(a) It shall be unlawful for any person, until plans therefor have been submitted to and approved by the department and a written permit therefor shall have been granted to:

1. (1) Construct or install a disposal system or source;
2. (2) Make any change in, addition to or extension of any existing disposal system or part thereof that would materially alter the method or the effect of treating or disposing of the sewage, industrial waste or other wastes;
3. (3) Operate such new disposal systems or new source, or any existing disposal system or source;
4. (4) Increase the load through existing outlets of sewage, industrial waste or other wastes into the waters of the State.

(b) The director of Health and Environmental Control shall classify all public wastewater treatment plants, giving due regard to size, types of work, character, and volume of waste to be treated, and the use and nature of the water resources receiving the plant effluent. Plants may be classified in a group higher than indicated at the discretion of the classifying officer by reason of the incorporation in the plant of complex features which cause the plant to be more difficult to operate than usual or by reason of a waste unusually difficult to treat, or by reason of conditions of flow or use of the receiving waters requiring an unusually high degree of plant operation control or for combinations of such conditions or circumstances. The classification is based on the following groups:

1. (1) For biological wastewater treatment plants: Group I-B. All wastewater treatment plants which include one or more of the following units: primary settling, chlorination, sludge removal, imhoff tanks, sand filters, sludge drying beds, land spraying, grinding, screening, oxidation, and stabilization ponds. Group II-B. All wastewater treatment plants which include one or more of the units listed in Group I-B and, in addition, one or more of the following units: sludge digestion, aerated lagoon, and sludge thickeners. Group III-B. All wastewater treatment plants which include one or more of the units listed in Groups I-B and II-B and, in addition, one or more of the following: trickling filters, secondary settling, chemical treatment, vacuum filters, sludge elutriation, sludge incinerator, wet oxidation process, contact aeration, and activated sludge (either conventional, modified, or high rate processes). Group IV-B. All wastewater treatment plants which include one or more of the units listed in Groups I-B, II-B, and III-B and, in addition, treat waste having a raw five-day biochemical oxygen demand of five thousand pounds a day or more.
2. (2) Effective July 1, 1987, for physical-chemical wastewater treatment plants: Group I-P/C. All wastewater treatment plants which include one or more of the following units: primary settling, equalization, pH control, and oil skimming. Group II-P/C. All wastewater treatment plants which include one or more of the units listed in Group I-P/C and, in addition, one or more of the following units: sludge storage, dissolved air flotation, and clarification. Group III-P/C. All wastewater treatment plants which include one or more of the units listed in Groups I-P/C and II-P/C and, in addition, one or more of the following: oxidation/reduction reactions, cyanide destruction, metals precipitation, sludge dewatering, and air stripping. Group IV-P/C. All wastewater treatment plants which include one or more of the units listed in Groups I-P/C, II-P/C, and III-P/C and, in addition, one or more of the following: membrane technology, ion exchange, tertiary chemicals, and electrochemistry.