6-OSCAR XO2 Design Manual.pdf

OSCAR-XO2 Treatment System Design Manual July, 2024, WA

Manufactured by:

Lowridge Onsite Technologies PO Box 1179

Lake Stevens, WA 98258 877 476-8823 info@lowridgetech.com mailto:info@lowridgetech.com

Treatment tank Discharge tank

Illustration 1

Introduction:

The OSCAR-XO2 treatment system is comprised of two technologies: the XO2 (4 chambers: sep9c, aera9on, clarifier, and pump chambers) and the OSCAR: drip tubing coils, C-33 sand, reverse flush headworks, and control equipment.

Wastewater is collected in the sep9c chamber where gross solids are separated. The waste stream is then aerated in the aera9on chamber. Aerated effluent passes through the clarifier then into the pump chamber. The expected waste strength from the XO2 will be 30 mg/l CBOD5 and 5 mg/l TSS. Effluent is dosed through a 120 mesh disc filter to OSCAR coils, installed in ASTM C-33 sand. Effluent discharged from the coils is treated by the sand prior to infiltra9ng into the receiving soil. The treatment level in the final discharge is expected to reach 2 mg/l CBOD, 1 mg/l TSS, and 36 FC/100 ml, mee9ng Treatment Level A. The XO2 can only be used with the OSCAR.

The C-33 sand/soil interface is the discharge point of the treated wastewater. Ver9cal separa9on is measured from the original soil surface prior to basal area prepara9on and the restric9ve layer. If enough soil depth is present, the basal area can be excavated to lower the profile of the OSCAR.

Design:

Single family residence packages are designated as: OSXO2-240, OSXO2-300, OSXO2-360, OSXO2-450, OSXO2-480, and OSXO2-600 and have the corresponding design flows of 240, 300, 360, 450, 480, and 600 gallons per day. Design flows greater than 480 gallons per day are considered custom and will require design assistance from Lowridge Onsite Technologies, Inc. and an XO2+1 kit. For the standard single family residence OSCAR-XO2 package parts list see the appendix.

The XO2 can only be used with OSCAR coils. All tanks must be approved by Washington Department of Health as wastewater vessels.

The system can be designed in increments of flow up to 3500 gallons per day. The OSCAR has different sizing criteria than the XO2. The XO2 is designed in increments ranging from 500 to 3,500 gallons per day (for reference, see Table 1-2). For non-residential designs see the section “Larger OSCAR-XO2 systems”.

The OSCAR is designed in increments of 62.5 or 125 gallons per coil per day, depending on coil model (see Tables 2 and 3). Consequently, a design for a 7 bedroom system (840 gpd) could incorporate two 1750 gallon, two compartment tanks plus an addition aerator (OX2+1 kit) with 14 OS-50 OSCAR coils (875 gpd).

XO2:

The tanks for the XO2 can be arranged in different formats. One option is to use two double compartment tanks of the same size, either made of polyethylene or concrete, with the following criteria:

Treatment Tank: The partition wall between the first and second compartment of the treatment tank must have either a 4 inch by-pass hole or the bottom of a tee baffle must extend down between 40% to 60% of the liquid depth of the tank.

Discharge Tank: The partition between the first and second compartment of the discharge tank must have a 4 inch by-pass hole located at least 18 inches above the floor of the tank or no more than 27 inches between the bottom of the by-pass hole and floor of the tank. Recommended hight of by-pass hole is 18 inches.

To determine the tank size for design flows greater than 500 gpd, the tanks can be up size proportionally. Example:

Tanks for a 500 gpd design = 1,000 gallons

A 7 bedroom design (120 gpd x 7) is 840 gpd.

840 gpd/500 gpd = 1.68 or 68% increase

Minimum tank size for 840 gpd = 1,000 gal. x 1.68 = 1,680 gallons Therefore, a 1750 gallon, two compartment tank can be used.

For tanks with water tight, structurally sound partitions: for both the treatment tank and discharge tank a double compartment tank with tee baffles can be used (no flow through ports). Flip the discharge tank around so the smaller compartment is first as shown (see Illustration 2). The clarifier chamber is to remain full.

Illustration 2

As the daily design flow rates increase, larger tanks will be needed. It may become necessary to have individual tanks for each chamber or a combination of tanks to meet the volume requirements. For example:

3,000 gpd design flow (refer to Table 1-2).

Septic chamber = 4000 gal. needed, use a 3000 gal. tank + 1000 gal. tank.

Aeration Chamber = 2-1000 gal. tanks.

Clarifier chamber = 2- 1000 gal. tanks.

Pump chamber = 3000 gal. tank + 1000 gal. tank.

In this example, the septic chambers could be connected using standard tee baffles making a two compartment chamber. The aerator chamber could be arranged the same as the septic chambers. Half of the diffusors would be placed in each 1,000 aeration chamber. The clarifier chambers could either use tee baffles or be connected together below the liquid level. The combined pump chambers must be connected below the liquid level.

*Minimum liquid volume needed.

