OSCAR-II Treatment System Installer Design Manual

Idaho September, 2019

Manufactured by:

Lowridge Onsite Technologies PO Box 1179

Lake Stevens, WA 98258 877 476-8823

info@lowridgetech.com

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Introduction:

1,000 gallon Septic 1,000 gallon pump tank

The OSCAR-II (Onsite Sand Coil Area Recharge) is an at-grade onsite sewage dispersal component dosed with septic tank effluent. The OSCAR-II is comprised of a 12” layer of medium sand media and a series of custom manufactured Netafim Bioline drip tubing coils. The sand media is placed on a prepared soil surface. (See OSCAR-II Installation manual for details). OSCAR-II coils are then placed on the sand media and then covered with another 6” of sand media. No other cover material is needed. To control erosion or inadvertent disturbance from children or animals the sand can be covered with jute mate or cover with a shallow layer of mineral soil. Another option is to spread straw over final cover until vegetative cover takes hold: plant grass seed or other ground cover as soon as possible. See appendix E for more details. The sand/soil interface is the discharge point of the treated wastewater. Vertical separation is measured from the original soil surface prior to preparation and the restrictive layer. If enough soil depth is present, the basal area can be excavated to lower the profile of the OSCAR. Hydraulic loading rates must follow table 4-22, Secondary biological treatment system hydraulic application rates of the Technical Guidance Manual, or as amended. See appendix F for table. Vertical separation must follow table 4-21, of the

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Technical Guidance Manual, or as amended. See appendix G.The septic tank must be an approved septic tank (TGM Section 5.2 Approved Septic Tanks) and IDAPA 58.01.03.007.07. A complex installer may design an OSCAR-II systems according to the standards listed in this manual. The specific drawings for the OSCAR-II foot print for each bedroom design flow rate (1 to 5 bedrooms or up to 350 gpd for non residential commercial designs with residential waste strength) and for each soil group must be followed without deviation. Specific drawings for each soil group, coil model, and sloping or flat site are included in the appendix. If any of the design criteria in this manual needs to be modified or exceeded the system must be designed by a Professional Engineer licensed in the State of Idaho.

Design:

Each OSCAR coil is designed to treat and dispose of 50 or 100 gpd of septic tank effluent, depending on whether an OS-50 or OS-100 OSCAR coil is specified. There are individual drawings and for each design flow rate from 1 to 5 bedrooms on flat and sloping sites, and all soil group (See appendix I).

There are two models of OSCAR coils: OS-50 and OS-100. The OS-50 coils form a 5’ diameter coil, rated at 50 gpd. The OS-100 coils form a 7’ diameter coil, rated at 100 gpd. OS-50 coils can be used in all applications. OS-100 cannot be used in soil groups C-1 or C-2 when the sites are flat.

An OSCAR has two (2) sizing criteria: hydraulic layout and basal area. The hydraulic layout criterion includes the number of coils and how they are to be connected. The basal area refers to the overall foot print of the OSCAR sand/soil interface. Design flow rate for the basil area and hydraulic layout only shall be 150% of the required design flow of IDAPA 58.01.03.007.08. For instance, a three bedroom system is designed at 375 gpd (250 gpd x 150%). The 375 gpd flow rate determines the number of coils and minimal basal area required. To simplify the design process all drawings in this manual are identified by the number of bedrooms.

The specifications for the individual OSCAR foot print in this Installer Design Manual are larger and more conservative than what is found in the OSCAR-II Design Manual. This manual is intended to take a cookie cutter approach without any mathematic calculations required. Maximum slope is 20%.

Hydraulic Layout: Coils are arranged in laterals. Each lateral could be a single coil or a group of coils linked in series between the supply and flush manifolds. The OSCAR coils are timed dosed and flushed automatically.

