(A) The following described substances, materials, waters or wastes shall be limited in discharges to the municipal sewer system to concentrations or quantities which will not harm either the sewer mains, the sludge of any municipal system, the wastewater treatment process or equipment, will not have an adverse effect on the receiving stream, or will not otherwise endanger lives, limb, public property or constitute a nuisance. The Public Works Director may set limitations lower than the limitations established in the regulations below if, in their opinion, such more severe limitations are necessary to meet the above objectives. In forming their opinion as to the acceptability, the Public Works Director will give consideration to such factors as the quantity of subject waste in relation to flows and velocities in the sewer mains, materials of construction of the sewer mains, the wastewater treatment process employed, capacity of the wastewater treatment plant, and other pertinent factors.
(B) The limitations or restrictions on materials or characteristics of waste or wastewaters discharged to the sanitary sewer which shall not be violated without approval of the Public Works Director are as follows:
(1) Wastewater having a temperature higher than 150ºF (65ºC);
(2) Wastewater containing more than 25 milligrams per liter of petroleum oil, no biodegradable cutting oils or products of mineral oil origin;
(3) Wastewater from industrial plants containing floatable oils, fats or grease;
(4) Any garbage that has not been properly shredded (see § 4.01.010). Garbage grinders may be connected to sanitary sewers from homes, hotels, institutions, restaurants, hospitals, catering establishments or similar places where garbage originates from the preparation of food in kitchens for the purpose of consumption on the premises or when served by caterers. The wastes that enter the sewer in this manner are to be from food preparation operations only;
(5) Any waters or wastes containing iron, chromium, copper, zinc and similar objectionable, or toxic substances to such degree that any such material received in the composite wastewater at the wastewater treatment works exceeds the limits established by the Public Works Director or MTDEQ for such materials;
(6) Any waters or wastes containing odor-producing substances exceeding limits which may be established by the Public Works Director or MTDEQ;
(7) Any radioactive wastes or isotopes of such half-life or concentration as may exceed limits established by the Public Works Director or MTDEQ in compliance with applicable state or federal regulations;
(8) Quantities of flow, concentrations or both, which constitute a “slug.” A slug is any discharge of water or wastewater which in concentration of any given constituent or in quantity of flow exceeds for any period of duration longer than 15 minutes more than five times the average 24-hour concentration or flows during normal operation and shall adversely affect the collection system and/or performance of the wastewater treatment works;
(9) Waters or wastes containing substances which are not amenable to treatment or reduction by the wastewater treatment processes employed or are amenable to treatment only to such degree that the wastewater treatment plant effluent cannot meet the discharge permit limits as dictated by MTDEQ; or
(10) Any water or wastes which, by interaction with other water or wastes in the public sewer system, release obnoxious gases, from suspended solids which, interfere with the collection system, or create a condition deleterious to structures and treatment processes.
(Prior Code, § 4.05.040) (Ord. 1, passed 1-17-1980; Ord. 20, passed 11-21-1983; Ord. 2021-10, passed 12-20-2021)