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Publications (89)
Low-elevation coastal zones are increasingly exposed to flooding due to the effects of climate change. Inundation can lead to groundwater and soil degradation through saltwater intrusion. In transitional coastal areas, such as the upper reaches of estuaries, where floodwater is relatively fresh, flood-derived sediment deposits may provide an overlo...
The historical drainage activities in Big Meadow Bog (BMB) on Brier Island, Nova Scotia have altered the hydrologic regime and physical characteristics of the wetland complex. The effect of restoration activities on water levels throughout the wetland complex was investigated on two different spatial scales: sitewide and within a focused study plot...
Understanding the mobility of small particles in geotextile dewatering applications is important when considering highly toxic sediments containing dioxins and furans. These contaminants are often strongly associated with organic matter that are colloidal in size. Microspheres have been used in the soil science research community for tracking the m...
Estuaries are vulnerable to oceanic and atmospheric climate change. Much of the research investigating climate
change impacts on estuaries is focused on saltwater intrusion within surface water due to drought and rising sea
levels, with implications for ecosystems and humans. Groundwater and soil near estuaries may also be influenced,
as estuary sa...
The fate and transport of non‐steroidal anti‐inflammatory drugs (NSAIDs) in soil are determined by various processes, and the complexity of the system lends itself to the use of computer simulation models to help understand it. This study demonstrated the first attempt to use empirical data from lab incubation and field studies to parameterize and...
Coastal defense structures (e.g., dikes, seawalls) protect vulnerable communities along marine coastlines and estuaries from the physical and chemical influences of adjacent water bodies. These structures are susceptible to overtopping or breaching by tides and waves, with risks amplified by climate change-induced sea-level rise. Repeated inundatio...
Coastal defense structures (e.g. dikes, seawalls) protect vulnerable communities along marine coastlines and estuaries from the physical and chemical influences of adjacent water bodies. However, these structures are susceptible to overtopping or breaching by tides and waves potentially amplified by climate change induced sea level rise. Repeated i...
Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used globally to treat and prevent illness. Biosolids change physico-chemical characteristics of soil and can affect the mobility of NSAIDs. A field-based lysimeter study evaluated the effect of three rates (0, 7, and 28 Mg ha-1) of alkaline treated biosolids (ATB) on the leaching potential...
An often-overlooked impact of rising sea levels is the concurrent rise in coastal groundwater tables, which can result in subsurface inundation of below-ground infrastructure. This is an important consideration for rural coastal communities, many of which rely on on-site wastewater treatment systems (OWTS). Subsurface inundation and flooding of OWT...
Over 50 years ago, a marine estuary was converted to a wastewater stabilization basin for treatment of primarily pulp and paper effluent. As a result, the basin was immediately converted to a “freshwater” environment and subsequently accumulated a thin layer of black, organic-rich sediment containing varying amounts of dioxins and furans, metals, p...
The paleolimnological method was used to decouple geogenic and anthropogenic metal(loids) contributions in a sediment stabilization basin (Boat Harbour) located in Nova Scotia, Canada. Boat Harbour has been impacted by industrial effluents discharged by a bleached kraft pulp mill (1967 to 2019) and a chlor-alkali plant (1971 to 1992). The former es...
Geotextile tube dewatering is a pre-treatment method utilized in the remediation of high-water content materials (i.e. sediments and slurries). However, given the association some contaminants (e.g. dioxins and furans, (i.e. PCDD/F)) have with particulate matter in these contaminated sediments, understanding the fate and transport of this particle...
Rapid and accurate delineation of contaminated sediments in marine environments is critical for the effective assessment of site risks and the development of appropriate remedial action plans. In this study, a new application of the ultraviolet optical screening tool (UVOST) equipped with electrical conductivity measurement (UVOST-EC) is proposed t...
Land application of biosolids is one potential source of pharmaceuticals and personal care products (PPCPs) into agricultural soils. Degradation is an important natural attenuation pathway that affects the fate and transport of PPCPs in the soil system and biosolids application could alter the process. The present study assessed the effect of indiv...
Residuals of antimicrobial products from anthropogenic uses can create a selective
environment in domestic wastewater treatment systems and receiving environments and contribute to the spread of antimicrobial resistance (AMR). On-site wastewater treatment systems are widely used for domestic wastewater management in rural and remote regions, but th...