**Local health jurisdictions may require larger tank volumes.

***Table 1-2 is a quick reference guide.

Aerator:

For each 500 gpd design flow one aerator will be needed. Round up the design flow to the next 500 gpd value. For instance, a 600 gpd design flow will need 2 aerators (600 gal. rounded up to 1000 gal. needs 2 aerators).

The aerator box must be installed so that the bottom of the aerator box is at the same elevation or higher than the top of the tank risers, see Illustration 3.

If the site is sloped the aerator box can be buried, upslope from the tanks. The sides of the aerator box lid must not be buried. Aerators can be installed up to several hundred feet away from the diffusors. The line between aerator and diffusors must slope toward diffusors.

Aesthetic concerns should be considered when placing the aerator box.

Place the aerator away from house windows, doors, and areas where people tend to congregate, such as patios areas and barbecues.

Illustration 3

Table 1-2***

Design Flow

Septic Aeration Clarifier* Pump Aerators Suggest tank sizes**

500 gpd 670 330 330 670 1 1,000 gal. treatment, 1,000 gal. discharge

750 gpd 1,000 500 1,000 500 2 1,500 treatment, 1,500 discharge

1500 gpd 2,010 990 990 2,010 3 3,000 treatment, 3,000 discharge

2000 gpd 2,680 1,320 1,320 2,680 4 3k & 1500 treatment & 3k & 1500 discharge

2250 gpd 3,000 1,500 1,500 3,000 5 3k & 1500 treatment & 3k & 1500 discharge

3,000 gpd 4,000 2,000 2,000 4,000 6 use multiple tanks to meet volume needs

3,500 gpd 4,700 2,310 2,310 4,700 7 use multiple tanks to meet volume needs

When multiple aerators are used, multiple diffusors will also be needed.

When multiple tanks are linked together to make up larger aeration tanks, the diffusors must be divider up as equally as possible.

OSCAR Coils:

There are two models of OSCAR coils: OS-50 (62.5 gallons per day) and OS-100 (125 gallons per day). The OS-50 coils form a 5 foot wide single row and the OS-100 coils form a 7.1 feet wide single row. Coils will be arranged in a single line along the contour. Tables 4 and 5 dictate the overall minimum “shoulder” length for the corresponding design flow for each coil model. See appendix for details of OS-50 & OS-100 foot print and specifications. Minimum vertical separation depth is 12 inches in all soil types 1 through 6 with the OS-50 coils and 18 inches with the OS-100 coils.

Coils are arranged in laterals. Each lateral is a single coil or a group of coils linked in series between the supply and flush manifolds. The OSCAR-XO2 coils are timed dosed and flushed automatically.

Table 2 depicts the number of OS-50 coils and laterals required for a given design flow using a Lowridge Onsite Technologies 30 gpm, 1/2 hp, 110 volt turbine pump, model LOT-30. Table 3 depicts the number of OS-100 coils and laterals required for a given design flow using the same pump. The criteria in these tables must be followed. If a deviation is required, contact Lowridge for assistance.

The tables also indicate how much excess head, under the pump curve, is available for supply line elevation lift and friction loss. All manifolds, supply and flush lines are assumed to be 1 inches sch 40 PVC. The designer must calculate the total dynamic head (TDH) for the OSCAR-XO2 supply line. Use the flow rate indicated under the heading “Flush GPM” in Table 2 or 3 for the corresponding design flow and coil model to calculate the friction loss of the supply line. If the calculated TDH is greater than the “Excess TDH” value in Table 2 or 3, call Lowridge for assistance. TDH is calculated by adding the friction loss of the supply line to the elevation lift from liquid level in pump chamber to the OSCAR coils.

Use the following Hazen-Williams formula to calculate friction loss. Always use the Flush Flow Rate valves when calculating fiction loss.

1.85 f=L(Q/K) F= friction loss through pipe in feet of head L= length of supply line in feet Q= Flush GPM K=47.8 (1 inches sch 40 PVC pipe)

TABLE 2

Hydraulic Layout

OS-50 coils

TABLE 3

Hydraulic Layout

OS-100 coils

TABLE 4

Minimum Shoulder Lengths

OS-50

The dimensions in Table 4 represent the minimum required length of the outer shoulder which include coils, spacing between coils, and shoulders. These lengths can be extended to match site conditions. Minimum shoulder spacing and spacing between coils is 6 inches. See illustration below for example of shoulder length.

Design Flow

Total Coils

# of Lats.

Coils per lat.

Dose

GPM

Flush

GPM

Excess

TDH

240 4 4 1 1.4 7.8 50’ 300 5 5 1 1.75 9.75 50' 360 6 3 2 2.1 6.2 50’ 450 8 4 2 2.8 9.2 50’ 480 8 4 2 2.8 9.2 50’ 600 10 5 2 3.5 11.5 50'

Design Flow

Total Coils

# of Lats.

Coils per lat.

Dose

GPM

Flush

GPM

Excess

TDH

240 2 2 1 1.4 4.6 50' 360 3 3 1 2.1 6.9 50’ 480 4 4 1 2.8 9.2 50’ 600 5 5 1 3.5 11.5 50'

Design Flow Minimum Shoulder Length in Feet

240 22.5

300 28

360 33.5

480 44.5

600 55.5

TABLE 5

Minimum Shoulder Lengths

OS-100

The dimensions in Table 5 represent the minimum required length of the shoulder which include coils, spacing between coils, and shoulder. These lengths can be extended to match site conditions. Minimum shoulder spacing is 6 inches. See illustration below for example of shoulder length.

