MOUND COMPONENT MANUAL FOR PRIVATE
Contents
1. J _5 61 or_5 6_ feet b Down slope width I Fill depth at down slope edge of distribution cell E F G x Horizontal gradient of side slope x Down slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 I E F G x Horizontal gradient of side slope x Down slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 I 14 25 in 9 5 in 6 in 12 in ft x 3 x 100 100 3 x 6 I 29 75 in 12 in ft x 3 x 100 82 I 9 07 or 9 1 feet c Mound width W Up slope width J Distribution cell width A Down slope width 1 W J A I W 5 6 ft 45 ft 9 1 ft W 19 2 feet 37 of 44 4 Check the basal area a Basal area required Daily wastewater flow soil application rate of in situ soil The soil application rate may be that which is listed for BOD and TSS gt or lt 30 mg L depending on wastewater characteristics or fill depth below distribution cell See Table 1 450 gal day 0 3 gal ft day 1500 ft b Basal area available 1 Sloping site Cell length B x of cells x cell width of cells 1 x cell spacing down slope width A D 100 ft x 1 x 4 5 ft 1 1 x Oft 9 5 ft 100 ft x 4 5 ft 0 ft 9 5 ft 100 ft x 14 ft 1400 f 2 Level site Cell length B x total mound width W ft x ft f c Is available basal area sufficient yes x no Ba2. e Separate sheet showing the location of all borings The location of all borings and backhoe pits must be able to be identified on the plot plan Documentation e Architects engineers or designers must sign seal and date each page of the submittal or provide an index page which is signed sealed and dated e Master Plumbers must sign date and include their license number on each page of the submittal or provide an index page which is signed sealed and dated e Three completed sets of plans and specifications clear permanent and legible submittals must be on paper measuring at least 8 1 2 by 11 inches e Designs that are based on department approved component manual s must include reference to the manual by name publication number and published date 40 of 44 Plot Plan e Dimensioned plans or plans drawn to scale scale indicated on plans with parcel size or all property boundaries clearly marked e Slope directions and percent in system area e Bench mark and north arrow e Setbacks indicated as per appropriate code e Two foot contours or other appropriate contour interval within the system area e Location information legal description of parcel must be noted e Location of any nearby existing system or well Plan View e Dimensions for distribution cell s e Location of observation pipes e Dimensions of mound e Pipe lateral layout which must include the number of laterals pipe material diameter and
3. Hof bedrooms Public Facility __0 _ gal day Estimated wastewater flow Depth to limiting factor __25 inches Minimum depth of unsaturated soil required by Table 383 44 3 Wis Adm Code 36 inches In situ soil application rate used 0 3 gal f day FOG value of effluent applied to component _ lt 30 mg L BOD value of effluent applied to component 180 mg L TSS value of effluent applied to component _50 mg L Fecal Coliform monthly geometric mean value of effluent applied to component gt 10 cfu 100ml X Yes _ No Type of distribution cell X Stone aggregate or__ Leaching chamber B DESIGN WASTEWATER FLOW DWF One or Two family Dwelling Combined wastewater flow DWE 150 gal day bedroom x of bedrooms 150 gal day bedroom x _3_ of bedrooms 450 gal day Clearwater and graywater only DWE 90 gal day bedroom x of bedrooms 90 gal day bedroom x _____ F of bedrooms z gal day 33 of 44 Blackwater only DWE 60 gal day bedroom x of bedrooms 60 gal day bedroom x of bedrooms gal day Public Facilities DWF Estimated wastewater flow x 1 5 gal day x 1 5 gal day C DESIGN OF THE DISTRIBUTION CELL 1 Total size the Distribution cell s area a Loading rate of fill material _X_ lt 1 0 gal ft day if BOD or TSS gt 30 mg L or ___ 2 0 gal ft day if BOD or TSS lt 30 mg L b Bottom area of distribution cell Design wastewater flow loading rate of fill material a
4. OPERATION MAINTENANCE AND PERFORMANCE MONITORING The component owner is responsible for the operation and maintenance of the component The county department or POWTS service contractor may make periodic inspections of the components checking for surface discharge treated effluent levels etc The owner or owner s agent is required to submit necessary maintenance reports to the appropriate jurisdiction and or the department Design approval and site inspections before during and after the construction are accomplished by the county or other appropriate jurisdictions in accordance to ch SPS 383 of the Wis Adm Code C Routine and preventative maintenance aspects 1 Treatment and distribution tanks are to be inspected routinely and maintained when necessary in accordance with their approvals 2 Inspections of the mound component performance are required at least once every three years These inspections include checking the liquid levels in the observation pipes and examination for any seepage around the mound component 3 Winter traffic on the mound is not advised to avoid frost penetration and to minimize compaction 4 A good water conservation plan within the house or establishment will help assure that the mound component will not be overloaded 23 of 44 D User s Manual A user s manual is to accompany the component The manual is to contain the following as a minimum 1 Diagrams of all components and their lo
5. of cells x cell width of cells B x A Hp 1 x cell spacing down slope width Effluent application By use of pressure distribution network conforming to sizing methods of either Small Scale Waste Management Project publication 9 6 entitled Design of Pressure Distribution Networks for Septic Tank Soil Absorption Systems or Dept of Commerce publications SBD 10573 P or SBD 10706 P entitled Pressure Distribution Component Manual for Private Onsite Wastewater Treatment Systems Meets requirements of s SPS 384 30 2 Wis Adm Code for its intended use Meets requirements of s SPS 384 30 6 i Wis Adm material Code Geotextile fabric meeting s SPS 384 30 6 g Wis when stone aggregate is used Adm Code distribution cell Location of observation pipes for Observation pipes will be installed in each distribution cell so as level components to be representative of a cell s hydraulic performance be located such that there are a minimum of two installed in each dispersal cell at opposite ends from one another Location of observation pipes for be located near the dispersal cell ends components on a slope be at least 6 inches from the end wall and sidewall be installed at an elevation to view the horizontal or level infiltrative surface within the dispersal cell Observation pipes may be located less than 6 inches from end walls or side walls if specified in state approved manufacturers in
6. F G x Horizontal gradient of side slope x Down slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 I E F G x Horizontal gradient of side slope x Down slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 I in in in 12 in ft x x 100 100 x or I in 12 in ftx 3 x 100 I feet c Mound width W Up slope width J Distribution cell width A Down slope width 1 W J A I W ft ft ft W feet 30 of 44 4 Check the basal area a b Basal area required Daily wastewater flow soil application rate of in situ soil The soil application rate may be that which is listed for BOD and TSS gt or lt 30 mg L depending on wastewater characteristics or fill depth below distribution cell See Table 1 gal day gal ft day ft Basal area available 1 Sloping site Cell length B x of cells x cell width of cells 1 x cell spacing down slope width A D ftx x_ ft ___ 1 x__ft __ ft ft x ft ft ft ft x ft ft 2 Level site Cell length B x total mound width W ft x ft ft Is available basal area sufficient ___ yes no Basal area required lt Basal area available ft lt f See d for recalculation of basal area 31 of 44 d Basal area available recalculation of basal area 1 Sloping site Cell
