Water treatment residual solids (WTRS) were characterized and studied as a potential phosphorus (P) adsorbent for application in sewage lagoons and stormwater runoff retention ponds. Three conventional WTRS sludge types (mixed Fe(OH)3-CaCO3, mixed Al(OH)3-CaCO3, and Al(OH)3) were collected from the Saskatoon, Prince Albert, and Buffalo Pound water treatment plants (WTP), respectively. The WTRS were collected in slurry form (i.e. not dried) from WTP clarifiers. Samples were collected during the summer and fall in an effort to observe seasonal effects. WTRS characterization involved determining selected chemical parameters which included pH, ammonium oxalate-extractable aluminum and iron content, and ammonium acetate-extractable calcium content. The pH of the WTRS samples ranged from approximately 6 to 8. Saskatoon WTRS samples had Feox content in the range of 55.2-55.8 g kg-1 of dry WTRS solid. Prince Albert WTRS samples had Alox in the range of 41.8-46.7 g kg-1 of dry WTRS solid. Buffalo Pound had Alox content in the range of 56.0-67.2 g kg-1 of dry WTRS solid. Saskatoon and Prince Albert WTRS samples had Ca content ranging between 34.3-38.1 g kg-1 of dry WTRS solid due to lime softening. Typically the fall WTRS samples had higher Al, Fe, and Ca content than the summer WTRS samples. Phosphorus adsorption behaviour and the maximum adsorption capacity of the WTRS were investigated through batch adsorption and settling experiments of WTRS in P-spiked deionized water. The Langmuir isotherm model best described the P adsorption behaviour of the WTRS (R2 = 0.97-1.00 linearized transformed data). The Freundlich isotherm model had not as good a fit with R2 ranging from 0.63 to 0.87 for the WTRS. The summer WTRS samples achieved maximum adsorption capacities (Qmax) in the following order: Buffalo Pound (78.1 mg P/g solid) > Prince Albert (70.4 mg P/g solid) > Saskatoon (7.37 mg P/g solid). The fall WTRS samples resulted in similar Qmax results in the following order: Buffalo Pound (82.0 mg P/g solid) > Prince Albert (70.4 mg P/g solid) > Saskatoon (6.41 mg P/g solid). Seasonal variations appeared to have minor impact on WTRS P adsorption. Phosphorus removal from sewage lagoons and stormwater runoff retention ponds was examined through batch adsorption and settling experiments of WTRS. Municipal primary wastewater effluent from the Saskatoon wastewater treatment plant (WWTP) was used as a surrogate for lagoon effluent during spring discharge. Stormwater runoff was collected from an agricultural runoff pond outside Saskatoon. Aluminum and iron based WTRS were effective at adsorbing phosphorus from municipal primary wastewater effluent in batch adsorption treatment. WTRS dosages removed P to within 6.4% of their target final P concentrations. However, the WTRS were not effective at adsorbing P from agricultural runoff water. After remixing the settled WTRS and doubling the dosage in the agricultural runoff water the WTRS only removed approximately 20-25% P. Re-suspension and resettling of WTRS after an initial cycle of P adsorption and settling had negligible effect upon the P concentration in the water column. The WTRS had a negligible effect on the pH of the wastewater solutions at the dosed concentrations. Short term (14 days) desorption of P from the WTRS utilized in P adsorption tests was low, typically less than 2% and reaching as high as 10.6% of the total P adsorbed. WTRS were found to be an effective P adsorbent from municipal primary wastewater effluent. The WTRS had high adsorption capacities compared to other WTRS and P adsorbents in the literature. The high adsorption capacities of the Al-based WTRS make them more practical than Fe-based WTRS for application.

