City wastewater capacity OK

By LAURA ROADY

Staff writer

BONNERS FERRY — Out of sight, out of mind is a common thought when dealing with wastewater until a problem arises.

Between population growth, increasing regulations and aging infrastructure, the Bonners Ferry City Council is trying to be proactive on the city’s wastewater facilities to prevent future problems.

Nearing completion is the city’s wastewater facility master plan which looks at issues affecting the city for the next 20 years.

“You have facilities that meet your needs,” said Brett Converse, JUB Engineers process design engineer for the master plan. “The system has remaining capacity but you are more than half way through the useful life.”

With a projected growth of 0.75 percent annually, the city could expect an additional 266 connections by 2033. One residential household is considered one connection and commercial businesses equate to several connections depending on size.

The wastewater system has enough capacity for that growth but infrastructure in both collection and treatment sections should start to be repaired said Converse.

Collection system

The entire collection system has nearly 122,000 feet of gravity line, 17,360 feet of pressure line, 476 manholes and eight lift stations as mapped out in the master plan.

Converse recommended repairing sections of line that are at adverse grades (following uphill) and inspecting all the gravity lines with cameras to assess their condition.

Also of concern is the main line crossing the river on the bridge.

If there is a failure on that line, the entire south side of town could be without sewer, said Converse.

The bridge, built in 1967, is in good shape but the pipe is aging explained Converse.

“A high priority to do something with that pipe, possibly two pipes,” said Converse.

Another concern are the lift stations. Of the eight lift stations, seven have remaining capacity and one has trouble managing peak flow.

Three lift stations are a high priority to replace for increased safety, reliability and capacity because of their high risk for failure, said Converse.

Bonners Ferry Water/Sewer Superintendent John Griffin’s biggest concern is accessing the lift stations to maintain them.

Currently, access is through a 36-inch shaft. Employees undergo extensive training to work in the confined space but new technology can eliminate that hazard explained Griffin.

New lift stations have wide openings, are easier to maintain and don’t require workers to go into the lift station for every fix.

Treatment system

If run properly, the wastewater treatment plant has the capacity for peak flows, said Converse. However, upgrades could be done to improve the efficiency of the lagoon.

Converse recommended adding a pre-treatment screening to the lagoon to filter out grit and items such as flushable wipes.

“It is less expensive to get grit out before the lagoon,” said Converse.

A pre-treatment screening would also reduce some of the sludge on the bottom of the lagoon.

Eventually the lagoon may need to be dredged to increase capacity but there is no bypass to stop the flow into the lagoon during dredging or repair.

A bypass would also aid in replacing the lagoon liner to prevent leakage. The lagoon is tested for leakage every ten years.

An ongoing issue in the lagoon in the summer is algae.

Chemical treatment and aerators work but with increased inflow, they may become costly. Currently, the city is spending $60,000 on chemicals to meet the algae discharge requirements of the EPA.

A solution is a membrane microfiltration system that filters the algae from the treated wastewater before it is discharged. An additional lagoon would not help with the algae issue said Converse.

“We are in a good position,” said City Administrator Stephen Boorman, of the current algae discharge. “We are discharging into a nutrient starved river. The algae is good for the river.”

Other recommendations for the treatment plant include security fencing, a storage area and a buffer zone. Converse recommended obtaining development rights or easements for at least 300 feet around the treatment plant to mitigate odor issues.

“A huge amount of the investment is driven by regulatory requirements,” said Boorman.

Payment options

“We know problems are on the horizon,” said Mayor David Anderson.

Fixing those problems comes at a price. The price to fix all the recommendations in the master plan would total $9.3 million.

A phased approach would stagger the costs and address the highest priority issues first, including membrane microfiltration, replacing the line across the bridge, buffer zones, security fencing, a portable generator (for a power outage), and the top three priority lift stations.

Phase 1 would cost $4.03 million.

Ultimately, the Bonners Ferry has to decide how to pay for the improvements. Boorman said it most likely will be a combination of bond financing and revenue financing.

According to the master plan, it is anticipated that a rate increase of $15.74 per month per user may be required to pay for these projects based on cost estimates and loan estimates.

To comment on the wastewater facility master plan, call or stop by Bonners Ferry City Hall.