On the 4rd of December the WOW! project team gathered in Germany Lünen at the Remondis office. Part of the program was a visit to one of Remondis’ pilot plants, the TetraPhos. This process recovers valuable phosphorus from sewage sludge ash in form of phosphoric acid, which is mandatory for big sewage treatment plants in Germany from 2029 on. A good example for recovering valuable products from “waste water” which was an inspiring visit for the team!
More information about the REMONDIS Tetraphos®:
The REMONDIS TetraPhos® process taking mono-incineration ash from fluidized bed combustion of municipal sewage sludge. The TetraPhos® process treats the ash with phosphoric acid, then, after separation of acid insoluble residue , purifies the resulting leachate with sulphuric acid, ion-exchange and selective nano-filtration to generate an industrial quality phosphoric acid (brandname RePacid®). The process also enables recovery of iron and aluminium salts as coagulants, for recycling in sewage works phosphorus removal, gypsum intended for production of building material and a residual ash waste that either is used in the cement industry or if the latter is not possible is landfilled. Around 80% of the ash phosphorus is recovered in the phosphoric acid. The process is economical under consideration of all cost (including investments). TetraPhos® is designed as part of an integrated plant consisting of incineration facility and P-Recycling installation thereby allowing for efficient use of waste heat for concentration of RePacid®. The rollout of the technology will be implemented as public-private partnership between municipal partners and REMONDIS. First implementation of this model will be a cooperation with HAMBURG WASSER. From 2019 on a large scale TetraPhos® plant at the WWTP in Hamburg will treat 20.000 tons of ash annually, thereby recycling 1600 tons of P.