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An examination of shallow GAC filter caps to promote biological filtration without requiring costly full filter bed media replacements.

AimsIn many low-income countries, fasting glucose is the primary measure of glycaemic control used for treatment titration, as HbA1c is often unavailable or unaffordable. Many patients in these countries walk long distances to the clinic, but the impact of walking on fasting glucose in type 2 diabetes is unknown. We aimed to determine whether this prolonged walking affects the reliability of fasting plasma glucose as a measure of glycaemic control.MethodsIn a randomised crossover trial, the change in glucose from baseline in the fasting state was compared between walking on a treadmill at a predetermined speed of 4.5 km/hour for 1 hour and not walking (resting) in people with type 2 diabetes. The pre-specified primary outcome was glucose at 1 and 2 hours.Results45 participants were enrolled and all completed both visits. 21/45 (46.7%) were female, and the median age was 51. Glucose during and after walking was similar to glucose while at rest; glucose difference (walking minus rest) was -0.15 (95% CI: -0.55, 0.26) and -0.10 (95% CI: - 0.50, 0.31) mmol/L at 1 and 2 hours respectively, p>0.4 for both).ConclusionsFasting plasma glucose is not meaningfully affected by prolonged walking in participants with type 2 diabetes; therefore, the reliability of fasting glucose for monitoring glycaemic burden is unlikely to be altered in patients who walk to the clinic.Research in contextWhat is already known about this subject?Fasting glucose is widely used to assess glycaemic control in people living with diabetes in low income countries, as HbA1c and home glucose monitoring are unaffordable. In these settings people living with diabetes will often walk long distances to receive healthcare.Little is known on the impact of walking on fasting glucose in people living with diabetes.What is the key question?Is fasting plasma glucose measure affected by a single bout of exercise such as walking in individuals with type 2 diabetes (T2D)?What are the new findings?There was no significant change in fasting glucose at the end of the walking exercise.There was no meaningful change in fasting glucose observed at any point up to 3 hours after commencing exercise.How might this impact on clinical practice in the foreseeable future?Fasting plasma glucose is not meaningfully affected by prolonged walking in participants with type 2 diabetes; therefore, the reliability of fasting glucose for monitoring glycaemic burden is unlikely to be altered in patients who walk to the clinic.

Background: The role of nutrient timing in energy intake amongst people with dysglycaemia is understudied but could be a simple method to help regulate appetite. This study analysed within-person associations of sugar intake at breakfast and subsequent energy intake. Methods: We used 4-day diet diary data from 147 participants (47 % men) encompassing 547 days of diet recording in the Sedentary Time and Metabolic Health in People with Type 2 diabetes project (STAMP-2). Linear two-level models were used to investigate within- (day-level) and between-person (participant-level) variation in total and post-breakfast energy intake according to skipping breakfast, low- (> 0-14.2 g) or high- (> 14.2 g) sugar intake at breakfast, adjusting for potential confounding or mediation. Results: Post-breakfast energy intakes were observed to be lower after eating low- and high-sugar breakfasts (compared to skipping), but higher total energy intake was associated with eating a high-sugar breakfast. Compared to breakfast skipping, both low- and high-sugar breakfasts were strongly associated with lower post-breakfast energy intake (-178, 95 % confidence interval [CI] -261, -94 kcal/d; ‑151, 95 % CI -235, -67 kcal/d, respectively). However, compared to skipping breakfast, low-sugar breakfasts were weakly associated with higher total daily energy intake (64, 95 % CI -18, 146 kcal/d), whereas high-sugar breakfasts had a strong association (135, 95 % CI 52, 217 kcal/d). Post-breakfast energy intakes were similar between low- and high-sugar breakfast days (27, 95 % CI -53, 106 kcal/d), whilst total daily energy intake tended to be higher with high- (compared to low-) sugar breakfasts (70, -8, 149 kcal/d). We also observed evidence of energy compensation whereby 86 % of the extra energy consumed in a low-sugar breakfast was compensated for by reductions in post-breakfast energy intakes, compared to only 53 % after a high-sugar breakfast. Conclusion: Overall, high-, but not low-, sugar breakfasts were associated with higher total daily energy intake when compared to breakfast skipping, despite a similar reduction in post-breakfast energy intake. We found evidence of poorer post-breakfast energy intake compensation with high-sugar breakfasts than low-sugar breakfasts. These findings suggest portion size may be important to consider in future breakfast research, with sugar being a proxy of portion size.

