Water Treatment Plant Installed at PMG Depot Boosts Recycling Capacity by 25%

Gritbuster (UK) has installed a new water treatment plant at PMG Services’ depot in Bristol, boosting the waste recycling capacity at the site by 25%, improving its environmental performance and delivering considerable additional savings and revenue each year.

The depot which was opened in 2012 is the first facility in the South West of England licensed to receive, treat and recycle road sweepings and gully waste and the only one its kind to have its quality protocol approved by The Environment Agency. It handles waste brought to the depot by PMG’s own fleet of 35 vehicles plus from three local councils. Cleaning and separating the waste to the highest possible quality is critical to the plant’s performance but this involves using a lot of water.

When the site first opened, the waste water resulting from the recycling process was put in two underground holding tanks. However PMG Services found that the holding tanks quickly filled up with silt.

Stuart Knight, operations Manager at PMG Services (Bristol) Ltd explains: “Every three weeks the waste recycling plant at our site had to stop while we cleaned out the sludge from the storage tanks. This took a week to complete so we were routinely losing 25% of our processing time, and the situation was even worse in the winter due to the wet weather.”

With winter approaching in November 2014 Stuart Knight approached Gritbuster, part of the Siltbuster Group, the washing and waste water treatment specialists, for a solution. The company suggested PMG trial a package of two Siltbuster HB40R clarifiers, dosed with flocculant which could handle a flow of 70m3/hr of wash water from the existing plant. Twin sludge pumps were supplied to pump the settled sludge to a containerised holding tank, complete with agitation mixers. The sludge tank, equipped with a tanked hook-up, enabled PMG’s own tankers to periodically remove the sludge and take this to a local facility for dewatering.

Stuart Knight comments: “The hired system was quickly installed and immediately improved our recycling no end. It meant we could move to a continuous process. It eliminated all of our down time as we no longer had holding tanks to clean out. This is a crucial benefit as downtime means money lost and recycling opportunities missed!  Importantly my team also found the equipment easy to use and it involved minimal maintenance.”

The pilot was so successful that PMG asked Gritbuster to supply a permanent water treatment plant for the site. This is broadly the same as the solution trialled but involves a very space efficient single, larger Siltbuster HB100R lamella clarifier.  Siltbuster has also supplied a perimeter access walkway to make maintenance even easier.

The new water treatment plant has transformed the performance of the site which processes 20,000 tonnes of road sweepings and gully waste each year.  It can now process 5,000 tonnes more annually, with zero waste going to landfill.  The 200 tonnes of This is combination of benefits is generating considerable cost savings, and increase to revenue from increased waste processing, for PMG each year.

Stuart Knight concludes: “We are typically processing an extra 300 – 400 tonnes per month due to the installation which is a great gain in efficiency. Preserving the environment is central to our business so to have a solution which not only enables us to process more waste and reuse massively more aggregate but also makes our process even more sustainable is an absolute win win for us, our customers and the environment.”