The standard single family residence OSCAR layouts are prescribed for systems 1 to 5 bedrooms. A 30 gpm, 110 volt, turbine pump (AY Mc Donald pump model 22050E2AJ), LF1P-RF-BLWR or LF1P-RF control panel, and a Lowridge Onsite Technologies headworks (model HWN-.7-RF) are required for

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the standard designs (see appendix B). This pump will perform in a large majority of design applications. The OSCAR must be timed dosed. See “Timer Settings” for details.

All manifolds, supply and flush lines are assumed to be 1” sch 40 PVC. The Installer must reference Table I to insure the supply line length and elevation gain is within the operating capacity of the pump. Design Process:

There are three steps to design an OSCAR-II system:

1. Verify supply line TDH is within tolerance. Refer to Table I. Measure the distance between the pump tank location and the OSCAR. Then, estimate the elevation gain from the pump tank to the OSCAR. Cross reference those two values on Table I. If the intersection of the two values falls within the blue shaded area, the TDH is within tolerance of the pump curve. Go to step 2. If the intersection of the values fall outside of the blue shaded area, stop. The system must be designed by an Engineer.

2.Determine which coil arrangement will fit. Table II & III are a quick reference to determine which coil model should be used. Table II is for flat sites while Table III is for sloped sites. Each table cross references the number of bedrooms to soil group. The intersection of two criteria indicate the over all basal area foot print of a system using either OS-50 coils or OS-100 coils. Select the coil model that best fits the foot print requirements.

3.Select the correct drawing: Appendix I. To select the correct drawing, use the information from step 2 (number of bedrooms and coil model). Each drawing has the top and side view plus the OSCAR dimensions in each soil group. Select the row with the corresponding soil group and the values in that row dictate how to build the OSCAR.

Design example (see appendix J for sample submission package): Assume a 3 bedroom design. There is about 60’ between the tank area and the OSCAR with an elevation lift of about 10’. The site has a slight slope (4%), and there is an area of 2,000 square feet in soil group B2 for primary and reserve areas (approximately 45’ long and 45’ wide). Using Table I we see that a 60’ of run and 10’ of lift is within the blue shaded area of the table. Therefore, the TDH is within tolerance. On table Table III (for sloping sites) we see there are 2 drawings that could be possibilities for this design: 3 bedroom sloping site with OS-100 coils or 3 with OS-50 coils. The OS-100 has a basal foot print of 43’ long by 15.5’ wide. The OS-50 has a length of 57’ and a width of 14’. The OS-50 coils will be a little too long for the area, but the OS-100 will fit length wise and the two widths for the primary and reserve area combined will have a little room to spare. Appendix I drawing for 3 bedroom, sloped site with OS-100 coils should be selected as the design template. The row labeled for soil group B2 has all

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the dimensions for installing the OSCAR dispersal component and how the coils are to be arranged and connected between the two manifolds.

Tanks. Specify which tanks are to be used: concrete, or poly. For designs for up to 4 bedrooms, 1,000 gallon septic and pump chambers are required. See appendix for tank diagram. For 5 bedroom systems septic & pump tanks must be sized and approved according TGM Section 5.2 Approved Septic Tanks and IDAPA 58.01.03.007.07.

Table I: Total Dynamic Head Chart

Note: Installers must verify that the total dynamic head of the supply line falls within the blue shaded areas. Outside the shaded area an Idaho PE must design system.

Elevation lift in feet

Supply Line Length

1” Sch 40

in Feet

20’ 40’ 60’ 80’ 100’ 150’ 200’ 300’

2 4’ 6’ 7’ 9’ 10’ 14’ 18’ 26’

5 7’ 9’ 10’ 12’ 13’ 17’ 21’ 29’

10 12’ 14’ 15’ 17’ 18’ 22’ 26’ 34’

15 17’ 19’ 20’ 22’ 23’ 27’ 31’ 39’

20 22’ 24’ 25’ 27’ 28’ 32’ 36’ 44’

25 27’ 29’ 30’ 32’ 33’ 37’ 41’ 49’

30 32’ 34’ 35’ 37’ 38’ 42’ 46’ 54’

35 37’ 39’ 40’ 42’ 43’ 47’ 51’ 59’

40 42’ 44’ 45’ 47’ 48’ 51’ 56’ 64’

45 47’ 49’ 50’ 52’ 53’ 56’ 61’ 69’

50 52’ 54’ 55’ 57’ 58’ 61’ 66’ 74’

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Table II: Dimensions for flat sites

Note: values in each cell describe the length and width of the basal area. Example: OS-50: 38/20= basal area is 38’ long and 20’ wide.

