Sewer Line Pest Control

Q. When may tree roots be considered a pest?
A. Tree roots become pests when they affect humans' property and well being, especially when they invade and damage sewer pipes in search of food and water.

Q. Name several different types of pests.
A. Some insects, other invertebrate organisms such as spiders and ticks, plant diseases, weeds, and vertebrates such as mice and rats.

Q. What is a pesticide?
A. A pesticide is any substance or mixture of substances intended to prevent, destroy, repel or mitigate any pest, or for use as a plant regulator, defoliant or dessicant.

Q. Distinguish between a General Use Pesticide and Restricted Use Pesticide.
A. A restricted use pesticide has more potential for harming humans and the environment than a general use pesticide and may only be applied by or under the direct supervision of a certified applicator.

Q. An applicator that applies or supervises the application of a restricted use pesticide in any area for a fee is called:
A. a commercial applicator.

Q. Name the two types of root systems associated with sewer problems.
A. Fibrous root systems and tap root systems.

Q. Name at least three factors around sewer pipes that influence root growth.
A. Backfill soil around the pipe is more attractive than compacted soil , roots are hydrotropic and seek moisture, a dropping water table attract roots deeper, warmer temperatures around the pipe are more attractive than colder surface temperatures.

Q. Describe the two types of root structures found in sewer lines.
A. Veil root structures hang from pipe with steady flows, and sweep the tops of the flow or nutrient. Tail root structures grow in pipe with low or intermittent flow and look like horses' tails growing downstream.

Q. Name at least three different non-chemical root control methods.
A. Cultural control, physical control and mechanical control.

Q. Name at least three chemical control methods other than metam-sodium.
A. Use of herbicides, acid or basic compounds, copper products and trifluralin impregnated fabric.

Q. Explain differences between contact and systemic herbicides and between selective and nonselective herbicides.
A. Contact herbicides quickly kill only that part of the plant they contact, whereas systemic herbicides are slowly transported throughout the plant and kill it. Selective herbicides will affect one type of plant, such as broadleafs or grasses, whereas non-selective herbicides affect all types of plants.

Q. Name several methods used to identify which lines have root problems.
A. Maintenance histories (scattergrams), sewer line television reports, and commonalities in root prone areas.

Q. What is a pesticide formulation?
A. A formulation is a mixture of active ingredients (control material) and inert ingredients (carriers and other agents such as foam).

Q. Describe the formulations used with metam-sodium root control products.
A. Metam-sodium is a liquid formulation that includes a foaming agent or requires a foaming agent to be added prior to dispersal. Dichlobenil is a wettable powder that may be added to the metam-sodium foam mixture.

Q. Describe what happens to metam-sodium in the presence of water.
A. Metam-sodium mixed with water will hydrolyze to form MITC, H₂S, CS₂ and other minor products.

Q. How can hydrolysis of metam-sodium affect an applicator?
A. MITC, a product of hydrolysis, is a highly toxic gas.

Q. Why is dichlobenil added to metam-sodium as a root control pesticide?
A. Metam-sodium is a contact herbicide, killing only those root parts it contacts. Dichlobenil is a residual type herbicide that continues to control root growth for a period after application.

Q. Explain the difference between the terms "Label" and "Labeling".
A. The label is information printed on or attached to the pesticide container. Labeling includes the label and all other information received from the manufacturer about the product.

Q. Explain the differences between brand, chemical and common names.
A. A brand name is usually a trademark used by manufacturers to identify their product. The chemical name is a complex name that identifies the chemical components and structure of a pesticide. A common name is a shorter name that the EPA recognizes as a substitute for the chemical name.

Q. Name and explain the signal words and symbols you may see on a pesticide label.
A. "Caution" indicates the product is slightly toxic or relatively nontoxic. "Warning" indicates the product is moderately toxic. "Danger" indicates the pesticide is highly toxic and may be a skin and eye irritant. The addition of "Poison" in red and the skull and crossbones indicates the pesticide is highly toxic as a poison.

Q. What types of hazard statements should you look for on the label?
A. Look for precautions about hazards to human (and domestic animals), environmental hazards, and physical/chemical hazards.

Q. Describe how a metam-sodium and dichlobenil root control product is packaged and labeled.
A. Each product is packaged and labeled separately. The overall label will list all ingredients in the complete package. The label has a statement "Only for use as a combination of metam-sodium, dichlobenil and foaming agent as directed".

Q. What are the three components of handling wastewater?
A. The three components are collection, treatment and disposal.

Q. What is the difference between a sanitary sewer and storm sewer?
A. A sanitary sewer collects waste from buildings and transports it to a treatment plant before emptying into a watercourse. A storm sewer collects surface runoff water and transports it directly to a watercourse.

