Proceedings of the Canadian Society for Civil Engineering Annual Conference 2023, Volume 8

In recent years, climate change-induced variations in the water and climatic cycle have led to increased frequency and intensity in the occurrence of floods globally. Floods can either eventuate as a result of intense storms or cyclones in coastal areas or by cloudbursts or prolonged monsoons in inland regions. Nonetheless, in both cases, these events affect people living in vulnerable areas more drastically. Flood vulnerability, in general, can be quantified in terms of impaired productivity, higher likelihood of infrastructure damages and economic losses, and displacement of local communities. Certain basins in the world are becoming exceedingly vulnerable to flooding either due to their geographic positioning or because of their disadvantaged socio-demographic circumstances. Some developing countries in particular are challenged by this more since a substantial proportion of their people live in densely populated cities that lie over a floodplain. For instance, about 70 million people in Bangladesh reside in flood-prone regions. Adopting effective control measures in these cases, consequently, becomes challenging both due to economic and physical constraints. Several basins around the world share this common trait, and hence studying the underlying similarities in the impacts of flooding in different global basins and their socio-economic consequences is important for targeting flood mitigation efforts. In this study, we use the data from the Emergency Events Database to study the mutual characteristics of flooding, their trends, and socio-economic impacts in selected river basins around the world (between 1990 and 2022). To do this, we employ both statistical techniques and a machine-learning classification model to delineate the common quantitative and qualitative features in the data. Our analyses results indicate that some basins are more vulnerable to flooding, and the vulnerable basins share similar features notably in terms of socio-economic impacts. We also highlight the recent drastic floods observed over the last 10 years, discerning their trends and impacts based on different geographic and demographic contexts. The results of this study offer a chance to understand the commonalities of flooding in different basins, and the discerned insights would enable the categorization of different basins to flood vulnerability in a better way, particularly from a socio-hydro-economy-centric standpoint.

Urban Water Systems (UWS) face significant material availability, waste management, and resource challenges. Applying the Circular Economy (CE) paradigm can enhance the sustainability of UWS by increasing water, energy, metals, and nutrient availability through resource recovery and system decentralization. The CE concept has been adopted in different UWS and management strategies; however, more research was needed on the application in Urban Water Management from a broad perspective, considering multiple studies and different CE strategies. Hence, this study uses a semi-structured methodology to identify the overall challenges and opportunities of CE applications in UWS and propose application strategies. The study identified many opportunities and challenges, such as the lack of integration among the different UWS that prevents CE from reaching its full potential and the possibility of recovering energy, nutrients, water, and metals in a unified system, reusing these resources on-site (e.g., reuse of metals to recover phosphorus). Another critical challenge is the rebound effect, which is rarely studied in UWS and has yet to be measured in UWS. Future studies should establish sustainability indicators and evaluate the sustainability performance of material use in UWS, aiming to develop sustainable solutions for each UWS.

Biogas is a clean and renewable source of energy, and its production from anaerobic digestion (AD) systems at municipal wastewater treatment plants (MWTPs) has become of greater interest to municipal environmental authorities and decision-makers given recent carbon pricing initiatives. Saskatoon Wastewater Treatment Plant (SWTP) is an advanced facility subjected to highly varying regional temperatures due to its location in Saskatchewan, Canada. Its AD systems stabilize sludges from thickened waste-activated sludge (TWAS), fermenter sludge (FS), and primary sludge (PS). Therefore, this study aimed to determine the optimum mixing ratios of TWAS, FS, and PS at the SWTP to enhance biogas production during AD processes. Extreme gradient boosting (XGBoost) was used to develop a data-driven-based model estimating biogas production rates using the input variables of TWAS, FS, and PS flow rates into digestors. The model performance was examined using root mean square error (RMSE) and coefficient of determination (R²). The developed model was then coupled with the Bayesian Optimization Algorithm (BOA) to determine optimum mixing ratios. Reasonable XGBoost model performance for biogas production estimation using all three inputs was observed (R² > 0.93, and RMSE < 0.53). Feature important analysis indicated that the model’s accuracy significantly relied on TWAS and was followed by FS and PS. However, the developed model using two inputs of TWAS and FS showed weaker performances. BOA then solved the XGBoost fitness function, and results showed the optimal digestor influent ranges were 6.4–6.8 L/s for TWAS, 3.0–6.0 L/s for FS, and below 4 L/s for PS translating to an approximate TWAS: FS: PS ratio of 48%: 23%: 29% per volume. Overall, data-driven modelling of the AD system and its optimization provides valuable, cost-effective, and accurate information, useful for more efficient AD MWTP design and management.

