News and Opinion from Sisters, Oregon
News and Opinion from Sisters, Oregon
City councilors Tim Clasen and Lon Kellstrom learn about the sewer system from Paul Bertagna, the system operator.
Sisters' $13 million investment in wastewater treatment went on display for the city council on Thursday afternoon, July 26.
System operator Paul Bertangna explained the operation of the system that draws waste from Sisters south into acres of holding ponds, treats it and -- eventually -- sprays effluent on the forest floor.
The system is monitored and to a large degree operated by computer in a small cinderblock building that stands just outside the fence that surrounds the ponds.
Here, a sophisticated computer system samples the inflow and records that information. Later, the treated effluent will be sampled again and the two samples compared to determine how well the system is removing suspended solids.
"We're going to shoot for 95 percent removal," Bertagna said.
That's well above Department of Environmental Quality standards of 85 percent.
Currently, the amount of solids in the system is very high, Bertagna said, because there are not enough houses hooked up yet to dilute the flow.
Solids will settle to the bottom of the treatment ponds. Some of the sediment decomposes, and some accumulates. Sewer engineer Dick Nored estimates that it will be 20 to 30 years before the city needs to dredge out the ponds.
The center also contains the system's chlorination facility, which is a secure area where only trained and authorized personnel are allowed. The chlorine is "nasty stuff," Bertagna said, and is not to be trifled with.
The system shoots a measured amount of liquid chlorine -- twice the concentration of commercial bleach -- into a "flash mixer" that treats the effluent as it moves through pipes to the water cannons that will spray it on the forest.
That is the final stage of treatment, and it is likely that the system won't produce irrigation for two more years.
According to Bertagna, the longer the sewage is held in ponds, the better the quality of the effluent. Sisters is holding its sewage for a long time and is producing a very high quality effluent mostly by allowing nature to take its course.
The holding ponds are aerated by impellers -- essentially boat propellers -- that stir the mix and work in oxygen to break down solids. The effluent flows from one pond to another as it is treated.
The sewer water is extremely unhealthy and dangerous, Bertagna warned. The level of bacteria is so high that a person who is immersed in it is likely to suffer septic shock -- where bacteria attack and shut down the body's systems.
Exposure to the water could be fatal.
There is virtually no odor coming off the ponds, even when standing on the dikes. According to Bertagna, that's a very good sign for Sisters residents, because if the plant doesn't stink now -- with the highest concentration of solids it will experience -- it is unlikely to pose a problem when the full system is on line.
The system features weather gauges that monitor wind and temperature so that irrigation will be shut down if there's any concern that it might blow off the site.
A giant sieve perches on the dike by the first pond, where it separates out materials -- rags, for example -- that could tangle in the impellers or otherwise damage the system.
The Sisters sewer system is, according to Dick Nored, about as state-of-the-art as it can be and still remain affordable to the city. It is certainly the largest public works project the City of Sisters is likely to see.
Sewer system needs caution
By Jim Cornelius
Residents and business owners are enjoying a certain sense of freedom now that they don't have to fret over the condition of their septic systems.
However, according to wastewater system operator Paul Bertagna, they still need to be vigilant about what they put into the system.
Anything that's bad for a septic system is bad for the sewer system, too.
Grease is a villain. It builds up in pipes and can coagulate on the impellers that aerate the treatment ponds. Blocked pipes and broken impellers are expensive to fix -- and system users ultimately foot the bill.
Restaurants are required to install grease traps to keep the nasty stuff out of the system.
Other foodstuffs can be a problem, too.
"Egg shells, coffee grounds, they just don't break down," Bertagna said.
They should be thrown away, not washed down the drain.
And it's not just the city-wide system that could suffer from abuse. Individuals could find the pipes in their own homes and businesses clogged with grease -- and it'll be up to them to take care of the problem.
Jim Cornelius is editor in chief of The Nugget and author of “Warriors of the Wildlands: True Tales of the Frontier Partisans.” A history buff, he explores frontier history across three centuries and several continents on his podcast, The Frontier Partisans. For more information visit www.frontierpartisans.com.
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