NR 204.07(6)(b)2.a.a. Agitate the sludge with air or oxygen to maintain aerobic conditions for a mean cell residence time and temperature between 40 days at 20° C and 60 days at 15° C; or NR 204.07(6)(b)2.b.b. Dry the sludge on sand beds or on paved or unpaved basins for a minimum of 3 months. During 2 of the 3 months, the ambient average daily temperature shall be above 0° C; or NR 204.07(6)(b)2.c.c. Treat the sludge in the absence of air for a specific mean cell residence time at a specific temperature. Values for the mean cell residence time and temperature shall be between 15 days at 35° to 55° C and 60 days at 20° C; or NR 204.07(6)(b)2.d.d. Compost the sludge using either the within-vessel, static aerated pile, or windrow composting methods and raise the temperature of the sludge to 40° C or higher for 5 days. For 4 hours during the 5 days, the temperature in the compost pile shall exceed 55° C; or NR 204.07(6)(b)2.e.e. Add sufficient lime to the sludge to raise the pH to 12 after 2 hours of contact; or NR 204.07(6)(b)2.f.f. Treat the sludge in a process that is equivalent to a process to significantly reduce pathogens, as approved by the department. NR 204.07(7)(7) Vector attraction reduction. Sludge may not be land applied unless one of the 11 vector attraction reduction options in pars. (a) to (k) is satisfied. Paragraphs (a) to (i) are processes which treat the sludge to reduce its attraction to vectors. Bagged sludge and exceptional quality sludge shall satisfy one of the requirements in pars. (a) to (i). The options are summarized in Table 7. NR 204.07(7)(a)(a) The mass of volatile solids in the sludge shall be reduced by a minimum of 38% between the time the sludge enters the digestion process and the time it either exits the digester or a storage facility; or NR 204.07(7)(b)(b) The specific oxygen uptake rate SOUR for aerobic sludge shall be equal to or less than 1.5 milligrams of oxygen per hour per gram of total solids on a dry weight basis, corrected to 20° Celsius; or NR 204.07(7)(c)(c) Demonstrate through additional digestion, in a bench-scale test, that additional volatile solids reduction for anaerobically digested sludge is less than 17%. This shall be demonstrated by digesting a portion of the previously digested sludge anaerobically in the laboratory in a bench-scale unit for 40 additional days at a temperature between 30° and 37° Celsius. This requirement is satisfied when, at the end of the test, volatile solids have been reduced by less than 17%, as measured from the beginning to the end of the test; or NR 204.07(7)(d)(d) Demonstrate through additional digestion, in a bench scale test, that additional volatile solids reduction for aerobically digested sludge is less than 15%. This shall be demonstrated by digesting a portion of the previously digested sludge, at a concentration of 2% solids or less, aerobically in the laboratory in a bench-scale unit for 30 additional days at a temperature of 20° Celsius. Sludge with higher percent solids shall be diluted with effluent down to 2% at the start of the test. This requirement is satisfied when, at the end of the test, volatile solids have been reduced by less than 15%, as measured from the beginning to the end of the test; or NR 204.07(7)(e)(e) Sludge shall be treated in an aerobic process for 14 days or longer. During that time, the temperature of the sludge shall be higher than 40° Celsius and the average temperature of the sludge shall be higher than 45° Celsius; or NR 204.07(7)(f)(f) The pH of the sewage sludge shall be raised to 12 or higher by alkali addition and, without the addition of more alkali, shall remain at 12 or higher for 2 hours and then at 11.5 or higher for an additional 22 hours; or NR 204.07(7)(g)(g) Dry the sludge to 75% total solids when the sludge contains no unstabilized solids from primary treatment; or NR 204.07(7)(h)(h) Dry the sludge to 90% total solids when the sludge contains unstabilized solids from primary treatment; or NR 204.07(7)(i)(i) Treat the sludge in a process which is equivalent to one of the vector attraction reduction requirements specified in pars. (a) to (h), as approved by the department. NR 204.07(7)(j)1.1. No significant amount of the sludge shall be present on the land surface within one hour after the sludge is injected. NR 204.07(7)(j)2.2. If the injected sludge is Class A, the sludge shall be injected within 8 hours after being discharged from the pathogen treatment process; or NR 204.07(7)(k)1.1. Class B sludge shall be incorporated within 6 hours, unless otherwise specified by the department. NR 204.07(7)(k)2.2. Class A sludge shall be surface applied within 8 hours after being discharged from a pathogen treatment process. It then shall be incorporated within 6 hours of surface application, unless otherwise specified by the department. NR 204.07(8)(a)(a) The amount of available nitrogen from sludge and other nitrogen sources applied per growing season may not exceed the nitrogen requirement of the crop, as determined by recommendations based on the University of Wisconsin-extension bulletin A-2100, dated April 1991 and incorporated by reference in s. NR 204.06 (6) (c). The department may authorize exceptions to this requirement on a case-by-case basis. Review for exceptions will consider proposals such as mine or other site reclamation projects. NR 204.07(8)(b)(b) Unless specific mineralization rates are determined by the permittee, the following mineralization rates are to be used in calculating the available organic nitrogen from initial sludge application and from carryover of previous years’ application: 25%-12%-6% in years 1 through 3. NR 204.07(8)(c)(c) Bulk sludge may be applied to all leguminous crops, except soybeans, at a volume sufficient to supply 200 pounds per acre of available nitrogen. If sludge is applied to soybeans, the loading shall be limited to 140 pounds per acre of available nitrogen. NR 204.07(8)(d)(d) Bulk sludge that is land applied and does not meet the pollutant concentrations in Table 3 of sub. (5) (c) may not be applied if the cumulative metals loadings listed in Table 2 of sub. (5) (b) have been reached. NR 204.07(8)(e)(e) The department shall be notified in writing, by the permittee, when 90% of the lifetime cumulative metal loadings has been reached on any site or field. From that point on, all loading to that site or field shall be individually monitored and reported.
