SEPTIC SYSTEM DESIGN

Ken Stratton

SUBSURFACE WASTEWATER TEAM

DAVID BRALEY (SUPERVISOR)

(1ST TIME VARIANCES-HIP REVIEWS) JIM JACOBSEN (1ST TIME VARIANCES-HIP REVIEWS)

GLENN ANGELL (SITE EVALUATORS)

(LPI’S & REPLACEMENT VARIANCES) BRENT LAWSON (LPI’S & REPLACEMENT VARIANCES)

THESE RULES ARE IN PLACE FOR HEALTH AND SAFETY

TYPES OF SYSTEMS STONE DISPOSAL FIELD

INFILTRATOR - BIO-DIFFUSER

ENVIROSEPTIC TUBES - GEOFLOW

ELJEN GSF (IN-DRAINS)

CONCRETE CHAMBERS

90 GALLONS PER DAY / PER BEDROOM 594 square feet of disposal field BASE DESIGN FLOW 2 BEDROOM HOUSE 90 GALLONS PER DAY / PER BEDROOM 2 x 90 180 gallons per day Soil profile is 3 = 3.3 sq. ft. per gallon 180 x 3.3 594 square feet of disposal field

594 square feet of disposal field STONE TRENCH 20’ 2’ WIDE = 4 SQ. FT./ LINEAR FT. = 600 sq. ft. 594 / 4 = 148.5 FEET OF TRENCH 3’ WIDE = 5 SQ. FT. / LINEAR FT. 594 / 5’= 118.8 FEET OF TRENCH 2’ 3’ 30’ 119’ 149’ STONE DISPOSAL FIELD

PROPRIETARY DEVICES STONE FIELD = 20’ X 30’ INFILTRATOR CLUSTER = 36 SQ. FT. /UNIT TRENCH = 44 SQ. FT. / UNIT CLUSTER TRENCH 594 / 36 = 16.5 (17) units 594 / 44 = 13.5 (14) 3 ROWS OF 6 UNITS 1 56’ ROW 2 28’ROWS APPROX. 24’ X 11’ STONE FIELD = 20’ X 30’

TRENCH CONFIGURATION ONLY PIPE SPACING MIN. 1.5 FEET CENTER TO CENTER PROPRIETARY DEVICES PRESBY TUBING TRENCH CONFIGURATION ONLY PIPE SPACING MIN. 1.5 FEET CENTER TO CENTER 5 SQ. FT. / LINEAR FOOT 40’ 60’ 594 / 5 = 118.8 (119) LINEAR FEET 210 SQ. FT 2.5 FT SPACING 180 SQ. FT 4 FT SPACING STONE FIELD = 20’ X 30’

PROPRIETARY DEVICES STONE FIELD = 20’ X 30’ Eljen in-drains / GSF units TYPE A 594 / 24SQ. FT = 24.75 (25 UNITS) TYPE B 594 / 48 SQ. FT = 12.3 (13 UNITS) STONE FIELD = 20’ X 30’

PROPRIETARY DEVICES Concrete Chambers STONE FIELD = 20’ X 30’ CLUSTER 4’ x 8’ = 64 SQ. FT / UNIT—9.2 (10 UNITS) 8’ X 8’ = 128 SQ. FT. / UNIT----4.6 (5 UNITS) TRENCH 4’ X 8’ WITH 1’ OF STONE ALONG THE 4’ LENGTH = 77 SQ. FT./UNIT---7.7 (8UNITS) 8’ X 8’ WITH 1’ OF STONE ALONG THE 8’ LENGTH = 90 SQ. FT /UNIT—6.6 (7 UNITS) STONE FIELD = 20’ X 30’

DISPOSAL FIELDS MUST BE LEVEL SATURATE ONE END OF THE DISPOSAL FIELD DEFINITION OF LEVEL NOT TO EXCEED 2” IN 100 FEET STONE SCARIFICATION / TRANSITIONAL HORIZON SATURATE ONE END OF THE DISPOSAL FIELD MALFUNCTION

SYSTEMS AND SLOPES STONE FIELD

SYSTEMS AND SLOPES STONE FIELD

SYSTEMS AND SLOPES STONE FIELD

SYSTEMS AND SLOPES STEP DOWN TOP VIEW

SYSTEMS AND SLOPES STEP DOWN GSF UNITS TOP VIEW

MULTI – PORT DISTRIBUTION BOX

IF ITS NOT LEVEL, IT WONT WORK HOW DOES THE DISTRIBUTION BOX FEED EVENLY TO EACH ROW IF ITS NOT LEVEL, IT WONT WORK

SYSTEMS AND SLOPES STEP DOWN GSF UNITS PIPING IN SERIES PARALLEL TOP VIEW

What if the downslope fill extension cant catch up with itself?

