The Soldotna Utility Department is housed within the Soldotna Wastewater Treatment Plant.  The Utility Department can be reached from 7:30am-4:00pm Monday through Friday. After hours, weekends or on holidays, messages can be left in voice mailboxes through an automated answering system, which also lists emergency contact numbers for City services.

The City hired HDR Engineering, Inc. to perform a comprehensive water and sewer rate study. A comprehensive rate study typically utilizes three interrelated analyses to address the adequacy and equity of utility rates. These three analyses are a revenue requirement analysis, cost of service analysis and rate design analysis. View the rate study summary.

Water Distribution System

The Soldotna Utility Department operates four Class A ground-water wells that are capable of producing 2.8 million gallons per day. The ground water is disinfected with liquid chlorine. In three out of the four wells we are also adding a solution of aqua mag to help keep the iron in suspension to prevent the iron from collecting onto the inside of the distribution system pipes and sloughing off causing high dosages to the consumers. The City operates approximately 36 miles of distribution pipe. Within the 36 miles of distribution piping, there are approximately 1300 water service connections and 344 fire hydrants.

Sewer Collection System

The purpose of the collection system is to collect wastewater and transport it to the treatment plant. Residents and commercial facilities within the City limits generate wastewater. Waste is collected from 29 miles of sewer lines to the City's Wastewater Treatment Plant through 15 different lift stations for treatment and disposal.

The Soldotna Wastewater Treatment Plant provides sewage treatment service for approximately a population of 4,000 people. The design capacity is 1.2 million gallons per day with a maximum flow permitted by the NPDES permit of up to 1.08 million gallons per day. The plant removes on an average 96.4% of the biochemical oxygen demand (BOD), and 94.9% total suspended solids (TSS) removal. Waste from the process is transferred to an aerobic digester, then processed through a belt filter press, and ultimately transferred to the Kenai Peninsula Borough Soldotna Landfill.

Primary Treatment

The primary solids are removed with a mechanical filter screen, a manual bar screen and through the grit handling system located in the headworks building. The mechanical filter screen is automatically self-cleaning. It is capable of removing all materials larger than 5/8 inch in diameter, the manual bar screen serves as a backup to the filter screen. The discharge from the filter screen is discharged into the concrete screening channels leading to the grit chamber. The grit chamber is designed to remove heavy matter prior to biological treatment material lighter than the specific gravity of water. After the primary solids are removed from the process, the pH is adjusted between 12 and 12.5 units and hauled to the Kenai Peninsula Borough Soldotna Landfill.

Secondary Treatment

The primary effluent moves to the secondary treatment to the extended aeration activated sludge process. The purpose of the activated sludge process (aeration basins and secondary clarifiers) is to biologically stabilize the oxygen-demanding material present in wastewater with aerobic microorganisms air is supplied to these basins for the microorganism. Extended aeration activated sludge is an operational mode in which the activated sludge unit process is operated at a relatively long hydraulic retention time and sludge age. The number of aeration tanks in service varies depending on the volume of wastewater being treated for the proper detention time.

Mixed liquor enters the secondary clarifiers, which slows down the flow and allows the sludge to settle and produce a clear effluent. Scum is removed from the surface of the clarifiers and transferred to the digester.

The clear effluent then enters the chlorine contact basins, which are designed to have a 45-minute detention time at a daily flow rate of 1.02 MGD with both chambers in service. The decholorination process of the effluent takes place at the discharge pipe of the chlorine contact basins and the final effluent is discharged into the receiving water (Mile 20 Kenai River)

Solids Handling

A percentage of the returned activated sludge is transferred to the aerobic digester from the bottom of the clarifiers over a twenty-four hour basis after leaving the clarifier it becomes wasted activated sludge. The principal purpose of aerobic digestion is reduction of biodegradable solids, odor and pathogenic organisms. Aerobic digestion is a method of stabilizing sludge by aerating it in an open tank for an extended period. The solids are then pumped to the belt press.

The belt press is used to de-water digested, conditioned sludge to 17-20% solids. Reduction of the volume sludge by de-watering allows easy handling and disposal of the sludge. These solids are then hauled to the Kenai Peninsula Borough Soldotna Landfill.

Collection System

The Soldotna sewage collection system consists of the following:

Wastewater Treatment Plant

The wastewater treatment plant consists of the following:

Distribution System

Four ground-water wells producing from 800,000 gallons to 2.8 MGD per day with a liquid feed chlorination system and liquid aqua mag feed at each well.