New Hampshire

Design Manual for

GeoMat™ 600, 1200 & 3900 Leaching Systems

April 2017

Patents: www.geomatrixsystems.com –

GeoMat is a trademark of Geomatrix Systems, LLC

SoilAir and HyAir are trademarks of Geomatrix, LLC

Table of Contents

PAGE NUMBER

Introduction 1

GeoMat Sizing Criteria 2

Hydraulic Loading Rates 3

Basic Design Parameters 4

Gravity Distribution Design Parameters 5

Pump to Gravity Considerations 5

Pressure Distribution Design Parameters 5

Excavation Requirements for Trenches 5

Excavation Requirements for Beds 6

Gravity Effluent Transport Lines 6

Pump Systems Force Main 6

Pressure Distribution Manifolds & Laterals 6

Spacing and Maximum Length 7

Zoned Fields and Trenches at Different Elevations 7

Drain Field Cover 7

Maintenance Requirements 8

Rejuvenation Procedure 8-9

GeoMat Schematics 10-13

Distal Port and Flow Equalization Valve Schematics 14

Typical GeoMat System Design Examples 15-18

1

Introduction

The GeoMat™ Leaching System (GeoMat), manufactured by Geomatrix Systems, LLC (Geomatrix) is low profile and designed for maximum treatment and infiltration of wastewater into soil; in certain instances, it is used for subsurface irrigation and nutrient reuse. GeoMat may be utilized with wastewater from a septic tank or pretreatment system (i.e. ATU). The GeoMat comes 6, 12 or 39 inches wide and nominally 1 inch thick.

Water flows into the GeoMat through gravity and/or pressure piping systems. The water is discharged into a highly transmissive core that is covered by a hygroscopic membrane. This combination of the core and membrane draw the water between the application points and uniformly apply the water to the surrounding soil. The soil then draws the water away from the surrounding membrane through capillary action. This results in a more efficient and uniform application of waste water to the soil and minimizes the point loading associated with some other low profile systems. GeoMat can be installed in trench and bed layouts and function with gravity, pump to gravity, and pressure distribution (PD) system configurations.

The combination of a high surface area to void space ratio and shallow placement in the soil profile result in enhanced aeration. Shallow placement in the more biologically active soil horizons additionally enhances treatment of nitrogen, phosphorus, pharmaceutical compounds and other emerging contaminants of concern, Biological Oxygen Demand (BOD), Total Suspended Solids (TSS), viruses and other pathogens.

Geomatrix products are the result of intensive research and development, including in house and third party testing. Test reports are available by contacting Geomatrix.

While some codes do not require the use of PD, treatment units, flow equalization or SoilAir™, Geomatrix, highly recommends the use of these features to enhance treatment and system lifespan, especially where high flows and challenging waste streams are present.

2

TABLE 1

GeoMat Rating and Maximum Dosing

Product

Rating – square foot per linear foot:

Flat (see details on page 10, 11 & 12)

Rating – square foot per linear foot:

Edge (see details on page 13)

Maximum dosing volume gallons per linear foot per dose

GeoMat 600 .5 1.00 0.13

GeoMat 1200 1.00 2.00 0.25

GeoMat 3900 3.25 6.50 0.75

GeoMat Sizing Criteria GeoMat is installed on a 6” bed of ASTM C-33 sand.

GeoMat Leaching Systems shall be sized in accordance with the most current guidance document . Table 1 & 2 should be used as a guide with respect to sizing the system.

Designers can utilize GeoMat system in conjunction with other proprietary treatment systems that will at a minimum always achieve the specified performance standards.

The designer is responsible for specifying the diameter of the gravity and PD pipe (see design criteria for gravity options), the spacing of the orifice holes, and the calculated head loss when PD is used.

Note that vent holes at the ends of laterals are not required.

Sizing a GeoMat system is dependent on consistency and quality of treated effluent.

For all commercial designs with high strength wastewater (BOD5 higher than 200 mg/l, TSS higher than 180 mg/l and FOG higher than 10 mg/l) the designer shall contact Geomatrix or authorized representative for design guidance.

For a system with a design flow in excess of 2,500 gallons per day, please contact Geomatrix or authorized representative for design guidance.

Design software for pump, lateral line, transport pipe, manifold, and additional head losses and ACAD details are available by emailing request to info@geomatrixsystems.com or contacting Geomatrix or authorized representative.