7. Formula 8 Percent of Deflection Deflection Effective distribution cell length x 100 Where Deflection Maximum distance between the down slope edge of a concave distribution cell to the length of a perpendicular line that intersects furthest points of the contour line along the down slope edge of the distribution cell Effective distribution cell length Distance between the furthest points along the contour line of the down slope edge of the concave distribution cell 100 Conversion factor The actual distribution cell length must be checked to determine if the cell area is sufficient The actual distribution cell length is calculated using Formula 9 Formula 9 Actual distribution cell length of deflection x 0 00265 1 x effective distribution cell length Where of deflection Determined by Formula 8 0 00265 Conversion factor from percent to feet 1 Constant Percent of deflection Deflection Effective Cell Length x 100 Distribution Cell A Petecton gt Effective Cell Length of Concave Distribution Cell ado s jo uonsaig Figure 4 Simple Concave Distribution Cell 15 of 44 Distribution Cell a Defecto Effective Cell Length of Concave Distribution Cell ado s jo u40N9311 Percent of deflection Deflection Effective Cell Length of Concave Distribution Cell x 100 Figure 5 Complex Concave Distribution Cell Step C Sizing the Mound 1 Mound Height The moun
8. and two family dwelling application is determined by calculating the design wastewater flow DWF To calculate DWF use Formulas 1 2 or 3 Formula 1 is for combined wastewater flows which consist of blackwater clearwater and graywater Formula 2 is for only clearwater and graywater Formula 3 is blackwater only Formula 1 Formula 2 Formula 3 Combined wastewater Clearwater amp Graywater Blackwater DWE 150 gal day bedroom DWF 90 gal day bedroom DWF 60 gal day bedroom Public Facilities Distribution cell size for public facilities application is determined by calculating the DWF using Formula 4 Only facilities identified in Table 4 are included in this manual Estimated daily wastewater flows are determined in accordance with Table 4 or s SPS 383 43 6 Wis Adm Code Many commercial facilities have high BODs TSS and FOG fats oils and grease which must be pretreated in order to bring their values down to an acceptable range before entering into the mound component described in this manual Formula 4 DWE Sum of each estimated wastewater flow per source per day x 1 5 Where 1 5 Conversion factor to convert estimated wastewater flow to design wastewater flow 10 of 44 Table 4 Public Facility Wastewater Flows Source Apartment or Condominium Assembly hall no kitchen Bar or cocktail lounge no meals served Bar or cocktail lounge w meals all paper service Beauty salon Bowling alley Bowling
9. cell B x width of fill and cover W beneath the fill and soil cover is available for effluent absorption into the soil see Figure 7a For sloping sites the available basal area is the area down slope of the up slope edge of the distribution cell to the down slope edge of the fill and soil cover or A I times the length of the distribution cell B see Figure 7b The up slope width and end slopes are not included as part of the total basal area It is important to compare the required basal area to the available basal area The available basal area must equal or exceed the required basal area 19 of 44 i Es qu 1 ie A BA E y A o o p Figure 7a Level site Figure 7b One direction slope Basal area required DWF Infiltration rate of in situ soil Basal area available B x W on a level site or B x A D on a sloping site If sufficient area is not available for the given design and site conditions corrective action is required to increase J and I on level sites or I on sloping sites 7 Location of the observation pipes Observation pipes will be installed in each distribution cell so as to be representative of a cell s hydraulic performance e be located such that there are a minimum of two installed in each dispersal cell at opposite ends from one another e be located near the dispersal cell ends e beat least 6 inches from the end wall and sidewall e be installed at an elevation to view the horizon
10. cover There should be approximately two feet of basal area adjacent to the mound perimeter that is not covered by the sand fill This area serves to tie the soil cover into the natural surface material that has been tilled and helps seal the toe from leakage Work from the end and up slope sides This will avoid compacting the soils on the down slope side which if compacted affects lateral movement away from the fill and could cause surface seepage at the toe of the fill on slowly permeable soils 7 Move the fill material into place using a small track type tractor with a blade or a large backhoe that has sufficient reach to prevent compaction of the tilled area Do not use a tractor backhoe having tires Always keep a minimum of 6 inches of fill material beneath tracks to prevent compaction of the in situ soil 8 Place the fill material to the required depth 9 Form the distribution cell Hand level the bottom of the distribution cell If using leaching chambers hand tamp fill where chambers will be located NOTE If using leaching chambers go to step 15 10 Install the required observation pipes with the bottom 6 inches of the observation pipe slotted Installations of all observation pipes include a suitable means of anchoring See Figure 8 11 Place the stone aggregate in the distribution cell Level the stone aggregate to the design depth Water tight cap Top of leaching Repair couplings Water Closet Coll
11. determined in C 1 a Distribution cell area _ 450 gal day _1 0 gal ft day Distribution cell area 450 f 2 Distribution cell Configuration a Distribution cell width s A 7 feet lt 10 ft and the number of distribution cells _1 cells b Distribution cell length B Bottom area of distribution cell width of distribution cell B _450 ft Distribution cell area required _7_ft A B 64 29 or 65 ft c Check distribution cell length B For linear loading rate Linear Loading Rate lt Design Wastewater Flow Cell length B or effective cell length for a concave mound Linear Loading Rate lt _450_ gal day _65_ ft Linear Loading Rate lt _6 92_ gal ft Linear loading rate for systems with in situ soils having an soil application rate of lt 0 3 gal ft day within 12 inches of fill must be less lt 4 5 gal ft day 34 of 44 Is the linear loading rate lt what is allowed __ yes _ x__ no If no then the length and or width of the distribution cell must be changed so it does Distribution cell length B Design Wastewater Flow Maximum Linear Loading Rate Distribution cell length B _450_ gal day _4 5_ gal ft day Distribution cell length B _100 ft Distribution cell width A _450_ ft Distribution cell area 100 ft B Distribution cell width A _4 5_ ft d Check percent of deflection and actual length of concave distribution cell length Percent of deflection Deflection Effective di
12. sizing as described in either Small Scale Waste Management Project publication 9 6 entitled Design of Pressure Distribution Networks for Septic Tank Soil Absorption System or Dept of Commerce publications SBD 10573 P or SBD 10706 P entitled Pressure Distribution Component Manual for Private Onsite Wastewater Treatment Systems is acceptable Component Design Design of the mound system is based upon the design wastewater flow and the soil characteristics It must be sized such that it can accept the design wastewater flow without causing surface seepage or groundwater pollution Consequently the basal area which is the in situ soil area beneath the fill must be sufficiently large enough to absorb the effluent 9 of 44 into the underlying soil The system must also be designed to avoid encroachment of the water table into the required minimum unsaturated zone Design of the mound includes the following three steps A calculating design wastewater flow B design of the distribution cell within the fill C design of the entire mound This includes calculating total width total length system height distribution lateral location and observation pipes Each step is discussed A design example is provided in section XI of the manual The letters for the various dimensions correlate with those in Figures 2 and 3 Step A Design Wastewater Flow Calculations One and two family dwellings Distribution cell size for one
