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HomeMy WebLinkAbout1978-06-07 Septic System DesignJune 7, 1978 Mr. Lester Kelly 125 South Brown Road Long Lake, Minnesota 55356 Res Percolation Tests for Subdivision Platting, Orono, Minnesota Job Number 11-76-25 Dear Mr. Kellys Enalosed is information requested in regards to -the suitability of Parcels 2 and 3 for on-site sewage treatment. The drainfield information is based on percolation tests and soil borings performed on May 23, 24, and 25, 1978, Parcel 2 The soils found on Parcel 2 are Glencoe silty clay loam, Hamel loam and Lester loam. These soils are mapped in Figure 1. the percola- tion rate for the primary field as tested was 9.7 minutes/inch. The percolation rate for the secondary field as tested was 7.3 minutes/ the proposed drainfield areas are indicated in Figure 1. Percolation rates and depths to the water table are shown in Table 1. The soil logs of the soil borings are shown in Table 2. An 'innovative shallow trench systwm" or a mound system ed for both the primary and secondary drainfield sites. toms will allow for the required 3.0' separation between of the drainfield and the water table. The soil borings the primary and secondary drainfield sites indicate that table is at a lepth )f 4.0' or greater. I have enclosed tion view of such a system. Parcel 3 is recommend - These sys- the bottom taken at the water an eleva- `The soils found on Parcel 3 are Glencoe silty clay loam, Hanel loan and Lester loam. These soils are mapped in Figure 1. The percola- tion rate for the primary field as tested was 6.5 minutes/inch. The percolation rate for the secondary field as tested was 11.5 minutes/ inch. The location 3f the percolation rest holes, soil borings, and proposed drainfield areas are indicated in Figure 1. Percolation rates and depths to the water table are shown in Table 1. The soil loqs of the soil borings are shown in Table 2. l.0 June 7, 1978 Mr, Lester Kelly Page Two A conventional septic system is recommended for the primary drain - field site provided that a 3' verticle separation is maintained be- tween the bottom of the drainfield trenches and the water table. The soil borings taken at the primary drainfield site indicate that the water table is at a depth of -5.1' or greater. An 'innovative shallow trench system' is recommended for the sec- ondary site. This system will allow for the required 3.0' "parti- tion between the bottom of the drainfield and the water table. Soil borings indicated that the depth to the water table is 4.0' or greater. If you have any questions, please do not hesitate to contact me. Sincerely, EUGENE A. HICKOK & ASSOCIATES James P. DeBene,4et, P.S. Enclosures 6t,5 Mow e,,Ils o a4 P'Ica5 ti �- g � c�-IUe� o � 8 SI t.1Y G,P'f o� \4 �Up.f1 \ X133�� + S+ 44 )(,SOIL P,aRaNl, LES KEL -T, EA. HKXM i ASSOCIATIES PEZoLATq►J -TEST +iQl, ISIS - FIB WEEKS LAC,-TIoO t SaLS r1w. �WMIS-IMw1 WMA JANE mll� FIL-ua 0 TABLE 1 PERCOLATION RATES AND DEPTH TO WATER TABLE PARCEL 2 - (no lot) Percolation rate of the primary field (holes 1, 2, 5, 6) - 9.7 min/inch Percolation rate of the secondary field (2, 3, 4, 5) = 7.3 thin/inch *See soil logs of soil bcring. PARCEL 3 - Percolation Rate Depth to Hole Material Minutes/Inch Water Table 1 Fine sandy clay 21.8 - 2 Clayey sand 5.0 - 3 Clayey sand 8.8 - 4 Clayey sand 8.3 - 5 Clayey sand 8.6 - 6 Fine sandy clay 20.0 - Sbl * - 5.5' (mottling at 4.0' Sb2 * - 6.0'(mottling at 5.0' Sb3 - 5.01(mottling at 4.0' Percolation rate of the primary field (holes 1, 2, 5, 6) - 9.7 min/inch Percolation rate of the secondary field (2, 3, 4, 5) = 7.3 thin/inch *See soil logs of soil bcring. PARCEL 3 - Percolation Rate Hole Material