Sammanfattning

Drinking water treatment plants (DWTPs) designed to remove natural organic matter (NOM) are challenged as concentrations of NOM in raw waters are increasing. Here, we assess seasonal differences in NOM quality and quantity, from raw waters to the distribution network, at three large DWTPs in Oslo, Stockholm and Helsinki. Samples, collected during stable stratification in both winter and summer and during the autumnal turnover, were analysed for NOM concentrations and composition. The NOM was characterized by common routine parameters, size and content (TFF, LC-OCD, fluorescence) and biodegradability. The NOM concentration decreased to 2.5 mg/L (55%), 4.0 mg/L (48%) and 5.7 mg/L (76%) at the respective DWTPs in Oslo, Stockholm and Helsinki. The NOM in raw waters were predominantly in the largest size fraction (> 50 kDa), in particular from Oslo. High MW fractions > 50 kDa and humics remained the largest fractions with minimum 30% and maximum 80% of the total NOM. The BDOC in treated water < 0.3 mg/L and the conditions in the distribution network imply low probability for bacteria regrowth.The multi-step treatment consisting of coagulation/flocculation, sedimentation, rapid sand filtration, ozonation and biological activated carbon filtration (BAC) was most effective in removing NOM. Coagulation/flocculation followed by sedimentation and sand filtration were critical, especially for the removal of biopolymers and humics, and somewhat for building blocks. The sand filtration provided up to 25% additional removal of biopolymers and below 7% removal of other fractions. The ozonation and BAC was more effective and removed 11% of biopolymers, and about 35% of building blocks and LMW neutrals.

Nyckelord

NOM fractions; DOM removal; Full-scale drinking water treatment; Membrane size fractionation; Liquid chromatography - organic carbon detection (LC-OCD); Biodegradable dissolved organic carbon (BDOC)

Publicerad i

Journal of Environmental Management
2019, Volym: 241, sidor: 427-438
Utgivare: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD

SLU författare

• Köhler, Stephan

  • Institutionen för vatten och miljö, Sveriges lantbruksuniversitet
    

Globala målen

SDG6 Säkerställa tillgången till och en hållbar förvaltning av vatten och sanitet för alla


UKÄ forskningsämne

Vattenbehandling


Publikationens identifierare

DOI: https://doi.org/10.1016/j.jenvman.2019.02.024

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/100642