The physical characteristics of the treatment site and the surrounding area pose practical difficulties for construction of dry land access, and the treatment facility access is inundated by less than one foot of water during the regional flood. In these instances, the access roads shall be stabilized and delineated; or
The construction costs of the expansion or upgrading of an existing treatment facility are less than 50% of the value of the existing facility. The value of the existing facility shall be calculated by subtracting the 20-year total present worth of expanding or upgrading the existing facility from the 20-year total present worth of the most cost-effective treatment alternative located at another site which is not in a floodplain.
In order to minimize any potential odor, noise, and nuisances caused by sewage treatment facilities, and to enhance plant security and reliability, sewage treatment facilities shall be isolated from commercial establishments and from buildings occupied or intended for residential use, and from land which is actively being developed for commercial or residential use. The following separation distances shall be maintained:
150 meters (500 feet) for mechanical treatment facilities, effluent holding and polishing ponds;
150 meters (500 feet) for seepage cells, ridge and furrow systems, and overland flow systems;
305 meters (1,000 feet) for off site sludge holding facilities and spray irrigation systems; and
The department may waive the requirements of subd. 1.
if the requirements prevent implementation of the cost-effective treatment alternative at an existing sewage treatment facility site. When a waiver is requested, the owner shall demonstrate to the department that:
The owner has made reasonable attempts to obtain an agreement from any affected property owner which states that the property owner has been informed of the potential nuisances which may result from the operation of the sewage treatment facilities and that the property owner does not object to the construction and operation of the sewage treatment facilities; and
The treatment facility owner has enacted a zoning ordinance which prohibits future construction within the applicable separation distances, or has purchased sufficient land surrounding the sewage treatment facility to prevent future encroachment.
The department may waive the requirements of subd. 1.
if the requirements prevent construction of the cost-effective treatment alternative at a new site. When a waiver is requested the owner shall demonstrate that:
The treatment facility has obtained from the affected property owners the agreements described in subd. 2. a.
or that the proposed sewage treatment facility site is the only reasonably available site or, the costs associated with using another site would place an unreasonable or excessive financial burden on the community; and
The treatment facility owner has enacted a zoning ordinance which prohibits future construction within the applicable separation distances, or has purchased sufficient land surrounding the proposed treatment facility site to prevent future encroachment.
(e) Protection of water supply wells.
Wastewater lagoons or storage structures shall be located with a minimum separation distance of 1,000 feet from a community water system well, and 100 feet from a private water system well or any other well subject to ch. NR 812
. Wastewater treatment plant effluent pipes shall be located with a minimum separation distance of 50 feet from a private water system well or any other well subject to ch. NR 812
NR 110.15(4)(a)(a) Conformance with facilities plan.
The design capacity for municipally owned sewage treatment facilities shall be in accordance with s. NR 110.09 (2) (j)
. Privately owned domestic sewage treatment facilities shall provide design capacity for the estimated population 20 years from the time of start-up of the facility unless the cost-effective staging analysis in s. NR 110.09 (2) (j) 4.
justifies a lesser design staging period.
The domestic design biochemical oxygen demand and suspended solids loading for upgrading or expanding existing sewage treatment facilities, or for the construction of new sewage treatment facilities to replace an existing facility shall be based on actual sewage and operating records from the existing facilities. The design shall include an appropriate growth increment.
When actual operating data is not available, the design loading shall be based on a contribution of 0.08 kilograms (0.17 pounds) of biochemical oxygen demand per capita per day and 0.09 kilograms (0.20 pounds) of suspended solids per capita per day. When garbage grinders are used in areas tributary to a sewage treatment facility, the design basis shall be increased to 0.10 kilograms (0.22 pounds) of biochemical oxygen demand per capita per day, and 0.22 kilograms (0.25 pounds) of suspended solids per capita per day.
Sewage treatment facilities which will receive industrial or commercial wastewater shall be designed to include these waste flows.
(c) Hydraulic loading.
The design wastewater flow shall be estimated in accordance with s. NR 110.09 (2) (j)
. When flow or water use records do not exist, the maximum hour design flow shall be estimated by multiplying the average design flow by the appropriate peaking factor shown in Table 2.
NR 110.15(5)(a)(a) Design of conduits.
All piping and channels shall be designed to carry the peak design flow rate. The incoming sewer should be designed for unrestricted flow. Bottom corners of the channels must be filleted. Conduits shall be designed to avoid creation of pockets and corners where solids can accumulate. Suitable gates shall be placed in channels to seal off unused sections in which solids might accumulate. The use of shear gates or stop planks may be used in place of gate valves or sluice gates.
(b) Arrangement of units.
Component parts of the facility shall be arranged for greatest operating and maintenance convenience, flexibility, economy, continuity of effluent quality, and ease of installation of future units.
(c) Flow measurement.
Equipment for flow measurement and recording shall be provided for the total waste flow. Equipment for measuring flow streams within the treatment facility should be provided to aid facility operation.
(d) Emergency operation.
One of the following provisions shall be made to insure continued operation of the sewage treatment facility in accordance with sub. (2) (d)
An emergency power generator may be provided. The generator shall have sufficient generating capacity to meet the treatment facility power demands needed to comply with sub. (2) (d)
The sewage treatment facility electrical system may be connected to 2 independent electrical transmission routes which receive power from the same electrical grid network which supplies power to the treatment facility service area; or
The sewage treatment facility may be equipped with holding facilities which have a capacity to detain the maximum daily design flow for a minimum period of 24 hours.
(e) New processes, methods and equipment.