Minutes/Inch I clayey lana 3.7 2 Clayey sand 7.3 3 Clayey sand 10.0 4 Clayey sand 10.9 5 Fine sandy clay 43.5 6 Clayey sand 5.5 Sbl * - Sb2 * - Sb3 * - Depth to Water gable Greater than 8.0' (mottling at 6.5') 7.01(mottling at 5.1' 4.0 (mottling at 4.5' Percolation rate of the primary field (holes 1, 2, 5, 6) = 6.5 min/inch Percolation rate of the secondary field (2, 3, 4, 3) = 11.5 min/inch *See soil logs of soil boring. TABLE 2 SOIL LOGS PARCEL 2 - SOIL BORING NO. 1 Depth (feet) Material 0.0 - 0.5 Dark gray sandy loam 0.5 - 2.1 Dark brown sandy clay 2.1 - 4,1' Brown clayey sand 4.0 - 6.0 Brown sandy clay, 6.0 - 8.0 mottled 6.0 - 8.0 Yellow brown silty Water table clay, mottled Water table encountered at -5.5' SOIL BORING NO. 3 Depth ( feet) 0.0 - 1.0 1.0 - 4.0 4.0 - 4.8 4.8 - 8.0 Material SOIL BORING NO. 2 Depth (feet) Material 0.0 - 1.0 Dark gray sandy loam 1.0 - 2.2 Dark brown sandy clay 2.2 - 3.8 Yellow brown clayey sand 3.8 - 8.0 Yellow brown silty clay, mottling at -5.0 Water table encountered at -6.0' Black sandy loam Reddish brown fine sandy clay Brown sandy clay, mottling at -4.0' Yellow brown silty clay Water table encountered at -5.0'. PARCEL 3 - SOIL BORING NO. 1 Depth (feet) Material 0.0 - 1.0 Brown sandy loam 1.0 - 2.0 Yellow brown sandy clay 2.0 - 6.0 Yellow brown clayey cla 4.5 sand 6.0 - 8.0 Yellow brown silty clay, mottling at -6.5' Water table not encountered within 8.0' of surfaces. SOIL BORING NO. 3 Depth (feet) Material 0.0 - 0.5 Brown sandy loam 0.5 - 1.0 Brown silty clay loam 1.0 - 3.0 Yellow brown silty clay Water table encountered it -4.01. SOIL BORING NO. 2 Depth (feet) 0.0 - 0.5 0.5 - 1.0 1.0 - 3.5 3.5 - 7.0 7.0 - 8.0 Material Brown sandy loam Brown silty clay loam Yellow brown silty clay, calcareous material Yellow brown sandy clay, mottling at -5.1 Yelljw brcwn silty cla Water Gable encu-ntered at -7.0' Depth (feet) Material 3.0 - 3.5 Yellow brol y cla 3.5 - 4.5 Yellow brows. .,-y cla 4.5 - 6.0 Mellow brown sandy c.ay, mottling at -4.5 6.0 - 8.0 Yel.ovl brown silty cla SPECIFICATIONS FOR PROPOSED ON-SITE DISPOSAL SYSTEM CONVENTIONAL SYSTEM: DISTRIBUTION THROUGH GRAVITY FLOW LOCATION: Greg Mack 105 South Brown Road Orono, Minnesota Lot 2, Block 2, Kelley Green Subdivision DATE: August, 1986 I. SEWAGE TANK - TWO 1,000 - gallon 1.10010 CAPACIfY tanks, IN SERIES, manufactured and installed in compliance with the following specifications. See Fiqurp 1 for location. 1. MATERIA�S A. General All tanks, regard iess c)t na`orial or method of constru.- tion shall be: 1. Water t iglit 2. So designed and constructed as to withstand all lateral -arch pressures under saturated soil conditions with the tank empty. 3. So designed and constructed as to withstand a minimum of seven feet of saturated earth cover above the tank top. Ir. addition, the following specifications apply to specific materials as indicated. B. Precast Concrete Tanks 1. Precast concrete tanks shall be constructed of at least a 4,000 psi (pounds per square inch) core test, air entrained concrete miK. 2. Precast concrete tanks shall be cured to at least a seven-day strength before installation. C. Fiberglass and Plastic Tanks Fiberglass and plastic tanks shall he designed and constructed to meet the requirements in Section I -A. D. Metal Tanks Metal tanks shall have a wall thickness of at least eight gauge corrosion resistant alloys and shall be coated inside and out with at least one coat of bitumastic seal, Koppers 300-M, or by ether approved equivalent means. Tanks shall be carefully installed so as not to puncture or damage the seal coating, E. Block or Sectional Tanks 1. Rectangular Blocks a. Rectangular blocks shall be laid on an approved bottom. Block shall be