Eljen Mantis M5 Series User manual

System Design & Installation Manual
www.eljen.com
CORPORATION
Innovative Environmental Products & Solutions Since 1970
TM

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Table of Contents
Topic
Page
Numbers
Glossary of Terms
3
Mantis M5Series General Description
4
1.0 General System Information
6
2.0 Systems for Level Sites
7
3.0 Systems for Sloped Sites
7
4.0 Trench Installation and Design Guidance
8
5.0 Pumped System Guidance
11
6.0 System Ventilation Guidance
12
7.0 System Care and Maintenance
14
8.0 Recommended Notes on Design Plans
15
Tables
Table 1 Specified Sand Sieve Requirements
3
Table 2 Mantis M5 Trench Sizing Table
5
Mantis M5Drawings
Fig. 1 Mantis M5Components
4
Fig. 2 Mantis M5Trench Cross Section
7
Fig. 3 Mantis M5Multiple Trench Cross Section
10
Fig. 4 Mantis M5Multiple Trench Plan View
10
Fig. 5 Mantis M5Series Pressure Distribution –Orifice Layout
11
Fig. 6 Mantis Series Venting Diagram
12
Fig. 7 Mantis Series 2” By-Pass Line, Close Up
13

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Glossary of Terms
Mantis M5Series Units The Mantis M5Series units come preassembled and are 5 feet in length (as measured
from the Support Distribution Pipe) and 12” high. 12” and 24” wide models are
available. The 12” wide model is the Mantis 5.1, and the 24” wide model is the Mantis
5.2. All models have 6” of specified sand under and to the sides of the product. 1” of
specified sand is placed over the units prior to backfill.
Support Distribution Pipe The Mantis M5Series Support Distribution Pipe is 5 feet in length and constructed from
crush resistant PVC Pipe. The pipes provide 3 pre-drilled one inch holes within each
Filter Support Module at the 12, 5 and 7 o’clock position.
Filter Support Module There are 5 Filter Support Modules for each M5unit. All Filter Support Modules are 4”
thick. The 5.1 model is 12” wide and the 5.2 model is 24” wide.
Specified Sand The Specified Sand envelope around the Mantis M5Series (6” minimum underneath, 6”
minimum on the sides, 1” minimum on the top, and 8” in-between the Support Modules)
shall meet the requirements as indicated in the Specified Sand Requirements chart
listed below. This sand is an ASTM C33 WASHED CONCRETE SAND WITH LESS
THAN 10% PASSING #100 SIEVE AND LESS THAN 5% PASSING A #200 SIEVE.
Ask your material supplier for a sieve analysis to verify that your material meets the
required specifications.
Table 1: SPECIFIED SAND SIEVE REQUIREMENTS
Eljen Mantis M5Series
ASTM C33 Specified Sand Requirements
Sieve Size
Sieve Square
Opening Size
Specification
Percent Passing
(Wet Sieve)
0.375”
9.5 mm
100.0
#4
4.75 mm
95.0 –100.0
#8
2.36 mm
80.0 –100.0
#16
1.18 mm
50.0 –85.0
#30
600 µm
25.0 –60.0
#50
300 µm
5.0 –30.0
#100
150 µm
< 10.0
#200
75 µm
< 5.0
Request a sieve analysis from your material supplier to ensure that
the system sand meets the specification requirements listed above.
Design Flow The estimated peak flow that is used to size a GSF system is 150 gallons per day per
Bedroom for an 8 bedroom or less dwelling.

