Chlorination or monochloramination: Balancing the regulated trihalomethane formation and microbial inactivation in marine aquaculture waters
MetadataShow full item record
© 2017 Disinfection methods like chlorination are increasingly used to sanitize the water, equipment, tools and surfaces in aquaculture facilities. This is to improve water quality, and to maintain a hygienic environment for the well-being of aquatic organisms. However, chlorination can result in formation of regulated disinfection byproducts (DBPs) that can be carcinogenic and toxic. This study aims to evaluate if an optimal balance can be achieved between minimal regulated DBP formation and effective microbial inactivation with either chlorination or monochloramination for application in the Red Sea aquaculture waters. Upon chlorination, the concentration of total trihalomethanes (THMs), primarily bromoform, exceeded the regulatory limit of 80 µg/L even at the lowest tested concentration of chlorine (1 mg/L) and contact time (1 h). Comparatively, regulated THMs concentration was only detectable at 30 µg/L level in one of the three sets of monochloraminated marine aquaculture waters. The average log reduction of antibiotic-resistant bacteria (ARB) by chlorine ranged from 2.3-log to 3.2-log with different contact time. The average log reduction of ARB by monochloramine was comparatively lower at 1.9 to 2.9-log. Although viable Staphylococcus aureus was recovered from monochloraminated samples as opposed to chlorinated samples, the abundance of S. aureus was not high enough to result in any significant microbial risks. Both chlorination and monochloramination did not provide any significant improvement in the reduction of antib iotic resistance genes (ARGs). This study demonstrates that a systematic evaluation is needed to determine the optimal disinfectant required to balance both microbial and chemical risks. Compared to chlorine, monochloramine may be a more appropriate disinfection strategy for the treatment of aquaculture effluents prior to discharge or for recirculatory use in the aquaculture facility.
Showing items related by title, author, creator and subject.
Toxicity evaluation of synthetic waters based on Br-Cl-I-THMs formation during the chlorine/ammonia processAllard, Sebastian; Tan, J.; Charrois, Jeffrey; Joll, C.; Heitz, A.; Von Gunten, Urs (2014)Monochloramine (NH2Cl) is commonly used as an alternative to chlorine for disinfection because it is less reactive with the organic matrix, therefore forms less regulated DBPs and leads to a more stable residual. However, ...
Bioanalytical assessment of the formation of disinfection byproducts in a drinking water treatment plantNeale, P.; Antony, A.; Bartkow, M.; Farre, M.; Heitz, Anna; Kristiana, Ina; Tang, J.; Escher, B. (2012)Disinfection of drinking water is the most successful measure to reduce water-borne diseases and protect health. However, disinfection byproducts (DBPs) formed from the reaction of disinfectants such as chlorine and ...
Breakpoint chlorination and free-chlorine contact time: Implications for drinking water N-nitrosodimethylamine concentrationsCharrois, Jeffrey; Hrudey, S. (2007)North American drinking water utilities are increasingly incorporating alternative disinfectants, such as chloramines, in order to comply with disinfection by-product (DBP) regulations. N-Nitrosodimethylamine (NDMA) is a ...