Major C&D waste recycling plant for Nick Brookes Group

• 
• 19th March 2009
• Recycling
 

One of the leading recycling companies in the North West of England has recently demonstrated an ongoing commitment to continuous improvement by installing a new state of the art washing plant. The Nick Brookes Group, based in Cheshire is now running a 120 ton per hour C&D waste recycling plant.

The Nick Brookes Group is one of the most prominent recycling companies in the region and have decades of experience in the waste, recycling and demolition sectors counting several leading house builders and local authorities among their customers. Their extensive recycling operation opened at its current location in 2005 and processes the full range of materials including metals, wood, paper & cardboard, green waste, plastics and construction and demolition waste material.

The new washing plant from CDE was purchased to improve the handling of the construction and demolition waste material that is received at the site, which can be found just off the A51 near Nantwich.

"We made the decision to install the CDE plant as we wanted to improve the quality of the final products we were able to produce from the construction and demolition waste that we take in" explains Nick.

Essential Experience

Over the last 10 years CDE's network of plants has expanded as demand for recycled aggregates continues to grow.

"In the last number of years we have installed a large number of aggregate recycling plants throughout the country," explains CDE's general manager in the UK, Terry Ashby. "Nick Brookes plant is one of four that we have completed since the beginning of the year and there are currently another three projects in progress."

As with any construction and demolition waste recycling plant, the primary consideration in the design stage is the highly variable feed material. This problem is further accentuated by the fact that unlike a traditional quarry operation, there is not ready availability of the feed material for testing. With this in mind, the selection of a supplier with extensive experience in this sector was something that Nick Brookes was very keen to ensure.

The construction and demolition waste recycling plants installed by CDE operate a tried and tested model that has been used extensively over the last number of years. However, one of the main advantages of the CDE plant is the high level of customisation involved on each installation.

The processing system

The installation at Nick Brookes Group site starts with an integrated hopper and conveyor at the beginning of the processing operation, which feeds the first of several screens from CDE's ProGrade range that can be found on this project. In addition there is a RotoMax logwasher and an EvoWash sand plant. This plant also includes a full water treatment phase with an AquaCycle Thickener and Overhead Beam Filter Press, ensuring that the plant produces no waste material at all. The filter cakes produced by the press can be used as landfill capping or canal lining, thus massively reducing the environmental impact of the operation. This is an element of the plant that Nick Brookes was determined to incorporate as the company has built a reputation for leading the way in the recycling market in recent years.

"Since we opened our new facility in 2005, we have worked very hard to ensure that the maximum amount of material that we take in is recovered for use in some shape or form" explains Nick. "At present our recovery rate sits at around 90%. This puts us right at the head of the industry and we are determined to further improve this."

The full plant at Nick Brookes site is a very compact operation and the inclusion of a full water treatment phase was essential given the location in an industrial area. The feed material is loaded into CDE's specially designed recycling hopper with its integrated 22 m feed conveyor. The focus on efficiency begins at the very outset of the CDE plant with the hopper and conveyor integration. The integrated belt feeder mechanism within the hopper ensures the transfer of material to the 22 m conveyor occurs as efficiently as possible by minimising spillage. There are also skirting rubbers around the entire base of the hopper, again minimising spillage.

Transfer Point Technology

"All the transfer points between individual pieces of equipment are carefully considered and we design to ensure that all individual components integrate together in the most efficient way possible" explains Brian McCullough, CDE's design manager. "The ultimate result of this is a plant that delivers the highest possible volume of high quality material."

The 22 m feed conveyor has an overband magnet fitted to remove any ferrous material from the feed. The next stage in the process sees the introduction of one of CDE's ProGrade rinsing screens. The specific model on this project is a two-deck 4 x 1.5 m screen. The -5 mm material is removed at this point and sent to the EvoWash sand plant for further treatment. Meanwhile, the +5 mm material is sent to the RotoMax log washer. This machine has developed a reputation for its ability to effectively clean very dirty or clay bound material in traditional quarry operations. The model used on this recycling project is their RX150 model, which has been specifically designed for recycling operations.

"There are some differences between the Rotomax that we will supply to traditional quarry operations and that which we specify on a recycling project" explains Brian McCullough. "This is a result of the need to remove organic materials such as wood, plastic and polystyrene from C&D waste - something that you would not usually encounter in a quarrying operation."