Flat Site

A= Minimum Shoulder length B&D= Coil/Basal edge separation C= Side slope E= Basal width F= Coil diameter G= Basal length

Flat Site

Soil Groups 1 Bedroom 2 bedrooms 3 Bedrooms 4 bedrooms 5 bedrooms

A1 OS-50: 30/8OS-100: 24/10

OS-50: 36/8OS-100: 24/10

OS-50: 47/8OS-100: 31/10

OS-50: 52/8OS-100: 38/10

OS-50: 69/8OS-100: 45/10

A2a OS-50: 30/8OS-100: 24/10

OS-50: 36/9OS-100: 24/10

OS-50: 47/8OS-100: 31/10

OS-50: 52/9OS-100: 38/10

OS-50: 69/8OS-100: 45/10

A2b OS-50: 30/8OS-100: 24/13

OS-50: 36/9OS-100: 24/13

OS-50: 47/8OS-100: 31/13

OS-50: 52/9OS-100: 38/12

OS-50: 69/8OS-100: 45/12

B1 OS-50: 30/10OS-100: 24/13

OS-50: 36/11OS-100: 24/13

OS-50: 47/10OS-100: 31/16

OS-50: 52/11OS-100: 38/15

OS-50: 69/10OS-100: 45/15

B2 OS-50: 30/13OS-100: 24/21

OS-50: 36/14OS-100: 24/21

OS-50: 47/14OS-100: 31/21

OS-50: 52/15OS-100: 38/20

OS-50: 69/13OS-100: 45/20

C1 OS-50: only31/18.16

OS-50: only40/18.75

OS-50: only51/18.4

OS-50: only66/17.1

OS-50: only92/14.27

C2 OS-50: only39/19.25

OS-50: only51.3/19.5

OS-50: only64.1/19.5

OS-50: only77/19.5

OS-50: only92/19

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Table III: Dimensions for sloping sites (Maximum slope is 20%)

Note: values in each cell describe the length and width of the basal area. Example: OS-50: 40/19= basal area is 40’ long and 19’ wide.

Sloped Site

A= Minimum Shoulder length B= Coil/Basal edge separation, upslope C= Side slope D= Coil/Basal edge separation, downslope E= Basal width F= Coil diameter G= Basal length

