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We develop an abstract theory of flows of geometric 퐻-structures, i.e., flows of tensor fields defining 퐻-reductions of the frame bundle, for a closed and connected subgroup H ⊂ SO ⁢ (n) , on any connected and oriented 푛-manifold with sufficient topology to admit such structures. The first part of the article sets up a unifying theoretical framework for deformations of 퐻-structures, by way of the natural infinitesimal action of GL ⁢ (n , R) on tensors combined with various bundle decompositions induced by 퐻-structures. We compute evolution equations for the intrinsic torsion under general flows of 퐻-structures and, as applications, we obtain general Bianchi-type identities for 퐻-structures, and, for closed manifolds, a general first variation formula for the L 2 -Dirichlet energy functional ℰ on the space of 퐻-structures. We then specialise the theory to the negative gradient flow of ℰ over isometric 퐻-structures, i.e., their harmonic flow. The core result is an almost-monotonocity formula along the flow for a scale-invariant localised energy, similar to the classical formulas by Chen–Struwe [M. Struwe, On the evolution of harmonic maps in higher dimensions, J. Differential Geom.28 (1988), 3, 485–502; Y. M. Chen and M. Struwe, Existence and partial regularity results for the heat flow for harmonic maps, Math. Z.201 (1989), 1, 83–103] for the harmonic map heat flow. This yields an 휀-regularity theorem and an energy gap result for harmonic structures, as well as long-time existence for the flow under small initial energy, relative to the L ∞ -norm of initial torsion, in the spirit of Chen–Ding [Y. M. Chen and W. Y. Ding, Blow-up and global existence for heat flows of harmonic maps, Invent. Math.99 (1990), 3, 567–578]. Moreover, below a certain energy level, the absence of a torsion-free isometric 퐻-structure in the initial homotopy class imposes the formation of finite-time singularities. These seemingly contrasting statements are illustrated by examples on flat 푛-tori, so long as the set [ S n , SO ⁢ (n) / H ] of homotopy classes of maps S n → SO ⁢ (n) / H contains more than one element and the universal cover of SO ⁢ (n) / H is a sphere, e.g. when n = 7 and H = G 2 , or n = 8 and H = Spin ⁢ (7) . [ABSTRACT FROM AUTHOR]

We describe the 10-dimensional space of Sp (2) -invariant G 2 -structures on the homogeneous 7-sphere S 7 = Sp (2) / Sp (1) as Ω + 3 (S 7) Sp (2) ≃ R + × Gl + (3 , R) . In those terms, we formulate a general Ansatz for G 2 -structures, which realises representatives in each of the 7 possible isometric classes of homogeneous G 2 -structures. Moreover, the well-known nearly parallel round and squashed metrics occur naturally as opposite poles in an S 3 -family, the equator of which is a new S 2 -family of coclosed G 2 -structures satisfying the harmonicity condition div T = 0 . We show general existence of harmonic representatives of G 2 -structures in each isometric class through explicit solutions of the associated flow and describe the qualitative behaviour of the flow. We study the stability of the Dirichlet gradient flow near these critical points, showing explicit examples of degenerate and nondegenerate local maxima and minima, at various regimes of the general Ansatz. Finally, for metrics outside of the Ansatz, we identify families of harmonic G 2 -structures, prove long-time existence of the flow and study the stability properties of some well-chosen examples. [ABSTRACT FROM AUTHOR]

Background: Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a promising technique for palliative treatment of bone pain. In this study, the effects of MR-HIFU ablation on bone mechanics and modeling were investigated. Methods: A total of 12 healthy rat femurs were ablated using 10 W for 46 ± 4 s per sonication with 4 sonications for each femur. At 7 days after treatments, all animals underwent MR and single photon emission computed tomography/computed tomography (SPECT/CT) imaging. Then, six animals were euthanized. At 1 month following ablations, the remaining six animals were scanned again with MR and SPECT/CT prior to euthanization. Thereafter, both the HIFU-treated and contralateral control bones of three animals from each time interval were processed for histology, whereas the remaining bones were subjected to micro-CT (μCT), three-point bending tests, and micro-finite element (micro-FE) analyses. Results: At 7 days after HIFU ablations, edema formation around the treated bones coupled with bone marrow and cortical bone necrosis was observed on MRI and histological images. SPECT/CT and μCT images revealed presence of bone modeling through an increased uptake of 99mTc-MDP and formation of woven bone, respectively. At 