Q. Name several variables in a wastewater collection system that will influence root control operations.
A. Root control operations may be affected by the pipe slope/grade, the flow, characteristics of the collection system, aging of the wastewater and generation of gases.

Q. Describe the series of treatment processes removing waste from water.
A. Pretreatment/preliminary removes coarse material from the wastewater. Primary process involves settling out or floating solid matter for removal Secondary treatment consists of biological processes converting missed solids into more easily removable material.

Q. What is the purpose of waste treatment ponds (lagoons)?
A. To treat wastes remaining after the other processes. Flow through time is 4-60 days, depending upon design.

Q. What is the difference between design flow and actual flow?
A. Design flow is the amount of flow a system is designed to handle daily. The actual flow is the amount of flow actually passed through a system daily.

Q. How can metam-sodium seriously affect the operation of a treatment plant?
A. If a plant is under stress, the addition of even a small amount of metam-sodium could upset the biological processes and last from hours to days.

Q. What is the applicator's main concern when treating building service lateral lines?
A. Forcing foam root control pesticide through lateral lines into buildings.

Q. How may pesticide enter your body?
A. Orally, dermally, by inhalation and through the eyes.

Q. Name the three ways pesticides can cause harmful effects.
A. Acute effects, delayed effects, and allergic effects.

Q. If pesticide is splashed into the eyes, what should you do?
A. Immediately flush the eyes with large amounts of water for at least 15 minutes. Hold the eye lids apart to ensure adequate rinsing of the entire eye. Seek medical assistance.

Q. Why is it necessary to wear PPE?
A. PPE is the best way of protecting your body from exposure to a pesticide.

Q. If you must work in a tight area treated with metam sodium, where considerable gas is evolving, what is the best respiratory protection to wear?
A. Wear either an air supplying respirator or a self contained breathing apparatus.

Q. What is a closed handling system?
A. A closed system allows the applicator/handler to remove a pesticide from its original container, rinse the empty container, and transfer the pesticide and rinse solution to a mix tank without contacting the pesticide.

Q. What are good features to have in a pesticide storage room?
A. The storage room should be cool, dry, well ventilated, well lighted and in a secured building that is insulated to prevent freezing or overheating.

Q. What are the major steps for handling a pesticide spill?
A.

• Control the spill to prevent spilling more pesticide.
• Confine the spill to keep it from spreading.
• Clean up the spill by placing it in labeled containers and disposing of the material in an approved manner.

Q. Briefly describe two types of foaming equipment.
A.

1. Utilizes a 30-300 gallon mix tank in which chemical and water are mixed. The solution is delivered under pressure to a foam production chamber, then pumped out as a chemical-foam.
2. Utilizes a small (3-6 gallon) tank into which only chemical is added. The chemical is pumped under pressure to a venturi, where it is introduced into the water stream and into a foam chamber. Foam is then pumped out as in (1) above.

Q. Name the foaming techniques used for applying metam-sodium root control chemicals.
A.

• Hose insertion method
• Split hose insertion method
• Hose insertion: "Pushing a slug"
• Hose insertion: "Pulling the water out"
• Hose insertion: "Treating wye connections"
• Surface coating large diameter pipe
• Spot treatments
• Pushing foam through inflatable plugs

Q. When filling a mix tank, how can you prevent back-siphoning?
A.

• By using an air gap between hose and tank
• By using a back flow preventer or double check valve
• By using an intermediate water source, such as a jetter

Q. How can an applicator calculate the amount of chemical required for a specific job?
A. Determine if the foam fill or foam spray method will be used. Select the appropriate chart for that method, then refer to the product's label to determine the amount of water to mix with 1-part of chemical. This total will be used in the "dilution ratio required " column to complete the calculation.

Q. Why is it necessary for the certified applicator to communicate with treatment plant personnel?
A. First to alert personnel that a chemical will be introduced into their system, so they may monitor for signs of upset and any unusual side effects from the chemical. Also, it may be necessary to obtain a discharge permit for the pretreatment program . Second, the applicator should obtain information about times of high flow, sizes of pipe to be treated, and distance of the sewer line from different sewer structures such as the nearest lift station and the sewage treatment plant.

Q. How do you calibrate the hose retrieval rate?
A. Determine the gallons of foam required per foot of sewer pipe. Next, determine the gallons per minute that the application equipment produces. Then determine hose retrieval in feet per minute by dividing the amount of foam produced per minute by the foam required per foot. A chart is also available to assist the applicator.

Q. How can the applicator determine the effectiveness of root control treatments?
A. This is not easy. Several methods must be used, including viewing the root masses in the lines through closed circuit television, pulling treated root masses and inspecting them for live tissue, and comparing the rate of sewer stoppages in a given area before and after treatment.