In this research, a traditional waste material that has been costly to handle will be used for beneficial purposes. Alum (i.e., hydrated aluminum sulfate—Al₂(SO₄)₃⋅14–18H₂O) is a common coagulant in drinking water treatment (DWT). The coagulation treatment inevitably generates large quantities of alum sludge, or water treatment residuals (WTR). The most common practices for WTR management are landfilling and agricultural application. Out of the concern of deteriorated soil quality, many producers are reluctant to apply WTR on their farms, whereas hauling the large quantities of WTR to landfills is also costly. Recognizing the major constituents in WTR, such as SiO₂, Al₂O₃, Fe₂O₃, and mono-/di-valent metal elements (e.g., Na⁺, K⁺, Ca²⁺, and Mg²⁺), as well as WTR’s own physical and chemical properties, this “waste” can be transformed into valuable products, such as construction materials (e.g., concrete and bricks) and ceramic materials. As a preliminary research attempt, we are using WTR-based ceramsites as an adsorbent material for pollutant removal from water matrices. They have demonstrated a good 24 h water absorption capability (9–63%), bulk density (438.79–829.80 kg/m³), and apparent density (720.83–1592.86 kg/m³). In this preliminary study, WTR-based ceramsite can successfully remove phosphate (PO₄³⁻) through adsorption process, achieving 90.05% removal in 69 h. More detailed studies are currently in progress to further investigate the possibility of WTR-based ceramsite to remove other pollutants, such as per-/poly-fluoroalkyl substances (PFAS). The preliminary experiments suggest the ceramsites have a potential to be used as a lightweight water filter media, particularly counting the benefits of solid waste repurposing. Our study will help the water sector reduce its operating expenses and generate new revenue opportunities and enhance its environmental stewardship.

The conversion of biowaste into biochar for use in water and wastewater treatment has gained significant attention in recent years. Activated sludge biomass as a by-product of biological wastewater treatment processes contains a high proportion of organic matter that can be converted into biochar. Biochar, as a carbon-rich, fine-grained, and porous substance, offers a dual solution for solid waste management and pollution control through the removal of contaminants from water when derived from sludge biowaste. This study investigates the feasibility of producing biochar with enhanced textural and adsorptive properties from activated sludge biomass through a one-step chemical activation process using zinc chloride (ZnCl₂) and microwave pyrolysis. The biochar produced was tested as a potential adsorbent material for the removal of a pharmaceutically active compound (PAC), lincomycin (LIN), from water. It was found that the structural and chemical properties of ZnCl₂-modified biochar (ZnBC) were significantly enhanced in comparison to raw biomass. The porous layered structure of ZnBC revealed an enhancement in the active surface area, which increased from 5 to 214 m² g⁻¹, and the average pore volume, which rose from 0.014 to 0.127 cm³ g⁻¹. Microwave pyrolysis resulted in a stable carbon-rich graphitized crystalline structure for effective removal of LIN. The results of the adsorption isotherm and kinetic models revealed that the adsorption process was controlled by both chemisorption and multilayer heterogeneous adsorption of LIN onto the external and internal surfaces of the ZnBC with a maximum adsorption capacity of 15.9 mg g⁻¹. Moreover, the presence of co-existing ions (NaCl) had little effects on LIN adsorption. Thermodynamically, LIN adsorption on ZnBC was more favorable at higher temperatures indicating an endothermic adsorption process. In conclusion, these results have significant implications for presenting biochar derived from sludge waste as a promising adsorbent for the removal of PACs from water in a sustainable manner.

The Nuclear Waste Management Organization (NWMO) is planning to develop a deep geological repository (DGR) for safe and long-term management of Canada’s used nuclear fuel in a stable rock formation 500 m below ground surface. Within a DGR, the used nuclear fuel will be encapsulated in an engineered barrier system (EBS), which will include copper-coated used fuel containers (UFCs) surrounded by highly compacted bentonite (HCB). A potential concern towards the long-term EBS performance is the production of bisulphide (HS⁻) by sulphate-reducing bacteria near the rock-bentonite interface. If produced, HS⁻ may diffuse through the bentonite and corrode the copper surface of the UFC. Although it is anticipated that sorption onto bentonite will restrict HS⁻ transport and minimize the risk of corrosion, the sorption phenomenon of HS⁻ onto bentonite has not been systematically investigated in the hydrogeochemical context of a DGR. To address this knowledge gap, this study designed laboratory batch experiments to investigate HS⁻ sorption onto bentonite under the influence of various conditions relevant to a DGR. As a part of this study, a literature review was conducted to select the factors that may influence the sorption behaviour. The study also required robust methodology development to build confidence in the experimental procedure. The preliminary results showed that sorption process required 24 h to reach equilibrium at room temperature (22 ± 2 °C). In addition, a minimum: (i) liquid-to-solid ratio of 100:1 and (ii) 1 ppm initial HS⁻ concentration were required to obtain detectable amounts of aqueous HS⁻ after sorbing onto bentonite. Considering the experimental constraints and the expected range of the key geochemical conditions in the DGR (e.g. temperature, pH, ionic strength), four sets of batch experiments were designed with appropriate quality control to explore the sorption phenomenon (including kinetics, isotherms, thermodynamics) under the key factors. While this study sheds light on the fundamental sorption mechanisms in bentonite; it also provides valuable guidance on sorption experimental methodology, which can be used in other environmental related research. Altogether, this study supports the broader, ongoing effort to assess the long-term EBS performance of Canada’s DGR.