The use of geotextiles in sludge dewatering applications has become a popular approach for many engineering projects. For contaminated sediments, the water quality of the resulting effluent is important to quantify, as it affects decisions on secondary treatment of effluent from dewatering. The purpose of this paper is to discuss a bench scale stud...
A paucity of literature has compared geotextile dewatering methods to more conventional dewatering methods (i.e. centrifuge, sedimentation) in the context of how geotextile dewatering will perform at reducing particulate matter in the dewatering effluent. Particulate matter is the primary source of inorganic and organic contaminants (i.e. dioxins a...
This paper presents a study conducted to assess the influence that a filter cake deposited on the surface of the geotextile has on the mobility of three metals (Cu, Pb, Zn) during filtration of a contaminated sediment. Two chemical additives (cationic coagulant and cationic polymer) were introduced to the sediment to increase the particle size and...
A field sampling program was undertaken to assess the variability of physical characteristics of contaminated sediments in a large (160 ha) effluent stabilization lagoon. The objective of this paper is to use this “field lab” as a basis for comparing different sampling techniques (i.e. discrete and composite) for remediation-based evaluations (i.e....
This paper presents statistical analyses of hydraulic conductivity data collected from an existing cement-based solidification/stabilization (S/S) system. The goal is to characterize the spatial variability of hydraulic conductivity and to examine sampling recommendations for the quality control (QC) program of that system to achieve target decisio...
Organic sediment contaminants (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans [PCDD/Fs] and polycyclic aromatic hydrocarbons [PAHs]) were assessed using secondary monitoring data from a former tidal estuary (Boat Harbour) impacted by historical industrial effluents. Spatiotemporal characterization of PCDD/Fs and PAHs in sediments...
The ability of lateral flow sand filters, used as on-site wastewater treatment systems (OWTS), to remove antibiotic resistance genes (ARGs), antibiotic resistant bacteria (ARB), and other relevant genetic markers (HF183, 16S rRNA, and int1) was assessed. Municipal wastewater was settled in a septic tank prior to loading into six pilot-scale lateral...
This paper presents results of a field sampling program performed to assess physical characteristics of contaminated sediments obtained from a stabilization basin (Boat Harbour) located in Nova Scotia, Canada. The goal of this research is to develop a rationale for selecting representative sediment samples for bench scale dewatering studies for fut...
Introduction: A bleached kraft pulp mill in Nova Scotia, Canada, has discharged effluent wastewater into Boat Harbour (BH), a former tidal lagoon within Pictou Landing First Nation (PLFN), since 1967 [1]. Fifty years of effluent discharge to BH has created >170,000 m3 of unconsolidated sediment, impacted by inorganic and organic contaminants (metal...
The use of geotextiles (i.e. geotextile tubes) in wastewater treatment applications is ever increasing. This paper examines the potential of using a geotextile to improve upon the treatment of aluminium present in a filter backwash water that is generated from a water treatment plant in Halifax, Canada. A field investigation to ascertain the distri...
Low impact development (LID) is promoted as a sustainable management practice for stormwater in urbanized catchments. While the positive effects of LID features on surface water hydrology and water quality have been investigated, less is known regarding their effects on aquifer recharge. The hydrologic model PCSWMM was coupled with the groundwater...
Naturally-occurring uranium can be found at elevated concentrations in groundwater throughout the world, with the potential to cause kidney damage in chronically exposed individuals. Empirical evidence shows that uranium mobilization can be enhanced in the presence of ions that are associated with leachate from construction and demolition (C&D) dis...
Since the 1960s, pulp and paper effluent has been deposited in the Boat Harbour, resulting in a large quantity of accumulated unconsolidated waste sediments (>170,000 m 3). In this paper, a review of relevant studies was performed for dioxins and furans TEQs (Toxic Equivalents) concentrations, which were compared to current Canadian sediment qualit...
A bleached kraft pulp mill in Nova Scotia has discharged effluent wastewater into Boat Harbour, a former tidal estuary within Pictou Landing First Nation since 1967. Fifty years of effluent discharge into Boat Harbour has created >170,000 m(3) of unconsolidated sediment, impacted by inorganic and organic contaminants, including metal[loid]s, polycy...
This paper presents the results of a laboratory study that evaluated the geotechnical and geoenvironmental properties of a manufactured aggregate derived from cement kiln dust (CKD). The aggregate manufacturing process involved accelerated carbonation technology (ACT), which was used to treat contaminated soils at trial scale. The process operates...
