CASE STUDY
F M Conway's Dartford Aggregate Reprocessing and Drainage Treatment Facility
Feedstock
Concrete and asphalt: 150,000 tonnes/yearGully waste: 30,000 tonnes/year
Outputs
Washed and graded aggregate: 100,000 tonnes/yearUnbound mixtures: 40,000 tonnes/year
Cold recycled bitumen bound material (Foamway): 10,000 tonnes/year
Disposal/recycling of gully waste arisings: 30,000 tonnes/year
Disposal/recycling of gully waste arisings: 30,000 tonnes/year
Date
2004, ongoing
Location
Location
Dartford, Kent
Overview
Every year enormous quantities of highway maintenance and gully waste arisings are produced as a result of ongoing maintenance of the trunk and local road networks. The arisings from these works are often recycled at a relatively low level, as unbound granular materials or, in the case of gully waste, disposed of to landfill. This does not represent the most sustainable use of these materials, as they have the potential for use in higher value applications. However, these low value end uses are often justified on the basis that it is too expensive to invest in the processing plant necessary to produce the high value products.
F.M. Conway are a major civil engineering company specialising in term maintenance contracts for highway maintenance for London Boroughs and County Councils in the South East. They produce large quantities of concrete, asphalt, soil and gully waste as part of their operations. As a forward-thinking company, they were aware of the shortage of natural aggregates in the South East, the increasing use of recycled aggregates, the development of national specifications that permit the use of recycled aggregates in high value applications such as asphalt and concrete, and likely future difficulties in disposing of gully waste and other materials to landfill. They therefore decided to invest in a comprehensive package of treatment plants to produce high value products.
F.M. Conway examined best practice technology and systems in the UK, America and Europe and worked with plant manufacturers to develop a bespoke package of measures for their depot in Dartford, Kent. This included an aggregate washing plant, a drainage treatment plant using advanced water treatment technology, a plant for production of cold recycled bitumen bound material and a fleet of volumetric mobile concrete batching vehicles as well as crushers and screeners. Nearly all the systems are computer controlled, and all operate under specifically designed quality control systems. This represented a considerable investment of money and time to assemble the various components and amalgamate them into a compatible system. The result is a state-of-the-art system that handles all F.M. Conway’s material streams, utilises synergies between the different plant systems and maximises the production of high value, quality controlled materials.
The case study illustrates that investment in advanced technology, such as the aggregate washing plant and drainage treatment plant, can be cost effective by enabling use of recycled aggregates for high value end uses such as recycled aggregate concrete and cold recycled bitumen bound material. The investment is worth while for F.M. Conway because they have a large and reliable stream of suitable incoming material – about 150,000 tonnes per year of concrete and asphalt – from their own highway maintenance contracts with London Boroughs. They also have a reliable market for the high value products through these same contracts. This base load is augmented by obtaining suitable construction and demolition materials from the local area and by sales of concrete and other products to the market. The market for recycled aggregates is particularly well developed in the London area, but similar operations should be viable around other large urban areas such as Birmingham. They may be less viable in the short term where high quality natural aggregates are available at low prices.
The investment in time and money to set up a system such as that described here should not be underestimated. It has taken F.M. Conway most of 2004 to obtain the equipment, set it up and get it running at maximum efficiency. The investment is a long term one, which is enabled in their case by long term highway maintenance contracts with London Boroughs. The results demonstrate that this investment is good business sense that enables F.M. Conway to maximise the value of their arisings and places the firm in a good position to address future challenges.
For a full version of this case study click here![[pdf]](/display_images/document_icons/pdf.gif)
Contact Details
F.M. Conway Ltd,
Andrew Holmes,
Conway House,
Rochester Way,
Dartford,
Kent.
DA1 3QY
Tel: (020) 8636 8822
Fax: (020) 8636 8827
Email: andrew.holmes@fmconway.co.uk
Website: www.fmconway.co.uk
Overview
Every year enormous quantities of highway maintenance and gully waste arisings are produced as a result of ongoing maintenance of the trunk and local road networks. The arisings from these works are often recycled at a relatively low level, as unbound granular materials or, in the case of gully waste, disposed of to landfill. This does not represent the most sustainable use of these materials, as they have the potential for use in higher value applications. However, these low value end uses are often justified on the basis that it is too expensive to invest in the processing plant necessary to produce the high value products.
F.M. Conway are a major civil engineering company specialising in term maintenance contracts for highway maintenance for London Boroughs and County Councils in the South East. They produce large quantities of concrete, asphalt, soil and gully waste as part of their operations. As a forward-thinking company, they were aware of the shortage of natural aggregates in the South East, the increasing use of recycled aggregates, the development of national specifications that permit the use of recycled aggregates in high value applications such as asphalt and concrete, and likely future difficulties in disposing of gully waste and other materials to landfill. They therefore decided to invest in a comprehensive package of treatment plants to produce high value products.
F.M. Conway examined best practice technology and systems in the UK, America and Europe and worked with plant manufacturers to develop a bespoke package of measures for their depot in Dartford, Kent. This included an aggregate washing plant, a drainage treatment plant using advanced water treatment technology, a plant for production of cold recycled bitumen bound material and a fleet of volumetric mobile concrete batching vehicles as well as crushers and screeners. Nearly all the systems are computer controlled, and all operate under specifically designed quality control systems. This represented a considerable investment of money and time to assemble the various components and amalgamate them into a compatible system. The result is a state-of-the-art system that handles all F.M. Conway’s material streams, utilises synergies between the different plant systems and maximises the production of high value, quality controlled materials.
The case study illustrates that investment in advanced technology, such as the aggregate washing plant and drainage treatment plant, can be cost effective by enabling use of recycled aggregates for high value end uses such as recycled aggregate concrete and cold recycled bitumen bound material. The investment is worth while for F.M. Conway because they have a large and reliable stream of suitable incoming material – about 150,000 tonnes per year of concrete and asphalt – from their own highway maintenance contracts with London Boroughs. They also have a reliable market for the high value products through these same contracts. This base load is augmented by obtaining suitable construction and demolition materials from the local area and by sales of concrete and other products to the market. The market for recycled aggregates is particularly well developed in the London area, but similar operations should be viable around other large urban areas such as Birmingham. They may be less viable in the short term where high quality natural aggregates are available at low prices.
The investment in time and money to set up a system such as that described here should not be underestimated. It has taken F.M. Conway most of 2004 to obtain the equipment, set it up and get it running at maximum efficiency. The investment is a long term one, which is enabled in their case by long term highway maintenance contracts with London Boroughs. The results demonstrate that this investment is good business sense that enables F.M. Conway to maximise the value of their arisings and places the firm in a good position to address future challenges.
For a full version of this case study click here
Contact Details
F.M. Conway Ltd,
Andrew Holmes,
Conway House,
Rochester Way,
Dartford,
Kent.
DA1 3QY
Tel: (020) 8636 8822
Fax: (020) 8636 8827
Email: andrew.holmes@fmconway.co.uk
Website: www.fmconway.co.uk