at least eight inches thick, constructed of a 4 000 psi core test concrete mix, and cured to a 28 -day strength before installation. b. Rectangular blocks shall be laid either with mortar joints or filled cores. c. There shall be at least two coats of 1/4 inch thick concrete plaster placed on the inside of the block tank. There shall be at least two hours elapsed time between coats. The plaster coat shall start at the bottom course and work up. 2. Circular Block Tanks a. Circular blocks shall be carefully placed oar an approved bottom. Circular blocks shall be at frost two inches thick and constructed of a 4,000 psi core test concrete mix, cured to a 28 -day strength before installation. b. There shall be at least two coats of 1/4 inch thick concrete plaster placed on the inside of the block tank. There shall be at least two hours elapsed time between Coats. The plaster- coat shall start at the bottom course and work up. 3. Sectional Tanks a. A sectional tank shall have an entire section cast as an integral unit. b. A sectional tank shall have two oc more sections and shall have at least one joint below the level of the outlet invert of the tank. c. Sectional tanks shall have an irtegrally cast bottom, or shall be laid on an approved bottom. d. The joint or joints shall be permanently sealed so as to be watertight. 4. Bottom: a. Any tank not having an integrally cast bottom shall not be installed when the water table is closer than twelve inches to the bottom of tht excavation. b. 1f the bottom is poured -in-place concrete, it shall be at least four inches thick and extend to at least four inches outside the tank wall. A concrete mix of at least one part cement, two parts washed sand and three parts washed rock shall be mixed before placement in the excavation. c. If a starter ring is used, it shall be constructed of a 4,000 psi core test concrete mix, cured to a seven-day strength before installation. It shall extend at least one inch beyond the tank wall, inside and out. A bottom shall be poured of concrete mix defined in Section (b) above. It shall extend at least two inches above the starter ring and shall be at least four inches thick. d. If a precast bottom is used, it shall be made of a 4,000 psi core test concrete mix, cured to a seven-day strength before installation. It shall extent at least one inch beyond the tank wall, or be cast integrally with the bottom section. e. A sectional tank not having an integrally precast bottom shall have a four -inch thick bottom poured within the tank wall. 5. Covers a. Any tank cover not integrally cast with the tank shall be so installed that the joint witn the tank sidewall is permanently sealed so as to be watertight. b. All covers shall be so designed and constructed as to withstand a minimum of seven feet of saturated earth cover above the tank top. F. Inlet and Outlet Device Materials 1. Inlet and outlet devices shall be sanitary tett), or baffles constructed of acid resistant concrete, acid resistant fiberglass or plastic. 2. Sanitary tees shall be glued to the inlet or outlet pipes. Baffles shall be integrally cast with :he tank, affixed with a permanent waterproof adhesive or affixed w?th stainless steel connectors, top and bottom. 2. DESIGN All tanks, regardless of material or method of construction, shall conform to the followinq design criteria: A. The 11QUI) DEPTH Of any septic tank or compartment thereof shall be not less than 3U inches. A liquid depth greater than six and one-half feet shall not be considered in determining tank capacity. B. No tank or compartment thereof shall have an inside horizontal dimension less than 24 inches. C. Inlet and outlet connections of the tank thereof shall be submerged by means of vented, sanitary tees of baffled. 