[Concentration Variation and Removal of Amino Acids in Typical Drinking Sources in the South of China].

Amino acids are the main components of nitrogenous organic matter in surface water. In order to reveal the concentration variation and removal of amino acids in reservoirs water, the concentration variation of the twenty common amino acids for three main reservoirs' water in a typical southern city of China was monitored between May and October in the year of 2015 by HPLC, and the space distribution and change trend of the twenty amino acids were analyzed. In addition, the removal of the twenty amino acids was also studied by different water treatment processes. The results showed that the amino acids contents and composition were different among the three reservoirs. Aspartic acid, cysteine and leucine were the main amino acids for the three reservoirs. Besides, there was no obvious seasonal variation of amino acids content for reservoir C. However, the concentration of amino acids in autumn was higher than that in summer. Coagulation and sedimentation were main units for the removal of amino acids in conventional and BAC-UF processes while O3 oxidation was the main unit in O3-BAC process. 94.42%, 66.04% and 49.75% of total amino acids contents were removed by the conventional, BAC-UF and O3-BAC processes, respectively.

[Influence of Chemical Pre-oxidation on Chloral Hydrate Formation of Threonine].

The influences of different chemical pre-oxidants, including sodium hypochlorite (NaClO), chlorine dioxide (ClO2), permanganate (KMnO4), hydrogen peroxide (H2O2), ozone (O3) and ozone/hydrogen peroxide (O3/H2O2), on chloral hydrate (CH) formation were studied for threonine that has the highest special chloral hydrate formation potential (SCHFP). Suitable pre-oxidants and corresponding optimal doses were determined to provide guidance for controlling chloral hydrate (CH) formation during drinking water treatment. The results indicated that the pre-oxidants that could decrease CH formation for one day incubation time (CH1d) were H2O2, ClO2, KMnO4 and NaClO, and the corresponding suitable doses were 3, 0.5, 0.6 and 0.5 mg·L-1, and the corresponding CH1d removal rates were 61.54%, 47.63%, 29.77% and 10.94%, respectively. The pre-oxidants that could decrease CH formation potential (CHFP) were KMnO4, NaClO, H2O2 and ClO2, and the corresponding suitable doses were 0.6 mg·L-1, 0.5 mg·L-1, 3 mg·L-1 and 0.5 mg·L-1, and the corresponding CHFP removal rates were 41.01%, 33.38%, 8.36% and 2.40%, respectively. In addition, O3 and O3/H2O2 were not suitable for controlling CH in the conventional treatment process because they could increase CH1d and CHFP.