Recently, the rise of fast fashion (FF) has created considerable more post-consumer textile waste (PCTW) in our municipal waste streams across the globe. Most consumers consider FF clothing and accessories as lower quality, and they will likely to dispose the products within a few seasons. During the past 20 years, the number of manufacturing companies associated with the textile industry and the average annual consumption of textile products have doubled globally. However, the generation characteristics and recycling behaviors of these end-of-life clothing are poorly understood by the scientific community. Proper PCTW management requires accurate description of both waste quantity and composition. Given their heterogeneous nature, the reusability and recyclability of PCTW are difficult to assess. Various blends of synthetic and natural fibers, plastics, metals, dyes, and adhesives are commonly used in a given piece of garment. Manual sorting of PCTW is typically required due to the drastic differences in clothing manufacturing process, fabric composition, cleanliness, and conditions. On the other hand, manual sorting requires specific training to sorters and is generally time consuming and expensive. The objectives of this study are to (i) review various textile sorting techniques on sorting of PCTW and (ii) examine the similarities and differences of the adopted methods and technologies. Data is collected from both scientific and gray literature. Keyword searches on various database are conducted, including Web of Science, Scopus, and Google Scholar. Preliminary findings suggest that Fourier transform infrared region (FTIR), near-infrared spectroscopy (NIR), and radio frequency identification (RFID) technologies are commonly adopted by researchers. The characteristics of the sorting methods are compared and examined considering technical, operational, and economical aspects.

The sustainability of effects from anthropogenic activities has gained significant attention in recent years. Traffic noise is a poorly understood source of such an activity on wildlife crossing structures, particularly in fragmented natural environments. Monitoring noise on wildlife crossing structures is complex since the source of the noise involves several concurrent moving sources, and testing such large source dimensions in the laboratory is not possible. British Columbia (BC) is home to 75% of all bird and animal species in Canada. Consequently, there must be a symbiotic relationship between the wildlife and the province's transportation system. This paper reviews the current level of knowledge and specifically the technologies and instrumentation that may be used for acoustic monitoring of animal crossing structures in BC. Additional innovations in monitoring instruments and innovative measurement techniques that can be successfully applied to wildlife crossing structures are suggested to monitor and mitigate noise in order to minimize its potential adverse impacts on crossing animals and improve the effectiveness of these structures for wildlife passage.

Natural disasters such as recent earthquakes have highlighted the importance of resilience against natural hazards as a key component of sustainability. Evaluating existing buildings under sustainable perspective requires the understanding of building’s life cycle stages exposed to these disasters. In comprehensive life cycle analysis (LCA) of a building, damage repair costs and downtime (economy component), environmental emissions and waste generation (environmental impact component), and deaths (society component) should be quantified and evaluated (Gencturk et al., Eng Struct 110:347–362 [1]). After an earthquake, the cost of damage repair and the resulting downtime can lead to negative impacts, including increased material and energy consumption and additional waste production. This is in addition to other significant impacts such as deaths and injuries. To mitigate these effects, researchers have adopted various approaches. They have evaluated the impacts on individual buildings in different forms and details, focusing either on the entire building or on specific building systems. In some cases, they have conducted comparative studies to assess the different impacts between two or more buildings, with the goal of optimizing a comprehensive model for a more sustainable structure. Most of the previous comparative LCA studies have been, however, applied to evaluate the environmental impact between two or more buildings without considering structural performance of the buildings. Recently, in addition to the environmental impact of the aforementioned conventional activities, researchers have attempted to incorporate seismic risks into traditional building LCA models and developed appropriate methods for comparing different design alternatives with respect to the impact of seismic damages and their recovery activities. The evaluation of five LCA studies, which took into account both the environmental and structural performance of earthquake-affected structural systems, will be the primary focus of this paper. The paper will also examine the main factors that influenced the assessment's findings and provide a summary of the most significant findings of them.