Basal Area:

The basal area is comprised of the total area where the C-33 sand media is in contact with the receiving soil. The minimum required basal area is calculated by dividing the design flow rate by the soil loading rate specified in WAC 246-272A (local codes may have differing loading rates).

Combining Hydraulic Layout and Basal Area Requirements:

To combine the coil layout and the basal area, start with the coil layout.

Refer to Tables 4 or 5 for minimum shoulder lengths. Zero to 5 percent slopes (0-5% slope) are considered flat for basal area calculations and set back considerations. It may be advisable to place the coils on the up side of the basal area when the slope is 2 % or more. On flat sites, the coils should be placed in the center of the basal area. The coils will be arranged in a single line, although the line can be curved to match site contours. Also, no emitter shall be placed within 6 inches of the C-33 sand media shoulder.

On sloping sites (>5 to 20% slope) the coils will be placed parallel to the contour and one edge of the coils must be placed about 12 inches from the upslope basal boundary. There must be at least 6 inches separation added between the drip tubing in different OS-50 coils. With the OS-100 coils the spacing is already included with the 85 inch (7.1 foot) area. Side slopes of the C-33 sand media is at least a 1 to 1 slope. Add the minimum coil length to the side slopes to determine the minimum basal area length. Divide the total basal area square footage by the minimum basal length to calculate the basal area width. Two

Design Flow Minimum Shoulder 240 14’ 2 inches 360 21’ 4 inches 480 28' 4 inches 600 35’ 5 inches inspection ports must be installed: one in the coil area and the other in the basal area as shown. For inspection port construction, see Appendix.

The following are examples of an OSCAR design using OS-50 coils.

FLAT SITE (12-18 inches soil, OS-50)

Example: (refer to illustration above and Table 4).

360 gpd design flow, soil type 4 (0.6 gpd/ft2), flat site

Basal area required = daily design flow ÷ soil loading rate

600 sq. ft. = 360 gpd ÷ 0.6 gpd/ft2

Minimum shoulder length (see Table 4) is 33.5 feet.

Minimum side slopes at 1 : 1 slope @ 6 inches (2 x 6 inches = 1 foot) = 1 foot

Minimum basal length= shoulder length + side slopes

33.5 feet + 1 foot = 34.5 or 35 feet’ Basal area width = required basal area ÷ minimum basal length = 600 sq. ft. ÷ 35 feet = 17.14 or 18 feet

Basal area dimensions for soil type 4 = 35 feet long x 148 feet wide.

If needed, the basal length can be expanded to reduce the basal width.

SLOPING SITE (12-18 inches of soil, OS-50)

Plan View

NTS

Section A

NTS

BASAL WIDTH

ASTM C-33 SAND

COIL

6"

6" 6"

6"

60"6"

PREPARED SOIL SURFACE

4" SLIP CAP

INSPECTION PORT

FLAT SITE

MIN. SHOULDER LENGTH

INSPECTION PORT

A

A

INSPECTION PORT

1" RETURN

1" SUPPLY

BA

SA

L W

ID

TH

OS-300-5

When calculating the required basal area for a sloping site the same process is used as a flat site except for one criterion. The side slope value must include the increased C-33 sand depth due to the sloping site. In order to keep the coils level on a sloping site, additional C-33 sand must be placed under the downslope side of the coil. The greater the C-33 sand hight, the greater the side slope. To calculate the additional C-33 sand depth use the following formula:

Diameter of coil x % slope of site

In the illustration above the 20% slope needs an additional 12 inches of C-33 sand to maintain a level coil network.

inches (diameter of coil) x 20% = 12 inches

The additional 12 inches of C-33 sand needs to be added to the minimum required C-33 C of 6 inches to equate to the 18 inches of C-33 sand on the downslope side of the coil.

Section A

NTS

Plan View

NTS

20% SLOPE

ASTM C-33 SAND

COIL

6"

6" 6"

6"

60"6"

PREPARED SOIL SURFACE

INSPECTION PORT

4" SLIP CAP

18"

MIN. SHOULDER LENGTH

INSPECTION PORT

A

A

INSPECTION PORT

1" RETURN

1" SUPPLY

BA

SA

L W

ID

TH

OS-240-5S

Example:

360 gpd design flow, soil type 4 (0.6 gpd/ft2), sloping site

Basal area required = daily design flow ÷ soil loading rate

600 sq. ft. = 360 gpd ÷ 0.6 gpd/ft2

Minimum shoulder length (see Table 4) is 33.5 inches.

Minimum side slopes at 1 : 1 slope @ 18 inches (18 inches x 2) = 3 feet

Minimum basal area length = shoulder length + side slopes

33.5 feet + 3 feet = 36.5 feet Basal area width = required basal area ÷ minimum basal length

600 sq. ft. ÷ 36.5 feet = 16.43 feet or 16.5 feet

Minimum basal area dimensions for soil type 4 = 36.5 feet long x 16.5 feet wide.

