Bridging the gap

RPS principal consultant Claudia Amos and consultant David Rodgers study ways of determining end markets and uses for waste-derived products

The gap between the outputs from waste treatment and the marketable products required for utilisation in different industries is one of the major barriers to successful use of waste-derived products. These discrepancies influence the utilisation of secondary products but they can be bridged to determine end-user markets and enable the efficient reuse of valuable materials in an Integrated Resource Recovery System.

In the UK, as in many other European countries, recycling activities for numerous waste streams are being driven by major regulatory initiatives. In the public sector, individual local authorities have a mandate to divert municipal solid waste from landfill to meet the statutory recycling targets set by the Best Value Performance Indicator scheme, as well as the Landfill Allowances Trading Scheme. In the commercial and industrial sector the developing suite of producer responsibility legislation for packaging, end-of-life vehicles, waste electrical and electronic equipment etc, is leading to increased levels of recovery and recycling to meet voluntary and statutory industry obligations for post-consumer products.

Most of the current legislative drivers and the subsequent activities in the different sectors are focused on the actual waste collection, recycling and recovery of waste to avoid landfill disposal as an undesirable environmental option. These regulatory drivers have led to the development of a collection, recovery and recycling infrastructure, which is currently being implemented throughout the UK.

Closing the material loop

In contrast to landfill disposal, the recycling and recovery processes being introduced are not end-of-pipe solutions, but should be part of an IRRS. All these processes attempt to recover value from waste by producing a range of output streams that could enter new markets and replace primary resources to close the materials loop and increase resource efficiency. However, there is a significant market imbalance in the amount of outputs derived from waste compared to demand for such products.

The table below provides an overview of selected outputs from some waste recovery processes and how these could be converted into marketable products. The characteristic of a marketable secondary product can be described as follows:

  • the waste-derived products need to have a market value, ie, a demand for this product. Where a demand cannot be created or cannot be created at the right price, materials will need to be treated further or be disposed of; or
  • the quantity and quality of product needs to meet the expectations and requirements of the subsequent user to provide a sustained supply replacing virgin resources.
  • Not all outputs will create marketable products, because every recycling and recovery activity produces rejects and residues for disposal. The amount going to disposal can be substantial and varies from 5-50% of the input, including process residues and rejects from the input waste stream.

    Subsequent recycling activities will produce additional rejects as the total amount accepted for recycling can often not be reused within the original production process. This shows that in reality 100% resource recovery and "zero waste" are not realistic goals, but it also suggests that currently resource recovery is not efficient and needs to be improved in the future to ensure markets for secondary products can be created in order to recover value from waste.

    Waste derived outputs to marketable products

    Selected waste streams* Recycling and recovery process Outputs Output preparation and post-treatment Marketable product
    Mechanical/physical waste treatment
    End-of-life vehicles
    Waste electronic and electrical equipment
    Batteries
    Disassembly and bulking stations Plastics, metals, glass, tyres, oils, chemicals Cleaning, separation and conditioning Secondary aggregate, paper, glass/cullet, plastics, metals, oils, chemicals etc, to replace virgin materials
    Source segregated - dry recyclables collection (glass, metals, paper, plastics, textiles) Clean material recovery facilities (MRF) Glass, metals paper, textiles, plastics Cleaning, separation and conditioning Secondary aggregate, paper, glass/cullet, plastics, metals etc, to replace virgin materials
    Biological waste treatment
    Source segregated -green and garden waste Windrow composting Humus, rejects Maturation, screening and conditioning of humus Quality compost (BSI PAS 100)
    Source segregated - kitchen, green and garden waste
    Commercial and industrial organics and sludges
    In-vessel composting Humus, rejects Maturation, screening and conditioning of humus Quality compost (BSI PAS 100)
    Source segregated - kitchen, green and garden waste
    Commercial and industrial organics and sludges
    Anaerobic digestion Biogas, humus, liquids, rejects Gas cleaning, conversion into transport fuel and/or electricity/heat, maturation, screening and conditioning Transport fuel, renewable electricity, renewable heat, liquid fertiliser, quality compost (BSI PAS 100)
    Thermal processes
    SRF/RDF/fibres
    Automotive shredder residue (ASR)
    Electrical and electronic shredder residue (EESR)
    Sewage sludges
    Pyrolysis and/or gasification Syngas, char, pyrolysis oil, ash, slag Gas cleaning, conversion into fuels and/or electricity/heat milling and conversion of char outputs Renewable electricity, renewable heat, ethanol, hydrogen, other chemical precursors, carbon black/activated carbon
    SRF/RDF/fibres
    Automotive shredder residue (ASR)
    Electrical and electronic shredder residue (EESR)
    Sewage and industrial sludges
    Fluidised bed combustion Flue gas, ash Gas cleaning, conversion into electricity and heat Renewable electricity, renewable heat
    Hybrid processes
    Mixed MSW
    Black bag/bin waste
    Residual grey bag, bin waste
    Mechanical biological treatment (MBT/BMT) using composting or bio-drying Dry recyclables (inerts, glass, metals, plastics)
    Solid recovered fuel (SRF)
    Refuse derived fuel (RDF)
    Humus
    Cleaning and separation of dry recyclables
    Preparation/pelletising of SRF/RDF as secondary fuels
    Stabilisation of humus products
    Secondary aggregate, glass/cullet, plastics metals etc, to replace virgin materials
    Secondary fuels to replace fossil fuels
    Soil improver
    Mixed MSW
    Black bag/bin waste
    Residual grey bag, bin waste
    Autoclaving/ mechanical heat treatment Dry recyclables (inerts, glass, metals, plastics)
    Fibres/solid recovered fuel (SRF)
    Cleaning and separation of dry recyclables
    Preparation/pelletising of SRF as secondary fuels
    Secondary aggregate, glass/cullet, metals etc, to replace virgin materials
    Secondary fuels to replace fossil fuels
    *Not all suitable waste streams are listed for each waste process
    Source: RPS Planning, Transport & Environment