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Mantis M5General Description
Note: Design layouts and installation instructions for sequential, equal or dosed distribution systems are included. Details on unique design and
construction procedures are also provided. To receive design standards for specially engineered dosing systems or commercial systems, contact Eljen’s
Technical Resource Department at 1-800-444-1359. Mantis M5 series systems must be designed and constructed according to this Design & Installation
Manual and the Alabama regulations governing the design, installation and operation of on-site wastewater treatment and disposal systems (hereinafter
the Regulations).
________________________________________________________________________________________________________________________
How the Mantis M5Series System Works
The Eljen Mantis M5Series is a wastewater dispersal and disposal technology that applies clarified effluent to the native
soil through a proprietary filtering process. The Mantis M5protects the native soils long term acceptance rate by keeping
the biological growth off the native soils and within the Mantis M5units. The Mantis M5 utilizes 3-D Mini-Trenches™ to
improve effluent quality resulting in greater performance, reliability, and ease of operation.
•The perforated Support Distribution Pipe is centered within the Mantis M5 and provides internal distribution of
septic tank effluent while securing the five Filter Support Modules.
•The Filter Support Modules filter septic tank effluent and act as individual 3-D Mini-Trenches™ within the systems
footprint. Each module consists of a cuspated core surrounded by Bio-Matt™ geotextile fabric. The Mantis M5’s
unique design increases the available surface area within each module. This is known as Infiltrative Surface
Optimization (ISO) and provides a system surface area that greatly exceeds that of the Filter Support Module, a
traditional gravel trench or that of gravel replacement technology.
•Open air channels within the Filter Support Modules support and promote fixed aerobic bacterial growth on the
Bio-Matt™ geotextile fabric interface.
•Septic tank effluent migrates through the Filter Support Modules and into the Specified Sand layer which
surrounds each Mantis M5 unit. The Filter Support Module clarifies septic tank effluent and assists in its delivery to
the Specified Sand. This process promotes unsaturated flow in the Specified Sand and native soils while
maintaining the native soils structure, long term acceptance rate, and its ability to effectively absorb the clarified
effluent.
•The Specified Sand layer also protects the native soil from compaction, helps maintain existing pore spaces
within the native soil column, and preserves the native soil’s natural infiltration capacity which is critical for long-
term performance.
FIGURE 1: MANTIS M5COMPONENTS

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Mantis M5Series Sizing
TABLE 2: Mantis M5Trench Sizing Table
1. The disposal area shown above reflects a 40% reduction to conventional systems
2. Mantis M55.1 unit = 2.0 ft²/lf or 10.0 ft² per unit
3. Mantis M55.2 unit = 3.0 ft²/lf or 15.0 ft² per unit
Soil Texture Group Perc Rate
Square feet per
Bedroom
Square feet per
Bedroom
M5.1 Units per
Bedroom
Square feet per
Bedroom
M5.1 Units per
Bedroom
Group 1 5 - 15 200 120 12 120 8
Group 2 16 - 30 250 150 15 150 10
Group 3 31 - 60 300 180 18 180 12
61 330 198 20 198 14
65 350 210 21 210 14
70 370 222 23 222 15
75 390 234 24 234 16
80 410 246 25 246 17
85 430 258 26 258 18
90 450 270 27 270 18
95 480 288 29 288 20
100 510 306 31 306 21
105 540 324 33 324 22
110 570 342 35 342 23
115 600 360 36 360 24
120 650 390 39 390 26
121 680 408 41 408 28
130 710 426 43 426 29
135 740 444 45 444 30
140 770 462 47 462 31
145 800 480 48 480 32
150 830 498 50 498 34
155 860 516 52 516 35
160 890 534 54 534 36
165 920 552 56 552 37
170 950 570 57 570 38
175 980 588 59 588 40
180 1010 606 61 606 41
185 1040 624 63 624 42
190 1070 642 65 642 43
195 1100 660 66 660 44
200 1130 678 68 678 46
205 1160 696 70 696 47
210 1190 714 72 714 48
215 1220 732 74 732 49
220 1250 750 75 750 50
225 1280 768 77 768 52
230 1310 786 79 786 53
235 1340 804 81 804 54
240 1370 822 83 822 55
Group 4
Group 5 b
Alabama Conventional Field Sizing
M5.1
M5.2