Controller:

The LF1P-RF-ARA control panel shall be used to operate the 9med dosing sequencing of the OSCAR-XO2. Timer se]ngs for the OSCAR-XO2 are short and very frequent (3 minutes off and 30 seconds on). The supply line needs to drain between doses, so the “on 9me” may need to be increased to compensate for filling the supply line prior to each dose.

Set-backs, New construction:

1 The edge of required basal area 2The item is upgradient when liquid will flow away from it upon encountering a water table or restrictive layer.

3The item is downgradient when liquid will flow toward it upon encountering a water table or restrictive layer.

Set-backs, Repairs:

For set-backs on repairs refer to WAC 246-272A, Repairs (maximum extent possible).

Larger OSCAR-XO2 Systems, non-residential:

This section of the design manual will address design flows between 500 gpd up to 3,500 gpd that are considered non-residential. It is assumed that most of the systems designed with greater flows than 500 gpd may be some type of non-residential application. Although, there could be design applications below 500 gpd for a non-residential application. In all non-residential applications features like duplex pumps are recommended. The vast majority of non-residential systems will use one of the two non-residential standard kits: XO2-1500 kit or the XO2-3500 kit.

The XO2-1500 kit is a single zone system that will have a design flow rate equal to or less than 1,500 gpd. The kit comes standard as a duplex pump system with intrinsically safe relays and up to three aerators. See appendix for details.

The XO2-3500 kit is an up to four zone system that will have a design flow rate equal to or less than 3,500 gpd. The kit comes standard as a duplex pump system with intrinsically safe relays, up to 7 aerators, and four zone valves. The control panel for this system will have the capability of using all four zone valves or less by adjusting the parameter settings. See appendix for details.

When the item to be setback1 from is:

Up-gradient2

Down-gradient3

Down-gradient3

Setback distance from property lines, other soil dispersal components, driveways, buildings, ditches or interceptor drains, subsurface storm water infiltration systems, or any other development which would either impede water movement away from the OSCAR or channel groundwater to the OSCAR area

10 feet 30 feet (12-18 inches soil depth)

10 feet (18-24 inches soil depth)

Setback distance from well, suction line or surface water.

100 feet 100 feet 100 feet

The rest of this section will be presented in two parts: firstly, treatment tanks (XO2) and secondly, dispersal (OSCARs).

Treatment Tanks (XO2)

Tank sizes for this section will be upsized proportionally based on a 500 gpd standard. As the design flow proportional increases above 500 gpd, so does the tank volume sizes. It is assumed that tank option #2 will be used (a separate compartment or tank for each segment: septic, aerate, clarifier, and discharge).

Table 1-2 is the basis for upsizing. The number of aerators is also increased the same way.

Aerators

One XP-80 aerator is necessary for every 500 gpd design flow.

Example:

A design flow proposal of 2,200 gpd will need the minimum volumes for the related chamber sizes. First, determine the upsize factor by dividing the design flow by 500 gpd. The upsize factor will then be multiplied by the volume for the 500 gpd volumes for each respective chamber to determine total sizes.

2,200 gpd/500 gpd = 4.4 increase factor

Each chamber size will need to be upsized by a factor of 4.4 or larger.

Septic:

670 x 4.4 = 2,948 gallons Aeration:

330 x 4.4 = 1,452 gallons Clarifier, option #2:

330 x 4.4 = 1,452 gallons Pump tank, (option #2):

670 x 4.4 = 2,948 gallons

This system size could use 4 single compartment tanks: 3,000 gallon septic, 1,500 gallon aeration tank, 1,500 gallon clarifier, and a 3,000 gallon discharge tank.

Aerators needed: 4.4 x 1 aerator= 4.4 or 5 aerators.

OSCAR Design

The OSCAR for the larger design flows are very similar to the single-family residence layouts. Although, there are a few more variables to account for when designing the larger flows.

The larger systems, because of their size, may need to be broken up into multiple zones. Multiple zones may be needed for other reasons like sight constraints or logistical concerns. The largest single zone size must not exceed 1,500 gallons per day or 24 OS-50 coils or 12 OS-100 coils. Zones do not need to be the same size in the same system. All designs must follow this design manual.

The OSCAR portion of the OSCAR-XO2 system has two (2) sizing criteria:

hydraulic layout and basal area. The hydraulic layout criterion includes the number and type of coils, how they are to be connected, and number of zones.

The basal area refers to the overall footprint of the OSCAR sand/soil interface.

Hydraulic Layout:

The hydraulic layout must be completed first before calculating the specific basal area dimensions. Coils are arranged in laterals. Each lateral will be either 1 to 4 coils linked in series between the supply and flush manifolds depending on coil type and design flow. No more than 2 OS-100 can be linked together and no more than 4 OS-50 coils can be linked together. Laterals are linked together to form a zone. No zone can exceed 1,500 gallons per day design flow or 24 OS-50 coils or 12 OS-100 coils.

Factors that affect the size of each zone are the contour, lot size and configuration, elevation change, hydraulic limitations, and design flow requirements. Multiple zones in the same system do not need to be the same size.

