................................................................ 19
8.1 Collaboration between Operators and Local Authorities .............................. 19
8.2 Innovation in Future Contracts .......................................................................... 20
8.2.1 Visual Scoring System .............................................................................. 20
8.2.2 Standardised Measurement System ..................................................... 21
9.0 Improved Communication & Consultation ........................................................ 23
9.1 Development of Strategic Partnerships............................................................ 23
9.2 Regular Meetings ................................................................................................. 23
9.3 Community Events ............................................................................................... 24
9.4 Production of Literature ...................................................................................... 24
9.5 Local Shops/Supermarkets ................................................................................. 25
10.0 Staff Involvement & Training .............................................................................. 26
11.0 Definitions.............................................................................................................. 27
Figures
Figure 1: Potential Types of Feedstocks .................................................................................... 7
Figure 2: Advantages and Disadvantages of Liner Use ........................................................... 8
Figure 3: Depackaging Machinery ............................................................................................ 15
Figure 4: Definitions ................................................................................................................... 27
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 4
1.0 Aim of this Guidance
This guidance document has been prepared by WRAP as part of an industry led Food
Waste Recycling Action Plan (FWRAP). It aims to assist wet Anaerobic Digestion (AD)
operators accepting and treating household food waste from local authorities and the
food supply chain, which includes food manufacturers and retailers.
The guidance has been undertaken in consultation with a number of stakeholder groups
including: local authorities, strategic waste partnerships, industrial groups and AD
operators.
The guidance deals with the management of liners, in particular, polyethylene liners.
The aim of the guidance is to summarise key issues operators are faced with when
accepting food waste in liners. In addition, the guidance sets out standard operating
procedures that are required to be in place to ensure that the outputs comply with the
PAS 110.
1.1 Food Waste Recycling Action Plan
Through the FWRAP, WRAP is working with industry stakeholders to help food waste
collectors maximise and sustain the amount of food waste they collect. This is integral to
securing the supply of food waste as a key feedstock to the Anaerobic Digestion (AD)
and In-Vessel Composting (IVC) sector.
Despite the UK’s best efforts to minimise food waste, there are still 7 million tonnes
wasted every year by households alone, albeit that there will always be a significant
proportion of unavoidable food waste. Increasing the volume of food waste recycled
could provide a huge boost to England’s plateauing recycling rates and help the UK
deliver on the target of 50% recycling by 2020.
Increasingly local authorities are looking at developing food waste collection schemes
that not only provide a high standard of service to the householder but also enable high
participation and capture rates.
Interventions and more collaborative working between the AD operators and local
authorities will play an increasingly important role over time.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 5
2.0 Contamination
Unfortunately, plastic is one of the main contamination or quality related concerns for
all AD but particularly for wet AD systems, where the plastic materials can form a
‘floating layer’ on the surface of the wet digestate. This causes processing and safety
issues associated with trapped gases and flow blockages, potentially resulting in
catastrophic plant explosions.
Shredded plastic particles tend to go through the digestion process with plastic residues
contaminating the visual appearance of the digestate. If the digestate product visually
contains a significant amount of plastics, it will fail to comply with Publicly Available
Specification (PAS 110) and will have to be fine-screened to remove the plastics,
resulting in the requirement for an additional process step. Plastic particles in digestate
do not break down or degrade, are unsightly and lowers the quality of the final product.
It should be noted though; whilst compliance with PAS 110 greatly reduces the amount
of plastics in the digestate, it does not eliminate it completely. Meeting this standard
therefore can result in potentially large amounts of plastic being present. This not only
has the potential to damage soils but also, as a public perception issue, does not always
result in a “clean” product being produced. This can lead to a potential lack in confidence
of the system as well as visual detriment to the receiving area.
The issue therefore is not simply about meeting PAS standard but moving beyond this to
produce the most sustainable and environmentally friendly product as possible.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 6
3.0 Legislative Context
3.1 EU Circular Economy Package
The European Union published a Circular Economy Package in December 2015,2 with the
aim being to stimulate Europe’s transition towards a circular economy which will boost
global competitiveness, foster sustainable economic growth and generate new jobs. The
management and treatment of food waste features high on the agenda of this package
with actions suggested to halve the amount of food waste produced by 2030.
If UK government adopts the EU Circular Economy package this will have the effect of
providing further focus for local authorities and businesses to change their practices in
terms of the future management of this waste stream.
3.2 PAS 110:2014 Producing Quality Anaerobic Digestate
PAS 110:2014 came into effect on 31 July 2014. The PAS is a publicly available
specification and not a full British Standard. It was developed to set out clear guidelines
for operators wishing to deliver a consistent product that complies with industry
specifications. PAS 110:2014 is a non-statutory document3 and does not set regulatory
limit values for the quality and use of digestates. PAS 110 specifies ‘that the AD system is
allowed to accept packaged biowastes/biodegradable non-waste materials that are
depackaged prior to AD’, subject to conditions. For example, reasonable care is required
to be taken to avoid any contaminated wastes, products or materials from becoming
included with the input materials.
PAS110 states that where packaged wastes are accepted there will be a pre-treatment
process that uses reasonable endeavours to remove non-biodegradable packaging prior
to loading those biowastes/ biodegradable materials into the digestion system. Typically,
facilities have depackaging machinery or equipment in place that are capable of
removing all types of packaging.
