Dirty Jobs: Inside Sewer Video SurveillanceBy Carlton Purvis, Published Feb 04, 2014, 12:00am EST
Analyzing images through sewage and murky water, cameras that regularly break with each repair costing thousands, running thousands of feet of cable. Such is the life of a pipeline camera operator. For another installment of our expert interview series, we spoke to a pipe inspection industry veteran about how CCTV is used to maintain aging infrastructure.
“The big push right now is to prevent overflows,” says Jim Aanderud, president of Innerline Engineering. An overflow, which often comes from a blockage in the line, can send thousands of gallons of sewage into storm drains and eventually out to rivers, and the ocean. The fines can be significant. Some places have been fined as much as $10 per gallon, he said.
Much of America’s pipelines were designed to have 50 year life-spans, but much of the existing infrastructure has been in place well above that.
“These cameras are the frontline of billions of dollars being allocated for the rehabilitation of sewer systems. Firms like mine are hired to do assessment of sometimes a whole city,” he said. “You’ll have a city with 1,000 to 2,000 miles of pipe. We’ll go in an inspect every foot of a city’s sewer line and try to identify all the problems that exist there. The city will decide what things they need to immediately rehabilitate or what can wait five or 10 years down the line.”
“The guts are mostly the same as what you’re using in surveillance cameras,” he said. Most are 720X480 resolution cameras, mounted on a robotic tractor tethered by a cable. The cameras are attached to an articulating head so they can look around inside a pipe and zoom in to inspect anomalies. Other setups use panoramic cameras.
The photos below are what these cameras typically look like. The photos are from Aries Industries, Envirosight and CUES, respectively.
Here's the view from a camera:
The light sources for modern pipe inspection cameras come from LEDs, which he said is a big improvement over lights used in the past. Aanderud, who has been in the pipe inspection industry for more than 20 years, says old light sources were so hot, operators could get burned from touching them and in an underground sewer environment, they would cause foggy images. The LEDs do a better job of illuminating the pipes. Cameras now also have both automatic and manual iris control to give operators more control over the amount of light to get optimum images.
Pipe cameras don’t use HD.
“The simple reason for that is because of storage issues,” he said. These inspections produce a large amount of data. "We finished a city recently where we did over 2.4 million feet of inspections and ended up with 10,000 different data files, and over 4,000 videos, pictures and reports.”
"Even though storage is getting larger and cheaper, the transfer of the files become excessive. Also, it is my understanding that the cables being used aren't capable of pushing the HD signal and new fiber optic cables may be needed. When you are talking 2,000 to 3,000 foot cables the cost is significant," he said.
On a daily basis operators are collecting 2,000-4,000 feet of inspections. All of this is being sent over cables back to a truck above ground where the images and video are processed and stored. This data is stored on Innerline Engineering hard drives indefinitely, and drives are provided to the cities. Some cities upload the data to their GIS systems.
Why Wireless Isn’t an Option
Aanderud says the closest this field has come to wireless is internal storage. The cables used are 1,000-3,000 feet long.
“You have a limitation on distance, but most manholes are designed to be 250 feet apart so our inspections are usually manhole to manhole,” he said.
The “crawlers,” as he called them, crawl down the lines looking for built up grease, roots breaking through pipes, broken pipes and blockage.
“We have a project right now where I have to send individuals into a sewer line 400-600 feet down. I’ve been trying to get wired communication, but every one does wireless now. Wireless just isn’t able to penetrate the ground and transmit around corners,” he said.
One company makes cameras that can record and store images from one manhole to the next internally, but then it has to be brought back so the data can be retrieved.
Pipe Cameras Have a Rough Life
Because of the extreme operating conditions, the cameras tend to have a pretty rough life. A camera typically lasts about five years, but in the period of time “you’re spending tens of thousands” of dollars on repair costs. Small repairs are done in-house, but major repairs usually require cameras go back to the manufacturer. The average repair costs $5,000.
“It’s not something you put in place and then you leave. When we buy something we’re entering into an ongoing relationship with that manufacturer,” he said.
Aanderud uses Kevlar reinforced cables, which add significant weight being dragged behind a camera, increasing wear on equipment.
The cameras don’t typically just die after five years, however. It’s a gradual decline.
“The cameras often deteriorate very slowly so you could be using a camera that is taking terrible pictures, but not notice because it happened so slowly,” he said.
Aanderud, who has written articles about training operators [link no longer available], says the best operators have a strong computer background and a good mechanical ability, “because there is always something breaking, and you need to be able to fix the problems.” He said he also looks for people who are detail oriented and organized because they are not only inspecting these pipes for cracks, but also dealing with large amounts of data. An organization, NASSCO, [link no longer available] provides a three-day training course and manufacturers will also provide a few days of training with the purchase of equipment he said.
“What we try to do with guys,” he said of his company “is expose them to it for a year before they start operating.” They work on the truck providing support to the team or helping with traffic control and maintenance, eventually moving up to become an operator after they understand how the whole operation works.
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