sewers Archives - Infrastructure Digest

There’s gold in them thar sewers—tons and tons of it!

The study’s lead environmental engineer, Paul Westerhoff, told Science that the sewage treatment systems that collect and try to dispose of the waste could be losing a lot of  precious cargo in the process, citing a city in Japan that collected near 2 kg of gold in every metric ton of ash after burning sludge.

Why should you read this? That’s a lot of gold. Quartz, January 2015

Using Grout to Stop I/I

The Village of Ashley project resulted in the Central Ohio Wastewater Services crews in finding significant I/I at the manholes. Crews found 17 manholes next to a creek in the woods that were 16 to 26 ft deep with a very high water table. In looking into the cost for replacement for all the manholes, the cost totaled approximately $300,000.

“The Village of Ashley did a (cured-in-place pipe) CIPP liner project in 2007, removing half the peak flow from 1 million gal/day to 500,000 gal/day at a plant that was designed for 190,000 gal/day,” Howard explains. “We found the infiltration was coming between the CIPP liner and the original pipe releasing at the manholes. The acting engineer at the time had heard of Source One Environmental (S1E) LLC and its product so we gave it a try. Since the start of the project, our average dry time flows have went from 60,000 gal/day to 30,000 gal/day and heavy rain fall events have fallen from 500,000 gal/day to 250,000 gal/day making the plant more efficient.”

Why should you read this? The effectiveness and precise role of chemical grouting is too little understood by sewer network managers, IMNSHO. Trenchless Technology, November 2014

Sewer Jetter Winterization

If the distance between two jobs is short (10 min or so), some jetter owners opt to keep their unit on with the water recirculating, rather than re-winterizing. However, this is not recommended when temperatures are extremely cold (subzero), or if the travel time between jobs is too long.
Please note that jetters should be winterized with “pink” or “RV” antifreeze only, not the “green” antifreeze most often used in automobiles. Besides being more environmentally friendly, pink/RV antifreeze is far less caustic and won’t cause premature wear on your jetter’s inner workings. As for the antifreeze-to-water ratio, a popular saying is that “50/50 will get you 50 below.”

Why should you read this? It’s Winter! This is news you need. Trenchless Technology, December 2014

City of Columbus, Ohio, Designs ‘Blueprint’ to Control Overflows

However, as the City began to enter subsequent phases of the tunnel program that focuses on controlling separate sanitary overflows, it decided to take a different tack. Rather than continue to build out the tunnel program, the City decided to address the cause of the overflows rather than the symptoms by refocusing its efforts on eliminating inflow-and-infiltration (I/I) through a comprehensive rehabilitation program and green infrastructure improvements. City officials believe that this approach — dubbed Blueprint Columbus — will achieve greater water quality benefits in a manner that will offer economic and social advantages that will benefit the City for generations to come.  

Why should you read this? Everyone loves a good I&I reduction story… Trenchless Technology, November 2014

Who’s clogging Seattle sewers with concrete?

Seattle has a public works mystery. In less than a month, two different sewer lines were found to be blocked by concrete, causing at least $350,000 in repairs, according to multiple reports.

The first incident occurred on Fairview Avenue North, clogging 70 feet of the pipe, reported KIRO 7.

“We don’t know who did it. We’re fairly certain we’ll find out who did it because that amount of concrete is probably coming from a construction site nearby,” Cornell Amaya, with Seattle Public Utilities told the station.

Why should you read this? Is it vandalism, terrorism, stupidity… or all three at once? Seattle will be analyzing the concrete to find the origin. Public Works, November 2014

KS Associates Takes 3D Laser Scanner Underground to Help NEORSD Abate Combined Sewer Overflows to Lake Erie

The goal of this project was to replace a fatigued inflatable dam in the 96-inch sewer that collects combined sewer flow from northwest Cleveland. The inflatable dam is an important mechanism that stores upstream combined sewer flow, reducing CSO discharges in the collection system before the flow is transported to a nearby wastewater treatment plant. NEORSD decided to remove the inflatable dam and replace it with a more efficient hydraulic sluice gate. The District hired URS Corporation to perform design services.