Concern exists regarding potential health impacts associated with contaminants of emerging concern (CECs) that adsorb to microplastics (MPs). Previous studies have examined MPs as potential contaminant vectors in marine environments as opposed to freshwaters that represent drinking water sources. This study examined adsorption of two polycyclic aromatic hydrocarbons (PAHs), phenanthrene and fluoranthene, by virgin and weathered polyethylene (PE) in both artificial and natural freshwater matrices. Adsorption kinetics and isotherms conducted in artificial freshwater (AFW) consistently showed higher adsorption onto smaller (200 μm) PE when compared to 1090 μm PE. Adsorption mechanisms were primarily associated with hydrophobic interactions and monolayer chemisorption. As well, environmental factors including dissolved organic matter (DOC), pH, and polymer weathering also impacted adsorption. This work provides new insights regarding the adsorption of organic pollutants to better understand the risk of MPs in drinking water sources.

ContextSalt and water homeostasis is regulated hormonally, so polyuria can result from endocrine disease directly or via secondary effects. These mechanisms are not consistently considered in primary care management of nocturia.ObjectiveTo conduct a systematic review (SR) of nocturia in endocrine disease and reach expert consensus for primary care management.Evidence acquisitionFour databases were searched from January 2000 to April 2020. A total of 4382 titles and abstracts were screened, 36 studies underwent full-text screening, and 14 studies were included in the analysis. Expert and public consensus was achieved using the nominal group technique (NGT).Evidence synthesisTwelve studies focused on mechanisms of nocturia, while two evaluated treatment options; none of the studies took place in a primary care setting. NGT consensus identified key clinical evaluation themes, including the presence of thirst, a medical background of diabetes mellitus or insipidus, thyroid disease, oestrogen status, medications (fluid loss or xerostomia), and general examination including body mass index. Proposed investigations include a bladder diary, renal and thyroid function, calcium, and glycated haemoglobin. Morning urine osmolarity should be examined in the context of polyuria of >2.5 l/24 h persisting despite fluid advice, with urine concentration >600 mOsm/l after fluid restriction excluding diabetes insipidus. Treatment should involve education, including adjustment of lifestyle and medication where possible. Any underlying endocrine disorder should be managed according to local guidance. Referral to endocrinology is needed if there is hyperthyroidism, hyperparathyroidism, or morning urine osmolarity ConclusionsEndocrine disease can result in nocturia via varied salt and water regulation pathways. The aim of management is to identify and treat causative factors, but secondary effects can restrict improvements in nocturia.Patient summaryPeople with altered hormone function can suffer from severe sleep disturbance because of a need to pass urine caused by problems in controlling water and salt levels. An expert panel recommended the best ways to assess and treat these problems on the basis of the rather small amount of up-to-date published research available.

Patients with nocturia are commonly referred to urology clinics, including many for whom a nonurological medical condition is responsible for their symptoms. The PLanning Appropriate Nocturia Evaluation and Treatment (PLANET) study was established to develop practical approaches to equip healthcare practitioners to deal with the diverse causes of nocturia, based on systematic reviews and expert consensus. Initial assessment and therapy need to consider the possibility of one or more medical conditions falling into the “SCREeN” areas of Sleep medicine (insomnia, periodic limb movements of sleep, parasomnias, and obstructive sleep apnoea), Cardiovascular (hypertension and congestive heart failure), Renal (chronic kidney disease), Endocrine (diabetes mellitus, thyroid disease, pregnancy/menopause, and diabetes insipidus), and Neurology. Medical and medication causes of xerostomia should also be considered. Some key indicators for these conditions can be identified in urology clinics, working in partnership with the primary care provider. Therapy of the medical condition in some circumstances lessens the severity of nocturia. However, in many cases there is a conflict between the two, in which case the medical condition generally takes priority on safety grounds. It is important to provide patients with a realistic expectation of therapy and awareness of limitations of current therapeutic options for nocturia.Patient summaryNocturia is the symptom of waking at night to pass urine. Commonly, this problem is referred to urology clinics. However, in some cases, the patient does not have a urological condition but actually a condition from a different speciality of medicine. This article describes how best the urologist and the primary care doctor can work together to assess the situation and make sensible and safe treatment suggestions. Unfortunately, there is sometimes no safe or effective treatment choice for nocturia, and treatment needs to focus instead on supportive management of symptoms.

This study examines the removal of microplastics and other anthropogenic particles (10 μm) from surface water by a full-scale conventional drinking water treatment plant. The treatment process is composed of coagulation with aluminum hydroxide, flocculation, anthracite-sand filtration, and chlorination. Samples were also collected from pilot-scale biological filters consisting of anthracite-sand or granular activated carbon (GAC) media operated with or without pre-ozonation and at a range of different empty-bed contact times (EBCTs). Particles in 10 L water samples collected in duplicate using a fully enclosed sampling apparatus were separated using sieves with 500 μm, 300 μm, 125 μm, and 45 μm openings followed by filtration through 10 μm polycarbonate filters. Particles were counted using stereomicroscopy and characterized using μ-Raman spectroscopy. Full-scale conventional treatment removed 52 % of anthropogenic particles when comparing raw (42 ± 18 particles/L) and finished water (20 ± 8 particles/L). Coagulation, flocculation, and sedimentation accounted for the highest removal (70 %) of any individual unit process. Overall removal was reduced to 52 %, the difference being attributed to airborne particle deposition that occurred while water was detained in a clearwell (exposed to atmosphere via ventilation) that was used to achieve the required contact time for disinfection. The majority of the particles (80 %) were identified as fibers 10-45 μm; microplastics were predominantly composed of polyester while the non-plastic anthropogenic particles were primarily cellulose. None of the pilot filter configurations examined resulted in significantly fewer microplastics when compared to full-scale conventional filtration. This study illustrates that the removal efficiency of conventional treatment may be limited when considering microfibers45 μm in size.

