South Suburban Sanitary District Wastewater Treatment Plant (WWTP) Facility Upgrade Plan Summary

(Note: The following is from a plan summary created by the South Suburban Sanitary District (SSSD) for upgrades to their wastewater treatment to reclassify their discharge water. As you will see at the bottom, if SSSD is successful in getting funding these upgrades, there are benefits to the Klamath Basin on the whole, including for agriculture and for the Lower Klamath National Wildlife Refuge.)

The upgrades to the wastewater treatment plant are mandated by the Oregon Department of Environmental Quality (ODEQ) and are necessary to comply with new permit requirements that must be completed by October 2026. The existing lagoon system cannot meet the nutrient removal requirements prescribed under the new NDPES permit #100700.

If the new permit requirements were in place for the past 4 years, nutrient limits (nitrogen, phosphorus, ammonia) frequently and consistently would have exceeded the TMDL limits. BOD limits would have occasionally exceeded limits during dry season months and are projected to exceed more often as flows increase over the next 20 years.

The existing WWTP does meet discharge limits in its current NPDES permit, but future discharges would exceed the limits allowed under the new permit. As allowable discharge limits for phosphorus and nitrogen decrease due to changing regulations, and as the population served by the District grows, the current WWTP is not expected to meet the new discharge limits for nitrogen and phosphorus. This is expected to occur at the NPDES permit renewal date in October of 2026.

Upgrading the existing WWTP includes the installation of a moving bed biofilm reactor (MBBR) treatment system, disinfection improvements, recycled water capabilities, effluent pump station, biosolids processing facilities, influent pump station improvements, headworks improvements, and existing treatment lagoon rehabilitation.

The scope of work below describes the upgrades that will be performed:
• Moving Bed Biofilm Reactor (MBBR) Treatment System, MBBR Blower Building, MBBR influent heating system
• Suspended air flotation for algae removal
• Disinfection Improvements (UV disinfection assumed), with chemical storage space. Demolition or abandonment of existing chlorine contact channel and related facilities.
• Tertiary Filtration
• Effluent pump station (back to pond or to disinfection) and effluent cooling facilities (potential cooling towers, following analysis)
• Site electrical (new electrical service, transformer)
• New Engine Generator and automatic transfer switch.
• Recycled water capability (including filtration and disinfection, and pump station)
• New Biosolids for processing algae and tertiary residuals, including odor control for biosolids facilities
• Influent Pump Station wet well spray system

• Headworks improvements: One Replacement headworks screen (multiple rake type) and screening handling, and one new manual bar screen; Channel blower (replacement); Sump pump (replacement); Ventilation improvements
• SCADA system improvements
• Existing treatment lagoon rehabilitation (sludge removal) and improvements to existing lagoon dikes (potentially required following analysis).
• Major yard piping work to include: MBBR influent piping, MBBR effluent piping, and Algae and Biosoilds process piping to processing facility.

Cost estimates for these upgrades are approximately $83 million.

In addition to compliance with ODEQ’s new permit requirements, these upgrades will provide significant public benefits as well as benefits to fish and wildlife as the water discharged will be much higher in quality when discharged into Lake Ewauna, the headwaters of the Klamath River. The proposed improvements will also ensure that treated effluent from the WWTP will meet Class A for reuse by irrigators, downstream water rights holders, and/or by the Lower Klamath National Wildlife Refuge.