13. MOUND COMPONENT MANUAL FOR PRIVATE ONSITE WASTEWATER TREATMENT SYSTEMS VERSION 2 0 October 2012 State of Wisconsin Department of Safety amp Professional Services Division of Safety and Buildings SBD 10691 P N 01 01 R 10 12 Page 1 of 44 MOUND COMPONENT MANUAL FOR PRIVATE ONSITE WASTEWATER TREATMENT SYSTEMS TABLE OF CONTENTS Page I Introduction and Specifications 3 Il Definitions 6 Il Description and Principle of Operation 7 IV Soil and Site Requirements 8 V Fill and Cover Material 9 VI Design 9 VII Site Preparation and Construction 21 VIU Operation Maintenance and Performance Monitoring 23 IX References 24 X Mound Worksheet 25 XI Example Worksheet 33 XII Plan Submittal and Installation Inspection 40 Republished on October 2012 by Department of Safety amp Professional Services Division of Industry Services Publication SBD 10691 P N 01 01 R 10 12 Previously Published in January 2001 by Department of Commerce Division of Safety and Buildings ADA Statement The Department of Safety amp Professional Services is an equal opportunity service provider and employer If you need assistance to access services or need material in an alternate format please contact the Department at 608 266 3151 Deaf hearing or speech impaired callers may reach the Department through WI TRS Wisconsin Telecommunication Relay System 2 of 44 I INTRODUCTION AND SPECIFICATIONS This Private Onsite Wastewater
14. TE OF REFERRAL TO LEGAL COUNSEL COMMENTS Persons present discrepancies etc COMPONENTS NOT INSPECTED Plan Revision Required Date Signature of Inspector Cert Number L Yes L No Sketch on other side 43 of 44 ELEVATION DATA Page 2 of 2 Point Back Height of Foresight Elevation Comments sight instrument Benchmark Blag Sewer Tankinlet J po Tankoutlet J Tankinlet J Tank outlet J pp inlet dose tank Dist lateri Systemelev 1 Dist lateral2 Systemelev 2 Dist lateral3 System elev 3 ______ Gradeelev 1 Grade eley 2 Gradeelev 3 Jo SKETCH OF COMPONENT amp ADDITIONAL COMMENTS 44 of 44
15. Treatment System POWTS component manual provides design construction inspection operation and maintenance specifications for a mound component However these items must accompany a properly prepared and reviewed plan acceptable to the governing unit to help provide a system that can be installed and function properly Violations of this manual constitute a violation of chs SPS 383 and 84 Wis Adm Code The mound component must receive influent flows and loads less than or equal to those specified in Table 1 When designed installed and maintained in accordance with this manual the mound component provides treatment and dispersal of domestic wastewater in conformance with ch SPS 383 of the Wis Adm Code Final effluent characteristics will comply with s SPS 383 41 Wis Adm Code when inputs are within the range specified in Tables 1 to 3 Note Detailed plans and specifications must be developed and submitted for reviewed and approved by the governing unit having authority over the plan for the installation Also a Sanitary Permit must be obtained from the department or governmental unit having jurisdiction See Section XII for more details Table 1 INFLUENT FLOWS AND LOADS Design Wastewater flow DWF lt 5000 gal day Monthly average value of Fats Oil and lt 30 mg L Grease FOG Monthly average value of five day lt 220 mg L Biochemical Oxygen Demand BODs Monthly average value of Total Suspended lt 150 mg L Sol
16. al served Meal served Patron seating space Vehicle space Vehicle space Employee Drain Patron minimum 500 patrons Patron Service bay Bed space Room Person Person Person Employee Bedroom Mobile home site 11 of 44 Estimated Wastewater Flow gpd 100 1 3 4 8 90 80 150 25 10 30 25 65 10 10 13 25 50 135 65 50 13 6 5 20 100 Table 4 Public Facility Wastewater Flows continued Source Nursing Rest Home Community Based Residential Facility Outdoor sport facilities toilet waste only Parks toilets waste only Parks toilets and showers Public shower facility Restaurant 24 hr dishwasher and or food waste grinder only Restaurant 24 hr kitchen waste only without dishwasher and or food waste grinder Restaurant 24 hr toilet waste Restaurant 24 hr toilet and kitchen waste without dishwasher and or food waste grinder Restaurant 24 hr toilet and kitchen waste with dishwasher and or food waste grinder Restaurant dishwasher and or food waste grinder only Restaurant kitchen waste only without dishwasher and or food waste grinder Restaurant toilet waste Restaurant toilet and kitchen waste without dishwasher and or food waste grinder Restaurant toilet and kitchen waste with dishwasher and or food waste grinder Retail store School with meals and showers School with meals or showers School without meals or sh
17. alley with bar Camp day and night Camp day use only no meals served Campground or Camping Resort Campground sanitary dump station Catch basin Church no kitchen Church with kitchen Dance hall Day care facility no meals prepared Day care facility with meal preparation Dining hall kitchen waste only without dishwasher and or food waste grinder Dining hall toilet and kitchen waste without dishwasher and or food waste grinder Dining hall toilet and kitchen waste with dishwasher and or food waste grinder Drive in restaurant all paper service with inside seating Drive in restaurant all paper service without inside seating Drive in theater Employees total all shifts Floor drain not discharging to catch basin Gas station convenience store Gas station with service bay Patron Service bay Hospital Hotel motel or tourist rooming house Medical office building Doctors nurses medical staff Office personnel Patients Migrant labor camp central bathhouse Mobile Home Manufactured home served by its own POWTS Mobile home park May be high strength waste Unit Bedroom Person 10 sq ft person Patron 10 sq ft patron Patron 10 sq ft patron Station Bowling lane Bowling lane Person Person Space with sewer connection and or service building Camping unit or RV served Basin Person Person Person 10 sq ft person Child Child Meal served Me
18. ar Bar 3 8 min dia Figure 8 Observation Pipes 12 Shape the sides with additional fill to the desired slopes 13 Place the effluent distribution lateral s as determined from the pressure distribution design on the stone aggregate Connect the lateral s using the needed connections and piping to the force main pipe from the dosing chamber Slope the piping from the lateral s to the force main pipe Lay the effluent distribution lateral s level All pipes must drain after dosing 22 of 44 VIII 14 Place stone aggregate over the distribution network and the entire distribution cell until the elevation of the stone aggregate is at least 2 inches above the top of the distribution network NOTE If using stone aggregate go to step 17 15 Install the leaching chambers and pressure distribution piping as instructed by the leaching chamber manufacturer s instructions pressure distribution design and applicable sections of ch SPS 382 83 and 84 Wis Adm Code 16 Install an observation pipe in each row of leaching chambers 17 If stone aggregate is used place geotextile fabric conforming to requirements of ch SPS 384 Wis Adm Code over the stone aggregate 18 Place cover material on the top of the geotextile fabric and extend the soil cover to the boundaries of the overall component 19 Complete final grading to divert surface water drainage away from mound Sod or seed and mulch the entire mound component
19. as determined in C 1 a Distribution cell area gal day _ gal ft day Distribution cell area ft 2 Distribution Cell Configuration a Distribution cell width s A ___ feet lt 10 ft and number of distribution cells ___ cells b Distribution cell length B Bottom area of distribution cell width of distribution cell B _ ft Distribution cell area required __ ft A B __ ft c Check Distribution Cell Length B For linear loading rate Linear Loading Rate lt Design Wastewater Flow Cell length B or effective cell length for a concave mound Linear Loading Rate lt gal day feet Linear Loading Rate lt gal ft day 27 of 44 Linear loading rate for systems with in situ soils having a soil application rate of 2 lt 0 3 gal ft day within 12 inches of fill must be less than or equal to 4 5 gal ft day Is the linear loading rate lt what is allowed __ yes ____ no If no then the length and width of the distribution cell must be changed so it does Distribution cell length B Design Wastewater Flow Maximum Linear Loading Rate Distribution cell length B _____ gal day _____ gal ft day Distribution cell length B ______ ft Distribution cell total width A ___ ft Distribution cell area ft B Distribution cell total width A ft Check percent of deflection and actual length of concave distribution cell length Percent of deflection Deflection Effective distribution cell length x 100 Percent of d
