Huntsville Undertakes Nation’s Largest Root Control Project

By Jeff Griffin, Senior Editor | January 2009 Vol. 64 No. 1

The city of Huntsville, AL recently completed one of the largest sanitary sewer chemical root control projects in the country.

Over a one year period, 1.6 million linear feet of sewer pipes ranging in size from 6 to 24 inches in diameter were treated with Category E non carcinogenic herbicide. Huntsville's sewer system is operated by the city's Water Pollution Control Department (WPC). Duke's Root Control Inc. performed the work.

Huntsville, AL, is one of the nation's fastest growing cities and is an interesting combination of high tech industry and old South charm. With a population of more than 170,000 and growing, Huntsville residents find the city's size is "just right" – big enough to attract diverse businesses and be the home of NASA's Marshall Space Flight Center and Redstone Arsenal, but without the urban sprawl and traffic of large metropolitan areas.

Huntsville's wastewater collection system is composed of more than 1,300 miles of underground pipes ranging from six to 78 inches in diameter, 33,000 manholes and 57 pumping stations. Wastewater is treated in six treatment plants. Keeping the collection system running smoothly is a full time, year round job.

Huntsville is a beautiful city and those who live there are proud of its progressive attitude along with its rich history which is carefully preserved. Stately trees line the streets of the Twickenham historic district which contains Alabama's largest collection of homes constructed before the Civil War. Huntsville takes great effort to protect trees throughout the city, and each year is designated a Tree City USA Community by the National Arbor Day Foundation.

However, the roots of those trees have posed a continuing problem to Huntsville's sanitary sewer system, a situation often shared by other cities.

Lots of trees, lots of roots

Roots enter sewer pipes as tiny, hair like structures which grow quickly. Roots thrive inside sewer pipes because the pipes provide a perfect environment for growth: a well ventilated area with a steady supply of water containing high levels of nutrients, continually replenished by fertilizer in temperatures that remain relatively constant.

Roots not only restrict flow, but separate and crack pipe joints. Often sewer system owners are not aware of root problems until a major blockage occurs, and when roots are removed, inspection reveals major damage to pipes.

The U.S. Environmental Protection Agency (EPA) identifies root intrusion as the single most destructive problem of maintaining wastewater piping systems.