Technology

Running Fiber Through the Sewers

Sewer-based fiber to the home networks may be a cost-effective way to provide superfast Internet connections. Quincy, Ill. is pursuing this option slowly.
by | September 21, 2010

This week, two streets in the river town of Quincy, Ill., will become different than all others -- under the surface, that is. The town is testing the option to run a superfast fiber to the home (FTTH) network in an unusual way -- through the wastewater system.

Before committing to full-blown FTTH via the sewer, the 16-square-mile city of 17,000 homes is using this pilot to test whether deployment in this fashion is the right approach, as was announced in mid-September. Fiber-optic cable will be installed in 1,300 feet of sewer on Harrison and S. 46th streets beginning Sept. 21 and concluding Sept. 24. Then the cable will rest there, untouched by the city for 30 days. On October 24, the city will begin evaluating the cables to determine whether this method is a fit for Quincy.This will be the first sewer deployment in the U.S. for i3 America, part of i3 Group Ltd., which has deployed multiple FTTH networks through wastewater systems in the United Kingdom and Australia. The deployment comes at no cost to Quincy.

"We decided, after all the due diligence was done with our legal folks and my council, that we would allow them [i3 Group] to come in and test a part of what they do," says Quincy Mayor John Spring. "We're looking forward to it. We're not sure what we'll find out, but they're pretty confident that if it's working in the older part of the world, it should work in the newer part of the world."

Fiber to the Home History

Many current U.S. FTTH networks (in about 85 cities) deployed fiber underground via trenching or other alternatives. Trenching involves digging a three-foot channel in the public right-of-way, which is not only costly, but also highly disruptive. Then there's alternatives like microtrenching, which while still in the public right-of-way, requires a smaller duct --  about half an inch wide and less than a foot deep. This method is still disruptive, though less so, and is estimated to cost less than half the cost of traditional trenching, according to OSP Magazine.

On the whole, 16 percent of North American households have FTTH broadband connections, compared to 34 percent in Japan, according to the Fiber to the Home Council. Many of these international locales that offer FTTH -- like Tokyo, Paris and Vienna, to name a few -- are using the sewer approach, which saves money. The reason for that is simple: The wastewater system already exists, so there are no costs to run separate lines for fiber-optic cables.

"From where we have all our active equipment, we actually run out using the sewer system -- or any other existing conduits that are available -- to take that fiber into the immediate neighborhood area," says Alasdair Rettie, technical director at the i3 Group. "And then we'll use traditional or other methods we've devised to actually connect to the homes. We've achieved a solution that reduces cost by 30 to 50 percent."

Laying Cable in the Sewer

Though Rettie says i3's solution has been successful in the U.K. and Australia for the past eight years, there are some concerns about whether it will work for Quincy. One of the concerns is that last year, the city had approximately 52 breaks in both its water and sewer systems, Spring says. A break that occurred a few weeks ago closed a heavily-traveled street for about four days. The city had to make the necessary repairs, place the underlayment and concrete overlayment, and then let it substantially dry before allowing heavy traffic back on the roadway.

So what happens if FTTH is set up through the sewers and one of those sewer lines collapses, breaking a fiber-optic cable? Luckily, that recent sewer line break, Spring says, didn't disrupt someone's phone service, cable TV or Internet service. But had fiber-optic cable been installed, the sewer break could have caused more havoc.

"What'll happen is, if a street's closed off, that's OK with people," Spring says. "But if all of a sudden, they can't get their cable TV or can't get on the Internet with this high-speed fiber optic that the mayor has now presented them? ... Do you see where I'm getting [at]?"

In addition, weather concerns also could derail the potential of a sewer-based FTTH deployment. "We're in a climate here where we have a lot of hot and cold variations during certain times of the year. It can be 15 degrees below zero here one day, and the next day it could be 55 to 60 degrees above," Spring says. "And with any component that's in the ground, whether water or sewer lines, the stress put upon them with the temperature change and the earth moving -- along with the heavily-traveled streets -- it can cause problems."

But i3's Rettie says the pilot will be successful. "Damage to the sewer network can happen," he says, noting that i3 installs video cameras so it can see issues as they occur. Rettie also says the i3 method is different than how other companies or municipalities deploy fiber in the sewers. Other installations traditionally tack the fiber along the top of the sewer with stainless steel bands, he says. "If those stainless steel bands become dislodged or damaged or corrode, that fiber will drop down in the sewer," Rettie says, "and that has the potential to cause a blockage." The blockage is less a problem for the fiber-optic cable as it is for the sewer; because the fiber is hanging from above, Rettie says debris can get caught.

The i3 Group's solution deploys the fiber along the bottom of the sewer so it lies flat. In addition, the fiber is attached to the sewer at each manhole point using patented manifolds or mats and a special epoxy adhesive. "As you can imagine, a sewer is very dirty and wet, and not very hospitable," Rettie says, "but the epoxy has been used within the oil industry, and it can actually set and adhere in the sewer environment."

Overall, Quincy is looking forward to this pilot and the potential it holds. Spring says he has city engineers and outside consultants working on the project, as well as people with fiber optic experience. "We've got a great team assembled; we're excited about this and hope it can become a reality for our community," he says. "I think overall it's going to be a real positive thing, but we've got to get this pilot program started and take a look before we make any final decisions."

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