31 days after ablations, as illustrated by imaging and histology, healing of the treated bone and the surrounding soft tissue was noted, marked by decreased in amount of tissue damage, formation of scar tissue, and sub-periosteal reaction. The results of three-point bending tests showed no significant differences in elastic stiffness, ultimate load, and yield load between the HIFU-treated and contralateral control bones at 7 days and 1 month after treatments. Similarly, the elastic stiffness and Young's moduli determined by micro-FE analyses at both time intervals were not statistically different. Conclusions: Multimodality imaging and histological data illustrated the presence of HIFU-induced bone damage at the cellular level, which activated the bone repair mechanisms. Despite that, these changes did not have a mechanical impact on the bone. [ABSTRACT FROM AUTHOR]

A methodology is established in this research which permits to describe the movement of a lower limb using closed kinematic chains. This analysis is developed with the aim to determine the location of the center of rotation (CR) of the knee joint in the sagittal plane. Flexion-extension tests were carried out on one of the lower limbs of a healthy patient without pathological antecedents. When the patient does articular movement (flexion-extension), a video equipment and a software determine the position of four passive markers installed on the lower limb. The information obtained from the markers is applied to the proposed model which allows to locate the center of rotation of the knee joint. Hence it was concluded that the CR of the knee joint undergoes a relative movement with respect to the fixed point marked on the lower limb. The results prove that the knee joint established in the sagittal plane does not show the behavior of a complete joint (a joint with one degree of freedom) as it has been described in other studies. [ABSTRACT FROM AUTHOR]

Harmful algal blooms (HABs) in coastal areas similarly impact both ecosystems and human health. The translocation of phytoplankton species via maritime transport can potentially promote the growth of HABs in coastal systems. Accordingly, ballast water must be disinfected. The main goal of this study is to assess the effectiveness of different emerging biocides, including H 2 O 2 , peracetic acid (PAA), peroxymonosulfate (PMS), and peroxydisulfate (PDS). The effectiveness of these biocides is compared with that of conventional chlorination methods. Their effects on two ichthyotoxic microalgae with worldwide distribution, i.e., Prymnesium parvum and Heterosigma akashiwo, are examined. To ensure the prolonged effectiveness of the different reagents, their concentration-response curves for 14 days are constructed and examined. The results suggest a strong but shorter effect by PMS (EC50 = 0.40-1.99 mg·L -1 ) and PAA (EC50 = 0.32-2.70 mg·L -1 ), a maintained effect by H 2 O 2 (EC50 = 6.67-7.08 mg·L -1 ), and a negligible effect by PDS. H. akashiwo indicates higher resistance than P. parvum, except when H 2 O 2 is used. Based on the growth inhibition performance and consumption of the reagents as well as a review of important aspects regarding their application, using H 2 O 2 , PAA, or PMS can be a feasible alternative to chlorine-based reagents for inhibiting the growth of harmful phytoplankton., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Ultraviolet (UV) radiation is a well-implemented process for water disinfection. The development of emergent UV sources, such as light-emitting diodes (LEDs), has afforded new possibilities for advanced oxidation processes. The emission wavelength is considered to be an important factor for photo-chemical processes in terms of both biological damage and energetic efficiency, as the inactivation mechanisms and mode-of-action may differ according to the wavelength that is applied. In addition, these processes merit exploration for inactivating emerging pathogens, such as marine vibrios, that are important bacteria to control in maritime activities. The main goal of this study was to compare the disinfection efficacy of several UV-LED driven processes with different modes of action. First, the effect of UV-LEDs was assessed at different UV ranges (UV-A, UV-B, or UV-C). Second, the possible enhancement of a combination with hydrogen peroxide (H 2 O 2 ) or peroxymonosulfate salt (HSO 5 - ) was investigated under two different application strategies, i.e. simultaneous or sequential. The results obtained indicate a high sensitivity of Vibrio alginolyticus to UV radiation, especially under UV-B (k obs  = 0.24 cm 2 /mJ) and UV-C (k obs  = 1.47 cm 2 /mJ) irradiation. The highest inactivation rate constants were obtained for