Effects of physicochemical parameters of water on byproduct formation during electrolysis of ballast water

Abstract

Introduction: Disinfection byproducts (DBPs) generated during ballast water treatment using active substances have gained increasing interest owing to their potential impact on the marine environment. This study aimed to investigate the occurrence and distribution of DBPs, which are secondary products generated during electrolysis, using land-based tests. Methods: DBP levels were compared under various water conditions, including chloride and bromide ion compositions, hold time, and organic matter-related parameters. Results: After electrolysis, trihalomethane (THM) and haloacetic acid (HAA) levels increased from day 0 to day 5 under all salinities, whereas haloacetonitrile (HAN) level decreased. THMs were found to be the most dominant DBP group, followed by HAAs and HANs. In marine water and brackish water, brominated DBPs were dominant owing to high levels of bromide ions, while chlorinated DBP concentrations were relatively high in fresh water. Discussion: After electrolysis, the specific ultraviolet absorption of the treated water was >4, indicating a high likelihood of generating carbonaceous DBPs such as THMs and HAA. These findings contribute to a better understanding of the general mechanisms through which physicochemical factors affect the formation of DBPs during electrolysis treatment of ballast water. This understanding is valuable in addressing issues related to the treatment and release of treated ballast water into the marine environment, which is an emerging environmental concern.