1. As used in this section, the term "effective secondary treatment" shall mean the removal of substantially all floating and settleable solids and the removal of at least eighty-five percent of suspended solids and at least eighty-five percent of five day biochemical oxygen demand, or such other standard as may be adopted pursuant to the Act.

2. The minimum degree of treatment required for the discharge of sanitary sewage into the surface waters of the state shall be effective secondary treatment, provided, however, that additional treatment may be required consistent with the standards established for specific waters by the department pursuant to section 17-0301 or with standards, criteria, limitations, rules or regulations promulgated or applied pursuant to title 8 hereof.