Microfiltration (MF) and ultrafiltration (UF) consistently remove suspended material and pathogens from drinking water; however, membrane fouling inhibits their application by increasing operation and maintenance costs. Coagulation/flocculation is a commonly used pretreatment method for the reduction of membrane fouling; in this review it has been grouped into three typical configuration types: Type 1: coagulation + no/incidental flocculation, Type 2: coagulation + flocculation, and Type 3: conventional coagulation, based on operational conditions. The impact of each configuration on floc properties, membrane fouling, and organics removal has been reviewed in detail. Due to relatively high membrane resistance and low NOM reductions, configuration Type 1 may not be optimal for fouling control and organics removal when compared to Types 2 and 3. Configuration Type 2 led to the lowest cake layer and specific cake layer resistance for both MF and UF, while there is evidence that Type 3 results in the greatest reduction in fouling rate by reducing mass flux towards the membrane surface. As expected, with no coagulant results indicate that UF achieves greater organics removal when compared to MF, but with the addition of coagulant performance is similar for all configuration types. By highlighting the connection between coagulation/flocculation configuration types and membrane performance, the review provides insight for the design and operation of pretreatment for low pressure membrane filtration. In addition, understanding the impact of configuration types on floc properties aids in revealing the fouling mechanisms that dictate membrane performance. Knowledge gaps have been identified for guidance on future research.

Incorporation of a carbon-based nutrient enhancement strategy for drinking water biofiltration is an attractive option, especially for source waters which contain recalcitrant organics. This study compared biofilters that were operated in parallel and individually enhanced with amino acids (including alanine, phenylalanine, and tryptophan), inulin, and sucrose to increase biomass concentration and promote biodegradation of dissolved organic carbon (DOC) in the source water, including disinfection by-product (DBP) precursors. Biomass activity was characterized by measuring adenosine tri-phosphate (ATP), dissolved oxygen (DO) consumption, and through the use of laccase and esterase enzyme assays. Performance was evaluated in terms of headloss, turbidity, pH, DOC, UV254, and DBP formation potential (DBP FP). The introduction of carbon-based nutrients significantly increased biomass activity, where ATP values peaked at 976 ng/g of filter media, 853 ng/g, and 513 ng/g for amino acids, inulin, and sucrose-spiked biofilters, respectively, while a non-spiked control only reached 104 ng/g. DO utilization by the enhanced biofilters was significantly higher than the control, with a strong correlation between ATP and DO uptake observed for all filters (R2 > 0.74). Laccase and esterase enzyme activities of enhanced biofilters were also elevated (p > 0.05), suggesting greater biodegradation potential. Operational parameters such as headloss development and turbidity control were not impaired by carbon supplementation strategies or an increase in biomass concentration and activity. However, the enhancement strategy did not provide improvement in terms of source water carbon removal (DOC and UV254) or DBP FP when treated filters were compared to a control.

Biofiltration has been shown to be effective for disinfection by-product (DBP) precursor control, however few studies have considered its role in the potential formation of DBPs. Biofilm is composed of heterogeneous bacteria as well as extracellular polymeric substances (EPS). The objective of this study was to determine the contribution of biofilm-related materials such as EPS to form nitrogen-containing DBPs upon chloramination, and to determine the influence of cyclical (scheduled on-off) biofilter operation on DBP precursor removal. Biologically active media was sampled from a full-scale biofilter operating under cold-water conditions (3.6 ± 0.5 °C) and extracted using a cation exchange resin into a phosphate buffer solution. Biomass concentrations, as determined using adenosine triphosphate (ATP) measurements, remained stable at 298 ± 55 ng ATP/g media over the trial period. N-nitrosodimethylamine (NDMA) and haloacetonitrile (HAN4) formation potential (FP) tests conducted under uniform formation conditions (UFC) using extracted biofilm yielded 0.80 ± 0.27 ng NDMA/g media and 18.7 ± 3.3 ng dichloroacetonitrile (DCAN)/g media. Further analyses of extracted biofilm using fluorescence spectroscopy and liquid chromatography-organic carbon detection indicated the presence of proteins above 20 kDa and humic-like substances. Extracted proteins (93.5 ± 8.1 μg/g media) correlated well (R = 0.90) with UV 280 measurements, indicating that spectrophotometry may serve as a valuable tool to quantify proteins in extracted biofilms. While substances in biofilms can serve as NDMA and DCAN precursors, the full-scale cyclically-operated biofilter that was examined did not show release of NDMA precursors during start-up following stagnation periods of 6 h or more. These biofilters consistently removed 6.9 ± 4.3 ng/L of NDMA precursors; typical NDMA UFC-FP of biofilter effluent was 8.5 ± 2.6 ng/L.

