Drinking water quality and formation of biofilms in an office building during its first year of operation, a full scale study Jenni Inkinen a, *, Tuija Kaunisto b,1 , Anna Pursiainen c , Ilkka T. Miettinen c , Jaana Kusnetsov c , Kalle Riihinen d,2 , Minna M. Keina ¨ nen-Toivola a,b,1 a Satakunta University of Applied Sciences, Energy and Construction, WANDER Nordic Water and Materials Institute, Sinkokatu 11, FI-26100 Rauma, Finland b Prizztech Ltd. /WANDER Nordic Water and Materials Institute, Sinkokatu 11, FI-26100 Rauma, Finland c National Institute for Health and Welfare (THL), Water and Health Unit, P.O. Box 95, FI-70701 Kuopio, Finland d Quantifire Ltd., Innopoli 2, Tekniikantie 14, FI-02150 Espoo, Finland article info Article history: Received 19 March 2013 Received in revised form 6 November 2013 Accepted 9 November 2013 Available online 21 November 2013 Keywords: Biofilms Pipeline network Copper pipe Drinking water PEX pipe abstract Complex interactions existing between water distribution systems’ materials and water can cause a reduction in water quality and unwanted changes in materials, aging or corrosion of materials and formation of biofilms on surfaces. Substances leaching from pipe materials and water fittings, as well as the microbiological quality of water and formation of biofilms were evaluated by applying a Living Lab theme i.e. a research in a real life setting using a full scale system during its first year of operation. The study site was a real office building with one part of the building lined with copper pipes, the other with cross-linked polyethylene (PEX) pipes thus enabling material comparison; also differences within the cold and hot water systems were analysed. It was found that operational conditions, such as flow conditions and temperature affected the amounts of metals leaching from the pipe network. In particular, brass components were considered to be a source of leaching; e. g. the lead concentration was highest during the first few weeks after the commissioning of the pipe network when the water was allowed to stagnate. Assimilable organic carbon (AOC) and microbially available phosphorus (MAP) were found to leach from PEX pipelines with minor effects on biomass of the biofilm. Cultivable and viable biomass (heterotrophic plate count (HPC), and adenosine triphosphate (ATP)) levels in biofilms were higher in the cold than in the hot water system whereas total microbial biomass (total cell count (DAPI)) was similar with both systems. The type of pipeline material was not found to greatly affect the microbial biomass or Alpha-, Beta- and Gammaproteobacteria profiles (16s rRNA gene copies) after the first one year of operation. Also microbiological quality of water was found to deteriorate due to stagnation. ª 2013 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: þ358 44 710 3173. E-mail addresses: jenni.inkinen@vesi-instituutti.fi, jenni.inkinen@samk.fi (J. Inkinen), tuija.kaunisto@wander.fi (T. Kaunisto), anna. pursiainen@thl.fi (A. Pursiainen), ilkka.miettinen@thl.fi (I.T. Miettinen), jaana.kusnetsov@thl.fi (J. Kusnetsov), kalle.riihinen@teollisuu- denvesi.fi (K. Riihinen), minna.keinanen-toivola@wander.fi (M.M. Keina ¨ nen-Toivola). 1 Present address: Satakunta University of Applied Sciences, Energy and Construction, WANDER Nordic Water and Materials Institute, Sinkokatu 11, FI-26100 Rauma, Finland. 2 Present address: Teollisuuden Vesi Oy, Tekniikantie 2, FI-02150 Espoo, Finland. Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/watres water research 49 (2014) 83 e91 0043-1354/$ e see front matter ª 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.watres.2013.11.013