NR 110.255(4)(a)6.6. The distribution equipment shall be arranged so that the wastewater will be evenly distributed over the entire area of an overland flow cell and the wastewater travels down the slope in a non-channelized flow. NR 110.255(4)(a)7.7. The wastewater distribution equipment shall be located at or near the ground level. NR 110.255 NoteNote: A pressurized distribution system is recommended for ease of operation.
NR 110.255(4)(a)8.8. The wastewater distribution system shall be designed to allow for cleaning of the distribution orifices. Flexibility to adjust the flow from individual orifices shall be provided to allow the system to be hydraulically balanced to minimize flow channeling. NR 110.255(4)(a)9.9. An impermeable channel shall be provided for collecting runoff from the overland flow fields. The collection system shall be capable of removing the effluent and the rain from a 10-year frequency, 24-hour duration rainfall event with only temporary backing up of water onto the fields. NR 110.255(4)(a)10.10. The overland flow fields shall be vegetated with a water tolerant mixed perennial grass cover crop such as reed canary grass, tall fescue and orchard grass. A nurse crop shall be used to establish the perennial grass cover. The grass cover shall be maintained by frequent resting. The crop shall be cut and the cuttings removed at least twice per year to stimulate grass growth and enhance nutrient removal from the system. NR 110.255(4)(a)11.11. Winter operation may be allowed as long as the soil surface remains unfrozen. The department may require storage or additional treatment of the runoff during cold weather. NR 110.255(4)(a)12.12. An overland flow field may be used when the land surface elevation is at least 5 feet above bedrock. NR 110.255(4)(a)13.13. The land surface elevation of an overland flow field shall be no closer than 5 feet to the seasonally high groundwater level. The department may on a case-by-case basis allow this distance to be reduced if the permittee can show, based on hydrogeologic and other relevant site factors, that the groundwater will be adequately protected. If such a variance is approved or if the risk of groundwater contamination is otherwise high, the department may require additional pretreatment of the wastewaters. NR 110.255(4)(a)14.14. The hydraulic application rate, expressed as a flow rate per unit width of slope, shall be between .16 gpm/ft and .60 gpm/ft. NR 110.255(4)(b)(b) Discharge limitations for overland flow systems. Effluent limitations are as specified in s. NR 206.08 (4) (b) and applicable surface water limitations. NR 110.255 HistoryHistory: Cr. Register, November, 1990, No. 419, eff. 12-1-90. NR 110.26NR 110.26 Sludge handling, storage and disposal. NR 110.26(1)(1) Design report. A design report shall be submitted in accordance with s. NR 110.15 (1). The report shall show calculations used to design the sludge facilities. Design of sludge handling facilities shall consider such factors as the volume of sludge generated, its percent solids and character, the degree of volatile solids reduction, sludge temperature, the degree or extent of mixing to be obtained, the sludge percent solids and characteristics after processing and the size of the installation with appropriate allowances for sludge and supernatant storage and energy requirements whenever such factors are appropriate for the design of the sludge processing facilities. NR 110.26(2)(a)(a) Grit removal. When grit removal facilities are not provided, the volume of thickeners, digesters and storage facilities shall be increased to accommodate the additional solids loading. NR 110.26(2)(b)2.2. Thickened sludge should have a minimum solids concentration of 5% prior to transmission to the digesters. NR 110.26(2)(c)(c) Multiple units. Multiple units shall be provided. A single unit may be allowed, provided an alternate method of sludge processing, emergency storage or ultimate disposal operation exists to insure continuity of service. NR 110.26(2)(d)1.1. Provisions shall be made for draining, cleaning, inspection, and maintenance of all units. NR 110.26(2)(d)2.2. Tank bottoms shall be sloped to drain to a sump pump or withdrawal pipe. NR 110.26(2)(d)3.3. Access manholes shall be provided. Covered tanks shall have one side wall entrance large enough to permit the use of mechanical equipment to remove grit and sand. NR 110.26(2)(e)1.1. The construction of sludge storage facilities shall be required to improve sludge handling capabilities, provide flexibility in operations, and to avoid environmental or public health hazards due to improper disposal techniques. NR 110.26(2)(e)2.2. Construction of these facilities will depend upon treatment plant capabilities, land availability, surface and groundwater protection, health factors, municipal sludge management capabilities and other environmental factors. NR 110.26(3)(a)(a) Flow measurement. Devices for measuring flow to and from sludge digestion facilities shall be provided.