FULLSKALE- OCH SIMULERINGSSTUDIE AV BIOLOGISK FOSFORREDUKTION PA KÄPPALAVERKET / Biological Phosphorus Removal at Käppala Wastewater Treatment Plant – a Full-scale and Simulation Study
Käppala wastewater treatment plant on Lidingö was extended for nitrogen removal. Due to the new process configuration the plant could implement biological phosphorus removal (bio-P). To study the possiobilities to introduce bio-P removal at the plant, fullscale and simulation tests were conducted. Results from the fullscale tests did not give any good answers since metal salts added to the other trains affected the test train. Nevertheless, some bio-P removal was achieved- although with large influence from chemical precipitation. Simulations showed that bio-P removal capacity was poor due to large amount of secondary phosphorus release, i.e. phosphorus release not supporting bio-P removal. The reason for the large secondary phosphorus release was the large anoxic zone. The conclusion from this study was that the plant with its current process configuration and wastewater characteristics was not suitable for bio-P removal.