The objective of this pilot study was to evaluate the impact of cyclical (operated 8–12 h per day) and continuous biofilter operation with respect to biomass development, biological enzyme activity and treated water quality (in terms of organics, nutrients and disinfection by-product (DBP) formation potential). Continuously operated biofilters developed greater densities of biomass, as measured by ATP, when compared to cyclically operated filters; reducing the empty bed contact time (EBCT) increased biomass density under continuous flow conditions. However, once normalized to biomass, it was shown that cyclically operated filters exhibited higher enzyme activity, indicating that this method of operation may improve bacterial function. Reduction of organics was generally similar for both continuous and cyclical filters with the same EBCT, however, cyclical filters demonstrated higher variability during the first 4 h following start-up. Overall, HAA formation potential was better controlled by continuously operated filters, due to poor performance by the cyclical filters upon start-up while THM precursors were removed equally well by all filters. To understand the removal capacity for NDMA precursors through biological filters, both naturally occurring NDMA FP and NDMA FP resulting from spiked anthropogenic precursors was monitored through the filter depth. All the filters removed 90% of the naturally occurring NDMA FP within the first 45 cm; cyclical operation resulted in higher reduction of spiked anthropogenic NDMA precursors (50% higher than continuously operated) demonstrating the advantage of routine shut down on overall microbial activity. Tools to monitor and predict biofilter performance are in high demand. Here we present an “effective activity” term which combines enzyme activity with contact time (EBCT). Effective esterase activity was strongly correlated to DOC reduction as a function of filter operation (cyclical or continuous) and EBCT; effective phosphatase activity was indicative of phosphate removal. The results of this study indicate that routine shut down of the filters as this location improved enzyme activity without compromising control of chlorinated DBPs (THMs and HAAs) or NDMA derived from natural and anthropogenic precursors.

Many water providers monitor adenosine triphosphate (ATP) as an indicator of biological acclimation of their biofilters; however, strong correlations between ATP concentration and filter performance (e.g., organic matter or disinfection by-product precursor removal) are not typically observed. As an alternative, this study evaluated the use of enzyme activity for monitoring biological processes within filters. Recent studies have proposed that enzyme activity may be used as an indicator of biofilter function as it provides a means to quantify biodegradation which may allow for a more accurate measure of degradation potential and to gain a better understanding of biofilter performance. Sampling was completed from full- and pilot-scale biofilters to assess impacts associated with pre-treatments, varying sources waters, as well as pre-treatment and operating conditions. Enzyme activity (carboxylic esterase, phosphatase, s-glucosidase, α-glucosidase, s-xylosidase, chitinase, and cellulase) and ATP were measured from the top 5 cm of biofilter media representative of typical full-scale sampling; water quality parameters included dissolved organic carbon (DOC) and disinfection by-products (DBPs): trihalomethane (THM) formation potential (FP), and haloacetic acid FP (HAA FP). Results confirmed that ATP was not a reliable monitoring tool for DOC and DBP FP reduction in biofilters. A strong relationship was observed between esterase activity and DOC reduction; chitinase activity significantly correlated to THM FP reduction for filters treating three different source waters and HAA FP reduction achieved by filters treating the same source water with a range of pre-treatment and backwash conditions. This study showed that enzyme activity may be appropriate for monitoring biological processes within drinking water filters and may act as a surrogate for the removal of organic compounds.

Plastic pollution is a defining environmental contaminant and is considered to be one of the greatest environmental threats of the Anthropocene, with its presence documented across aquatic and terrestrial ecosystems. The majority of this plastic debris falls into the micro (1 μm–5 mm) or nano (1–1000 nm) size range and comes from primary and secondary sources. Its small size makes it cumbersome to isolate and analyze reproducibly, and its ubiquitous distribution creates numerous challenges when controlling for background contamination across matrices (e.g., sediment, tissue, water, air). Although research on microplastics represents a relatively nascent subfield, burgeoning interest in questions surrounding the fate and effects of these debris items creates a pressing need for harmonized sampling protocols and quality control approaches. For results across laboratories to be reproducible and comparable, it is imperative that guidelines based on vetted protocols be readily available to research groups, many of which are either new to plastics research or, as with any new subfield, have arrived at current approaches through a process of trial-and-error rather than in consultation with the greater scientific community. The goals of this manuscript are to (i) outline the steps necessary to conduct general as well as matrix-specific quality assurance and quality control based on sample type and associated constraints, (ii) briefly review current findings across matrices, and (iii) provide guidance for the design of sampling regimes. Specific attention is paid to the source of microplastic pollution as well as the pathway by which contamination occurs, with details provided regarding each step in the process from generating appropriate questions to sampling design and collection.

