Effect of UV treatment on DBP formation

Abstract

This study—s objective was to investigate the effect of ultraviolet (UV) treatment on the subsequent formation of regulated and unregulated disinfection by‐products (DBPs). UV treatment of two sets of waters did not substantially change the waters— tendency to form trihalomethanes, haloacetic acids, or total organic halogen under the conditions of these tests. Evidence was found of small reductions in the formation of these DBPs, but the decreases did not exceed 10%. Formation of chloropicrin and 1,1,1‐trichloropropanone increased as a result of medium‐pressure UV treatment but remained at levels well below those of the regulated DBPs. Low‐pressure UV did not cause any detectable increase in chloropicrin formation. The authors propose that photonitration leads to the formation of new nitroorganics during UV treatment and these form halonitromethanes during subsequent chlorination. It is recommended that the effects of UV treatment on nonregulated DBPs be considered as new UV drinking water systems are brought on line.

The formation of haloacetamides and other disinfection by-products from non-nitrogenous low-molecular weight organic acids during chloramination

“…The details of the HAcAm analyses are presented elsewhere [17], and are summarized in the supplementary material (Table S1) Formed DBP molar concentration DBP yield 100% Initial LMWOA molar concentration   Figure 1 shows the yields of four C-DBPs (DCM, TCM, DCAA, and TCAA) formed from the chloramination of the seven LMWOAs ( Table 1). As can be seen, the yields of TCM, DCAA and TCAA increased with increasing the contact time from 6 h to 72 h, while the formation of DCM increased from 6 h to 24 h, before subsequently decreasing from 24 h to 72 h. Thus DCM was not the end product of these seven LMWOAs during chloramination, whereas TCM, DCAA and TCAA were relatively stable under the experimental conditions used, which is in agreement with the previous studies [7,38].…”

Formation of halogenated C-, N-DBPs from chlor(am)ination and UV irradiation of tyrosine in drinking water

“…DBPs (e.g., CF) after UV exposure and subsequent chlorination (Liu et Reckhow et al, 2010). However, in another recent study, there was an impact 314 from medium pressure UV whereas there was no impact from low pressure UV (Reckhow 315 et al, 2010), and it was a low pressure system that was used in this study.…”

Precursors of nitrogenous disinfection by-products in drinking water––A critical review and analysis

“…The propensity for pre-ozonation to enhance HNM formation (with nitrate present) is presumably due to a similar nitration mechanism as inferred for resorcinol. Similarly, increased chloropicrin formation following medium pressure UV irradiation has been linked to photonitration of aromatic NOM functionalities [15]. Various hydrophilic NOM surrogates, including amino acids, amino sugars, primary amines (monomethylamine) and nucleic acids (cytosine and adenine) formed insignificant yields of chloropicrin following chlorination alone [20,27,43], while nitrite, pH and bromide had a negligible effect on yields from amino acids and amino sugars [43].…”

“…Journal publications only, search term: 'potable water' or 'drinking water' plus N-DBP group/species. chlorination increases chloropicrin [14] and even medium pressure UV disinfection prior to chlorination has recently been reported to slightly enhance halonitromethane formation [15,16]. Secondly, water providers are increasingly treating water sources which are polluted with algae and municipal wastewater, both key sources of dissolved organic nitrogen (DON) and in turn N-DBP precursors.…”