Water & Wastewater Treatment Magazine
Issue link: https://read.utilityweek.co.uk/i/374677
www.wwtonline.co.uk | WWT | SEPTEMBER 2014 | 19 The powder that comes out the other end of the process has no traces of sewage in it - it doesn't even smell Project focus: Bio-thermic digestion liquid waste facility. According to Edwards, the worst case scenario will see around 2 tonnes come out the other end, equating to an 80-86% reduction. However, because the residue is clean and dry, it no longer ends up in land• ll. This is helping RWR pick up new business because the water companies are keen on using waste contractors able to demonstrate 100% recycling capabilities. As for the future, RWR wants to in- vest in a bank of 8 or 10 BTDs, possibly even larger models than its existing machine. "Although having the BTD puts us ahead of our competitors for a while, we could get a lot more business from the sewage works if we had greater capacity," says Edwards. "We're taking around 40 tonnes a week from certain sewage works, but some want us to commit to 600 tonnes a week – we're not at that level yet." The potential for heavy investment exists thanks to the opportunity for rapid payback. According to Advetec, the operating cost of the BTD is around £1.20 per tonne. Compare this to current UK land• ll costs of £80-90 per tonne and the savings are plain to see. "With the typical con• guration required in the UK, independent data says that ROI is 1.9 years on average," says Shaw. "In fact, the shortest payback period we've seen is 11 months, albeit at an overseas installation. The technology is certainly attracting attention. According to Shaw, numerous water companies are currently demonstrating their desire to innovate by trialling the BTD, including Thames Water, Welsh Water, Wessex Water, Southern Water and United Utilities. For potential customers of this ilk, as well as reducing land• ll, processing waste on site has the potential to save a fortune in transportation costs. "We're already seeing signi• cant interest both here and abroad from water companies and municipal authorities where large volumes of organic waste are an issue," concludes Shaw. "Since the technology is completely scalable, banks of digesters can be linked to handle ever increasing volumes of waste, or each digester can be moved from site to site." Advetec's BTD is part of a complete system consisting of hoppers, shredders, augers, storage tanks and piping, designed and tailored to match speci• c customer requirements. For further reading go to wwtonline.co.uk – Innovations ● Unique here is Ad- vetec's understanding of aerobic bacteria, the bio-stimulant technol- ogy used to invigor- ate and accelerate the digestion process. The major diff erentiator with the BTD is the control and motivation of the bacteria within the unit and the replenishment of essential micronutrients that ensure they remain healthy. ● The use of thermo- philic bacteria allows the BTD to run at tempera- tures in excess of 180°C, far above other in-vessel solutions. This not only speeds up the process, but makes it possible to digest already part- treated material from AD plants, for example. RWR is currently taking about 40 tonnes from sewage works each week, but there is huge demand and some works have asked for a commitment of up to 600 tonnes per week