The U.S. Environmental Protection Agency (EPA) currently is
developing an audit program that will evaluate compliance of all aspects of
collection system Capacity, Management, Operation and Maintenance (CMOM). So,
maintaining full pipeline capacity and avoiding sewer backups and overflows are
more important than ever. Effective root control, which minimizes hazards to
humans, the environment and treatment plants, can be a critical element in
maintenance planning for sewer lines.
Root control always has been a challenge for municipal sewer
agencies. Some municipalities cut the roots out when they are found, but too
often the problem is not found until a blockage and perhaps an overflow has
occurred. Cutting the roots is a short-term solution and possibly can compound
the problem. Roots respond to cutting the same way a hedge does; each cut
produces a half-dozen new sprouts. Within three months, the roots usually are
much thicker than before the cutting.
Chemicals have been used to kill roots since the mid-1970s.
Until recent years, chemicals could produce negative impacts on people,
treatment plants and the surrounding environment. Now there is a new generation
of root control chemicals that does not produce negative impacts on the
treatment plant or the people who use it yet still effectively eliminates
troublesome root problems. The simplicity and effectiveness of this new
generation of root control allows any applicator, whether it be a municipal
sewer agency or contractor, to become a root control professional—even
with minimal experience.
The new generation of chemical root control utilizes
Dichiobenil, an aquatic herbicide, as its active ingredient with a label
designation of "warning" as opposed to "dangerous." This
new generation of chemical root control also is classified as a general use
herbicide by the EPA, which means licensing may not be required for
application. The formulation also contains surfactants to strip away grease and
grime so the active ingredient more easily can reach the surface of the root.
The rest of the formulation encourages bacterial growth to speed the natural
decomposition of the dead roots.
Appling to Mainline Sewer
The new generation of chemical root control is able to foam
on contact with water. This means the application process can be done directly
from the package or with existing sewer cleaning equipment. The foaming action
carries the active ingredient to the top of the pipe where 90 percent of root
growth occurs. The foaming action also leaves a residual on the roots and pipe
walls to eliminate new growth for a period of time. By pouring the dry powdered
product directly into the manhole or cleanout, the product will foam by adding
water or coming in contact with the existing flow. The foam will expand and
move down pipe with the flow, leaving a residual on the roots and pipe walls.
The product also may be applied with existing sewer cleaning
equipment by using a foam dispersal unit, which is a nozzle that fits onto the
end of a jetter hose. Starting at the upstream manhole, the applicator fills
the nozzle with the dry powdered product and attaches the nozzle to the jetter
hose. As the jetter operator retrieves the hose, he turns the jetter on idle to
add water into the nozzle that disperses the foam spray throughout the pipe,
coating the roots with the root-killing formula. This also adds value to the
jetter unit by being able to use the jetter as a root control machine while in
the field doing other maintenance projects such as cleaning.
A regular maintenance program with chemical root control can
help municipalities meet the local, state, regional and national regulations
that are set up to avoid sewage overflows. CMOM is an example of those
regulations. Utilizing applied chemistry such as the new generation of chemical
root control will allow municipalities and contractors to meet these challenges
cost-effectively, while being a valuable tool in complying with these