Sloping Site

Soil Groups 1 bedroom 2 bedroom 3 bedrooms 4 bedrooms 5 bedrooms

A1 OS-50: 40/10OS-100: 36/15.5

OS-50: 46/10OS-100: 36/15.5

OS-50: 57/10OS-100: 43/15.5

OS-50: 62/10OS-100: 50/15.5

OS-50: 68/10OS-100: 57/15.5

A2a OS-50: 40/10OS-100: 36/15.5

OS-50: 46/10OS-100: 36/15.5

OS-50: 57/10OS-100: 43/15.5

OS-50: 62/10OS-100: 50/15.5

OS-50: 68/10OS-100: 57/15.5

A2b OS-50: 40/10OS-100: 36/15.5

OS-50: 46/10OS-100: 36/15.5

OS-50: 57/10OS-100: 43/15.5

OS-50: 62/10OS-100: 50/15.5

OS-50: 68/10OS-100: 57/15.5

B1 OS-50: 40/10OS-100: 36/15.5

OS-50: 46/10OS-100: 36/15.5

OS-50: 57/10OS-100: 43/15.5

OS-50: 62/10OS-100: 50/15.5

OS-50: 68/10OS-100: 57/15.5

B2 OS-50: 40/13OS-100: 36/15.5

OS-50: 46/14OS-100: 36/15.5

OS-50: 57/14OS-100: 43/15.5

OS-50: 62/15OS-100: 50/15.5

OS-50: 68/13OS-100: 57/15.5

C1 OS-50: 40/15OS-100: 36/21

OS-50: 46/17OS-100: 36/21

OS-50: 57/17OS-100: 43/22

OS-50: 62/19OS-100: 50/23

OS-50: 68/20OS-100: 57/24

C2 OS-50: 40/19OS-100: 36/28

OS-50: 46/22OS-100: 36/28

OS-50: 57/22OS-100: 43/30

OS-50: 62/25OS-100: 50/30

OS-50: 68/26OS-100: 57/31

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Timer Settings:

The OSCAR system must be timed dosed. Timer settings for the OSCAR are short and very frequent (3 minutes and 38 seconds off and 22 seconds on). Because the supply line can drain between doses the “on” times may need to be increased to compensate for the drain back volume. See appendix K.

Pumping Down Hill:

To Avoid siphoning, install an air relief valve on pump line inside of pump tank.

Appendix A

Media: Medium sand.

Appendix B:

OSCAR-II Parts list.

Each OSCAR-II unit will include: • LF1P-RF-BLWR or LF1P-RF control panel • 30 gpm 1/2 hp turbine pump • OS-50 or OS-100 Coils • PVC fittings and drip tubing adapters • HWN-.7-RF, reverse flush headworks* • Solid ½” poly tubing for connections

*When the OSCAR system is preceded with treatment system meeting a treatment level of no more than 15 mg/l of CBOD5 and TSS a manual headworks (HWN-.7-man) may be used.

Appendix C: OS-50 & OS-100 Coil Detail.

OS-50: The OS-50 OSCAR coil is made with 25’ of custom Netafim Bioline with 0.42 gph emitters @ 6” spacing (50 emitters), an average of 2 emitters per sq. ft. Each pre-assembled coil has a minimum area of 25 sq. ft. (5’ x 5’). There must be a minimum of 6” spacing between each coil and a minimum of 6” spacing between any coil and the shoulder edge. Table III contains the

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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” spacing (100 emitters), an average of 2 emitters per sq. ft. Each coil has a minimum area of 50 sq. ft. (85” x 85”). The actual coil diameter is 73”. There must be a 12” minimum spacing between the tubing of differing OS-100 coils and a 6” spacing between any tubing and the shoulder edge.

Illustration VII: OS-100 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.

Appendix D: OSCAR Cover Options.

There may be a desire to cover the OSCAR with something additional to the specified medium sand. Options include:

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• landscaping jute mat held down with staples with grass seed or ground cover plantings

• a thin layer of mineral soil low in organic content (<10% organics) • Sod place sod perpendicular to length of OSCAR-II

Do Not Cover Sand with:

• organic mix (manufactured top soil from compost) • filter fabric

The intent is not to have too much additional cover over the final sand layer. Placing too much cover will inhibit plant root growth. Because the sand is in effect sub-surfaced 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 sand layer is as firm a soil to walk on.

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Appendix E: Tank Drawing

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OSC

AR-

II-Ta

nks

1000

Gal

lon

Tre

atm

ent

Vess

el

1000

Gal

lon

Pre-

cast

Con

cret

e S

ingl

e Co

mpa

rtm

ent

Dis

char

ge T

ank

CRO

SS S

ECTI

ON

PLAN

VIE

W DAT

E: 0

1.29

.201

9

LOW

RID

GE

ON

SITE

TEC

HN

OLO

GIE

S

DRA

WN

BY:

D

BM

DRA

WIN

G ID

: O

S-II-

Tank

s

CK B

Y: D

AVE

LOW

E

SCAL

E: N

TS

PUM

P CO

VERA

GE

HW

A

4" M

IN.

