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Fixing the Combined Sewer Overflow (CSO) Problem –
Ready or Not, Here It Comes
By Bobbi Holm

Omaha has been separating sewers for years, mainly in response to the problem of basement backups.  But now EPA/NDEQ, through the Clean Water Act, require Omaha to reduce the impacts of CSOs on tributaries of the Papillion Creek and the Missouri River.  In 2009, the city will submit their plan to reduce those impacts.

Omaha officials, with expert and citizen input, have chosen 3 major control projects (and lots of smaller associated projects).  The big projects are sewer separation in selected areas, building 3 high rate treatment plants, and digging a massive “deep tunnel” for storage and transport of overflows.  Sewer separation will be targeted for areas where it would be most cost effective.  Total sewer separation could solve the CSO problem, but is unbelievably expensive and honestly not doable in the time frame given for compliance.

High rate treatment plants would operate during wet weather and treat combined sewage close to the outfall.  These are projected to be storage and treatment facilities that can be designed to blend into the neighborhood.  Inflow from smaller storms would be captured, stored, and subsequently treated at the wastewater treatment plant before discharge.  Larger storms would overflow the facility and enter the receiving stream following treatment on site – a more environmentally friendly CSO.

The “deep tunnel” would be located about 170 feet underground close to the Missouri River.  Starting near the Gallop campus, it will end near the Missouri River Wastewater Treatment Plant, a length of about 5.8 miles.  At 12 ½ feet in diameter and lined with concrete or something similar, this will hold a lot of sewage.  But, if the capacity of this tunnel is exceeded, there would still be overflows.

And that’s important to acknowledge, CSOs won’t be eliminated.  With this plan, 4 overflow events per year would be allowed under the EPA/NDEQ permit.  Again, it’s a cost thing.  It is just too prohibitively expensive to do away with them altogether.  But it’s Omaha’s assertion that limiting them to 4 would achieve the water quality standards required.  And trust me, even at that level of control, it is still going to cost us and cost us big.

I’m hearing you say, “Us?  But I don’t live in the CSO area.”  (Or maybe you do, in which case, you anticipate getting clobbered.)  You don’t even have to live in Omaha.  Everyone who uses Omaha’s sewage treatment facilities will help pay for the solution.  And it’s not an MUD issue.  Omaha contracts with MUD to bill Omaha sewer customers.   So, if you pay a sewer fee to Omaha, whether or not through MUD, you’re in.  You are a user of the system and the system needs repairing, so everybody chips in.  That’s reasonable.  It’s not a problem for only those who live in the CSO area.  We all need to be concerned about the quality of our water and this will be a significant improvement.

I can hear you again.  “How much?”  The total cost is estimated to be in the neighborhood of $1.5 billion dollars.  $1,500,000,000.  And that estimate is in 2006 dollars and the project isn’t slated to be completed until 2024.  Think bigger.  Right now we have comparatively low sewer use fees for a community our size, so the only way to go is up.  Rates will climb steadily until we hit city projections of about $50 a month in the future.  Hopefully, it stops there.  (Programs will be in place, probably funded by users, to help people who can’t afford that kind of bill.)

The negative - this fix will be massively expensive, time consuming, and disruptive.  But on the plus side, it’s hard to argue with drastically reducing the dumping of untreated sewage into the Papio and Missouri Rivers.  And Omaha plans to use this huge construction project as an opportunity to coordinate replacing old water lines, streets, etc.  The CSO solutions are still being studied and refined.  Let’s be vigilant during this project to ensure that we get what we pay for.