NR 110.24(5)(a)1.1. Embankments and dikes shall be constructed of relatively impervious materials and compacted at near optimum moisture content to 95% of the standard proctor density. NR 110.24(5)(a)2.2. Vegetation and other unsuitable materials shall be removed from the area where the embankment is to be placed. NR 110.24(5)(b)1.1. Riprap or other means of preventing erosion shall be used at locations on lagoon bottoms and interior dike walls where erosion or activity of burrowing animals is likely to occur. NR 110.24(5)(b)2.2. Riprap or other erosion control methods shall be used on the exterior dike walls for lagoons which are constructed in a flood fringe. NR 110.24(5)(b)3.3. Exterior dike walls, berms and interior dike walls above the normal operating water depth, shall be riprapped or seeded with perennial, low growing, spreading grasses. NR 110.24(5)(c)(c) Fencing. Lagoons shall be enclosed within a fence. A vehicle access gate shall be provided. NR 110.24(5)(d)(d) Warning signs. Appropriate signs shall be provided along the fence surrounding lagoons to designate the nature of the facility and prohibit trespassing. NR 110.24(6)(a)(a) Air requirements. Air shall be provided to the aerated lagoons at a rate of not less than 1.5 kilograms oxygen per kilogram (1.5 pounds of oxygen per pound) of peak hour BOD removed. NR 110.24(6)(b)1.1. The department may approve the use of surface aeration equipment only in those cases in which the equipment can be properly maintained and operated during the winter. NR 110.24(6)(b)2.2. Surface aeration equipment shall be so designed and placed to provide optimum mixing of pond lagoon contents and dispersion of oxygen to the waste. Unless sufficient justification is presented to the contrary, surface aerators shall be designed using an oxygen transfer rate of 1.2 kilograms of oxygen per kilowatt-hour (2.0 pounds of oxygen per horsepower-hour) in clean water under standard conditions. NR 110.24(6)(c)1.1. Flexible tubing containing air release slits shall be provided across the lagoon bottom in accordance with the manufacturer’s recommendations. Air tubing shall be securely anchored to prevent floating. To prevent clogging of the air lines, provision shall be made to accommodate cleaning. NR 110.24(6)(c)2.2. Air tubing and anchors shall be constructed of materials which resist corrosion. NR 110.24(6)(c)3.3. Air shall be supplied to the lagoon system at a rate sufficient to meet the oxygen requirements of par. (a) assuming an oxygen transfer efficiency of 7% in clean water under standard conditions. NR 110.24(6)(c)4.4. Tubular aeration units shall be provided in sufficient number to supply adequate air to the pond system based on a maximum transfer rate of 0.6 kilograms (1.25 pounds) of oxygen per unit per hour in clean water under standard conditions. NR 110.24(6)(c)5.5. Where data is presented to the department to justify oxygen transfer rates varying from the requirements of this paragraph the department may approve such design transfer rates. NR 110.24(6)(d)1.1. Multiple blowers shall be provided. Capacity of the blowers shall be sufficient to meet total air demands with one blower out of service. NR 110.24(6)(d)2.2. Diffusers and air piping shall be capable of supplying 200% of the average daily air demand. NR 110.24(7)(a)(a) Materials. Influent lines, interconnecting piping, and overflow structures shall be constructed of materials suitable for underground gravity sewer construction. NR 110.24(7)(b)2.2. Overflow structures and interconnecting piping for continuous flow lagoon systems shall be sized in accordance with s. NR 110.13 (4). NR 110.24(7)(b)3.3. Overflow structures and interconnecting piping for controlled discharge lagoon systems shall be sized to handle the anticipated interlagoon flow rates during periods of discharge. NR 110.24(7)(c)1.1. A manhole shall be installed at the end of the influent line or force main and shall be located as close to the dike as topography permits. Its invert shall be at least 15 centimeters (6 inches) above the maximum operating water level of the lagoon to provide sufficient hydraulic head without surcharging the manhole. NR 110.24(7)(c)2.2. Influent lines shall be located such that the top of the pipe is at least 15 centimeters (6 inches) below the lower surface of the