Application of real-time fluorescence excitation emission matrices (EEM) as a tool for water quality assessment was investigated. A bench-scale fluorescence system with on-line monitoring capabilities was used to quantify several polycyclic aromatic hydrocarbons (PAHs) and pesticides in surface waters of Ontario, Canada. Parallel factors analysis (PARAFAC), an unsupervised multi-way analysis approach, was compared to a supervised peak-picking approach. Both approaches produced sensitive regression models capable of predicting contaminant concentration with mean absolute errors (MAE) that ranged from 0.032 to 0.293 μg L−1 for lake water, and 0.052 to 0.921 μg L−1 for river water. In addition, results showed accurate detection of contaminant concentrations exceeding 0.25 μg L−1. However, concentration and variability of natural organic matter (NOM) in natural waters presented unique challenges to peak-picking, PARAFAC, and regression analysis, which were mitigated by expert supervision as well as site-specific and timely calibration.

MX precursor removal was compared at pilot-scale in continuously and cyclically operated biofilters with empty bed contact times (EBCTs) of 15 and 30 minutes. Water and filter media samples were collected under ambient water quality conditions and during a spike of 7 mg L−1 humic acid (HA). MX formation potential (FP) removals ranged from 26 to 49% and 45 to 61% under ambient precursor and spiked conditions, respectively, suggesting that biofiltration was capable of removing or altering MX precursors. Removal was very strongly correlated (R = 0.90) with ATP (a measure of biomass density) for all trials. MX FP reduction was significantly higher (p < 0.05) with respect to biomass density when comparing cyclically vs. continuously operated filters for all trials. Although lower average ATP concentrations were observed for the cyclically operated filters, these filters achieved a greater MX FP reduction per unit biomass which implies a higher rate of biological function. EBCT did not impact biofilter performance when considering MX FP reduction with respect to either filter depth or biomass density.

Quantitative microbial risk assessments (QMRA) was conducted for 10 drinking water facilities located in Canada. Monthly risk estimates were based upon a suite of reference pathogens for the raw water, as well as detailed process assessments that considered the variability treatment at individual treatment facilities. The majority of the facilities (9 out of 10) maintained risk levels significantly below the World Health Organization's target of 10−6 DALY per person per year. Cryptosporidium was shown to be the most significant contributor for microbial risk at all locations. Potential treatment specific failure scenarios were evaluated; most treatment facilities were capable of withstanding partial filtration and disinfection failures as a result of the multi-barriers employed.

This study examined the impact of ozone (O3) and hydrogen peroxide+ozone (H2O2+O3) on organic matter and subsequent DOC and DBP precursor uptake across biofilters. Organic matter fractionation, using liquid chromatography – organic carbon detection (LC-OCD), confirmed that both O3 and H2O2+O3 oxidized high molecular weight fractions (biopolymers and humics) creating smaller, more easily biodegraded compounds (low molecular weight acids). O3 decreased trihalomethane (THM) and haloacetic acid (HAA) formation potential (FP) by 23% and 15% respectively; H2O2+O3 resulted in an increase of 52% and 41%. Biological activated carbon (BAC) removed 6% of DOC; removals increased to 15% and 23% when preceded by O3 or H2O2+O3, respectively. BAC without pre-oxidation reduced THM FP by 12%, compared to 38% and 14% removal with O3 and H2O2+O3, respectively. HAA FP decreased by 36% for O3+BAC and 20% for H2O2+O3+BAC; better performance by O3 was likely due to increased HAA precursor formation by the AOP. BAC was found to perform better than anthracite-based biofilters for all parameters. This study highlights the impact of pre-oxidation on organic composition, the benefits of biofiltration when used in combination with pre-oxidants such as ozone, and the importance of pilot-testing to assess alternative treatment processes.

