HomeMy WebLinkAbout1989-11-09 Septic System Redesign»
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ADVANCE SURVEYING & ENGINEERING CO.
5811 CEDAR LAKE ROAD MINNEAPOLIS. MINNESOTA 55416 PHONE: 541 0500
November 9, 1989
Mr. Jerry Boldenow
16912 Excelsior Boulevard
Minnetonka, MN 55345
Phone: 934 0106
OCT-91989
Dear Jerry:
After a meeting on site last week, between your client, Mike
Gafron of the City of Orono, and th3 other site evaluator, it was
decided that your client's interes.o might be best served by a
revised design. I have attached new calculations and quantities.
It was decided that the western system would remain a drop box
system with effluent being pumped to the highest drop box and
then flowing through the system by gravity. This system will be
used as an alternate or backup system. The trenches in this
system will be kept as shallow as possible and will vary in
elevation as they step downhill toward the marsh. We have also
lengthened the trenches in this system and eliminated one trench
to give more room for the swimming pool.
The eastern system is now designed as a pressurized distribution
system. The bottom of the trenches in this system must be level
with each other but the depth of the trenches will vary to allow
drainage of the ground surface. We have also eliminated one
trench in this system and lengthened the trenches a bit to give
more room for the swimming pool. You should note that the pump
for the pressure system will be larger than the pump for the
gravity system.
If you or the installer have questions, please call
Sincerely,
C
ADVANCE SURVEY BERING CO.G & EN
James H. Parker P.E. & L.S.
Minn. Lie. No. 9235, PCA 208
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CALCULATIONS FOR SYSTEM DESIGN
Septic tank liquid capacity
Length of trenches
Lateral length
Perforation spacing
Perforations per lateral
Number of laterals
Total number perforations
Perforation diameter
Required flow
Lateral diameter
Elev. diff. pump to manifold
Pressure reqd. ® manifold
Friction loss
Total head required
Drainback quantity
Width of system
Length of system
Area required for system
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1500 gallons
30.1 feet
28.5 feet
3 feet
10
10
100
0.25 inch
74 gpm
2 inch
14 feet
5 feet
23 feet
42 feet
33 gallons
33 feet
60 feet
1984 sq.ft.
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PRESSURIZED TRENCH SYSTEM (PRIMARY)
Number of bedrooms ?
Sewage flow ?
Basis of estimate ?
SOILS
6
900 gallons per day
Type I residence. 6 bedrooms @150 gpd each s 900 gallons per day.
Depth to restriction ?
Desc. of restriction
Perc. rate 2
Perc. rate 3
Average perc. rate
8 feet
Soil mottling at this depth and below, indicates saturated soils
7 mpl
31 mpl
19 mpl
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SYSTEM
Elev. of low floor ?
Elev. of treatment area
Trench width ?
Trench spacing ?
Depth of rock below pipe ?
How many laterals ?
Dist. home to septic tank #1 ?
944.5
951.5
3 feet
7.5 feet
24 inches
10
80 feet
Dist. pump tank to far lateral 190 feet
Pump line diameter ?
Soil OK for backfill?
2 inches
Yes
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STANDARD TRENCH SYSTEM DESIGN
(ALTERNATE) PUMPING TO DROP BOX SYSTEM
FLOW
How many bedrooms ?
Sewage flow ?
Basis of estimate ?
SOILS
6
600 gallons per day
Type I l esidence, 6 bedrooms @ 150 gpd each » 900 gallons per day.
Depth to restriction ?
Desc. of restriction
Perc. rate ^
Perc
Avei ate
8 feet
Bottom of soil boring
12 mpi
7 mpi
9.5 mpi
SYSTEM
Trench width ?
Trench spacing ?
Depth of rock below pipe ?
How many drop boxes ?
DIst. home to septic tank ?
Dist. septic tank to system ? 260 feet
Soil OK for backfill? Yes
3 feet
7.5 feet
24 inches
5
10 teet
CALCULATIONS FOR SYSTEM DESIGN
Septic tank liquid capacity 1500 gallons
Length of 4' perforated dis
tribution laterals 23 feet
Width of system 33 feet
Length of system 46 feet
Lawn area required for syst 1509 sq.ft.
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