A discharge which either inhibits or disrupts the POTW, its treatment processes, use or disposal; and is a cause of a violation of the POTW's TPDES permit, or of the prevention of sewage sludge disposal, is said to be

• A. Interfere
• B. Contaminate
• C. Obstruct
• D. Violate

Answer: (A)

Interference is the term for a discharge that inhibits or disrupts the POTW’s operation, its treatment processes, or sludge disposal, and that can cause a violation of the POTW’s permit. This definition fits exactly because it describes how the discharge harms the treatment works and can lead to permit violations or sludge disposal problems. Contaminate would mean simply introducing pollutants, not specifically harming the POTW’s operations; obstruct is similar in meaning but is not the formal regulatory term used here; and violate denotes the consequence rather than the characteristic of the discharge itself.