Composting research and solutions to meet the UK's requirements for waste management

As waste management and landfill regulations are changing dramatically, Patrick Pierrepont of advisory service ADAS looks at extensive research and composting solutions that are currently be investigated and delivered in order to meet the changing national agenda.

Last summer saw the unveiling of the UK's National Centre of Excellence for Composting. The site, which has a Waste Management Licence and planning permission to process more than 100,000 tonnes of organic waste a year, is already home to a major contract.

The Composting Research Project involves the composting of organics fines to produce a range of materials, which will then be used in sites across the UK to determine their potential future use in soil restoration, biofuel production and agriculture. This trialling section will form a major part of the project, which was funded by landfill tax credits through WREN, the environmental arm of the waste management company Waste Recycling Group.

The Centre also received a further major boost in September when ADAS was awarded preferred bidder status for a £2.4 million project funded through Defra's New Technologies Demonstration Programme, which will use state-of-the-art batch tunnels to optimise the composting process in terms of energy consumption, labour costs and process time. The project will also identify, quantify, and develop procedures to minimise, emissions from the composting process such as bioaerosols, VOCs and odours.

COMPOST AS A DE-CONTAMINATE Although these are early days for the centre, it is currently involved in many projects designed to provide new and improved solutions in this area of expertise. One such project evaluated composting as a method for the removal of contamination from road sweepings.

The twelve-month project took place at a commercial facility in Worcestershire which composts green waste and accepts road sweepings and gulley cleanings for landfill. A sample of the road sweepings was composted with various amounts of green waste material over a prolonged period with analysis undertaken to determine the rate at which contamination with hydrocarbons decreased as composting progressed.

Designed to discover whether contamination could be removed from road sweepings, the project would result in major savings in landfill void space if successful. This could potentially extend the beneficial use of the material rather than simply landfilling.

The project's findings demonstrated that there are various advantages of composting this material and the levels of contamination of road sweepings were found to be generally low but variable. It was also interesting to note that some of the analyses for the untreated road sweepings confirmed that the material could potentially comply with the British standard for top soil.

TREES TO PAPER, PAPER TO TREES Another project, looking at developing methods of composting waste paper packaging, has also recently concluded. The project sought to take waste paper that could not be recycled conventionally, such as laminated card and highly printed card and paper, and develop it into a product that could be used as a mulch or soil improver. The new material is then used to establish areas of trees, thus completing the cycle - trees to paper and paper to trees.

The research showed that post-consumer packaging waste can be successfully composted, using bio-solids as a co-constituent, to produce an acceptable product for use in land remediation and soil amelioration. This process can divert non-recyclable residual packaging waste from landfill and could therefore assist local authorities and the waste management industry to meet recycling targets.

Positive benefits of composting post-consumer paper based packaging wastes include the fact that it diverts organic materials from landfill or incineration and it enables the recovery and recycling of packaging material. Recycling percentages are improved and the end product can be used as a soil improver for use in land remediation, landscaping and forestry

. The research into this composting solution has proved so successful that ADAS has produced a users manual as a guide to this process to communicate the lessons learned and share best practice.

FOOD, FISH AND FURTHER Composting research and development for fish waste is also an important area in which the organisation has been involved, and which came about as a result of several factors. The Government recently brought in various regulation and economic instruments such as the Landfill Tax in order to discentivise the landfilling of waste, in particular biodegradable waste from sectors such as the food industry.

Meanwhile, animal disease outbreaks have brought bio-security issues to the fore and this focus has now been formalised by the Animal By-Product Regulations 2003 (ABPR2003). The ABPR2003 brings significant new controls to the food industry and includes seafood waste. One control outlaws the direct landfilling of seafood waste and another requires various minimum standards of treatment if the food waste is to be recovered as fertilizer for use on land.

In light of these new requirements of the seafood industry, ADAS has been conducting research that focuses on high temperature composting and follows a range of mixes of seafood waste with household green waste, such as grass clippings, through the composting process.

The main seafood waste types used were mackerel, white-fish and shellfish and these were studied as four treatments, with each tested separately and one for a complete mix of all of the fish types. Observations were made daily and samples were taken at intervals.

The outcome of this project gives reassurance that seafood-based composted materials can provide useful soil-conditioning and nutrient-adding properties for agricultural land, including reclamation and forestry areas.

With an ever-increasing number of regulations being introduced with regards to the management of waste and a movement away from the use of landfills, composting as a means to reduce and treat waste is becoming more and more important. As research and development into this area continues apace, composting is sure to be used to treat a greater variety of waste products and on a more extensive basis in the future.

ADAS provides solutions and policy advice on rural business and environmental issues. For more information visit: http://www.adas.co.uk/home/


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