The purpose of this research was to characterize the residual solids produced from hydraulic fracturing operations in the Marcellus Shale region. Four field samples were evaluated: drilling mud, treated sludge from the chemical treatment of process water, solids from the gravity settling of produced water, and sludge solidified prior to disposal in a municipal landfill. Cement kiln dust (CKD), used for solidification, was also considered in this study. All samples were subjected to a variety of laboratory techniques to determine their elemental composition and the potential for the elements to leach from the landfill. Strong acid digestion using a 3:1 combination of nitric acid to hydrochloric acid in a microwave with closed vessels was used to determine overall elemental composition. Leaching experiments were performed with de-ionized water and acetic acid (0.57%, pH 2.88) in an attempt to respectively evaluate the effects of weak and strong fluids that might be encountered by the residuals in landfill environments. Elements were analyzed by means of ICP-MS revealing the increased tendency for alkali metals, alkaline earth metals and halogens to leach. Leachablility was further increased for metals when exposed to acidic conditions. / Master of Science

The process of natural gas extraction through hydraulic fracturing produces large quantities of fluid containing naturally-occurring salt, radionuclides, and heavy metals which form residual solids during storage and treatment. The purpose of this research was to characterize the residual solids from hydraulic fracturing operations in the Marcellus Shale to predict the leaching behavior of select elements in disposal environments. Samples collected for this research were: (1) drilling mud, (2) treated sludge from the chemical treatment of process waters, (3) solids from the gravity settling of produced water, and (4) sludge solidified prior to disposal in a municipal landfill. These samples were subjected to various digestion techniques to determine the composition and leaching potential for elements of concern. Strong acid digestions were performed to determine the total environmentally available composition, whereas weak acid digestions were used to predict the leaching potential of these solids under various environmental conditions. The extraction fluids for the leaching experiments included weak acetic acid, acid rain, reagent water, and synthetic landfill leachate. Solids were agitated in a standard tumbling apparatus to simulate worst-case conditions based on ASTM and EPA recommendations. Results from EPA's Toxicity Characteristic Leaching Procedure (TCLP) were used to determine if solids were considered hazardous based on the metal leaching potential. The results from strong and weak acid digestions were compared to better understand the types and quantity of materials that have the potential to leach from the samples. This research may be used to develop best management practices for hydraulic fracturing residual solids. / Master of Science

Hydraulic fracturing operations utilized for shale gas production result in the generation of a large volume of flowback and produced water that contain suspended material, salts, hydrocarbons, metals, chemical additives, and naturally-occurring radioactive material. The water is impounded at drilling sites or treated off-site, resulting in significant generation of residual solids. These are either buried on site or are disposed in lined landfills. The objective of this study was to determine the levels of heavy metals and other elements of concern that will leach from these residual solids when placed in typical disposal environments. For this purpose, laboratory leaching experiments were employed wherein representative samples were brought into contact with a liquid to determine the constituents that would be leached by the liquid and potentially released into the environment. The samples used included sludge resulting from the physicochemical treatment of process water (TS), sludge solidified with cement kiln dust (SS), raw solids obtained by gravity separation of process water (RS), and drilling mud (DM). The samples were subjected to both single extraction (i.e. Shake Extraction Test, SET) and multiple extraction (i.e. Immersion Test, IT) leaching tests. For the shake extraction test, samples were mixed with a specific amount of leaching solution without renewal over a short time period. In the immersion test, samples were immersed in a specific amount of leaching solution that was periodically renewed over a longer period of time. For both these tests, analyses were performed on the filtered eluate. The tests were performed as per standards with modifications. Distilled de-ionized water, synthetic acid rain (pH ~ 4.2), weak acetic acid (pH ~ 2.88), and synthetic landfill leachate were used as leaching solutions to mimic specific disposal environments. Alkali metals (Li, K, Na), alkaline earth metals (Ba, Ca, Mg, Sr) and a halide (Br), which are typically associated with Marcellus shale and produced waters, leached at high concentrations from most of the residual solids sample. The SS sample, due to its stabilization with CKD, had a lower extraction efficiency as compared to the unconsolidated TS and RS samples. In EF 2.9 and EF SLL, the leaching took place under acidic conditions, while for EF DDI and EF 4.2, the leaching occurred in alkaline conditions. EF 2.9 and EF SLL were determined to be the most aggressive leaching solutions, causing the maximum solubility of most inorganic elements. Thus, high amounts of most EOCs may leach from these residual solids in MSW landfills disposed under co-disposal conditions. Agitation, pH and composition of the leaching solution were determined to be important variables in evaluating the leaching potential of a sample. The results of this study should help with the design of further research experiments being undertaken to develop environmentally responsible management/disposal strategies for these residual solids and also prove useful for regulatory authorities in their efforts to develop specific guidelines for the disposal of residuals from shale gas production operations. / Master of Science