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1.0 General System Information
1.1 TREATMENT FIELD SIZE AND NUMBER OF UNITS: System size will vary depending on design flow and soil
analysis. Table 2 indicates the minimum number of Mantis units required for various soil percolation rates and design
flows.
1.2 NON-RESIDENTIAL BUILDINGS & RESIDENTIAL INSTITUTIONS: Commercial systems require different sizing
and design criteria as compared to residential systems. Please contact Eljen’s Technical Resource Department at 1-800-
444-1359 for more information on commercial systems.
1.3 DEPTH TO GROUND WATER OR RESTRICTIVE LAYER: As required by state regulations; the limiting zone shall
be measured from the bottom of the unit to the restrictive layer. Separation distances are listed in Table 15 of Appendix A
in the guidelines.
1.4 SPECIFIED SAND SPECIFICATION FOR TRENCH SYSTEMS: The first 6 inches of Specified Sand immediately
under, between Filter Support Modules, between unit rows and around the perimeter of the Mantis M5Series system must
be an ASTM C33 WASHED CONCRETE SAND WITH LESS THAN 10% PASSING A #100 SIEVE AND LESS THAN
5% PASSING A #200 SIEVE.
1.5 VEHICULAR TRAFFIC AND PAVED AREAS OVER SYSTEM: All vehicular traffic is prohibited over the Mantis
system. This is due to the compaction of material required to support traffic loading. Compaction greatly diminishes
absorption below the system and reduces the void space that naturally exists in soils for oxygen transfer and water
migration. For shallow installations, light-weight track-mounted machines are best for setting the final grade. It is also
permissible to back-blade the soil to set final minimum cover.
1.6 SYSTEM VENTING: Eljen mandates venting when the system has greater than 18” of cover material as measured
from the top of the unit to finished grade. This will ensure proper aeration of the units.
1.7 BACKFILL & FINISH GRADING: Complete backfill over the Mantis M5units followed by topsoil to a depth of 12” as
measured from the top of the units. 1” of the fill is Specified Sand, immediately on top of the unit. Systems with total
cover that exceeds 18” as measured from the top of the units to finished grade shall be vented at the distal (far) end of the
system. Backfill material shall be well graded sandy fill; clean, porous, and devoid of large rocks. Divert surface runoff
with diversion ditches or berms. Finish grade to prevent surface ponding. Seed or sod excavated areas to protect against
erosion.
1.8 EFFLUENT FILTERS: Effluent filters are recommended as a means of preventing solids from leaving the tank.
1.9 DISTRIBUTION PIPE LAYOUT: No additional distribution pipe is needed to connect units to one another. The
support distribution pipe runs along the center of the units and provides distribution for all configurations.
1.10 GARBAGE DISPOSALS: The use of a garbage disposal is not recommended as they can cause septic system
problems by generating an increased amount of suspended solids, grease and nutrients. Design drawings shall include a
note “Garbage disposals shall not be used with this system”.
However, if such units are proposed to be used, other measures should be taken to mitigate the increased nutrients to the
field. Increasing the number of units used in the system or increasing the design flow would help. Please contact Eljen
Corporation’s Technical Department with any questions, 1-800-444-1359.
NOTE: Eljen recommends the use of septic tank outlet effluent filters on all systems, especially on those systems that a
garbage disposal is installed, even if the tanks design capacity has been increased. Filters with higher filtration are
recommended for systems with garbage disposals.
1.11 ADDITIONAL FACTORS EFFECTING RESIDENTIAL SYSTEM SIZE: Homes with expected higher than normal
water usage should consider increasing the septic tank volume as well as increasing the size and number of units in the
disposal area. For example: Homes with tubs holding more than 100 gallons or utilizing other high use fixtures and
homes with higher than normal occupancy should consider septic tank and drain field modifications.