0. The space in the tank between the liquid surface and the top of the inlet and outlet baffles or sanitary tees shall oe not less than 20 percent of the total required liquid capacity, except that in horizontal cylindrical tanks this space shall be not less than 15 perctart of the total required liquid capacity. E. The inlet baffle or sanitary tee shall extend at least six inches but not more than 20 percent of the total liquid depth below the liquid surface and at least one inch above the crown of the inlet sewer. F. The outlet baffle or sanitary tee and the baffles or sanitary tees between compartments shall extend below the liquid surface a distance equal to 40 percent of the liquid depth except that the penetration of the indicated baffles or sanitary tees for horizontal cylindrical tanks shall be 35 percent of the total liquid depth. They also shall extend above the liquid surface as required in 0 above. In no case shall they extend less than six inches above the liquid surface. G. There shall be at least one inch between the underside of the top of the tank and the highest point of the inlet and outlet devices. H. The inlet invert shall be not less than three inches above the outlet invert. 1. The inlet and outlet shall be located opposite each other along the axis of maximum dimension. The horizontal distance between the nearest points of the inlet and outlet devices shall be at least four feet. J. Sewage tanks shall be set back the following distance from the features given below: Feature Minimum Setbank Uistancts (feet) Water Supply Well and Bur ed — 56 Water Suction Pipe 3uried Pipe Distributing 10' Water Under Pressure Eui ldings 10' ?.O Property Lines 10' The Ordinary High Water Mark of: Natural Environment Lakes 1SID'* and Rivers Recreational Development 750* Lakes and Rivers General Development Lakes 500* and Streams Wild River 1501* Scenic River 1001* Designated Tributaries of 751* Wild, Scenic, and Recreational Rivers Wetlands 751 PgiFFC00eo *Required for new development and where practicable, for existing developments. r 3. SURFACE FLOODING Sewage tanks shall not be placed in flood plain delineated by local ordinances adopted in compliance with the Statewide Standards for Mana ement of Flood Plain Areas of Minnesota (Minn. Reg. NR - , or in areas for which reg ona Information is available from the Department of Natural Resources, except that in areas where ten-year flood information is available from and/or approved by the Department of Natural Resources. II. DISTRIBUTION OF EFFLUENT 1. BY GRAVITY FLOW OVER THE SOIL TREATMENT AREA A. Level Ground Wi%rre the elevation difference of the ground surface does not exceed P inches in any dire(�.Ion within the soil treatment area, the sewage tank of uent may be directed to the soil treatment area through a distribution box. See Detail). Oistriuution boxes may not be allowed by certain governing bodies or municipalities. Contractor shall contact appropriate authorities for such determination. 1. The box shall be watertight with a removabl- cover- and shall be constructed of durable materials not subject to excessive= rorr-osion or decay. The minimum insi-ie� dimension be at: least ton int:ht- 2. The inverts of all outlet Shall be at the - n.- -1evttion as measured from a Iiqui,' surtacN in the bottom of the box. 1 3. Thz inlet invert shall be at least one inch above tht• outlet inverts. 