Antibiotics are widely used in human and veterinary medicine for disease prevention and treatment. However, a considerable portion of the administered doses are not metabolized or assimilated by animal or human bodies and are subsequently excreted in their urine and feces. In addition, antibiotics, as well as many pharmaceuticals, cannot be adequately degraded in wastewater treatment plants (WWTPs), given plant processes are typically designed to treat only easily and moderately biodegradable organics. Sulfamethoxazole (SMX) has been reported as the most often observed sulfonamide antibiotic in effluents of WWTPs. The current research aimed to prepare an agricultural residue-based biochar for the adsorption of SMX from water. Phosphoric acid (H₃PO₄) was used for biochar preparation as it is an efficient microwave activator. The activated biochar had a BET surface area of 1452 m²/g and showed a high SMX adsorption capacity of 181 mg/g. The adsorption site energy and its distribution based on the Freundlich model were estimated to describe the adsorption mechanism. The SMX molecules initially occupied the high-energy interlayer of the biochar before spreading to the low-energy active sites. Overall, the results indicated that microwave pyrolysis is an efficient method for creating an activating biochar adsorbent for removing SMX from water.

Microfiltration membranes are an effective and mature technology for water and wastewater treatment. However, membrane fouling is a critical operational challenge, involving the accumulation of colloids, organics, and the growth of bacterial biofilms on the membrane surface and within its pores, leading to permeability decline. Although membrane fouling has recently been simulated using mechanistic models, these models contain a large number of process variables with high nonlinearity and uncertainty. Data analysis techniques offer alternative effective approaches to describe membrane fouling under different operational conditions. They can also diagnose the causal relationships between the different process variables. In the current study, various data analysis techniques were applied on an industrial dataset, describing 141 full-scale water and wastewater treatment plants. These plants were categorized based on their influent water source, operational conditions, and membrane cleaning management. For example, it was found that most of the plants receiving their influent waters from surface water and wastewater sources are operated under “optimal” conditions. On the other hand, the plants treating groundwater are operated under “conservative” conditions. Moreover, the performance of the membranes in one of the surface water treatment plants was investigated under various operational conditions including several cleaning protocols. In addition, the specific flux decline and slope of specific flux loss were determined and evaluated under different cleaning management schemes to evaluate the membrane’s performance. The interdependencies between the process variables (e.g., cleaning chemical management) and membrane fouling rate are investigated to determine the governing factors in membrane fouling. Based on the results of the data analysis, it was found that an increase in the clean-in-place (CIP) intervals can reduce the slope of specific flux decline. In addition, when the interval of chemically enhanced backwash (CEB) increases, the specific flux recovery was enhanced during the cleaning cycles. The results can be used by decision-makers and water/wastewater treatment plant operators to reduce plant down-time by minimizing the frequency of clean-in-place (CIP) membrane cleaning procedures, while recommending the optimal frequency of membrane flux maintenance to minimize flux loss and rate of flux decline.

Due to its durability, low manufacturing cost, and versatility, plastic is a highly desirable product, and its production has been increasing over time. As such, the presence of plastic pollution in our environment also continues to increase. Plastic pollutants are categorized by size, and fragments that are smaller than 5 mm in size are considered microplastics. Microplastics are known to negatively affect wildlife and their ecosystems, and as the presence of microplastics increases in our environment, so too does the risk of humans ingesting or inhaling these particles. Thus, studying microplastics and their environmental effects is essential to mitigate the harm they cause to organisms, their habitats, and to humans. Specifically, modeling the movement of microplastics in waterways is a significant area of study that allows for informed decision-making in terms of cleanup efforts and policymaking. To study where a microplastic particles might accumulate, or where they might come from, researchers typically develop probabilistic models using satellite observations, field observations, and numerical models. These approaches are limited, however, because the resulting models cannot predict source–receptor relationships for future climate scenarios or microplastic conditions that have not been simulated in the building of the model. Recent advancements in computational technology have promoted the integration of automation into new applications, such as machine learning. The current research presents a machine-learning technique that was applied to a real-world case study to investigate microplastic source–receptor relationships in the St. John River Estuary in New Brunswick, Canada. The model was able to estimate the likelihood of microplastic particles accumulating in seven regions of the river in a timely manner was predicted, for microplastic particles that remained in the river domain, thereby supporting targeted cleanup operations and informed decision-making to manage microplastic exposure risk in the Saint John River Estuary.

Microbial fuel cell (MFC) systems in wastewater treatment processes have been the focus of extensive research due to their unique advantages of converting the chemical energy stored in waste to electricity while leaving low concentrations of nutrients in the effluent. While past studies have been extensively based on experimental studies, modeling and simulations are still sparse. Among all parameters and constraints inside and outside the MFCs, hydraulic retention time (HRT) directly influences the removal efficiency and operational cost. Finding out the relationship between HRT and the maximum voltage output of MFC will help future applications select a proper HRT to meet both economic and practical requirements. A MATLAB model is developed based on this purpose, and by setting other parameters as fixed, different maximum voltage outputs can be stimulated based on different HRT inputs. Four different cases under HRT of 6, 12, 24, and 48 h are simulated using the model. More results can be generated and compared using this model by customizing different variables after an acceptable HRT is selected for the MFC systems to determine the most efficient and sustainable condition for wastewater treatment.

