District reports manganese spike; staff to buy replacement membranes while studying Plant 1’s future

District operations staff told the improvements committee that a recent manganese "flare-up" at the water plant required immediate operational steps, an alert to vulnerable residents and a longer-term review of the Plant 1 membrane system.

"The highest influence that we got based on our in house testing was 1.34, which is extremely high," Travis said, describing in-house readings and lab actions after staff detected elevated manganese. He said vanFleck Tank and Rioso Tank readings remained below the 0.05 mg/L MCL for effluent, but with the spike staff put the plant to waste and increased chemical treatment while awaiting lab confirmation.

Travis described operational steps taken overnight: increased potassium permanganate dosing with chlorine after consulting a contracted chemical engineer, targeted sampling and conservative operational choices to avoid introducing unnecessary chemicals into the system. "I was gonna...put the plant to waste until we got this taken care of," he said, adding that staff issued a precautionary notice aimed at households with infants and the elderly.

Beyond the immediate response, Travis urged the committee to pursue a two-track approach: order replacement membrane modules to address imminent reliability and lead-time risks, while directing staff and consultants to produce a costed set of alternatives for the long-term configuration of Plant 1. He said he expects to spend roughly $900,000 to replace two membrane trains and noted modules and lead times are constrained: "If I order these within the next couple of weeks, can I get all 200 and something by December, maybe January?"

Committee members said they preferred a pragmatic stepwise approach: approve the membrane procurement (CIP-funded, to be placed on the board's consent calendar) to keep plants running and, in parallel, direct staff and consultant Joe to prepare three options — continue with membranes and better pretreatment, convert plant facilities to pretreatment and rely on Plant 2, or replace Plant 1 with a conventional treatment plant — with 30-year cost comparisons, land/use options and a recommended schedule.

Travis summarized the operational constraint: Plant 1, as built, provides good overall treated water but lacks pretreatment and contact time needed to consistently remove the district's manganese challenge. "I firmly believe that we need to get rid of Plant 1...and we need to replace it with a conventional treatment plant," he said, while acknowledging the need for studies and cost estimates before any demolition.

Staff also flagged technical issues that complicate short-term chemistry: the district's online meter registers potassium permanganate as manganese, making immediate in-house interpretation tricky, and the committee asked staff to identify better continuous online meters and emergency action-plan steps.

What’s next: Staff will seek a re-quoted membrane order, proceed with procurement under the approved CIP (Amelia to sign contract and staff to place on the board consent calendar), and prepare a refined options paper and questions for consultant Joe to study pretreatment, cost comparisons and feasibility for presentation at a future improvements committee meeting.

Why it matters: The incident highlights recurring manganese management challenges that affect water quality, staff workload, and capital planning. Committee members emphasized balancing immediate reliability with a deliberate, costed long-term solution.