UV/HSO 5 - (k obs (cm 2 /mJ)=0.0007 (UV-A); 0.39 (UV-B); 1.79 (UV-C)) with respect to UV/H 2 O 2 (k obs (cm 2 /mJ)=0.0006 (UV-A); 0.26 (UV-B); and 1.54 (UV-C)) processes, however, regrowth was avoided only with UV/H 2 O 2 . Additionally, the disinfection enhancement caused by a chemical addition was more evident in the order UV-A > UV-B > UV-C. By applying H 2 O 2 (10 mg/L) or HSO 5 - (2.5 mg/L) in a sequential mode before the UV, negligible effects were obtained in comparison with the simultaneous application. Finally, promising electrical energy per order (EE O ) values were obtained as follows: UV/HSO 5 - (EE O (kWh/m 3 )=1.68 (UV-A); 0.20 (UV-B); 0.04 (UV-C)) and UV/H 2 O 2 (EE O (kWh/m 3 )=2.15 (UV-A); 0.32 (UV-B); 0.04 (UV-C)), demonstrating the potential of UV-LEDs for disinfection in particular activities such as the aquaculture industry or maritime transport., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Harmful algal blooms in coastal areas can significantly impact a water source. Microorganisms such as cyanobacteria and associated pathogenic bacteria may endanger an ecosystem and human health by causing significant eco-hazards. This study assesses the efficacy of two different reagents, H2O2 and S2O82−, as (pre-)treatment options for algae-laden waters. Anabaena sp. and Vibrio alginolyticus have been selected as target microorganisms. With the objective of activating H2O2 or S2O82−, additional experiments have been performed with the presence of small amounts of iron (18 µmol/L). For the cyanobacterial case, H2O2-based processes demonstrate greater efficiency over that of S2O82−, as Anabaena sp. is particularly affected by H2O2, for which >90% of growth inhibition has been achieved with 0.088 mmol/L of H2O2 (at 72 h of exposure). The response of Anabaena sp. as a co-culture with V. alginolyticus implies the use of major H2O2 amounts for its inactivation (0.29 mmol/L of H2O2), while the effects of H2O2/Fe(II) suggests an improvement of ~60% compared to single H2O2. These H2O2 doses are not sufficient for preventing the regrowth of V. alginolyticus after 24 h. The effects of S2O82− (+ Fe(II)) are moderate, reaching maximum inhibition growth of ~50% for Anabaena sp. at seven days of exposure. Nevertheless, doses of 3 mmol/L of S2O82− can prevent the regrowth of V. alginolyticus. These findings have implications for the mitigation of HABs but also for the associated bacteria that threaten many coastal ecosystems.

Pharmaceutically active compounds (PhACs) widely present in urban wastewater effluents pose a threat to ecosystems in the receiving aquatic environment. In this work, efficiency of granular activated carbon (GAC) - based catalytic processes, namely catalytic wet peroxide oxidation (CWPO), peroxymonosulfate oxidation (PMS/GAC) and peroxydisulfate oxidation (PDS/GAC) at ambient temperature and pressure were studied for removal of 22 PhACs (ng L -1 level) that were present in secondary effluents of real urban wastewater. Concentrations of PhACs were measured using Ultra Performance Liquid Chromatography - Triple Quadrupole Mass Spectrometry (UPLC-QqQ-MS/MS). Catalytic experiments were conducted in discontinuous mode using up-flow fixed bed reactors with granular activated carbon (GAC) as a catalyst. The catalyst was characterized by means of N 2 adsorption-desorption isotherm, mercury intrusion porosimetry (MIP), elemental analysis, X-ray fluorescence spectroscopy (WDXRF), X-ray diffraction (XRD), thermal gravimetry and differential temperature analyses coupled mass spectrometry (TGA-DTA-MS). Results indicate that the highest efficiency in terms of TOC removal was achieved during CWPO performed at optimal operational conditions (stoichiometric dose of H 2 O 2 ; TOC removal ~ 82%) followed by PMS/GAC (initial PMS concentration 100 mg L -1 ; TOC removal ~73.7%) and PDS/GAC (initial PDS concentration 100 mg L -1 ; TOC removal ~ 67.9%) after 5 min of contact time. Full consumption of oxidants was observed in all cases for CWPO and PDS/GAC at contact times of 2.5 min, while for PMS/GAC it was 1.5 min. In general, for 18 out of 22 target PhACs, very high removal efficiencies (> 92%) were achieved in all tested processes (including adsorption) performed at optimal operational conditions during 5 min of contact time. However, moderate (40 - 70%) and poor (< 40%) removal efficiencies were achieved for salicylic acid, ofloxacin, norfloxacin and ciprofloxacin, which can be possibly attributed to insufficient contact time. Despite high efficiency of all studied processes for PhACs elimination from urban wastewater effluent, CWPO seems to be more promising for continuous operation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021. Published by Elsevier Ltd.)

