bluuebunny/crossref_metadata_2025 huggingface dataset:
Arsenic Mitigation for Water Supply in Bangladesh: Appropriate Technological and Policy Perspectives
Authors: Hoque Bilqis A. , Yamaura Sombo , Sakai Akira , Khanam Sufia , Karim Mahbooba , Hoque Yamen , Hossain Sanowar , Islam Shoriful , Hossain Obaid
Published: May 2018

Drinking of arsenic-contaminated water and the associated health impacts have been reported in developing and developed countries. Bangladesh is faced with the worst arsenic contamination of groundwater in the world, with an estimated 35 to 77 million people at risk of exposure to drinking arsenic-contaminated tubewell water. Lack of appropriate technologies has complicated and inhibited mitigation initiatives. This paper discusses the data obtained during efforts made to develop technologies for safe water supply by the Government of Bangladesh and its national and international partners. It is expected that the information will contribute towards development of appropriate technologies for water supply for millions of people in Bangladesh and other countries.

About 95% of Bangladesh's rural population drinks tubewell water. Both arsenic removal and alternative technologies were widely promoted for water supply in these areas. The government and its national and international development partners developed various arsenic mitigation technologies for water supply, but most of the arsenic removal technologies were promoted without sound testing and showed poor, questionable and/or confusing performance in real situations. Also, use of most of the arsenic removal technologies was discontinued after a few to several months of installation. Concerns about the microbiological contamination of safe feed water during treatment were noted in arsenic removal options, in addition to high costs, efficiency, social and/or other problems. The 2004 National Policy for Arsenic Mitigation and its Implementation Plan stated a need for access to safe drinking water for all through alternative water technologies while arsenic removal technologies are developed and promoted after specified verification.

The national policy specified and widely promoted alternative options such as improved dugwells, safe tubewells, pond sand filters, rainwater harvester and piped water systems from arsenic-safe water sources. A few of the promoted alternative options showed poor functional and social performance, in addition to supplying microbiologically contaminated water. Arsenic-safe shallow tubewells, deep tubewells and piped water systems may be regarded as appropriate technologies under the existing conditions when the performance of the arsenic removal and alternative water technologies were compared. There are constraints in promoting those three water technologies in various hydrogeological conditions throughout the county. A wide range of appropriate technologies needs to be developed and promoted, and the issue of how to deal with the existing millions of arsenic-contaminated tubewells also needs to be considered. Research and development of sound sciencebased appropriate technologies are urgently recommended for effective realization of the Millennium Development Goal for safe water.
Cumulative Effects of Multiple Contaminants on Caged Fish
Authors: Klaverkamp Jack F. , Palace Vince P. , Baron Christopher L. , Evans Robert E. , Wautier Kerry G.
Published: May 2018

Pearl dace (Semotilus margarita) were held in cages and exposed to mine effluents, municipal wastewater effluents, a combination of the two, or to the combination in addition to runoff from a garbage disposal facility. Fish exposed to mining effluents only had the lowest mean lengths and weights but highest concentrations of As, Ni and Hg and lowest Zn in their viscera. Fish exposed to municipal wastewater effluents only had the highest concentrations of Cd and metallothionein in their viscera. Histopathological analyses of gill and liver tissues revealed a higher incidence of lesions in fish exposed to municipal wastewater effluents. These fish also had the highest LSIs, condition factors and mean vitellogenin concentrations in plasma from males. Fish exposed near the garbage disposal site had the highest concentrations of Pb and Se in their viscera.
Accumulation of Marine Debris on an Intertidal Beach in an Urban Park (Halifax Harbour, Nova Scotia)
Authors: Walker Tony R. , Grant Jon , Archambault Marie-Claude
Published: May 2018

This study evaluated monthly accumulation rates and types of marine debris washed ashore at a recreational beach in Point Pleasant Park, Halifax Harbour, between April and September 2005. Black Rock Beach is 70 m long and a total of 2129 marine debris items were collected and sorted, representing a mean accumulation rate of 355 (±68 SE) items month-1. The total weight of debris items was only 10.8 kg (mean 2 kg ±0.4 SE), however eighty-six percent of this debris was plastic material. The types of litter found included: tampon applicators, condoms (i.e., sewage-related debris [SRD]); plastic fast food packaging, confectionary wrappers, Styrofoam fragments, plastic bottles and caps, items of clothing, soft drink cans, cigarettes and cigarette holders (i.e., recreational or land-based debris); packing bands, nylon rope and nets (i.e., shipping- or fishing-related debris). These items were generated by recreational use of the park (52%), sewage disposal (14%) and from shipping and fishing activities (7%). It is suggested that a significant reduction in marine debris at recreational beaches may arise by improving public awareness of the environmental and aesthetic impacts of marine litter and future improvements to the municipal sewage disposal system.
Effectiveness of Vegetative Filter Strips in Removal of Sediments from Overland Flow
Authors: Gharabaghi Bahram , Rudra Ramesh P. , Goel Pradeep K.
Published: May 2018

