Overview of Monitoring Techniques for Evaluating Water Quality at Potable Reuse Treatment Facilities.

Needless to say, the safety of treated water for potable reuse must be definitively ensured. Numerous methods are available for assessing water quality; it's important to understand their challenges and limitations.

Fluorescence and Quenching Assessment (EEM-PARAFAC) of de Facto Potable Reuse in the Neuse River, North Carolina, United States.

The Neuse River, North Carolina, U.S., exemplifies a typical de facto potable reuse scenario, where drinking water sources are located downstream of treated wastewater effluent discharges. The study results imply that planned potable water reuse, whether in an indirect or direct potable reuse scenario, might provide better control over water quality than the status quo conditions. Using fluorescence excitation-emission matrix (EEM) measurements, anthropogenic influence of a wastewater treatment plant (WWTP) discharge was observed in samples near the location of drinking water treatment plant (WTP) intakes, eight or more miles downstream of the WWTP, implying that anthropogenic compounds were not fully removed or degraded by natural processes in this reach of the river. PARAllel FACtor (PARAFAC) analysis supported a two-component model of humic-like and nonhumic-like dissolved organic matter (DOM). A nonmodeled anthropogenic feature was also indicated. Significantly, the quenched fluorescence of humic-like DOM (static and/or dynamic quenching) by nonhumic-like DOM-previously demonstrated for probe molecules but first reported here in a natural/anthropogenic-influenced system-offers exciting insight into studies of humic/nonhumic interactions with important implications for pollutant fate and transport, sensing applications, and water treatment. A molecular spectroscopic explanation for dual fluorescing peaks in amino acids and humic substances is postulated.

Adsorption and aggregation properties of norovirus GI and GII virus-like particles demonstrate differing responses to solution chemistry.

The transport properties (adsorption and aggregation behavior) of virus-like particles (VLPs) of two strains of norovirus ("Norwalk" GI.1 and "Houston" GII.4) were studied in a variety of solution chemistries. GI.1 and GII.4 VLPs were found to be stable against aggregation at pH 4.0-8.0. At pH 9.0, GI.1 VLPs rapidly disintegrated. The attachment efficiencies (α) of GI.1 and GII.4 VLPs to silica increased with increasing ionic strength in NaCl solutions at pH 8.0. The attachment efficiency of GI.1 VLPs decreased as pH was increased above the isoelectric point (pH 5.0), whereas at and below the isoelectric point, the attachment efficiency was erratic. Ca(2+) and Mg(2+) dramatically increased the attachment efficiencies of GI.1 and GII.4 VLPs, which may be due to specific interactions with the VLP capsids. Bicarbonate decreased attachment efficiencies for both GI.1 and GII.4 VLPs, whereas phosphate decreased the attachment efficiency of GI.1, while increasing GII.4 attachment efficiency. The observed differences in GI.1 and GII.4 VLP attachment efficiencies in response to solution chemistry may be attributed to differential responses of the unique arrangement of exposed amino acid residues on the capsid surface of each VLP strain.

Norovirus removal and particle association in a waste stabilization pond.

The presence of norovirus (NoV) genogroup I (GI) and II (GII) was evaluated using real-time reverse transcription polymerase chain reaction (rRT-PCR) in the influent, two midtreatment locations, and final effluent of a three-pond serial waste stabilization pond system from December 2005 through June 2006. Additionally, influent and effluent samples were filtered through a cascade of three membrane filters with sequentially smaller pores to determine the size range of particles with which GI and GII were associated. NoV GI and GII removal occurs primarily in the third pond. Viruses were found on large settleable particles (retained on a 180 microm filter), on smaller suspended particles (retained on a 0.45 microm filter), on colloidal particles (retained on a positively charged 0.45 microm filter), and in the final filtrate. Both GI and GII in influent samples were found to be dominantly associated with particles smaller than 180 microm, thereby suggesting that particle settling is not the main virus removal mechanism in the waste stabilization pond system. On average, NoV detected in filtered effluent samples were associated with particles between 0.45 and 180 microm in diameter (47 and 67% of detected GI and GII, respectively). The presence of NoV GI and GII in the final filtrate of influent and effluent samples shows that positively charged membrane filters often used for viral concentration methods are not capable of trapping all viruses present in wastewater samples.

Evaluation of removal of noroviruses during wastewater treatment, using real-time reverse transcription-PCR: different behaviors of genogroups I and II.

Noroviruses, an important cause of gastroenteritis, are excreted by infected individuals and are therefore present in wastewater. We quantified norovirus genogroup I (GI) and GII in wastewater at different locations in France and evaluated removal by a range of treatment types, including basic (waste stabilization pond), current industry standard (activated sludge), and state-of-the-art (submerged membrane bioreactor) treatments. Noroviruses were quantified using real-time reverse transcription-PCR (rRT-PCR). Mengovirus was used as a virus extraction control, and internal controls were used to verify the level of GI and GII rRT-PCR inhibition. A total of 161 (81 influent and 79 effluent) samples were examined; GI and GII were detected in 43 and 88% of the influent samples, respectively, and in 24 and 14% of the effluent samples, respectively. Physicians in France report far more cases of GII than GI during outbreaks; thus, the frequent presence of GI was unexpected. The GI influent concentrations were more variable, the peak GI influent concentrations were higher than the peak GII influent concentrations at all four sites (up to 1 x 10(9) and 6 x 10(7) genome copies/liter, respectively), and the average positive influent concentrations of GI were higher than the average positive influent concentrations of GII. The maximum effluent breakthrough concentrations were 6 x 10(6) and 3 x 10(6) genome copies/liter for GI and GII, respectively, indicating that the four treatment systems studied decreased the norovirus contamination load in receiving waters.