Transforming Municipal Effluent into High Quality Water for Industry at Canada`s Largest Membrane Based Water Reuse Facility

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ABSTRACT
There is increasing demand for water in the Edmonton region as industry grows. With this growth, there is an increasing concern for water quantity and quality in the North Saskatchewan River. Alberta Environment is balancing water allocation with the need for responsible watershed protection. However, existing industries in the area including several petroleum refineries are facing increased water needs due to processing changes required by new regulations. The City of Edmonton is leading the way with solutions to some of these issues by making high quality water available from the Gold Bar Wastewater Treatment Plant (WWTP). In December 2005, Canada's largest membrane-based water reuse facility was ready to deliver water to its first industrial complex, the Air Products Hydrogen Plant feeding the Petro-Canada Refinery. The project is being phased with an initial water production capacity of 5 ML/d. The capacity will then be increased to provide up to 20 ML/d by 2008. Ultimately, the facility will be capable of producing up to 40 ML/d.

This paper describes the process that the City of Edmonton followed to develop a market for high quality reclaimed water and the subsequent needs definition, technology selection, facilities location and project execution. This process included piloting a membrane facility, a feasibility study, selecting a membrane technology, understanding design constraints and overcoming construction logistics. The arrangement called for the City to design, build, and operate the water reuse facility and for Petro-Canada to design and build a pipeline to deliver this water to its refinery. The total project was funded by Petro-Canada.

INTRODUCTION
Petro-Canada’s Edmonton Refinery Diesel Desulphurization and Refinery Conversion Projects include a new approach to managing water. Reclaimed water from the City of Edmonton’s Gold Bar WWTP is used in the production of hydrogen and steam, which in turn is used for the production of new low-sulphur diesel fuels. In the future, as part of Petro-Canada’s Refinery Conversion Project, reclaimed water will also be used processing alternate feedstocks, such as bitumen and bitumen-derived crude. This project has helped the City of Edmonton improve effluent quality at Gold Bar and continue along the path of responsible water management and environmental protection. The partnership between Petro-Canada and the City of Edmonton was an important component for this innovative project, a first in Canada. The following paper describes the water reuse project, from inception through regulatory approval, design, construction and commissioning.

THE CHALLENGE
The City of Edmonton’s Drainage Services Branch has as an objective in their business plan to maximize environmental protection. This objective has influenced the Branch’s operations, planning and visioning of future opportunities. As part of this future vision, Drainage Services has been working for many years towards a goal of water reuse from its Gold BarWWTP. This includes bench scale research on water quality for industrial reuse in the 1990s and operation of a pilot membrane treatment plant, starting in 2002.

The Gold Bar WWTP is located on the south bank of the North Saskatchewan River and provides wastewater treatment services to Edmonton’s population of about 712,000 residents and approximately 16,000 non-residential customers. The treatment plant has a design capacity of 310 megaliters per day (ML/d) or 82 million gallons (US) per day (mgd) with an average daily flow of about 290 ML/d (77 mgd).

In 2002, Petro-Canada announced its intention to modify their Edmonton Refinery for the desulphurization of diesel fuels to meet new Environment Canada regulations that came into force in June 2006. The regulation includes a requirement that sulphur concentrations be less than 15 ppm in diesel. By March 2004, Petro-Canada had signed an agreement with Air Products for the supply of hydrogen and steam for their new Edmonton Diesel Desulphurization (EDD) Project. In addition, Petro-Canada was assessing the potential conversion of its refinery to process alternative feedstocks, such as bitumen or bitumen derived crudes. The Air Product’s agreement included a number of conditions, one of which was the supply of raw water to the hydrogen plant fenceline. To meet this lower sulphur target, Petro-Canada needed to consume a significant quantity of water in the manufacture of hydrogen and steam that is then used to remove the sulphur from the diesel. This first phase, the diesel desulphurization step project, requires approximately 5 ML/d (1.3 mgd) of water to be supplied to the hydrogen plant. This water was required at the Air Products plant by end of December 2005. Phase two, the refinery conversion to process alternative synthetic crude, requires up to an additional 10 ML/d (2.6 mgd) of water for a total planned demand of 15 ML/d (3.9 mgd). This water was required at the Air Products plant by end of December 2005.

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