The Great Lakes are the world’s most extensive freshwater system and are prone to cyanobacterial blooms. Different responses of cyanobacteria and their toxins to varying environmental factors highlight the importance of comprehensive monitoring programs, especially in Lake Erie, where the highest percentage of cyanotoxin occurrence has been observed. Microcystis mainly dominate cyanobacterial blooms in the Great Lakes, and microcystins are the most frequently detected toxins in surface waters and public water systems. The removal of cyanobacteria and their toxins using conventional and advanced treatment technologies has been studied extensively, with most of the studies conducted at the laboratory scale. The efficiencies of each treatment vary by toxin type, operational and water quality parameters, and each presents different challenges. This review provides an update on cyanotoxin levels in the Great Lakes region and discusses how environmental factors affect their occurrence. It also offers an extensive review of both laboratory and full-scale research on the effectiveness of commonly used treatment processes in Drinking Water Treatment Plants (DWTPs) for removing both intracellular and extracellular cyanotoxins, along with the limitations they face.

Removal of microcystin-LR (MC-LR) by ozone (O-3), vacuum-UV (VUV), and their combination was investigated in the presence of chloride as one of the main solutes present in water. In general, the combined VUV/O-3 process provided the greatest MC-LR removal, with the presence of chloride enhancing the removal efficacy. Formation of chlorine radical species was the primary reason for the observed improvement. The order of MC-LR removal by different processes using UV fluence of around 300 mJ cm(-2), ozone dose of 0.1 mg L-1, and chloride concentration of 120 mg L-1 was as follows: VUV/O-3/Chloride > VUV/O-3 > VUV/Chloride > VUV > O-3. Comparing MC-LR removal by O-3, VUV and VUV/O-3 in synthetic lab samples, spiked with Suwannee River NOM and natural water samples of the same organic concentration, showed the significance of background organics in scavenging ozone in the process. For a given ozone dosage, MC-LR removal by O-3 or VUV/O-3 in natural water was lower than that in the synthetic water samples. The standalone VUV was not affected and the MC-LR removals were identical in both synthetic and natural waters.

The efficiency of ozone treatment on the removal of three cyanotoxins in simulated Qatar tap water was evaluated. The reactivity of cyanotoxins with ozone followed the order as microcystin-LR (MLR) > cylindrospermopsin (CYN) > anatoxin-a (ANA). Approximately 70% of MLR, CYN and ANA were oxidized with an applied ozone dosage of 0.04 mg/L, 0.085 mg/L and 0.26 mg/L, respectively. Increased ozone dose greatly improved the oxidation efficiency, and a complete removal was achieved for all cyanotoxins. The level of pH affected the removal differently; highest removal rates were obtained at pH 5, pH 10 and pH 7.2 for MLR, ANA and CYN, respectively. There was no obvious effect of hydrogen peroxide addition on ozone treatment efficiency. Based on the calculated pseudo first order rate constants, the estimated ozone doses required for the 99.5% removal of 0.2 mg/L MLR, CYN and ANA were 0.12 mg/L, 0.22 mg/L and 1.3 mg/L, respectively.

The application of electrocoagulation (EC) as a standalone technology, as well as coupled with oxidative media filtration was investigated for the removal of arsenic and manganese from a community's groundwater supply. The effects of metal loading (ML), current density and flocculation time was investigated, in addition to the subsequent use of GreensandPlus (TM) filtration. Effective removal of arsenic was yielded to levels well below World Health Organization limits, with final concentrations below 3 mu g L-1, from an initial concentration of 9.77 mu g L-1. The optimal ML, or coagulant dose, was observed to be 10 mg L-1, with very little removal at MLs below 2 mg L-1. EC was not as effective for manganese removal, with only 10% reductions at an ML of 10 mg L-1. Further manganese reductions were yielded during flocculation, yielding a final total manganese concentration of 98.97 mu g L-1, below both the WHO and Health Canada maximum allowable concentration for drinking water. When coupled with oxidative media filtration, arsenic was nearly completely removed, with final concentrations below 0.1 mu g L-1. While the mechanism of arsenic removal was primarily associated with the iron coagulant floc formation, manganese removal was attributed to the catalyzed oxidation reduction reaction with the manganese dioxide media. Comparative studies using conventional coagulant resulted in arsenic concentration to decrease to 4.4 mu g L-1, over an order of magnitude greater than those achieved with EC.

