Pagosa Springs Sanitation General Improvement District approves purchase of pumps to address lift station problems — The Pagosa Sun

Wastewater lift station

From The Pagosa Sun (Chris Mannara):

At its regular meeting on May 5, the Pagosa Springs Sanitation General Improvement District (PSSGID) approved a purchase of $73,317 for additional pumps for pump stations.

Pumps were previously pur- chased in December of 2019 and have since been installed, Public Works Director Martin Schmidt explained during the meeting.

Since the installation of those pumps, however, they have seen failures and other issues, Schmidt explained.

The town ultimately got the assistance of its on-call engineer service, RG and Associates (RGA), to further investigate the problem and the town’s lift stations, Schmidt explained…

RGA, through its research, found that a series of things are causing pumps to fail, Schmidt explained.

Currently, staff is looking at prices for swing check valves to replace a ball valve pump control, he explained.

“That is something that really needs to be done no matter what else we do in this phased process because the current system creates a lot of dead head time,” Schmidt described.

According to Schmidt, “dead head time” is where pumps are pumping against a closed valve.

“For any pump system, there is an allowable amount of time that can happen, but because we have two 115 horsepower pumps, pumping in series, that time is shockingly short for our system,” he said. “Because we have so much power pushing against the valve, we need to get rid of that ball valve and put in something that opens when sufficient pressure is built.”

Other things the PSSGID can do with swing check valves is re- programming the PSSGID’s vari- able sequencing drives for slower startup and shutdowns, Schmidt added.
Additionally, town lift stations have seen cavitation from an in- correctly sized reducer, Schmidt explained.

“What it’s doing is it’s destroying the impellers, it’s destroying the wear plates,” Schmidt said, adding that cavitation causes main seals to be lost on the pumps.

In a follow-up email on Tuesday, Schmidt described cavitation as being caused by pressure changes in a fluid, which creates bubbles that collapse “violently.”

[…]

Part of the recommendation is to get a pump with an 8-inch inlet into the dry-well location, paired with the pumps purchased in December, he explained at the meeting…

Rebuilding and trying to fix the current pumps would put the price within $10,000 of buying a new pump that hasn’t had cavitation and other issues.

Additionally, rebuilding old pumps costs about $17,000 each, he added later…

According to Schmidt, the additional pumps will solve the cavitation issues in a single train at both lift stations.

“We spent $56,000 and change in December and because of a few different things, now we’re looking at $73,317 for a pair of pumps,” Schmidt said. “If you approve the purchase of these two pumps to- day, we still have four pump loca- tions that will be running pumps in some state of disrepair and not operating at full ability.”

According to RGA’s recommen- dation, the town would purchase those two pumps and then four additional ones, Schmidt added.

The motion to approve the pur- chase of additional pumps at the cost of $73,317 was approved via a unanimous vote of the PSSGID board.

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