AWWA ACE58260

In the late summer of 2002, a "no-use" water advisory was issued for the Town of Slave Lake (Population of 6,500). Residents were advised against using the Town supply for drinking or cooking. The water advisory was issued by the local health authority in response to high treated water turbidity levels that were caused by a high concentration of algae. Of specific concern was the potential presence of blue green algae. The water advisory simply punctuated the need for plant upgrade work to be undertaken to address various shortcomings. Based on the conclusions reached from pilot testing of ozone, granular activated carbon (GAC) adsorption, and microfiltration, a staged upgrade plan was adopted for implementation by the community. Stage 1 involves the implementation of improvements necessary to practice enhanced coagulation, address Giardia CT requirements, and maximize particulate and algae removal in the pre-treatment and sedimentation processes. Stage 2 involves particulate removal and disinfection system enhancements to address pending Cryptosporidium regulatory standards. This paper presents an overview of the unique challenges presented by this "high organic, algae laden" water source, the extensive pilot testing work undertaken, an overview of the water advisory nightmare and the challenges associated with integrating new improvements while keeping the existing facility operational. Includes 7 references, tables.