PC – MBR Recommission – City of Bellevue, Idaho

Membrane Bioreactor Recommission

In March 2023 the plant failed. This was due to a compilation of reasons. This resulted in the structure flooding with over 20 feet of sewage. Which resulted in all electrical and pump failure.

Wastewater Treatment Plant Readiness Update

The Wastewater Treatment Plant is approaching startup readiness. Main equipment and the primary processing train (Train 1) are in good condition. Remaining are some small repairs, leak fixes, sensor replacements, and control system tests must be completed before the plant is fully operational.

Key Status Updates

Overall Readiness: Train 1 is ready to begin processing once prep work is complete. The main intake screens and holding boxes will be cleaned before startup to protect new membrane filters from debris.

Mechanical Systems: Motors, pumps, lagoons, and new membrane cartridges are ready. Technical adjustments are underway to tune air blowers for energy efficiency and to repair a noisy pump gearbox.

Sensors & Controls: A few sensors relating to monitoring and sampling are being replaced or recalibrated. System control experts will perform complete testing on automated controls and valves prior to launch.

Chemical & Disinfection Systems: There are still a few gaskets, and leaking fittings we are swapping out. We are also evaluating updated treatment methods to move away from Chlorine Gas to either sodium hypochlorite or UV.

Startup Plan: Startup will begin by introducing beneficial bacteria (seeding) into Train 1, gradually transitioning processing loads from the lagoons as system performance stabilizes.

Priority Action Items Before Full Operation

Clean Intake Equipment: Wash screens and remove debris to protect new filtration membranes.
Repair Pump Gearbox: Inspect and realign Permeate Pump 2 to fix mechanical noise.
Fix Chemical Leaks: Replace old O-rings, gaskets, and fittings across chemical supply lines.
Restore Sensors: Install and calibrate monitoring probes (dissolved oxygen, pH, turbidity).
Test Automated Controls: Bring automation specialists to test full SCADA and control system operations.
Optimize Chemical Treatment: Finalize disinfection plans and review cost-saving options for odor control.
Begin Plant Seeding: Add initial biological seed loads to Train 1 to prepare the system for full processing.

Membrane Installation

Membranes have been delivered and are installed.

Progress Towards Operating Conditions

City leadership has worked with operators and engineers to identify what is need to restore operating condition. Part way through the process new engineers were hired and an insurance claim filed to support recovery work. Every electrical panel had to be rewired, all of the motors and pumps needed to be replaced throughout the entire plant. All surfaces needed to be cleaned and sterilized. Initial from professional advice we thought the membranes would be able to be restored to get the plant operational. Unfortunately, this was not the case and wasn’t discovered until the original anticipated date. Upon this realization it was discovered that membranes are over 8 months delayed at the manufacturer. This timing was as we were entering winter 2025-2026 and called for the need to continue operating in emergency mode. Our continued diligently working within their ability and resources sanitize and keep operations functioning the best the situation provides.

Emergency Operation

The plant has been in emergency operation since the plant failure. The use of the lagoons has been the primary source for the plant since the failure. This extreme use of the backup system is taking it’s toll.

Plant Failure

In March 2023 the plant failed. This was due to a compilation of reasons. This resulted in the structure flooding with over 20 feet of sewage. Which resulted in all electrical and pump failure.