Filter Media Replacement (WTP)

Between May and September 2024, SGWASA encountered water production issues at the water treatment facility related to the water filtering process. The five water filters struggled to maintain their normal production levels, unable to keep up with the heightened demand that resulted from the higher-than-normal temperatures. To investigate the issues with the water filter system, SGWASA contracted Hazen, one of its on-call professional engineering firms, to conduct a detailed examination. Hazen completed their detailed investigation and recommended the following improvements and optimizations for the filter operations at the SGWASA Water Treatment Plant (WTP):

Filter media replacement: The existing filter media is 22 years old, which exceeds the industry standard for media life of 10-15 years and should be replaced immediately.
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Rehabilitation of SGWASA Filters: The underdrain nozzles in the filter vessels should be further inspected and any failed or broken nozzles should be replaced.
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Consider Replacing Backwash Supply Pump: The existing backwash pump is not capable of achieving the needed filter media expansion of 30% to provide proper removal of solids
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Monitor Media Depths. Plant Operations should plan to monitor media depths annually to track media loss.
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Source Water Algae Monitoring Program. Since algae enumerations indicated the presence of known filter clogging species, a routine algal monitoring program beginning in 2025 is recommended.
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Modify the backwash procedure. To combat solids retention, it is recommended that the backwash procedure be modified to increase the duration of the high-rate portion of the water backwash.
Based on the recommendations contained in the technical report, SGWASA asked Hazen to develop a scope and fee for the filter media replacement project.