Section NR 214.18 - Sludge spreading systems(1) APPLICABILITY. Only sludges which have been exempted from regulation under ch. NR 518 and have been shown to have beneficial properties as a soil conditioner or fertilizer and not have detrimental effects on the soil, crops or groundwater may be spread on the land. A WPDES permit is required for the spreading of sludge on land.(2) SITE LOCATION CRITERIA. (a) All sites shall be approved by the department prior to sludge being spread.(b) Sludge may not be spread within 500 feet of any residence, except that this distance may be reduced to 200 feet if the sludge is incorporated with the soil and any affected owners and occupants give their written consent for the reduced separation distance.(c) Sludge may not be spread within 1000 feet of a well serving a community public water supply system or within 250 feet of any other potable water supply well.(d) Sludge may not be surface spread within 200 feet from any surface water course, dry run or wetlands, except that if a vegetative buffer strip is maintained between the site and the surface water, the department may approve a reduced separation distance to 100 feet. If the sludge is incorporated in the soil, the separation distance from any surface water may be reduced to a minimum of 50 feet.(e) Sludge may not be spread on wetlands or on areas subject to flooding or ponding.(f) Sludge spreading sites shall be limited to a slope of 12% or less when the soil temperatures are above freezing. When the ground is frozen or snow covered, the landspreading shall be restricted to sites with slopes of 2% or less. Sites with slopes of 2-6% may be approved for winter time spreading on a case-by-case basis.(g) Sludge spreading sites shall have at least 36 inches of separation between the ground surface and bedrock or groundwater. However, the department may allow a reduced separation distance to a minimum of 18 inches on a case-by-case basis provided the rate of application is reduced.(3) VEHICLE AND STORAGE CRITERIA. (a) Vehicles used for spreading shall be equipped with a distribution system capable of spreading the sludge evenly over the site.(b) Any system used for the storage or stacking of sludge prior to spreading shall be designed and constructed in accordance with ch. NR 213, or other design criteria as approved in the sludge management plan. Plans and specifications shall be submitted to the department for approval of such storage or stacking systems.(c) Storage or stacking systems shall be sited and operated to minimize odors or other public nuisance conditions.(4) DISCHARGE LIMITATIONS. (a) The discharge to a sludge spreading site may not exceed the hydraulic, organic, nitrogen, chloride or other limitations specified in a WPDES permit or plans developed pursuant to a permit requirement. In determining discharge limitations, the department shall consider past operating performance, the ability of the soils to treat the pollutants in the discharge, nutrient uptake of the cover crops, hydrogeologic characteristics of the site such as permeability and infiltration rates, and other relevant information.(b) The sludge application rate shall be limited so that any parameter that may impact groundwater quality is restricted to minimize the concentration of the substance in the groundwater to the extent technically and economically feasible and to prevent exceedence of the preventive action limit in the groundwater.(c) In order to prevent surface runoff and leaching and to control objectionable odors, the department may require liquid sludge to be incorporated into the soil surface within a time period specified in the WPDES permit. Cake sludge shall be incorporated in the soil in accordance with the time period specified in the sludge spreading management plan.(d) The total amount of any nutrient applied per year may not exceed the nutrient needs of the crop to be grown minus available nutrients in the soil or applied as fertilizer.(e) The pH of the sludge and soil mixture shall be 6.5 or higher at the time that the sludge is spread. If the concentration of cadmium in the sludge is 2 mg/kg (dry weight) or less, the soil pH may be less than 6.5.(f) No more than 0.45 pounds per acre of cadmium may be spread annually on land used for production of food chain crops.(g) The cumulative amount of cadmium, copper, lead, nickel and zinc spread on any site may not exceed the levels listed in Table 4. Table 4
Maximum Cumulative Cadmium, Copper, Lead, Nickel and Zinc Application for a Landspreading Site
Soil Cation Exchange Capacity (meq/100g)
Less than 5 lbs/ac | 5-10 lbs/ac | 10-15 lbs/ac | Greater than 15 lbs/ac |
Lead | 445 | 890 | 1,335 | 1,750 |
Zinc | 225 | 445 | 670 | 890 |
Copper | 110 | 220 | 335 | 445 |
Nickel | 45 | 90 | 135 | 180 |
Cadmium |
Soil pH<6.5 | 4.5 | 4.5 | 4.5 | 4.5 |
Soil pH>=6.5 | 4.5 | 9.0 | 13.5 | 18 |
(h) Sludge containing concentrations of PCBs equal to or greater than 10 mg/kg (dry weight) shall be incorporated into the soil when applied to land used for producing animal feed, including pasture crops for animals raised for the purpose of producing milk. The department may allow surface application of the sludge if it is assured that the PCB content is less than 0.2 mg/kg (actual weight) in animal feed or less than 1.5 mg/kg (fat basis) in milk from animals consuming the feed.(i) The department may limit or prohibit the land application of sludges containing additional pollutants such as, but not limited to phenolics, pesticides and bioaccumulative organics. Any such limit or prohibition shall be based on waste characteristics, soil cation exchange capacity, type of crop grown and other relevant factors.(5) DISCHARGE MONITORING REQUIREMENTS. (a) The discharge shall be monitored for total daily discharge volume.(b) The department may require in a WPDES permit that the sludge spreading discharge be monitored for total suspended solids, forms of nitrogen, chloride, metals or any other pollutant that may be present. The department shall select the pollutants to be monitored and the required frequency of monitoring on a case-by-case basis by considering the potential public health impacts, probable environmental impact, soil and geologic conditions, past operating performance, concentrations and characteristics of pollutants in the discharge and other relevant information.(c) The department may require the submittal of monitoring reports to include the following information for each site utilized during the reporting period: 1. The amount of sludge applied in tons per acre on a dry weight basis.2. The amount of nitrogen applied in pounds per acre on a dry weight basis.3. The amount of each metal applied in pounds per acre on a dry weight basis.4. Other site monitoring information as specified in the sludge management plan or WPDES permit.5. A description of any adverse environmental, health or social effects that occurred due to sludge application during the preceding reporting period.6. A description of any violation of the sludge management plan.(d) The department may require electronic or paper submittal of discharge monitoring reports and land application forms.(6) OPERATING REQUIREMENTS. (a) Spillage or leakage from vehicles used for transporting or spreading sludge shall be prevented.(b) The vehicle shall be moving forward at all times of application unless it is equipped with a high pressure spray nozzle which evenly distributes the sludge over the land.(c) Management plan. The department shall require each sludge spreading system owner or operator to submit a management plan for optimizing system performance and demonstrating compliance with the requirements of this chapter. Following approval by the department, the system shall be operated in conformance with the management plan. If the facility wishes to operate differently than specified in the approved plan, a written request shall be submitted to the department for approval to amend the management plan. The plan shall specify information on: sludge volumes and characteristics, beneficial or nondetrimental fertilizer or soil conditioner properties, production and pretreatment processes, description of all site limitations, vegetative cover control and removal, availability of storage, type of transportation and spreading vehicle, sludge application rates, load and rest schedules, contingency plans for periods of adverse weather, odor and nuisance abatement or any other pertinent information.(7) SOIL INVESTIGATION AND GROUNDWATER MONITORING REQUIREMENTS. Soil investigation and groundwater monitoring requirements are specified in ss. NR 214.20 and 214.21.Wis. Admin. Code Department of Natural Resources NR 214.18
Cr. Register, June, 1990, No. 414, eff. 7-1-90; CR 09-123: cr. (5) (d) Register July 2010 No. 655, eff. 8-1-10.