PAS110:2014 sets clear limits for permitted levels of contamination in digestate. These
limits vary according to the nitrogen content of the digestate, cover all contaminants
materials at a particle size of 2mm or more and include all visible contaminants.
2 http://ec.europa.eu/environment/circular-economy/index_en.htm
3 For food waste to be classified as recycled in Scotland and Wales, local authorities have to send their food waste to PAS110
accredited operations.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 7
4.0 Facilities in Scope
There are three potential types of feedstocks that can go into a wet AD system either
singly or combined:
Figure 1: Potential Types of Feedstocks
Feedstock Feedstock Details In Scope
Food Waste
Domestic food waste.
Commercial and industrial
food.
Energy/Arable Crops
Purpose grown crops
cultivated for their high
calorific value. The key
crops used in the UK are
maize silage, grass silage
and whole crop cereals.
Agricultural Residues
These include animal wastes such as cattle and pig slurry, manures, feed waste and bedding.
This guidance document is primarily relevant to wet AD Operators accepting food waste
feedstock from local authorities. It will also be of interest to AD Operators accepting
commercial and industrial food waste with liner contamination issues.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 8
5.0 Liner Use
Liners are often seen by residents as part of the system for collecting food waste.
Previous trials suggest that residents prefer to use liners so that food waste storage
containers used to securely transfer food from the internal kitchen caddy to the external
bin can be kept clean and hygienic.
Advantages and disadvantages of liner use are as follows:
Figure 2: Advantages and Disadvantages of Liner Use
Advantages and Disadvantages of Liner Use
Advantages Disadvantages
▪ Makes process cleaner for users;
▪ Many users prefer to use liners;
▪ Potentially higher participation rates & yields
achieved;
▪ Potentially higher participation rates;
▪ Collections easier for crews; and
▪ Collection chambers in vehicles are cleaner
and chances of spillages/leakages reduced.
▪ Adds operational costs to the service, if they
are supplied free of charge;
▪ Can be time consuming to set up distribution;
▪ Wastage of liners if distributed inefficiently;
and
▪ Requirement for depackaging equipment.
The type of liner selected for use depends on:
▪ The requirements of the treatment facility;
▪ The cost to the local authority, for example, if liners are provided free of charge to the
users; and
▪ The cost to the users/waste producers, if they must purchase the liners.
To encourage householder participation, some local authorities allow the use of plastic
(polyethylene, PE) liners or standard plastic carrier bags in food waste caddies as
opposed to compostable liners or carrier bags. Current figures from WRAP show that one
fifth of local authorities provide liners to households for food waste collections. However,
a number of local authorities are also considering a switch from compostable to
polyethylene liners. Research carried out by WRAP has shown that there is up to a 32%
increase in food yields (kg/hh/yr) where an intervention package comprising caddy
liners, communications and residual bin stickers are introduced.
Different types of liners, currently used within the waste management industry are
discussed below:
5.1 Polyethylene Liner
Polyethylene (PE) is the most commonly used plastic polymer in the world. Often known
as polyethylene and polythene, its uses include film, packaging and containers, from
bottles to buckets. PE is produced in three main forms:
▪ Low density (LDPE) (< 0.930 g cm-3);
▪ Linear low density (LLDPE) (ca 0.915-0.940 g cm-3); and
▪ High density (HDPE) (ca 0.940-0.965 g cm-3).
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 9
PE is considered a strong, lightweight thermoplastic with very good chemical resistance.
In terms of using PE as a liner, this is primarily referring to film such as:
▪ HDPE – food packaging and shopping bags;
▪ LDPE – cling film and milk carton lining; and
▪ LLDPE – stretch film.
Research undertaken with AD operators has suggested that PE liners are the most
favoured option at the current time, primarily due to the fact that they are easily
removed at both the front end, and where required, from the back end of the processing
system.
5.2 Biodegradable Liners
Two widely available types of biodegradable liners are used for food waste collections:
▪ Compostable liners and compostable carrier bags, for example made from starch
based polymers or biopolymers. They are available in a number of different
specifications based on their size and thickness; and
▪ Paper liners, made from a high moisture resistant paper.
5.2.1 Bioplastics
The term ‘bioplastics’ describes a range of materials with differing properties and
applications, so the term can be ambiguous. Generally, bioplastics are categorised into
three major groups – based on whether a bioplastic is biodegradable, bio-based or is
both biodegradable and bio-based.
The terms ‘bio-based’ and ‘biodegradable’ are not interchangeable, as biodegradable
bioplastics can be made from petroleum and not all bio-based bioplastics will
biodegrade.
The production of all bioplastic materials is forecast to grow in coming years.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 10
Compared to standard polyethylene, most bio-degradable bioplastics have a higher
density typically around 1.25 – 1.3 g cm3.
5.2.2 Bioplastics in the wet Anaerobic Digestion Process
The Anaerobic Digestion Quality Protocol (ADQP) states that biodegradable plastic
packaging that is independently certified to BS EN 13432 or either of the similar
standards DIN V 54900 or ASTM D6400 that is used to collect food waste shall be
permitted.
