From Muck to Gold, The Story of Super Sludge
Chemicals are commonly used to prevent the problem but at a cost. UK utility Thames Water, for example, estimates that it spends £130,000 to £200,000 per year on chemical dosing alone. A more recent development in wastewater management has been to extract phosphorus – the very problem potentially clogging up equipment – but as a solution, in the form of a fertiliser. Working with Canadian company Ostara, the London utility now extracts phosphorus in the form of 150 tonnes of crystalline, fertiliser pellets. This can be sold to farmers and used as a fertiliser on crops, lawns and gardens. Interestingly, by harvesting phosphorus as a fertiliser from sludge, it also reduces reliance upon nature’s own supplies.
Meanwhile major nutrient recovery company Ostara currently has seven facilities operating; six in North America and one in Europe (Thames Water in the UK), with another under construction in Amersfoot, the Netherlands. Several more are being planned, with China to be targeted in the future. “China is building its infrastructure up from the ground,” says Steve Wirtel, senior VP of technology for Ostara.
“For telephones, in many places instead of building landlines they’re going straight to cellular infrastructure. For wastewater, they’re building facilities that immediately manage nutrients. They do have nutrient problems in China. They are building their infrastructure with the biological phosphorus process in place and often with AD to recovery the energy from their plants. These are going to be readymade facilities.”
With water utilities morphing into clean tech energy companies with the potential to change the global fertiliser-food market, it seems sludge might well make dinner party conversation after all.