20. cation This should include the location of the reserve area if one is provided 2 Names and phone numbers of local health authority component manufacturer or POWTS service contractor to be contacted in the event of component failure or malfunction 3 Information on periodic maintenance of the component including electrical mechanical components 4 Information on limited activities on reserve area if provided E Performance monitoring must be performed on mound systems installed under this manual 1 The frequency of monitoring must be a At least once every three years following installation and b At time of problem complaint or failure 2 The minimum criteria addressed in performance monitoring of mound systems are a Type of use b Age of system Nuisance factors such as odors or user complaints gt Mechanical malfunction within the system including problems with valves or other mechanical or plumbing components e Material fatigue or failure including durability or corrosion as related to construction or structural design f Neglect or improper use such as exceeding the design rate poor maintenance of vegetative cover inappropriate cover over the mound or inappropriate activity over the mound g Installation problems such as compaction or displacement of soil improper orientation or location h Pretreatment component maintenance including dosing frequency structural integrity ground
21. d away from the system that it will not affect subsequent wastewater additions and that the effluent is ultimately treated A Minimum Soil Depth Requirements The minimum soil factors required for successful mound system performance are listed in the introduction and specification section of this package Soil evaluations must be in accordance with ch SPS 385 of the Wis Adm Code In addition soil application rates must be in accordance with ch SPS 383 of the Wis Adm Code B Other Site Considerations 1 Slopes The slope on which a mound is to be installed may not indicate the direction of groundwater movement If there is documentation that the direction of groundwater movement is different than the slope of the land the direction of groundwater movement must be considered during mound design On a crested site the fill can be situated such that the effluent can move laterally down both slopes A level site allows lateral flow in all directions but may present problems as the water table could rise higher beneath the fill in slowly permeable soils The sloping site allows the liquid to move in one direction away from the fill Figure 3 shows a cross section of a mound and the effluent movement in a slowly permeable soil on a sloping site Systems that are installed on a concave slope may have a deflection that does not exceed that allowed in Table 2 Mound components rely on lateral effluent movement through the upper soil ho
22. d height on sloping sites is calculated using Formula 10 Formula 10 Mound Height D E 2 F H Where D Sand fill depth E Down slope fill depth F Distribution cell depth H Cover material depth 2 Fill Depth The depth of fill under the distribution cell is based on the minimum depth of unsaturated soil required for treatment listed in Table 383 44 3 Wis Adm Code The minimum fill depth is 6 inches but not greater than 36 inches when the soil listed in Table 383 44 3 Wis Adm Code is 36 inches or less The minimum fill depth is 12 inches but not greater than 36 inches when the soil listed in Table 383 44 3 Wis Adm Code is greater than 36 inches A minimum unsaturated flow depth required for proper treatment of the wastewater is as required by Table 383 44 3 Wis Adm Code For sloping sites the fill depth below down slope edge of distribution cell E D slope of original grade as a decimal x width of distribution cell A 3 Distribution Cell Depth The distribution cell depth F provides wastewater storage within the distribution cell A minimum depth includes 6 inches beneath the distribution pipe and approximately 2 inches above the distribution piping as stated in the specification section of this manual This space may be provided with the use of stone aggregate or leaching chambers To calculate the minimum cell depth use Formula 11 Formula 11 Distribution cell depth F 8 inches nominal
23. dth I Fill depth at down slope edge of distribution cell E F G x horizontal gradient of side slope 3 if 3 1 x slope correction factor 100 100 3 x of slope if 3 1 18 of 44 Fill Width W Up slope width J down slope width I width of distribution cell A These calculations result in the fill material extending at least 6 inches horizontally from the top edges of the distribution cell as noted in Figure 6 Observation pipe Distribution cell 6 6 Cover material Fill material ASTM C33 fine aggregate Tilled area lt Slope A Force main Figure 6 Cross section of a Mound System 6 Basal Area The basal area is the in situ soil fill interface between the soil and the fill material Its function is to accept the effluent from the fill assist the fill in treating the effluent and transfer the effluent to the subsoil beneath the fill or laterally to the subsoil outside of the fill The soil infiltration rate of the in situ soil determines how much basal area is required When the wastewater applied to the mound has values for BOD and TSS of lt 30 mg L or if there is at least 12 inches of fill material beneath the distribution cell the soil application rates for the basal area may be those specified in Table 383 44 1 or 2 for maximum monthly average BOD and TSS of lt 30 mg L For level sites the total basal area excluding end slope area length of distribution
24. e department or governmental unit issuing the sanitary permit C Construction Procedures 1 Check the moisture content of the soil to a depth of 8 inches Smearing and compacting of wet soil will result in reducing the infiltration capacity of the soil Proper soil moisture content can be determined by rolling a soil sample between the hands If it rolls into a 1 4 inch wire the site is too wet to prepare If it crumbles site preparation can proceed If the site is too wet to prepare do not proceed until it dries 2 Lay out the fill area on the site so that the distribution cell runs perpendicular to the direction of the slope 3 Establish the original grade elevation surface contour along the up slope edge of the distribution cell This elevation is used throughout the mound construction as a reference to determine the bottom of the distribution cell lateral elevations etc and is referenced to the permanent bench mark for the project A maximum of 4 inches of sand fill may be tilled into the surface 4 Determine where the force main from the dosing chamber will connect to the distribution system in the distribution cell Place the pipe either before tilling or after placement of the fill If the force main is to be installed in the down slope area the trench for the force main may not be wider then 12 inches 5 Cut trees flush to the ground and leave stumps remove surface boulders that can be easily rolled off remove ve
25. eater then 0 3 gal ft day Formula 7 must be used to check for linear loading rate for the system when the in situ soil within 12 inches of the fill material has a soil application rate of lt 0 3 gal ft day When the in situ soil within 12 inches of the fill material has a soil application rate of lt 0 3 gal ft day the linear loading rate my not exceed 4 5 gal ft day Formula 6 Area of distribution cell A x B Where A Distribution cell width Max allowed is 10 ft B Distribution cell length Formula 7 Linear Loading Rate DWF B Where DWF Design wastewater flow B Distribution cell length 3 Concave Mound Configuration The maximum deflection of a concave distribution cell of a mound system is 10 The percent of deflection of a distribution cell is determined by dividing the amount of deflection by the effective distribution cell length of the concave distribution cell The deflection is the maximum distance between the down 14 of 44 slope edge of a concave distribution cell to the length of a perpendicular line that intersects furthest points of the contour line along the down slope edge of the distribution cell The effective distribution cell length of the concave distribution cell is the distance between the furthest points along the contour line of the down slope edge of the concave distribution cell See Figures 4 and 5 The deflection of a distribution cell on concave slopes is calculated using Formula 8
