Section NR 113.09 - Application rates(1) GENERAL. (a) Land application to a site may not exceed the maximum hydraulic loading rates specified in Table 4 or nitrogen needs of the crop.(b) Septage may only be applied to agricultural lands and may not be applied at rates that will supply available nitrogen at amounts greater than the agronomic need for the crop grown as calculated under sub. (4).(c) Yearly loading rates listed in Table 4 may be used if the crop grown on a low use field requires 100 lbs-N/ac or more. If the crop requires less than 100 lbs-N/ac, the loadings shall be reduced in accordance with the equation under sub. (4).(2) HIGH USE FIELDS. The volume of septage applied annually on a high use field may not exceed the amount calculated under sub. (4) that is necessary to supply the nitrogen needs of the crop to be grown, as determined by the analysis of soil samples. The nitrogen crop needs shall be based on the University of Wisconsin - Extension bulletin A-2809 nutrient application guidelines for field, vegetable and fruit crops in Wisconsin, dated November 2012, which is incorporated by reference and soil samples shall be collected based on the University of Wisconsin extension bulletin A-2100, sampling soils for testing, dated January 2013, which is incorporated by reference or guidance approved by the department, except as allowed under sub. (3). Note: Copies of Bulletin A-2100, dated January 2013, and Bulletin A-2809, dated November 2012, are available for inspection in the offices of the department of natural resources and the legislative reference bureau.
(3) SPECIFIC CROPS ON HIGH USE FIELDS. Septage may be applied to most leguminous crops at a volume sufficient to supply 200 lbs/ac of available nitrogen. If septage is applied to soybeans, the loading shall be limited to 140 lbs/ac of available nitrogen.(4) ANNUAL AGRONOMIC RATE. For the purpose of implementing this section, septage may not be applied at a rate that exceeds the following: Annual Agronomic Rate (Gallons per acre per year) = Pounds of Nitrogen Required For the Expected Crop Yield per Acre/ 0.0026
Note: Under the federal nitrogen-hydraulic formula this estimates 2.5 lbs of nitrogen per 1,000 gallons of septage.
Note: The landowner or farmer may be subject to compliance with s. ATCP 50.04(3) and s. NR 151.07. Any application of nutrients shall be consistent with nutrient management plans under these state requirements and with any local requirements.
(5) MAXIMUM WEEKLY LOADING OF NON-GREASE INTERCEPTOR WASTE.(a)Weekly hydraulic rates. The maximum weekly hydraulic loading rate of septage application shall be limited by soil characteristics, and application method. The maximum weekly hydraulic loading rate is limited to 13,000 gallons per acre per week except that injection and incorporation on sites of 6 percent slope or less may be increased as follows: 1. For sites with predominately sandy loam, loam and silt loam, the weekly application rate may be increased with department approval to 27,000 gallons per acre per week.2. For sites with predominately clay loam, the weekly application rate may be increased with department approval to 20,000 gallons per acre per week.3. Prior to hydraulic application of septage greater than 13,000 gallons per acre per week, the licensee or WPDES permit holder shall submit a written request to the department for an increase in weekly hydraulic loading. The request shall include supporting information and be submitted under s. NR 113.11(1).4. After receiving a written request for an increased weekly hydraulic application rate from an applicant, the department shall determine the predominant soil texture at that site and evaluate if an increased weekly hydraulic loading rate is supported. The department, when making the determination of predominate soil texture, shall ensure the predominate soil texture within the top 12 inches of the soil profile and within the top 36 inches of the soil profile. The department shall document the evaluation in writing and provide the evaluation to the licensee or WPDES permit holder.5. When weekly application rates are approved by the department for greater than 13,000 gallon per acre per week, the department may require a management plan.(b)Ponding Prohibited. Ponding of septage shall be prohibited.(6) GREASE INTERCEPTORS. (ag) Waste from grease interceptors shall be disposed of at a department licensed sanitary landfill, discharged for treatment at a WPDES permitted POTW, land applied, or disposed or treated through some other department approved method. (ar) Contents of grease interceptors that are land applied to agricultural lands shall be incorporated, injected or mixed with septage at a level not to exceed 25 percent grease interceptor wastewater and applied in accordance with sub. (5). (b) The hydraulic loading rate for land application shall be limited by soil characteristics but under no conditions may exceed 4,300 gallons per acre per application for grease interceptor contents. Ponding of the grease interceptor wastewater is prohibited. Table 4
Summary of Maximum Loading Rates
Maximum Weekly Hydraulic Loading | Low Use Field2 Yearly Hydraulic Loading | High Use Field Yearly Hydraulic Loading |
Gal/Ac | Inches | Gal/Ac | Inches |
Non-Holding Tank POWTS Wastewater | 13,0003 | 1/2 | 39000 | 1-1/2 | Loading is based on crop requirements1 |
Non-Holding Tank POWTS Wastewater (75% or More) with Grease Trap Wastewater (25% or Less) | 13,0003 | 1/2 | 39000 | 1-1/2 | " |
Holding Tank POWTS Wastewater | 13,0003 | 1/2 | 39000 | 1-1/2 | " |
Holding Tank Non-POWTS Wastewater | 13,0003 | 1/2 | 39000 | 1-1/2 | " |
Holding Tank POWTS Wastewater (75% or More) Grease Trap Wastewater (25% or Less) | 13,0003 | 1/2 | 39000 | 1-1/2 | " |
Grease Trap Wastewater (All or Greater than 25% of a Mixed Load of Septage) | 4300 | 1/6 | 12900 | 1/2 | N/A |
1 The maximum annual hydraulic loading that will be permitted for any high use field will be based on the annual agronomic application rate computed by using the formula in sub. (4).
2 If the crop grown on a low use field requires less than 100 lbs N/ac, the max. annual hydraulic loading that is permitted is based on the annual agronomic application rate in sub. (4).
3 Weekly application rates may be increased over the standard rate of 13,000 gallon per acre per week under sub. (5) (a).
Wis. Admin. Code Department of Natural Resources NR 113.09
Cr. Register, September, 1996, No. 489, eff. 1-1-97.Amended by, CR 20-046: renum. (1) to (1) (b), (c) and am., cr. (1) (a), am. (2), (4), r. and recr. (5), renum. (6) (intro.), (a) to (6) (ag), (ar) and as renumbered, am. (6) (ag), am. (6) (b) Table 4 Register September 2021 No. 789, eff. 10-1-21; correction in (6) (ar) made under s. 35.17, Stats., Register September 2021 No. 789, eff. 10/1/2021