Scott Township’s Director of Public Services, Tom Kelley, would like to share information with all of our residents about root control efforts in Scott Township:
Facts about Root Control in Sewers
Scott Township is planning to implement a program to improve our aging sewer system by applying an aquatic herbicide approved by the US Environmental Protection Agency and the Pennsylvania Department of Agriculture for the specific purpose of controlling root damage. Sewers with chronic problems will be treated on a rotating basis as indicated by a database that lists sewers that have recently exhibited root problems. Here are answers to common questions concerning the use of aquatic herbicides to clear tree roots from sewers.
Why do roots in sewers pose problems?
Roots thrive in sewers because sewers provide the perfect environment for growth: good ventilation with a steady supply of water containing high levels of plant nutrients in temperatures that remain relatively constant. Many of our aging terra cotta pipes have cracks and have been invaded by tree roots. When roots block the flow or a sewer, sewage backs up into basements and poses health hazards. Many of sewer backups in Scott Township are caused by roots.
Are certain sewers susceptible to root invasion?
Sewers likely to have root problems include: sewers near other sewers with root problems; sewers located near the surface and near trees; sewers in wooded easements or at curb lines near trees and roots; sewers with many lateral connections per lineal foot, affording greater opportunity for root invasion; sewers on tree-lined streets and easements; sewers in residential areas, and sewers constructed with loose-fitting joints or outdated joint packing materials. Scott Township has these conditions.
Why treat sewer blockages with aquatic herbicides?
For years, Scott Township’s public works department flushed roots out of sewer pipes by using a high-pressure water pump. If there is a crack or a hole in the pipe, however, high pressure will aggravate and possibly collapse the pipe. Also, mechanical treatment of blockages in large lines requires heavy, expensive equipment and cannot reach roots penetrating through joints—and the cutting process actually encourages newer, thicker growth. The herbicide prevents roots from growing back for three years—10 times longer than the old high-pressure flushing system. Mechanical root treatment is still in use, but chemical root control is becoming more standard because it is less labor intensive and longer lasting.
Will the same sewers treated each year?
Sewers that have been treated should remain in good working order for up to three years (and a warranty with the contractor ensures that they will be retreated at no charge, if necessary, within that time frame.) The program will be set up to treat sewer lines on a rotating basis. A few chronic areas may need to be treated every year or every other year; previously treated lines that have been rehabilitated by lining or point repair as a result of the consent order are removed from the rotation, and new problem areas will be added as appropriate.
What are aquatic herbicides?
Aquatic herbicides are chemicals that control root blockages in sewers. They also are used to control vegetation in farm ponds and lakes, as well as for agricultural applications and to inhibit invasive plants. There are several kids of aquatic herbicides. Scott Township’s contractor uses a contact herbicide, which kills only the growth it comes in contact with and does not travel through the plant system.
How are aquatic herbicides applied?
Foam containing the herbicide is pumped into a manhole at low pressure through a discharge hose. The foam is compressed against all pipe surfaces into cracks and joints and is forced a short distance up the lateral sewers for maximum contact with roots. It cannot enter your house. The application destroys only roots it comes in direct contact with; it does not harm trees. The dead roots decay and slough off. Sewer service is not interrupted.
Who applies the aquatic herbicide?
The firm that is awarded the contract will be a well-respected national company with a solid record of performing this sort of work in multiple municipalities.
Are aquatic herbicides safe for people, pets and plants?
Two quarts of aquatic herbicide are mixed with 100 gallons of water, which then produces 2,000 gallons of foam. The resulting concentration of herbicide in the foam is far below the Environmental Protection Agency’s contaminant level for drinking water. In addition to the contractor’s normal precautions, Scott Township will implement the following safety precautions: The material will be mixed at the public works building, not on-site, using a closed mixing system; a Scott Township public works employee will be on hand at all times to oversee the application, making sure that the chemical never comes in contact with anything other than the inside or the sewer; When the crews retrieve the hose from the manhole, some liquid—mostly sewage—may spill. If this happens, the spilled material will be collected on the spot and returned to the sewer; the spot will be sanitized, and the incident is recorded.
Treatment probably will not begin until this fall. Before treatment begins, residents in the immediate areas will be notified by fliers.