soil, bentonite, or synthetic liner. NR 110.24(7)(c)3.3. For circular lagoons, the inlet shall terminate at the center of the lagoon. Influent lines to rectangular or square lagoons shall terminate in the first one third of the lagoon length. Influent and effluent piping shall be located to minimize short-circuiting within the lagoon. NR 110.24(7)(c)4.4. The inlet line shall discharge either horizontally onto a concrete pad or by means of an upturned elbow terminating at least 30 centimeters (one foot) above the pond bottom. NR 110.24(7)(d)(d) Overflow structures. An overflow structure shall be provided and shall consist of either a manhole or box equipped with multiple-valved pond drawoff lines or an adjustable overflow device. The overflow structure shall allow the liquid level of the lagoon to be adjusted to permit operation at depths ranging from 60 centimeters (2 feet) to the maximum design operating depth in stabilization ponds and from 1.2 meters (6 feet) to the maximum design operating depth in aerated lagoons. The department recommends that stop planks not be used in overflow structures to control operating depth. NR 110.24 HistoryHistory: Cr. Register, November, 1974, No. 227, eff. 12-1-74; r. and recr. Register, February, 1983, No. 326, eff. 3-1-83, am. (3) (c) and (4) (b), r. and rec. (3) (d), Register, November, 1990, No. 419, eff. 12-1-90; CR 09-123: am (2) (b) 2., 3., (3) (d) 3., (4) (d) 1., 3. to 5., (6) (a), (b) 2., (c) 3. and 4. Register July 2010 No. 655, eff. 8-1-10. NR 110.25NR 110.25 General conditions required for all land disposal systems. The provisions of this section apply to all municipal and privately owned domestic sewage treatment works. NR 110.25(1)(1) Applicability. Land disposal systems shall be reviewed and approved on a case-by-case basis. NR 110.25(3)(3) Treatment prior to disposal. All discharges to land disposal systems shall receive biological, chemical, physical or a combination of treatments necessary to meet effluent standards in ch. NR 206 and groundwater quality standards in ch. NR 140 as approved by the department. Industrial waste discharges tributary to the municipal system shall be in compliance with applicable pretreatment standards under s. NR 211.30. NR 110.25(3m)(a)(a) A management plan shall be submitted with plans and specifications for all land disposal facilities. NR 110.25(3m)(b)(b) The management plan shall contain specific information on pretreatment processes, scheduled maintenance, vegetative cover control and removal, load and rest schedules, application rates, operational strategies for periods of adverse weather, monitoring procedures and other pertinent information. NR 110.25(4)(a)1.1. The application rate of wastewater may not exceed the long term infiltrative capacity of the soil. NR 110.25(4)(a)2.2. The application rate of wastewater containing heavy metals may not exceed the soil capacity for preventing the movement of the heavy metals through the soil. NR 110.25(4)(a)3.3. Multiple wastewater application areas shall be provided to allow load and rest cycles. The discharge shall be alternately distributed to individual cells of the disposal system in a manner to allow sufficient resting periods to maintain the absorptive capacity of the soil, and to allow soil conditions to become unsaturated and aerobic between loadings. NR 110.25(4)(c)1.1. Land disposal systems shall be separated from private water supply wells by a minimum horizontal distance of 76 meters (250 feet). NR 110.25(4)(c)2.2. The minimum horizontal separation distance between a land disposal system and public water supply wells shall be determined during facilities planning in accordance with s. NR 110.09 (2) (p). In all cases the department recommends a minimum horizontal separation of 305 meters (1,000 feet) be maintained. NR 110.25(4)(e)(e) Storage lagoons. Storage lagoons shall be provided for all land disposal systems which are adversely affected by winter conditions or wet weather. Storage lagoons shall be constructed in accordance with s. NR 110.24 (3) and (4). NR 110.25(4)(f)(f) Load and rest cycles. Load and rest cycles for each system shall be determined based on hydrogeologic and other relevant site conditions such as soil permeability, texture, cation-exchange capacity, topography, depth to groundwater and bedrock and the