The aviation fuel used by the Canadian Armed Forces is the single largest emitter of greenhouse gas (GHG) emissions in the federal family, contributing to approximately one-fifth of the government’s total emissions. In 2017, as part of the Greening Government Strategy, the federal government mandated the Department of National Defence (DND) to develop strategies to decarbonize their fleets. Historically, the CAF’s GHG emissions tracking has been focused on primarily financial tracking and recording total general fuel consumption. Due to this methodology, there are certainly areas whereby more strategic operations and fuel-related data can be targeted with a view to improving the robustness of the current database in this regard. Further, such data collection can be used to improve upon and optimize current ground operations of aircraft with the CAF by providing sound data to support management decisions. Information such as engine type, operating conditions, and other significant variables have direct effects on GHG emissions or aircraft but are not currently systematically collected. Using an initial case study as the backdrop, aircraft performance monitoring has commenced with a view to determining the current uses of fuel (in all phases of ground operations by aircraft) in order to establish a baseline of relevant fuel consumption. This paper highlights the methodology that was developed for this purpose as well as selected initial findings. Resulting trends will be used to populate a database, establish a baseline, analyze the data, optimize ground operations to achieve fuel efficiency, provide re-design options for the airfield and provide input to DND fuel policy. In this way, DND and the Royal Canadian Air Force (RCAF) in particular, is being proactive in addressing climate change as it is influenced by the production of GHGs.

Hybrid membrane aerated biofilm reactor process (HMABR) has been developed by integrating activated sludge process and membrane aerated biofilm reactor (MABR). It has shown promise by promoting simultaneous removal of organic matters and nitrogen pollutant efficiently due to the increased biomass content and improved mass transfer. Meanwhile, partial nitrification–denitritation in MABR could result in less oxygen consumption and carbon supply, lower CO₂ emission, less sludge production, and smaller volume of bioreactors as compared to conventional nitrogen removal processes. Further, synergistic benefits might be achieved through combining partial nitrification–denitritation with HMABR. Three MABR parallel experimental systems equipped with Zeelung™ membrane fibers were continuously operated to treat synthetic wastewater for 230 days. Up to 14% and 11% of influent NH₄⁺-N could be removed by nitritation–denitritation in HMABRs and MABRs, respectively. High organic loading coupled with insufficient gas scouring intensity accelerated the faster growth of heterotrophic bacteria in the MABRs than HMABRs, thereby, reducing nitrogen removal. Partial nitrification in both HMABRs and MABRs increased with the increase in ammonia loading and C/N ratio, while HMABRs demonstrated significantly better nutrient removal when high substrate loading rates were applied for MABRs.

The inappropriate disposal of wipes has caused severe sewer blockages in many cities, especially during the COVID-19 pandemic. To understand the transport mechanism of wipes in sewers, systematic experiments were conducted in a circular pipe using non-flushable wipes. The critical flow velocity for the incipient motion of wipes was found to increase with the decrease of the relative wipe size, starting from the value of 0.05 m/s. Non-dimensional equations were developed for characterizing the incipient motion using two commonly used parameters for particles: the critical Shield number and particle Froude number. The mean wipe velocity and the cross-sectional mean ambient velocity had a linear relationship. Different movement modes of wipes were observed and classified by using the transport stage number T*. The movement of the wipe started from the sliding mode. The rolling/saltation mode started at T* = 2.5, and the suspension mode started at T* = 12.6.

Statistics Canada announced that approximately 27% of dwellings still use heating oil. Therefore, it is inappropriate management, accidental spills, and occasional tank leakage in backyards have led to soil pollution. Nearly, 40% of all oil spills reported to the Ministry of Environment and Climate Change Canada annually originate from indoor or outdoor residential tanks. Oil tanks that leak can pose serious fire and environmental hazards, contaminating groundwater and private wells or other nearby drinking water supplies. Several techniques have been used to remediate polluted sites; nevertheless, they were found to be ineffective in small areas. Therefore, there is still a need to find an efficient and economical method for in situ or on-site techniques, which can be applied to small-polluted sites located close to building structures. Since the highest challenge in soil remediation is its clayey fraction, the present study aimed to investigate the feasibility of the electrokinetic application to soil media, which include various fractions of clay minerals. To determine soil–water–surfactant–oil system on electrokinetic phenomena and vice-versa, a series of lab tests were conducted using 3 different voltage gradients. Three different clayey soil matrices were contaminated with heating oil above the thresholds level (3600 mg/kg after Quebec regulations) and placed in open-air electrokinetic cells. An aqueous solution of an amphoteric surfactant, transported through soil due to electrokinetic phenomena, was applied as a washing system for 4 days. Then, soil and collected catholytes and anolytes were analyzed. The results showed that water and micelles mobility due to electrokinetic phenomena mostly attributed to electroosmotic flow. There was mobility in all combinations of power and clayey soil properties; however, the flow increased with the increasing clay fraction. Furthermore, studies demonstrated that effectiveness is limited to 2 V/cm due to high electrolysis pronounced at higher voltages. Additionally, zwitterionic surfactant with oil produces micelles which permit their transport toward both the cathode and anode.

