Decomposition of two haloacetic acids in water using UV radiation, ozone and advanced oxidation processes.

The decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), from water was studied by means of single oxidants: ozone, UV radiation; and by the advanced oxidation processes (AOPs) constituted by combinations of O(3)/UV radiation, H(2)O(2)/UV radiation, O(3)/H(2)O(2), O(3)/H(2)O(2)/UV radiation. The concentrations of HAAs were analyzed at specified time intervals to elucidate the decomposition of HAAs. Single O(3) or UV did not result in perceptible decomposition of HAAs within the applied reaction time.

[Effect of DO distribution on contaminated urban stream water treatment performance in constructed wetland].

We evaluated the effect of dissolved oxygen (DO) on the performance of two pilot-scale constructed wetlands in treating contaminated water from an urban stream. The aim of this study was to investigate a more effective DO distribution in contaminated stream water treatment wetland that may aid future constructed wetland design effort. The results show poor natural aeration condition and inadequate DO in wetland directly result in the deterioration of effluent water quality.

[Analysis of haloacetic acids in drinking water by gas chromatography-mass spectrometry].

Based on liquid-liquid micro-extraction and acidic methanol derivatization methods from EPA Method 552.3, a gas chromatographic-mass spectrometric (GC-MS) method has been studied for determining haloacetic acid (HAAs) in drinking water using ultrapure water instead of methyl tert-butyl ether (MTBE) as solvent for preparing standard stock solution. The results showed that the peaks of 1,2-dibromo propane (internal standard) and HAAs were separated very well.

[Adsorption performance of haloacetic acids onto 5 GACs from water].

Adsorption performance of 5 GACs were compared on two abundant haloacetic acids (HAAs) as disinfection by-products (dichloroacetic acid and trichloroacetic acid). The adsorption behaviours of the two HAAs were well correlated with Langmuir equation. When the two HAAs co-existed, trichloroacetic acid tended to be adsorbed more easily.