Due to the increasing number of ecosystem invasions with the introduction of exogenous species via ballast water, the International Maritime Organization adopted the Ballast Water Convention (BWMC). The BWMC establishes standards for the concentration of viable organisms in a ballast water discharge. Ultraviolet (UV) irradiation is commonly used for treating ballast water; however, regrowth after UV irradiation and other drawbacks have been reported. In this study, improvement in UV treatment with the addition of hydrogen peroxide or peroxymonosulfate salt was investigated using the microalgae Tetraselmis suecica as the target organism. Results reported that each of these reagents added in a concentration of 10 ppm reduced the concentration of initial cells by more than 96%, increased the UV inactivation rate, and enabled reaching greater level of inactivation with the treatment. These improvements imply a reduction of the UV doses required for a consistent compliance with the BWMC standards., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The development of technologically advanced recirculation aquaculture systems (RAS) implies the reuse of water in a high recirculation rate (>90%). One of the most important phases for water management in RAS involves water disinfection in order to avoid proliferation of potential pathogens and related fish diseases. Accordingly, different approaches have been assessed in this study by performing a comparison of photolytic (UV-LEDs) at different wavelengths (λ = 262, 268 and 262 + 268 nm), photochemical (UV-LEDs/H 2 O 2 , UV-LEDs/HSO 5 - and UV-LEDs/S 2 O 8 2- ) and photocatalytic (TiO 2 /SiO 2 /UV-LEDs and ZnO/SiO 2 /UV-LEDs) processes for the disinfection of water in RAS streams. Different laboratory tests were performed in batch scale with real RAS stream water and naturally occurring bacteria (Aeromonas hydrophyla and Citrobacter gillenii) as target microorganisms. Regarding photolytic processes, higher inactivation rates were obtained by combining λ 262+268 in front of single wavelengths. Photochemical processes showed higher efficiencies by comparison with a single UV-C process, especially at 10 mg L -1 of initial oxidant dose. The inactivation kinetic rate constant was improved in the range of 15-38%, with major efficiency for UV/H 2 O 2  ∼ UV/HSO 5 -  > UV/S 2 O 8 2- . According to photocatalytic tests, higher efficiencies were obtained by improving the inactivation kinetic rate constant up to 55% in comparison with a single UV-C process. Preliminary cost estimation was conducted for all tested disinfection methods. Those results suggest the potential application of UV-LEDs as promoter of different photochemical and photocatalytic processes, which are able to enhance disinfection in particular cases, such as the aquaculture industry., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Meeting the recent biological standards established by the Ballast Water Management Convention requires the application of ballast water treatment systems; ultraviolet irradiation is a frequently used option. However, organisms can repair the damage caused by ultraviolet irradiation primarily with photo-repair mechanisms that are dependent on the availability of light. The objective of this study is to quantify the impact of dark storage following ultraviolet irradiation on the viability of the microalgae Tetraselmis suecica. Results showed that one day of dark storage after ultraviolet irradiation enhanced the inactivation rate by 50% with respect to the absence of dark storage and increased up to the 84% with five days of dark storage. These results are consistent with photorepair, mostly in the first two days, prevented in the dark. The dose required to inactivate a determined ratio of organisms was correlated with the length of the dark post-treatment according to an inverse proportional function. This correlation may help to optimize the operation of ultraviolet ballast water treatment systems. Further, the results show that growth assays can detect organisms that are capable of repair after treatment with UV., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Over the years, industrial activities that generate high salinity effluents have been intensifying; this has relevant potential for causing organic and microbiological pollution which damages both human and ocean health. The development of new regulations, such as ballast water convention, encourage the development of treatment systems that can be feasible for treating seawater effluents. Accordingly, an approach based on the UV activation of persulfate salts has been assessed. In this scenario, two different persulfate sources (S 2 O 8 2- and HSO 5 - ) were evaluated under UV-C irradiation for disinfection purposes. An optimization process was performed with low chemical doses (<1 mM). In order to extensively examine the applicability on seawater, different water matrices were tested as well as different microorganisms including both fecal and marine bacteria. An enhancement of UV-inactivation with the addition of persulfate salts was achieved in all cases, kinetic rate constant has been accelerated by up to 79% in seawater. It implies a UV-dose saving up to 45% to achieve 4-log reductions. Best efficiencies were obtained with [HSO 5 - ] = 0.005 mM and [S 2 O 8 2- ] = 0.5 mM. Higher effectiveness was obtained with the use of HSO 5 - due to its low stability and interaction with chloride. Also, different responses were obtained according to the specific microorganisms by achieving faster disinfection in Gram-negative than in Gram-positive bacteria, the sensitivity observed was Vibrio spp. > E. coli > E. faecalis ≈ Marine Heterotrophic Bacteria. With an evaluation of regrowth after treatment, greater cell damage was detected with the addition of persulfate salts. The major ability of regrowth for marine bacteria encourages the use of a residual disinfectant after disinfection processes., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

