Current through Register Vol. 47, No. 11, December 11, 2024
Rule 567-81.3 - Wastewater treatment plant grades(1)Classifications. The wastewater treatment plant classifications are listed in the following table: Wastewater Treatment Plant Classifications
Treatment Type | Grade |
Based on Design Pounds of BOD5/day |
less than 334 | 334-835 | 836-2,505 | 2,506-8,350 | more than 8,350 |
Based on Design Population Equivalent |
less than 2,000 | 2,000-5,000 | 5,00115,000 | 15,00150,000 | more than 50,000 |
1. Onsite Treatment System | W | Not Applicable | Not Applicable | Not Applicable | Not Applicable |
2. Waste Stabilization Lagoon System | IL | IL | IL | IL | IL |
3. Aerated Lagoon System | IL | IL | I | I | I |
4. Advanced Aerated Lagoon System | II | II | II | II | II |
5. Fixed Film Biological Treatment System | II | II | III | III | IV |
6. Activated Sludge System | II | III | III | IV | IV |
(2)Unknown design BOD5 loading. When the design BOD5loading is unknown, the plant BOD5loading shall be determined by using the average pounds of BOD5of the 24-hour composite influent samples taken in the last 12 months. If 24-hour composite influent samples are not available, then grab samples shall be used.(3)IL wastewater operator requirements. A Grade I, II, III, or IV wastewater treatment certificate will satisfy the certification requirements for a Grade IL plant.(4)Grade W onsite wastewater classification. Any wastewater treatment plant that discharges to a water of the state and that utilizes onsite wastewater treatment technologies, such as those specified in 567-Chapter 69, but excluding waste stabilization ponds, shall be classified as an onsite treatment system (Grade W).Iowa Admin. Code r. 567-81.3
Amended by IAB February 9, 2022/Volume XLIV, Number 16, effective 3/16/2022