© Presby Environmental, Inc., Maine Design & Installation Manual, June 2019 Edition -10-
14.8 Flow Equalizers Required
All distribution boxes used to divide effluent flow require flow equalizers in their outlets. Flow equalizers are limited to
a maximum of 20 GPM per equalizer.
14.9 Garbage Disposals (a.k.a. Garbage Grinders)
No additional AES or ES pipe is required when using a garbage disposal (grinder). If a garbage disposal is utilized,
follow the State’s requirements regarding septic tank sizing. Multiple compartment septic tanks or multiple tanks are
preferred and should be pumped as needed.
14.10 Pressure Distribution
The use of pressure distribution lines in
AES or ES Systems is
prohibited
. Pumps may be utilized when necessary
only to gain elevation and to feed a distribution box which then distributes effluent by gravity to the field.
14.11 Row Requirements
a) All beds must have at least 2 rows.
b) Maximum row length for any system is 100 ft.
c) Recommended minimum row length is 30 ft.
d) A combination (or D-box) distribution system must be
used if any row length is less than 30 ft. The D-box must
feed at least 30 ft. of pipe, a minimum of two D-box
outlets must be used and the field must be vented.
Illustration of row lengths less than 30 ft:
e) Row Center-to-Center Spacing is 1.5 ft. min. for all systems. Row spacing may be increased above
Table B and Table G requirements if desired.
f) For Sloping Beds: the elevations for each AES or ES row must be provided on the drawing.
g) All rows must be laid level to /- ½ in. (total of 1 in.) of the specified elevation and preferably
should be parallel to the contour of the site.
h) It is easier if row lengths are designed in exact 10 ft. increments since AES and ES pipe comes in 10 ft.
sections. However, if necessary, the pipe is easily cut to any
length to meet site constraints.
14.12 System Side Slopes (Side Slope Tapers)
Side slope tapering begins 3 ft. from the edge of the AES or ES pipe or 5 ft. on the downslope side of systems
sloping greater than 10% and is to be no steeper than 4:1 without a state waiver (see illustration in para. 39.0, pg.
29).
14.13 Separation Distances (Horizontal and Vertical)
Separation distances to the seasonal high-water table (SHWT) or other restrictive features are measured from the
outermost edge of the AES or ES pipe.
14.14 Sloping Sites and Sloping Mound Systems
a) The percentage of slope in all system drawings refers to the slope of the system, not the existing terrain
("site slope") and refers to the slope of the bed itself ("system slope").
b) The system slope and the site slope do not have to be the same (see para. 23.1, pg 16).
c)
Maximum site slope is 33% and maximum system slope is 20% (without a state waiver).
14.15 System Sand Bed Height Dimension
The height of an AES or ES Sand Bed measures 21 in. minimum (not including cover material):
a) 6 in. minimum of System Sand below the AES or ES pipe; and
b) 12 in. diameter of the pipe; and
c) 3 in. minimum of System Sand above the AES or ES pipe.
d) When a bed slopes over 10%, a minimum 3 ft. System Sand Extension area is required and is to be a
minimum of 6 in. deep (see illustration in para. 23.1, pg. 16).
SECT
ION #
1
SECT
ION #
2
SECT
ION #
3
LESS THAN 30'
INLET
SYSTEM SAND EXTENSION
FOR SLOPES OVER 10%
V
E
N
T
MA
NIFO
LD
VENT
D-BOX
