Selection and evaluation of water pretreatment technologies for managed aquifer recharge (MAR) with reclaimed water.

Managed aquifer recharge with reclaimed water is a promising strategy for indirect potable reuse. However, residual contaminants in the treated wastewater effluent could potentially have adverse effects on human health. Hence, adequate water pretreatment is required.

Application of long amplicon propidium monoazide-PCR to assess the effects of temperature and background microbiota on pathogens in river water.

The decay rates of enteric waterborne pathogens were evaluated following the introduction of Yersinia enterocolitica, Salmonella enterica, Campylobacter jejuni and Arcobacter butzleri into river water at different temperatures (5, 15 and 25°C) for a period of 28 days. To improve the accuracy of the results a molecular viability assay, long amplicon propidium monoazide-polymerase chain reaction (PMA-PCR), was used to quantify the viable cell concentration and results from PCR with and without PMA were compared. As well, the effect of background microbiota was assessed for Y.

Identification of critical contaminants in wastewater effluent for managed aquifer recharge.

Managed aquifer recharge (MAR) using highly treated effluent from municipal wastewater treatment plants has been recognized as a promising strategy for indirect potable water reuse. Treated wastewater effluent can contain a number of residual contaminants that could have adverse effects on human health, and some jurisdictions have regulations in place to govern these. For those that do not, but where reuse may be under consideration, it is of crucial importance to develop a strategy for identifying priority contaminants, which can then be used to understand the water treatment technologies that might be required.

Application of flow cytometry to monitor assimilable organic carbon (AOC) and microbial community changes in water.

Flow cytometry is an efficient monitoring tool for rapid cell counting, and can be applied to research on water quality and treatment. In this study, a method that employs flow cytometry and a natural microbial inoculum to determine assimilable organic carbon (AOC) was adapted for use with challenging surface waters that have a high organic and particle content, and subsequently applied in a long term river water study. AOC method optimization showed that river water bacteria could pass through a 0.

Kinetics of natural organic matter (NOM) removal during drinking water biofiltration using different NOM characterization approaches.

To better understand biofiltration, concentration profiles of various natural organic matter (NOM) components throughout a pilot-scale drinking water biofilter were investigated using liquid chromatography - organic carbon detection (LC-OCD) and fluorescence excitation and emission matrices (FEEM). Over a 2 month period, water samples were collected from six ports at different biofilter media depths. Results showed substantial removal of biopolymers (i.

Influence of water quality on nitrifier regrowth in two full-scale drinking water distribution systems.

The potential for regrowth of nitrifying microorganisms was monitored in 2 full-scale chloraminated drinking water distribution systems in Ontario, Canada, over a 9-month period. Quantitative PCR was used to measure amoA genes from ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), and these values were compared with water quality parameters that can influence nitrifier survival and growth, including total chlorine, ammonia, temperature, pH, and organic carbon. Although there were no severe nitrification episodes, AOB and AOA were frequently detected at low concentrations in samples collected from both distribution systems.

Effect of hydraulically reversible and hydraulically irreversible fouling on the removal of MS2 and φX174 bacteriophage by an ultrafiltration membrane.

The effect of membrane fouling on the removal of enteric virus surrogates MS2 and φX174 bacteriophage by an ultrafiltration membrane was assessed under simulated full-scale drinking water treatment operating conditions. Filtration experiments of up to 8 days using either river or lake water ascertained how the membrane fouling layer affected virus removal. Organic carbon fractionation techniques identified potential foulants, including biopolymers, in the feed water and in the permeate.

Identifying host sources, human health risk and indicators of Cryptosporidium and Giardia in a Canadian watershed influenced by urban and rural activities.

Cryptosporidium and Giardia were characterized in a watershed in southern Ontario, Canada, over a 2½ year period. River samples were collected every two weeks, primarily near a municipal drinking water treatment plant intake. Cryptosporidium and Giardia were frequently detected with an overall occurrence rate of 88 and 97%, respectively.

The detection of Yersinia enterocolitica in surface water by quantitative PCR amplification of the ail and yadA genes.

Yersinia enterocolitica has been detected in surface water, and drinking untreated water is a risk factor for infection. PCR-based methods have been used to detect Y. enterocolitica in various sample types, but quantitative studies have not been conducted in water.

Size-dependent PCR inhibitory effect induced by gold nanoparticles.

In this work, the effect of gold nanoparticles (AuNPs) with diameters of around 5, 10 and 20 nm on PCR efficiency is evaluated respectively using a real-time PCR machine. Gold nanoparticles show no obvious effect on PCR at low particle concentration. When the concentration is increased, PCR inhibition is observed.

Development of a direct DNA extraction protocol for real-time PCR detection of Giardia lamblia from surface water.

Giardia lamblia is one of the most recognized waterborne protozoan parasites causing gastrointestinal disease. A simple but effective DNA extraction protocol for real-time PCR detection from surface water samples was developed in this study. Eleven protocols were compared, which consisted of freeze-thaw treatments (liquid N(2) and boiling water) and purification using the Qiagen DNeasy kit, together with different combinations of proteinase K, PVP360, GITC and Chelex 100 incubation.

An evaluation of methods for the isolation of Yersinia enterocolitica from surface waters in the Grand River watershed.

Yersinia enterocolitica is a foodborne pathogen, but the importance of water as a route of exposure for human infection is not well known. Y. enterocolitica isolation methods were developed primarily for food and clinical samples, and may not be effective for use with environmental samples.

Molecular biological detection of anaerobic gut fungi (Neocallimastigales) from landfill sites.

Oligonucleotide primers were designed for the 18S rRNA genes of members of the Neocallimastigales and used in a nested PCR protocol to amplify 787-bp fragments of DNA from landfill site samples. The specificities of the primers were confirmed by phylogenetic analysis of the environmental clone sequences, and this method can therefore now be used to investigate the ecology of the obligately anaerobic fungi. To our knowledge, this is the first demonstration of the occurrence of members of the Neocallimastigales outside the mammalian gut, and their distribution across the landfill samples examined here suggests that they are actively involved in cellulose degradation.