Application of a novel polarity method for the characterization of natural organic matter during water treatment

Abstract

The changes in polarity of natural organic matter (NOM) across a pilot-scale conventional water treatment plant with pre-ozonation and biofiltration were analyzed using the polarity rapid assessment method (PRAM). PRAM is a novel method developed for the characterization of the polarity of NOM in environmental samples. Characterization was accomplished by monitoring UV absorbance (UVA) at 254 nm. Under ambient conditions, the NOM was characterized as highly anionic (.50%), with limited hydrophobic (10 -25%) and hydrophilic (0-10%) domains. Results showed temporal variations in the polarity of NOM entering the pilot plant. These differences were ascribed to changes in water blend and variability in NOM characteristics. Changes in NOM chemistry were also observed as the organics passed through the treatment process. Ozonation decreased the hydrophobicity and increased the polarity of NOM, confirming results from previous research utilizing resin fractionation methods. Coagulation, flocculation and biofiltration resulted in the decrease of the hydrophobic and hydrophilic character of the chromophoric NOM.However, these polarity changes varied during the pilot plant run, suggesting a more precise evaluation of NOM through unit operations is warranted.

Nitrosamine precursor and DOM control in an effluent‐affected drinking water

“…Even the DOC with MW of 1-3 kD was removed at significant rates (~ 40%). It is expected that the low-MW fraction could be more hydrophilic (Chen et al, 2011;Gerringer et al, 2009;Rosario-Ortiz et al, 2009;Xu et al, 2007). The removal mechanism for low-MW DOM by the GAC may also have been attributable to the biodegradability of the smaller molecules (Amy et al, 1992).…”

Effect of Wildfires on Physicochemical Changes of Watershed Dissolved Organic Matter

“…Leachate pH and conductivity were measured by Accumet AP85 after 30 minutes of agitation, and upon completion of the 48-hour agitation (Fisher Scientific, Waltham, Massachusetts). Dissolved organic carbon (APHA et al, 2005), UV absorbance (UVA 254 ) (APHA et al, 2005), UF (Revchuk and Suffet, 2009), PRAM (Rosario-Ortiz et al, 2009), and EEM fluorescence analyses (Chen et al, 2003), were subsequently conducted on the bulk and fractionated samples. Leached samples were stored at 4 8C to prevent biodegradation.…”

“…Polarity. Solid phase extraction (SPE) cartridges (Grace Davison, Columbia, Maryland) with different sorbents were used in parallel to determine the adsorption of DOM: C18 for hydrophobic fraction; Diol for hydrophilic fraction and NH 2 ,a weak anion exchanger, for negatively charged fraction (Rosario-Ortiz et al, 2009). Characterization of PRAM was conducted on leachates diluted to 9 mg-C/L using additional buffer solution, maintaining the original ionic strength (Rosario-Ortiz et al, 2007).…”

“…Post-fire ash and nonburned control vegetation samples were collected and leached to characterize the differences between the fire-released and unburned DOM. The DOM size distribution and polarity were characterized by ultrafiltration (UF) fractionation (Revchuk and Suffet, 2009), and the polarity rapid assessment method (PRAM) (Rosario-Ortiz et al, 2009), respectively. Fluoroactive constituents of organic matter, a ubiquitous component of DOM (Baker, 2001), were characterized by excitation-emission matrix (EEM) fluorescence spectroscopy to determine the origin and types of DOM (Chen et al, 2003).…”

“…Ultrafiltration size characterization (Revchuk and Suffet, 2009), PRAM methodology for evaluation of polarity (Rosario-Ortiz et al, 2009), and fluorescence spectroscopy for evaluation of the origin of DOM (Chen et al, 2003), have never been implemented for the study of wildfire-affected waters. Therefore, this study applies novel quantitative analytical techniques for the characterization of wildfire effects on the characteristics of wildfire-generated DOM.…”