wastewater characteristics. NR 110.25(4)(g)1.1. All precautions shall be taken during construction of a land disposal system to minimize compaction of absorption areas and to prevent reduction in soil infiltration rate. Project specifications shall detail the specific precautions to take, which may include no heavy equipment use and erosion control on berms. NR 110.25(4)(g)2.2. Erosion control measures shall be practiced during the construction of the land disposal system to avoid erosion of soil into a surface water and into or from the land disposal system. NR 110.25(5)(a)(a) Applicability. Groundwater monitoring systems shall be installed in accordance with approved plans and specifications as required in ch. NR 108, for the purpose of determining groundwater conditions for the engineering report in s. NR 110.09 (1) (b) and for WPDES permit requirements. Plans and specifications shall be prepared by a hydrogeologist or other qualified person. NR 110.25 NoteNote: The skills and knowledge required of a hydrogeologist making submittals under this chapter include: the ability to apply hydrogeologic principles and practices to the siting, design and operation of land disposal systems; knowledge of contaminants associated with land disposal of wastewater, their transport mechanisms and fate in the environment; familiarity with environmental monitoring practices, sampling techniques and groundwater standards; and proficiency in the design of groundwater monitoring systems for defining the physical and chemical characteristics of groundwater flow. A soil scientist or other environmental scientist who can demonstrate the above skills and knowledge, as reflected in submittals made under this chapter, shall be deemed a “qualified person”.
NR 110.25(5)(b)1.1. A minimum of 3 monitoring wells per land disposal system shall be installed to monitor groundwater quality in accordance with s. NR 206.10 (2), to determine flow directions and for a flow rate determination. At a minimum, one well will be upgradient and one well downgradient of the land disposal system. NR 110.25(5)(b)2.2. One or more upgradient monitoring wells shall be installed at locations and depths sufficient to yield groundwater samples that are representative of background water quality near the facility. Selection of well locations should take into account past and present land uses which might affect groundwater quality. The upgradient well should be located so it will not be affected by the land disposal system. Any upgradient wells should be located at the most distant point of upgradient of the application area, and not closer that 75 feet from the application area. If the well is located beyond the property boundary, an easement for access shall be obtained prior to installation of the well. NR 110.25(5)(b)3.3. Downgradient wells shall be located so as to intercept any groundwater impacted by the land disposal system, considering the vertical and horizontal gradients of flow. The wells shall be no closer than 30 feet for rapid infiltration systems, and at a minimum, one well shall be located between the application area and the design management zone (DMZ) or property boundary. It is recommended that one well be located at or beyond the DMZ or property boundary. If the well is located beyond the property boundary, an easement for access shall be obtained prior to installation of a well. NR 110.25(5)(c)(c) Monitoring well construction. All groundwater monitoring wells shall be constructed in accordance with ch. NR 141 and this section. NR 110.25(5)(c)1.a.a. For piezometers, inlet screens shall have a length of at least 2.5 feet but not more than 5 feet unless otherwise approved by the department. NR 110.25(5)(c)1.b.b. For water table observation wells, inlet screens shall not exceed 10 feet in length. NR 110.25(5)(c)1.c.c. For a multilevel groundwater system, the deeper the well shall be screened at a depth to be determined from the site investigation. NR 110.25(5)(c)3.3. All groundwater monitoring systems shall be sampled in accordance with department published groundwater sampling procedures as referenced in s. NR 140.16. NR 110.25(5)(c)4.4. All unsuccessful wells, boreholes or other vertical holes and wells whose use is no longer required must be properly abandoned in accordance with s. NR 141.25. NR 