    In order to bridge the gap to market, most outputs require various levels of conditioning/post-treatment and even additional waste treatment to convert the output into a marketable secondary material and/or product. In many cases, conditioning is already part of the overall waste treatment process.

    Examples include the maturation and screening of compost or the electricity/heat production after thermal waste treatment. Some hybrid processes such as MBT/BMT have been developed to further integrate waste treatment and the production of secondary material.

    Integrated waste management

    Today, integrated waste management is becoming standard practice to recover value from waste instead of landfill disposal. However, IWM focuses on the optimised integration of waste treatment activities in regard to waste flows, proximity and landfill diversion. In contrast Integrated Resource Recovery Systems are aimed at producing marketable products through waste treatment to close the materials loop and increase resource efficiency.

    Sometimes, these are described as eco-parks or resource recovery parks (see page 35), which refers to the optimised integration of producers and users of waste-derived products at close proximity. The concept of IRRS is not restricted to eco-parks, but promotes the idea of optimised utilisation of waste as a valuable resource within the public and private sector as a sustainable approach for the future.

    So, how can this be achieved in the future and how can waste management producing valuable outputs evolve into resource management creating marketable products? In an economic environment the markets for waste-derived products are driven by demand and supply indicated through the associated price mechanism.

    Regulatory forces are distorting the market to protect public health, society and the environment. Due to the costs of waste treatment and preparation, most waste-derived resources are currently more costly than their virgin equivalents. In consequence, most markets for secondary products will be distorted to avoid the currently cheapest, but undesirable option of landfill disposal.

    Secondary product markets and regulatory distortion in the UK

    Level of integration Regulations/market distorters Examples of waste derived products
    Secondary products with established markets Renewable electricity obligation (RO) and RO certificate trading system/climate change levy
    Packaging regulation - recovery notes
    Tax on primary aggregates

    Building/cement industry standards
    Renewable electricity
    Paper, glass, ferrous metals, aluminium, plastics, wood
    Inerts, glass residues, other secondary aggregates
    PFA in cement, building products and civil engineering use
    Secondary products with emerging/developing markets BSI PAS 100 (revision)
    Animal-by-product regulation
    Review of ROC criteria for waste to energy production

    Civil engineering standards

    Incentive system for transport fuels
    Development of quality standards for low quality compost
    Compost

    RDF/SRF/fibre to replace fossil fuels

    Bottom ash use in civil engineering projects

    Ethanol, hydrogen, pyrolysis oils
    Low quality humus products, soil conditioners
    Note: This table only provides an overview of selected outputs. It does not address the efficiency of these markets.
    Source: RPS Planning, Transport & Environment


    Addressing waste treatment

    Most regulatory drivers and incentive systems are still focused on waste treatment, ie the supply of waste-derived materials, without addressing the utilisation of outputs and marketable products to the same degree. The renewable electricity sector is one of the few areas where the utilisation of waste-derived products is being stipulated.

    However, not all types of waste-to-energy products are included under the Renewables Obligation, which leads to market distortion towards certain waste treatment technologies and input streams. The government's Green Procurement Initiative attempts to promote the purchase of recycled products within the public sector as part of the Sustainability Programme, which could be a very promising concept to encourage the utilisation of secondary products and green resources. Today, most markets for secondary products are reliant on softer measures such as quality standards and material acceptance criteria to establish confidence in waste-derived products and subsequently stimulate demand. The rising amount of waste-derived products going to landfill or being processed as waste for a gate fee shows that this approach might not be sufficient to address the market imbalance that currently exists.

    Sustainable markets for waste-derived products need to be sustained and created in the short to medium-term future. Therefore more wide ranging measures need to be considered to encourage efficient use of resources. The concept of an IRRS addresses these growing concerns about finite future resources.

    IRRS attempts to find an economic and environmental balance between the utilisation of virgin and secondary resources by all sectors of society and considers waste treatment from a different perspective. IRRS concentrates on the creation of valuable products with sustainable markets instead of solely focusing on waste management in isolation.

    This will have implications for the selection of suitable waste treatment processes, as it will lead to a prioritisation of waste technologies that can produce valuable and marketable products. It will also influence the way waste contracts are structured, the siting and planning of new facilities as well as the way new waste treatment infrastructure will be funded.

    It will require the co-operation and strength of all waste industry players and regulators to move from an integrated waste management for different waste streams to an IRRS, which concentrates on recovering value from waste and efficient resources utilisation.


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