A snappy solution for nappy recycling

The UK’s first recycling facility for nappies and incontinence products is to open in January next year. Planning permission has been granted for the 2,600m2 plant in Tyseley, Birmingham, to be built and operated by Knowaste. It expects to handle 36,000 tonnes of nappies and other absorbent hygiene products, including bed liners and incontinence products – some 5% of total UK waste of this type.

“This will be our new state-of-the-art facility when it’s built,” says Know-aste’s chief executive, Roy Brown. “We had our main plant in Arnhem in the Netherlands until 2007. It was a little over 10 years old and did not reflect the new technology and the money to upgrade it was better spent in coming to the UK.”

High recovery rate
The Knowaste process enables 98% of the disposable nappy or adult incontinence product to be removed from the waste stream and recycled into a variety of products, from shoe insoles and wallpaper to plastic wood and thickener for industrial products.

According to Brown, there will be a “market-driven, competitive gate fee, making our process attractive against landfill or other disposal options.”

He adds: “The UK has unique advantages in that landfill is the predominant disposal option. We can [recycle nappies] economically and EU directives are driving some of the regulation here, which is to our advantage. It makes a lot of sense to recycle and we can do it economically.”

The use of disposable nappies and other absorbent hygiene products, including bed liners and incontinence products, has increased dramatically over the past 20 years because of their convenience, especially for institutions. In the UK, around 8M disposable sanitary products are used every day and almost all are disposed in landfill sites. Apart from the limited incineration capacity available in the UK, this sort of waste has a burn value of between 4 and 6, well below the 11 required by EU regulation for incineration.

A typical disposable nappy or incontinence product comprises mixed plastics, wood pulp and super absorbent gel polymers. The mixed polymers makes up the nappy’s inner and outer layers with cellulose material and super absorbent polymers inside the product that retain moisture and keep it from the skin. The super absorbent polymers make these products problematic to recycle.

Knowaste’s patented technology uses a variety of salts, generally aluminium sulphate, to deactivate the polymer. Further processes separate the cellulose fibres, plastics, absorbents and other contaminants. “That allows us to focus in on marketable products and to work with those, for example, the plastic. By doing further washing and treatment we can pelletise them for use in any really thick injection moulding processes,” explains Brown.

To conserve resources throughout the recycling process, water is captured from each wash cycle, treated, and then reused in the system. All the individual components of a disposable nappy can be recycled, claims Brown. “Our technology allows us to completely separate and clean the pulp or cellulose that can be separated out to make a variety of recycled products like high quality paper. Nappy material generally has a very long fibre and is of high quality.”

But this will not happen at the Tyseley facility because UK market demand for pulp is poor with prices too low to be of interest to the company. “It doesn’t mean that we cannot change in the future, but in the interim the pulp will go into the cake stream used to create methane for electricity generation off the site,” says Brown.

The site is physically too small to allow on-site generation and Knowaste will co-venture electricity generation, as it does with waste collection. Birmingham-based waste contractor, Alpha Wastecare is the chosen partner for collection.

“We chose to third-party all collection as our core competence is in the processing,” explains Brown. “Their focus will be, by and large, commercial waste institutions. Civic amenity sites would be suitable for providing domestic collection points and we would be delighted to work with people wanting to provide this. But the volumes are with the institutions.”

Customisation possible
Knowaste’s recycling technology can be customised to support small demonstration projects in a single community or scaled-up to service a regional recycling program, as in Birmingham. This flexibility allows the company to market to a diverse and growing group of interests including waste management companies, local authorities, product manufacturers and hospitals.

The company argues that with its process there is no longer a cost barrier for organisations committed to environmental protection but which have lacked the funds or space to construct a large facility. A small Knowaste plant, with an operational footprint of 140m2, can process up to 5,000tpa of used nappies and hygiene products.

Knowaste was established in 1989 and specialises in developing environmental solutions for difficult waste streams. In the Netherlands, the company processes up to 70,000 tonnes of nappies and hygiene products, 65% of the market. In 2007, it handled 8,000 tonnes of similar waste from Germany and in the same year launched the system in the UK with its application to build the facility in Birmingham.

Dean Stiles is a freelance journalist