PIERCING changeable skies and withstanding inclement conditions, it once stood like a beacon, a dominant structure overshadowing its environment with ease.

A real sign of strength, it was symbolic of an ongoing revolution in North-East energy production.

The looming figure, a crane, has now long gone, its red and white-coloured components removed with military precision by a team of engineers.

But the legacy it has left behind now stands to reach even greater heights.

From its small foundations, dug just months ago, an £8m plant that will convert food waste into energy and a separate bio-fertilser now holds the commanding presence on Newton Aycliffe Industrial Estate, in County Durham, its tall digester replacing the crane on the horizon.

The Emerald Biogas anaerobic digestion factory is the North-East's first commercial food-to-waste factory, and will create eight jobs when finished.

Bosses hope to start work in July, and when working at full capacity, the plant will initially convert 50,000 tonnes of food waste from across the region every year into heat and power.

Producing 1.56 megawatts, which is enough to power about 2,000 homes, the firm will separate packaging, such as glass and plastic, from waste, before turning it into electricity that will be pumped into the National Grid, with further scope to provide heat for neighbouring businesses.

And proposals are already in place for a second phase development, backed by the security of a number of food waste contracts, including the potential to upgrade the biogas to a higher-grade product that can be injected into the gas grid, and a vehicle fuel station.

Formed in 2009, Emerald Biogas is run by Adam and Antony Warren, owners of the John Warren ABP food waste collection and animal by-product recycling firm, and Ian Bainbridge, who runs Agricore, who cannot wait for the operation to begin.

The region may finally be shrugging off the lingering depression of winter's icy grip, and that sense of optimism is overtly present as you walk around the site.

This unswerving optimism and vibrancy, which is still abound despite the battles against heavy rain, snow and high winds, is reflected through the workers, who continue to busily flesh out the factory's inside.

Blue hues emanate from the corner of the building, as an engineer welds pipes into position, while in another, a painter works on components.

Outside, more pipes are manoeuvred into place, as steel mesh sits fixed in position, awaiting a delivery of concrete, and a second crane dismantles the arm of its predecessor.

Everything is coming together.

Sitting in a portable site office, as the changing weather continues to torment with its mix of sunshine and heavy rain, Mr Warren says they cannot wait to get started.

He said: “We have come through some severe weather this winter to work on the plant, it has been difficult at times, and there have been times where we have seen some of the worst weather for years, but we are getting there.

“Security is one of the most important things for customers and quite often when waste processes are started, they are fraught with difficulties.

“There are problems with letting down customers and also struggling to get materials, which leads to a bottleneck.

“However, we have all of those issues covered.

“Ian will take the digestate and the National Grid is not going to let us down either.

“We have contingencies in place to avert any problems with waste coming into the plant, that will be solved without anyone knowing, and that reflects the strength of our partnership.

“We have extensive experience in waste management at John Warren, and always ensure we have a number of outlets for the waste we collect.

“While we plan to divert all of the waste to Emerald, we can call upon a number of none landfill alternatives should there be a problem at our facility.

“It is this knowledge and network of infrastructure which provides added reassurance to our customers that we are able to manage their waste effectively and will not have to rely upon landfill at any time.”

Mr Bainbridge says the bio-fertiliser, which will include nutrients such as nitrogen, phosphate and potash, will be supplied to landowners and agricultural businesses within 10 miles of the site, representing the plant's additional benefits.

He said: “Once the anaerobic digestion process is complete, we can be completely confident that the by-products of energy and fertiliser will be used effectively.

“We know the the power will eventually be supplied to local business, but Agricore also has access to a land bank that can accept the 50,000 tonnes of digestate produced annually.

“This approach sets us apart from our competitors and will ensure we are the leading anaerobic digestion facility in the North-East.”

WHAT IS ANAEROBIC DIGESTION? Operating between 35°C and 40°C, the process takes place in a sealed and insulated vessel with controlled heating and mixing.

Commercial food waste is gathered from manufacturers, restaurants, cafes, shops and local authorities, and moved to a sealed building to be de-packaged, blended and pasteurised, and pumped into buffer tanks.

The waste is later pumped into a digester, where bacteria feed on the food waste and produce biogas.

Anaerobic digestion is made up of four bacterial processes:

Hydrolysis - Large molecules of carbohydrates, fats and protein are broken down to small water-soluble particles. These are simple sugars, lipids and amino acids, and are now ready for the bacteria within the digester.

Acidogenesis - The products of hydrolysis are converted into volatile fatty acids (VFA) by bacteria, and are short- chained organic acid molecules, with the most important being acetic acid.

Acetogenesis – The VFAs are converted to acetic acid by bacteria.

Methanogenesis - Where the methane is made. Acetic acid is used by methane forming bacteria, and the majority of the methane in biogas is produced in this manner.

During this continuous process, which lasts approximately six weeks, no methane is released into the atmosphere.

The biogas produced is typically made up of 60 per cent methane and 40 per cent carbon dioxide and is captured and used as a fuel in a combined heat and power unit.

The resultant liquid digestate, having had the majority of the organic material digested, is odour free and stored in large covered tanks before being delivered to agricultural businesses within a 15-mile radius of the site.

The use of this high nutrient biofertiliser replaces the use of fossil fuel derived fertiliser and ensures nothing is wasted from the entire food waste process.