4. The cutlet inverts shall be at least four rr.ches above thr distribution box f Ioor-. b. Each drainfield trench- line shall be connected separately to the distribution box and ;hall no' be subdivided. .then sewage tank'effluent rs delivered to the distribution box by pump, either a baff t wall shall be, in;'.alled in the distribution box or the pump discharge s 11 be directed against a wall or- side of the box on which there is no out t. The baffle shall be secured to the borc,and shall extend at least inch above the crown of the inlet flow line �\ B. Sloping Ground (AS r 1>0"P 9 OXcs Where the elevatrnn difference of the ground surface exceeds 28 inches in any direction within soil trcitment arta a drop box shall be installed at the head end of each literal line. Connections between drop boxes shall be by watertight pipes. (See Detail). 1. The drop box shall be watertight and constructed of durable materials not subject to excessive corrosion or decay. The minimum inside dimension shall be at lea3t ten inches, unless the box is to be used as a valve box. Then each outlet shall have at least eight inches of sidewall space and the side of any outlet shall be at least six inches from any corner. 2. The invert of the inlet pipe shall be at least one inch higher than the invert of the outlet pipe to the next trench. 3. The invert of the outlet pipe to the next trench shall be at least two inches higher than the invert of the outlet pipe of the trench in which the box is located. 4. When sewage tank effluent is delivered to the drop box by a pump, the pump discharge shall be directed against a wall or side of the box on which there is no outlet. S. The drop box shall have a removable cover either flush or above finished grade or covered by no more than six inches of soil. III. GRAINFIELD Final treatment and disposal of all sewage tank effluent shall be by means of soil treatment. 1. SIZING ✓" Indicated average percolation rates is 6.5 minutes per inch for the primary site. ✓ A. Total drainfield area is 762 ft2 (Required soil treatment area based on a 4 -bedroom Type 1 house). B. Drainfield trench bottom width is 3' C. Total lineal feet of drain tile is 2541.' D. See detail for typical placement. 11-11 E. Minimum spacing of laterals is 7.5 feet from rentor to center. 2. LOCATION A. On slopes in excess of 1? percent the soil profile shall be carefully evaluated in the location of the proposed soil treatment area and downslope to identify the presence of layers that may cause sidehill seepage. In no case shall a trench he located within 15 feet of such a layer surfacing on the downslope. B. Bed construction shall be limited to areas having natural slopes of less than six percent. C. Any soil treatment area other than seepage pits shall be set, bick the following distances from the features given below: Set back distance Feature in feet Any other water supply well or buried 75' water suction pipe Buried pipe distributing water under pressure l.0' Buildings 20' Property lines 10' Feature The ordinary High Water Mark of: Natural Environment Lakes and Streams Recreational Development Lakes and Rivers mineral Development Lakes and Streams Wild River Scenic River Set back distance in feet 150'* 75'* 501 * 150'* 100'* Designated Tributaries of Wild, Scenic, and 75' Recreational Rivers Wetlands lbI * Required for new developments and where practicable, for eAisting developments. 