Suez embarks on nappy research

France – One million tonnes of nappies, or diapers, are thrown away in France every year. Together with wet wipes and other paper tissues, these nappies are included within the ‘sanitary textiles’ waste category – volumes of which are continuing to rise and currently amount to an average of 34 kg per inhabitant per year, or 9% of overall household waste.

French waste management firm Suez Environnement, with the major projects department of its subsidiary SITA, is undertaking research aimed at assessing the potential for recycling nappies; this Euro 340 000 programme has received 40% funding from ADEME as part of the call for eco-industrial project bids organised in 2009. A laboratory-scale research phase will be conducted at CIRSEE – Suez Environnement’s research and development centre – in order to confirm the industrial feasibility of the assumptions and their environmental benefits, as well as their technical and economic validity.

The research programme consists initially of testing a pilot project that assesses the potential for recovering energy and material from the nappies’ component parts. The first stage of the pilot involves crushing the used nappies in order to isolate the various constituent materials: plastics 10-20%; super-absorbent polymers 5-10%; fibres 10-20%; and organic waste (faecal matter and urine) 50-70%. The different materials can be recycled only once they are separated and isolated. The research programme aims to achieve a triple recovery objective: production of energy through biogas from organic waste; recycling of plastic; and production of compost from the residual organic waste.

The nappy recovery principle is based on co-digestion whereby the organic waste from the used nappies is mixed and fermented with sludge from the wastewater released by Lyonnaise des Eaux treatment plants. The co-digestion will provide the biogas.