Many forms of natural heritage manifested as streams, rivers, ponds, lakes and wetlands play an integral role in maintaining natural beauty, health and a high quality of life. Agricultural intensification in southern Ontario has contributed to elevated sediments, nutrient and bacteria levels in water bodies. Vegetative filter strips (VFS) are control measures that can partially remove sediments and pollutants adhered to sediments from overland runoff before entering water bodies. The objective of this study was to determine the effect of vegetation type, width of the filter strip, runoff flow rate and inflow sediment characteristics on effectiveness of the VFS in removing pollutants from runoff. The results show that sediment removal efficiency increased from 50 to 98% as the width of the filter increased from 2.5 to 20 m. In addition to the width of the filter strip, grass type and flow rate were also significant factors. This study indicates that the first five (5) metres of a filter strip are critical and effective in removal of suspended sediments. More than 95% of the aggregates larger than 40 µm in diameter were trapped within the first five metres of the filter strip.
Treatment of Woodwaste Leachate in Surface Flow Mesocosm Wetlands
Authors: Tao Wendong , Hall Ken J. , Duff Sheldon J.B.
Published: May 2018

Woodwaste leachate is usually acidic, of high oxygen demand, and toxic. To prevent potential adverse impacts of the raw leachate on heterotrophic bacteria and aquatic plants, woodwaste leachate was diluted before discharge to constructed wetlands. This study compared treatment performance among four vegetated surface flow mesocosm wetlands fed with different dilutions of woodwaste leachate over a period of 12 weeks. During another period of 13 weeks, the effluent of a vegetated wetland fed with the raw leachate was further treated in a vegetated wetland and an open wetland. The highest reduction rates for chemical oxygen demand as well as tannin and lignin were achieved in the wetland fed with the raw leachate. The most diluted (6x) woodwaste leachate yielded the lowest reduction rates and highest reduction efficiencies. Up to 47 mg L-1 volatile fatty acids in influent were depleted through wetlands with a hydraulic retention time of 13 d. Vegetation made insignificant performance differences for treatment of woodwaste leachate. Chemical oxygen demand as well as tannin and lignin were further removed through the wetlands in series, though at lower reduction rates. Wetland performance for treatment of woodwaste leachate was likely regulated by dissolved oxygen concentration and availability of bacterial substrates.
Adsorption Studies with Arsenic onto Ferric Hydroxide Gel in a Non-oxidizing Environment: the Effect of Co-occurring Solutes and Speciation
Authors: Nayak Bishwajit , Hossain Md. Amir , Sengupta Mrinal Kumar , Ahamed Saad , Das Bhaskar , Pal Arup , Mukherjee Amitava
Published: May 2018

Groundwater arsenic contamination has emerged as a major health threat to millions of people around the world. Studying the sorption process of As(III) and As(V) onto ferric hydroxide gel is important to understand the mobilization of arsenic under nonoxidizing conditions. Most of the previous adsorption studies were limited to single element or multi-element equilibrium in synthetic water. To investigate the effect of matrix and speciation in real groundwater systems, adsorption tests with added As(III) and As(V) separately and in mixture were conducted in both double-distilled deionized water (DDDW) and As-safe (<3 µg L-1) tubewell water. In DDDW, the As(III)/As(V) ratio in the mixture strongly influenced the sorption behaviour by shifting the adsorption edge and also the efficiency. For As(III) and As(V) mixture in 1:1 proportions in tubewell water, the adsorption of both the species decreased up to pH 8; in the alkaline ranges the adsorption extent was marginally increased in comparison to that in DDDW. When As(III):As(V) was added in 3:1 proportions in tubewell water, the adsorption of both was enhanced in alkaline ranges compared to that in DDDW. When As(V) was predominant [As(V):As(III) = 3:1] in tubewell water, no significant changes were observed for As(V), though adsorption of As(III) was notably retarded. The statistical analysis of the results indicates the concentration ratio of As species in the system has a definite impact on adsorption behaviour onto ferric hydroxide gel.
Pharmaceuticals and Endocrine Disruptors in Wastewater Treatment Effluents and in the Water Supply System of Calgary, Alberta, Canada
Authors: Chen Mei , Ohman Klas , Metcalfe Chris , Ikonomou Michael G. , Amatya Prasanna L. , Wilson Jeffrey
Published: May 2018

Due to a growing interest in the occurrence of pharmaceutically active compounds (PhACs) and endocrine disrupting compounds (EDCs) in the aquatic environment and their potential impacts on humans and the environment, a collaborative study was conducted on these emerging contaminants in the effluents from the wastewater treatment plants (WWTPs) and in the drinking water supply system of Calgary, Alberta. A number of PhACs and EDCs were detected in the WWTP effluents, at concentrations ranging from ng/L to low µ-g/L. Although these compounds were generally removed from WWTP effluents during wastewater treatment, some compounds, such as carbamazepine were more persistent. Some target PhACs and EDCs were detected at low ng/L levels in the surface and potable water in this study. Currently, there is no evidence that trace amounts of PhACs and EDCs in Calgary's waterways can have a health impact on humans, but they may pose adverse chronic effects on aquatic life.
Photocatalytic Disinfection of Bacteria by Sodium Light with Smectite Catalysts
Authors: Kuo Shu-Lung , Liao Chiu-Jung
Published: May 2018

In this study, modifications of Wyoming smectite clay minerals are conducted using four types of metallic cations that cover the surface with Ag+, Zn2+, Ti4+ and Ag+/Zn2+ to form smectite catalysts and destroy bacteria. When the smectite catalysts are illuminated with a sodium lamp, they reduce the number of viable bacteria in surface water and achieve a disinfecting effect. On the whole, smectite-Ti catalysts have the best disinfection efficiency, followed by coupled smectite-Ag/Zn catalysts, smectite-Ag catalysts and smectite-Zn catalysts. The higher quantity of catalysts there is, the easier it is for the shielding effect to take place. This causes a lower intensity of sodium light to react with the bacteria. When smectite-Zn catalysts are in the catalytic process, they produce intermediates that can compete for reaction sites with the OH free radicals. This can reduce the production of electrons and holes, and hence the reaction rate of objects on the surface of smectite-Zn catalysts. In smectite-Ag/Zn catalysts, coupled catalysts combine two types of semiconductor catalysts that have different energy gaps and energy band sites. These can separate electrons and holes more efficiently, increase the lifetime of electron carriers, and enhance disinfection efficiency.