Sample Residential system requiring 300gpd with a 2min / inch percolation rate:

From Table 2 - 2 min/inch percolation rate requires 2 gpd/sqft @ 300 gpd = 150sqft From Table 1 – GeoMat 1200 Flat provides 1.00 sqft/linft: 150 sqft/1.00 sqft/linft = 150 linft of GeoMat 1200 From Table 2 – GeoMat 1200 dosing 0.25 gal/linft/dose: 150 linft x 0.25 gal/linft/dose = 37.5 gal per dose

3

TABLE 2

Hydraulic Loading Rates for GeoMat

GEOMAT HYDRAULIC LOADING CHART (GPD/SF)

Percolation Rate (Min/In)

Residential or Commercial with SoilAir and/or Pretreatment

Residential or Commercial Standard Septic Tank Effluent (STE)

2 3.50 2.00

4 3.41 1.95

6 3.32 1.90

8 3.23 1.84

10 3.14 1.79

12 3.05 1.74

14 2.96 1.69

16 2.87 1.64

18 2.78 1.59

20 2.69 1.53

22 2.60 1.48

24 2.51 1.43

26 2.42 1.38

28 2.33 1.33

30 2.24 1.28

32 2.15 1.22

34 2.06 1.17

36 1.98 1.12

38 1.89 1.07

40 1.80 1.02

42 1.71 0.97

44 1.62 0.91

46 1.53 0.86

48 1.44 0.81

50 1.35 0.76

53 1.26 0.71

54 1.17 0.66

56 1.08 0.60

58 0.99 0.55

60 0.90 0.50

TABLE 2 NOTES:

1. Commercial w/SoilAir indicates a GeoMat installation having an integral SoilAir system installed. SoilAir is a patented advanced leach field aeration system by Geomatrix that enhances treatment and minimizes biomat formation in the leach field disposal area.

2. Commercial w/Pre-Treatment indicates a GeoMat installation having an ATU that achieves a BOD5 and TSS of 30 mg/l or less. 3. Residential w/Air lines indicate a GeoMat installation having the ability to connect a SoilAir blower (s) with previously installed air

lines. 4. Residential w/HyAirTM indicates a GeoMat installation with a prefabricated pump chamber and integral air blower unit hook-up. The

air blower unit would be surface mounted.

4

Basic Design Parameters GeoMat is installed on a 6-inch bed of ASTM C-33 sand. A minimum fill extension meeting NHDES requirements is required along the perimeter of the GeoMat raised leach bed. Maintain a minimum 2:1 side slope beyond the fill extension to original grade. Fill extension is not required for in ground systems. Vents are not allowed on either gravity, pump to gravity or PD GeoMat laterals. The system shall be designed showing an air line for the purpose of rejuvenation if necessary in the future. Air supply lines for typical residential homes of up to 5 bedrooms should be a minimum of 2” SCH 40 PVC. The air line should pitch towards the leaching system and is installed by teeing into the distribution piping at the supply manifold; into the pipe directly upstream and adjacent to distribution box inlet; or into a spare port in the distribution pipe. The air line is then extended to grade, run to a convenient location and capped or connected to a SoilAir blower, if necessary. When a distribution box is utilized, it should be sealed, prior to backfilling, with a sealant suitable for the composition of the distribution box prior to prevent air leakage. A distribution box, specifically designed for SoilAir, is available from Geomatrix. On residential systems, for runs of up to 50 feet, a 2-inch air line is run from the D Box or header to the proposed SoilAir system location. Call Geomatrix or authorized representative for assistance on sizing for other systems. On multi-family home systems, configuring the system into more than one zone is recommended. By splitting the system into two or more zones, one or more zone(s) can be utilized and one or more zone can be rested. Resting allows the zone to dry out, exposing the

biomat to air to help break it down. Zones shall be sized in accordance with NHDES requirements. Lateral separation in two or more different zones shall be a minimum of 6 inches between zones. Preservation of the native soil between trenches and minimizing its disruption and compaction during construction is essential to maintaining soil structure and therefore water and gas movement in the soil around the trenches. Drain field cover shall be a minimum of 6 inches over the top of the distribution lateral and a maximum of 24 inches over the top of the mat. Cover depths between 24 and 48 inches are allowable with the use of SoilAir. GeoMat laterals can be butted together edge to edge when laid flat and in a bed configuration; however, it is best to pull them apart by a minimum of 4 inches edge to edge. Separation distance from the bottom of the GeoMat membrane shall be 24 inches or 18inches from the bottom of the 6 inches of specified sand layer to seasonal high water table, and impervious layer (ledge or hard pan soil) unless otherwise specified by the permit or local approval. Keep the bottoms of the individual GeoMat laterals level. Provide for lateral pipe drainage and maintenance access. Avoid working in soils that are moist or wet as they can easily smear and compact. Scarify the drain field base well before installing components. When first reviewing a site and developing a design, it is best to position the GeoMat laterals parallel to

5

ground surface contours. This will help maximize the hydraulic window and make it easier to keep drain field base elevations uniform. Designing perpendicular to a surface contour will mean that the down gradient end of the drain field trench will be shallow-placed, whereas the up gradient end will be much deeper minimizing the hydraulic window. Within reason, small frequent doses of effluent to the GeoMat are preferred over fewer larger doses; however, rest/re-aeration intervals must be provided for. See Table 1.