26. eflection ft ft x 100 Percent of deflection _____ lt 10 Actual distribution cell length of deflection x 0 00265 1 x effective distribution cell length Actual distribution cell length __ x 0 00265 1 x ft Actual distribution cell length ft D DESIGN OF ENTIRE MOUND AREA 1 Fill Depth a Fill depth below distribution cell At least 6 inches but not greater than 36 inches if the in situ soil beneath the tilled area is a soil listed in Table 383 44 3 Wis Adm Code that requires a minimum depth of 36 inches or less At least 12 inches but not greater than 36 inches if the in situ soil beneath the tilled area is a soil listed in Table 383 44 3 Wis Adm Code that requires a depth greater than 36 inches 1 Depth at up slope edge of distribution cell D distance required by Table 383 44 3 Wis Adm Code minus distance in inches to limiting factor D inches inches D inches at least gt 6 or 12 inches but not greater then 36 inches in accordance with Table 2 28 of 44 2 Depth at down slope edge of distribution cell E E Depth at up slope edge of distribution cell D natural slope expressed as a decimal x distribution cell width A E D natural slope expressed as decimal x A E inches X feet x 12 inches ft E inches b Distribution cell Depth for Stone Aggregate Distribution cell Distribution cell depth F for stone aggregate distribution cell amou
27. getation over 6 inches long by mowing and removing cut vegetation Prepare the site by breaking up perpendicular to the slope the top 7 8 inches so as to eliminate any surface mat that could impede the vertical flow of liquid into the in situ soil When using a moldboard plow it should have as many bottoms as possible to reduce the number of passes over the area to be tilled and minimize compaction of the subsoil Tilling with a moldboard plow is done along contours Chisel type plowing is highly recommended especially in fine textured soils Rototilling or other means that pulverize the soil is not acceptable The important point is that a rough unsmeared surface be left The sand fill will intermingle between the clods of soil which improves the infiltration rate into the natural soil Immediate application of at least 6 inches of fill material is required after tilling All vehicular traffic is prohibited on the tilled area For sites where the effluent may move laterally vehicle traffic is also prohibited for 15 ft down slope and 10 ft on both sides of 21 of 44 level sites If it rains after the tilling is completed wait until the soil dries out before continuing construction and contact the local inspector for a determination on the damage done by rainfall 6 Place the approved sand fill material around the edge of the tilled area being careful to leave adequate perimeter area not covered by the sand fill on which to place the soil
28. he following two pages may be used The inspection of the system installation and or plans is to verify that the system at least conforms to specifications listed in Tables 1 3 of this manual 42 of 44 POWTS INSPECTION REPORT ATTACH TO PERMIT Page 1 of 2 GENERAL INFORMATION State Plan ID No Tax Parcel No Property Address if Available TREATMENT COMPONENT INFORMATION SETBACKS FT TYPE MANUFACTURER CAPACITY WELL WATER BLDG VENT AND MODEL NUMBER LINE SEPTIC P DOSING id AERATION HOLDING P FILTER PUMP SIPHON INFORMATION Manufacturer Model No Demand in GPM TDH Design FORCE MAIN INFORMATION FRICTION LOSS FT Diameter Dist To Well Component Head Force Main Vert Lift Losses TDH As Built SOIL ABSORPTION COMPONENT COVER MATERIAL Cell Spacing No of Cells Manufacturer TYPE OF COMPONENT Cell Width Cell Length Cell Depth LEACHING CHAMBER OR UNIT Model No SETBACK INFO FT Property Line Well Water Line OHWM DISTRIBUTION COMPONENT Elevation data on back of form Orifice Orifice size Spacing Length Dia Spacing SOIL COVER Depth over edge of Depth of Cover Texture Seeded Sodded Mulched cell material DEVIATIONS FROM APPROVED PLAN Obs Pipes Inst amp No Header Manifold Distribution Lateral s Depth over center of cell DATE OF INST DIRECTIVE DATE OF ENFORCEMENT ORDER DA
29. ids TSS Design loading rate of fill lt 1 0 gal ft day if BOD or TSS gt 30 mg L or lt 2 0 gal ft day if BODs and TSS lt 30 mg L Design loading rate of the basal area soil application rate of effluent with maximum monthly average values of BOD and TSS of lt 30 mg L when distribution component receives effluent with a BODs and TSS of lt 30 mg L or when fill material depth is 12 inches as measured at the D dimension Volume of a single dose to absorption gt 5 times void volume of the distribution component lateral s and lt 20 of the design wastewater flow Design wastewater flow DWF from one Based on s SPS 383 43 3 4 or 5 Wis and two family dwellings Adm Code 3 of 44 Table 1 INFLUENT FLOWS AND LOADS continued Design wastewater flow DWF from 2 150 of estimated daily wastewater flow in public facilities accordance with Table 4 of this manual or s SPS 383 43 6 Wis Adm Code Linear loading rate for systems with in situ lt 4 5gal ft day soils having a soil application rate of lt 0 3 gal ft day within 12 inches of fill material Wastewater particle size lt 1 8 inch Distribution cell area per orifice lt 12 ft Table 2 SIZE AND ORIENTATION Distribution cell width A lt 10 feet gt Design wastewater flow rate design loading rate of the fill material Longest dimension parallel to surface grade contours on sloping sites Deflection of distribution cel
30. ion Service classification system of clay loams and silty clay loams that exhibit a moderate grade of structure and loams silt loams and silts with weak grades of structure or soils with weak to moderate grades of platy structure Unsaturated flow means liquid flow through a soil media under a negative pressure potential Liquids containing pathogens and pollutants come in direct contact with soil fill material microsites which enhances wastewater treatment by physical biological and chemical means Vertical Flow means the effluent flow path downward through soil or fill material which involves travel along soil surfaces or through soil pores Vertical Separation means the total depth of unsaturated soil that exists between the infiltrative surface of a distribution cell and limiting factor as by redoximorphic features groundwater or bedrock DESCRIPTION AND PRINCIPLE OF OPERATION POWTS mound component operation is a two stage process involving both wastewater treatment and dispersal Treatment is accomplished predominately by physical and biochemical processes within the fill material and in situ soil The physical characteristics of the influent wastewater influent loading rate temperature and the nature of the receiving fill material and in situ soil affect these processes Physical entrapment increased retention time and conversion of pollutants in the wastewater are important treatment objectives accomp
31. istribution cell Distribution cell area means the area within the mound where the effluent is distributed into the fill material Fill Material means sand that meets specifications of ASTM Standard C33 for fine aggregate and is used along the sides of and under the distribution cell to provide treatment of effluent Limiting Factor means high groundwater elevation or bedrock Mound means an on site wastewater treatment and dispersal component The structure contains a distribution cell area surrounded by and elevated above the original land surface by suitable fill material The fill material provides a measurable degree of wastewater treatment and allows effluent dispersal into the natural environment under various soil permeability Original Grade means that land elevation immediately prior to the construction of the mound system Parallel to surface grade contours on sloping sites means the mound is on the contour except that a 1 cross slope is allowed along the length of the mound See Ch SPS 383 Appendix A 383 44 ORIENTATION 6 6 of 44 Permeable Soil means soil with textural classifications according to the U S Department of Agriculture Natural Resource Conservation Service classification system of silt loam to gravelly medium sand Slowly Permeable Soil means soil with textural classifications according to the U S Department of Agriculture Natural Resource Conservat
