Guidance for MRF sampling requirements permits use of AI technology

Defra sets out the scope for materials facility operators to develop a methodology that meets the Environmental Permitting (England and Wales) (Amendment) Regulations 2023 that will apply to them from this October.

Recyclables at a materials recycling facility are going to be subject to new sampling rules from October 2024These regulations mandate Materials Recovery Facilities (MRFs) in England and Wales receiving over 1000 tonnes a year must adopt standardised procedures for sampling and measuring waste.

This guidance offers a roadmap for MRF operators to develop, document, and implement a sampling methodology that is compliant with the law and tailored to the particular operational characteristics of their facilities. Recognising the diversity in waste types and facility operations, the guidance identifies the importance of flexibility, allowing methodologies to be adapted to various contexts, whether facilities handle waste in loose, bagged, or baled formats.

A core component of this is the establishment of a systematic process for taking representative samples of waste. The guidance sets out the need to devise a process designed to account for the variability of input waste streams, including differences due to supplier, the form of waste, and seasonal changes. With an emphasis on accuracy in the sampling process, the guidance provides instructions for the use and calibration of weighing equipment and the accounting for moisture content and other potential contaminants in the waste.

Moreover, Defra outlines the need to document staff training programs that provide the necessary skills for accurately taking samples and categorising different types of materials. This includes the differentiation between target and non-target materials and the identification of packaging materials, necessary for the precise sorting and recycling of waste.

Operators are permitted to use visual detection and recognition technology, including vision-based artificial intelligence systems, but if they choose to do so, they will need to ‘measure, record and be able to demonstrate to the regulator how their sampling methodology meets the regulations and produces representative sampling results, whatever technology is in use’.

Sampling guidance

The number of input samples should be determined based on the overall weight of input waste material delivered by each supplier, with more material necessitating more frequent sampling. Considering the tonnages from each supplier guides the determination of sample numbers for that supplier. Reflecting on data from the same reporting period in the previous year should provide a representative estimate.

Handling irregular suppliers—those who deliver waste sporadically or in smaller amounts—requires a specific methodology to decide when and how to sample their deliveries, such as taking a sample for every 75 tonnes of waste received during a reporting period.

In sampling waste materials, either incoming or outputs, the guidance recognises the need to avoid equipment damage and preserve sorting integrity by removing large, potentially harmful items. It recommends selecting sampling methods based on the waste's form - loose, bagged, or baled - to ensure the samples accurately reflect the material's composition. Operators are asked to adopt techniques to distribute items evenly or adapt to the waste type to ensure representative results.

The sampling approach needs to account for the material's variability, with strategies like the 'points of a compass' technique for bagged waste or random selection of bales, to ensure an accurate picture is obtained.

Smaller MRFs

For smaller operators without sufficient space for onsite sampling, offsite sampling presents a viable alternative that can still meet  regulatory requirements. Developing an offsite sampling methodology requires implementing a sample gathering approach that captures the variability of input and output material accurately.

To prevent cross-contamination, samples should be stored in sealed or covered containers before transport to the offsite location. Proper labelling or identification of these containers is essential to ensure that analysis results are correctly attributed to each supplier. Additionally, to maintain sample integrity and ensure timely data reporting within the relevant period, small MRFs are advised to minimise the delay between sample collection and its analysis at the offsite location.


Beyond the technical aspects of sampling, MRFs are asked to prioritise health and safety. Operators are responsible for ensuring that staff undertaking sampling activities are adequately trained, both from a practical standpoint and in health and safety compliance. The guidelines suggest consulting the Health and Safety Executive (HSE) for specific risk assessments, personal protective equipment (PPE) requirements, and control procedures relevant to sampling activities.

The regulations set to be implemented from October 2024 cover a range of waste types, including materials originating from residential settings intended for recycling or reuse. Additionally, they cover similar non-household waste, encompassing waste from commercial, industrial, or other sources that bears a resemblance in nature or composition to household waste. This means that facilities managing waste from a variety of origins, but akin to household waste in characteristics are covered.

Included within the scope are facilities dealing with single stream waste, which consists of only one type of material such as paper, glass, or plastic. Moreover, the regulations also apply to mixed stream waste, which involves waste containing a mixture of materials. This can include a blend of glass, metal, paper, plastic, and fibre-based composites. The focus extends to facilities that sort these mixed streams into separate, specified output materials, which are the differentiated waste material streams produced post-sorting.

The regulations delineate exclusions for facilities solely engaged in specific types of waste processing activities. This encompasses entities that only receive waste material from a single supplier without segregating it into specified output materials, as well as facilities solely dedicated to the processing or sorting of waste electrical and electronic equipment (WEEE), waste batteries or accumulators, or exclusively focusing on the sorting and processing of residual waste.

Defra claims that compliance with the enhanced regulations for Materials Facilities (MFs) will be rigorously enforced by the Environment Agency or Natural Resources Wales. Facilities identified as MFs will undergo both announced and surprise audits, which might include on-site inspections or virtual assessments, as well as evaluations of data submissions to verify the accuracy and representativeness of samples, along with the integrity of recorded and reported data.