20 July 2015

by Steve Eminton

Andigestion’s new £10 million anaerobic digestion facility in Cheltenham opened last week with a warning from the company’s chairman that Britain’s renewable energy policy “is in chaos”.

Chairman, Peter Prior, said: “Renewable energy policy is in chaos and is not delivering the cheapest or best buck for the taxpayers. This needs to be reviewed – one of the problems of renewable policy is that it is so complex.”

Mr Prior explained that the new facility, on the Wing Farm waste site in Bishop’s Cleeve, a few miles north west of Cheltenham, has seen a £10 million cash investment by the company which is a subsidiary of his family gravel business, Summerleaze.

And, Mr Prior emphasised that Andigestion had not needed to go to banks to borrow to fund the development which is built on land owned by Grundon. It sees gas from the AD process cleaned up and injected into the grid. Digestate will be spread on local farms and this will be organised by 4R Recycling.

Gloucestershire

The plant has an annual capacity of 32,000 tonnes of food waste and about 10,000 tonnes will be coming to it under a long-term local authority contract with Gloucestershire county council. The local authority input is due to increase as more councils in the area start food waste collections, including Stroud next year. Before the development of the site, food waste from Gloucestershire was going to Rose Hill Recycling’s IVC site in Dymock.

Other material for Bishop’s Cleeve will come from commercial sources and Grundon will be one of the waste companies bringing food waste in.

Bradley Smith, sales and marketing director at Grundon, told letsrecycle.com that the company was offering a “dedicated food waste collection service throughout Gloucestershire and the Cotswolds for commercial customers”. He added that Grundon is providing 120 litre wheeled bins which are designed to fit under the counter in food preparation areas.

Environment

The Andigestion plant was officially opened by farmer and BBC Countryfile presenter, Adam Henson who said “the key to all this is in the environment”.

After explaining how on his farm the environment is very important, through planting wildlife strips, feeding the birds and carefully managing inputs and fuels, Mr Henson emphasised the importance of relationships between all those involved whether on a farm or on a project such the Andigestion plan.

“On the farm it is also about the relationships of the people you work with,” he said. “This includes the council, the people who consume the food, suppliers, all those types of people, and I believe these relationships, and recognition of how important they are, are coming back. We have a responsibility, a social responsibility and honesty and integrity has to be part of our values. But, of course we recognise that while we want to achieve sustainability you do also have to make money.”

Technologies

The Bishops Cleeve plant brings together a number of innovative and new technologies into the AD process.

Chairman Mr Prior said: “This site has been designed by us pulling bits together from other people, we are almost an engineering company now.” And he highlighted how Andigestion was one of the pioneers of AD in the UK having “got into AD in 2003. Our main plant is in Holsworthy in Devon where we are generating electricity and trying to find ways for using the heat.”

Biogas

A £2.3million Malmberg biomethane plant is the centrepiece and its design is said to be the first of its size to be installed anywhere in the world. The GR BAS 3 machine is sized to deal with up to 550 Nm3/hr of biogas. By incorporating a pre-treatment (booster and chiller) phase to maximise the capacity, Malmberg has increased the biogas capacity from 550 Nm³/hr to 650 Nm³/hr.

The process is, explains Andigestion, fully intuitive and the performance parameters adjust automatically to variations in flow and biogas quality. “As a result, the plant recovers more than 99% of the methane from the incoming raw biogas. The process requires no heat or chemicals, it uses only potable water and power – and the machine operations can be monitored and controlled remotely via internet connection.

The digester tank design is completely new to the industry. It is made up of concrete segments and the external walkway and dome section on top of the tanks facilitates safe and easy access for maintenance to the mixers and the domes. The tanks were designed and provided by A Consult based on the requirements of peripheral access.”

Carrier bags

The public are allowed to put their food waste into plastic carrier bags and this material is handled by the depackaging equipment from Rowan Engineering. It involves three DM3000 ‘Dominators’ with two primary ‘Dominators’ feeding a secondary unit. The system was designed specifically for Andigestion to deal with source separated food waste. The ‘Dominators’ are a 3m long hammer mill design. The innovative part is the use of the third ‘Dominator’ to clean up the rejected packaging from the first two, leading to a clean output, suitable for recycling.

The odour control plant was supplied by ATS. The design aim was to minimise air changes – at the same time as maintaining odour control by utilising jet flow and directional flow nozzles to concentrate the odours in areas where maximum extraction takes place. The neutralising media is wood chip from Italy and Germany.

Wheelie bins

As part of its waste collection business, Andigestion has launched a wheelie bin exchange service. The 240 litre bins are micro chipped. MOBA provided software means tracking and invoicing can be automatic – and managed remotely.

At the plant, a cost effective wheelie bin emptying system has been procured from Challenger Engineering. This includes a dynamic weighing system, so weights for each individual bin can be recorded and reported to customers – who require information on the waste tonnages they are diverting from landfill.

Related links

Andigestion

Gloucesterhire