Within each zone, all the coils must be on the same plain or contour. For design help call Lowridge for assistance.

Factors for Designing Coil Layout:

Factors for designing the coil layout are: minimum coil inlet pressure, total emitter discharge rate per zone, minimum flush flow rate, and total dynamic head (TDH) of the supply line. Each lateral requires additional flow during the flush sequence. XO2 effluent requires at least 1 fps scouring velocity which equates to

0.8 gpm additional flow per lateral. To be conservative, the flush flow rates listed in this manual are based on 1.6 gpm or 2 fps velocity.

When flushing, it is assumed that the emitters will discharge at the same rate as the dosing cycle. To maintain enough scouring velocity through the lateral there must be enough flow at the inlet to assure a minimum flow at the distal end.

With XO2 effluent, the minimum flow requirement for flushing is the total emitter flow rate plus the flushing flow rate. For easy reference, use Tables 7 and 8.

Example:

One lateral:

1.4 gpm (4 x 0.35 gpm) dosing + 1.6 gpm flush flow = 3 gpm (minimum flow rate) for this one lateral.

Use the minimum flow values for calculating friction loss.

Hydraulic layout design steps

The steps for designing the hydraulic layout are as follows:

1. Determine the total daily design flow rate for the entire system.

2. Determine the number of zones required.

3. Determine the daily flow per zone.

4. Determine the type and number of coils per zone.

5. Determine the number of coils per lateral.

6. Determine the flow rates for dosing, flushing, and minimum flow rate.

7. Calculate the TDH of the supply line.

8. Verify Inlet Pressure.

9. Verify that the flow and head requirements fall under the pump curve.

10. Make potential sizing adjustments.

11. Calculate the basal area and dimensions.

12. Configure the plumbing network.

13. Get a review from Lowridge.

Example

We’ll use the same flow as for the XO2 portion above, 2,200 gpd.

Step 1 Determine daily design flow rate: 2,200 gpd

Step 2 Determine the number of zones required.

2,200 gpd/ max size 1,500 gpd = 1.5 or 2 zones Step 3 Determine the daily flow per zone.

2,200 gpd / 2 zones = 1,100 gpd per zone.

Step 4 Determine the number of coils per zone. Divide the zone flow rate by 62.5 gpd (the daily flow rate per OS-50 coil. For OS-100 coils divid by 125 gpd).

1100 / 62.5 = 17.6 or 18 coils

Step 5 Determine the number of coils per lateral. The number of coils per zone must be divisible by either 1, 2, 3, or 4. See Table 7 and 8 to determine the number of coils per lateral for a single zone. There may be a need to increase the number of coils to arrive at a number of coils to maintain a symmetrical number of coils per lateral. For example, if 17 OS-50 coils were calculated per zone, increase the number to 18. Unless otherwise directed by this manual, DO NOT USE ONE

COIL PER LATERAL.

18 OS-50 coil/3 = 6 laterals per zone

Step 6 Calculate the flow rates for dosing, flushing, and minimum flow rate. Each OS-50 coil discharges at a rate of 0.35 gpm. The flow rate for the zone is calculated by multiplying the number coils by 0.35 gpm. See Table-7.

Flow rate per zone = 18 coil x 0.35 gpm = 6.3 gpm

The flush flow rate is calculated by multiplying the number of laterals per zone by 1.6 gpm. Refer to Tables 7 and 8 for easy reference.

Flushing flow rate = 6 laterals x 1.6 gpm = 9.6 gpm

The minimum flow rate is calculated by adding the dose flow rate plus the flush flow rate.

Minimum flow rate = 6.3 gpm + 9.6 gpm = 15.9 gpm

Step 7 Calculate the TDH of the supply line. The total dynamic head (TDH) is the sum of the friction loss (in feet of head) plus the elevation gain. To calculate the friction loss always use the minimum flow rate (dose + flush). For an example we’ll use a maximum distance to the farthest zone, say 300 feet. You can use tables to determine friction loss or the Hazen-Williams formula: L(Q/K)^1.85, where L is length of supply line in feet, Q is minimum flow rate in gallons per minute, K is the constant for 1 inch such 40 PVC pipe (47). It might be necessary to use

1.25 inch diameter pipe. If so, use 97 for K.

Friction loss = 300(15.9/47)^1.85 = 40.4 feet

Elevation gain is the vertical lift between the discharge tank to the highest zone. Let’s assume 30 feet of elevation gain.

TDH = 40.4 feet (friction loss) + 30 feet (elevation gain) = 70.4 or 70 feet

Step 8 Verify Inlet Pressure. Inlet pressure with lateral containing 1, 2, 3, and 4 coils will be 20 psi or 46 feet of head.

Step 9 Verify that flow and head requirements for the “minimum flow rate” fall under the pump curve. If the system has two different sizes of zones use the flow dynamics of the largest zone to verify the operating capacities. If the zones are at different elevations, use the highest elevation gain for verification. And if there are two different sized zones at different elevation, use the larger zone flow rate AND the highest elevation zone as the elevation lift to verify the operating points.