Gravity Distribution Design Parameters Gravity GeoMat laterals shall not exceed 50 feet. Only parallel distribution shall be utilized. Laterals for gravity systems can either be 2-inch SCH40 pipe with min. ½-inch perforations or 4 inch SDR35 perforated pipe. It is recommended that a state approved effluent filter be utilized. Distribution box flow equalizers can become clogged and result in unequal flow it is preferable to set pipes at the correct elevation.

Pump to Gravity Design Considerations Pumps should be controlled to provide preprogrammed volumes of effluent to the desired zone(s). The system should record flow and / or dosing information.

Pressure Distribution Design Parameters Pressure System dispersal field dosing should be controlled to provide preprogrammed volumes of effluent to the desired zone(s). The

system should record flow and / or dosing information. Pump systems should be capable of providing the required system Total Dynamic Head plus an additional 24 inches of water column typically. All pressure piping shall be SCH40 pressure pipe and fittings. SCH40 SEWER AND DRAIN PIPE AND FITTINGS NOT ALLOWED. Orifices are typically 1/8 to 1/4 inch I.D. and 1 to 6 feet on center. Each dispersal zone is typically dosed 4 to 12 times per day. Alarm circuit shall be separate from the pump circuit. An event counter and elapsed time run meter for the pump(s) are recommended. The control panel shall be located in an area to allow for convenient servicing and meet local and state electrical codes on placement of control panels. For systems with a design flow of 2,500 GPD or greater, it is recommended that pump panels be equipped with a flow measurement device and/or remote telemetry. It is recommended that a pressure filter (SimTech STF-100) be utilized.

Excavation Requirements For Trenches The soil between the dispersal trenches shall ideally remain undisturbed. If the presence of boulders or other obstacles make trench construction impractical, the entire leach field area may be excavated as necessary, backfilled with ASTM C-33 sand to the design elevation of the bottom of trench and the GeoMat constructed and backfilled with native soil material.

6

Excavation Requirements For Beds The prepared basal area should remain undisturbed to prevent compaction or smearing of the native soils. Backfill to grade with clean fill that meets NHDES requirements, to within 6” of the bed bottom. Place 6” of ASTM C-33 sand to achieve the design elevation of the bed bottom.

Gravity Effluent Transport Lines The effluent transport pipe in gravity systems is typically 4 inches from a Septic Tank or ATU.

Pump Systems Force Main Typical pump systems utilize 1 ½ to 3 inch piping from the pump station or ATU. The actual pipe size will depend upon such factors as distance, pump head, scour velocity, frictional losses and desired pressure at the distal orifices. The force main should be sloped either back to the pump basin and / or toward the GeoMat to clear the line after each dose. In many cases it may be better to slope the force main in both directions. In all cases this is done to prevent freezing in cold weather. An anti-siphon device, such as a weep hole, should be used where any chance of siphoning of the pump tank may occur.

Pressure Distribution Manifolds and Laterals GeoMat distribution manifolds are typically 1 ½ to 4 inch SCH40 PVC. Distribution laterals are typically 1 to 2 inch SCH40 PVC. Size will vary depending on design and site conditions. Flow equalization valves are optional when distribution lines will be at the same elevation and are mandatory if laterals are installed at different elevations. Flow equalization valves are often installed in the pump chamber for easy operation, protection from damage, and protection from freezing.

