Simultaneous time-resolved inorganic haloamine measurements enable analysis of disinfectant degradation kinetics and by-product formation.

We demonstrate the application of proton transfer time-of-flight mass spectrometry (PTR-TOF-MS) in monitoring the kinetics of disinfectant decay in water with a sensitivity one to three orders of magnitude greater than other analytical methods. Chemical disinfection inactivates pathogens during water treatment and prevents regrowth as water is conveyed in distribution system pipes, but it also causes formation of toxic disinfection by-products. Analytical limits have hindered kinetic models, which aid in ensuring water quality and protecting public health by predicting disinfection by-products formation.

Participant-collected household dust for assessing microorganisms and semi-volatile organic compounds in urban homes.

Dust samples collected by researchers and study participants from 43 U.S. urban homes were analyzed and compared to evaluate the feasibility of using participant-collected samples to assess indoor environmental exposures.

Apparent Reactivity of Bromine in Bromochloramine Depends on Synthesis Method: Implicating Bromine Chloride and Molecular Bromine as Important Bromine Species.

The chloramination of bromide containing waters results in the formation of bromine containing haloamines: monobromamine (NHBr), dibromamine (NHBr), and bromochloramine (NHBrCl). Many studies have directly shown that bromamines are more reactive than chloramines in oxidation and substitution reactions with organic water constituents because the bromine atom in oxidants is more labile than the chlorine atom. However, similar studies have not been performed with NHBrCl.

Role of Carbonate Species on General Acid Catalysis of Bromide Oxidation by Hypochlorous Acid (HOCl) and Oxidation by Molecular Chlorine (Cl).

Kinetic models for disinfectant decay and disinfection byproduct (DBP) formation are necessary for predicting water quality from the treatment plant to the tap. A kinetic model for conditions relevant to chloramine disinfection of drinking water (pH 6-9 and carbonate-buffered) was developed to simulate incomplete bromide (Br) oxidation during short prechlorination periods because it is the first step in a complex system of reactions that leads to disinfectant loss and DBP formation. Hypochlorous acid and molecular chlorine were the free chlorine species relevant to Br oxidation, and Cl hydrolysis and formation reactions were necessary to accurately simulate Cl concentrations instead of assuming equilibrium.

Water Treatment: Are Membranes the Panacea?

Alongside the rising global water demand, continued stress on current water supplies has sparked interest in using nontraditional source waters for energy, agriculture, industry, and domestic needs. Membrane technologies have emerged as one of the most promising approaches to achieve water security, but implementation of membrane processes for increasingly complex waters remains a challenge. The technical feasibility of membrane processes replacing conventional treatment of alternative water supplies (e.