Redcliff Sanitary I-I Investigation

Redcliff, AB

ISL was engaged by the Town of Redcliff (population: 5600) to provide an inflow-infiltration (I-I) investigation to combat issues in the Town's wastewater collection system, which included residential sewer backups.


ISL reviewed previous wastewater system evaluations before constructing and calibrating a varied dry and wet weather MIKE URBAN model. After reviewing the wet weather I-I rates using the model, we performed flow correction routines on the existing flow monitoring data.

Open House

An open house was held to gather historical sewer backup information, and surveys were sent out requesting information about I-I contributors, such as roof leaders, sump pumps and weeping tiles.

Smoke Testing

Smoke testing, in which sections of the sewer system are filled with non-toxic smoke to locate entry/exit points, was implemented to identify other sources of inflow and infiltration.

Complex System

Complex hydraulics and structures, such as split chambers, siphons and lift stations, were present in the system. To model these complicated systems, all sewers, manholes, gravity trunks and forcemains were imported into the MIKE URBAN model individually.

Final Report

A targeted CCTV inspection was completed to assess pipe conditions in critical locations. A comprehensive report detailing all findings and upgrading cost comparisons was completed for the Town.

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Nakoda Wastewater Treatment Plant Upgrades

Morley, AB

ISL was engaged by the Stoney Nakoda Tribal Administration to conduct a performance review and operational assessment of the Nakoda Entertainment Resort's Wastewater Treatment Plant.

Operational Concerns

Some of the operational concerns were plugged drum screen blinds, insufficient air scour of the membrane and membrane cassettes, surging permeate pumping systems and a less-than-expected lifespan of the membranes.


The operational assessment included a full evaluation of the headworks, wastewater tankage, membrane bioreactor, permeate flow, composite samplers, chemical containment and human-machine interface. A visual inspection of the membrane bioreactor tank showed that the aeration system was not functioning as optimally as intended.

Secondary Train

In the short term, we recommended introducing a second process train to provide redundancy so that, while maintenance was being conducted on one train, the flow can be treated through the second process train.


An extensive list of upgrades was provided to the client, along with a cost-versus-benefit analysis to help the client schedule priority repairs and upgrades.

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Hardisty Lift Station Upgrade

Hinton, AB

The mechanical equipment within the Hardisty Lift Station was plagued with ongoing operational issues, which required regular dismantling to remove material from the pumps. These issues, coupled with the age of the station and restricted access to the mechanical equipment at the bottom of the dry well, prompted the need to upgrade of the station.

Project Work

In collaboration with the Town’s Engineering and Operational teams, ISL reviewed operational data and updated the projected flows through the station from those originally stated within the Wastewater Master Plan. With an established and validated future station capacity, ISL developed a preliminary design from which a detailed design, cost estimate and tender documents were produced.

Coordinating Operations

One of the challenges faced by both the Town and ISL was coordinating operations between the existing lift station and the constructed station. A delicate balance was maintained to ensure the aging lift station continued to operate until the new lift station was online. During commissioning the operation of both stations was closely coordinated such that overloading of the collection system did not occur.

Finding a Location

Construction of the new lift station was challenging due to poor ground conditions (high degree of pit run) and limited space. As part of the design phase a slope study was also undertaken to fine tune the final location for the new structure.

Project Completion

The lift station was tendered and awarded in mid-2014, with construction completed and the new station online in October 2015.

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St. Albert Pump Station

St. Albert, AB

In 2008, the Alberta Capital Region Wastewater Commission (ACRWC) engaged ISL to design a solution for upgrading the existing St. Albert pump station facility, which was comprised of two interconnected and aging pump stations.

Meeting Capacity

One of the challenges ISL faced was that the combined pumping capacity of the existing facility did not meet the service levels that ACRWC currently required. Due to the condition of the existing facility, ISL recommended the construction of a new pump station that would not only meet the current needs but also be upgradable to reach the future capacity.

High Pressure Pumps

After an extensive hydraulic assessment, ISL determined that three dry-mount, submersible 730 horsepower pumps were needed, with room for two future pumps. A combination of soft starters and flow control valves were used to cushion the transfer between stop and running states, ensuring the pumps were not stressed when pumping against closed or near-closed valves.

Unique Design

With the support of Manasc Isaac Architects, the building was designed with an innovative 21 metre circular footprint atop a 17-metre deep sunken caisson. This design was put forth due to poor sub-soil conditions and a high groundwater table that precluded a conventional open cut excavation.

High Visibility

Located in a residential neighbourhood, extensive public and stakeholder consultation was conducted, as well as the creation of a 3D fly-through video. The generator building was designed to minimize noise levels for the ultimate 1mW facility. An ultraviolet odour control facility was incorporated into the design as three forcemains discharge at the site.

Open for Business

The pump station design was completed in June 2010 and was tendered in August 2010. THe pump station was officially opened in June 2014.

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60 Ave Sanitary Trunk Sewer

Grande Prairie, AB

For this project, a 800-metre long, 1050mm diameter PVC pipe had to be installed at a 0.07 percent grade paralleling a utility corridor between the Grande Prairie Golf and Country Club and an existing neighbourhood.

Resident Concerns

Local residents were very concerned about the need to remove mature poplar trees on the proposed trunk sewer alignment. These acted as a natural buffer between their backyards and the golf course. This component of the project required consultation with the golf club and with the neighbouring residents for final landscape design.

Public Consultation

Several open houses were conducted to explain the plan to replace the trees and re-landscape the area. Residents were shown how extensive landscape architecture services would be conducted for restoration of the acquired easement through the golf course property. By adding more decorative landscaping than previously existed, the project became highly acceptable to the golf course, the adjacent residents and the general public.

Tight Timelines

To meet the tight timelines set by the client, the majority of the trunk sewer was installed during the winter season. Also, most of the supplies, including bench manholes, were preordered ahead of time and stored until needed.

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