NOTE: It is recommended to provide a minimum scouring velocity of 2 fps in the laterals. This will minimize orifice clogging, and provide as even distribution of wastewater as possible. However this requires that the treatment system operate at the specified performance standard or orifice clogging can result. Maximum trench length for PD installations to be determined by the site conditions and the need to maintain the +/-10% pressure differential between orifices in the GeoMat laterals. Design software for pump, lateral line, transport pipe, manifold, and additional head losses is available by emailing request to info@geomatrixsystems.com or authorized representative. Designs should account for a minimum of 1 foot and a maximum of 8 feet of head pressure at the distal end of each GeoMat distribution lateral. The lateral piping will be predrilled and GeoGuard™ orifice shields attached and will be available with the GeoMat. The orifice holes will be drilled downward (six o’clock position) and spaced according to the design requirements of the system. SCH40 PVC or equivalent sweep elbows (also called turn ups) or two 45° elbows shall be attached to the distal end of each GeoMat distribution lateral to facilitate maintenance and inspection. A standard 90° elbow should not be used because it will interfere with maintenance activities. The open end (upward end) of the sweep needs to be closed off with either a ball valve or threaded plug or cap. The distal head ports are utilized for measuring and setting distal head on the GeoMat laterals. Distal head ports can also be used for cleaning the laterals if necessary.

7

Spacing and Maximum Length GeoMat when installed on ASTM C-33 sand can be configured as a bed where the sides of adjacent GeoMat are butted together maximizing the treatment area. The laterals can also be pulled apart any distance, edge to edge, from each other. Note that increasing the distance between the rows may reduce the uniformity of the vegetative cover over the system. Maximum trench length for gravity installation should not exceed 50 feet. Actual lengths will vary between sites and will be influenced by site conditions.

Zoned Fields and Trenches at Different Elevations Smaller pumps can be used on larger drain fields and still maintain distal head pressure by utilizing automatic sequencing valves. These valves automatically direct flow to each respective zone or distribution lateral, in a prescribed order. Site conditions may not facilitate installing drain field trenches at the same elevation. In these situations, throttling and distribution valves can be used to provide uniform wastewater distribution; valves also help facilitate flow equalization and cleaning of laterals. Access ports must be installed at the locations of gate valves. Valves can be located in the pump tank or separate valve box.

Drain Field Cover

Drain field cover shall be a minimum of 6 inches over the top of the distribution lateral and a maximum of 24 inches over the top of the mat when installed without SoilAir. If drain field cover is greater than 24 inches over the GeoMat the addition of SoilAir is required to assure proper aeration.

Uniform cover depth over the drain field

results in consistent oxygen transfer to the entire system. The final grade over and around the drain field should direct storm water to sheet flow away from drain field. When backfilling the system, construction staples can be utilized to hold down piping components and mat, but they should not penetrate the top fabric. Care should be exercised to keep a minimum of 6 inches of cover material over the system before operation of low ground pressure equipment. Excavation equipment should not exceed a ground pressure of 5 psi. Operating as well as turning excavation equipment on top of the GeoMat should be avoided. The area directly above and adjacent to any septic drain field should be protected from heavy vehicle traffic and excess weight loads before, during and post construction. This is especially important when using GeoMat. GeoMat systems are located close to the ground surface and therefore susceptible to damage after construction. On all new construction, it is recommended that the proposed drain field location be staked and flagged / fenced to prevent encroachment during home construction. If vehicle encroachment is expected to be a problem after construction, some structure, such as garden timbers, railroad ties, fences or walls should be used to protect the drain field area. The drain field area should be free of debris and planted with grass. Impermeable materials and structures should not be installed or stored over the drain field. Trees and shrubs should be kept a minimum distance of 10 feet from the drain field. Roots from nearby moisture loving trees such as willow, black locust, and red maple may cause problems with roots clogging drain field lateral orifices. Greater setback distances are recommended for these tree species.

Root blocking materials such as ROOTGUARD® or polyethylene sheeting can be utilized.

8

Maintenance Requirements Septic system designs are based on typical wastewater strength, flows and proper maintenance. When septic systems are over used or not maintained, septic systems can fail prematurely. For example: Running or dripping fixtures can also lead to premature leach field clogging because the system cannot dry out and allow the biomat to breakdown. Surface water and groundwater entering septic system components can also overload the system and result in failure. Systems should be final graded to direct surface water away from the septic system components. Septic and pump tanks should be sealed to prevent groundwater infiltration and inflow or located at an elevation above the seasonal high groundwater level. Water softeners and sump pumps should not be discharged to septic systems; unless the septic system is specifically designed for these components and associated flows.

The septic tank and ATU (if present) should be pumped, maintained and operated according to the requirements of the manufacturer and applicable regulatory agency. Effluent filters can help protect septic systems from premature clogging. Maintenance of effluent filter(s) may require a more frequent service interval than that of a septic tank. Service effluent filters on an as needed basis The use of septic systems can vary greatly from installation to installation. The actual wastewater flow and strength has a significant impact on system performance and lifespan. Some uses inherently provide for intervals where the leaching system can rest or, in other words, dry out. This resting results in the organic matter that has accumulated in the system, over time, coming into contact with air.