Extensive bench and pilot scale research has demonstrated that UV advanced oxidation processes (AOPs) like UV/hydrogen peroxide (UV/H₂O₂) and UV/chlorine (UV/Cl) are dynamic systems where both UV dose and oxidant dose contribute to the generation of reactive oxygen species (ROS) and/or reactive chlorine species (RCS) that can degrade a wide range of contaminants, including many that cannot be removed through conventional water treatment processes. Non-target contaminants, including naturally occurring organic matter and inorganic ions, will also exert ROS and RCS demand, in some cases well beyond that exerted by the target contaminant. The demand associated with non-target contaminants is difficult to quantify and without understanding this demand, utilities may struggle to optimize their system. An external calibration method for quantifying this demand has been developed for UV/H₂O₂ and has led to the invention of a real time scavenging capacity monitor, but to date this method has not been demonstrated for other UV AOPs like UV/Cl. This paper presents cost curves which were developed by updating costing information published in USEPA’s Technologies and Costs Document for the Final Long Term 2 Enhanced Surface Water Treatment Rule and Final Stage 2 Disinfectants and Disinfection Byproducts Rule and USEPA’s Estimating Water Treatment Costs: Volume 2 Cost Curves Applicable to 1 to 200 MGD Treatment Plants. The cost curves illustrate the potential cost implications of different oxidant and UV doses for different AOPs, further highlighting the need for an efficient scavenging capacity monitor for UV/Cl. In addition, the preliminary steps taken to apply the external calibration method are presented in this paper, including the characterization of the UV lamp.

This research aimed to explore the impact of water quality parameters on the efficiency of UV disinfection in unfiltered and small drinking water treatment facilities. The study discovered that the absence of pre-treatment, such as filtration, can lead to an increase the degree of particle-microorganism (p-m) association. This association can decrease disinfection efficacy due to particles shielding the microorganisms from UV light. To investigate the impact of particulate type and concentrations on UV disinfection of unfiltered water, a range of water quality conditions at a bench scale was created by adding humic acid (HA), kaolin clay (KC), and iron hydroxide (Fe(OH)₃) to the raw surface water from two treatment plants. The composition or particle type of the turbidity-causing material was identified as the controlling factor in particle-microorganism association and UV response, especially when the turbidity level was low (less than 5 NTU). Analysis showed that zeta potential was the most significant predictor of UV inactivation in samples with elevated inorganic concentrations, making it a suitable measure of performance in treatment plants with high levels of inorganic particles. However, in samples with high organic content, turbidity was the most critical indicator. In summary, this study highlights the risks associated with UV disinfection of untreated water and provides insights into how to optimize UV disinfection in small or resource-constrained water treatment facilities.

Emerging micropollutants (EMs), including pharmaceuticals compounds, personal care products, and metals, have been continuously released into aquatic systems due to their lack of an efficient removal from the effluents in conventional wastewater treatment plants. Subsequently, these EMs require advanced treatment, e.g., sorption to decrease their harmful effects on human health and the environment. This study investigated an efficiency of filtration/adsorption process using biochar from in situ produced biosolids and industrial waste. Formulation of biochar and optimum operation conditions for scaling up the filtration system was determined by setting a prototype in lab scale. Adsorptive material preparation was optimized, and a fixed-bed column was designed to verify the performance of prepared adsorptive material under continuous flow filtration conditions. Then, the removal of micro and micropollutants was investigated. The designed biochar used for filtration/adsorption unit successfully removed 79.63% of SMX as a ubiquitous pharmaceutical compound in an aquatic system. Furthermore, metals such as Mn, Pb, and Zn were removed by 80.5, 50.2, 48.1%, respectively. Moreover, Bromide, Magnesium, Ammonia, Calcium, Nitrate, Chloride, Sulfate, Phosphate, Nitrite, Sodium was eliminated by 68.5, 42.9, 21.4, 18.9, 17.42, 15.53, 14.23, 12.5, 12.41, and 11.9%. The paper also provide scale up parameters, making the proposed system ready to be adapted to wastewater treatment plant.