The objectives of this pilot-scale study were to evaluate biological acclimation of virgin granular activated carbon (GAC), quantify the impact of nutrient (phosphorus and nitrogen) enhancement and to compare the performance of parallel biologically active carbon (BAC) filters operated continuously or cyclically (12 h/day), with respect to removal of dissolved organic carbon (DOC) and disinfection by-product (DBP) precursors. Virgin GAC media outperformed biologically active carbon for an initial 4-month period in terms of DOC reduction (30%), as expected based on the superior performance associated with adsorption compared to biodegradation. Once the adsorptive capacity was exhausted and the media was biologically acclimated, the performance of the new GAC was statistically similar in terms of organic carbon and disinfection by-product precursor removal to a filter containing media harvested from a filter operating biologically for 12 years. Phosphorus addition to the filter influent (0.3 mg PO4-P/L; C:N:P = 400:1:30) had a small impact on DOC (3 ± 2%) and THM formation potential (5 ± 3%) reduction when compared to biofiltration without nutrient enhancement. Ammonia nitrogen added to the filter influent (0.8 mg NH4-N/L; C:N:P = 200:40:1) was completely consumed through the biofilter; however, no impact on measured performance parameters was observed. Cyclical operation of full-scale biofilters resulted in a modest, but significant improvement in DOC removal (3 ± 2%) when compared to continuously operated pilot filters. Genotyping of both cyclically and continuously operated biofilters (with varying GAC ages) showed similar community composition; however, differences in the phylogenetic diversity of the samples were evident.

The use of fluorescence data coupled with neural networks for improved predictability of drinking water disinfection by-products (DBPs) was investigated. Novel application of autoencoders to process high-dimensional fluorescence data was related to common dimensionality reduction techniques of parallel factors analysis (PARAFAC) and principal component analysis (PCA). The proposed method was assessed based on component interpretability as well as for prediction of organic matter reactivity to formation of DBPs. Optimal prediction accuracies on a validation dataset were observed with an autoencoder-neural network approach or by utilizing the full spectrum without pre-processing. Latent representation by an autoencoder appeared to mitigate overfitting when compared to other methods. Although DBP prediction error was minimized by other pre-processing techniques, PARAFAC yielded interpretable components which resemble fluorescence expected from individual organic fluorophores. Through analysis of the network weights, fluorescence regions associated with DBP formation can be identified, representing a potential method to distinguish reactivity between fluorophore groupings. However, distinct results due to the applied dimensionality reduction approaches were observed, dictating a need for considering the role of data pre-processing in the interpretability of the results. In comparison to common organic measures currently used for DBP formation prediction, fluorescence was shown to improve prediction accuracies, with improvements to DBP prediction best realized when appropriate pre-processing and regression techniques were applied. The results of this study show promise for the potential application of neural networks to best utilize fluorescence EEM data for prediction of organic matter reactivity.

To date, no standardized methods have been proposed for conducting microplastic analyses in treated drinking waters, resulting in challenges associated with direct comparisons among studies. This study compares known methods for collecting and extracting microplastics from drinking waters: an in-laboratory (in-lab) filtration method and an in-line filtration method (i.e., water filtered on-site without an intermediate storage and/or transportation step). In-lab methods have been the predominant method for sample collection in drinking water matrices, and in-line methods are emerging due to the potential to sample large volumes of water on site and minimize contamination from airborne particles, but the two methods have yet to be directly compared using real samples. In response, this study evaluates both methods in terms of recovering spiked reference microplastics, collecting microplastics from tap water samples using the same water volume, and quantifying the removal of microplastics through a full-scale ultrafiltration system. In-line filtration was shown to have higher recoveries for all the reference microplastics examined (+37 % for PVC fragments, +23 % for PET fragments, +22 % for nylon fibers and +7 % for PET fibers) and a greater potential to reduce microplastic contamination. It also resulted in lower standard deviations for total microplastic counts in the tap water and UF influent and effluent samples. The filtration capacity of the proposed in-line filtration method could exceed 350 L of treated water, but this is highly dependent on the water quality. This study therefore supports the use of in-line filtration methods towards the standardization of microplastic collection procedures in drinking water.

A major drawback to ultrafiltration membrane operation for drinking water treatment is fouling, which results in lower water production and increased maintenance costs. The impact of different fouling mitigation strategies including, sparging conditions (duration and air flow rate) as well as phased in-line coagulation were investigated at pilot-scale. Unexpectedly, sparging during permeation and backwash resulted in a significantly higher rate of increase in irreversible resistance compared to Sparging only during backwash. Lower irreversible fouling observed without sparging during permeation was attributed to the formation of a protective layer on the membrane in the absence of sparging. Sparging at reduced air flow rates and intermittently, during the permeation cycle did not improve the irreversible resistance rate when compared to sparging only during backwash. The application of phased in-line coagulation to pre-coat membranes was also investigated. Coagulating for only the first half of the permeation cycle (phased coagulation) did not negatively impact membrane performance in terms of irreversible resistance and organics removal. Phased coagulation, which would lead to reduced coagulant and sludge disposal costs, appears to be a promising fouling control strategy.