This study utilizes factor analysis of multivariate analysis to discuss the correlations between different catalysts, e.g., the four types of smectite catalysts and catalysts with different weight percentages, respectively. The results show two findings: (1) there is only one main factor influencing the disinfection efficiency of the four types of smectite catalysts—the photocatalytic competitiveness factor; and (2) only one main factor affects the disinfection efficiency of the four types of catalysts with different weight percentages—the concentration shielding effect factor.
Assessing the Disinfecting Power of Chlorite in Drinking Water
Authors: Bichai Françoise , Barbeau Benoit
Published: May 2018

The goal of this study was to review and confirm experimentally chlorite effectiveness as a drinking water disinfectant. The steps in the experiment were a series of laboratory assays performed on three types of microorganisms, Bacillus subtilis spores, MS2 coliphages, as well as heterotrophic (HPC) bacteria, to verify chlorite action in water. The tests showed that chlorites have no disinfectant effect on B. subtilis spores (CT > 106 mg min/L), that they slightly decrease HPC bacterial regrowth and, finally, that a dose of 1 and 10 mg ClO2-/L can inactivate almost 2 log and 4.5 log of MS2 phages, respectively, after 9 days of contact time. It would therefore appear that chlorites are not a good primary disinfectant, but do exhibit a bacteriostatic effect.
Variations saisonnières et mobilité potentielle du phosphore sédimentaire de la retenue de barrage Al Massira (Maroc)
Authors: Kemmou Souad , Dafir Jamal-Eddine , Wartiti Mohamed , Taoufik Mohamed
Published: May 2018

Les différentes fractions du phosphore du sédiment de la retenue de barrage Al Massira sont identifiées par l'extraction séquentielle et les échanges à l'interface eau-sédiment sont déterminés par les tests de fixation-relargage. Le phosphore sédimentaire est essentiellement sous formes inorganiques (o-P + Fe(OOH)-P + CaCO3-P=77% du P-Tot) avec la prédominance de la fraction CaCO3-P. Les formes organiques (ASOP + ROP) représentent seulement 23% du P-Tot. Les tests de fixationrelargage ont montré que les formes minérales du phosphore sont les plus impliquées dans les échanges à l'interface eausédiment, en particulier la fraction liée au fer [Fe(OOH)-P]. Les variations saisonnières significatives de Fe(OOH)-P et de CaCO3-P (p< 0,01) au cours d'un cycle annuel expliquent les tendances de stockage et de mobilisation du phosphore par chacune d'entre elles. Ces deux fractions peuvent stocker ou libérer chacune prés de 17% du P-Tot, alors que la mobilité du phosphore mesurée est de 23% du P-Tot. Ce décalage apparent entre la mobilité considérée par fraction et la mobilité totale peut être expliqué par la mobilité interne entre les différentes fractions dans le sédiment. En effet, selon les conditions environnementales (pH, potentiel rédox), le phosphore libéré par une fraction sera en partie récupéré par l'autre.
A Tribute to Richard A. Vollenweider (1922-2007)
Authors: Vallentyne J.R.
Published: May 2018

This study evaluates the suitability of using Hyalella azteca as a predictor of the risk that tributyltin (TBT) poses to freshwater invertebrates by comparing the toxicity and bioaccumulation of TBT in H. azteca to five species: Hexagenia limbata, Physella gyrina, Tubifex tubifex, Chironomus riparius and Daphnia magna. Young from each species were added to aquaria containing sediment spiked with TBT concentrations of 0, 28.6, 258 and 1900 ng Sn/g dry weight. Chironomus riparius data could not be quantified reliably due to poor control survival. Bioaccumulation of TBT in the five remaining species was similar at sediment concentrations of 258 ng Sn/g, and the bioaccumulation relationships of P. gyrina and H. azteca were virtually identical. No toxicity was evident in any test species at body concentrations of 1100 to 1800 ng Sn/g. Body concentrations of 4000 to 6000 ng Sn/g were associated with significant (p < 0.05) mortality in H. limbata, P. gyrina, T. tubifex and D. magna, but not in H. azteca. However, bioaccumulation of TBT in H. azteca was comparable and can be used in predicting the effects of environmental TBT concentrations on these four species of freshwater invertebrates.
Composite Water Quality: Evaluation and Management Feedbacks
Authors: Parparov Arkadi , Hambright K. David
Published: May 2018