Water resources are scarce in arid and semi-arid areas due to low rainfall and high evaporation, complicating water supply for domestic, industrial, and agricultural uses. Rainwater harvesting plays a significant role in successfully optimizing available water sources. In the same vein, the current study investigates the feasibility of a jute fiber-reinforced polymer tank as a 20,000-L rainwater harvesting structure. Jute fiber, being affordable with high mechanical strength, is a favorable substitution for synthetic fibers. The fabricating step for creating the tanks was: (i) erecting the framework, (ii) wrapping the form in jute ropes of 2, 10, 20, and 30 mm in thickness, and (iii) applying three coatings of an epoxy hardener mixture (10:1) both internally and externally. The base of the tank was fabricated separately and assembled with the tank. After 48 to 72 h and complete curing, the prototype tanks were filled with water to test for leakages and qualitative analysis. The stored water was tested qualitatively for pH, Total dissolved solids (TDS), water absorption, plastic migration, and ingestion hazard quotient (IHQ) of Bisphenol A (BPA) for 24 days. The reported pH and TDS varied from 8.06 to 8.544 and 736 to 995.739 ppm, respectively. The observed pH exceeded the 8.5 threshold value for the 2 mm rope specimen. However, the remaining specimens’ pH values were within the acceptable range. TDS, on the contrary, had values below the permissible value of 2000 ppm. An increasing trend in water absorption was primarily attributed to capillarity through voids and cracks, with a maximum reported value of 2.3%. The plastic migration test used two simulants, acetic acid and distilled water. Maximum recorded values were 0.1 mg/l, below the permissible value of 60 mg/l. The reported IHQ values for six age groups (6 to ≤ 9, ≤ 9 to ≤ 12, ≤ 12 to ≤ 18, ≤ 18 to ≤ 21, ≥ 21, and ≥ 65) were reportedly < 1, signifying the tank's safety. The suitability of the proposed tank was established following the preliminary experimental studies.

Sidestream treatment of dewatered anaerobically digested sludge liquor, referred to as dewatering centrate (or centrate), has gained interest in recent years since wastewater treatment plants (WWTPs) are required to meet stricter effluent nutrient limits while maintaining performance and stability of the mainstream process. This study investigated separate sidestream nitrification of centrate from a WWTP in Toronto, Canada, using activated sludge sequencing batch rectors (AS-SBRs). Two identical SBRs were seeded with return activated sludge (RAS) and operated with and without supplemental alkalinity in sequential batch mode on a 24 h cycle time at ambient temperature (25–27 °C) in the laboratory using a nitrogen loading rate of 0.18–0.20 g/L.d. Complete nitrification was observed in the SBR with supplemental alkalinity as ammonia–nitrogen (NH₃-N) removal during stable operation was 100 ± 0% (26th to 93rd day), while the SBR without supplemental alkalinity achieved 61 ± 2% (18th to 52nd day). Insufficient alkalinity adversely affected the performance due to the decreasing pH during the SBR cycle, which translated to incomplete nitrification and inhibition of ammonia oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). Results showed that addition of excess sodium bicarbonate (NaHCO₃) as a source of alkalinity during start-up extended the acclimation period. Furthermore, cycle activity test performed on the SBR with supplemental alkalinity during stable operation resulted in a nitrification rate (NR) and specific nitrification rate (SNR) of 23.21 mg N/L.h and 13.8 mg N/g VSS.h, respectively. Overall, this study confirmed complete nitrification of centrate and provided support in the development of a reliable sidestream treatment process.

Bromate is a probable human carcinogen which forms a disinfection by-product during ozonation, when water contains bromide. This study investigated the ability of cast iron granules to reduce bromate and compared their performance to nanoscale zero-valent iron particles (nZVI). In the experiments conducted, we observed a simultaneous decrease in bromate concentration and increase in bromide concentration. This observation was accompanied by a relatively constant total bromine species, indicating that bromate is directly reduced to bromide without any intermediates. The effectiveness of nZVI significantly decreased after 24 h, while cast iron granules showed a steady rate of bromate reduction. The capacity of cast iron to reduce bromate was also examined in multi-cycle experiments, and we observed that each gram of cast iron could reduce between 25.7–30.5 mg of bromate, depending on its initial concentration. Additionally, the results revealed that unlike nZVI, cast iron granules are not prone to forming an oxide layer which compromises the bromate reduction potential of iron particles.

