Lower 48 Instruments specializes in partially filled pipe flow measurement, on site calibration and vacuum sampler integration.www.lower-48.com
The accuracy these meters provide for area velocity flow measurement is simply the best out there. Because the MACE sensors continuously see across the entire cross section of pipe instead of a pinpoint or a few points at a time, we can tune it to give our clients a true flow reading they can trust.
Chris Davis, Member, Lower 48 Instruments
By Helen Taylor
Infiltration Study Poses Challenges But Could Save Millions on Treatment Plant
Lower 48 Instruments works in partnership with consulting engineers to provide equipment and manpower for flow studies. IBI Group, out of Columbus, OH, USA, contracted with the company to provide placement expertise, equipment and data collection for a period of 60 days. Lower 48 installed 16 meters across the combined sewer district collection system to measure flow as well as rainfall-event intensity and duration.
In instances of clean water infiltration into sewer pipes, the source of the additional water can be tough to discern, especially in older systems that are large and susceptible to both stormwater and groundwater intrusion. This is the case in northeast Ohio, where a mix of residential and old commercial users bring in more than 5 million gallons a day for treatment across a 17-square-mile area, with more than 112 miles of collection line.
Lower 48 was hired to measure the source of infiltration and correlate the magnitude of increase with local rainfall. Affected municipalities will use the information to plan rehabilitation and repair projects and maintain EPA compliance. The application was familiar to Lower 48 Member Chris Davis, who has performed this kind of work many times before, but the complexity of this project and speed of installation (all meters had to be placed in two days) presented challenges.
Before the work could begin, site selection required coordination among several parties, which took nearly six months of communication. Once sites were identified, installation challenges quickly presented themselves. The crew dealt with stacked brick and stone manholes with no rungs, dating back to the 1930s; a natural gorge that required them to hand-carry metering from access points more than 3/4 of a mile away; and improper invert construction that necessitated minor demolition of concrete.
Power was another consideration. Davis would need to use a combination of solar panels in remote locations and batteries in city locations to provide power for up to 30 days at a time. One-minute scan intervals were eventually increased to five minutes, once final sites were determined.
“We needed that real-time access to data so we could react when a rain event occurred and not after the fact,” Davis says. “By initially speeding up data acquisition and transmittal, we could make better decisions as to final site location.”
Davis and his team deployed 16 area velocity sensors and rain gauges connected to In-Situ MACE FloPro XCi and HVFlo XCi monitoring systems, tied into In-Situ’s telemetry and HydroVu Data Services, in order to assist engineering support with data acquisition in near real time.
Davis uses In-Situ MACE meters in most of his installations because they’re reliable, accurate and have multi-power solutions including mains, solar or battery. He can easily collect both flow and rain data, and they afford rapid data acquisition for near real-time decision making. But accuracy is by far the main reason he chooses MACE first.
“The accuracy these meters provide for area velocity flow measurement is simply the best out there,” Davis says. “Because the MACE sensors continuously see across the entire cross section of pipe instead of a pinpoint or a few points at a time, we can tune it to give our clients a true flow reading they can trust.”
The data derived so far has enabled county personnel to locate a mile-long stretch of pipe in the collection system that is experiencing heavy infiltration due to damaged pipe obscured by grit collection. Davis says that while the final project is years away from completion, this installation is going to help save taxpayers tens of millions of dollars in construction costs for a new plant.