© Presby Environmental, Inc., Maine Design & Installation Manual, June 2019 Edition -27-
38.22 GPD and GPM
An acronym for Gallons Per Day and Gallons Per Minute respectively.
38.23 High and Low Vents
Pipes used in differential venting. Detailed information about venting requirements can be found in Venting
Requirements, para. 32.0, pg. 19.
38.24 High Strength Effluent
High strength wastewater is septic tank effluent quality with combined 30-day average carbonaceous biochemical
oxygen demand (CBOD) and total suspended solids (TSS) in excess of two-hundred and forty (240) mg/L.
38.25 MPI
An acronym for Minutes Per Inch and is the numerical value by which percolation rates (also called “perc rates”) are
expressed.
38.26 Multi-Level™
A Multi-Level™ System is a patented process using AES or ES pipe; it consists of essentially two systems installed in
the same bed with one system on top of another with 6 in. of System Sand between the two levels. Multi-Level
Systems are approved for use in Soil Profiles 2, 4, 5 & 6 (see illustrations in para. 16.0, pg. 12).
38.27 Multiple Bed Distribution
Incorporates two or more beds, each bed with Basic Serial, Combination Serial, or D-box distribution and receiving
effluent from a distribution box (see para. 22.0, pg. 15).
38.28 Non-Conventional Configurations
Have irregular shapes or row lengths shorter than 30 ft. to accommodate site constraints (see para. 15.1, pg. 11).
38.29 Offset Adapter
A plastic fitting with a 4 in. hole installed at the 12 o’clock position which allows for connections from one row to
another and for installation of venting (see para. 3.2, pg. 4).
38.30 Percolation Rate
Also known as Perc Rate, is a numerical indication of a soil’s hydraulic capacity, expressed in minutes per inch (MPI.)
38.31 Pressure Distribution
A pressurized, small-diameter pipe system used to deliver effluent to an absorption field. Pressure Distribution is not
permitted to be used with the AES or ES system
as these
systems are designed to promote even distribution without
the need for pressure distribution.
38.32 Pump Systems
Utilize a pump to gain elevation in order to deliver effluent to a D-box (see para. 30.0, pg. 17).
38.33 Raised Connection
A U-shaped, 4” diameter, PVC pipe configuration which is used to connect rows oriented in a serial configuration and
to maintain the proper liquid level inside each row. See drawing in para. 3.5, pg. 4.
38.34 Raking and Tilling
Refers to methods of preparing the native soil that will be covered with System Sand or Sand Fill, creating a
transitional layer between the sand and the soil. See Installation Requirements para. 34.7, pg. 22.
38.35 Row
Consists of a number of pipe sections connected by couplings with an Offset Adapter on the inlet end and an
Offset Adapter or End Cap on the opposite end. Rows are typically between 30 ft. and 100 ft. long (see Row
Requirements in para. 14.11, pg. 10).
38.36 Sand Fill
Clean sand, free of organic materials and meeting the specifications set forth in Sand Fill, para. 31.4, pg. 18. Sand fill
is used to raise the elevation of the system to meet required separation distance or for use in side slope tapers.
System Sand may be used in place of Sand Fill.