Laser scanning offered several benefits over conventional surveying methods. According to Mark A. Yeager, P.S., KS Associates Director of Surveying Services, “For safety reasons, surveyors could only enter the sewer during dry weather flows. Once we had our window of opportunity, accessing an active sewer five stories below ground posed safety challenges and required specialized confined-space procedures. Our priority was to measure the entire junction chamber and obtain the geometry that URS needed in as little time as possible. Using 3D laser scanning, we successfully gathered all the data and more — in one trip. Manually obtaining these details would have required more time at the project site and would have been more physically challenging.”

Why should you read this? As laser scanning becomes less ‘gee-whiz’ and more ‘ho-hum’, more and more uses are becoming obvious. Might your sewer network benefit from some scanning? Informed Infrastructure, September 2014

What the Heck is Acoustic Pipe Inspection?

“Simply put, acoustic pipe inspection, or AI, uses sound to locate and characterize pipe based on the sound of flowing water. And, it’s quickly becoming a buzzword for infrastructure owners and managers thanks to its potential cost savings.

AI systems can help prioritize maintenance needs, which lets utilities avoid needless cleaning of relatively clean pipes or repairs to pipes with only minor issues.”

Why should you read this? Cheap, effective pipe inspection and leak detection? Sounds interesting (see what I did there?). First of three articles. Municipal Sewer & Water, December 2014

Ebola Information Released for Water and Wastewater Utilities

“Because of Ebola’s fragility when separated from its host, bodily fluids flushed by an infected person would not contaminate the water supply. Researchers believe Ebola survives in water for only a matter of minutes. This is because water does not provide the same environment as our bodily fluids, which have higher salt concentrations. Once in water, the host cell will take in water in an attempt to equalize the osmotic pressure, causing the cells to swell and burst, thus killing the virus.”

Why should you read this? You don’t really need to—I’m just jumping on the Ebola news bandwagon. Basically, there is no Ebola danger to treatment plant workers, but this article can be reassuring. Treatment Plant Operator, October 2014

Innovation And Proactivity Put The City Of Evanston Ahead Of The Storm

“Evanston, Ill., has launched a three-pronged attack on stormwater overflows, but the increasing frequency and intensity of rain events is making the task more challenging.

Plagued for years with flooded basements and customer complaints, the utility has built a new system of stormwater relief sewers, added several new storm sewers, and installed flow restrictors which prevent storm drain overloads by forcing stormwater to pass down the street or alleyway to larger drains.

And while the system works well, Utilities Director Dave Stoneback says the heavier rainfalls the city has experienced in recent years can still cause flooding problems, especially in winter.”

Why should you read this? If you manage sewer networks, it’s always nice to learn how others are doing it. Municipal Sewer & Water, December 2014

Technology and Its Impact on Reducing Inflow and Infiltration

“Fixing I&I defects in collection systems with multiple I&I sources can be complicated. With the advancement in sewer line rehabilitation, removing the I&I is more affordable than in the past. Further, if you add in the potential costs of I&I to the environment and to the impact on a community’s growth and quality of life, I&I reduction is a high value, necessary investment.

The EPA estimates that if the nation’s infrastructure needs are not addressed in the next 10 years, 35 years of water quality gains will be lost. Even though removing I&I can be a net cost-saver, the work required to remove it from a sewer system isn’t cheap. Municipalities need to be strategic in designing their I&I remediation efforts and do whatever they can to minimize the cost impact of the program on ratepayers and taxpayers. Today’s technologies are playing a large part in closing this gap, and we can all expect the coming years to produce even greater technologies to address our infrastructure needs.”

Why should you read this? Useful overview of current technologies that help to prioritize and maximize I&I reduction investments. Trenchless Technology, November 2012

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