In this article we both outline and offer an approach to quantitative estimation of aggregated water quality, in the form of the Composite Water Quality Index (CWQI), calculated as a weighted sum of rating values for a set of preselected water quality indices. The weighting procedure uses variable weights that are inversely proportional to the separate rating values. We also suggest a simplified procedure for estimating the sensitivity of several common algorithms that may be used for CWQI calculations. Among the different methods of CWQI calculation, Smith's minimum operator had the highest sensitivity, while an equal weighting procedure based on the arithmetic mean had the lowest sensitivity. We discuss the relationship between the choice of method for a CWQI calculation and the strategy of water resources management, and show that besides its indicative function, the CWQI should serve as a target of, and tool for, water resources management.
Efficiency of the Coagulation-Flocculation Method for the Treatment of Dye Mixtures Containing Disperse and Reactive Dye
Authors: Wong Pei Wen , Teng Tjoon Tow , Norulaini Nik Abdul Rahman Nik
Published: May 2018

The coagulation-flocculation method was used to treat aqueous solutions containing varying ratios of commercial disperse and reactive dyes. The effectiveness of this method was assessed using such coagulants as alum, polyaluminium chloride (PACl) and MgCl2, and an anionic coagulant aid. The jar test method was used to measure the effects of pH and coagulant type and dosage on colour removal and chemical oxygen demand (COD) reduction. The effect of coagulant aid on floc settling time was also measured. The results showed that the coagulant dosage needed to achieve optimum colour removal and COD reduction increased as the percentage of reactive dye in the mixture increased. Alum and PACl performed effectively in a lower pH range (pH 3.8 to 5.2), whereas MgCl2 performed effectively in a higher pH range (pH 10.4 to 10.9). PACl was more effective than MgCl2 and alum, achieving >99% colour removal and 96.3% COD reduction using a smaller quantity of the coagulant. The addition of coagulant aid improved floc settling time. These results show that PACl is more effective than MgCl2 and alum in removing both colour and COD in the treatment of the industrial textile wastewater samples.
Application of a Pair-Breeding Fathead Minnow (Pimephales promelas) Adult Reproduction Bioassay to a Pulp Mill Effluent
Authors: Rickwood Carrie J. , Dubé Monique G.
Published: May 2018

A short-term reproductive bioassay was applied to observe performance of pair-breeding fathead minnow (Pimephales promelas) before and after exposure to treated pulp and paper mill effluent. Reproductive performance was assessed for 21 days under controlled laboratory conditions to obtain baseline data of endpoints including cumulative egg production, number of spawning events, hatching success, and occurrence of deformed larvae. Breeding pairs were then exposed to 50 and 100% concentrations of secondary treated effluent for an additional 21 days. A significant reduction in egg production after exposure to both 100 and 50% pulp mill effluent was observed. This was accompanied by an increased appearance of pathological lesions (eosinophilic material) in male gonads as well as increased gonad size (gonadosomatic index). Reduced hatching success and appearance of larval deformities were also observed after exposure to both 50 and 100% pulp mill effluent. The pattern of responses observed may indicate that the reduced reproductive output was due to exposure to endocrine disrupting compounds within the effluent. By using the short-term fathead minnow bioassay, we were able to identify a response pattern to pulp mill effluent that is indicative of exposure to estrogenic and/or androgenic compounds.
Sorption of Heavy Metals with Sol-Gel Particles Containing Crude Metallothionein Extracts from Scchizosaccharomyces pombe
Authors: Bahrami Shirin , Bassi Amarjeet S. , Yanful Ernest K
Published: May 2018

Crude metallothionein (MT) extracts from Scchizosaccharomyces pombe entrapped in sol-gels were investigated for the removal of heavy metals such as cadmium and zinc. The sol-gel provided a robust immobilization matrix for the protein extract. Adsorption and desorption isotherms were developed for both cadmium and zinc. Both metals were recovered from the sol-gel by desorption using a 1 M NaCl solution. The adsorption kinetic studies showed that cadmium and zinc adsorption followed the Langmuir isotherm. The distribution factors for cadmium and zinc were found to be 5.43 L/mg and 2.88 L/mg, respectively. Greater than 60% of Zn2+ was also removed using MT sol-gels. The experiments demonstrated that MT has a greater capacity for Cd than polyethyleneimine immobilized in the sol-gels. The adsorption capacity of MT was found to be 588.2 mg of cadmium and 434.8 mg of zinc per gram of immobilized MT, which is significantly higher than with nonbiological chelators such as polyethyleneimine or EDTA.
Polycyclic and Nitro Musks in Canadian Municipal Wastewater: Occurrence and Removal in Wastewater Treatment
Authors: Smyth Shirley Anne , Lishman Lori A. , McBean Edward A. , Kleywegt Sonya , Yang Jian-Jun , Svoboda M. Lewina , Ormonde Sandra , Pileggi Vince , Lee Hing-Biu , Seto Peter
Published: May 2018

The removal and/or partitioning (to sludge) of six polycyclic and five nitro musks through the liquid treatment train of a conventional Canadian secondary activated sludge wastewater treatment plant is characterized. Raw influent, primary effluent, secondary effluent, primary sludge, and waste activated sludge concentrations were correlated to seasonal process temperatures (warm, 22°C; cold, 15°C). Maximum influent concentrations of polycyclic and nitro musks were 7,030 ± 2,120 ng/L for Galaxolide (HHCB) and 158 ± 89 ng/L for musk ketone respectively. Maximum secondary effluent concentrations were 2,000 ± 686 ng/L for HHCB and 51 ± 14 ng/L for musk ketone. Temperature appeared to influence the degree of removal of musks from wastewater during primary clarification (40% median removal at warm temperatures and 9% at cold temperatures) and overall treatment (82% median removal at warm temperatures and 74% at cold temperatures) but not secondary activated sludge treatment (71% median removal at warm temperatures and 70% at cold temperatures). In primary sludge, polycyclic musks were found at concentrations up to 35,000 ng/g for HHCB, and nitro musks were found at concentrations up to 490 ng/g for musk ketone. In waste activated sludge, polycyclic musks were found at concentrations up to 52,000 ng/g (HHCB), and nitro musks were found at concentrations up to 1,100 ng/g (musk ketone). The hydraulic retention time and the suspended solids of the treatment process appeared to influence the degree of partitioning of musks to sludge.
Ion Export from a Small British Columbia Watershed After Forest Harvesting
Authors: Nordin Richard N. , Zhu Zhanxue , Mazumder Asit
Published: May 2018