A bleached kraft pulp mill in Nova Scotia has discharged effluent wastewater into A'se'k (Boat Harbour), a former tidal lagoon within Pictou Landing First Nation, since 1967. Fifty years of effluent wastewater discharge into Boat Harbour (also referred to as the Boat Harbour Treatment Facility [BHTF]) has created large quantities of contaminated se...
A bleached kraft pulp mill in Nova Scotia has discharged effluent wastewater into A'se'k (Boat Harbour), a former tidal lagoon within Pictou Landing First Nation, since 1967. Fifty years of effluent wastewater discharge into Boat Harbour (also referred to as the Boat Harbour Treatment Facility [BHTF]) has created large quantities of contaminated se...
The long-term hydraulic performance of lightly cemented soils is critical to engineering applications such as water infrastructure and/or remediation systems. Unfortunately there is a lack of literature that has related hydraulic performance of lightly cemented compacted soils (~ 5%) after freeze/thaw cycling to the morphology changes that result f...
This paper presents an analytical approach to selecting the sample size required to achieve acceptable quality control in a cement-based “solidification/stabilization” construction cell program intended for the treatment–containment of contaminated soils. The proposed approach is based on the hypothesis test that the cell does not have an acceptabl...
In this paper, the performance and structural changes in cement-treated soils under influence of freeze/thaw (f/t) exposure are investigated. Specimens from plastic and compacted soil-cement mix designs were exposed to different f/t scenarios to study the influence of f/t dimensionality (i.e., one-dimensional versus three-dimensional exposure) and...
Wastewater stabilization ponds (WSPs) are common for wastewater treatment in remote Canadian Arctic communities. In this paper, two geotextiles of different mass/unit areas are examined as a potential biofiltration upgrade to existing WSPs in arctic summer conditions. The intended role of the geotextile is to provide additional treatment of municip...
Biopiles can be used to dispose of slaughterhouse residuals (SLRs); however, the fate of pathogenic bacteria (e.g., pathogenic strains of , ) in these systems is not well understood. The transport of these bacteria in water leaching from the biopile could represent a significant contamination source. This research examined the transport of Enteroba...
This paper presents a laboratory study that assesses the diffusive and sorptive parameters of three volatile organic compounds (benzene, ethylbenzene and trichloroethylene) though cured, monolithic soil-cement materials. A double-reservoir diffusion test setup is used to determine the effective diffusion coefficient (D e ) and distribution coeffici...
Cement-based solidification/stabilization (s/s) is a remediation technology that has been widely used for treatment of a range of contaminants. Currently, there is limited published data on changes in hydraulic performance of cement-treated materials subjected to cycles of freezing/thawing (f/t). Fourteen sets of tests were performed to examine the...
In this paper the impact resonance (IR) test method is used as a nondestructive tool to examine the curing progression, freeze/thaw (f/t) resistance, and healing potential of cement-stabilized soils. Resonant frequency (RF) measurements on specimens moist cured for up to 241 days indicate that the main portion of the hydration process is completed...
Sampling requirements for the quality control (QC) of cement-based “solidification/stabilization” (S/S) construction cells do not currently specify the sample size considering the accuracy of the estimated effective hydraulic conductivity of the cells from the samples, nor considering the risk associated with drawing the wrong conclusions about the...
The impact of particle shape on the angle of internal friction, and the
resulting impact on beach sediment dynamics, is still poorly understood. In
areas characterized by sediments of specific shape, particularly non-rounded
particles, this can lead to large departures from the expected sediment
dynamics. The steep slope (1 : 10) of the mixed sand–...
A total of 108 specimens were prepared to examine the hydraulic performance and strength performance of nine different cement-stabilized soils under unexposed and freeze–thaw exposed conditions. Specimens from each mix design were evaluated under two levels of curing conditions (i.e., immature versus mature). Hydraulic conductivity and unconfined c...
The impact of particle shape on the friction angle, and the resulting critical shear stress on sediment dynamics, is still poorly understood. In areas characterized by sediments of specific shape, particularly non-rounded particles, this can lead to large departures from the expected sediment dynamics. The steep slope (1:10) of the mixed sand-grave...
The objective of this study was to examine the potential for beneficial reuse of fly ash as a sorbent for benzene, trichloroethylene, and ethylbenzene in soils treated with cement (i.e., cement-based solidification/stabilization (S/S)). Batch testing was performed with soil–cement mixtures containing fly ash and compared with similar samples with h...