The City of White Rock acquired the water system from EPCOR in October 2015. The City of White Rock decided to build a water treatment plant to treat the City’s existing groundwater supplies to remove naturally occurring manganese and arsenic to ensure that an improved drinking water quality is supplied to City residents that meets the Canadian guidelines and esthetic objectives. The City’s water supply is from groundwater wells located within the City municipal boundaries drawing from the confined Sunnyside Aquifer. There are seven operating, drilled wells. The Water Treatment Plant was built at the Oxford Pumping Station area. Construction of the Design Build water treatment plant (WTP) started in March 2018. The plant started operation in March 2019. The WTP treatment design objectives are to deliver drinking water meeting the following operational targets; Mn <0.02 mg/L, As <0.002 mg/L (95% of time, 0.005 mg/L for 5% of operation). All other water quality parameters shall meet the objectives of the Guidelines for Canadian Drinking Water Quality (GCDWQ) without treatment. The initial water quality data showed a significant removal of arsenic and manganese. However, after a few weeks of operation, the WTP performance for arsenic and manganese started to decline. Regeneration of the filter media was discussed with the contractor and manufacturer and implemented. The sequential regeneration of the four adsorbers was conducted successfully over a two-week period. Following the regeneration, arsenic concentration in the treated water effluent from the four parallel adsorbers was well within the water treatment plant Design Objectives of <0.002 mg/L. The staff of the Water Department worked to optimize the operation and make the changes needed to improve the performance of the plant.

The world is facing the third coronavirus caused pandemic in less than twenty years. The SARS-CoV-2 virus not only affects the human respiratory system, but also the gastrointestinal tract. The virus has been found in human feces, in sewage and in wastewater treatment plants. It has the potential to become a panzootic disease, as it is now proven that several mammalian species become infected. Since it has been shown that the virus can be detected in sewage even before the onset of symptoms in the local population, Wastewater Based Epidemiology should be developed not only to localize infection clusters of the primary wave but also to detect a potential second, or subsequent, wave. To prevent a panzootic, virus removal techniques from wastewater need to be implemented to prevent the virus dissemination into the environment. In that context, this review presents recent improvements in all the fields of wastewater treatment from treatment ponds to the use of algae or nanomaterials with a particular emphasis on membrane-based techniques.

The removal of cyanotoxins, microcystin-LR (MLR), anatoxin-a (ANA), and cylindrospermopsin (CYN) in Detroit River water (DRW) was investigated by ozone and advanced oxidation process (AOP). Enhanced removal of all cyanotoxins was observed with increasing applied ozone dose. The reactivity of cyanotoxins with ozone followed the order of MLR>CYN>ANA in DRW at its natural pH of 7.6, as indicated by the calculated pseudo first-order oxidation coefficients (kd) of 17.5, 7.41, and 2.03 L/mg, respectively. The most efficient oxidations of MLR, CYN, and ANA with ozone in DRW were obtained at pH 5, 7.6, and 10, respectively, with kd values of 29.5, 7.41, and 4.65 L/mg. Ozone-based AOP with hydrogen peroxide did not make a significant difference in the removal of cyanotoxins compared to the application of ozone alone.