Several kinds of commercial biodegradable plastics are marketed as being able to
degrade under anaerobic conditions, although in reality most do not degrade quickly
under these conditions.
Products are being developed specifically for anaerobic digestion applications, some
based on PHA (polyhydroxyalkanoate) and quoting results from testing in accordance
with ASTM D5511. Factors affecting the anaerobic digestibility of polymers include pH,
bacteria type, temperature, molecular weight, chemical linkages, and enzymatic access
to the material.
Unless bioplastics are rapidly soluble or dispersible, a form of pre- treatment such as
shredding is required to make them suitable for processing by wet anaerobic digestion.
Otherwise, they may self-segregate by flotation or sedimentation then require removal
and will not actually be digested, even if anaerobically digestible.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 11
6.0 Standard Operating Procedures
These Standard Operating Procedures (SOP) below have been developed for wet AD
operators to give a holistic picture of the approach to accepting and managing food
waste in liners. If these procedures are followed it is thought that they will assist AD
operators and reduce the physical contamination ending up in the digestate.
6.1 Contractual Specification
Key to the success of any contractual arrangement is the effective communication and
improving understanding between the local authority and the AD operators. In this
regard, the implementation of a contractual specification will be key and should:
▪ Identify (or preferably specify) the type(s) of suitable liners. This will require careful
collaboration between the local authority and the operator to ensure that the liners
being proposed are suitable for acceptance at the facility and are in line with the
current (or future proposed) practices within the household collection systems;
▪ Specify the types of feedstock materials that are acceptable;
▪ Agree a methodology to quantify and qualify contamination in waste delivered
(including pricing the contamination where this is considered necessary), how
rejected material, the quality issues and end destinations are reported;
▪ Agree acceptable contamination banded limits; and
▪ Agree a management option for contaminated loads, including processing fees on a
scale, return fees or disposal fees etc.
These actions are described in more detail in Section 8, Contractual Arrangements.
6.2 Pre-Waste Acceptance Procedures
If not dealing directly with the waste producer, the AD Operator could carefully verify the
information received at the pre-acceptance stage. This should include the Duty of Care
information, the contact details of the waste producer and a full description of the waste
with the correct EWC code in order to comply with site permitting.
Consideration should be given to the following:
▪ For each new waste enquiry, a typical compositional analysis should be undertaken;
▪ A representative sample(s) of the waste should be taken from the production
process and analysed;
▪ Screen out unsuitable wastes and confirm any details relating to composition;
▪ Identify verification parameters that can be used to test waste arriving at the site;
▪ Identify any substances within the waste (for example, by-products) that may affect
the treatment process;
▪ Identify any substances within the waste that may react with other reagents;
▪ Accurately define the range of hazards exhibited by the waste;
▪ Identify any substances within the waste that may be unaffected by the treatment
process and transfer in an unaltered state as a residue in the effluent; and
▪ Ensure regulatory compliance with the permit.
It should be noted that the waste producer has obligations under Duty of Care
requirements to provide information on the following:
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 12
▪ Composition of the waste;
▪ Its handling requirements;
▪ Its hazards; and
▪ EWC codes.
This information is required on transfer of the waste from the producer to a third party.
In situations where the waste producer and AD operator are separated by a number of
stages (for example haulage contractors, brokers and waste transfer operators) the
operator should carefully verify the information received at the pre-acceptance stage.
This should include the Duty of Care Obligations, contact details for the waste producer
and a full description of the waste. Within this situation, it is also pertinent to obtain a
representative sample of the waste from the production process in order to ensure that
there are no deviations in composition.
6.3 On Site Waste Acceptance Procedures
The control of feedstock quality at an AD facility is a critical part of the successful
operation of the facility. It is vital both in ensuring that the digestion process operates
efficiently and effectively, and maintaining consistent quality of the outputs. Once the
waste material is onsite, and has been emptied onto the reception area, it should
undergo a standardised inspection process, as agreed between both parties.
Operators should develop procedures to deal with the identification, removal and
management of any contamination. A Hazard Analysis and Critical Control Points
(HACCP) required under PAS 110 will include this.
6.4 Standardised Inspection Process
Inspection should occur immediately if reloading and return are an option and as soon
as possible. Otherwise on arrival, the loads should be visually checked and where
possible, confirmation checks should be undertaken (provided it is safe to do so).
A more detailed inspection should take place immediately after off- loading at the AD
facility. During the inspection, every container should be checked to confirm quantities
against accompanying paperwork.
Please note the inspection, unloading and sampling areas should have suitably sealed
drainage systems.
6.5 Identification of Contamination Prior to Treatment
Should the inspection or analysis indicate that the wastes fail to meet documented
acceptance criteria, then these loads should be stored in a dedicated quarantine area
and dealt with in accordance with the contractual specification and site permit
conditions.
Best Available Techniques (BAT) requires operators to have a clear and unambiguous
written procedure in place for the rejection of wastes. This should include tracking and
reporting procedures.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 13
It is however appreciated that issues do exist where it is considered detrimental to
relations between individual stakeholders to reject loads of material and there is a fear
within the industry that this could lead to the suspension or loss of contracts.
