Melville Water Supply System provides resilient, reliable, and cost-efficient drinking water to the city

Since its founding in 1908, the City of Melville in east-central Saskatchewan has endured challenges providing reliable, quality drinking water to residents. Melville's surface water supply was difficult to treat and the area is prone to droughts. As a result, the City added a supplemental groundwater supply in 1989.

The City implemented Canada’s first electrodialysis reversal (EDR) process to treat its highly mineralized groundwater supply. In 2016, with this equipment near the end of its service life, SaskWater, the plant’s owner/operator, retained Associated Engineering to design and oversee construction of a new water treatment plant using only groundwater.

Project Manager, Peter Hooge, says, "Associated Engineering shared SaskWater’s and Melville’s strategy and vision to use the reverse osmosis (RO) process to treat the groundwater supply for the City. Once completed, this facility would be one of the largest, municipal reverse osmosis water treatment plants in the province."

Associated advocated for the addition of pre-treatment upstream and post-treatment downstream of the RO, which would increase the RO membrane service life, reducing operating and maintenance costs and minimizing RO wastewater volumes generated.

SaskWater, Associated Engineering, and Beckie Hydrogeologists (BHL) collaborated on the design of the new wells, supply pipeline, and solar panel installation, which interfaced with Associated’s design of wellfield pumping infrastructure. Associated's multi-discipline team included civil, structural, mechanical, electrical, instrumentation and controls designers.

A complete SCADA (Supervisory Control and Data Acquisition) system was also part of Associated’s design, which interfaced with all components of Melville’s Potable Water Supply System. The project also included demolition of the old plant and the deep well injection system formerly used for EDR process wastewater disposal, and decommissioning of the surface water supply.

Project Engineer, Shengtao Weng, says, "We designed a tailored pre-treatment system, including oxidation, detention, and gravity filtration for removal of iron, manganese, and arsenic." The post-treatment system encompassed pH correction and saturation index adjustment (control water's corrosivity).

The new Melville Potable Water Supply System includes two new groundwater supply wells in the Hatfield Aquifer, located 30 kilometres south of the plant, a new raw water transmission line from the Hatfield Aquifer wellfield, re-use of two existing groundwater supply wells in the nearby Melville Aquifer and the associated raw water transmission line, a new water treatment plant in Melville, re-use of an existing 4550 cubic metre gunite reservoir, repurposing existing wastewater ponds, and potable water connections to the City distribution system and water tower.

Associated Engineering’s design allowed construction and commissioning to proceed without unplanned water supply service disruptions, while fully integrating existing non-plant infrastructure, where possible. Initially located adjacent to the old facility, the new plant design facilitated raw water and treated water piping interconnections, including a challenging connection into the existing gunite reservoir.

Peter tells us, "The new process incorporates wastewater retention and release, reducing environmental impact and greenhouse gas emissions from the former deep well injection system."

Melville now has the highest consistent quality drinking water in its 115 year history

The complete system, including the new 30 kilometre raw water supply pipeline, was successfully commissioned in March 2022. Operating costs are 20-25% lower than the old plant and maintenance costs are significantly lower.

Delivered on time and under budget, the water treatment plant provides Melville residents with affordable, high quality, sustainable, and reliable drinking water that supports growth, economic development, and quality of life.