Joint Sewer Authority

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The Joint Sewer Authority (JSA) provides sewer services for the Towns of Silverthorne and Dillon and the Dillon Valley District, Buffalo Mountain Metropolitan District and the Mesa Cortina Water and Sanitation District.

The JSA operates the Blue River Wastewater Treatment Plant located at 26452 Highway 9 in Silverthorne, CO.

RV Dump

The RV Dump at the Blue River Wastewater Treatment Plant is open from 8:00 a.m. to 3:30 p.m. Monday through Friday, weekends and holidays may vary.

RV Dump Fee:

RV: $3
Bus: $5

Joint Sewer Authority Process

Follow the Joint Sewer Authority process below and learn how they treat water to make it safe for release into the Blue River.

Blue River Wastewater Treatment Plant Flowchart

Pretreatment

In pretreatment, grit, paper, and other large objects are removed from the wastewater. The wastewater flows through a mechanical screen that removes large objects from the water while washing the organic material back into the influent stream. The Rotomat compresses the water out of the screenings and dumps them into trash bins. The water is then aerated and the velocity slowed so that things like egg shells, coffee grounds, dirt, etc. settle to the bottom of the grit tank. The grit is collected at the bottom of the aeration chamber dewatered. Screenings and grit are then sent to the local landfill for burial.

Handy Tip: Don’t put coffee grounds and egg shells in the sink, add them to compost!

Aeration Basins

Secondary Clarifiers

Water flowing off the top of the aeration basin then flows into the secondary clarifier. Here the water slows again, so that heavier particles settle to the bottom. Lighter particles such as foam or scum float on the surface and are skimmed off the top and sent to the digester. Pumps draw the heavy sludge off the bottom of the clarifier. 50% to 90% of the sludge is returned to the aeration basin to reseed the bacteria, allowing the bacteria to remove more organic materials. The remaining sludge is sent to the digester and the clean water from the clarifier is then directed to the equalization pond.

At times to help with nutrient removal, the sludge is redirected to a re-aeration basin before being sent back to the aeration basin. This is done so that the air can be cycled on and off to improve the process.

Flow Equalization Pond

Pond Flows coming into the wastewater plant vary with the time of day and the number of people in town. When there are more people in town over weekends and holidays, there are higher flows. Flows also vary with the time of day, with an increase during the morning and evening hours when people are taking showers, and getting ready for the day or bed. At night, flows drop considerably. The equalization pond allows storage of water until the tertiary treatment process can catch up.

The flow equalization pond also provides a place for wildlife to coexist within Silverthorne. The pond attracts many water fowl that are local to the area as well as those migrating through.

Clarrifocculator

Sand Filters

Clean water from the clariflocculator enters the sand filter from the top. The filter contains several layers of specialty sands of different coarseness. As the water travels through the sand, the remaining particles or contaminants are trapped in the layers. The clean water travels out the bottom of the filter and into the chlorine contact chamber. The filter has a series of valves and pumps so that when the filter becomes dirty or plugged, the flow to the filter can be shut off. Pumps push water upward through the sand filter and backwash the dirt into a holding tank. Once the backwash has completed, the filter returns to normal operation.

Chlorine Contact Chamber and UV

The chlorine contact chamber is the final treatment process before releasing water into the Blue River. If needed, chlorine is injected in to the tank and given time to kill any remaining viruses and bacteria. Then the water is treated with sulfur dioxide to remove the chlorine. This two step process ensures that the water released onto the Blue River is safe to the aquatic plants and fish. Many plants are moving to ultra violet (UV) disinfection because it is effective and safer to use that chlorine.

Digester Thickener

The thickener is used to separate the sludge from the clean water. Essentially a clarifier, the sludge settles to the bottom of the thickener and is then pumped to the digester. As the sludge settles it creates a thick layer (blanket) on the bottom of the thickener. Using a sludge judge, you can measure the depth of the blanket layer and adjust the pump to maintain the blanket depth that works best to send thickened sludge to the digester.

Digester

In the aerobic digester, the sludge is mixed and aerated so that further reduction of the organic materials can occur. At this point the bacteria consumes most of the remaining organic materials and some microorganisms will begin to eat each other as the food supply dwindles. In the ideal situation, all that would be left is the inorganic material that is then sent to the centrifuge for dewatering. Our digester is covered with ground to hold heat to assist the digestion process. This heat will melt the snow and provide plants for the local wildlife to graze on.

Centrifuge

Wildlife at the Joint Sewer Authority

The Blue River Wastewater Treatment Plant is located on 15 acres next to the Blue River on the north end of Silverthorne. The site is partially wooded and has many wetland features and streams running through the property. Naturally, the site is visited by lots of wildlife.

ducks on pond owl in tree