6.6 Pre-Treatment - Removal and Management of Contamination
The removal of contamination is an essential requirement for the production of
digestate if it is to meet the PAS 110 specification.
For waste treatment or transfer, the bulk of the characterisation work should have taken
place at the pre-acceptance stage. This means that acceptance procedures when the
waste arrives at the site should serve to confirm the characteristics of the waste. This
should minimise the waiting time for the delivery vehicle.
Measures to deal with acceptable wastes arriving on-site, such as a pre- booking system,
must be in place to ensure that capacity is available.
The typical objectives of feedstock pre-treatment are:
▪ Removing packaging material from food waste (depackaging);
▪ Removing other non-biodegradable materials, which are not of benefit to the
digestion process;
▪ Providing a uniform and correctly sized feedstock;
▪ Ensuring that the material is particle sized correctly in line with the Animal By-
products (ABP) requirements;
▪ Protecting the downstream plant equipment from materials or contaminants that
may cause physical damage; and
▪ Removing materials which may decrease the quality of the digestate.
6.7 Contamination Management Approaches
The increase in food waste collections has led to an increase in the amount of liners,
both bioliners and polyethylene liners, in the feedstock received at AD facilities.
Operators therefore need to employ reliable front end and/or back end contamination
management approaches to ensure (as far as practically possible) that the output
material will comfortably meet or preferably, exceed the thresholds in PAS 110.
6.8 Front End Removal - Depackaging
The use of liners provides a cleaner and more convenient food waste collection method
for householders and encourages the separation of food waste from mixed household
wastes. AD facilities however have encountered difficulties in processing feedstock
containing liners and in many instances have invested in comprehensive separation
technology to remove the bags from the waste stream prior to treatment.
Depackaging technologies operate using basic physical processes such as compression,
shredding, agitation and screening to separate packaging from its contents.
Compression approaches form the majority of those available. Crushing, shredding and
vigorous agitation of the packaged waste provides the initial stage of opening and
removing food waste from its packaging.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 14
This stage is subsequently followed by a series of separation, screening, washing and
bulking operations designed to maximise the quality of the output and separate
packaging material from the organic matter. These technological approaches are
suitable for separating food wastes from paper/card, rigid and film plastics and metal
cans. Belt press technology is designed for the separation of soft products from
packaging such as paper, card, plastic film, lightweight plastic containers or foil as well as
for other industrial uses such as fruit pulping and meat reclamation. Technologies
incorporating screw presses, hydraulic rams and rotating drums are suitable for the
crushing of heavier packaging including steel and aluminium cans and plastic bottles, in
addition to being able to separate the softer materials.
Investment in effective depackaging equipment will reduce the consequences of the
“drag effect” whereby extra organics may be lost throughout the system as a result of
being separated out with plastic contaminants.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 15
Common depackaging machinery is summarised in the following table:
Figure 3: Depackaging Machinery
Details
Turbo
Separator
▪ Flanged inlet, variable speed, beater blades and breakers bars. Various screens
depending upon product size and consistency.
Belt / Drum
Separator ▪ Flexible squeezing belt and rotating perforated drum
Separator
▪ Screw elevator feed. Batch process rotary action, substrate passed through sieves and
the plastic fraction is washed before passing through an eject hatch aided by a
pulsating compressed air blast.
▪ Washed packaging material contains <1% organic fraction.
Shredder and
Pulper
▪ Slow-running shredders. Dissolution of the organic materials in a pulper and
separation of contaminants.
Shredder and
Screen
▪ Feed hopper, 2 screw conveyors, 2 shredders and a separating screen. Material
sprayed with water.
▪ Liquidised food waste runs back down into a hopper, solid waste is discharged at the
top into a container.
Screw Press
▪ Material fed to screw press via filter chute. Conical outlet remains closed until the
internal pressure exceeds the working pressure. Internal pressure drives free
liquids/pastes through perforated screen discharging separated foodstuff into a
hopper.
▪ Packaging is retained and discharged.
Screw Press ▪ Packaging presses operate electro-hydraulically. Material fed manually into supply
funnel or fully automated conveyors. Separated liquid is collected in a large volume
collection trough and discharged by a separate level-controlled pump.
Pulveriser ▪ Materials fed into pulveriser via an infeed hopper. Twin ‘breaker’ shafts comprising
multi-blade breaker knives which contra-rotate, pulverising the packaging and
releasing the contents against an interchangeable breaker bar grille.
Accelerator
▪ Material accelerated within a chamber results in one material hitting another,
releasing contents from the packaging. Process involves no cutting just acceleration
resulting in low operating costs.
▪ Packaging and contraries are then removed. Organic fraction is broken down with
maximum surface area.
Belt Press ▪ Two stages. Packaging opened and pressed flat in a continuous operation then
cleaned in the second stage. Solids in rinsing water circuit removed, packaging ejected
at the end of the sieve drum.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 16
6.9 Back End Removal
It should be noted however that a study undertaken by WRAP4 has suggested that
although a large proportion of contaminants are removed, depackaging alone may not
be enough to remove 100% of the contaminants. Microfibers and larger fragments may
still end up in the digestate.
