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Fiber Optic Cable Installation in Sewers

December 22, 2011 - 3 Comments

By Steven Shepard, Contributing Columnist

Telecommunications infrastructure is so pervasive that we sometimes don’t even see it — one of those blind spots that fade from consciousness due to overexposure. Cables run from pole-to-pole; cell towers spring up; utility boxes on sidewalks, sometimes painted to match the wooden fence behind them — hidden within plain sight.

But there’s a lot of infrastructure that we don’t see — or if we do, we don’t pay attention to it. For example, many cell towers are festooned with warts that look like bass drums. These are microwave horns, and if you look in the direction they’re pointing, you’ll see another one, representing the other end of the circuit.

Orange conduit hanging on a pole is the universal signal that the conduit contains optical fiber. And, underground there is buried conduit (basically a dedicated pipe) through which thousands of route miles of copper, fiber and coaxial cable run, providing the communications nervous system for cities and towns.

There’s another piece of infrastructure down there that absolutely intrigues me.

Overcoming Right-of-Way Access Challenges

Telecom service providers frequently need to add connectivity infrastructure, but are faced with (1) completely full preexisting conduit or (2) the cost and complexity of getting permission to dig up a street in a city to add more conduit is prohibitive. What’s the alternative? Some carriers are looking elsewhere – in some cases, setting their sights on wastewater and sewage. Thus was born the Sewer Net concept.

The basic idea isn’t new. In fact, the oil industry has run telecommunications infrastructure through its pipelines for decades. The Oklahoma-based Williams Companies, which operates pipelines throughout the U.S. southwest region, were one of the first to enter the telecom space by running optical fiber through their pipeline infrastructure.

The company built two nationwide telecom networks; the first was sold in 1995 to LDDS, which became part of WorldCom and ultimately MCI, while the second became WilTel, later Level3 Communications.

Sewers have been used as ad hoc conduit now for years. Major cities in Japan (Tokyo), France (Paris), the UK (London, Birmingham), Australia (Sydney, Melbourne) and the United States (New York, San Francisco) all have high-speed optical transport running through their underground waste facilities. The UK alone has more than 360,000 miles of underground sewer conduit; it makes economic sense to take advantage of it.

Of course, there are the detractors.

While doing research for this story I found myself awash (no pun intended) in a whirlpool (no pun intended again) of questions/jokes about the Sewer Net technology, including issues of connectivity (USB on the side of the toilet — does flushing increase bandwidth?) and maintenance (as one fellow from India pointed out, pity the repair person that must access these pipes).

OK, enough. Do your own research. It is practical, but you have to admit it’s not the place that you might expect to find a solution to deploying fiber infrastructure, to meet the growing global demand for superfast broadband access to the internet.

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  1. I would use sewers if we had any but in rural areas we haven't. Any port in a storm is what I say, but we need to be getting fibre everywhere otherwise if we rely on the old copper phone networks much longer we will be left in the digital slow lane and become a third world country in the global village.

    • @cyberdoyle, point taken, the deployment challenges in rural areas leaves you with fewer options -- either dig and bury new cable or accept the limitations of wireless broadband infrastructure.

      • Here's yet another example from Taipei