As you can imagine, a great deal of work has already been done at The Avenue. Below, you’ll find a brief overview of what we’ve done so far, listed in date order, starting with our most recent news:
Low Temperature Thermal Desorption by Rotary Kiln Trial
This involved putting contaminated sediment and soil from The Avenue through a kiln, at temperatures between 450 and 600°C. It removes contaminants such as Poly-aromatic hydrocarbons (PAHs) and cyanides. The heat turns the contaminants from solids to gases which are collected and treated to make them safe in a complex process that is well tried and tested by emda’s project delivery partner DEC in the Netherlands. The soil comes out of the process hot but very clean. It can then be re-used anywhere in the site.
Batch Thermal Treatment Trial
In autumn 2003, project partner MEL Ltd brought a mobile thermal treatment plant to The Avenue. This was used to treat and clean contaminated soil and sediment. The plant works by heating soil to temperatures of 285°C, driving off contaminants by turning them into gases that can be safely disposed of.
Dewatering of Lagoon Material Trial
Also in autumn 2003, project partner Onyx, trialed dewatering technology at The Avenue – to reduce the amount of sediment on the site. This involved pumping lagoon sediments and using centrifuge technology to remove water from the sediment, leaving the solid part of the sediment behind.
Chemical Plant Clean-Up
We finished cleaning the chemical plant at The Avenue in early 2003. Onyx, one of the UK’s leading waste management companies, carried out the work. The last phase of the clean-up involved removing tar waste from the chemical plant and treating contaminated rainwater so we could dispose of it safely.
Demolition of the Coal Charging Bunker
The Avenue’s ‘landmark’ Coal Charging Bunker was demolished in February 2003, watched by a crowd of over 600 people. The bunker weighed 5,000 tonnes and was 45 metres high. It was demolished by Detech Environmental Ltd and Controlled Demolitions using explosives. Once the bunker was demolished the waste concrete was pulverized using hydraulic machines and will be re-used on the site.
Investigation of Lagoon 2
In January 2002, we had one of the most hazardous parts of The Avenue examined – the waste lagoon. Gardline Surveys carried out the survey which involved using a lightweight pontoon to reach the middle of the lagoon, and a hollow steel tube with a plastic liner (known as a vibrocore) to take a sample of lagoon water and sediment. Because the lagoon was contaminated, the crew had to wear full protective clothing.
Soil Cleaning Trials
We’ve always been committed to making sure we regenerate The Avenue in an environmentally sustainable way. That’s why in 2001, we invited companies from all over Europe to demonstrate the technologies they could offer The Avenue. After extensive tests, the following methods were chosen to help clean up the site.
Bioremediation – a process whereby microorganisms are encouraged to thrive in the soil and literally eat any contamination.
Soil washing – works by mixing soil with water in the equivalent of a large washing machine. The friction between the soil particles and the machine releases the contaminants which can then be filtered and disposed of safely.
Thermal Desorption – involves heating contaminated soil to temperatures of up to 400°C, to drive off any oil-based contaminants.
Lagoon Stabilisation
Back in 2000, we strengthened the embankment around the waste lagoon to stop any pollution of the river nearby. Special instruments were built into the embankment to relay information to our team of engineers. In addition, all the soil used to construct the embankment was taken from locations around The Avenue. Eventually, the whole area will be fully cleaned.
Fencing
At the beginning of the project, we replaced the perimeter fence around The Avenue to help keep the public safe and prevent trespassers. We also have full-time security staff on duty at the site.
Asbestos Removal
Although most of the asbestos at The Avenue was removed when the buildings were demolished, we carried out a survey of the site to see what asbestos remained. This was then removed and safely disposed of.
Site investigation
Before the clean-up began, we carried out a thorough survey of the site, including taking soil samples and testing for potential pollutants.. As you can imagine, the results played a key part in deciding how best to clean-up The Avenue.
Chemical Plant Demolition Works
From May 1999 to June 2000, project partner Detech Environmental removed numerous pipelines and supporting structures from The Avenue’s former chemical plant. They were highly corroded too, so it took a lot of skill and experience to remove them safely. Before they could be removed, most of the pipes had to be cleaned by waste management specialist, Onyx – to remove any remaining chemical residues. In addition, the plant’s major concrete structures such as the cooling towers were removed, mostly using explosives.
Site Clearance Works
Before the remediation phase of the project began, The Avenue team installed fences around the site to protect the existing animal population. We also carefully captured the great crested newts and grass snakes and relocated them to safe, alternative habitats away from the remediation works.
Reclamation of the Rail Sidings
In January 2005, we reclaimed and re-landscaped the former rail sidings at The Avenue. Coal was transported to The Avenue coking works via rail, which is why there were rail sidings at the site. The area has been transformed into a public bridleway suitable for pedestrians, cyclists, horse riders and wheelchair users. There are also parking areas and pastures used by grazing cattle and sheep. In addition, we also re-developed the River Rother and the Redleadmill Brook to create a wetland habitat for water voles and other aquatic wildlife. The Avenue Washlands Nature Reserve officially opened on Friday 3rd August 2007.
Water Treatment Works
Early on in the project we decided to build our own water treatment plant; to treat contaminated water from The Avenue. Treating the water on-site is safer and more cost-effective than taking the water to a waste treatment facility. The water treatment plant is designed to use both physical and chemical treatment methods to remove metals, destroy pollutants such as cyanides and filter out harmful chemicals commonly found in tars and creosote. Once treated, the water flows through a weir where the flow rate is monitored and samples are collected automatically by a sampling device. These samples are then analysed twice a week to make sure the water treatment works are working properly. Samples are also tested independently by Yorkshire Water.