When organic matter is aerated, it is oxidized or reduced. This reduction of organic matter effectively enhances system performance and lifespan. A SoilAir blower can be added at anytime to enhance the oxidation of accumulated organic matter. Installation when the leaching system is constructed can greatly extend system performance and lifespan when flows and/or waste strength is on the high side. Geomatrix recommends the use of SoilAir whenever the hydraulic flow or organic loading rate will exceed the oxygen flux into the system.

Rejuvenation Procedure In the event of a failure, GeoMat can be rejuvenated by cleaning pressure distribution laterals, if applicable, and through the installation of a SoilAir system; without obtaining any additional approvals.

Even though pre-treated effluent is typically low in BOD and TSS; overtime, accumulation of biosolids or slime can accumulate in GeoMat lateral, pipes and orifices and create uneven wastewater distribution along the lateral. Rejuvenation of pressure distribution systems should incorporate cleaning out the distribution piping if necessary.

In the event of effluent surfacing, water backing up into the septic tank or pump tank alarms, follow the troubleshooting procedure outlined below: First determine the wastewater flow rate to the system by water meter (if available), dose counter and pump calibration (if available) or by pumping the septic tank and determining daily flow. Make certain that the actual wastewater flow rate (GPD) is within the design flow shown on the approved plan. If actual water usage exceeds the allowable design, eliminate excess flow to the system. If wastewater flow to the septic system is within the design value, but the water level in the pump tank is high, or it is taking longer than normal to pump a dose to the field:

9

Check the float switches and pump for proper operation.

If the floats and pump are operating properly, but the dose is taking longer than it should to complete, and it is pressure distribution system, the pressure line and associated pressure filter (if present) should be evaluated for clogging. o If the distal head pressure was

recorded, and it has dropped, clean the pressure filter.

o If the distal head pressure was recorded and it has increased, clean the pressure line by either jetting or bottle brushing the line from the distal head port/cleanout.

o If the distal head pressure was not recorded, clean the pressure lines as a precaution. This should result in a properly functioning distribution system.

If wastewater flow to the septic system is within the design value, but water is still backing up into the septic tank, the GeoMat may have a restrictive biomat, there may be a groundwater issue or the surrounding soil may not be accepting the hydraulic load from the septic system. To determine the cause of the problem:

1. Dig an observation hole with a hand shovel adjacent to the GeoMat in the sand fill. The hole should be dug about a foot away from the GeoMat, to an elevation about two feet below the GeoMat. If this hole is full of water:

Either groundwater is impacting performance or the surrounding soil cannot handle the hydraulic load from the system.

To determine if the problem is groundwater related, go a few feet beyond the perimeter of the sand

fill at a location that is level or higher than the GeoMat. Again, dig an observation hole and determine if groundwater is present at the same elevation as it was in the sand fill. If this is the case, the problem is groundwater related

If there is no groundwater present in this hole, then the surrounding soil is not capable of handling the hydraulic load. i.e. leaking toilets, running faucets or increase in the number of occupants in the home

2. If the observation hole dug a foot away

from the GeoMat is dry,

Dig towards the GeoMat lateral until a portion of the GeoMat is uncovered. Gently clean off the sand from the side of the GeoMat if water begins weeping out of the GeoMat, a restrictive biomat has developed. o When a restrictive biomat is present,

it is a sign that the system has been overloaded with water or organic matter at some point in time.

Septic Systems that have a clogging biomat can typically be rejuvenated utilizing a SoilAir blower to treat and breakdown the biomat and restore the hydraulic capacity of the system. Contact Geomatrix or its authorized agent for assistance in trouble shooting the septic system and septic system rejuvenation process.

10

GeoMat Schematics

11

GeoMat Schematics (continued)

12

GeoMat Schematics (continued)

13

GeoMat Schematics (continued)

14

Distal Port and Flow Equalization Valve Schematics

15

Typical GeoMat System Design Examples Note: These are only for example, for GeoMat Design, Spacing and Maximum Length requirements see pages 4 thru7.

16

Typical GeoMat System Design Examples Note: These are only for example, for GeoMat Design, Spacing and Maximum Length requirements see pages 4 thru7.

17

Typical GeoMat System Design Examples (continued) Note: These are only for example, for GeoMat Design, Spacing and Maximum Length requirements see pages 4 thru 7.

18

Typical GeoMat System Design Examples (continued) Note: These are only for example, for GeoMat Design, Spacing and Maximum Length requirements see pages 4 thru 7.