Minimum flow rate = 15.9 gpm (Step 6)

TDH of zone = 70 feet (Step 7) + Inlet pressure = 46 feet (Step 8) = 106 Feet

The operating point of 106 feet of head and 15.9 gpm flow rate is depicted in two point in this curve. One for a simplex pump system in red and another for a duplex system in blue. The red is above the curve and the blue is below. See Step 10.

Step 10 Make potential sizing adjustments. Unless there is an overriding requirement to change pump sizes, always use the Lowridge pump, LOT-30 provided in the standard kits. If the operating point is above the curve there are a few corrective adjustments that can be made. One is to change the supply and flush pipe diameter size to decrease the friction loss, and thereby reducing the TDH. In our example, the current friction loss with 300 feet of 1” schedule 40 PVC pipe is 40 feet. If the pipe size is changed to 1.25” schedule 40 PVC Pipe the friction loss would drop to:

300(15.9/97)^1.85 = 10.6 feet (For 1.25 inch diameter pipe K=97, 1 inch diameter pipe K = 47)

That could lower the head requirement by 30 feet of head.

Another option is to change the scouring velocity from 2 feet per second (1.6 gpm per lateral) to 1 foot per second (0.8 gpm per lateral). This would lower the flow rate and the friction loss.

With non-residential systems we always use duplex pumps. Having two pumps will allow us to move the operating point to the left on the curve by using both pumps when flushing is called for. Review the pump curve above. Notice the “Duplex” row on the horizontal axis. We use the same curve for simplex pump, but with duplex pumps, when both pumps run simultaneously, we increase the flow by a factor of two while the head does not increase.

Step 11 Calculate the basal area and dimensions. Basal area calculations are simply the design flow (per zone) divided by the soil loading rate. Let’s assume the soil loading rate is 0.42 gallons per square foot per day.

1,100 gal. (Step 3) / 0.42 = 2,619 sq. ft.

The dimensions of the basal area are based on the coil arrangement. The zone has 18 coils (Step 4). Each coil has a nominal diameter of 5 feet. There should be 6 inches between each OS-50 coil. To simplify the math, use a coil dimension of 5.5 feet plus an additional 6 inches on the end.

18 coils x 5.5 feet + 6 inches = 99.5 feet.

On a flat site a minimum of 6 inches will need to be added to each end.

99.5 feet + 1 foot = 100.5 feet

100.5 feet is the minimum length of the basal area.

The basal area width is the total area divided by the basal length.

2619 sq. ft./100.5 feet = 26.06 say 27 feet

Each zone will be sized for:

2619 sq. ft.

100.5 feet long 27 feet wide

On a sloping site an adjustment needs to be made for the additional sand under the downslope side of the coils. Multiple the diameter of the OS-50 coil in inches (60) by the percentage of slope as a decimal (20% =0.2).

20% (0.2) x 60 inches = 12 inches Add 12 inches to the downslope sand depth.

6 inches + 12 inches = 18 inches.

18 inches x 2 = 3 feet

99.5 feet shoulder length + side slopes = 102.5 feet minimum basal length

2619 sq. ft./102.5 feet = 25.6 or 26 feet

Step 12 Configure the plumbing network. This portion of the process combines all the headworks, pumps, and controls. To simplify the process Lowridge has introduced two additional standard kits: XO2-1500 and XO2-3500-X. The XO2-1500 is for a single zone up to 1,500 gpd design flow rate. The XO2-3500-X is for up to 3,500 gpd with up to 4 zones.

At this point of the design process the correct XO2 kit is identifiable. An XO2-1500 is to be used when:

• the design flow is 1500 gpd or less, and

• only one zone is specified.

An XO2-3500-X is used when:

• when multiple zones are specified.

• the “X” (XO2-3500-“X”) represents the number of aerators. a 2,200 gpd design flow would need 5 aerators: XO2-3500-5.

Once the configuration is completed, send a pdf file of the design to Lowridge for review.

Lowridge provides sample drawings in both pdf and DWG formats for the coil arrangements, pumps, headworks, and zone plumbing.

Pumps

All the pumping systems are intended to be able to drain to prevent the potential of freezing. Lowridge provides “hose and valve assemblies” that allow the system to drain from the headworks back into the tank, access to the plumbing within the tank riser, and prevents one pump from back feeding onto the other when duplex pumps are used. Below is an illustration of a duplex pump arrangement and detail of the hose and valve assemblies.

Illustration 2: Duplex Pumps Illustration 4: Hose & Valve Assembly

Illustration 5: 3 zone headworks

Headworks

The headworks for the larger design flow OSCAR-XO2 will have the same features, although in differing quantities and locations. The headworks will be housed in 2 or more valve boxes. The first box will always have three pressure gauges, one disc filter, one flow meter, and 4 solenoid valves. The second valve box will house the “zone” valves marked “C1”, “C2”, … corresponding to the number of zones. Four zone valves is standard with the XO2-3500.There may be a third valve box or it could be combined with the second box. Either way the function will be the same. The third box, as shown here, depicts three flush lines with a check valve on each flush line. The check valves allow each zone to be individually flushed without the flow of liquid back feeding any of the other zones.