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1.0 General System Information
1.12 WATER SOFTENERS OR CONDITIONERS: Discharge of water softener or conditioner backwash to Eljen
Products is not allowed. Discharge from these devices shall be into a separate disposal system meeting the requirements
of State and Local Regulations.
1.13 PLANS AND SPECIFICATIONS: Typical treatment system drawings and specifications are shown at the end of this
manual. When used in conjunction with a permit sketch, site specific specifications, and manufacturer installation criteria,
these documents will normally be sufficient to assure a system can be properly installed. In some instances where a
complex system is encountered, formal plans and specifications may be required. This determination is left to the
discretion of the District Health Department.
FIGURE 2: MANTIS M5TRENCH CROSS SECTION
2.0 Design for Level Sites
TRENCH ROW SPACING: A minimum distance of six (6) feet shall separate laterals in a trench disposal system. The
Mantis M5units and Specified Sand must be installed level at their design elevations.
3.0 Design for Sloped Sites
TRENCH ROW SPACING: A minimum distance of six (6) feet shall separate laterals in a trench disposal system. The
Mantis M5units and Specified Sand must be installed level at their design elevations.
24"
SPECIFIED SAND
TOPSOIL
CLEAN BACKFILL
VEGETATIVE COVER
ø 4" WITH
HOLESAT 12,
5 & 7 O'CLOCK
6" MIN
12"
6"
1"
12"
6"
MANTIS5.1
12" MIN
36"
SPECIFIED SAND
TOPSOIL
CLEANBACKFILL
VEGETATIVE COVER
ø 4" WITH
HOLESAT 12,
5 & 7 O'CLOCK
6" MIN
24"
6"
1"
12"
6"
MANTIS5.2
12" MIN

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4.0 Trench Installation and Design Guidance
Trench Design Example
House size –4 Bedrooms
Percolation Rate min/in –60 min/in
Design Flow –150 gpd x 4 bedrooms = 600 gpd
Refer to Table 2
Lookup the Percolation Rate in Table 2 and determine the square foot area per bedroom and number of units needed per
bedroom:
Multiply values by number of bedrooms to determine minimums:
Disposal Area: 180 ft2x 4 Bedrooms = 720 ft2
M5.1 Units: 18 Units x 4 Bedrooms = 72 Units
M5.2 Units: 12 Units x 4 Bedrooms = 48 Units
(Note: Units required may result in a larger footprint than the disposal area required. Default to units required.)
Calculate Minimum Trench Length
Multiply numbers of units required by 5 feet.
M5.1: 72 units x 5 ft/unit 360 linear ft
M5.2: 48 units x 5 ft/unit 240 linear ft
Minimum Trench Width
M5.1: 1 ft width for the product with 6 inches of sand on each side = 2 ft
M5.2: 2 ft width for the product with 6 inches of sand on each side = 3 ft
Final Dimension Layout
(Note: System layout and number of rows will vary based on site constraints)
M5.1
Total Trench Length 360 ft
Trench Width 2 ft
Minimum Number of Units 72 M5.1 Units
System Area 720 ft2
M5.2
Total Trench Length 240 ft
Trench Width 3 ft
Minimum Number of Units 48 M5.2 Units
System Area 720 ft2
Soil Texture Group Perc Rate
Square feet per
Bedroom
Square feet per
Bedroom
M5.1 Units per
Bedroom
Square feet per
Bedroom
M5.1 Units per
Bedroom
Group 3 31 - 60 300 180 18 180 12
Alabama Conventional Field Sizing
M5.1
M5.2