To prevent the worldwide spread of invasive aquatic species, the ballast water of ships may be disinfected with either physical or chemical treatment systems. Excess chemicals, such as chlorine, are neutralized before the ballast water can be discharged. Unfortunately, disinfection byproducts (DBPs) formed during treatment are not neutralized and remain potentially toxic. In this study, DBPs obtained from land-based tests of seven different ballast water treatment systems (BWTSs) have been statistically analyzed. Effect of operational factors (treatment type, holding time, source of carbon and active substance dosages) and environmental variables (salinity, pH, temperature, organic matter) were related to the formation of DBPs, such as trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs) and aldehydes. THMs and HAAs were the groups with major occurrences and concentrations detected in all BWTSs. Treatment type and source of carbon were the operational factors with major significance on DBP production, especially in chlorination systems. Salinity is the main variable determining DBP composition, as it differs between brominated-DBPs and chlorinated-DBPs. Concentration and type of organic matter (dissolved and particulate) have also a significant influence on the formation of total DBPs. According to the specific group of DBPs, some factors get significance. For instance, THMs are significantly affected by pH, and the production of aldehydes correlates positively with oxidant dose., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The development of advanced photochemical processes has experienced the emergence of a promising alternative for water disinfection, different from traditional methods. The applicability has primarily been investigated in drinking and wastewater; however, new challenges related to microbiological control in marine waters necessitate evaluating the applicability of this process in such water matrices. In this study, the efficacy of persulfate (PDS) activated with UV-light against E. faecalis has been tested on the bench scale. Firstly, optimization of the different PDS concentrations (1-10 mM) and exposure times (0-5 min) was performed in distilled water. 1 mM of PDS was selected as the best dosage within the range tested. Secondly, in order to evaluate the effects of different inorganic compounds usually found in natural waters, the efficiency of the UV/PDS system was tested in three different matrices: mineral water, saltwater, and marine saltwater. Finally, different bacteria were evaluated in consortium (E. coli + E. faecalis), suggesting the same inactivation level independently on the bacterial groups and structures. The results suggest that PDS is an attractive alternative to other photochemical processes currently in use for seawater treatment and this application deserved further research.

Increasing concerns have accelerated the development of international regulations and methods for ballast water management to limit the introduction of non-indigenous species. The transport of microorganisms with ballast water has received scientific attention in recent years. However, few studies have focused on the importance of organisms smaller than 10 μm in diameter. In this work, we review the effects of ballast water transport, disinfection, and the release of microorganisms on ecosystem processes with a special focus on heterotrophic bacteria. It is important to evaluate both direct and indirect effects of ballast water treatment systems, such as the generation of easily degradable substrates and the subsequent regrowth of heterotrophic microorganisms in ballast tanks. Disinfection of water can alter the composition of bacterial communities through selective recolonization in the ballast water or the recipient water, and thereby affects bacterial driven functions that are important for the marine food web. Dissolved organic matter quality and quantity and the ecosystem status of the treated water can also be affected by the disinfection method used. These side effects of disinfection should be further investigated in a broader context and in different scales (laboratory studies, large-scale facilities, and on the ships)., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

