Capital Improvements Cut SSOs

North Olmsted tightens up its collections system and takes the fear out of heavy rain storms
Capital Improvements Cut SSOs
Jim McCutcheon (left) and Jeff Kohl carefully lower the CUES LAMP II lateral inspection camera down a manhole.

In the old days, when it rained, the North Olmsted collections crew would race out to surcharging manholes with portable pumps and work like mad to keep water out of customers’ basements. 

Today, they still go out during rainstorms, but only to monitor the flows and check on the effect of solutions they’ve put in place over the last three years to address the sewer overflow problem. 

“It was a real fire drill,” says collections system foreman Greg Peters, describing the previous situation. 

But now, thanks to a major $39 million capital improvement program, as well as ongoing maintenance and repair procedures, the North Olmsted team has the situation under much better control.

The underground

North Olmsted’s 37,000 residents are served by a separate sanitary sewer system that runs for 159 miles beneath this Cleveland suburb. Sewer lines, most of them installed between 1960 and 1974 as the city grew, consist of vitrified clay pipe ranging in diameter from 8 to 42 inches. The system contains 2,800 manholes and approximately 900 hydrants.

Five pumping stations power the system. Four are positioned around the city in relation to a natural divide that passes through the area, and all four pump into a main sewer line south of Lorain Road. A fifth station was added more recently to serve a new commercial development.

Wastewater flows to a conventional activated sludge treatment facility, designed to handle average daily flows of 5.5 mgd.

Peters and Assistant Superintendent Joe Auner and their team use a CUES LAMP II camera truck to televise and inspect the system, including laterals. The unit provides one-pass pan and tilt inspection of the mainline, with simultaneous inspection of adjacent laterals up to 80 feet. 

“We’re able to inspect 100 to 150 laterals a year,” Auner says. 

The North Olmsted team aims for a complete inspection of the system every five years. 

To clean the system and cut through root blockages, North Olmsted uses a GapVax MC Series combination jet/vac truck. The truck is a wet-only machine with a unitized water and debris tank and double subframe. The sewer district is divided into four wards and a portion of each ward is cleaned each year. “We’re right on schedule,” Peters says.

Issues and solutions

Located near the Lake Erie shoreline, North Olmsted gets wet. Rainfall in an average year is just over 43 inches. Annual snowfall exceeds 60 inches. Sudden storms can dump as much as 4 inches of rain in just a few hours. The precipitation can present the utility with serious inflow and infiltration issues. 

Following EPA orders that date to the 1990s, North Olmsted began an extensive sewer rehabilitation program specifically designed to combat the I&I problems that frequently turned streets into rivers and flooded residents’ basements. 

Completed in 2012, the project installed over 6,000 feet of new 12- to 24-inch-diameter relief sewer line alongside existing sewers, and another 900 feet of 15- to 24-inch relief sewer line alongside sewers in another section. Open-cut trenching was used, with little or no traffic disruptions. PVC pipe has been used for the relief lines. The existing pipes have been left in the ground for additional storage capacity. 

The project also rehabilitated the existing pumping stations and the added overflow equalization tanks. The 4.5 mgd LeBern pumping station and the 7.9 mgd Dover pumping station work included new Pentair - Fairbanks Nijhuis dry pit solids pumps, Endress+Hauser ultrasonic meters and Muffin Monster (JWC Environmental) grinders. The Clague Park pumping station was expanded from 270,000 gpd to 1.25 mgd. 

Perhaps the most significant improvement was the addition of equalization tanks to store sewer overflows and feed them back into the system during dryer weather. 

A 1.25-million-gallon underground storage tank was added to the Clague Park pumping facility. It fills by pumping and drains by gravity. A gravity fill and drain 360,000-gallon equalization tank was added to the Dover pumping station. 

Auner says the tanks have made a major difference, and although some overflows still happen during unusual storms, I&I has dropped appreciably since their installation. “They’re designed for the 15-year rain event,” he says. “After completion of the tanks, we’ve greatly limited the number of sanitary sewer overflows.” 

The LeBern work was completed in 2012, and the Dover phase in 2013. Bottom line? “Less reporting to EPA on bypassing,” Auner says.

Current maintenance program

Capital improvements are just part of the solution. Ongoing maintenance and repair are just as important to the success of any collections system, and Peters and his team work constantly to keep the sewers tight and functioning. 

Defective manholes and cracked pipes receive regular attention from North Olmsted’s in-house repair team. Manhole chimneys are regularly resealed using Elastomeric from Sauereisen; manhole covers repaired or replaced. Peters says the utility does about 100 manholes a year. 

Pipes are patched using trenchless technology, and the efforts have paid for themselves on the first two jobs, Peters says. 

It works like this: “After we camera a line, Joe and I review all the footage,” Peters says. “We try to concentrate on the major cracks — places where we have soil showing through. Then we use a Source One fiberglass mat as the patch with a two-part epoxy. We saturate the patch, then send it down the line and using a bladder, we inflate it against the inside of the pipe. Cure time varies from 90 to 200 minutes, depending on ambient temperature and patch type.” 

Once instructed in how to use the trenchless technology by supplier Source One, the North Olmsted crew does all the work itself. “It’s amazing,” Peters says. “We’ve got it mastered.” 

The utility can’t work on private property, of course, but Peters says his crew will patch lateral lines right up to the tee. 

“We can go right up to the customer’s line, and now with the new connections patching (recently made available), we can patch right around the connection.” 

Peters says trenchless has changed his crew’s workload. “It’s a big savings in time and cost,” he says, comparing it to the old days of digging and replacing. 

“The cost savings are enormous (with trenchless). We plan to stay on top of it.” 

Peters says the North Olmsted system has just a few root issues. “We have maybe 17 to 20 root areas,” he says. “We go out once a year and use the root cutter on our jetter truck.”

Checking it out

Few people actually venture out during rainstorms to see what’s going on, but the North Olmsted team dons wet-weather gear and heads out to observe the sewer system in action as the water rises. 

“We do our investigations during heavy rains,” explains Peters. “We have an evaluation sheet and we take a look at how various manhole locations along the system are functioning and identify the ones that might need attention — where bricks need replacement in manhole chimneys, or where there are bigger voids. Then, we use a cementitious filler (Sauereisen F-180 InstaPlug). 

“We like to catch them while they’re active,” he says. 

Two members of the staff also monitor flows before and after a manhole repair, using Hach flowmeters. “We go out once a week,” says Peters. “It’s continuous. We get the data back and we study it.”

Positive results

The data is showing results. “Before the repairs, if we had a 1-inch rain, we’d have overflows,” Peters says. “That’s gone away.” 

Also in the past are the “fire drills,” which were part of what Peters calls “a last-minute approach.” 

He says staff would watch the weather reports, then check known trouble spots. If a manhole started surcharging, staff would rush to the scene with portable bypass pumps and hoses to try to stay ahead of the storm and keep water out of basements. 

“It was time,” Peters says of the SSO issues. “This administration listened and stepped forward. The engineers and our operators have worked together (to address the SSO issue). We needed to take pumping off the streets.” 

He says the threat of emergencies is gone now. “We have some breathing room.”


Comments on this site are submitted by users and are not endorsed by nor do they reflect the views or opinions of COLE Publishing, Inc. Comments are moderated before being posted.