Which of the following is an accepted means for applying herbicides to control roots in wastewater collection?

• A. Aeration
• B. Foaming
• C. Stem injection
• D. All of the above

Answer: (B)

Foaming is used to apply herbicides inside sewer lines because the foam helps spread and cling to the root masses within the pipe, ensuring the chemical contacts the roots where they intrude the line. This method maximizes effectiveness while minimizing runoff and exposure elsewhere.

Aeration is a treatment process meant for oxygen transfer in the wastewater itself, not for delivering herbicides to roots in pipes. Stem injection targets above-ground plants by injecting herbicide into the stem, and is not a method used to treat roots inside wastewater collection systems. Therefore, foaming stands as the accepted means in this context.