If shorter distance is required, becomes a state variance A man-made retaining wall, provided the retaining wall is no more than 24 inches in height and the horizontal distance from the outer edge of the fill shoulder to the retaining wall is at least 10 feet. If shorter distance is required, becomes a state variance 10’ 3’ 10’ prevent any under drain of the disposal field This provision applies only to soils with AIII, B, or C limiting factor conditions, located beneath and downslope of the disposal field

IF WORKING IN THE SZ, MUST BE CERTIFIED IN EROSION CONTROL SHORELAND ZONE 100’ 75’ 250’ SHORELAND ZONE IF WORKING IN THE SZ, MUST BE CERTIFIED IN EROSION CONTROL THROUGH DEP

H20 LOAD RATING SYSTEMS AND SLOPES STEP DOWN Vehicular traffic: Except where site limitations make it impractical, no driveway or parking or turning area may be located over any disposal field. When a system is placed under an area receiving vehicular traffic, H-20 loading components must be installed.

Original ground FILTER FABRIC Scarification Min. 4” Backfill Transitional Horizon and mix Min. 4” Cover Stone & Pipe

H20 LOAD RATING SYSTEMS AND SLOPES Vehicular traffic: Except where site limitations make it impratical, no driveway or parking or turning area may be located over any disposal field. When a system is placed under an area receiving vehicular traffic, H-20 loading components must be installed. GSF systems shall not be installed under paved or concreted areas. Infiltrator Chamber H-20 load rating with 18” of cover. 12” fill under pavement and on top of 6” of system sand above tubes Fabric is added on top of the System Sand. All H-20 systems require venting.

H20 LOAD RATING INFILTRATORS 18” COVER BACKFILL PER SPECS SCARIFICATION & TRANSITION HORIZON

H20 LOAD RATING 12” OF BACKFILL FILTER FABRIC 6” AROUND TUBES OF SYSTEM SAND SCARIFICATION & TRANSITIONAL HORIZON

CONCRETE CHAMBERS

2 things that come up that effects the disposal systems that is actually a fixture on the internal plumbing

the use of septic tank outlet filters Garbage disposal: Garbage disposals should not be used with disposal fields. However, if such units are proposed to be used, other measures must be taken, such as: increasing septic tank capacity by a minimum of 30 percent the installation of a second septic tank installed in series; or a multiple compartment septic tank the use of septic tank outlet filters must be included in the system design to prevent suspended solids from entering the disposal field

Water Filtration Devices If known, amount of gallons backwashed should be added into the design

3 bed field 2 SEPERATE DWELLINGS 1 – 3 BEDROOM = 270 GPD 1000 1 - 1 BEDROOM (MIN DESIGN 2 BEDROOMS) 2 BEDROOMS = 180 GPD 3 bdrm 5 BEDROOMS + 1 bedroom garage

3 bed field 2 SEPERATE DWELLINGS 5 BEDROOMS 1000 TANK SIZE= 3 bdrm + 1 bedroom garage

1 dwelling = 3 bedrooms 1 dwelling = 2 bedrooms 5 bedrooms total

1 dwelling = 3 bedrooms 1 dwelling = 2 bedrooms 5 bedrooms total 1750 gal. 1 dwelling = 3 bedrooms 1 dwelling = 2 bedrooms 5 bedrooms total

3 bed field Expand by 2 bed 2 SEPERATE DWELLINGS 5 BEDROOMS 1000 TANK SIZE= 1750 gal. 3 bdrm 750 + 1 bedroom garage

3 bed field Expand by 2 bed 2 SEPERATE DWELLINGS 5 BEDROOMS 1000 TANK SIZE= 1750 gal. 3 bdrm 750 + 1 bedroom garage

3 bed field 1 UNIT = 4 BEDROOMS 2 SEPERATE DWELLINGS 5 BEDROOMS 1000 TANK SIZE= 1000 gal. 1750 gal. Shoreland zone = install expansion 3 bdrm Outside = record with Reg. of Deeds + 1 bedroom garage

MERRY CHRISTMAS