A human health risk-based life cycle assessment (LCA) framework was developed for selecting low-impact water treatment systems with a focus on heavy metal(loids) removal. The framework comprises three phases, including pilot-scale water treatment, human health risk assessment (HRA), and LCA. The application of the framework was demonstrated by a case study. Two water treatment systems employing ozonation-greensand-ferric hydroxide-based sorbent (OGF) and Birm-ferric hydroxide-based sorbent (BF) processes were used to reduce arsenic and manganese concentrations in the source water of a small municipality in southwestern Canada. The heavy metal(loids) concentration as well as material and energy use data of the two systems were collected to perform HRA and LCA. The results showed that both systems can reduce arsenic and manganese concentrations; however, the removal efficiencies of OGF and BF processes decreased with the increase of treatment volume. At a constant inflow rate, the ferric hydroxide-based sorbent needed to be replaced every 31 and 25 days in the OGF and BF processes, respectively, to ensure that arsenic concentration in the effluent would not pose any significant human health risk. The LCA results indicated that the system using the OGF process generated lower life cycle environmental impacts than the system using the BF process throughout ten years' operation. It was also found that the arsenic removal process was the largest impact contributor in both systems. The manufacturing of ferric hydroxide-based sorbent and disposal of arsenic-contaminated treatment waste accounted for the highest impact in water treatment.

Ozone disinfection has demonstrated high efficacy against enveloped and non-enveloped viruses, including viruses similar in morphology to SARS-CoV-2. Due to this efficacy, numerous gaseous and aqueous phase ozone applications have emerged to potentially inhibit virus persistence in aerosols, surfaces, and water. This review identifies the exposure requirements for virus inactivation and important safety considerations for applications within the built environment (i.e. occupied/unoccupied spaces, air/water/wastewater treatment) and healthcare settings (i.e. ozone therapy, dentistry, handwashing, treatment of personal protection equipment (PPE)). Current research needs are presented to advance the utilization of ozone as a mitigation strategy.

The City of White Rock purchased the water utility on October 30, 2015, from EPCOR Utilities Inc. The City of White Rock's water utility provides safe and clean drinking water to its residents. The drinking water is obtained from the Sunnyside Uplands Aquifer. To ensure water supplied is of the highest quality, the City collaborated with the RES'EAU-WaterNET, to conduct research to evaluate and identify technologies that are capable of providing a significant reduction of arsenic and manganese, to improve water quality. The City submitted a grant application to the Clean Water and Wastewater Fund (CWWF) for the construction of a water treatment plant to reduce arsenic and manganese in drinking water. The Government of Canada and the Province of British Columbia provided funding from the Clean Water and Wastewater Fund (CWWF) to the City of White Rock for the "Arsenic and Manganese Water Treatment Project. The City awarded a contract for the Design Build for a Water Treatment Plant to provide a major reduction in arsenic and manganese in drinking water. The Design Build project utilized the scientific findings from the research conducted. The construction of the plant started in March 2018, and the project is expected to be completed by March 2019.

The City of White Rock, Canada has been facing challenges of elevated concentrations of arsenic and manganese in its drinking water supply. A pilot water treatment study was conducted to explore effective contaminant removal solutions for human health risk mitigation. The arsenic and manganese removal performance of four treatment processes, including ozonation-manganese greensand filtration (OSF), OSF-iron-based granular media adsorption (OSFIA), the Burgess Iron Removal Method (BIRM), and BIRM-iron-based granular media adsorption (BIA) were evaluated. The non-cancer health risks and the incremental lifetime cancer risks (ILCR) posed by arsenic in different water sources were also assessed. The results show that OSFIA treatment achieved the highest arsenic and manganese removal. An average arsenic removal rate of 68.5% (initial concentration = 9.3 μg/L) was observed using OSFIA during two months of treatment, while manganese (initial concentration = 133.9 μg/L) can be completely removed. The arsenic removal was mainly be attributed to the adsorption of iron-based granular media. The mean values of non-cancer health risks of arsenic exposure due to oral intake of treated water were identified to be lower than the critical threshold for different age groups. In addition, the probability of critical ILCR occurrence can be greatly reduced. Based on the results from the pilot study, OSFIA was selected to construct a full-scale water treatment plant. Arsenic and manganese concentrations in the effluent from the plant can be reduced to a low-to-undetectable level, achieving negligible health risks to the residents of the city.

