Viridor GRREC Polmadie ECS visit Monday 29th June 2016
A group of 11 people met at the Visitor centre for a presentation by the Community Benefits Officer for Viridor Polmadie. I had previously visited the old Polmadie recycling depot (Materials Recovery Facility), run by Glasgow City Council (GCC) in 2012 to see for myself how the blue bin contents were dealt with – it was noisy and smelly and we came away with huge respect for the people working there! Many of us attending had watched with interest, as the old buildings came down and the new facility took shape; we all wondered what benefits it would bring to the city………..
I should point out that there is a great deal of information and videos, including a time lapse video, from start to the present day, on the GRREC web site https://www.viridor.co.uk/our-developments/glasgow-rrec/ so do take a look.
The Glasgow Recycling and Renewable Energy Centre (GRREC) is a joint partnership development between Glasgow City Council and Viridor and due to open for business at the end of 2016.
According to Viridor, the facility is set to revolutionise the way Glasgow handles its 200,000 tonnes of annual residual/ green bin waste over a period of 25 years and once operational GRREC will be one of Europe’s most advanced recycling and energy recovery facilities; uniquely different to any current site.
We will continue to use our blue, purple and brown bins as usual, but what happens to the contents of the green bin will be very different.
Having been collected in the usual way by council bin-wagons, the green bin waste will be diverted from landfill and will arrive at the plant’s reception hall from where it passes through 3 stages.
Stage 1
The first stage is Smart Materials Recycling Facility (Smart MRF) where materials will be sorted through various sorting technology including two massive, slightly angled drums (Trommels) which rotate, sorting materials according to shape, weight and size onto a series of conveyor belts. If you don’t know much about how a Materials Recovery Facility works then here’s a You-tube clip; https://www.youtube.com/watch?v=7CFE5tD1CCI
Smart MRF does it even better and although some pickers are employed on conveyor lines, this is greatly reduced. At the end of the Smart MRF process all the plastics, metal & paper items which can be recycled have been removed, sorted and baled, ready to be sold on. Because of the wide ranging nature of the green bin waste, the sorting is not as ‘clean’ as that achieved by the sorting of blue bin contents by GCC, but it is one of the main ways Glasgow can push up the recycling figure from the current 30% towards the target of 70% by 2025. Until now this has proved an impossible task despite the huge improvements in Glasgow’s recycling rates in recent years. This has often been hindered by the large numbers of flats and tenements where it can be difficult for households to separate recyclables.
(By the way try to remember to wash out your bottles and cans, take the tops off plastic bottles & glass bottles and don’t bother trying to crush your cans!)
Stage 2
The next stage is Anaerobic Digestion (AD). The organic (includes food) waste extracted by the Smart MRF is prepared for use in AD by shredding it and mixing it with water to form a sludge. The sludge is put through a centrifuge to ensure non organic items are removed, and then transferred to an AD tank where bacteria break it down over a period of about 14 – 18 days, producing Bio-gas (methane). The Bio-gas is captured and stored for use in a Combined Heat & Power (CHP) plant to produce heat & electricity. Some of this heat is used around the plant and to dry the final sludge residue (Refuse Derived Fuel – RDF) which is then transferred to stage 3. Electricity produced is used on site and will be exported to the National Grid.
Stage 3
The Advanced Conversion Facility (ACF) is the final stage, securing the target of 95% diversion rate from landfill by 2025. The RDF produced at the end of stage 2 is transferred to a series of thermal conversion units which heat (not burn) the material to a very high temperature in low oxygen conditions to produce a synthetic gas (gasification). The gas is captured and fully combusted in a separate chamber to produce super heated steam which in turn creates electricity via a turbine, fed into the National Grid, although in time this might be a local network.
Alternatively the steam may be diverted in the future to support a district heat network (a potential 8000 homes).
The final residue from the gasification process can be used as aggregate in construction.
The whole project, already attracting international interest, is sustainable by design. For example, over 11,000 cubic metres of rubble from the former building and chimneys, have been recycled on site to form mat foundations during construction of the GRREC. Strict noise, odour and dust controls operate throughout. Rain water is harvested from the roof for use around the plant.
When the new visitor centre is open, you’ll be able to see some of the workings from the viewing gallery.
Viridor has and continues to provide a range of community benefits such as recruitment and training- over 250 new jobs, including 25 apprentices, work placements, university graduate programmes – Small & Medium Enterprise as well as Social Enterprise support and training and educational awareness for educational establishments in Glasgow. Local business have been encouraged to be apart of the supply chain. More information can be found on the web site.
I and all those who attended are very grateful to Karen for putting together a very interesting and informative presentation, answering a wide range of questions, encouraging us to enthuse others and making us most welcome at the Centre. Thanks Karen, we look forward to a return visit once the plant is in full swing!
