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Inputs of disinfection by-products to the marine environment from various industrial activities: Comparison to natural production

Jin Jiang, Urs von Gunten

Oxidative treatment of seawater in coastal and shipboard installations is applied to control biofouling and/or minimize the input of noxious or invasive species into the marine environment. This treatment allows a safe and efficient operation of industrial installations and helps to protect human health from infectious diseases and to maintain the biodiversity in the marine environment. On the downside, the application of chemical oxidants generates undesired organic compounds, so-called disinfection by-products (DBPs), which are discharged into the marine environment. This article provides an overview on sources and quantities of DBP inputs, which could serve as basis for hazard analysis for the marine environment, human health and the atmosphere. During oxidation of marine water, mainly brominated DBPs are generated with bromoform (CHBr3) being the major DBP. CHBr3 has been used as an indicator to compare inputs from different sources. Total global annual volumes of treated seawater inputs resulting from cooling processes of coastal power stations, from desalination plants and from ballast water treatment in ships are estimated to be 470-800 x 109 m(3), 46 x 10(9) m(3) and 3.5 x 10(9) m(3), respectively. Overall, the total estimated anthropogenic bromoform production and discharge adds up to 13.5-21.8 x 10(6) kg/a (kg per year) with contributions of 11.8-20.1 x 10(6) kg/a from cooling water treatment, 0.89 x 10(6) kg/a from desalination and 0.86 x 10(6) kg/a from ballast water treatment. This equals approximately 2-6% of the natural bromoform emissions from marine water, which is estimated to be 385-870 x 10(6) kg/a.

PERGAMON-ELSEVIER SCIENCE LTD2022

Enhanced transformation of sulfonamide antibiotics by manganese(IV) oxide in the presence of model humic constituents

Jin Jiang, Jun Ma, Yang Song, Urs von Gunten

In this study, a manganese(IV) oxide-mediator (MnO2-mediator) system for the abatement of sulfonamide antibiotics was evaluated. Two simple model humic constituents, syringaldehyde (SA) and acetosyringone (AS), could promote the transformation of sulfonamides at pH 5-8. Two additional potential mediators, tannic acid and 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonate (ABTS), had negligible enhancement on the transformation of sulfonamides by MnO2. The enhancing effect was attributed to the reaction of the oxidized mediator (i.e., phenoxy radical or benzoquinone-like compounds) produced from the oxidation of the mediators by MnO2 with SMX. Thereby cross-coupling products from sulfamethoxazole (SMX) with oxidized SA were formed in the MnO2-SA system, which was confirmed by liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry. Coexisting metal ions (i.e., Ca(II), Mg(II) and Mn(II)) showed inhibitory effects in the order of Mn(II)> Ca(II)> Mg(II). For repetitive runs of the MnO2-SA-SMX system, MnO2 lost its oxidative capacity due to the sorption of Mn(II) on the reactive sites of the MnO2 surface. A full regeneration of partially deactivated MnO2 by oxidation of the sorbed Mn(II) with Mn(VII) could be achieved. (C) 2019 Elsevier Ltd. All rights reserved.

PERGAMON-ELSEVIER SCIENCE LTD2019