Effects of Pre-Oxidation on Haloacetonitrile and Trichloronitromethane Formation during Subsequent Chlorination of Nitrogenous Organic Compounds

Abstract

The reaction between organic matter and disinfectants leads to the formation of disinfection byproducts (DBPs) in drinking water. With the improvement of detection technology and in-depth research, more than 1000 kinds of DBPs have been detected in drinking water. Nitrogenous DBPs (N-DBPs) are more genotoxic and cytotoxic than the regulated DBPs. The main methods are enhanced coagulation, pretreatment, and depth technologies which based are on conventional technology. Amino acids (AAs) are widely found in surface waters and play an important role by providing precursors from which toxic nitrogenous disinfection by-products (N-DBPs) are generated in chlorinated drinking water. The formation of N-DBPs, including dichloroacetonitrile, trichloroacetonitrile, and trichloronitromethane (TCNM), was investigated by analyzing chlorinated water using ozone (OZ), permanganate (PM), and ferrate (Fe(VI)) pre-oxidation processes. This paper has considered the control of pre-oxidation over N-DBPs formation of AAs, OZ, PM, and Fe(VI) pre-oxidation reduced the haloacetonitrile formation in the downstream chlorination. PM pre-oxidation decreased the TCNM formation during the subsequent chlorination, while Fe(VI) pre-oxidation had no significant influence on the TCNM formation, and OZ pre-oxidation increased the formation. OZ pre-oxidation formed the lowest degree of bromine substitution during subsequent chlorination of aspartic acid in the presence of bromide. Among the three oxidants, PM pre-oxidation was expected to be the best choice for reducing the estimated genotoxicity and cytotoxicity of the sum of the measured haloacetonitriles (HANs) and TCNM without bromide. Fe(VI) pre-oxidation had the best performance in the presence of bromide.

Detection of mecA positive staphylococcal species in a wastewater treatment plant in South Africa

“…This study confirmed the presence of staphylococci in the final effluent after chlorination. Due to its simple management, low cost, and high efficiency in eliminating microorganisms in wastewater treatment plants, chlorination purification method at the final/tertiary effluent phase was considered an effective disinfection method (Wang et al 2020 ; Collivignarelli et al 2021 ). However, in recent times, chlorination has proved to transmit antibiotic resistance genes (ARGs) in treated wastewaters (Ghernaout & Elboughdiri 2020 ; Collivignarelli et al 2021 ).…”

Effective Control of N-Nitrosamines Formation from Water by Layered Double Oxide/Biochar Spheres: Research on the Adsorption of Precursors

“…16−18 Preoxidation with ozone, permanganate, ferrate, peroxide, etc., is capable of reducing NDMA formation by deactivating NDMA precursors. 19,20 However, it may promote the formation of other associated DBPs. 5 Adsorption is promising for the treatment of N-nitrosamine precursors due to its simplicity and good removal ability.…”

“…However, N -nitrosamine and its precursors are poorly rejected by the common ultrafiltration process in water plants, except for some reported reverse osmosis membranes. , In addition, research has concluded that common coagulation treatment could hardly eliminate the formation of NDMA . Precursors such as DMA, trimethylamine, and amine-based pharmaceuticals were shown to be biodegradable, while NDMA formation potentials were reduced by 10%–98% during the activated sludge process. − Preoxidation with ozone, permanganate, ferrate, peroxide, etc., is capable of reducing NDMA formation by deactivating NDMA precursors. , However, it may promote the formation of other associated DBPs . Adsorption is promising for the treatment of N -nitrosamine precursors due to its simplicity and good removal ability. − For example, activated carbon, which is widely used in drinking water treatment plants, has a considerable removal effect on N -nitrosamine precursors. − However, activated carbon exhibits poor performance against some precursors such as low molecular weight amines, and few research has demonstrated its adsorption selectivity, which can lead to unstable control of N-nitrosodimethylamine formation potential (NDMA-FP).…”

Comparison of nitrate formation mechanisms from free amino acids and amines during ozonation: a computational study

“…[1][2][3][4][5][6][7][8][9][10][11][12] However, nitrate as the endpoint product of ozonation of dissolved organic nitrogen (DON) has been found in epidemiological studies to be associated with methemoglobinemia, colorectal cancer, thyroid cancer, neuroepithelial brain tumours, and adverse health outcomes. [13][14][15][16][17][18] Recent research studies have demonstrated that nitrate could be a potential surrogate parameter for abatement of micropollutants, oxidant exposure, and characterizing oxidant-reactive DON during ozonation. 19 Accordingly, nitrate has attracted extensive attention for decades in the environmental eld especially in the ozonation of drinking water.…”