Depending on the technology, there may be a requirement for floating material such as
plastics to be removed downstream. This is achieved through a number of mechanisms
including through a rotating skimmer. Here, material is forced to the edge of the
digester where it is removed and separated from any entrained digestate. The
separated digestate is returned to the digestion process and the separated solids
disposed of as residual waste.
6.10 External Verification
PAS is a non-statutory document5 and does not set regulatory limit values for the quality
and use of digestates. External verification and quality standards may improve the
management of contamination.
Other European Countries have adopted more pro-active approaches in terms of
managing contamination. In Germany for example, BGK (the Bundesgutegemeinschaft
Kompost (BGK)) has defined general quality standards (the RAL quality label for
compost, digestion products and sewage sludge compost) and established a nationwide
system for external monitoring of composting and digestion plants and products. The
impact of this is the production of a high quality product with low contamination, with
continual monitoring of standards.
The potential use of these standards is discussed further in Section 8.
4 Enhancement and treatment of digestates from anaerobic digestion
5 If the PAS is used in conjunction with the relevant Quality protocol (QP) the regulator recognised the change of status from a
waste to a product.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 17
7.0 Contractual Arrangements
The operator should ensure that their contractual arrangement with the waste suppliers
clearly sets out how contamination and liner issues will be dealt with. This can be done
using a specification to provide a standard for the quality and types of input materials
that can be delivered for treatment.
This specification should be defined so that it enables the facility operator to produce
marketable digestate compliant with the requirements upon the product.
These might be generated by inter alia:
▪ Licence, environmental permit or other regulatory means;
▪ Quality assurance schemes operated at the facility;
▪ Specifications required of the product; and
▪ Operator desired parameters.
The operator must consider liner types and facility configuration before making
contractual arrangements, creating and agreeing a contractual specification for the
contract duration with the feedstock supplier.
7.1 Input Specification
An input specification will provide guidance on how the input materials delivered
are to be compared to any of the specified quality standards and it defines the
actions to be taken if it is established that the material does not meet the required
standard. Some requirements may also be a requirement of the site’s
Environmental Agency permit.
This specification should:
▪ Have a ‘positive’ list of feedstocks that are acceptable, with descriptions and
definitions. The specification may include a ‘negative’ list of materials that are not
acceptable; Require immediate inspection, if reloading and return are possible, and
as soon as possible;
▪ Agree a methodology to quantify and qualify contamination in waste delivered,
including options to options for a joint inspection if requested. Suggestions for this,
using examples from other technologies and other European Countries, are
presented in Section 8; and
▪ Define the quantity and quality of contaminants that are acceptable, by type. This
should include identification / specification of type(s) of liners, PE or otherwise, in
use. This will depend on the capabilities of the individual facilities depackaging
equipment but should set, at least, maximum permissible amounts of the following:
Total physical contaminants;
Total plastics (including high and low density plastics);
Light plastics (low density plastics e.g. plastic carrier bags); and
Glass (including sharp and rounded pieces).
▪ The setting of these standards will require a great deal of collaboration between the
industry and local authorities but would provide a level playing field of maximum
acceptance levels. Such levels have already been provided for the Composting
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 18
Industry. Consideration should be afforded to consultation with such organisations
such as BGK (as defined in Section 7 and Section 8). This is something which could
be achieved and agreed by the industry without the need to request a change the
statutory status of the PAS system.
▪ Outcomes should be recorded electronically on paper and verified with
photographs to allow later review, if required.
▪ Outcomes of inspections should be communicated to the waste supplier as soon as
possible, particularly where there are adverse findings to allow for joint inspections
and possible load retrieval.
In summary, with regard to contamination, the input specification needs to be
designed to achieve the following:
▪ Agree options for contaminated loads, including scaled processing fees, return or
disposal fees etc.;
▪ Agree options (e.g. processing, return or direct disposal) on how to manage
contaminated loads and their associated fees etc; and
▪ Be reviewed at a frequency, that ensures the maximum acceptance criteria specified
continue to be adequate.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 19
8.0 Innovative Approaches
There are a number of innovative approaches that could be used to increase
collaboration between those producing the waste, those responsible for its collection
and the AD operators. The aim of these should be:
▪ Encourage positive behaviour at the household level to ensure the correct liners are
used (and in general decrease contamination in the source segregated food waste);
▪ Encourage waste collection staff to recognise and intercept contaminated food
waste at the kerbside in order to cut down on contaminated loads; and
▪ By implementing the above, reduce the contamination at source, increase the
quality of the output and hence the profitability of the business.
The type of innovative approach will vary according to a number of factors including the
size of the business and their financial ability and appetite to contribute.
In order to provide some ideas of innovative approaches that could be implemented, AD
operators and local authorities have been contacted and in addition a desk study has
been undertaken in order to ascertain examples that are currently being undertaken
across Europe.