Presence of cyanotoxins in drinking water poses a great risk to public health. Elevated levels of cyanotoxins in drinking water can lead to acute gastroenteritis, liver diseases, and neurotoxicity. In this study, drinking water samples were collected across the eastern part of Qatar and screened using a rapid assay to detect the presence of microcystins and nodularins. The results showed that the toxin concentrations in all the water samples were below the WHO prescribed limit of 1 mu g/L. Considering a worst-case scenario, toxin removal efficiencies were evaluated using ozone and ozone-hydrogen peroxide by spiking drinking water samples with microcystin-LR (MC-LR) at different oxidant dosages, toxin concentrations, water temperatures, and total organic carbon. It was found that peroxone-treated water samples have better MC-LR removal efficiency than molecular ozone at lower oxidant dosages. Nevertheless, at higher oxidant dosages, both ozonation and peroxone oxidation methods showed a similar removal efficiency. The experimental results also clearly indicated that variation in water temperature between 22 degrees C and 35 degrees C has minimal effect on the removal efficiency in both the treatment methods. It was also confirmed that the presence of organic carbon has a more profound detrimental impact than water temperature for toxin removal.

Ozone has proven effective in improving water treatment plant performance, increasing customer satisfaction, and meeting increasingly stringent regulatory requirements. The benefits include disinfection; reducing chlorine disinfection by-products; micro-coagulation; enhanced filter performance; biological filtration; oxidation of iron, manganese, sulfide, taste- and odor-causing compounds, pharmaceuticals and personal care products (PPCPs), and endocrine disrupting compounds (EDCs). Despite the effectiveness of ozone in water treatment, a perception remains that ozone may be too expensive for consideration at many water treatment facilities. This paper presents an evaluation by the Municipal Committee of the International Ozone Association (IOA-MC) that aims to provide a realistic assessment of the current capital and operating costs of ozone in the North American water treatment practice. A general strategy is proposed for developing preliminary estimates of ozone capital and operating costs that could be used by engineers and/or owners for planning purposes. The information presented may benefit utilities, managers, and engineers engaged in the evaluation of treatment options.

Investigation of source water quality is a key factor in selecting technologies to deal with certain water contaminants. Risk assessment and risk management are major tasks for drinking water systems engineers, managers and the regulatory agencies. Development of contingency plans are necessary to water systems, and having a multi barrier system is an approach started to become familiar to avoid any potential public exposure to water contamination that could have a serious impact on human health. Harmful Algal Blooms (HABs) are becoming a continuous challenge to the ecosystem and human health due to climate change, discharged nutrients from agriculture activities, improperly treated or untreated sewage effluents and others. Harmful Algal Blooms (HABs) are becoming a continuous challenge to the ecosystem and human health due to climate change, discharged nutrients from agriculture activities, improperly treated or untreated sewage effluents and others. The selection of certain technologies to deal with such challenge must take into consideration their impact on the sustainability of the water system. The successful applications of ozone and ozone based advanced oxidation process (AOP) gained major interest in mitigating challenges associated with cyanotoxins.

Qatar has one of the fastest growing and funded water sectors in the GCC region, with significant government funds being focused into water supply and sanitation. However, it is anticipated that there will be an increase in the demand on desalinated water supply due to increase in urban population and expansion of industrial and agriculture activities. This is expected to cause water shortages and a serious need for new water sources. There is a critical need to evaluate the efficacy of applying certain advanced technologies to improve the quality of Treated Sewage Effluent (TSE) for reuse in more applications in the industrial and agriculture sectors to reduce the demand on desalinated water. Treated sewage effluent (TSE) and wastewater have tremendous potential in supplementing the ever-growing water demand. It can be effectively recycled for both potable and non-potable purposes, provided it meets specific water quality requirement and type of application. Generation of treated wastewater is also cheaper and consumes lower energy when compared to desalinated water. Nevertheless, wastewater effluent contains a wide range of pathogens and other pollutants including chemicals of emerging concerns and heavy metals. Many studies have confirmed the abundance presence of pharmaceuticals, personal care products (PPCPs) and endocrine disrupting chemicals (EDCs) in wastewater that could pose a severe threat to public health. Therefore, it is essential that wastewater effluents are adequately treated and monitored to ensure a safe supply and reuse of treated effluents.

