Two natural waters were fortified with various levels of bromide or iodide ions (0-30 microM) and chlorinated in the laboratory to study the impact of bromide and iodide ions on the formation and speciation of disinfection byproducts. Trihalomethanes (THMs), haloacetic acids (HAAs), total organic halogen (TOX), and its halogen-specific fractions total organic chlorine (TOCl), bromine (TOBr), and iodine (TOI), were measured in this work. The molar yields of THMs and HAAs increased as the initial bromide concentration increased. No significant change in TOX concentration was found for varying bromide concentrations. However, TOX concentrations decreased substantially with increasing initial iodide concentrations. At higher levels of bromide, there was a decreasing level of unknown TOX and unknown TOCl but an increasing level of unknown TOBr. The extent of iodine substitution was much lower than that of bromine substitution when comparing identical initial concentrations because a substantial amount of iodide was oxidized to iodate by chlorine. The tendency toward iodate formation resulted in the unusual situation where higher chlorine doses actually caused reduced levels of iodinated organic byproducts. Quantitative assessment of the results of this study showed a good agreement with kinetic data in the literature.

We present an autonomous driving research vehicle with minimal appearance modifications that is capable of a wide range of autonomous and intelligent behaviors, including smooth and comfortable trajectory generation and following; lane keeping and lane changing; intersection handling with or without V2I and V2V; and pedestrian, bicyclist, and workzone detection. Safety and reliability features include a fault-tolerant computing system; smooth and intuitive autonomous-manual switching; and the ability to fully disengage and power down the drive-by-wire and computing system upon E-stop. The vehicle has been tested extensively on both a closed test field and public roads.

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.

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