8.1 Collaboration between Operators and Local Authorities
The incentives vary in both cost and complexity but include the following:
▪ Production of literature for issue to householders outlining what can be accepted
and highlighting the types and consequences of contamination;
▪ Issue of newsletters to local residents, highlighting improvements and the
environmental benefits associated with this;
▪ Contribution towards the cost of liners: This will only be considered beneficial to
those householders who currently are required to pay for their liners or where the
Local Authority is considering ceasing the free supply of liners as part of its wider
cost saving;
▪ Contribution towards communications campaigns (for example the circulation of bin
stickers and any promotional leaflets);
▪ Sponsorship for local community events;
▪ Provision of grants for local authority environmental improvement schemes;
▪ Provision of grants for local community education or leisure activities;
▪ Sponsorship of awards for individual households (these would be required to be
nominated by the Local Authority). This could take various forms with examples in
other areas including vouchers for education or leisure facilities, vouchers for local
retailers or restaurants, supermarket voucher, loyalty cards which will lead to
voucher or gifts over time; and
▪ Input of all parties in communication campaigns.
The use of any, or indeed a combination of these incentives will help raise the profile of
the industry as well as acting as a “carrot” for local authority and householder
participation in behavioural change. This will ultimately lead to less contamination at the
outset, the use of the correct liners and ultimately a higher quality output, whilst also
fulfilling corporate responsibility roles.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 20
There will however be a need to ensure that the bureaucracy associated with any of the
schemes can be kept to a minimum in order to ensure that any gains are maximised.
8.2 Innovation in Future Contracts
In addition to innovative approaches from AD operators, there is also the potential for
innovation to be introduced into future contracts to deal with contamination. This would
need to have buy-in from the Contracting Authorities but would, if introduced as a
condition of contract, lead to a level playing field for the industry. These include the
following:
▪ Quantification of permissible contaminants;
▪ Introduction of the ability to include financial penalties for repeated contamination
events (the compensation for this could be negotiated between the two parties);
▪ Introduction of profit share agreements associated with decreased contamination;
and
▪ The introduction of variable gate fees (albeit that there must be a recognisable way
of measurement which will not be financially restrictive to any party).
In terms of quantification of contaminants, a number of mechanisms have been
suggested by current operators and collated through a desk study of what happens in
other European Countries. What is important to remember however is that, at the
current time, there is no definitive figure for measuring contamination and therefore
one system will not “fit all”. The following are therefore to be treated as guidance
purposes only.
8.2.1 Visual Scoring System
This has been suggested as a relatively easy system to implement and control and
would act as a good potential mechanism between waste producers and AD operators.
The system would consist of a number of standard photographs of input waste, each
with differing levels of contamination present. For ease of this report, these could be
titled A to D with photograph A having little or no contamination graded down through
photographs B and C with photograph D having heavy contamination, which would be
therefore unacceptable to the facility. The Organics Recycling Group (ORG) have
produced guidance on visual scoring which includes example photographs.
This scoring could be used to ascertain acceptable waste streams during the input
specification and the payment mechanism between the parties adjusted according to
the wastes received. This system however would require careful control over input
wastes and would require careful inspection and testing of input loads.
It would be extremely beneficial if the permissible contaminants could be quantified in
order to be more understandable outside the immediate operator environment. For
example, calculations of 3% of plastic material within a sample would appear to be a
very small load however, when this equates to approximately 3,500 bags/tonne, it
provides a much more realistic and visual explanation of the issues.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 21
8.2.2 Standardised Measurement System
There are a number of standardised measurement systems in use across Europe for
determining physical contaminants for the biowaste industry. Although these are not
completely transferrable in all cases, they have the potential to act as a starting point for
AD operators as the UK moves towards minimising contamination.
One such system is the Renewable Energy Association’s Biofertiliser Certification
Scheme (BCS) which is part of the overall Renewable Energy Assurance Limited (REAL)
Scheme. This has been created for the purpose of certifying biogas plants against the
PAS110 standard and Quality Protocol (QP) for the production and use of Quality
Outputs from the anaerobic digestion of source-separated biodegradable waste.
The broad approach followed by the Certification Scheme is as follows:
▪ A scheme administrator Renewable Energy Assurance Limited (REAL) develops and
implements the scheme rules and maintains the register of certified participants;
and
▪ One or more independent Certification Body(ies) who certify plants to confirm that
they are operating in accordance with the scheme rules and appropriate standards.
Further information on this scheme, including how to join and details of the training and
guidance available to prepare AD operators for certification is available at: Email:
[email protected] or Telephone: 0207 981 0875
There is a need within the UK however for additional criteria to be included which
provides further consideration of the quality factors associated with the materials. As
previously stated, Germany introduced a RAL Quality label for digestion residuals in
2000 (RAL GZ 246). Within Germany at the current time, there are over 67 digestion
plants taking part in the quality assurance system and have applied for the RAL quality
label.
The quality requirements for this scheme, which could be considered within the UK, are
summarised as follows:
Process Requirements and Suitable Input Materials
▪ Positive list in accordance with ABP Regulation, biowaste ordinance and fertiliser
regulation for digestate products from biowaste;
▪ Operation control by plant visits of independent quality managers; and
▪ Control by independent sample takers and by declaration in analysis report.
Independent Analysis and Declaration of Product Quality
▪ (2) 4- (10) 12 times a year according to the quality guidelines and the amount of
input material;
▪ Control and sanctions by an independent quality committee; and
▪ Certification with product declaration according to the fertilizer and regulation.
Application Requirements
▪ Application requirements based on the biowaste ordinance and fertiliser regulation
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 22
for digestate products from biowaste; and
▪ Application requirements due to good practical use.