In Nova Scotia, Canada, contour trench disposal fields are the most common type of onsite wastewater system. In this study, two identical contour trench disposal fields were monitored for 3 yr to compare performance under gravity-fed versus periodically dosed loading conditions. Influent and effluent from both systems were analyzed for a suite of w...
In this paper a conservative tracer (tritiated water) is used to assess the diffusive properties of 14 different laboratory-prepared soil–cement mixtures. A single-reservoir diffusion test setup to determine the effective porosity (ne) and the effective diffusion coefficient (De) through saturated, monolithic, soil–cement materials is used to asses...
This study investigates naphthalene diffusion and sorption parameters for three soil-cement mixtures. Transient, double-reservoir diffusion tests were used to assess the effective diffusion coefficients and distribution coefficients for the three mixtures. Batch testing was performed to independently investigate the distribution coefficient. Effect...
Liner systems are increasingly being used to protect the environment from contaminated waste. At the same time, society is increasingly insisting on estimates of the probability that these liner systems will fail to achieve their design objectives, one of which is to limit hydraulic flow from the contaminated region to acceptably small levels. This...
This paper presents the application of a single reservoir diffusion test to determine both the effective porosity of a soil-cement matrix and the diffusivity of tritium through saturated, monolithic, cement solidified/stabilized wasteforms. Testing was performed on a laboratory mixture of cement paste, sand, and kaolinite. The influence of porosity...
Cement-based solidification/stabilization (S/S) is a widely used source-controlled treatment method for contaminated sediments. Increasingly, the technology is being used to remediate sites that contain high molecular weight organic compounds. The low level of organic content in cement-based S/S mixtures often creates a need for organic additives i...
On-site treatment of residential wastewater is important for rural and remote regions where centralized wastewater treatment may not be feasible. Sand filtration is a proven method for secondary treatment of septic tank effluent (STE) and can be an economical option where soil conditions do not favor the installation of a typical disposal field. Th...
Treatment wetlands can be a viable wastewater treatment option, especially in rural and remote regions where centralized wastewater treatment is not feasible. Bacteria fate and transport modeling within wetlands requires further development if they are to become a more reliable and predictable form of wastewater treatment. The goal of this paper wa...
The purpose of this paper is to measure hydraulic conductivities of a geotextile polymer coated GCL, permeated with water, with three different permeameters: constant-flow, fixed-wall single-ring (FWSR); flexible-wall (FW), and constant head, fixed wall double-ring (FWDR). All results, except for the samples tested with the FWSR were lower than 1.0...
Onshore thermal treatment of offshore drilling mud waste generates a mineral by-product, referred to in this paper as thermally treated drill mud waste (TTDMW). Environmental regulations can result in the generation of significant quantities of this material, and hence it would be beneficial from a sustainability perspective to identify a value-add...
This paper presents an analytical solution developed to estimate probabilities of failure or advective flux exceedance for the case of a spatially variable geosynthetic clay liner (GCL) situated over a spatially variable compacted soil liner (CSL). The risk of utilizing such a liner system is assessed relative to a regulatory compacted clay-based s...
Treatment wetlands can be a viable alternative for rural wastewater treatment where conventional centralized methods of treatment
may not be feasible. The seasonal treatment performance associated with two surface-flow domestic wastewater treatment wetlands
located at the Bio-Environmental Engineering Centre in Truro, Nova Scotia was investigated b...
This review paper provides an overview of waste management practices for typical livestock mortalities in Canada. Provincial guidelines and regulations are provided (if available) for these practices. It is shown that there is significant variation amongst provincial guidelines for livestock mortality management and these guidelines and regulations...
Cement kiln dust (CKD) is a fine-grained material produced during the manufacture of cement. Current reuse options are limited and the bulk of CKD not reused in the cement manufacturing process is sent to landfills or stored on-site. Due to the calcium oxide (CaO) content of CKD, it has the potential to be used as a replacement for lime in treating...
Bacteria fate and transport within constructed wetlands must be understood if engineered wetlands are to become a reliable form of wastewater treatment. This study investigated the relative importance of microbial treatment mechanisms in constructed wetlands treating both domestic and agricultural wastewater. Escherichia coli (E. coli) inactivation...
