Photodegradation of halogenated organic disinfection by-products: Decomposition and reformation.

In this study, the photodegradation of 33 different DBPs (trihalomethanes, haloacetic acids, haloacetaldehydes, and haloacetonitriles) and TOX with low pressure UV light and the subsequent reformation of DBPs with chlorine and monochloramine were investigated. Results indicated that photodegradation followed the order of TOI > TOBr > TOCl, and treated surface water with low SUVA background did not impact the photodegradation of highly UV susceptible DBPs such as triiodomethane (TIM), diiodobromomethane (DIBM), tribromomethane (TBM). The mass balance results of chloride, bromide and iodide showed that the main photodegradation mechanism of TOBr and TOI was dehalogenation supported by halide releases (i.

Activated carbon and organic matter characteristics impact the adsorption of DBP precursors when chlorine is added prior to GAC contactors.

Pre-chlorination (i.e. dosing chlorine prior to granular activated carbon (GAC) contactors) was recently introduced as a promising method to reduce the formation of disinfection byproducts (DBPs).

Two years of post-wildfire impacts on dissolved organic matter, nitrogen, and precursors of disinfection by-products in California stream waters.

We investigated the effects of two California wildfires (Rocky and Wragg Fires, 2015) compared to an unburned reference watershed on water quality, dissolved organic matter (DOM), and precursors of disinfection by-products (DBPs) for two years' post-fire. The two burned watersheds both experienced wildfires but differed in the proportion of burned watershed areas. Burned watersheds showed rapid water quality degradation from elevated levels of turbidity, color, and suspended solids, with greater degradation in the more extensively burned watershed.

Effect of bromide on NDMA formation during chloramination of model precursor compounds and natural waters.

In this work, we investigated the effect of bromide ion (Br) on NDMA formation using model precursor compounds, wastewater effluents and surface waters. Previous studies showed that Br reacts with chloramines and forms bromochloramine, a reactive compound responsible for NDMA formation enhancement. Some limitations of those studies were the highest Br concentrations used, and the limited number of precursors considered.

Selective removal of bromide and iodide from natural waters using a novel AgCl-SPAC composite at environmentally relevant conditions.

The removal of bromide (Br) and iodide (I) from source waters mitigates the formation of brominated and iodinated disinfection by-products (DBPs), which are more toxic than their chlorinated analogues. In this study, we report on our recently developed environmental-friendly method for the preparation of novel silver chloride/superfine activated carbon composite (AgCl-SPAC) to rapidly and selectively remove Br and I from surface waters. The material characteristics were tracked, before and after treatment, using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS) spectroscopies.