The department encourages the development of new process, methods, or equipment for the treatment of sewage. However, where new processes, methods, or equipment are proposed and where limited data is available which demonstrates the performance of the equipment, the department may require written certification that the use or design of the equipment is in accordance with the manufacturer's guidelines. Furthermore, the department may require the posting of a performance bond by the manufacturer.
Disinfection shall be provided in accordance with WPDES permit requirements.
(g) Unit bypasses.
Unit bypasses shall be located and arranged to allow for proper maintenance of the treatment facility while complying with the provisions of sub. (2) (c)
. In all cases, it must be possible for each treatment unit to be independently removed from service.
(h) Total treatment facility bypasses.
Total treatment facility bypasses may be permitted in accordance with sub. (2) (e)
. Design of treatment facility bypass structures shall meet the following requirements:
Design of a treatment facility bypass structure shall require the deliberate and conscious effort of the treatment facility operator to place the bypass into operation. Automatic bypasses are prohibited.
Bypass structures shall be used to conduct only those wastewater flows above the peak flow rate which the treatment plant can safely handle without threatening loss of life, severe property damage, or the washout of treatment media.
The means for measuring and sampling bypassed sewage shall be provided at all bypass structures.
The use of paints containing lead is prohibited. In order to facilitate the identification of piping, pipes shall be painted as follows:
Nonpotable water line—blue with 15 centimeter (6 inch) red bands spaced 76 centimeters (30 inches) apart.
In addition to the color code, each pipe shall be adequately labeled with a minimum of 2 labels in each room, crawl space or compartment.
Existing treatment facilities which do not comply with the provisions of this subsection shall bring the facility into compliance at the time of any major upgrading or expansion of the facility.
(j) Valve identification.
All valves shall be identified in the plans and specifications and labeled during construction.
(k) Operational considerations.
All necessary tools and accessories for the facility operator's use shall be provided. Storage space and a work area shall also be provided. All equipment shall be located as to provide sufficient clearance for proper and convenient maintenance. All tanks, wet wells, channels and pipe systems shall be equipped with drains, valves, or sumps to facilitate draining for maintenance and repair.
(L) Laboratory space and equipment.
A treatment facility owner shall either include a laboratory for making the necessary analytical determinations and operating control tests, or contract with a neighboring facility or independent laboratory to have the analytical and operating control tests done.
(m) Floor slope.
Floor surfaces shall be sloped adequately to a point of drainage.
(n) Erosion control during construction.
Effective site erosion control shall be provided during construction. Project specifications shall detail erosion control methods. Manner of spoil material disposal shall also be detailed.
(o) Construction materials.
Materials shall be selected that are compatible with the wastewater characteristics. Dissimilar metals should be avoided to minimize galvanic action.
(p) Sanitary facilities.
Toilet, shower, lavatory, and locker facilities should be provided in sufficient numbers and convenient locations to serve the expected facility personnel. Toilet, shower, and lavatory facilities shall be provided in the following instances:
Any sewage treatment facility equipped with laboratory facilities;
Any sewage treatment facility equipped with a potable water supply; or
Any sewage treatment facility which has one or more full time operating personnel.
Sewage treatment facilities shall be enclosed with a fence to discourage entry of animals or unauthorized persons.
Hand rails shall be installed around all treatment tanks and in other areas of the facility where the potential of falling exists.
The department recommends the following safety measure be considered in the design of wastewater treatment facilities:
Provision of protective clothing and equipment such as gas masks, goggles, gloves, hard hats, and safety harness;
The safety and health rules set forth in ch. SPS 332
, and appropriate federal and local safety codes shall be adhered to in the operation of wastewater treatment plants.
NR 110.15(6)(a)(a) Potable supply.
Any sewage treatment facility which has a laboratory shall be provided with a potable water supply.
Sewage treatment facility plumbing systems shall be designed in accordance with ch. SPS 382
(c) Connection to public water systems.
Connection of a sewage treatment facility plumbing system to a public water system shall comply with the requirements of s. NR 811.25
and ch. SPS 382
(d) On-site wells.
Construction of wells for supplying water to a sewage treatment facility shall comply with the requirements of the approval obtained under s. NR 812.26 (3)
NR 110.15 History
Cr. Register, November, 1974, No. 227
, eff. 12-1-74; r. and recr. (1) (c), Register, March, 1978, No. 267
, eff. 4-1-78; r. and recr. Register, February, 1983, No. 326
, eff. 3-1-83, cr. (4) (d), Register, November, 1990, No. 419
, eff. 12-1-90; corrections in (5) and (6) made under s. 13.93 (2m) (b) 7., Stats., Register, September, 1995, No. 477
; corrections in (5) (q) 4., (6) (b), and (c) were made under s. 13.93 (2m) (b) 7., Stats., Register, May, 2001, No. 545
; CR 09-123
: am. (2) (a) and (4) (c), cr. (3) (e) Register July 2010 No. 655
, eff. 8-1-10; corrections in (5) (q) 4., (6) (b) and (c) made under s. 13.92 (4) (b) 7., Stats., Register January 2012 No. 673
NR 110.16(1)(a)(a) Applicability.
All wastewater treatment plants shall be provided with protection for pumps and other equipment by installing coarse screens, bar racks, mechanically cleaned bar racks or comminutors.
Screening devices installed in a building where other equipment or offices are located shall be separated from the rest of the building and provided with separate outside entrances.
Screening devices may not be located such that changes in backwater elevations will interfere with the accuracy of upstream flow measuring equipment.