3. DESIGN AND CONSTRUCTION A. The bottom of trenches and beds shall be .it �hiroe feet above the seasonal high water table or bedrick. B. the bottom of the trench or bed excavation shall be level. The bottom and sides of th- trench or bed excavation to the level of the top of the filter material sr,.,l be scarified to remove smears left by the construction equipment an footprints. All loose material shall be removed from the excavation. The bottom of the excavation shall not be driven on or walked on after scarification. C. When the Soil perculjtion rate at the bottom of the trench or bpd is slower than 15 minutes per inch, no vehicle or excavation equipment shall be allowed on the trench or bed area. Excavation shall be by back hoe or other means that allow the equipment wheels or tracks to remain on the surface soil. D. There shall be a layer of 6 inches of filter material in the bottom of the trenches and beds placed as shown on the detail. Trenches closer than 10 feet to trees, 6 inches or larger, shall have 12 inches of filter material in the bottom of the trench beneath the distribution pipe. E. Distribution pipe used in trenches or beds for gravity flow distribution shall be at least four inches in diameter and constructea of sound and durable materials not subject to corrosion or decay or to loss of strenqth under continuo-isly wet conditions. The ends of each lateral shall be capped. 1. Agricultural drain tile shall be in 12-inch lengths and laid with 1/4-inch open joints on grade boards. All open joints shall be protected on top by strips of asphalt-treated building paper at least ten inches long and three to six inches wide or by other acceptable approved means. 2. Perforated plastic pipe shall be laid with one row of perforations on the bottom. Perforations shall be at least 1/2-inch in diameter and spaced no farther than 12 inches apart. 3. Other devices may be used to distribute sews -ank effluent over the soil treatment area upon approval of the local ai­,istrator of the sanitary ordinance. 4. The distribution pipes shall be laid level or on a uniform slope away from the sewage tank of no more than four inches per 100 feet. F. The filter materials shall be covered with untreated building paper or a two-inch layer of hay or straw or similar, approved permeable me-:erials. G. The trenches or beds shall be backfilled with the excavated ma.. :aa and slightly crowned above finished grade to allow for settling. oackfill shall not be compacted to a density greater than that of the original scil. H. The minimum depth of cover over the distribution pipes shall be at least eight inches. I. The maximum length of any drainfield trench shall be no more than 100 feet. J. The maximum depth of cover over the distribution pipes shall be no more than 36 inches and preferably 24 inches. K. A grass cover shall be established over the soil treatment area. L. Bottom of trenches shall be no more than "4 inches below existing ground. Season,;l high water table was noted at a depth of 5.1 feet. M. See Details for further details. INSULATED VENT PI PE LOCATE THE SEPTIC TANK NEAR THE MAIN SOURCE OF SEWAGE 'w CLEAN OUT - „ 6 TO 121@ OF EARTH COVER T� SOIL O CLOSER ` � " TREA LN TMENT THAN 10' UNIT DETAIL 1 VERTICAL SIDEWALL SEPTIC TANK FINISHED GRADE AT LEAST K 6" TO 12" SOIL COVER AT LEAST I" 4„DIA. 4” DIA.— MI AT LEAST I" AT LEAST I" 7 -y7t� A 8 i —AT LEAST 3" DIMENSIONS FOR TANKS WITH VERTICAL SIDES WIDTH W 24" MINIMUM LENGTH L 2 TO 3 TIMES THE WIDTH DIAMETER 60" MINIMUM DEPTH, D 30" MINIMUM; 78" MAXIMUM A 0.2 D 8 6" MINIMUM; 0.2 D MAXIMUM C 10.4 D T A C l 6 of — AT LEAST 4 FEET ----I NOTES: 1. SANITARY TEES AT LEAS"P 4 INCHES IN DIAMETER 4. MANHOLE COVERS SHALL BE LOCATED WITHIN MAY BE USED IN PLACE OF BAFFLES. 12 INCHES BUT NO CLOSER THAN 6 INCHES 2. THERE SHALL BE ONE OR MORE MANHOLES, 20" BELOW FINISHED GRADE AND COVERED WITH AT LEAST DIMENSION AND LOCATED WITHIN 6 FEET LEAST 6 INCHES OF EARTH. OF ALL TANK WALLS. 