Surface waters may contain varying levels of wastewater effluent associated with de facto reuse, which may influence their toxicological properties both prior to and following treatment. This study examined the genotoxic response of three surface waters containing a range of wastewater effluent (5%, 10%, and 25% by volume). The SOS Chromotest™ was used to assay the genotoxicity of both chlorinated and unchlorinated mixtures. Chlorinated mixtures were also analyzed for trihalomethanes (THMs), haloacetonitriles (HANs), and halonitromethanes (HNMs); their concentrations were used to calculate a relative toxicity index for each sample, based on published potencies in the comet assay and subsequently referred to as predicted genotoxicity. Wastewater effluents were observed to be reactive in the genotoxicity assay, whereas raw and chlorinated surface waters were not. Upon chlorination, surface waters containing 5% or 10% wastewater did not elicit a response and only modest effects were observed for higher wastewater ratios (25%). The measured SOS responses correlated well with predicted genotoxicity (R = 0.92) and THM concentrations (R = 0.92). This is important since THMs themselves are non-reactive in either the SOS or comet genotoxic assays, but their formation may serve as surrogates for non-regulated DBPs which drive toxic effects.

The presence of municipal wastewater at the intake of a major drinking water treatment facility located on Lake Ontario was examined using fluorescence data collected during a period of continuous monitoring. In addition, controlled mixing of lake water and wastewater sampled from a local treatment facility were conducted using a bench-scale fluorescence system to quantify observed changes in natural organic matter. Multivariate linear regression was applied to components derived from parallel factors analysis. The resulting mean absolute error for predicted wastewater level was 0.22% (V/V, wastewater/lake water), indicating that wastewater detection at below 1.0% (V/V) was possible. Analyses of sucralose, a wastewater indicator, were conducted for treated wastewater as well as surface water collected at two intake locations on Lake Ontario. Results suggested minimal wastewater contribution at the drinking water intake. A wastewater detection model using a moving baseline was developed and applied to continuous fluorescence data collected at one of the drinking water intakes, which agreed well with sucralose results. Furthermore, the simulated addition of 1.0% (V/V) of wastewater/wastewater was detectable in 89% of samples analyzed, demonstrating the utility of fluorescence-based wastewater monitoring.

Fluorescence spectroscopy as a means to detect low levels of treated wastewater impact on two source waters was investigated using effluents from five wastewater facilities. To identify how best to interpret the fluorescence excitation-emission matrices (EEMs) for detecting the presence of wastewater, several feature selection and classification methods were compared. An expert supervised regional integration approach was used based on previously identified features which distinguish biologically processed organic matter including protein-like fluorescence and the ratio of protein to humic-like fluorescence. Use of nicotinamide adenine dinucleotide-like (NADH) fluorescence was found to result in higher linear correlations for low levels of wastewater presence. Parallel factors analysis (PARAFAC) was also applied to contrast an unsupervised multiway approach to identify underlying fluorescing components. A humic-like component attributed to reduced semiquinone-like structures was found to best correlate with wastewater presence. These fluorescent features were used to classify, by volume, low (0.1-0.5%), medium (1-2%), and high (5-15%) levels by applying support vector machines (SVMs) and logistic regression. The ability of SVMs to utilize high-dimensional input data without prior feature selection was demonstrated through their performance when considering full unprocessed EEMs (66.7% accuracy). The observed high classification accuracies are encouraging when considering implementation of fluorescence spectroscopy as a water quality monitoring tool. Furthermore, the use of SVMs for classification of fluorescence data presents itself as a promising novel approach by directly utilizing the high-dimensional EEMs.

Certain unregulated disinfection byproducts (DBPs) are more of a health concern than regulated DBPs. Brominated species are typically more cytotoxic and genotoxic than their chlorinated analogs. The impact of granular activated carbon (GAC) on controlling the formation of regulated and selected unregulated DBPs following chlorine disinfection was evaluated. The predicted cyto- and genotoxicity of DBPs was calculated using published potencies based on the comet assay for Chinese hamster ovary cells (assesses the level of DNA strand breaks). Additionally, genotoxicity was measured using the SOS-Chromotest (detects DNA-damaging agents). The class sum concentrations of trihalomethanes, haloacetic acids, and unregulated DBPs, and the SOS genotoxicity followed the breakthrough of dissolved organic carbon (DOC), however the formation of brominated species did not. The bromide/DOC ratio was higher than the influent through much of the breakthrough curve (GAC does not remove bromide), which resulted in elevated brominated DBP concentrations in the effluent. Based on the potency of the haloacetonitriles and halonitromethanes, these nitrogen-containing DBPs were the driving agents of the predicted genotoxicity. GAC treatment of drinking or reclaimed waters with appreciable levels of bromide and dissolved organic nitrogen may not control the formation of unregulated DBPs with higher genotoxicity potencies. Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Ministério da Educação//CAPES/Brasil Universidad de Costa Rica//UCR/Costa Rica University of Toronto//UofT/Canadá UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro en Investigación en Contaminación Ambiental (CICA)