They are incorporated here in boxes with unions for future servicing or replacement.

Step 13 Get a review from Lowridge. Send a pdf file of the design to Lowridge for review.

Custom Quote

There will be occasions when the standard kits (XO2-1500 or XO2-3500) will need to be modified. In that case, Lowridge is to be contacted early in the design stage to help create a Quote that will outline what will be supplied in the custom package. Lowridge will start a file on each design in the form of a Quote. The quote will have the basic information to provide a complete and accurate package for installation.

The package will include the control panel for operation of the alarm circuit, the pumps, solenoid valves, aerator(s), and float switches. Other items will be the headworks with additional installation diagrams, the pump(s), floats switches, coils, hose & valve assemblies, and a number of miscellaneous fittings and adapters. Basically, the parts that are NOT unique to this kit: tanks, pipe, sand, electrical splice boxes, risers and lids.

Table 7 is an easy reference which shows the flow ranges for zones sized from 625 gpd to 1500 gpd or from 10 coils to 24 coils per Zone when using OS-50 coils. Table 8 shows the same data for OS-100 coils. Each flow range indicates the number of coils per lateral total number of laterals, dose flow rate, flush flow rate, and the minimum flow rate (dose and flush flow rates combined).

Table-7* 24 Coils per Zone 1,500 GPD OS-50 Coils

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 12 8.45 gpm 19.2 gpm 27.65 gpm

3 8 8.45 gpm 12.8 gpm 21.25 gpm

4 6 8.45 gpm 9.6 gpm 18.05 gpm

22 Coils per Zone 1,375 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 11 7.7 gpm 17.6 gpm 25.3 gpm

21 Coils per Zone 1,312 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

3 7 7.35 gpm 11.2 gpm 18.55 gpm

20 Coils per Zone 1,250 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 10 7.0 gpm 16.0 gpm 23.0 gpm

4 5 7.0 gpm 8.0 gpm 15.0 gpm

18 Coils per Zone 1,125 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 9 6.3 gpm 14.4 gpm 20.7 gpm

3 6 6.3 gpm 9.6 gpm 15.9 gpm

16 Coils per Zone 1,000 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 8 5.6 gpm 12.8 gpm 18.4 gpm

4 4 5.6 gpm 6.4 gpm 12.0 gpm

15 Coils per Zone 937 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

3 5 5.25 gpm 8.0 gpm 13.25 gpm

14 Coils per Zone 875 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 7 4.9 gpm 11.2 gpm 16.1 gpm

*XO2-1500

Table-8**

12 Coils per Zone 750 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 6 4.2 gpm 9.6 gpm 13.8 gpm

3 4 4.2 gpm 6.4 gpm 8.6 gpm

4 3 4.2 gpm 4.8 gpm 9.0 gpm

10 Coils per Zone 625 GPD

Coils per Lateral Number of Laterals

Dose Flow Rate Flush Flow Rate Minimum Flow Rate

2 5 3.5 gpm 8.0 gpm 11.5 gpm

OS-100 Coils

12 Coils per Zone

1500 GPD

Coils per Lateral

Number of Laterals

Dose Flow Rate

Flush Flow Rate

Minimum Flow Rate

Excess Head

2 6 8.4 gpm 9.6 gpm 18 gpm 60 Feet

OS-100 Coils

10 Coils per Zone

1250 GPD

Coils per Lateral

Number of Laterals

Dose Flow Rate

Flush Flow Rate

Minimum Flow Rate

Excess Head

2 5 7.0 gpm 8.0 gpm 15 gpm 60 Feet

**XO2-3500

Appendix

OS-50: The OS-50 OSCAR coil is made with 25 feet of custom Netafim Bioline with 0.42 gph emitters @ 6 inches spacing (50 emitters), an average of 2 emitters per sq. ft. Each pre-assembled coil has a minimum area of 25 sq. ft. (5 feet x 5 feet). There must be a minimum of 6 inches spacing between each coil and a minimum of 6 inches spacing between a coil and the shoulder edge. Table 4 contains the minimum shoulder length for a given design flow. The “shoulder length” is the total minimum distance from the outside shoulder edge of the first coil to the opposite end shoulder of the last coil. This dimension includes all the coils, coil spacing, and shoulder spacing on each end.

OS-100: The OS-100 OSCAR coil is made with 50’ of custom Netafim Bioline with 0.42 gph emitters @ 6 inches spacing (100 emitters), an average of 2 emitters per sq. ft. Each coil has a minimum area of 50 sq. ft. (85 inches x 85 inches). The actual coil diameter is 73 inches. The coil bracket is 85 inches long. When the coil

OS-100 Coils

8 Coils per Zone

1000 GPD

Coils per Lateral

Number of Laterals

Dose Flow Rate

Flush Flow Rate

Minimum Flow Rate

Excess Head

2 4 5.6 gpm 6.4 gpm 12 gpm 60 Feet

OS-100 Coils

6 Coils per Zone

750 GPD

Coils per Lateral

Number of Laterals

Dose Flow Rate

Flush Flow Rate

Minimum Flow Rate

Excess Head

2 3 4.2 gpm 4.8 gpm 9.0 gpm 60 Feet

OS-100 Coils

5 Coils per Zone

625 GPD

Coils per Lateral

Number of Laterals

Dose Flow Rate

Flush Flow Rate

Minimum Flow Rate

Excess Head

1 5 3.5 gpm 8.0 gpm 13.0 gpm 60 Feet brackets are aligned end to end the minimum coil spacing is automatically achieved. There must be a 12 inches minimum spacing between the tubing of differing OS-100 coils and a 6 inches spacing between any tubing and the shoulder edge. Table IV contains the minimum shoulder length for a given design flow. The “shoulder length” is the total minimum distance from the outside shoulder edge of the first coil to the opposite end shoulder of the last coil. This dimension includes all the coils, coil spacing, and shoulder spacing on each end. See illustration below.

