place Case Studies

Altenrhein, Switzerland

The WWTP of Altenrhein operates residential drainage-, wastewater- and sludge treatment of 17 municipalities in two federal states (St. Gallen and Appenzell-Ausserrhoden).
The treated water reaches Lake of Constance via the mouth of the Old Rhine. Both Lake of Constance and the Old Rhine are considered priority water bodies for protection. Lake of Constance also serves as a drinking water reservoir. The topographical conditions around these 17 municipalities vary greatly which makes the water transportation more challenging. For this reason, special structures are required. Sludge that is being treated in Altenrhein originates from their own water treatment and is also being transported to the site by other WWTP of Eastern Switzerland. The WWTP of Altenrhein (AVA) has advanced energy-efficient sludge management technologies for 300.000 pe of sludge: sludge is dried on site and is co-incinerated in cement works. The heat for sludge drying is generated by burning of sewage gas and by heat recovery from wastewater using heat pumps.  AVA took a full-scale removal of micropollutants by ozonation and active carbon adsporption into operation in 2019 and a ammonia membrane stripping unit from sludge dewatering emplying an innovative membrane contactor with a novel low fouling membrane module in 2021 a total investment of EUR 20 Mio in innovative technologies. After the project  AVA will have a clear idea of the technical and financial feasibility of on-site activated carbon regeneration and production of fresh activated carbon using locally available sludge and biomass. Long-term experience with full-scale installations for micropollutant removal and N recovery gained with the installations at Altenrhein will reduce investment risks, enhance chances of replicability. AVA also gathers the all necessary information to take an investment decision regarding the construction of a P-K fertilizer production unit. This novel thermochemical process transforms sewage sludge into a market grade P-K-fertilizer. Thereby heavy metals are partly removed and the fully plant available mineral phase CaKPO4 is produced. The process has been piloted in a large-scale pilot to gain further operational experience.

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Last update on 2022-03-14 16:58 UTC