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4.0 Trench Installation and Design Guidance
1. Carefully lay out all boundaries defining the location and elevation for all system components.
2. Prepare the site according to state and local regulations. Do not install a system on frozen or saturated soils. Take
precautions not to compact or smear the area with heavy machinery.
3. Plan all drainage requirements above (up-slope) the system and set soil grades to insure storm water drainage and
surface water is diverted away from the disposal area once the system is complete.
4. Excavate a minimum thirty-six inch (36”) wide level trench for the Mantis 5.2 unit or a minimum twenty-four inch (24”)
wide level trench for the Mantis 5.1 unit. Remove all organic soil, roots, and rocks within the disposal trench area.
5. Scarify receiving layers including sidewalls to eliminate soil smearing. Once scarifying is completed, avoid walking
over prepared disposal area until the Specified Sand has been placed on the bottom of the trench.
6. Place, compact, and rake a minimum 6” level layer of Specified Sand along the trench bottom. Specified Sand must
meet the minimum requirements listed on Table 1 of this manual. Ask your material supplier for a sieve analysis
report to verify that the sand you are going to install meets this specification. A hand tamper or a vibratory plate
compactor is sufficient for compaction of the Specified Sand layer.
7. Center the Mantis units in the trench with the fabric side up, adjust the Filter Support Modules to ensure they are
spaced evenly and have not shifted during placement.
8. Connect the units by inserting the Support Distribution Pipe to one another. Direction changes are accomplished by
using a variety off the shelf fittings.
9. Install a termination cap or vent piping if required at the distal (far) end of the distribution pipe.
10. Begin placing Specified Sand between the Filter Support Modules and to the sides of the units.Specified Sand must
be placed lightly and may be accomplished with a backhoe or other suitable equipment. DO NOT dump full loads of
Specified Sand directly on the units.
11. Steps for placement of Specified Sand.
a. Starting at the top center of the units, use a minimal amount of Specified Sand necessary to set in place
the bottom section of the Filter Support Modules at their correct spacing.
b. Compact the sand that is in-between the Filter Support Modules. Ensure that the void area under the
Support Distribution Pipe is filled and compacted with Specified Sand.
c. Additional Specified Sand is lightly added between the Filter Support Modules and along the sides of the
Mantis units to bring the sand fill 1-inch above the Filter Support Modules to account for sand settling.
d. Continue to moderately tamp and compact the sand that is in-between the Filter Support Modules.
Spread additional Specified Sand as necessary.
12. Set distribution box to the proper elevation to achieve a 1/8”drop per foot to the first unit. Make the connection to the
beginning of the first unit from the distribution box with SDR-35 pipe or equivalent.
13. Complete backfill over the Mantis M5units followed by topsoil to a depth of 12” as measured from the top of the units.
1” of the fill is Specified Sand, immediately on top of the unit. Systems with total cover that exceeds 18” as measured
from the top of the units to finished grade shall be vented at the distal (far) end of the system. Backfill material shall
be well graded sandy fill; clean, porous, and devoid of large rocks. Divert surface runoff with diversion ditches or
berms. Finish grade to prevent surface ponding. Seed or sod excavated areas to protect against erosion. Do not
drive or pave over the disposal area.

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4.0 Trench Installation and Design Guidance
FIGURE 3: MANTIS M5MULTIPLE TRENCH CROSS SECTION
SPECIFIED SAND
NATIVE
SOIL
6"
24"
SPECIFIED SAND
12"
12"
6"
SPECIFIED SAND
12" MIN COVER
INCLUDES 1" OF SPECIFIEDSAND
NATIVE
SOIL
6" 24"
SPECIFIED SAND
18"
12"
6"
12" MIN COVER
INCLUDES 1" OF SPECIFIEDSAND
MANTIS5.1
MANTIS5.2
6' MIN
6' MIN
FIGURE 4: MANTIS M5MULTIPLE TRENCH PLAN VIEW
NATIVE SOIL
SEPTIC
TANK
PER DESIGN
6"
PER DESIGN
DISTRIBUTIONBOX
SPECIFIED SAND

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5.0 Pumped System Guidance
5.1 PUMP DOSED DISTRIBUTION BOX: Specify an oversized distribution box for pumped systems. Provide velocity
reduction in the D-box with a tee or baffle.
5.2 PRESSURE OR PUMPED DOSED DESIGN CRITERIA: Dosing volume must be set to deliver a maximum of 6
gallons per Mantis 5.2 per dose cycle or 3 gallons per Mantis 5.1 per dose cycle.
5.3 LOW PRESSURE DISTRIBUTION: Adhere to the regulations. Design requirements will vary depending on length of
system and dose volume. At least one drain hole per line at the 6 o’clock position must added to each line.
Flushing ports are required at the distal end of all pressure distribution networks. Flushing valves and vents can be
consolidated in larger systems by using valves on the outlet manifold.
FIGURE 5: MANTIS M5SERIES PRESSURE DISTRIBUTION –ORIFICE LAYOUT
FROM
PUMPCHAMBER
LOWPRESSURE PIPE
(LPP)
CAP END OF 4" PIPE
4" DIAMETER
PERFORATEDPIPE