OS-100 Coil Detail:

The OS-100 OSCAR coil contains 100, 0.42 gph Netafim emitters in a 50 sq. ft. foot print. Emitter concentration is 2 emitters per sq. ft. Design flow for each OS-100 is 100 gpd.

Sample Coil layouts

300 gpd 360 gpd

480 gpd

Headworks: HWN-.7-RF

• ¾ inches Arkal disc filter, mesh, 130 micron

• ¾ inches Arad flow meter

• Three oil filled pressure gauges (0-100 psi)

• 5 Netafim normally closed solenoid valves (Model 80)

OSCAR-XO2 Parts list (500 gpd).

ASTM C-33 SAND

COIL

6"

6" 6"

6"

60"6"

PREPARED SOIL SURFACE

4" SLIP CAP

INSPECTION PORT

Section A

NTS

BASAL WIDTH

FLAT SITE

Plan View

NTS

1" RETURN

1" SUPPLY

MIN. SHOULDER LENGTH

INSPECTION PORT

A

A

INSPECTION PORT

BA

SA

L W

ID

TH

OS-240-5

ASTM C-33 SAND

COIL

6"

6" 6"

6"

60"6"

PREPARED SOIL SURFACE

4" SLIP CAP

INSPECTION PORT

Section A

NTS

BASAL WIDTH

FLAT SITE

Plan View

NTS

MIN. SHOULDER LENGTH

INSPECTION PORT

A

A

INSPECTION PORT

1" RETURN

1" SUPPLY

BA

SA

L W

ID

TH

OS-300-5

ASTM C-33 SAND

COIL

6"

6" 6"

6"

60"6"

PREPARED SOIL SURFACE

4" SLIP CAP

INSPECTION PORT

Section A

NTS

BASAL WIDTH

FLAT SITE

Plan View

NTS

MIN. SHOULDER LENGTH

1" RETURN

1" SUPPLY

BA

SA

L W

ID

TH

OS-360-5

INSPECTION PORT

INSPECTION PORT

A

A

Each OSCAR-XO2 unit will include:

• LF1P-RF-ARA control panel

• LOT-30, 1/2 hp, 120 volt pump

• Hi-Blow Aerator, HB-80 (80 liter/minute)

• Hi-Blow diffusers

• OS-50 or OS-100 Coils

• PVC fittings and drip tubing adapters

• HWN-.7-RF automatic headworks

• Solid ½ inches poly tubing for connections

• 2 float switches

OSCAR-XO2+1 Parts list (501-1,000 gpd).

Each OSCAR-XO2+1 unit will include:

• LF1P-RF-ARA control panel

• LOT-30, 1/2 hp, 120 volt pump

• Hi-Blow Aerator2 (2), XB-80 (80 liter/minute)

• Hi-Blow diffusers (4)

• OS-50 or OS-100 Coils

• PVC fittings and drip tubing adapters

• HWN-.7-RF automatic headworks

• Solid ½ inches poly tubing for connections

• 2 float switches

OSCAR-XO2 coil Connections

Manifolds and supply lines are 1 inches Sch 40 PVC

Manifold and blank tech line adapter and connection.

Blank tech liner and Bioline connection with internal coupling

Inspection ports.

OSCAR Cover Options.

There may be a desire to cover the OSCAR with something additional to the specified ASTM C-33 sand. The intent is not to have too much additional cover over the final C-33 sand layer that would prevent the sand from accessing oxygen from the atmosphere. Placing too much cover will inhibit plant root growth. Because the C-33 sand is sub-surface irrigated, grass and other ground cover will grow rapidly, forming a firm protective cover over the OSCAR. At the end of the first growing season the C-33 sand layer will be as firm as native soil to walk on.

Options include:

• Landscaping jute mat with grass seed or ground cover plantings

• A thin layer of mineral soil low in organic content (<10% organics)

• Thin layer of crushed or washed rock for wind erosion protection.

• Thin layer of bark to wood chips.

• Aggregates the size of rip-rap (5-6 inch diameter) can be “placed” on the OSCAR for protection from deer or elk traffic. These larger sized aggregates must be placed, not dropped, on the OSCAR to prevent breakage of piping and other materials.

• Wire mess can be installed over the sand to prevent erosion and allow for grass to grow.

Do Not Cover C-33 Sand with:

• organic mix (manufactured top soil from compost)

• filter fabric

LOT-30 pump curve: