TY - JOUR
T1 - Ballast water treatment and bacteria
T2 - Analysis of bacterial activity and diversity after treatment of simulated ballast water by electrochlorination and UV exposure
AU - Petersen, Nanna B.
AU - Madsen, Torben
AU - Glaring, Mikkel A.
AU - Dobbs, Fred C.
AU - Jørgensen, Niels O.G.
PY - 2019/1/15
Y1 - 2019/1/15
N2 - Effects of ballast water (BW) treatment by ultra-violet (UV) light and electrochlorination (EC) on survival, activity and diversity of marine bacterioplankton and release of organic matter from cell damage were examined at discharge in a large-scale BW test facility (250 m3 tanks) at Hundested harbour, Denmark. The tests were performed in accordance with the requirements for type approval testing by International Maritime Organization (IMO) and US Coast Guard. After treatment, the water was held in the tanks for one day (EC) before discharge, or 6 days (UV, including also a final UV re-treatment) before discharge. In the discharged and treated water, numbers of viable bacteria and bacterial growth rate had decreased significantly relative to the untreated water, but the total number of bacteria only was reduced in the EC-treated water. After additional storage for up to 10 days in small-scale laboratory incubations, significant regrowth of bacteria was observed after either treatment. Sequencing of 16S rRNA gene amplicons demonstrated that α-Proteobacteria initially were dominant, but γ-Proteobacteria dominated after regrowth. Bacteria used to document BW treatment efficiency (E. coli, Vibrio spp., enterococci) survived both treatments; neither treatment reduced the risk of pathogen dispersal. Concentrations of amino acids in the water were used as indicators of treatment-induced cell damage and demonstrated higher concentrations at discharge, but only after the EC treatments. Our results indicate that activity of bacteria, rather than their abundances, should be used when examining effects by ballast water treatment on microorganisms and that none of the examined treatment technologies could eliminate pathogenic bacteria.
AB - Effects of ballast water (BW) treatment by ultra-violet (UV) light and electrochlorination (EC) on survival, activity and diversity of marine bacterioplankton and release of organic matter from cell damage were examined at discharge in a large-scale BW test facility (250 m3 tanks) at Hundested harbour, Denmark. The tests were performed in accordance with the requirements for type approval testing by International Maritime Organization (IMO) and US Coast Guard. After treatment, the water was held in the tanks for one day (EC) before discharge, or 6 days (UV, including also a final UV re-treatment) before discharge. In the discharged and treated water, numbers of viable bacteria and bacterial growth rate had decreased significantly relative to the untreated water, but the total number of bacteria only was reduced in the EC-treated water. After additional storage for up to 10 days in small-scale laboratory incubations, significant regrowth of bacteria was observed after either treatment. Sequencing of 16S rRNA gene amplicons demonstrated that α-Proteobacteria initially were dominant, but γ-Proteobacteria dominated after regrowth. Bacteria used to document BW treatment efficiency (E. coli, Vibrio spp., enterococci) survived both treatments; neither treatment reduced the risk of pathogen dispersal. Concentrations of amino acids in the water were used as indicators of treatment-induced cell damage and demonstrated higher concentrations at discharge, but only after the EC treatments. Our results indicate that activity of bacteria, rather than their abundances, should be used when examining effects by ballast water treatment on microorganisms and that none of the examined treatment technologies could eliminate pathogenic bacteria.
KW - Bacterial diversity changes
KW - Bacterial pathogens
KW - Bacterial regrowth
KW - Ballast water treatment
KW - Cell destruction
UR - http://www.scopus.com/inward/record.url?scp=85051483811&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2018.08.080
DO - 10.1016/j.scitotenv.2018.08.080
M3 - Journal article
C2 - 30121040
AN - SCOPUS:85051483811
SN - 0048-9697
VL - 648
SP - 408
EP - 421
JO - Science of the Total Environment
JF - Science of the Total Environment
ER -