A small coastal British Columbia lake was monitored before and after approximately 11% of the watershed was logged. There was an increase in the concentrations of most of the ions measured in the lake water after logging. Peak concentrations occurred two to three years after logging and most ions returned to background concentrations in five to eight years. Two methods were used to estimate the increased export of ions resulting from the forest harvesting. The first method used a water chemistry / hydrology watershed model, and the second used the changes in lake concentrations to calculate watershed input. The changes in ion concentrations and export varied with model and chemistry parameter with a change from a 1.3- to 4.2-fold increase for major cations and anions like calcium, magnesium, sodium, and chloride, to a 5- to 35-fold increase in ion export for nitrate and ammonium. The export of nitrogen from the watershed has implications for both water quality and future forest productivity. The measurement of lake ion increase is proposed as a general means of evaluating longer term change or disturbance in a watershed.
Pharmaceuticals in the Yamaska River, Quebec, Canada
Authors: Yargeau Viviane , Lopata Antonina , Metcalfe Chris
Published: May 2018

Pharmaceutically active compounds have been detected in North America and Europe in groundwater, surface water, wastewater, and drinking water. In the province of Quebec in Canada, there has been little data to assess the occurrence of pharmaceutical residues in the aquatic environment. In August of 2005, samples of surface water were collected at 10 sites along the Yamaska River basin in Quebec, which passes through important agricultural areas and receives wastewater from several urban centers with populations ranging up to 44,000 residents. Several acidic drugs (naproxen, ibuprofen, gemfibrozil), neutral drugs (caffeine, carbamazepine, cotinine), and the sulfonamide antibiotic sulfamethoxazole were detected in the majority of the surface water samples. The antidepressant fluoxetine (neutral/basic drug) was not detected in any samples, while acetaminophen (acidic drug) was detected at only two sites, and sulfapyridine (sulfonamide antibiotic) was detected at only one site. Sulfamethoxazole and carbamazepine were present at the highest maximum concentrations of 578 ng/L and 106 ng/L, respectively. The concentrations of most of the target pharmaceutically active compounds observed in surface water samples within the watershed were generally consistent with the number of people in urban centers near the sampling sites when compared with other studies in urban watersheds. However, carbamazepine, naproxen, and sulfamethoxazole were present at surprisingly high concentrations for some of the low density areas. Overall, these results demonstrate that pharmaceuticals are distributed in surface waters within a watershed in Quebec at concentrations similar to levels observed in previous studies done in other parts of North America.
Low-Nitrate-Days (LND), a Potential Indicator of Cyanobacteria Blooms in a Eutrophic Hardwater Reservoir
Authors: Nürnberg Gertrud K.
Published: May 2018

When nitrate was low in a hypereutrophic, hardwater reservoir, cyanobacteria proliferated into blooms. Based on this observation an index was developed that relates an easily measurable variable, the period of Low-Nitrate-Days (LND), to the period when nuisance cyanobacteria (blue-greens) proliferate and “bloom”. The bloom indicator LND (d·yr-1) was defined as the period of time during summer and early fall when nitrate concentration is below a lake-specific threshold. This concept was valuable in Fanshawe Lake, a southern Ontario reservoir of the Thames River in the Lake Erie catchment basin, where traditional bloom indicators are rare. A nitrate threshold of 1 to 2 mg·L-1 is supported by occasional observations of chlorophyll (Chl) concentration, blue-green biomass, visual inspection, and photographic documentation. Fanshawe Lake's water quality (phosphorus, Chl, and Secchi disk transparency) varied from summer to summer and LND ranged from 0 to 175 d·yr-1 with a long-term average of 62 d·yr-1 for 38 years. LND was positively and significantly correlated with average summer total phosphorus concentration (available for 8 years), but not Chl (n = 6) nor transparency (n = 11), possibly because of an invasion by the zebra mussel Dreissena. LND values agreed well with cyanobacteria biomass indicators predicted from other models. Significant relationships with 38 years of flows and the climatic index (winter North Atlantic Oscillation) reveal that during high-flow years estimated cyanobacteria blooms are infrequent, while during low-flow years bloom periods are extended and the water quality is poor. Investigations on other man-made lakes and river sections of the Thames River, and preliminary studies on natural lakes with differing trophic states show that LND may be a useful variable in all lakes and reservoirs where nutrient limitation switches from phosphorus to nitrogen during summer.
Selecting Water Disinfection Processes using Fuzzy Synthetic Evaluation Technique
Authors: Chowdhury Shakhawat , Champagne Pascale
Published: May 2018

Drinking water treatment strategies generally involve treatment processes such as screening, coagulation/flocculation, sedimentation, and filtration/adsorption followed by disinfection. Disinfection approaches include chlorine/chlorine (chloramine), granular activated carbon with post chlorine (chloramine), ozone/chlorine (chloramine), chlorine dioxide/ chlorine (chloramine), chloramine/chloramine, and ultraviolet radiation/chlorine (chloramine). However, comparative evaluation of these disinfection methodologies and their application to a particular source of water is rare. In this study, a framework for multicriteria decision making has been developed. Human health risk, cost, technical feasibility, and disinfection performance have been incorporated as the criteria for evaluation of the disinfection approach. A fuzzy synthetic evaluation technique has been incorporated where fuzzy triangular membership functions were developed to capture the uncertainties of the basic attributes. This paper compares three disinfection approaches: chlorination, granular activated carbon with post chlorination, and chloramination through a multistage hierarchy risk management model in which the analytical hierarchy process has been used to determine the relative importance of various attributes at different hierarchy levels. The evaluation process was found to be sensitive to the assignment of relative importance of the attributes. Chlorination was evaluated as the best disinfection approach in most of the cases.
Synergistic Benefits Between Ultraviolt Light and Chlorine-Based Disinfectants for the Inactivation of Escherichia coli
Authors: Rand Jennie L. , Shupe Gordon , Gagnon Graham A.
Published: May 2018

Ultraviolet light is increasing in popularity as a primary disinfectant in drinking water treatment because of its effectiveness against chlorine-resistant pathogens and lack of disinfection by-product (DBP) formation. Previous bench-scale studies have shown that there are possibly synergistic benefits in reducing heterotrophic bacteria when ultraviolet (UV) light is coupled with chlorine (Cl2) or monochloramine (NH2Cl). Additional experiments have demonstrated that synergy exists between various disinfectants in controlling numerous bacteria, viruses, and protozoan. Few studies, to date, have specifically investigated synergy with UV in combination with chlorine-based drinking water disinfectants including chlorine dioxide (ClO2), Cl2, and NH2Cl. This preliminary study looked at the effectiveness of seven disinfection strategies (UV, Cl2, ClO2, NH2Cl, UV/Cl2, UV/ClO2, and UV/NH2Cl) against Escherichia coli in a single-species system at various combinations of disinfectant dose and contact time. Spiked solutions containing E. coli were treated by UV alone, chemical disinfectant alone, or UV coupled with chemical disinfectant. It was found that the combined disinfection strategies achieved the highest removal. Data were additionally analyzed for synergistic benefits, and each combination had a positive result. Results suggest that drinking water utilities may see enhanced removal of bacteria and potentially other pathogens due to synergistic benefits when UV was used in combination with any chlorine-based disinfectant. However, more data are required to conclusively determine synergistic relationship(s) between UV light and chlorine-based disinfectants.
Inactivation of the Bacteriophage MS2 by the Ciliated Protozoan, Tetrahymena thermophila
Authors: Pinheiro Marcel D.O. , Power Mary E. , Butler Barb J. , Dayeh Vivian R. , Slawson Robin , Lee Lucy E.J. , Lynn Denis H. , Bols Niels C.
Published: May 2018

Because the range of biological mechanisms responsible for the inactivation of viruses in man-made and natural water systems is poorly understood, the involvement of the free-living ciliated protozoan, Tetrahymena thermophila, in viral inactivation was investigated. The ciliate was found to remove the bacteriophage MS2 when the phage and ciliate were co-incubated in a simple salt solution. MS2 was enumerated as plaque forming units (pfus). MS2 removal was achieved only by living and not formalin-fixed ciliates, and was blocked by treatments that impaired the formation of food vacuoles. These treatments were cytochalasin B and low temperature. When fluorescently labelled with SYBR gold prior to co-incubation, MS2 were seen inside Tetrahymena within vesicles that had the shape and size of food vacuoles. The number of pfus associated with Tetrahymena was low. This suggests that the engulfment of the phage into food vacuoles led to the inactivation of MS2, which is frequently used as a surrogate for poliovirus in environmental microbiology. In the future, a broader understanding of the capacity of ciliates to inactivate viruses could lead to methods for improving water quality through the manipulation of ciliate populations and activities.
An Assessment of Environmental Changes in Three Lakes from King's County (Nova Scotia, Canada) Using Diatom-Based Paleolimnological Techniques
Authors: Thienpont Joshua R. , Ginn Brian K. , Cumming Brian F. , Smol John P.
Published: May 2018

Paleolimnological approaches using sedimentary diatom assemblages were used to assess water quality changes over the last approximately 200 years in three lakes from King's County, Nova Scotia. In particular, the role of recent shoreline development in accelerating eutrophication in these systems was assessed. Sediment cores collected from each lake were analyzed for their diatom assemblages at approximately 5-year intervals, as determined by 210Pb dating. Analyses showed that each system has changed, but tracked different ecosystem changes. Tupper and George lakes recorded shifts, which are likely primarily related to climatic warming, with diatom assemblages changing from a preindustrial dominance by Aulacoseira spp. to present-day dominance by Cyclotella stelligera. In addition to the recent climatic-related changes, further diatom changes in the Tupper Lake core between approximately 1820 and 1970 were coincident with watershed disturbances (farming, forestry, and construction of hydroelectric power infrastructure). Black River Lake has recorded an increase in diatom-inferred total phosphorus since about 1950, likely due to impoundment of the Black River system for hydroelectric generation and subsequent changes in land runoff. Before-and-after (i.e., top-bottom) sediment analyses of six other lakes from King's County provided further evidence that the region is being influenced by climatic change (decreases in Aulacoseira spp., increases in planktonic diatom taxa), as well as showing other environmental stressors (e.g., acidification). However, we recorded no marked increase in diatom-inferred nutrient levels coincident with shoreline cottage development in any of the nine study lakes. Paleolimnological studies such as these allow lake managers to place the current limnological conditions into a long-term context, and thereby provide important background data for effective lake management.
Spatial Distribution and Characterization of Contaminated Soils in Riverbanks of Saint-François and Massawippi Rivers (Southern Québec)
Authors: Saint-Laurent Diane , Hähni Marlies , St-Laurent Julien
Published: May 2018