Using a similar stance, the Organics Recycling Group (ORG) has provided operators with
a protocol and methodology to measure the levels and types of physical contaminants
delivered in loads of biowaste (protocol to measure physical contaminants in biowastes).
Although developed for the composting industry, there is a great deal of good practice
which could be interpreted for the AD industry and therefore it is considered beneficial
to include within this guidance. The ORG protocol to measure physical contaminants in
biowastes’ provides guidance on how the input materials delivered to a composting
facility shall be compared to the input quality standard and defines the actions to be
taken if it is established that the material does not meet the required standard. The
document provides operators with a methodology to measure the levels and the types
of physical contaminants in delivered loads of biowastes. This enables operators to:
▪ Ascertain and monitor contamination levels in loads of biowaste delivered to
organics recycling facilities;
▪ Obtain evidence to support the specification or revision of maximum acceptance
criteria in contractual arrangements with suppliers;
▪ Check compliance with the acceptance criteria specified within existing contractual
arrangements;
▪ Provide biowaste suppliers with feedback on specific collection rounds that are
routinely causing issues with respect to contamination; and
▪ Justify the implementation of a differential pricing mechanism based on the results
of the assessment carried out.
The methodology for achieving assessment of levels of contamination is based on a
methodology implemented by the Italian Composting Association (CIC) and describes:
▪ How a representative sample should be obtained from a load of biowaste delivered
to the facility;
▪ How the sample should be sorted to differentiate between bio treatable and non-
bio treatable fractions; and
▪ How the results of the assessment should be provided.
ORG recognise within the protocol that this methodology can be used to assess
contaminants in AD facilities through the identification and use of difference categories
of physical contaminants. Further information on the ORG system can be found here
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 23
9.0 Improved Communication & Consultation
Effective communication and consultation is considered key to the successful operation
of a waste management facility, especially when the waste producers and collectors are
distinct from the operators of the facility.
The aim of this section is to provide some guidance on improving communication and
consultation, with the overall objective of ensuring that a high quality product can be
produced in the most cost effective and sustainable manner.
9.1 Development of Strategic Partnerships
Consultation with a number of AD operators, groups and Local Authorities has
suggested that the formation of Strategic Partnerships facilitate a good working
relationship between all parties.
A Strategic Partnership has been described as a formal alliance between 2 or more
enterprises, usually formalised by 1 or more business contracts. Within this Partnership,
parties agree to share finance, skills, information and other resources in pursuit of
common goals.
This is considered particularly useful in the AD industry, as often AD operators do not
have the opportunity to interact directly with the waste producers. Within the UK, for
example, our consultation has alerted us to the fact that there may be waste collection
representatives, transport companies, waste transfer stations in the chain before the
waste reaches the AD operator. Within this chain, there can understandably be a
challenge in the dissemination of information between all parties. The formation of a
partnership approach would aid in this manner and ensure that all stakeholders are
aware of their responsibilities and obligations.
This would also help to alleviate any potential issues where it is considered as purely
one party’s responsibility to deal with quality of the materials or contamination, often
with no financial detriment to others.
9.2 Regular Meetings
Regular meetings between each of the interested stakeholders is considered to be a
useful mechanism of continuing communications. The timeframes for these will be
project dependant but it has been suggested that quarterly meetings may be useful.
This meeting could be used for the identification and remediation of any issues,
including contamination issues and will be a good forum for ensuring that all parties are
adhering to their aspects of the contract and any associated input specification. Regular
meetings would be useful for those operators who are in a chain of treatment, and are
therefore not in direct contact with the waste producers. In this instance, it would be
beneficial for a representative from each of the interested stakeholders to be present as
all will have different agendas.
These meetings should be properly minuted and associated actions disseminated to all
parties. The meetings could include the following:
▪ The types of liners which cause problems in the anaerobic digestion process for the
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 24
AD plant and how the local authority can help prevent these entering the food waste
stream;
▪ The percentage of liners received from a particular local authority and percentage of
liner types causing problems (or not, as the case may be);
▪ New innovations in bag liners, which may be more suitable for the AD process, and
associated costs of such liners for the local authority;
▪ What types of liners other local authorities/AD plants are using and where they
sourced those liners from;
▪ Technology innovations within the AD plant which may mean that certain types of
liners can be accommodated more easily in future;
▪ Possible ways for a number of local authorities who supply a particular AD plant to
obtain economies of scale in the purchase of suitable liners; and
▪ Forthcoming local authority food waste communications campaigns and the
possibility for the AD plant to comment on any proposed communication before the
campaign is launched.
9.3 Community Events
The hosting of community events is considered an effective way of raising the profile of
the industry and showing consumers, not only the end products of their waste, but also
highlighting the importance of minimising contamination at source. Operators have
reported benefits of engaging with a number of community groups in this manner and
would suggest that this is an effective way of disseminating information to the wider
community. Events could take a number of different forms from illustrated talks outside
of the site to on-site tours and events. Hosting events with Local Authorities and their
collection service crews is another effective to way to promote the importance of input
quality.
