Monoethanolamines (MEA) are commonly used by the natural gas industry to remove acid gases from the natural gas stream. A series of pan studies was conducted to examine the biodegradability of MEA in soil recovered from a gas plant site under various environmental conditions. Experimental results indicate that MEA was successfully biodegraded or transformed into other compounds under both aerobic and anaerobic conditions even at concentrations greater than 1500 mg/kg. Ammonium, acetate, and nitrogen gas were the dominant by-products in these experiments. The generation of nitrogen gas suggests that simultaneous nitrification and denitrification occurred because of the existence of anoxic zones resulting from diffusion limited oxygen transport into the soils. Cold temperatures (5 • C) reduced the biodegradation rates significantly compared to rates at room temperature.Résumé : Les monoéthanolamines sont fréquemment utilisées par l'industrie du gaz naturel pour retirer les gaz acides des courants gazeux. Une série d'études en laboratoire a été menée pour examiner la biodégradabilité des monoéthanolamines, dans les sols récupérés d'un site de raffinerie de gaz, sous différentes conditions atmosphériques. Les résultats expérimentaux indiquent que les monoéthanolamines ont été biodégradées avec succès ou transformées en d'autres composés sous des conditions aérobies ou anaérobies, même à des concentrations supérieures à 1500 mg/kg. L'ammoniac, l'acétate et le gaz azoteux étaient les sous-produits dominants lors de ces expériences. La génération de gaz azoteux suggère que la nitrification et la dénitrification surviennent simultanément en raison de l'existence de zones anoxiques qui résultent de la diffusion limitée du transport d'oxygène dans les sols. La basse température (5 • C) a réduit considérablement les vitesses de biodégradation par rapport aux vitesses à la température ambiante.

Monoethanolamine (MEA) is commonly used by the natural gas industry to remove acid gases from the natural gas stream. A series of pan test studies was conducted to examine the biodegradability of MEA in soil recovered from a decommissioned sour gas processing plant site. Test results indicate that MEA was successfully biodegraded or transformed into simple compounds under aerobic and anaerobic conditions. The electrical conductivity (EC) of the soil evolved with changing chemical conditions of its by-products during degradation of MEA. Based on experimental observations, five ranges of EC were correlated with five geochemical zones consisting of various concentrations of MEA and its by-products. The five ranges of EC were translated into equivalent in situ EC ranges. Using these in situ EC ranges, an electrical resistivity tomography image was used to create a geochemical interpretation of the subsurface beneath the plant site. The geochemical interpretation can provide useful information for detailed site assessment and remediation design.Key words: electrical conductivity, biodegradation, monoethanolamine, ammonia, acetate, electrical resistivity tomography, site characterization, observational approach.

In response to significant growth, the City of Calgary is currently building a third wastewater treatment facility, the Pine Creek Wastewater Treatment Plant (WWTP), to accommodate Calgary's immediate and long-term wastewater treatment needs. The first stage of this project will include a state-of-the-art 100 ML/day biological nutrient removal (BNR) wastewater treatment plant with tertiary filtration.Water is a "Newtonian" fluid, in which the pressure drop is proportional to the velocity and viscosity. However, most wastewater sludges exhibit non-Newtonian characteristics that are best modeled as Bingham plastics. The approach to modeling sludge flows described in this poster accounts for the much larger values of yield stress at low flow velocities.A Bingham plastic exhibits an initial resistance to flow, followed by a straight-line relationship between shear stress and flow. As the velocity approaches the transition to turbulent flow, it begins to show characteristics similar to Newtonian fluids. Each type of sludge resists movement with different intensity. Below the material's Yield Stress (Y s ), the Bingham plastic retains a solid-like matrix and no movement is observed. Above the Y s , the material will induce friction losses at a rate proportional to the shear stress as flow increases. In clean water, shear in proportion to shear stress is identified as the viscosity. For a Bingham plastic, the Coefficient of Rigidity (R c ) identifies this relationship.With municipal sludges, several factors affect the response of the sludge to shear stress. Solids content of the sludge is critical and is commonly used as a guide to selection of appropriate values for the yield stress and the coefficient of rigidity. The source of the sludge has also been demonstrated to have an impact on the selection of the rheological factors. Thickened waste activated sludge tends to have a higher yield stress and coefficient of rigidity than a thickened primary sludge of equivalent solids content.To gain a better understanding of the flow properties of the sludge at the Bonnybrook WWTP, the City of Calgary undertook sludge rheology testing to more accurately estimate pressure drop. Viscometer tests were performed to determine the viscosity of various sludge streams, at varying flow rates, to simulate both start-up and steady state conditions respectively.Because the Buckingham equation describes laminar flow, limits are placed on its use. A transition zone is defined by the upper critical velocity and lower critical velocity. The 3000 WEFTEC®.07

The City of Calgary (the City) recently commissioned a project to upgrade an existing cogeneration facility to maximize onsite electrical power generation and waste heat recovery using digester gas as the principal fuel source at the Bonnybrook Wastewater Treatment Plant (BBWWTP). The purpose of this system is better utilization of digester gas for generation of electricity and heat. The power generation and heating (PGH) facility upgrade replaced four obsolete combined heat and power (CHP) that were installed in 1984. A significant component of this project is the digester gas conditioning equipment. Digester gas typically requires some form of pre-treatment prior to cogeneration to remove siloxanes and hydrogen sulphides (H 2 S). Two new processes to North America were pioneered for the removal of H 2 S using an all biological scrubbing system and a molecular sponge siloxane removal system. The purpose of the systems is to reduce the corrosive and abrasive effects of digester gas used for generation of electricity and heat. This paper presents the results of the full scale implementation of these two novel digester gas conditioning systems including process design considerations, performance data, and recommendations for future installations.

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