Validation of the Ivar Thermal Drying Plant in Stavanger, Norway
Tornes, O.1, Johnsen, G.1, Paulsrud, B.2, 1IVAR IKS, Norway, 2Aquateam AS, Norway
(free)
Norway is among the leading countries in the world with regard to land application of biosolids with
about 90 % recycling. In order to achieve the high percentage of biosolids recycling, stringent
standards have been set for the content of heavy metals, odour control and pathogens. Therefore,
stabilisation and disinfection (hygienisation) of all biosolids are required prior to land application. The
treated sludge shall not contain Salmonella sp., infective helminth eggs, and less than 2500 grams of
faecal coliforms per gram dry solids.
In order to comply with the requirement for inactivation of viable helminth eggs , recommended sludge
treatment processes are validated against their ability to inactivate these eggs, since this is the crucial
criteria for pathogen control in the Norwegian biosolids regulation. In all process validation tests viable
eggs of Ascaris suum have been used. The first validation of a thermal drying process in Norway was
recently performed at IVAR’s Regional Wastewater Treatment Plant in Stavanger.
The paper gives a short summary of the Norwegian biosolids regulation, overview of recommended
operating data (critical control points and critical limits) for validated sludge treatment processes,
description of the validation method applied for the IVAR thermal drying plant and results achieved.
KEYWORDS
Biosolids, HACCP, pathogen control QA system, sludge treatment processes, thermal drying,
validation.