32. l on concave lt 10 slopes Fill material depth at up slope edge of 26 inches when fill is placed on in situ soil distribution cell D listed in Table 383 44 3 Wis Adm Code having fecal coliform treatment capabilities of lt 36 inches or 2 12 inches but not greater than 36 inches when fill is placed on in situ soil listed in Table 383 44 3 Wis Adm Code having fecal coliform treatment capabilities of gt 36 inches 2 8 inches nominal size of distribution pipe Depth of cover material at top center of 2 12 inches Depth of cover material at top outer edge of gt 6 inches Basal area gt Design wastewater flow rate Design loading Pee l rate of basal area as specified in Table 1 Note a Letter corresponds to letters referenced in figures formulas and on worksheets 4 of 44 Table 3 OTHER SPECIFICATIONS Bottom of distribution cell Level Slope of original grade lt 25 in area of basal area of the mound Depth of in situ soil to high 2 6 inches groundwater elevation and bedrock under basal area Vertical separation between 2 Equal to depth required by s SPS 383 Table 383 44 distribution cell infiltrative surface 3 Wis Adm Code and seasonal saturation defined by redoximorphic features groundwater or bedrock Horizontal separation between 23 ft distribution cells Fill material Meets ASTM Specification C 33 for fine aggregate Cell length x Total mound width x W Cell length x
33. length B x of cells x cell width of cells 1 x cell spacing down slope width A D _ ftx Cx_ ft __ 1 x__ft __ ft ft x ft ft ft ft x ft ft 2 Level site Cell length B x total mound width W ft x ft ft 5 Determine the location of observation pipes along the length of distribution cell Observation pipes will be installed in each distribution cell so as to be representative of a cell s hydraulic performance e be located such that there are a minimum of two installed in each dispersal cell at opposite ends from one another e be located near the dispersal cell ends e beat least 6 inches from the end wall and sidewall e be installed at an elevation to view the horizontal or level infiltrative surface within the dispersal cell Observation pipes may be located less than 6 inches from end walls or side walls if specified in state approved manufacturers installation instructions 32 of 44 XI A EXAMPLE WORKSHEET SITE CONDITIONS Evaluate the site and soils report for the following e Surface water movement e Measure elevations and distances on the site so that slope contours and available areas can be determined e Description of several soil profiles where the component will be located e Determine the limiting conditions such as bedrock high groundwater level soil permeability and setbacks Slope _6 Occupancy One or Two Family Dwelling 3 _
34. length and number location and size of orifices e Manifold and force main locations with materials length and diameter of each Cross Section of System e Include tilling requirement distribution cell details percent slope side slope and cover material e Lateral elevation position of observation pipes dimensions of distribution cell and type of cover material such as geotextile fabric if applicable System Sizing e For one and two family dwellings the number of bedrooms must be included e For public buildings the sizing calculations must be included Tank And Pump or Siphon Information e All construction details for site constructed tanks e Size and manufacturer information for prefabricated tanks e Notation of pump or siphon model pump performance curve friction loss for force main and calculation for total dynamic head e Notation of high water alarm manufacturer and model number e Cross section of dose tank chamber to include storage volumes connections for piping vents and power pump off setting dosing cycle and volume high water alarm setting and storage volume above the highwater alarm and location of vent and manhole e Cross section of two compartments tanks or tanks installed in a series must include information listed above 41 of 44 B Inspections Inspection shall be made in accordance with ch 145 20 Wis Stats and s SPS 383 26 Wis Adm Code The inspection form on t
35. lished under unsaturated conditions Pathogens contained in the wastewater are eventually deactivated through filtering retention and adsorption by the fill material In addition many pollutants are converted to other chemical forms by oxidation processes Dispersal is primarily affected by the depth of the unsaturated receiving soils their hydraulic conductivity land slope and the area available for dispersal The mound consists of fill material a distribution cell and cover material Effluent is dispersed into the distribution cell where it flows through the fill material and undergoes biological chemical and physical treatment and then passes into the underlying soil for further treatment and dispersal to the environment Cover material consisting of material that provides erosion protection a barrier to excess precipitation infiltration and allows gas exchange See Figure 1 for a typical mound system The in situ soil serves in combination with the fill as treatment media and it also disperses the treated effluent 7 of 44 Cover material Distribution cell Finish grade Fill material Tilled area cer ee tank Treatment tank Figure A cross section of a mound system for POWTS IV SOIL AND SITE REQUIREMENTS Every mound design is ultimately matched to the given soil and site The design approach presented in this manual is based on criteria that all applied wastewater 1s successfully transporte
36. ng the above information the infiltrative surface area of the distribution cell area is determined by using Formula 5 Formula 5 Area DWF design loading rate of the fill material For concave systems the actual distribution cell length must be checked to determine if the cell area is sufficient See Step B 3 for further information Distribution lateral a Distribution cell Force main B Observation pipes Ee O Figure 2 Detailed plan view of a mound For location of observation pipes see IV DESIGN Step C 7 13 of 44 Observation pipe Distribution cell Fill material Tilled area Slope a situ soil ae Figure 3 Detailed cross section of a mound 2 System Configuration The distribution cell must be longer than it is wide Maximum width of the distribution cell is 10 feet The maximum length of the distribution cell is dependent on setback requirements and soil evaluation The distribution cell is aligned with its longest dimension parallel to surface grade contours on sloping sites as required by the specifications of this package so as not to concentrate the effluent into a small area as it moves laterally down slope The bottom of the distribution cell is level so one area of the distribution cell is not overloaded The dimensions for the distribution cell are calculated using Formulas 6 or 7 Formula 6 is used when the in situ soil has a soil application rate of gr
37. nt of stone aggregate below distribution laterals 6 inches min nominal pipe size of largest lateral amount of stone aggregate over distribution laterals 2 inches min F 26 inches inches 22 inches F inches c Distribution cell depth F for distribution cell with leaching chambers total height of leaching chamber F inches Cover material 1 Depth at center of distribution cell area H gt 12 inches 2 Depth at outer edges of distribution cell area G gt 6 inches 2 Mound length a End slope width K Total fill at center of distribution cell x horizontal gradient of side slope K D E 2 F H x horizontal gradient of side slope 12 inches foot K inches inches 2 inches inches x__ 12 inches ft K ft 29 of 44 b Mound length L Distribution cell length 2 x end slope width L B 2K LS ft 2x ft L feet 3 Mound width a Up slope width J Fill depth at up slope edge of distribution cell D F G x Horizontal gradient of side slope x Slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 J D F G x horizontal gradient of side slope x slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 J in in in 12 in ftx x 100 100 X or J feet b Down slope width I Fill depth at down slope edge of distribution cell E
38. on cell Distribution cell depth F for stone aggregate distribution cell amount of stone aggregate below distribution laterals 6 inches min nominal outside diameter of largest lateral amount of stone aggregate over distribution laterals 2 inches min 6 26 inches _1 5 inches _2 22 inches F 9 5 inches c Distribution cell depth F for distribution cell with leaching chambers total height of leaching chamber F inches d Cover material 1 Depth at distribution cell center H 2 12 inches 2 Depth at distribution cell edges G 2 6 inches 2 Mound length a End slope width K Total fill at center of distribution cell x horizontal gradient of side slope K D E 2 F H x horizontal gradient of side slope 12 inches foot K _L1_ inches _14 25 inches 2 _9 5 inches _12 inches x_3 12 inches ft K 8 53 or 8 5 ft 36 of 44 b Mound length L Distribution cell length 2 x end slope width L B 2K L _100 ft 2x 8 5 ft L 117 feet 3 Mound width a Upslope width J Fill depth at up slope edge of distribution cell D F G x Horizontal gradient of side slope x Slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 J D F G x horizontal gradient of side slope x Slope correction factor 100 100 gradient of side slope x of slope or value from Table 5 J _11 in _9 5_in _6 in 12in ftx_3 x 100 100 3 x_6 Jor __