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6.0 System Ventilation Guidance
SYSTEM VENTILATION: Air vents are required at the distal end of unit rows on all disposal systems with more than 18
inches of soil cover as measured from the top of the Mantis units or located under impervious surfaces. This will ensure
proper aeration of the Mantis system. The extension of the distribution pipe at the distal end of each row to the vent
provides adequate delivery of air into the Mantis system, as shown in Figure 10.
The vent is usually a 4-inch diameter pipe extended to a convenient location behind shrubs. Corrugated pipe can be used
to vent the system. Make sure the pipe has a pitch towards the surface so it does not accumulate water or condensation
that will close of the airflow to the system.
If a pump dosed system is specified with greater than 18 inches of cover, an additional 2-inch minimum airline must be
extended from the D-box back to a knockout or riser on the septic tank or pump chamber. This maintains the continuity of
airflow from the field.
FIGURE 6: MANTIS SERIES VENTING DIAGRAM
MOUNDEDBACKFILLOVERUNITS
CLEANBACKFILL
FINISHED GRADE
SHRUB

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6.0 System Ventilation Example Drawing
FIGURE 7: MANTIS SERIES 2” BY-PASS LINE, CLOSE UP
SEPTIC
TANK
PUMP
TANK
MIN2" DIABY-
PASSAIRLINE
D-BOX
OUTTOSYSTEM

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7.0 System Care and Maintenance
SEPTIC TANK PUMPING
Do not wait until your system shows signs of failure to have your septic tank pumped out. Waiting can mean
complete clogging and an expensive repair bill. A septic tank filter will gradually slow down effluent flow over 2 to
3 years as a reminder that your tank should be serviced. Filters in residential systems usually need cleaning only
as often as you pump the tank. Call a professional septic tank pumper to inspect your system.
Clean your filter and pump your tank at a minimum of every 3 years.
For a list of septic pumpers in your area, consult the yellow pages of your phone directory.
If your system’s access manholes are at ground level or are clearly marked or mapped, the job of pumping the
tank should be fast and easy. While your tank is being inspected, ask the operator to examine the inlet and outlet
baffles and/or septic tank filter. If anything is broken, have repairs done immediately. The inlet should also be
checked to see if wastewater is continuously flowing into the tank from previously undetected plumbing leaks.
It is not necessary to leave any of the sludge in the tank as “seed.” Incoming sewage contains all the bacteria
needed for proper operation. Acids or bleaches should not be used to clean the tank.
The use of enzymes or other “miracle” septic system additives has not been shown to be of significant value. It
has been observed that some of these additives can actually harm your system. Regular pumping remains the
best insurance against system failure.
Keep accurate records of your system’s inspections and pumping.
DO’S
DO have your tank pumped at least every 3 years by a licensed septic tank pumper (listed in the yellow pages of
your phone directory).
DO practice water conservation. Promptly repair leaky faucets and toilets, run washing machines and
dishwashers only when full, avoid long showers, and use water-saving features in faucets, showerheads and
toilets.
DO divert roof drains and surface water from driveways and hillsides away from the septic system. Keep sump
pumps and household footing drains away from the septic system as well.
DO take leftover hazardous household chemicals to your approved hazardous-waste collection center for
disposal. Use bleach, drain and toilet bowl cleaners, and disinfectants sparingly and in accordance with product
labels.
DON’TS
DON’T drive or park over any part of your septic system. The area over the system should be left undisturbed
with only a mowed grass cover. Roots from nearby trees or shrubs may clog or damage your system.
DON’T put large amounts of cooking oil or grease into the system.
DON’T put non-degradable materials such as disposable diapers, sanitary products, plastic, and cigarettes into
the system.
DON’T put poisons such as gasoline, oil, paint, paint thinner, pesticides, antifreeze, or other chemicals into the
system.
DON’T use commercial septic tank additives. These products usually do not help and some may hurt your
system in the long run.
DON’T wait for signs of system failure. Follow the maintenance advice in this manual.
DON’T use garbage disposals unless your system has been designed according to the requirements of Eljen’s
Design and Installation Guidelines.

