Maintenance of monochloramine concentration during water disinfection is important to ensure the microbial safety of drinking water. The decay of monochloramine always occurs and some substances present in the water can accelerate this process. Copper often exists in ionic form in water, but the effect of Cu(II) on the decomposition of monochloramine is largely unknown. In this paper, a series ...

Previous studies modeled NDMA formation during chlorine disinfection as arising from the oxidation of an unsymmetrical dimethylhydrazine intermediate formed from the reaction of monochloramine and dimethylamine. However, chlorination of wastewater effluents indicated that this mechanism could not account for a significant portion of the observed NDMA formation. Laboratory studies indicated that...

The rate of Cryptosporidium parvum inactivation decreased with decreasing temperature (1-20 degrees C) for ozone and for monochloramine applied alone as well as after pre-treatment with ozone. Synergy was observed at all temperatures studied for the ozone/monochloramine sequential disinfection scheme. The synergistic effect was found to increase with decreasing temperature. The inactivation rat...

This paper describes the characterization and evaluation of various RO/NF membranes for the treatment of seasonally brackish surface water with high organic contents (TOC ≈21 mg/L). Twenty commercially available RO and NF membranes were initially evaluated by performing controlled bench-scale flat-sheet tests and surface characterization. Based on the results, four low pressure RO membranes wer...

Currents through sodium channels of neuroblastoma cells were measured using patch technique in outside-out configuration. Scorpion toxin (ScTX) produced 3 to 4 fold prolongation of mean open time and increased number of reopenings. The mean open times showed slow fluctuations around some average values. The distribution of channel open times for ScTX-modified channels required more than one exp...

The presence and transformation of volatile halogenated organics in wastewaters after treatment with monochloramine have been examined using an Agilent 7890A GC coupled to an Agilent 7700x ICP-MS. The element-specific bromine and iodine content in this diverse set of organic species have been determined using compound-independent calibrations (CICs) that are based on the elemental responses obt...