39. ope is maintained multiply the calculated width by the correction factor found by using the following equations or the correction factor listed in Table 5 Up slope correction factor 100 100 3 x of slope Down slope correction factor 100 100 3 x of slope 17 of 44 Table 5 Down slope and up slope width correction factors Slope Down slope Up Slope correction correction factor factor 0 1 00 1 00 1 1 03 0 97 2 1 06 0 94 3 1 10 0 915 4 1 14 0 89 5 1 18 0 875 6 1 22 0 85 7 1 27 0 83 8 1 32 0 81 9 1 37 0 79 10 1 43 0 77 11 1 49 0 75 12 1 56 0 735 13 1 64 0 72 14 1 72 0 705 15 1 82 0 69 16 1 92 0 675 17 2 04 0 66 18 2 17 0 65 19 2 33 0 64 20 2 50 0 625 21 2 70 0 61 22 2 94 0 60 23 3 23 0 59 24 3 57 0 58 25 4 00 0 57 The most critical dimensions of the fill are fill depths D amp E distribution cell length B distribution cell width A and the down slope width I End slope width K Total fill at center of distribution cell D E 2 F H x horizontal gradient of selected side slope 3 if 3 1 side slope Fill Length L Distribution cell length B 2 x end slope width K Up slope width J Fill depth at up slope edge of distribution cell D F G x horizontal gradient of side slope 3 if 3 1 x slope correction factor 100 100 3 x of slope if 3 1 Down slope wi
40. orrectly it is important to develop plans that will be used to install the system correctly the first time The following checklist may be used when preparing plans for review The checklist is intended to be a general guide Not all needed information may be included in this list Some of the information may not be required to be submitted due to the design of the system Conformance to the list is not a guarantee of plan approval Additional information may be needed or requested to address unusual or unique characteristics of a particular project Contact the reviewing agent for specific plan submittal requirements which the agency may require that are different than the list included in this manual General Submittal Information e Photocopies of soil report forms plans and other documents are acceptable However an original signature is required on certain documents e Submittal of additional information requested during plan review or questions concerning a specific plan must be referenced to the Plan Identification indicator assigned to that plan by the reviewing agency e Plans or documents must be permanent copies or originals Forms and Fees e Application form for submittal provided by reviewing agency along with proper fees set by reviewing agent Soils Information e Complete Soils and Site Evaluation Report form SBD 8330 for each soil boring described signed and dated by a certified soil tester with license number
41. owers Self service laundry toilet waste only Self service laundry with only residential clothes washers Swimming pool bathhouse May be high strength waste Unit Bed space Patron Patron 75 patrons acre Patron 75 patrons acre Shower taken Patron seating space Patron seating space Patron seating space Patron seating space Patron seating space Patron seating space Patron seating space Patron seating space Patron seating space Patron seating space Patron 70 of total retail area 30 sq ft per patron Classroom 25 students classroom Classroom 25 students classroom Classroom 25 students classroom Clothes washer Clothes washer Patron 12 of 44 Estimated Wastewater Flow gpd 65 3 5 3 5 6 5 10 4 12 28 40 44 500 400 300 33 200 6 5 Step B Design of the Distribution Cell This section determines the required infiltrative surface area of the distribution cell fill interface as well as the dimensions of the distribution network within the fill 1 Sizing the Distribution Cell The minimum bottom area of the distribution cell is determined by dividing the design wastewater flow per day by the design loading rate of the fill material As specified in Table 1 the design loading rate of the infiltration surface of the distribution cell is lt 1 0 gal ft day if BODs or TSS gt 30 mg L or lt 2 0 gal ft day if BOD or TSS lt 30 mg L Usi
42. pipe size of distribution lateral 16 of 44 4 Cover Material The cover material G amp H provides frost protection and a suitable growth medium for vegetation For design purposes use a depth of 12 inches above the center of the distribution cell H and 6 inches above the outer edge of the distribution cell G Cover material depth at distribution cell center H gt 12 inches Cover material depth at distribution cell edges G 2 6 inches 5 Fill Length and Width The length and width of the fill are dependent upon the length and width of the distribution cell fill depth and side slopes of the fill Side slopes may not be steeper than 3 1 over the basal area 1 e 3 feet of run to every 1 foot of rise Soil having textures other than those specified for the fill media may be used to make the slopes gentler than the required 3 1 slopes once the 3 1 slope exists with the fill material The distribution cell length is generally perpendicular to the direction of slope so the effluent is spread out along the contour The fill length consists of the end slopes K and the distribution cell length B The fill width consists of the up slope width J the distribution cell width A and the down slope width I On sloping sites the up slope width J is less while the down slope width I is greater than on a level site to maintain the 3 1 side slope see Fig 2 To calculate the up slope and down slope widths when a 3 1 side sl
43. rizons Lateral movement becomes more important as soil permeability decreases Mound location In open areas exposure to sun and wind increases the assistance of evaporation and transpiration in the dispersal of the wastewater Sites with trees and large boulders Generally sites with large trees numerous smaller trees or large boulders are less desirable for installing a mound system because of difficulty in preparing the surface and the reduced infiltration area beneath the mound Areas that are 8 of 44 VI occupied with rock fragments tree roots stumps and boulders reduce the amount of soil available for proper treatment If no other site is available trees in the basal area of the mound must be cut off at ground level A larger fill area is necessary when any of the above conditions are encountered to provide sufficient infiltrative area 4 Setback distances The setbacks specified in ch SPS 383 Wis Adm Code for soil subsurface treatment dispersal component apply to mound systems The distances are measured from the up slope and end slope edge of the distribution cell and from the down slope toe of the mound See also setback distances from toe of mound system to wells in s NR 812 08 Table A FILL AND COVER MATERIAL Fill Material The fill material and its placement are one of the most important components of the mound system Quality control of the fill material is critical to system performance each tr
44. rooms Public Facility _____ gal day Estimated wastewater flow Depth to limiting factor _____ inches Minimum depth of unsaturated soil required by Table 383 44 3 Wis Adm Code ___ inches Soil application rate of in situ soil used _____ gal f day FOG value of effluent applied to component ____ mg L BOD value of effluent applied to component _____ mg L TSS value of effluent applied to component ____ mg L Fecal Coliform monthly geometric mean value of effluent applied to component gt 10 cfu 100ml _Yes_ No Type of distribution cell __ Stone aggregate or __ Leaching chamber B DESIGN WASTEWATER FLOW DWF One or Two family Dwelling Combined wastewater flow DWE 150 gal day bedroom x of bedrooms 150 gal day bedroomx______ Fof bedrooms gal day Clearwater and graywater only DWE 90 gal day bedroom x of bedrooms 90 gal day bedroom x _____ F of bedrooms gal day 26 of 44 Blackwater only DWE 60 gal day bedroom x of bedrooms 60 gal day bedroom x of bedrooms gal day Public Facilities DWE Estimated wastewater flow x 1 5 gal day x 1 5 gal day C DESIGN OF THE DISTRIBUTION CELL 1 Total size of the Distribution Cell s area a Loading rate of fill material ___ lt 1 0 gal ft day if BOD or TSS gt 30 mg L or ___ 2 0 gal ft day if BOD or TSS lt 30 mg L b Bottom area of total distribution cell area Design wastewater flow loading rate of fill