Des sols contaminés aux hydrocarbures (C10-C50) et d'autres contaminants ont été découverts récemment dans les berges des rivières Saint-François et Massawippi, entre les municipalités de Eustis et Drummondville (sud du Québec). Il est probable que cette contamination provienne d'un déversement accidentel ou illégal dont la source serait l'ancienne mine de Eustis située au abord de la rivière Massawippi. La couche contaminée se retrouve parfois à plus d'un mètre de profondeur des berges. Malgré qu'il existe de nombreux rapports gouvernementaux sur la qualité de l'eau de ce bassin, aucune étude sur la contamination des berges et des sédiments du lit n'a été réalisée le long des rivières Saint-François et Massawippi, même si ces rivières circulent à travers d'anciennes zones industrielles et minières. Cette étudie vise à évaluer la distribution spatiale de la contamination le long des berges et dresse une caractérisation du type et du niveau de concentration des hydrocarbures et autres contaminants (ex. métaux lourds). Les résultats obtenus indiquent que certaines berges sont davantage contaminées par des hydrocarbures (C10-C50), en particulier dans le secteur de Windsor. Les autres polluants (métaux lourds, BPC et HAP) indiques des faibles niveaux de contamination à l'exception de certains métaux (Cu et Zn). Pour les sites plus pollués, ils sont inclus dans les critère B et C qui présente certaines contraintes d'utilisation du sol en tenant compte des normes du Ministère du Développement durable, de l'Environnement et des Parcs.
Transport of Lithium Tracer and E. coli in Agricultural Wastewater Treatment Wetlands
Authors: Boutilier Leah , Jamieson Rob , Gordon Robert , Lake Craig
Published: May 2018

Agricultural waste must be managed effectively to protect surface and groundwater resources, as well as human health. Constructed wetlands can provide a low-cost environmentally acceptable method for the treatment of agricultural wastewater. An ionic tracer (Lithium chloride [LiCl]) and a biotracer (a naladixic acid-resistant strain of Escherichia coli) were injected into six pilot-scale constructed wetlands treating dairy wastewater: three surface-flow (SF) wetlands and three subsurfaceflow (SSF) wetlands. Each wetland was 3.9-m long and 1.7-m wide. Residence time distribution functions were calculated for each wetland to investigate the hydraulic behaviour of each system during winter and summer conditions. During the summer study, the mean residence times for SF wetlands 2, 4, and 6 were 12, 16, and 14 days, respectively, while the mean residence time for SSF wetlands 1, 3, and 5 were 23, 18, and 22 days, respectively. The longitudinal dispersion coefficients were in the order of 10-6 m2 s-1 for each wetland during the summer and winter. The mean residence time for SF wetlands 2, 4, and 6 during the winter study were 8, 10, and 10 days, respectively, while the mean residence time for SSF wetlands 1, 3, and 5 were 8, 9, and 10 days, respectively. E. coli effluent peaks often occurred prior to Li peaks, suggesting that bacteria may be motile within the wetland environment. This study suggests that dispersion is an important mass transport process in both SF and SSF wetlands. Long-term operation of SF and SSF treatment wetlands may cause reduced retention times and treatment efficiency due to organic matter accumulation and channelling. Cold winter temperatures may also increase the survival of bacteria within treatment wetland systems, decreasing the wetland's ability to reduce bacteria concentrations during the winter months.
Application of SCR Technology for Degradation of Reactive Yellow Dye in Aqueous Solution
Authors: Dehghani Mohammad Hadi , Mesdaghinia Ali Reza , Nasseri Simin , Mahvi Amir Hossein , Azam Kamal
Published: May 2018

The effect of sonochemical reactors (SCR) technology upon the degradation of reactive yellow dye has been studied and reported here. Sonochemical reactors (ultrasound irradiation) produce strong cavitation in aqueous solution causing shock wave and reactive free radicals by the violent collapse of the cavitation bubble. These effects should contribute to destruction as well as the decomposition of dyes. This research investigated the efficacy of sonochemical reactors for decolourizing reactive yellow dyes in aqueous solution. In this research, the influence of concentration, frequency, treatment time, and reactor power on the dye decomposition were investigated. The results obtained from the study carried out have shown that SCR can be used effectively for degradation of reactive yellow dyes. The results suggested sonochemical reactors provided maximum destruction, and 120 min treatment time at 130 kHz and 500 W were the most effective for the maximum degradation of reactive yellow dye.
Concentrations of Endotoxins in Waters Around the Island of Montreal, and Treatment Options
Authors: Gehr Ronald , Uribe Santiago Parent , Da Silva Baptista Isabel Fatima , Mazer Bruce
Published: May 2018