110.25(5)(c)5.5. Documentation of well construction, well development and abandonment shall be submitted to the department in accordance with ss. NR 141.23 and 141.25. A location map shall also be provided in accordance with s. NR 141.065. NR 110.25(5)(d)(d) Alternative methods and materials. The department may approve alternative construction methods or materials for installation of groundwater monitoring wells on a case-by-case basis. NR 110.25 HistoryHistory: Cr. Register, November, 1974, No. 227, eff. 12-1-74; r. and recr. Register, February, 1983, No. 326, eff. 3-1-83; cr. (intro.), (3m), (4) (a) 3. and (4) (g), am. (2), r. and recr. (3), (4) (f) and (5), Register, November, 1990, No. 419, eff. 12-1-90; CR 09-123: am. (5) (b) 1., 3., (c) 3. and 5. Register July 2010 No. 655, eff. 8-1-10. NR 110.255NR 110.255 Conditions required for specific types of land disposal systems. NR 110.255(1)(a)(a) Design and construction criteria for absorption pond systems. NR 110.255(1)(a)1.1. New absorption pond systems shall consist of a minimum of 3 individual absorption ponds of approximately equal size. Absorption pond systems consisting of 1 or 2 individual ponds may be approved by the department on a case-by-case basis if it is demonstrated that the system has effluent storage capabilities or other provisions to ensure the operation of the system in accordance with the load and rest cycles determined under s. NR 110.25 (4) (f). NR 110.255(1)(a)2.2. The design hydraulic application rate for an absorption pond system shall be based on field and laboratory test results for infiltration and hydraulic conductivity. The design hydraulic application rate shall be conservatively established to allow for pond resting cycles and for a long term reduction in infiltration rate due to wastewater solids clogging the soil. NR 110.255(1)(a)3.3. Multiple pond systems shall be designed and constructed to allow individual ponds to be taken out of service for resting without interrupting the discharge to the remaining ponds. NR 110.255(1)(a)4.4. Wastewater effluent shall be discharged to absorption ponds such that it is evenly distributed over the entire absorption pond bottom. Effluent storage may be required to provide effluent dosing control by fill and draw operation. NR 110.255(1)(a)5.5. The absorption pond bottom shall be as level as possible at all locations. NR 110.255(1)(a)6.6. The shape of each absorption pond and the placement of ponds at the site must take into account the information in the hydrogeologic study required by s. NR 110.09 (8) such as the groundwater flow direction, the presence of discharge or recharge zones and the variability of soils. Infiltration areas should be oriented in relation to the direction of groundwater flow in such a manner as to minimize groundwater impacts. When possible, absorption ponds shall be constructed in areas which are not groundwater recharge areas. NR 110.255(1)(a)7.7. The minimum top width of an embankment or dike shall be 12 feet if the dike is intended to provide access for maintenance vehicles on a routine basis. The minimum top width shall be 8 feet if the embankment or dike is not designed for vehicle access. Outside embankment and dike slopes may not be steeper than 3 horizontal to one vertical and shall be properly seeded with a mixture of grasses to prevent erosion. Inside embankments and dikes may not be steeper than 2 horizontal to one vertical and shall be properly graveled or riprapped to prevent erosion. Interior ramps for maintenance vehicle access are acceptable. NR 110.255(1)(a)8.8. Absorption ponds may not be constructed on backfilled material. Earthwork activities within 1 foot of the final pond surface shall be limited to times when soil conditions are dry. NR 110.255(1)(a)9.9. The bottom of the absorption pond may not be closer that 5 feet to the highest anticipated groundwater elevation. NR 110.255(1)(a)10.10. An absorption pond system shall be constructed on soils which meet with the following minimum requirements: NR 110.255(1)(a)10.a.a. Soil texture may not be coarser than loamy sand (USDA soils classification) or have less than 5% passing a number 200 sieve.
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Chs. NR 100-199; Environmental Protection – General
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