FLO

ATS

UN

ION

S4S5

S1

S3

S2

13

2

HEADW

ORKS

Leng

th

Wid

th

SEE

HYD

RAU

LIC

LAYO

UT

ATTA

CHED

• M

inim

um v

olum

e of

1,0

00 g

allo

ns.

• T

he v

esse

l mus

t be

on

Low

ridg

e O

nsit

e Te

chno

logi

es’

list

of

appr

oved

ves

sels

.•

The

ves

sel m

ust

have

tes

ting

res

ults

fro

m a

n AN

SI c

erti

fied

w

aste

wat

er t

esti

ng f

acili

ty a

nd c

an p

rodu

ce e

fflu

ent

qual

ity

equa

l to

or

less

tha

n 10

0 m

g/l C

BOD

5 an

d 75

mg/

l TSS

.

Appendix F: Hydraulic loading rates

Table 4-22. Secondary biological treatment system hydraulic application rates*

*Idaho Department of Environmental Quality Technical Guidance Manual

Appendix G:

Table 4-21 Intermittent sand filter vertical setback to limiting layers (in ft.)

*Idaho Department of Environmental Quality Technical Guidance Manual

Soil Design SubgroupApplication Rate

(gallons/square foot/day)A-1 1.7

A-2a 1.2

A-2b 1.0

B-1 0.8

B-2 0.6

C-1 0.4

C-2 0.3

Limiting Layer Flow < 2,500 GPD All Soil Types

Flow >or =2,500 GPD All Soil Types

Impermeable layer 2 4

Fractured Rock or very porous layer 1 2Normal high ground water 1 2Seasonal high ground water 1 2

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Appendix H: Designs in soil sub-group C, zero percent slope

In soil sub-group C when the slope is zero, there is a concern that the flow of effluent from the coils to the edge of the basal area will be hindered. For this reason several additional limitations are imposed:

• Only OS-50 coils can be used. • Coils must be placed in the center of the basal area, length wise. • Maximum distance between a coil and the edge of the basal area shall not

exceed 7.25 feet in any direction. • Maximum basal area width is 19.5’. • On flat sites in soil groups C1 & C2 use “Flat Site Guide” in Appendix I.

Appendix I: Design Templates

Soil Group C-1, Flat Site Guides:

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Soil Group C-2, Flat Site Guides:

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1 Be

droo

m F

lat

site

, O

S-50

! 16

2 Be

droo

m F

lat

site

, O

S-50

! 17

3 Be

droo

m F

lat

site

, O

S-50

! 18

4 Be

droo

m F

lat

site

, O

S-50

! 19

5 Be

droo

m F

lat

site

, O

S-50

! 20

1 Be

droo

m S

lope

d Si

te,

OS-

50

! 21

2 Be

droo

m S

lope

d Si

te,

OS-

50

! 22

3 Be

droo

m S

lope

d Si

te,

OS-

50

! 23

4 Be

droo

m S

lope

d Si

te,

OS-

50

! 24

5 Be

droo

m S

lope

d Si

te,

OS-

50

! 25

1 Be

droo

m,

Flat

, O

S-10

0

! 26

2 Be

droo

m,

Flat

, O

S-10

0

! 27

3 Be

droo

m,

Flat

, O

S-10

0

! 28

4 Be

droo

m,

Flat

, O

S-10

0

! 29

5 Be

droo

m,

Flat

, O

S-10

0

! 30

1 Be

droo

m,

Slop

ed,

OS-

100

! 31

2 Be

droo

m,

Slop

ed,

OS-

100

! 32

3 Be

droo

m,

Slop

ed,

OS-

100

! 33

4 Be

droo

m,

Slop

ed,

OS-

100

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5 Be

droo

m,

Slop

ed,

OS-

100

Appendix J Sample Submittal Package

(four pages)

(1 of 4)

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(2 of 4)

Plot Map Sketch

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(3 of 4) Tank Cut Sheet

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Design Template

(4 of 4) Design Template

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3 Be

droo

m,

Slop

ed,

OS-

100

Appendix K: Cold weather timer setting table.

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