Permafrost soils may have been polluted by pipeline spills due to the increasing rate of ice cap thawing as a consequence of climate change. Thus, an adequate treatment of such soil should be developed. This study aimed to investigate the feasibility of applying electrokinetic remediation to organic soil polluted with hydrocarbon in cold regions. A series of tests were conducted at 7 °C in electrokinetic cells (EK) containing 120 g of soil simulating peat properties. Synthetic soil samples consisted of 35% organic matter, 3% clay, and 62% sand. Soil samples were contaminated by toluene (40 mg/kg dry mass), as a hydrocarbon representative, above an acceptable level (Schedule II) of Quebec regulations. A soil electro-washing system with an average of 100 mL of surfactant solution/day was applied to mobilize pollutants toward the cathode or anode. Results showed the toluene removal in the liquid samples accompanied by some soil organic fraction (e.g., humic substances) during a 5-day test at a constant low voltage gradient of 2 V/cm. The observed removal of toluene in cold temperatures was many times higher than in an ambient temperature showing a high potential for electrokinetic remediation for cold regions.

Water treatment infrastructure is necessary to facilitate thriving human life, and as such, methods have been developed to ensure that water from various sources is made potable. One such process is the addition of metal salts, such as polyaluminum chloride (PACl), to the influent to facilitate particle coagulation and flocculation. This treatment process accounts for a large percentage of total particulate and turbidity removal from the water; however, the aluminum-based coagulation process yields sludge with high concentrations of aluminum as a by-product. Traditionally, the sludge is dewatered then shipped to landfill at the expense of the treatment facility. This places a financial burden on the treatment plant and incurs negative effects on the environment, such as leaching of metallic elements. Internationally, literature suggests that water treatment waste contains valuable chemical and mineral components which may be reclaimed and used to create a value-added product. Using water treatment residual (WTR) from the Buffalo Pound Water Treatment Corporation (BPWTC), which serves two of Saskatchewan’s largest cities, the authors will work in-lab to design a process to synthesize a viable product for future revenue generation. The most probable product choice is ceramsite, which is a heat-treated, porous material that can be used to remove contaminants from water. The WTR’s chemical composition lends itself to ceramsite creation, and the University of Regina possesses sufficient equipment to perform on-site experimentation and develop a product sample. Through our preliminary tests, the resultant ceramsite demonstrated the following physical properties: 24 h water absorption rate of 13–59% and compression strength of 0.26–18.57 MPa. Such results suggest that this waste-origin product can have high potential to be used for various beneficial purposes, such as adsorption media and construction material. This is deemed to be a noble and sustainable cause, as successful development of this WTR treatment process will divert sludge from landfill, directly protecting the local water table from potential metals contamination, while simultaneously abating the current expenses annually by BPWTP on sludge disposal.

Oil spills have become a major environmental pollution problem since the 1960s with the ever-increasing petroleum exploitation, transportation, storage, and accidental leakage of oil. Due to the influence of wind, water currents, waves, and temperature, the oil spilled goes through several chemical and physical changes. Oil spills kill aquatic organisms such as fish, shellfish, dolphins, whales, seals, and sea otters in addition to making seafood unsafe. Additionally, oil-covered birds pose a global environmental problem. Currently, efforts are geared towards recovering oil from oil spills and ensuring effective oil/water separation from the collected oil/water emulsion. The primary method for collecting spilled oil from aquatic environments is mechanical containment and recovery methods such as booms and skimmers. After oil recovery, adsorption is proposed to treat the residual oil in the oil/water emulsion to allow for safe disposal into the aquatic environment. Adsorption is an appealing treatment technology due to its simplicity and affordability. When the adsorbent is environmentally friendly and cost-effective, it makes it more appealing. Current research focuses on the optimization of adsorbent dose, adsorbent type, and contact time for enhanced treatment of oily wastewater in adsorption columns.

Process intensification in wastewater treatment plants (WWTPs) has become imperative to cope with the increasing amount of sewage, stricter environmental regulations, decreasing available footprint, and financial conditions. This study developed a plant-wide model for North Toronto Treatment Plant (NTTP) using BioWin. The model mimics NTTP’s performance under the current flow rate as well as plant rated capacity, and allows to take control actions to conserve the desired effluent quality. Documentation such as flows and lab data from online and offline sources was used to tune the BioWin model for the NTTP, and a series of steady state and dynamic simulations were run to calibrate and optimize the model. A four week sampling campaign, realized at the level of the primary effluent, allowed to overcome the sludge co-thickening modeling issue, and validate the steady state model with dynamic runs. Besides, State Point Analysis (SPA) was performed to examine the secondary clarifiers performance under current and future loading conditions. Five model configurations were implemented to the validated plant model and assessed to determine the optimized solution for plant upgrade to full treatment rated capacity, while keeping Environmental Compliance Approval (ECA) objectives conformity, and process cost efficiency.