All of the organic material in the C&D waste feed is floated off the rear of the Rotomax to a trash screen, and is then discharged into a bay. Likewise, any remaining -5 mm material flows to the EvoWash sand plant while the +5 mm material is discharged from the Rotomax onto another ProGrade dewatering screen.

The next stage in the process sees the introduction of a non-ferrous separator prior to the +5 mm material being sent to a final sizing screen. The non-ferrous separator discharges the material into a skip and the remaining aggregates are sent to another of CDE's ProGrade range - the particular model used here is a two-deck 5 x 1.5 m screen. This screen has a split bottom deck and produces 4 products - +40 mm, +20 mm, +10 mm and 5-10 mm.

The EvoWash sand plant on this project is a dual sand model, producing both a fine and coarse sand.

Full water treatment

Following the sand washing phase of the project the waste water from the sand plant is then sent to an AquaCycle A400 thickener for the first phase of the water treatment process. Upon entry into the Thickener the material is mixed with a small amount of flocculent prepared in the integrated Polyelectrolyte Dosing Station. The material then enters into the Thickener tank were it quickly begins to form a thick sludge and settle to the bottom of the tank. The clean water overflows the top of the tank and is sent to an AquaStore tank for re-circulation around the system. Meanwhile a set of rakes rotate along the bottom of the tank moving the sludge into the centre and preventing the sludge from setting. The rakes also send information about the amount of resistance back to the central PLC control panel, which automatically starts and stops the main sludge pump when required. The thickened sludge is then sent to a buffer tank for further treatment by the GHT Filter Press.

The Overhead Beam Filter Press is a heavy duty machine specifically designed for the quarrying industry successfully eliminating the problems associated with commonly found side-bar designs. The GHT is capable of 24 hour unmanned operation and is famed for the dry, easily handled waste it produces without having to use any additional chemical or flocculent.

"We are finding an increasing number of our projects in both the traditional quarrying and recycling sectors are incorporating filter presses," says Enda Ivanoff, CDE's sales director. "This is undoubtedly a result of an increasing focus on reducing the environmental impact of washing operations and is something that we expect to continue in the coming months and years."

Certified Sand and Aggregates

The specification of a recycling plant that can deliver certified sand and aggregates is essential if the industry is to continue to prosper. This remains a strong growth area within the UK industry as a result of the growing demand for recycled products. However, if this demand is to continue to grow, it is essential that all who work in the industry take heed of the recent warnings delivered by WRAP concerning so called ‘recycling' operations currently produce material that does not comply with the required specifications for use.

"As further research is conducted into the various properties and performance characteristics of recycled sand and aggregates, the list of potential applications is consistently growing" says Brian McCullough. "If demand for this type of material is to continue to grow it is essential that the recycling plants specified are capable of producing the material to the required specification. As with natural sand and aggregates, certain standards need to be met and our plants are designed to ensure that the final products meet and exceed these standards"

The UK industry is a world leader in terms of the quantity of recycled materials that are produced and there is strong evidence that there is plenty of growth yet to be enjoyed. A continued focus on the delivery of high performance plants such as those offered by CDE will ensure that the industry continues to develop into a major force.

"Our recycling plants have evolved considerably over the 10 years that we have been working in this area" concludes Enda Ivanoff. "We pride ourselves on this culture of continuous improvement and can assure all our customers that we will continue to develop our expertise to ensure performance remains at an optimum level"

Plant provides high quality sand

Enda Ivanoff, CDE's sales director who retains extensive involvement in all of the company's product development initiatives reveals that there are number of design features of the EvoWash range which offer tangible benefits for CDE's customers. The first of these is ensuring the achievement of consistently accurate silt cut points at 63 micron.

"There are numerous plants out there that will claim to be able to cut at 63 micron, but the problem that we have relayed to us on a regular basis from our customers is that while this may happen sometimes, it is very difficult to find a system that will consistently deliver these results" explains Enda. "We can and do achieve these results with the EvoWash system - have a look at the testimonials section of our web site and you will see many comments from some of industries leading players on how we have solved precisely this problem."

In addition to the accurate cut points offered by the EvoWash system, Enda and Brian then list a whole host of further features of the EvoWash sand plant which they believe are responsible for the success of the plant in recent years. They go on to mention the dewatering capability, which produces material at approximately 12% moisture content, making it ready for market straight from the belts. The use of high performance components is also given as a major reason for success.

"We know that our customers are trying to ensure their plant is operational for as close to 100% of the time as possible" says Brian McCullough. "We aim to help them to achieve this through a focus on increasing wear resistance and minimising maintenance time."

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