45. sal area required lt Basal area available 1500 ft lt 1400 ft The available basal area must be increased by 100 ft This can be accomplished by increasing the down slope width I by 1 ft making it 10 5 ft See d for recalculation of basal area 38 of 44 d Basal area available recalculation of basal area 1 Sloping site Cell length B x of cells x cell width of cells 1 x cell spacing down slope width A D 100 ft x 1 x 4 5 ft 1 1 x O ft 10 5 ft 100 ft x 4 5 ft 0 ft 10 5 ft 10 ftx 15 ft 1500 ft 2 Level site Cell length B x total mound width W ft x ft ft 5 Determine the location of observation pipes along the length of distribution cell Observation pipes will be installed in each distribution cell so as to be representative of a cell s hydraulic performance e be located such that there are a minimum of two installed in each dispersal cell at opposite ends from one another e be located near the dispersal cell ends e beat least 6 inches from the end wall and sidewall e be installed at an elevation to view the horizontal or level infiltrative surface within the dispersal cell Observation pipes may be located less than 6 inches from end walls or side walls if specified in state approved manufacturers installation instructions 39 of 44 XII PLAN SUBMITTAL AND INSTALLATION INSPECTION A Plan Submittal In order to install a system c
46. stallation instructions Maximum final slope of mound lt 3 1 surface Note a Letter corresponds to letters referenced in figures formulas and on worksheets 5 of 44 Il Table 3 OTHER SPECIFICATIONS continued Cover material Soil that will provide frost protection prevent erosion and excess precipitation or runoff infiltration and allow air to enter the distribution cell Grading of surrounding area Graded to divert surface water around mound system Limited activities Unless otherwise specifically allowed in this manual vehicular traffic excavation and soil compaction are prohibited in the basal area and 15 feet down slope of basal area if there is a restrictive horizon that negatively affects treatment or dispersal In accordance with ch SPS 383 Wis Adm Code In accordance with ch SPS 383 Wis Adm Code and this manual DEFINITIONS Definitions not found in this section are located in ch SPS 381 of the Wisconsin Administrative Code or the terms use the standard dictionary definition Basal Area means the effective in situ soil surface area available for infiltration of partially treated effluent from the fill material Deflection of distribution cell means the ratio between the maximum distance between the down slope edge of a concave distribution cell to the length of a perpendicular line that intersects the furthest points of the contour line along the down slope edge of the d
47. stribution cell length x 100 Percent of deflection ft ft x 100 Percent of deflection _____ lt 10 Actual distribution cell length of deflection x 0 00265 1 x effective distribution cell length Actual distribution cell length __ x 0 00265 1 x ft Actual distribution cell length ft D DESIGN OF ENTIRE MOUND AREA 1 Fill Depth a Minimum fill depth below distribution cell At least 6 inches but not greater than 36 inches if the in situ soil beneath the tilled area is a soil listed in Table 383 44 3 Wis Adm Code that requires a minimum depth of 36 inches or less At least 12 inches but not greater than 36 inches if the in situ soil beneath the tilled area is a soil listed in Table 383 44 3 Wis Adm Code that requires a depth greater than 36 inches 1 Depth at up slope edge of distribution cell D distance required by Table 383 44 3 Wis Adm Code minus distance in inches to limiting factor D 36 inches 25 inches D _11_ inches at least gt 6 or 12 inches but not greater than 36 inches in accordance with Table 2 35 of 44 2 Depth at down slope edge of distribution cell E E Depth at up slope edge of distribution cell D natural slope expressed as a decimal x distribution cell width A E D natural slope expressed as decimal x A E _11 inches _0 06 x 4 5 feet x 12 inches ft E 14 24 or 14 25 inches b Distribution cell Depth for Stone Aggregate Distributi
48. tal or level infiltrative surface within the dispersal cell Observation pipes may be located less than 6 inches from end walls or side walls if specified in state approved manufacturers installation instructions Step D Distribution Network and Dosing System A pressurized distribution network based on a method of sizing as described in either Small Scale Waste Management Project publication 9 6 entitled Design of Pressure Distribution Networks for Septic Tank Soil Absorption Systems or Dept of Commerce publications SBD 10573 P or SBD 10706 P entitled Pressure Distribution Component Manual for Private Onsite Wastewater Treatment Systems is acceptable 20 of 44 VII SITE PREPARATION AND CONSTRUCTION Procedures used in the construction of a mound system are just as critical as the design of the system A good design with poor construction results in system failure It is emphasized that the soil only be tilled when it is not frozen and the moisture content is low to avoid compaction and puddling The construction plan to be followed includes A Equipment Proper equipment is essential Track type tractors or other equipment that will not compact the mound area or the down slope area are required B Sanitary Permit Prior to the construction of the system a sanitary permit obtained for the installation must be posted in a clearly visible location on the site Arrangements for inspection s must also be made with th
49. uckload of material must meet specifications for the fill Determining whether a proposed fill material is suitable or not requires that a textural analysis be performed The standard method to be used for performing this analysis conforms to ASTM C 136 Method for Sieve Analysis of Fine and Coarse Aggregates and ASTM E 11 Specifications for Wire Cloth Sieves for Testing Purposes Annual Book of ASTM Standards Volume 04 02 Information concerning these methods can also be obtained from Methods of Soils Analysis Part 1 C A Black ed ASA Monograph 9 American Society of Agronomy Inc 1975 Cover material The cover material is a soil that will allow air exchange while promoting plant growth The gas exchange will increase the treatment performance of the system by providing oxygen to the wastewater to help ensure aerobic conditions in the mound system The plant growth will provide frost protection in the winter season Clays may not be used for cover material as they will restrict oxygen transfer Often excavated soil from the site can be used Seeding or other means must be done to prevent erosion of the mound DESIGN Location Size and Shape Placement sizing and shaping of the mound and the distribution cell within the mound must be in accordance with this manual The means of pressurizing the distribution network must provide equal distribution of the wastewater A pressurized distribution network using a method of
50. water intrusion or improper sizing i Dose chamber maintenance including improper maintenance infiltration structural problems or improper sizing j Distribution piping network including improper maintenance or improper sizing k Ponding in distribution cell prior to the pump cycle is evidence of development of a clogging mat or reduced infiltration rates l Siphon or pump malfunction including dosing volume problems pressurization problems breakdown burnout or cycling problems m Overflow seepage problems as shown by evident or confirmed sewage effluent including backup if due to clogging 24 of 44 4 Reports are to be submitted in accordance with ch SPS 383 Wis Adm Code IX REFERENCES Wisconsin Mound Soil Absorption System Siting Design and Construction Converse J C and E J Tyler Publication 15 22 Small Scale Waste Management Project 1 Agriculture Hall University of Wisconsin Madison WI 25 of 44 X A MOUND WORKSHEET SITE CONDITIONS Evaluate the site and soils report for the following e Surface water movement e Measure elevations and distances on the site so that slope contours and available areas can be determined e Description of several soil profiles where the component will be located e Determine the limiting conditions such as bedrock high groundwater level soil application rates and setbacks Slope ___ Occupancy One or Two Family Dwelling ____ of bed
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