5. SEPARATION DISTANCE BETWEEN END OF INLET 3. AN INSPECTION PIPE OF AT LEAST 4 INCHES PIPE AND NEAREST POUR ON BAFFLE SHALL BE DIAMETER OR A MANHOLE SHALL BE LOCATED NO LESS THAN 6 INCURS OR NO MORE THAN 12 OVER BOTH THE INLET AND OUTLET DEVICES. INCHES. THE CENTER LINE OF THE INSPECTION PIPES 6. FOR HORIZONTAL CYLINDRICAL TANKS DIKENSION SHALL BE THE SAME AS THE CENTER LINE OF A IS 0.15D AND DIMENSION C IS 0.35D. THF RAFFIA: OA'F.NINCS OR SANITARY TEES. DETAIL 2 HORIZONTAL, CYLINDRICAL SEPTIC TANK I" MIN. LIQUID LEVEL L SLUDGE f -T -- A -. 4" DI MIN DIMENSIONS DIA 4 FT MINIMUM INSIDE DIAMETER A 0.15 D D 0.79 DIAMETER 8 6 IN MINIMUM 0.2 D MAXIMUM L 1 2 TO 3 TIMES THE DIAMETER C 0.35 D TO NEAREST INCH )LE A. DETAIL 3 COMPARTMENTED SEPTIC TANK SEPTIC TANKS LARGER THAN 3000 GALLONS SAND FABRICATED AS A SINGLE UNIT SHALL BE DIVIDi) INTO TWO OR MORE COMPARTMENTS. WHEN A SEPTIC TANK IS DIVIDED INTO TWO COMPARTMENTS, NOT LESS THAN ONE-HALF NOR MORE THAN TWO-THIRDS (* THE TOTAL VOLUME SHALL BE IN THE FIRST COMPARTMENT. WHEN A SEPTIC TANK IS DIVIDED INTO THREE OR MORE; COMPARTMENTS, ONE-HALF OF THE TOTAL VOLUME SHALL BE IN THE FIRST COMPAR171F.NT AND THE OTHER HALF EQUALLY DIVIDED IN THE OTHER COMPARTMENTS. CONNECTIONS BETWEEN COMPARTMENTS SHALL BE BAFFLED TO AS TO EFFECTIVELY RETAIN SCUM AND SLUDGE. ADEQUATE VENTING SHALL BE PROVIDED BETWEEN COMPARTMENTS BY BAFFLES OR BY AN OPENING OF AT LEAST SO SQUARE INCHES NEAR THE TOP OF THE COMPARTMENT WALL. ADEQUATE ACCESS TO EACH COMPARTMENT SHALL BE PROVIDED BY ONE OR MORE MANHOLES, AT LEAST 20 INCHES LEAST DIMENSION, AND LOCATED WITHIN SIX FEET OF ALL WALLS OF THE TANK. THE MANHOLE SHALL EXTEND THROUGH THE COVER TO A POINT WITHIN 12 INCHES BUT NO CLOSER THAN SIS{ INCHES BELOW FINISHED GRADE. THE MANHOLF. COVER SHAL1, BE COVF.RF:) WITH AT LEAST 6 INCHES OF FARTH . WHEN MULTIPLE TANKS ARE USED TO OBTAIN THE REQUIRED LIQUID VOLUME, THE TANKS SHALL BE CONNECTED IN SERIES. NO MORE THAN FOUR TANKS IN SERIES CAN BE USED TO OBTAIN THE REQUIRED 1.101,111) VOLUME. THE FIRST TANK SHALL BE NO SMALLER THAN ANY SUBSEQUENT TANKS IN THE SERIES. 4 SPECIAL SEPTIC TANK OUTLETS 2 In. Fj AIR VEN:-F T 12 in. LIQUID LEVEL — 12-18 In.) B. OUTSIDE u/�6 0 GAS BAFFLE I LIQUID LEVEL 2 in. C. SLUDGE DEFLECTOR - GAS BAFFLE OUTLET SCUM BAFFLE LIQUID LEVEL — A. GAS GAS DEFLECTION BAFFLE - -T 121n. TANK OUTLET PIPE Uri DETAIL 5 MANH PENCIL �I MARKS I I Zgel Q. II a II 7 �i MEASURE SCUM AND SLUDGE ACCUMULATIONS IN THE SEPTIC TANK DETAIL 6 II I INLET '"`�` SCUM"" i' I OUTLET •. '-;OUTLET LEVEL Y;: _� J v SCUM CLEAR SPACE � - - CLEAN OUT TANK WHEN: IS 3" OR LESS OR "B" IS 12' OR LESS kv BLACK COLOR lyiSLUDGE �_' DISTINGUISHES SLUDGE LAYlV FROM LIQUID �. MEASURE SCUM AND SLUDGE ACCUMULATIONS IN THE SEPTIC TANK DETAIL 6 HOUSE SUMP PUMP HOUSE 12" EARTH COVER SEPTIC TANK L HOUSE SEWER MIN. GRADE I IN 8 MAX. GRADE I" IN AT LEAST 10 FEET a ,. i � � SEWAGE Eel GRASS COVER 10- DROP BOXES OUTLET SEWER MIN. GRADE I" IN 8 FEET NO MAXIMUM GRADE FEET —`- 4 FEET 1 4" DISTRIBUTION PI PES DROP BOX - 4 WATER —TIGHT PIPES TREATMENT SYSTr-`l AT LEAST 4 1/2' OF UNDISTURBED `EARTH FOR CONSTRUCTION CONVENIENCE 1 WITH DfiOP BOXES DETAIL 7 1 I I I II I _4L EXTRA TRENCHES;) CAN BE (ADDED I F NECESSARY �� II WITH DfiOP BOXES DETAIL 7 4• _ Concrete Drop Box 3 -Watertight Pips From Septic Tank,., Supply Line To Next Drop Box Undisturbed Earth �- ' - I I' �r 1 ,,jai r;,' i.�� , , r Hay or Straw �� � 1 1 '[ [Jill I - � G ,� I� 1 i. i �-. j 1 1I'l ', 4 1� r ''fes 1 '(1 V�� .r.�i� 1 ' y�a�1 \ •\1'f �.I v', .� �1�1 40 Undisturbed Earth , All 4" Perforated Pipe Trench Rock }f LaDETAIL 8 INLET FROM SEPTIC TANK OR PREVIOUS DROP Box -7 `m-AINLE OUTLET TO TRENCH SUPPLY LINE TO NEXT DROP BOX OUTLET TO TRENCH NOTES I. ALL PIPES SHOULD BE AT LEAST 4 -INCH DIAMETER, 2. ELEVATION OF INLET AND SUPPLY LINE TO NEXT DROP BOX MAY BE ADJUSTED UP OR DOWN FOR DESIRED EFFLUENT LEVEL IN TRENCH. 