Water & Wastewater Treatment

10 | FEBRUARY 2015 | WWT | www.wwtonline.co.uk Comment W aste reduction is without any doubt a buzzword in the industry in recent times. With increasing pressure on landfill space across Europe, the introduction of the Waste Framework Directive and the Landfill Directive attempts to deal with this issue and encourage a greater awareness of the potential that exists for the recovery of materials previ- ously sent to landfill. What has emerged as this discussion has developed is that rather than activity in this area simply being a requirement of new EU legisla- tion, it actually offers everyone in the industry an opportunity to make their businesses much more efficient through the elimination of unnecessary waste disposal costs. Across a wide range of materials, from sewer grit to road sweepings and gully waste, there is a realisation that this material has the potential to be a valuable resource if the appropriate process- ing technologies are employed in its treatment. CDEnviro has installed several recycling Red tape stands in the way of waste minimisation Technology increasingly allows the recycling and reuse of water industry waste such as sewer grit, but its development is being stifled by the environmental regulator's caution systems for sewer grit at various sewerage treat- ment works throughout the UK. These plants are processing sewer grit from the inlet works and in some instances are also acting as a central re- cycling facility for imported wet waste captured at other smaller treatment plants. Sewer grits are typically a minor waste stream with ap- proximately 40,000 tonnes generated each year from thousands of wastewater treatment works (Source: WRc) As sewer grit is more than 90% mineral mate- rial, there is significant potential for this material to be cleaned and dewatered and made suitable for further use. The treatment process involves a variety of processing phases including attrition, high frequency screening, efficient fines removal, dewatering and stockpiling. While the initial purchase decision is made on the basis of a diversion of waste from landfill, the ability of the system to produce a clean, dry grit and recycled aggregate product has been recognised by the major water utility companies. In response to this they have carried out consid- erable market research with local construction contractors in an effort to establish whether there is a commercial application for this mate- rial. The response to these approaches has been extremely positive with the general feeling being that contractors would be more than happy to use this material if all the required certifications were in place. Grit washing provides a practical option for this type of material for the water utility com- panies, as in most cases the equipment can be retrofitted to existing plants and can also process road sweepings and gully wastes. Accepting third party wastes could maximise the use of the equipment and potentially generate additional revenue. However, at present the Environment Agency in the UK has issued a 'Guidance on low risk waste activities' which deals with both sewer grit and road sweepings. Currently this guidance allows for these recycled materials only to be used in a very limited field of application and this restriction is stifling the development of this industry. In the absence of certification allowing for the more widespread use of these recycled materials, the full potential of these new processing tech- nologies to reduce the volumes of this material going to landfill will not be realised. Both equipment manufacturers and the industry as a whole have demonstrated a commitment to tackling waste reduction and maximising the value of the recycled products. Unfortunately, the Environment Agency has not demonstrated the sense of urgency that is required if we are to fully exploit the opportunity that is presented by sewer grit, road sweepings and gulley waste. Peter Craven is head of marketing at CDEnviro, who produce a range of equipment allowing opera- tors in the wastewater treatment, utility waste and industrial sectors to significantly reduce waste volumes and maximise material for re-use. Peter Craven CDEnviRo Recycling taking place at a plant in northern ireland.

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