Advances in technology spearhead composting drive

Composting remains a key plank in achieving the national targets for the minimisation of waste and recycling as local authorities and the waste management services sector raise the level of facilities across the country. In this special feature LAWE reviews current developments including a new aid to the selection of in-vessel composting equipment

Marking this year's Compost Awareness Week 2004, The Composting Association has published *A Guide to In-Vessel Composting: plus a Directory of System Suppliers. Written and designed to inform the decision making process, the publication provides a valuable insight into in-vessel composting processes and provides a wide-ranging directory of technologies available in the UK.

The association says that the guide has been published in response to demand from all sectors of the waste management industry and has been personally welcomed by the Minister of State for Environment and Agri-Environment.

Elliot Morley said: "Government recognises the important role composting plays in achieving these targets and also in developing a soil strategy and welcomes the technological advances that have been made in composting, not least in response to the Animal By-Product Regulations.

"Local authorities and compost producers now have a variety of composting systems to choose from and all members in the industry need to keep up to date with developing technologies. The timely update of this guide will provide a valuable resource for those considering the 'in-vessel route'."

The guide briefly introduces the topic of in-vessel composting and reviews the drivers for increased composting. Two practical chapters follow, describing the types and the management of in-vessel systems including Hazard Analysis and Critical Control Point (HACCP) assessment. One of the key drivers for this guide is the Animal By-products Regulation, and the veterinary approval process is briefly described.

The main section of the guide is devoted to the technical and operating details of over 30 different in-vessel systems. These range in size from those suitable for a small community to large Mechanical and Biological Treatment (MBT) facilities. Photographs of each system allow readers to gain an impression of the size of the unit and its likely visual impact.

Compostable bag

On the products front, compostable bag manufacturer, Ecosac Ltd, has become the first company to gain certification for its products through the compostable packaging certification scheme run by The Composting Association and German certification body, Din Certco.

Launched in December at The Composting Association's Annual Conference, the new certification scheme is the first of its kind in the UK. Products must undergo stringent testing and meet the appropriate European Quality Standard (EN 13432) before being certified as compostable. To achieve certification, materials and additives are tested for heavy metals, complete biodegradation, disintegration under standard composting conditions and toxicity to plants.

Shropshire-based Ecosac Ltd. has achieved this standard for its Ecosac range of products, using materials made from high-quality impurity-free maize. Frazer Walker, Director of Ecosac Ltd, said: "This certification is a milestone not only for us as a producer of compostable packaging but for the industry as a whole. Local authorities and composting companies need to know that bags and other packaging products used in their green waste and catering wastes collections will biodegrade within their operating cycles. They must also be certain that the material will completely disappear and leave no contamination causing residues." Chief Executive of The Composting Association, Dr Jane Gilbert, welcoming the award, said "This award is an important step forward for the composting industry. Now, with the ability to specify bags made to this standard for collecting green and catering wastes, composters and local authorities alike can be assured that the quality of their finished composts will not be affected."

A number of local authorities and composters are already using Ecosac's compostable bags. Monmouthshire County Council has been using the 75 litre bags since it launched its organics kerbside collection scheme last July. The council collects co-mingled green waste, paper and cardboard from 30,000 households per week and has seen its recycling rates rise dramatically as a result.

Paul Quayle, Waste Strategy Officer for Monmouthshire, said, "Since the introduction of the scheme last summer we have been overwhelmed with its popularity amongst our community. We have already taken delivery of over one million bags and collected 1,500 tonnes for on-farm composting - waste which otherwise would have gone to landfill."

Ecosac was also the preferred collection receptacle for Brentwood District Council's green waste kerbside collection service. Once collected, the bags are taken to Cleanaway's composting facility at Pitsea, Essex, for composting. Compost Development Manager at Cleanaway, David Nicholson, praised the bags saying "We are extremely pleased with the performance of these bags, they have broken down rapidly within six weeks of entering the Pitsea facility - leaving no detectable traces in the finished compost. We have no hesitation in accepting starch bags like these made from Mater-Bi starch and have asked the districts purchasing compostable sacks for green waste collections to specify that the sacks be registered to the Composting Association's biodegradable bag scheme wherever possible."

New home composters

Straight plc has extended its home composting range, introducing two Compost Machines with a capacity of 235 litres and 335 litres. Both are bigger and more durable than their predecessors, with a number of improved features. Available in black or green and with a removable side hatch, the Compost Machines are moulded from 100% UK post-consumer recycled plastic and guaranteed for 15 years. Lids are twist on, lock into place with a windproof fit and incorporate moulded guidelines on which materials may be composted.

Straight is also adding new larger flat-packed bins, wooded composters and worm bins to its range for 2004, as well as a host of new accessories. Announcing the new products, the AIM listed supplier of recycling containers has also unveiled plans for a £100,000 fund to help local authorities promote home composting and water conservation.

One company participating in the scheme is Thames Water Utilities, who will promote the home composting and water conservation message through Straight to more than one million homes in London and the Thames Valley Region.

Shredder for amenity sites

Composting machinery specialist MENART has developed a green waste shredding installation for use at community amenity sites. A client's problem of inefficient collecting and transporting of high volumes of green waste resulted in the use of too many containers each week and inefficient compaction of container loads. The solution was to shred on site with the local residents depositing their green waste into the shredder hopper themselves. The installation is built around a MENART P-115-ME Shredder mounted on a permanent fixed chassis with the collection containers placed in a tunnel under the machine, which has a 6m3 hopper. The shredder is activated safely by a site supervisor.

*A Guide to In-Vessel Composting - Plus a Directory of System Suppliers has been published with the support of DEFRA through the Environmental Action Fund and is available from The Composting Association on 0870 160 3270 and can also be ordered through



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