9.4 Production of Literature
For the AD Operator, generating enough biogas to make the operation financial viable and
producing digestate of the highest quality, as a result of good process management is
key to the success of their operation. In order to achieve this, it is vital that they set clear
parameters of the feedstock they can accept, including which type of liners their AD
plant can process. To help clarify their position on liners, AD operators should consider
producing an A5 size leaflet outlining the specification of the liners their plant can deal
with. This should be circulated to all local authorities who supply feedstock to that AD
plant and should be available on the AD Operator’s website. The information on this
leaflet should be discussed at any pre-contractual meeting with a local authority who is
planning to introduce a food waste collection scheme.
This would help local authorities ensure they are purchasing the correct liners to supply
residents with and which will comply with the AD plant.
If the AD Operator is in a position to suggest suppliers of liners, this could be helpful to
the local authority to ensure they are purchasing the correct liners from the outset. In
addition, it would benefit AD Operators to have some input, or at least comment on, any
food waste communication leaflet provided by the local authority to their residents. It
may be the case that the AD operator can assist with the wording in this section to
better improve overall uptake of the scheme.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 25
9.5 Local Shops/Supermarkets
It is quite often the case that householders have to buy liners for their food caddy in
local shops/supermarkets. In this case, AD operators would be advised to ask to speak
to the general manager of these stores and explain their position on the preferred type
of liner their plant can process. If the AD operator can ensure that the local shops/
supermarkets are supplying the correct bag for their system then this can only be of
benefit to both the AD operator, the householder, the supermarket and the local
authority.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 26
10.0 Staff Involvement & Training
Staff training and involvement can take a number of different forms. What is important
though is that it is all encompassing and has participation and buy in from senior
management as well as those operating “on the ground”.
Due to the importance of buy in from all sectors, whenever possible training should
include both the AD operators and those supplying the waste, i.e. for household food
waste- local authorities and where necessary waste collection authorities. It would also
be an effective mechanism to ensure that all parties were aware of their responsibilities
in collecting and treating a waste which produces a high quality end product, with
minimal contamination. A reduction in contamination from the outset, combined with
the systems within the AD facility will undoubtedly result in a higher quality product.
Signage should be clearly displayed within both the waste acceptance areas and within
the operational areas in order to remind staff (and highlight to customers where
relevant) of their roles and responsibilities in terms of minimising contamination.
Staff training can take various forms, and should be adapted according to the desired
audience. Employers can choose from “on the job training” and “off the job training”
depending on their specific objectives.
Health and Safety needs to be given priority during these training sessions. Employees
need to be sure of how to remove contaminants during the AD process without
compromising the health and safety of themselves or anyone around them.
One further important issue to take into consideration is to ensure that employees are
aware of why they are undertaking this training. The training sessions do therefore need
to provide some focus on the importance of reaching standards for reaching standards
and business continuity. It may be useful to use feedback from customers on the quality
of the organic output produced (i.e. include details of any contaminants/types of
contaminants still present).
Finally, it will be extremely beneficial for employers to follow up training sessions. Not
only will this act as a timely reminder on requirements and expectations, but can also be
used to highlight improvements in the quality of output produced.
WRAP – Industry Guidance: Dealing with Household Food Waste at AD
Facilities – Management of Liners 27
11.0 Definitions
The following definitions are used in this guidance:
Figure 4: Definitions
Anaerobic
Digestion (AD)
Process of controlled decomposition of biodegradable materials under
managed conditions where free oxygen is absent, at temperatures suitable
for naturally occurring mesophilic or thermophilic anaerobic and facultative
bacteria species that convert the inputs to biogas and whole digestate.
Aerobic Oxygen source available
Anaerobic No oxygen source available
Anaerobic Digestion
Quality Protocol
(ADQP)
End of waste criteria for the production and use of quality outputs from
anaerobic digestion of source segregated biodegradable wastes.
Biodegradable
(liner)
Those liners which can be broken down into its constituent monomers and
metabolised through the action of naturally occurring micro-organisms, such
as bacteria and fungi, over a period of time.
Biogas Gas generated by an anaerobic digestion process. Typically composed of 60%
methane and 40% carbon dioxide.
Compostable
(liner)
Those liners which are capable of undergoing biological decomposition
breaking down into carbon dioxide, water, inorganic compounds, and
biomass, at a rate consistent with known compostable materials
Digestate, Fibre Fibrous fraction of material derived by separating the coarse fibres from the
whole digestate.
Digestate, Liquor Liquid fraction of material remaining after separating coarse fibres from whole
digestate.
Digestate, Whole
The residue resulting from the anaerobic digestion of biodegradable materials.
Whole digestate may be separated into liquor and fibre fractions, referred to as
liquid and solid digestate respectively.
Dry solids (ds) Measure of solids content within the digestate. Defined as the % of mass
remaining after drying at 105°C.
Moisture content Measure of water content within the digestate. Defined as the % of mass lost
after drying at 105°C.
Separated fibre Fibrous fraction of material derived by separating the coarse fibres from the
whole digestate.
Separated liquor Liquid fraction of material remaining after separating coarse fibres from whole
digestate.
PAS 110
Publicly Available Specification 110, which is the British Standards Institution’s
specification for whole digestate, separated liquor and separated fibre derived
from the AD of source-segregated biodegradable materials, published in
February 2010 and revised in 2014.
www.wrap.org.uk/organics