Design of a new water treatment plant for the City of Saint John

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University of New Brunswick


A new water treatment plant capable of producing 75 ML/day of treated water for the East side of Saint John has been designed based on the request of our client. The proposed plant is capable of removing solids, dissolved organics, soluble metals, cryptosporidium, giardia, and viruses to all limits specified by Health Canada and the province of New Brunswick. The plant will also be capable of storing 33 ML of treated water on-site. These standards were achieved by utilizing a five-stage process, consisting of coagulation, flocculation, clarification, filtration, and disinfection. Among these stages, there are also the units involving chemical preparation, pH adjustment, and corrosion inhibition. The new water treatment plant will also collect all wastewater produced at the facility for settling in two large ponds. A mass and energy balance were completed for each separate stream, and based on the calculated flow rates and energy demands, a cost for each piece of equipment in the plant was determined. Overall, the fixed capital investment was estimated at approximately $29.5M, which includes all equipment, pumps, and a back-up generator. The mass balances were also used to determine annual chemical costs. In addition to the raw materials, utilities, labour, and miscellaneous yearly expenses were combined to calculate the annual operating cost of $8.7M. Furthermore, the grass root cost for the plant was determined to be approximately $42.3M, which will be the complete construction cost. To pay for the new facility, an annual increase of $80 will be applied to household water rates for a period of fifteen years. The new water treatment plant meets all of the objectives assigned by the client and is technically viable based on the economic analysis performed. This water treatment plant meets all requirements that are other wise necessary for economically feasible plants. Along with the new water treatment design, further investments should be made in metering systems and replacing all the pipes in poor conditions throughout the distribution system. This will encourage water conservation and ensure the water being distributed to the consumers will be the highest quality possible.