Wild microorganism and plankton decay in ballast water treatments by solar disinfection (SODIS) and advanced oxidation processes

Ballast water (BW) is a dead weight used by ships to provide stability in their journeys. It poses health, economic and ecological problems. Since 2017, the International Maritime Organization-IMO mandated management of BW. This research compares plankton mortality and microorganism inactivation in different BW treatments to identify possible decay models. Treatments include solar radiation (Srad), UV, H2O2 and advanced oxidation processes (AOPs). In the wild populations, the disinfection capacity was measured in natural seawater pumped from the Santa Marta port zone in Colombia. AOPs showed different models and effectiveness according to the treatment and microorganism. Plankton larger than 50 μm was the most resistant; therefore, it must be removed first by a previous filter. Wild microorganisms showed log-linear and log-linear tail decay models for most AOPs in E. coli. For Vibrio, the models were log-lineal tail and biphasic models. [Display omitted] Zooplankton larger than 50 μm can be affected by natural solar radiation.Treatments by natural solar radiation can negatively affect Vibrio and Enterococcus inactivation.Wild E. coli did not show initial resistance in contrast to lab strains.Phytoplankton exposed only to direct solar radiation can affect the treatment effectiveness.