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8.0 Recommended Notes on Design Plans
This system is not designed for backwash from a water softener.
This system (is/is not) designed for the use of a garbage disposal.
The Mantis system is not for use under vehicular traffic or for under paving applications.
Organic topsoil layer must be removed from trench and slope extension areas prior to approved fill or Specified Sand
placement. Scarify subsoil prior to select fill or Specified Sand placement.
All Mantis M5Series installations utilize a Specified Sand envelope around the units. 6” minimum underneath, 6”
minimum on the sides, 1” minimum on top, and 8” between the Filter Support Modules. The Specified Sand
specification is listed below: The Specified Sand shall be washed concrete sand meeting the requirements of ASTM
C33 with less than 10% passing a #100 sieve and less than 5% passing a #200 sieve.
SPECIFIED SAND SIEVE REQUIREMENTS
Eljen Mantis M5
Specified Sand Requirements
Sieve Size
Sieve Square
Opening Size
Specification
Percent Passing
(Wet Sieve)
0.375”
9.5 mm
100.0
#4
4.75 mm
95.0 –100.0
#8
2.36 mm
80.0 –100.0
#16
1.18 mm
50.0 –85.0
#30
600 µm
25.0 –60.0
#50
300 µm
5.0 –30.0
#100
150 µm
< 10.0
#200
75 µm
< 5.0
Request a sieve analysis from your material supplier to ensure that
the system sand meets the specification requirements listed above.
Eljen Corporation recommends the use of an appropriate sized septic tank effluent filter for all Mantis systems.
Pumped systems shall have an oversized distribution box utilizing a velocity reduction tee or baffle.
Eljen mandates venting when the system will have more than 18” of cover material as measured from the top of the
unit to finished grade.
After backfill, there should be a minimum of 6” of material as measured from the top of the Filter Support Modules to
the finished grade. The first inch of that fill is specified sand.
Backfill and Finish Grading: Carefully place backfill over the units, followed by a total minimum depth of 6 - 18 inches
of well graded sandy fill; clean, porous, and devoid of rocks, as measured from the top of the Filter Support Modules.
Finish grade must divert surface runoff from the soil treatment area and prevent surface ponding. Protect the system
area from erosion by loaming and seeding or by using other approved methods of erosion control.
Fill material shall meet the Eljen Mantis M5Series Design & Installation Manual requirements. All fill material shall be
clean sand, free of topsoil, directly beneath the STA.
For pumped systems, set pump floats or pump control panels to deliver a maximum of 6 gallons per Mantis 5.2 per
dose cycle or 3 gallons per Mantis 5.1 per dose cycle.
This design complies with and must be installed in accordance with the most current Eljen Design and Installation
Manual.

125 McKee Street, East Hartford, CT 06108 • Tel: [phone] • Fax: [phone]
www.eljen.com
COMPANY HISTORY
Established in 1970, Eljen Corporation created the world’s rst
prefabricated drainage system for foundation drainage and
erosion control applications. In the mid-1980s, we introduced
our Geotextile Sand Filter products for the passive advanced
treatment of onsite wastewater in both residential and commercial
applications. Today, Eljen is a global leader in providing innovative
products and solutions for protecting our environment and
public health.
COMPANY PHILOSOPHY
Eljen Corporation is committed to advancing the onsite industry
through continuous development of innovative new products,
delivering high quality products and services to our customers
at the best price, and building lasting partnerships with our
employees, suppliers, and customers.
© Copyright Eljen Corporation
CORPORATION
Innovative Environmental Products & Solutions Since 1970
Printed in U.S.A. on recycled paper