N-Nitrosodimethylamine (NDMA) is a disinfection by-product (DBP) with many known precursors such as amine-containing pharmaceuticals that can enter the environment via treated wastewater. Reverse osmosis and tight nanofiltration membranes (MW cutoff200 Da) are treatment technologies that demonstrate high removal of many compounds, but at relatively high energy costs. Looser membranes (200 Da) may provide sufficient removal of a wide range of contaminants with lower energy costs. This study examined the rejection of pharmaceuticals that are known NDMA precursors (∼300 Da) using nanofiltration (MW cutoff ∼350 Da). MQ water was compared to two raw water sources, and results illustrated that NDMA precursors (as estimated by formation potential testing) were effectively rejected in all water matrices (84%). Mixtures of pharmaceuticals vs. single-spiked compounds were found to have no impact on rejection from the membranes used. The use of MQ water vs. surface waters illustrated that natural organic matter, colloids, and inorganic ions present did not significantly impact the rejection of the amine-containing pharmaceuticals. This study illustrates that NDMA formation potential testing can be effectively used for assessing NDMA precursor rejection from more complex samples with multiple and/or unknown NDMA precursors present, such as wastewater matrices.

“Effective Enzyme Activity”, or simply “Effective Activity”, is proposed as a biofiltration monitoring tool which combines enzyme activity with empty bed contact time (EBCT) to quantify biodegradation potential. The primary objective of this study was to evaluate the applicability of the Effective Activity concept for predicting water quality in biofiltration systems. This pilot-scale study evaluated eight different biofilter configurations in order to quantify impacts associated with filter media (anthracite/sand or granular activated carbon), pre-treatment (settled water with or without ozonation) and operating conditions (15- and 30-min EBCT, and backwash with or without chlorine). Microbial characterization included biomass concentration, as measured by adenosine triphosphate (ATP), in addition to esterase and phosphatase activity. Water quality parameters included dissolved organic carbon (DOC), trihalomethane (THM) formation potential (FP), haloacetic acid (HAA) FP, haloacetonitrile (HAN) FP, iodinated DBP FP (THMs and HAAs) and inorganic nutrients (phosphorus and nitrogen). Results confirmed the benefits to treated water quality associated with the application of an ozone residual of 0.5 mg/L, utilization of GAC filter media, eliminating chlorinated backwash, and extending EBCT. This study demonstrated a good relationship between effective esterase activity and reductions in DOC and THM FP, including those systems which incorporate pre-ozonation. As such, this study showed that Effective Activity may be appropriate for relating biomass characterization to treated water quality and highlights the importance of quantifying biomass activity in addition to quantity.

Previous studies have reported that biofilm extracted from full-scale biofilters can serve as nitrogenous disinfection by-product (N-DBP) precursors. Detached biofilm materials could escape during filter ripening and form N-DBP upon chloramination. This study examined the potential breakthrough of biofilm and N-DBP precursors during filter ripening at two water treatment plants (WTPs). The presence of biofilm material in aqueous samples was estimated by total adenosine triphosphate (tATP) levels; N-DBP formation potential (FP) tests were conducted under uniform formation conditions to quantify N-nitrosodimethylamine (NDMA) and haloacetonitrile (HAN4) precursors. While tATP peaks in filter effluent were observed post backwash at both WTPs, temporary increases of effluent NDMA FP were only observed during filter ripening where particle-associated NDMA precursors served as the dominant contributor. Overall, biofilters examined in this study demonstrated a consistent removal of NDMA FP regardless of the filter ripening process.

Objectives Regular physical exercise may preserve β cell function in newly diagnosed adults with type 1 diabetes (T1D). However, clinical trials to test this theory require the recruitment and retention of adults with new-onset T1D, which can be challenging. We sought to determine the overall experiences of newly diagnosed adults with T1D in an exercise study, to understand issues that influence the retention of trial participants in such studies. Design Qualitative methodology using individual face-to-face (n=6) and telephone interviews (n=14). Interview transcripts were thematically analysed using the framework method. Setting The study took place at five participating UK hospitals. Participants Twenty participants, aged 19–55 years, in the Exercise for Type 1 Diabetes study were interviewed to explore their study experiences and identify motivators and deterrents towards the study. Participants in control and intervention arms were interviewed, as were people with T1D who had completed (n=16) and withdrawn (n=4). Results Participants revealed barriers and facilitators to retention; the majority were generalisable to clinical trials of people with newly diagnosed T1D. Coming to terms with a diagnosis of T1D, lack of time, work pressures, level of health professional support, volume, clarity and consistency of information and feedback and a desire for knowledge about their condition were all cited as influencing factors to trial retention. Conclusions To our knowledge, this is the first qualitative study to examine the experience of being involved in an exercise trial by people with T1D. Findings suggest appointments could be shorter, available outside of working hours and planned longer in advance; study information should be clear, consistent and in electronic and paper formats; questionnaires need minimising; healthcare support and feedback needs providing regularly; thought is required around how to support non-exercising arm participants. These considerations may improve participant retention rates in new-onset T1D studies.