3. SUGGESTED TRENCH LIQUID LEVEL IS AT TOP OF TRENCH ROCK IF PERMEABLE SYNTHETIC FABRIC COVERS ROCK; AT TOP OF OUTLET PIPE IF HAY OR STRAW COVERS ROCK. 4. INVERT OF INLET MUST BE AT LEAST ONE INCH HIGHER THAI4 INVERT OF SUPPLY PIPE TO NEXT DROP BOX. 5. TRENCHES MAr OUTLET ONE SIDE OR BOTH SIDES OF DROP BOX. - T SUPPLY I , INLET i I LINE ► " SUPPLY LINE 2" I -- ----- OUTLETS- _ _ TO TRENCH I ' OUTLET TO _ - - L---- TRENCH DROP BOX DETAIL 9 INLET 16" -1 12" SUGGESTED DIMENSIONS OF SQUARE DROP BOX CONSTRUCTED OF CONCRETE NOTE: ALL OPENINGS ARE CAST AS KNOCKOUTS AND ARE 6" DIAMETER OUTSIDE TAPERED TO 5" DIAMETER INSIDE OVER- FLOW OUTLET TO TRENCH -16 121,--- _, DETAIL 10 INLET SUGGESTED DIMENSIONS OF -' CIRCULAR DROP BOX CONSTRUC:T�-1 OF CONCRETE i NOTE: ALL OPENINGS ARE CAST AS KNOCKOUTS AND ARE I 6" DIAMETER OUTSIDE TAPERED TO 5" DIAMETER INSIDE 16" OVER- ft- FLOW VER-FLOW - - OUTLET TO TRENCH - DETAIL 11 DROP BOX DISTRIBUTION OF. EFFLUENT DETAIL 12 SERIAL DISTRIBUTION OF EFFLUENT DETAM 13 DROP BOX Do UT : vN SYSTEM DETAIL 14 SOUSE imp HOUSE 12" EARTH COVER SEPTIC HOUSE SEWER 4" TO 6" DIA. PA I N ''RADE I" IN 8 FEET MAX GRADE I" IN 4 FEET %T LEAST 10 FEET SEPTIC TANK Q DI80X STRIBUTION DISTRIBUTION 4 WATER -TIGHT PIPES GROUND SURFACE AT LPWEST TRENCH AT LEAST 12 HIGHER THAN OUTLETS OF DISTRI- BUTION 80X j �,7 i' i TRENCHES AT LEAST` 4'1/2' FEET OF � `UNDISTURBED CONSTRUCTIONEARTH FOR ` CONVENIENCE I I I I L_ -j I I V" DISTRIBUTIM PIPES SEWAGE TREATMENT SYSTEM WITH DISTRIBUTION BOX DETAIL 15 REMOVABLE BOTTOM OF INLET PIPE SHOULD HE A MIN I" HIGHER THAN BOTTOM OF OUTLET PIPE, 1 NLET DISTRIBUTION BOX COVER- - s jou L- BAFFLE EACH TILE FIELD LATERAL SHALL BE CONNECTED SEPARATELY AND NOT SUBDIVIDED. INVERTS SHALL BE AT THE SAME ELEVATION. OUTLET PIPES SHOULD HAVE EOUAL SLOPES FOR 5 FEET AFTER LEAVING BOX. 0 0., _OUTLET 900 OR 450 ELBOWS TO OBTAIN DESIRED LATERAL TILE LINE SEPARATION. BAFFLE TO BE USED WHEN EFFLUENT IS DELIVERED BY PUMP OR SIPHON, OR THE SLOPE OF THE INLET LINE IS SUCH THAT UNEVEN DISTRIBUTION COULD OCCUR. TOP OF THE BAFFLE AT LEAST LEVEL WITH THE CROWN OF THE INLET PIPE. DETAIL 16 TRENCH CONSTRUCTION DETAILS TRENCH ROCK COVERED WITH PERMEABLE" PIPE TO NEXT SYNTHETIC FABRIC OR 4" LAYER OF MARSH HAY OR INLET DROP BOX STRAW COVERED WITH UNTREATED BUILDING PAPER (RED ROSIN) EARTH BACKFILL ABOVE TOP OF ROCK �. DEPTH OF CLEAN ROCK 3/4" TO 2'/Z" DIA. 4" DIAMETER INSPECTION WELL WITH CAP SOP T/Or�/A� no* I -wr� 0 o y DROP BOX L 7/' 1 TRENCH LENGTH - - --- OVERFILL TO ALLOW NOTES: FOR SETTLING _ -�INSPECTION WELL BACKFILL 0 f(o OF SOIL ° BACKFILL o AL �. rZ 0 1 t O - Cr 2" DEPTH OF ___ROCK ABOVE C. 0 PIPE ROCK o OF s o ROCK BELOW PIPE I. BOTTOM OF TRENCH MUST BE LEVEL. TOP OF FRENCH ROCK MUST BE LEVEL. 2. DISTRIBUTION PIPE SHALL BE INSTALLED LEVEL'AND COVERED WITH 2 LACHES OF TRENCH ROCK. 3 DISTRIBUTION PIPE: SHALL BE PERFORATED PLASTIC WITH '/2 INCH OR LARGER HOLES. ONE OF THE ROWS OF HOLES MUST BE LOCATED ALONG THE BOTTOM OF THE PIPE. PIPE MUST HAVE A BEARING STRENGTH OF AT LEAST 1000 1-8/17T. 4. SCARIFY Tc?ENCH BOTTOM AND SIDEWALLS AS HIGH AS ROCK WILL BE PLACED IN THE TRENCH INORDER TO EXPOSE NATURAL SOIL. REMOVE LOOSE SOIL BEFORE PLACING ROCK. DETAIL 18 FINAL GROUND SURFACE J, J, L'A A-V : O O O O O C . �<<. c • t. MINIMUM ROCK C. �� DEPTH I � S 6" 6" OF SOIL COVER ct N O O O O O • C. .� .f�2" C•C4• OF ROCK c' C f�• � c�c c: ` C'c• C• BOTTOM OF TRENCH -� MINIMUM DISTANCE TO FINISH GRADE IS 4.5 FEET ( THIS COULD BE 3.0 FEET OF ORIGINAL SOIL AND 1.5 FEET OF FILL) MINIMUM DISTANCE IS 3.0 FEET OF SOIL SUITABLE FOR TREATMENT OF SEWAGE TANK EFFLUENT . SEASONALLY SATURATED SOIL OR IMPERVIOUS LAYER MINIMUM DEPTH AND SEPARATION REQUIREMENTS FOR DRAINF'IELD TRENCHES OR SEEPAGE BED DETAIL 17