(a) The following described substances, materials, waters or wastes shall be limited in their discharge into wastewater works to concentrations or quantities which will not harm either the sewers or the wastewater treatment process or equipment, will not have an adverse effect on the receiving stream or will not otherwise endanger life, limb or public property or constitute a nuisance. The City Manager may set limitations lower than those established in this section if, in his or her opinion, such lower limitations are necessary to meet the objectives set forth in this section. In forming his or her opinion as to the acceptability of the materials, the City Manager will give consideration to such factors as the quantity of subject waste in relation to flows and velocities in the sewers, materials of construction of the sewers, the wastewater treatment process employed, the capacity of the water pollution control facility, the degree of treatability of the waste in the water pollution control facility and other pertinent factors. The materials prohibited without the approval of the City Manager are as follows:
(1) Wastewater having a temperature higher than 150 degrees Fahrenheit (sixty-five degrees Celsius);
(2) Wastewater containing more than 100 milligrams per liter of petroleum oil, nonbiodegradable cutting oils or products of mineral oil origin;
(3) Any garbage that has not been properly shredded. 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 for the purpose of delivery or service by caterers.
(4) Any water or waste containing strong acid iron pickling wastes, or concentrated plating solutions, whether neutralizing or not;
(5) Any water or waste containing iron, chromium, copper, zinc and similar objectionable or toxic substances to such a degree that any such material received in the composite wastewater at the water pollution control facility exceeds the limits established by the City Manager for such materials;