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Wastewater Treatment


The existing plant was completed in 1986 at a cost of $2,190,396. The treatment uses a 6- stage aerobic process. Until an upgrade in 2011, the treatment used chlorine to ensure safe discharge into the Kootenai River. The maximum capacity of the plant is 1.5 million gallons per day, but the average is 450,000 daily.

The City recently implemented requirements of the DEQ concerning allowable levels of chlorine discharge into the Kootenai.  A new UV system was added in 2011 at a cost of $500,000 and now the plant can achieve outstanding removal of solids, nutrients and E.coli without the use of chemicals.

Another upgrade completed in 2011 was the purchase of a new sludge press.  This machine will allow the city to avoid the use of outside drying beds and the frequent odor accompanying the process. The cost of the machine and building to house it was $700,000.

In 2010 the Libby Wastewater Treatment Plant was the winner of the MWEA Small System Award.  The DEQ stated: “The performance of the treatment plant has consistently met the high standards established in the MPDES discharge permit for discharge to the Kootenai River.  Meeting these standards is critical to the protection of the environment and the public health.”

The plant is operated by a Main operator and 2-3 assistants.  An alarm system allows the plant to be maintained 24 hours a day by on call operators.

Why are sewer costs raised periodically?

Some factors which affect the cost of operating and maintaining the waste treatment plant are rising costs of chemicals, testing requirements, permit costs, utility costs and expensive upgrades to the existing system.  

What is the charge for opening and closing the city street for repairs?

There is a $15 fee for an opening permit that must be purchased at City Hall.  There is also a charge of $5 per square foot for openings into pavements and $2 per square foot for openings in alleys where there is gravel.  

Where does the property owner’s responsibility begin for their sewer line?

The responsibility for the sewer line begins at the city main in the street.  The property owner is responsible for the entire length of sewer from the main to the  their property.