Cement kiln dust (CKD) is a fine-grained material produced during the manufacture of cement. Current reuse options are limited and the bulk of CKD not reused in the cement manufacturing process itself is sent to landfills or stored on-site. Due to the calcium oxide (CaO) content of CKD, it has the potential to be used as a replacement for lime in t...
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...
In North America, the rapid movement away from the direct discharge of water treatment plant (WTP) residual streams to receiving environments has resulted in considerable benefits to the drinking water industry in terms of enhancing environmental stewardship practices and supporting source water protection strategies. Over the past 20 years, applic...
Cement based solidification/stabilization (S/S) treatment of contaminated soils/waste has a long history of use in the United States. Recently Canadian utilization of this technology has increased. The purpose of this paper is to describe the basics of the technology, how the technology treats both inorganic and organic contaminants, the methods of...
Offshore oil and gas drilling operations generate significant amounts of drill mud waste, some of which is transported onshore for subsequent thermal treatment (i.e. via thermal remediation). This treatment process results in a mineral waste by-product (referred to as thermally treated drill mud waste; TTDMW). Bentonites are originally present in m...
Water treatment plants (WTPs) can produce significant amounts of residual solids (i.e. sludge) as a result of coagulation, flocculation, clarification, and filtration processes to treat raw source water. In North America, alum is a common coagulant used in this process, resulting in the requirement for disposal of significant amounts of alum residu...
In this study, the effect of phosphorus treatment on the aluminum leachability from alum residuals was investigated. The waste residuals generated from treatment of secondary municipal effluent, effluent from re-circulating biofilter, and aquaculture process water were used in this study. Toxicity characteristics leaching procedure (TCLP) tests wer...
The migration of contaminants through a 2.9 m thick compacted clay liner (CCL) for a landfill leachate lagoon is examined 14 years after construction. The clay liner formed the lower portion of the composite liner system but the geomembrane (GM) was found to have defects that had allowed leachate to migrate between the GM and CCL. Chloride, sodium,...
The potential improvement in the sorption of volatile organic compounds (VOCs) to bentonite used in Geosynthetic Clay Liners (GCLs) is examined for mixtures of bentonite and several organoclays or activated carbon. Results of batch tests performed with dichloromethane (DCM), 1,2-dichloroethane (1,2-DCA), trichloroethylene (TCE), benzene and toluene...
Test apparatus designed to examine volatile organic compound (VOC) diffusion through geosynthetic clay liners (GCLs) are described, together with procedures for evaluating the relevant diffusion and sorption parameters. Test results show that the rate of contaminant migration proceeded through the hydrated GCL in the decreasing order of DCM and DCA...
A geomembrane-compacted clay composite liner system used to contain municipal solid waste (MSW) landfill leachate for 14 years is evaluated. Field observations of the geomembrane revealed many defects, including holes, patches, and cracks. Physical, chemical, and mechanical tests conducted on samples collected from five different locations of the l...
The apparatus and procedure for performing tests to obtain inorganic diffusion coefficients for Geosynthetic Clay Liners (GCLs) are described, and the processes (diffusion, anion exclusion and osmosis) that can affect the interpretation of these tests are discussed. Results from several inorganic diffusion tests on GCL and bentonite specimens show...
The swelling characteristics of five different geosynthetic clay liners (GCLs) are examined. Results show that two thermally treated GCLs have similar swell properties but a third thermally treated GCL with bentonite impregnated in the cover geotextile swells to higher GCL bulk void ratios at stresses below 100 kPa. This is attributed to the unconf...
The diffusion coefficients deduced from GCL diffusion tests performed with 3 g/L to 5 g/L (0.05 M to 0.08 M) NaCl solutions decrease linearly with decreasing final bulk GCL void ratio. However, this diffusion coefficient is shown to be dependent on the source solution and, when the NaCl concentration is increased significantly, the diffusion coeffi...
The objective of this paper is to examine the influence of correlation length and hydraulic conductivity distribution on the probability of failure of a clay liner system. To achieve this objective, a two-dimensional (in plan) clayey liner system is simulated with a probabilistic modeling program, mrflow2d. The correlation length, variance, and mea...
ABSTRA~ A 1.5 mm thick HDPE geomembrane was exhumed from a landfill leachate lagoon after 14 years of service. The differences in geomembrane properties that arise from five different exposure conditions are examined. The paper demonstrates the importance of antioxidant and stress crack resistance towards the longevity of the geomembrane. Severe cr...