Endotoxins are a component of most Gram negative bacteria, and some cyanobacteria. They may be toxic to humans when inhaled or injected, but the effects are unclear when they are ingested. In fact, low concentrations may protect children against certain allergies. Data for endotoxins in Quebec waters are unavailable, hence this study mapped levels in the waters around Montreal, using two commercial test methods. The recently developed factor C method had a greater linear range and was more convenient to use than the widely used Limulus amebocyte lysate (LAL) method. Although the methods gave endotoxin values of the same order, a consistent relationship between the two could not be established. Endotoxin concentrations in the untreated waters varied from 32 to 1,188 EU/mL, comparable in the literature from pristine waters to wastewaters. Values were generally lower in the summer. Filtration is known to be partially effective at removing endotoxins, but the effects of disinfection are not well established. Accordingly, chlorination, ozonation, and ultraviolet light were tested for the destruction of endotoxins in water, at doses found during drinking water disinfection. While chlorine and ultraviolet light had minimal effects on endotoxin levels, ozone could achieve up to 60% reductions at Ct values (concentration x contact time) as low as 2.5 mg•min/L.
Influence of Polymer Selection on Nutrient Phase Separation for Waste Activated Sludge Thickening at Bench Scale
Authors: MacDonald Allan J. , Basu Onita D.
Published: May 2018

The use of polymers to condition waste activated sludge prior to thickening is a common practice at domestic wastewater treatment plants. In this study, the performance of various commercially available granular polymers was observed. Thickening by gravity belt thickener was simulated at the bench scale, and the thickened sludge and filtrate produced were examined. Laboratory analysis was used to determine the differences in nutrient chemical concentration in the thickened solids and filtrate produced by different polymers. By examining the content of nutrient chemicals such as total Kjeldahl nitrogen (TKN), ammonia nitrogen, and total phosphorous, this research showed that polymer choice could affect the chemical composition of thickened sludge and filtrate with respect to nutrients. Results showed that the total phosphorous and TKN concentrations in the thickened sludge and filtrate were affected by polymer selection, which suggested that the chemical loading on the plant due to filtrate recycle, and the nutrient content of thickened sludge delivered to the digester are affected by polymer choice. Polymer optimization studies that examine nutrient properties of filtrate and thickened sludge beyond the basic total suspended solids analysis may be advantageous to minimize recycling of these compounds into the filtrate phase.
Filtration du bleu de méthylène, du chrome hexavalent et de l'acide éthylène diamine tétracétique sur une membrane céramique d'ultrafiltration à base de ZnAl2O4−TiO2
Authors: Chahid El Ghaouti , Loukili Hayat , Tahiri Soufiane , Younssi Saâd Alami , Majouli Abdelhak , Albizane et Abderrahman
Published: May 2018

Dans ce travail, nous avons étudié la rétention du bleu de méthylène (BM), du chrome hexavalent Cr(VI) et de l'acide éthylène diamine tétracétique (EDTA) par une membrane ZnAl2O4−TiO2. Les résultats obtenus ont montré que cette membrane présente une charge résiduelle qui dépend fortement du pH. L'effet de la pression et de la concentration sur le taux de rejet des espèces filtrées est étudié. La rétention des espèces ioniques est due à un mécanisme fondé sur les interactions électrostatiques entre les charges portées par la membrane et les ions. Le taux de rejet du BM diminue avec l'augmentation du pH, une situation qui provoque une diminution progressive de la charge positive de la membrane. Dans le cas du Cr(VI) et de l'EDTA, un pH alcalin est favorable pour une bonne rétention car la charge membranaire devient moins positive, le chrome est sous forme de CrO42− et l'EDTA apparaît sous ses formes les plus anioniques. L'effet de la pression sur le taux de rejet des solutés a montré que la contribution convective domine aux fortes pressions et conduit à des rétentions maximales du fait que le flux convectif du solvant Jv augmente et vient diluer le perméat.
A New Approach in Measuring Rainfall Interception by Urban Trees in Coastal British Columbia
Authors: Asadian Yeganeh , Weiler Markus
Published: May 2018

Interception loss plays an important role in controlling the water balance of a watershed, especially where urban development has taken place. The aim of this study was to illustrate the importance of urban trees as a form of ‘green infrastructure’ where they reduce stormwater runoff and rainwater intensity. In addition, trees cause a delay in precipitation reaching the ground. Interception loss was studied in the North Shore of British Columbia. We applied a unique methodology for measuring throughfall under six different urban trees using a system of long polyvinyl chloride pipes hung beneath the canopy capturing the throughfall and draining it to a rain gauge attached to a data logger. Different tree species (Douglas-fir [Pseudotsuga menziesii] and western red cedar [Thuja plicata]) in variable landscape sites (streets, parks, and natural forested areas) and elevations were selected to ensure that the system adequately captured the throughfall variability. Interception and throughfall were monitored over a one year cycle for which the results of seven discrete storm events for coniferous trees from the District of North Vancouver during 2007 to 2008 are presented. Cumulative gross precipitation for seven selected events was 377 mm. Average canopy interception during these events for Douglas-fir and western red cedar were 49.1 and 60.9%, where it corresponded to average net loss of 20.4 and 32.3 mm, respectively. The interception loss varied depending on canopy structure, climatic conditions, and rainfall characteristics.