Cruise ship wastewater discharges are pollution sources towards the marine environment that are poorly characterized. In this study, wastewater samples from cruise ships have been obtained during repair works in a shipyard. Different organic pollutants have been analyzed and their concentrations were similar to those in urban wastewaters for pharmaceuticals and fragrances, but higher for UV filters and PAHs. For the first time, cypermethrin, a pesticide highly toxic towards aquatic species, was found at relevant concentrations (>1 µg L^-1). The faecal microorganisms were for all parameters higher than 10^4 CFU 100 mL^ - 1, which together with the presence of antibiotic compounds in wastewater (e.g., triclosan), could potentially lead to the generation of antibiotic resistance bacteria (ARB). The historical position of cruise ships, determined from the Automatic Identification System (AIS), were used to define the time ships were underway, at port, or in repair. From ship's passenger and crew load, and from estimates of discharges the total volume of wastewater produced by these ships (371,000 m^3 year^-1) and the average flow (0.15 ± 0.03 m^3crew^-1 day^-1) were calculated., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The importance of seawater treatment in order to avoid microbiological pollution related to aquaculture or ballast water management has increased during the last few years. Bacterial indicators used for the evaluation of different disinfection treatments are usually related with both waste and drinking water, these standards are not usual microorganisms found in seawater. Thus, it is thought necessary to study the behavior of different marine-specific organisms in regard to improve the disinfection processes in seawater. In this study, three different bacteria have been selected among major groups of bacterial community from marine waters: two water-associated, Roseobacter sp. and Pseudomonas litoralis, and one sediment-associated, Kocuria rhizophila. A kinetic inactivation model together with a post-treatment growth tendency has been obtained after the application of UV-C and UV/H 2 O 2 processes. According to the first kinetic rate constant, different responses were obtained for the different bacterial groups. Once the treatment was applied, modeling of growth curves revealed high recover within the first 3 days after treatment, even when UV/H 2 O 2 was applied. This study introduces a sensitivity index, in which results show different levels of resistance for both treatments, being Roseobacter sp. the most sensitive bacteria, followed by P. litoralis and K. rhizophila.

Seawater treatment is increasingly required due to industrial activities that use substantial volumes of seawater in their processes. The shipping industry and the associated management of a ship's ballast water are currently considered a global challenge for the seas. Related to that, the suitability of an Electrochemical Advanced Oxidation Process (EAOP) with Boron Doped Diamond (BDD) electrodes has been assessed on a laboratory scale for the disinfection of seawater. This technology can produce both reactive oxygen species and chlorine species (especially in seawater) that are responsible for inactivation. The EAOP was applied in a continuous-flow regime with real seawater. Natural marine heterotrophic bacteria (MHB) were used as an indicator of disinfection efficiency. A biphasic inactivation kinetic model was fitted on experimental points, achieving 4-Log reductions at 0.019 Ah L -1 . By assessing regrowth after treatment, results suggest that higher bacterial damages result from the EAOP when it is compared to chlorination. Furthermore, several issues lacking fundamental understanding were investigated such as recolonization capacity or bacterial community dynamics. It was concluded that, despite disinfection processes being effective, there is not only a possibility for regrowth after treatment but also a change on bacterial population diversity produced by the treatment. Finally, energy consumption was estimated and indicated that 0.264 kWh·m -3 are needed for 4.8-Log reductions of MHB; otherwise, with 0.035 kWh·m -3 , less disinfection efficiency can be obtained (2.2-Log red). However, with a residual oxidant in the solution, total inactivation can be achieved in three days., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Water contained on ships is employed in the majority of activities on a vessel; therefore, it is necessary to correctly manage through marine water treatments. Among the main water streams generated on vessels, ballast water appears to be an emerging global challenge (especially on cargo ships) due to the transport of invasive species and the significant impact that the ballast water discharge could have on ecosystems and human activities. To avoid this problem, ballast water treatment must be implemented prior to water discharge in accordance with the upcoming Ballast Water Management Convention. Different UV-based treatments (photolytic: UV-C and UV/H 2 O 2 , photocatalytic: UV/TiO 2 ), have been compared for seawater disinfection. E. faecalis is proposed as a biodosimeter organism for UV-based treatments and demonstrates good properties for being considered as a Standard Test Organism for seawater. Inactivation rates by means of the UV-based treatments were obtained using a flow-through UV-reactor. Based on the two variables responses that were studied (kinetic rate constant and UV-Dose reductions), both advanced oxidation processes (UV/H 2 O 2 and photocatalysis) were more effective than UV-C treatment. Evaluation of salinity on the processes suggests different responses according to the treatments: major interference on photocatalysis treatment and minimal impact on UV/H 2 O 2 ., (Copyright © 2016 Elsevier B.V. All rights reserved.)