Pharmaceuticals and personal care products (PPCPs), endocrine disrupting compounds (EDCs) and disinfection by-products are suspected to have potential adverse impact on humans and hence their elimination during drinking water treatment is often desired or regulated. Based on pilot-plant experiments with three raw water sources, conventional treatment poorly removed the selected PPCPs and EDCs, while ozone/H2O2 and UV/H2O2 (both) with conventional treatment effectively removed PPCPs and EDCs. In most of the experiments, ozone/H2O2 + conventional treatment additionally removed THM formation potentials (THM-FPs) compared to those of conventional treatment. However, UV/H2O2 treatment was found to increase THM-FPs compared to conventionally treated water.

Although potential risk of pharmaceuticals and personal care products (PPCPs) and endocrine disrupting compounds (EDCs) and trihalomethanes to humans is small or unconfirmed, it is advisable to remove these wastewater-related contaminants to increase public confidence and acceptance as a precautionary principle and consequently their elimination or reduction during drinking water treatment is warranted. Experiments were conducted using the dual train pilot-scale conventional treatment plant with ozone and ultraviolet/hydrogen peroxide (UV/H2O2) with three different raw water sources. Reductions of trihalomethanes-formation potentials (THM-FPs) were 8–52%. Ozone was found to decrease THM-FPs while UV/H2O2 was found to increase THM-FPs in most of the experiments under experimental conditions. Conventional treatment poorly removed the selected PPCPs and EDCs while ozone + conventional treatment provided excellent removal. Conventional + UV/H2O2 treatment also demonstrated effective removal. However, removal of PPCPs and EDCs by conventional + UV/H2O2 treatment provided lower efficacy for Sites B and C, likely due to the presence of scavengers such as organics, bicarbonates, carbonates and particles.

Oxidation kinetics of selected pharmaceutical compounds and their degradation during ozonation of secondary treated municipal wastewater effluent (MWWE) was investigated. The apparent second-order rate constants for the reaction between chlorotetracycline (CTC), enrofloxacin (ENR), gemfibrozil (GEM) and ozone ranged between 6.82 – 52.7 × 104 M−1s−1. The measured second-order hydroxyl radical rate constants were several orders of magnitude higher at 8.4 × 109 – 13.1 × 109 M−1s−1 with a reactivity sequence of GEM > CTC > ENR. Overall degradation of CTC, ENR and GEM in secondary treated municipal wastewater effluent was >76 % at ozone doses of 0.33 mg O3/mg DOC or higher.

The aim of this study was to develop novel surface-modified poly(ether sulfone) (PES) ultra-filtration (UF) membranes for removal of endocrine disrupting chemicals (EDCs) and pharmaceutical and personal care products (PPCPs). Seven tailor-made charged surface modifying macromolecules (CSMMs) were developed for use as additives in the preparation of PES UF membranes with a greater surface charge and improved PPCP and EDC removal through charge repulsion. Twenty three types of PES membranes were prepared using two amounts of different CSMMs and two drying (or evaporation) times. The experiments were designed to obtain the membranes' performances in terms of normalized standard flux (NSF), molecular weight cut-off (MWCO), surface charge (SC), static contact angle and their removal efficiency towards one EDC (bisphenol A) and three PPCPs (carbamazepine, ibuprofen, and sulfamethazine). The correlation between NSF versus SC, MWCO, pore density, and porosity was discussed. The filtration experiments showed an initial partial removal of the target compounds, but no removal in the later stages of operation, which indicated that charge repulsion was not the controlling removal mechanism. This is consistent with small changes in membrane surface charge achieved by addition of these additives. Given the decrease in the percent removal with time, removal by size exclusion was also not significant as expected because the membranes had a MWCO greater than 10 kilo-Dalton while the target compounds had molecular weights in the 200 to 300 Dalton range. Based on the decreasing level of removal with time, it appeared that adsorption was the main removal mechanism.