new rules are official!! effective march 19, 2006 60

NEW RULES ARE OFFICIAL!!

Effective March 19, 2006

60

Design Criteria and Technical Specifications

Rule .35 thru .46These Rules include the design and technical

requirements of the conventional and non-proprietary systems.

Proprietary system requirements are in Product Permits that are authorized by the Rules. The proprietary systems were not put into the Rules because it would require a Rule change anytime a new system/technology or anytime there was a change to any previously permitted technology.

59

420-3-1-.35(1) Engineer Design Required page 45

(a) System > 1,200 gpd

(b) System with “high strength” sewage

- strength higher than that in a typical dwellingsee: sewage & sewage (high-strength) pg 10

- typically kitchen waste from establishments

- not necessarily advanced treatment

58

420-3-1-.35(1) Engineer Design Required page 45 continued

(c) Site characteristics prohibit a conventional system (except shallow placement)

(d) The lot is smaller than minimums in .09* <15,000 sq. ft. with public water* < 40,000 sq. ft. with other than public water (but not less

than 20,000 sq. ft.)* 1 acre for high shrink-swell soils or (1/2 acre for non-

contiguous satellite lots)

(e) Sites that require a mound

(f) Sites that require Modification or Fill

56

420-3-1-.35(1) Engineer Design Required page 45 continued

(g) The REDF is to be smaller than the primary EDF or the EDF includes a driveway or parking area

(g) A holding tank is required

(h) An OSS using complex pumping systems*other than pumping from the pump chamber to a non-pressurized EDF

(j) Sites with percs >120 min/in

55

420-3-1-.36 Design Flow & Wastewater Concentrations page 45

(1) Dwellings – Use Table 1 to calculate Design Flow volume & sewage concentration

(2) Establishments –

(a) Use Table 1

(b) Generally accepted engineering design criteria

(c) Derived from actual water use in comparable developments

*Actual BOD TSS data must be submitted

54

420-3-1-.36 Design Flow & Wastewater 420-3-1-.36 Design Flow & Wastewater Concentrations Concentrations Table 1Table 1

54

Appendix ATable 1

Flow and Organic LoadingGenerator Design Unit Design BOD/TSS Design Flow

lbs/day gpd

DWELLINGS (Rule) 2/Dwelling (8 bedrooms or fewer) per bedroom 0.4 (min) 150 (300 min)9 or more bedrooms to a single system per person 0.2 (min) 75 (min)

ESTABLISHMENTS (guidelines) 3/Airports (not including food service) (not including food service) per passenger 0.02 5Airport per employee 0.05 15Office per employee 0.05 25Marinas with bathhouse or showers or toilets per boat slip 0.15 10Motels no cooking facility per bedroom 0.40 1 20 cooking facility per bedroom 0.80 175Movie Theater (no food preparation) per seat 0.02 4Restaurants per seat 0.2 50RestaurantsInterstate or through highway per seat 0.7 100-180Interstate rest areas per person 0.01 5Service station per vehicle serviced 0.01 10

420-3-1-.41 OSS Area Requirements page 48-49

(1) The OSS area including the EDF and REDF shall be protected

(a) OSS shall not be installed in Texture Group III(3), IVa(4a),IVb(4b) or IVc(4c) soils

* under wet weather conditions

(b) Prohibit vehicular traffic especially when wet

(c) Use excavating equipment with care, prevent side-wall smearing

(d) Remove hydrophytic vegetation within 10 feet of EDF

(e) Grade the site following the SPP 31

420-3-1-.41 OSS Area Requirements page 48-49

(f) Grading requirements for sites not requiring a SPP

(1) Alteration may cause site rating to be changed

(2) Final grading shall divert surface water – prepare for landscaping

(3) Mounds and control fill shall follow PE design

(g) Drainage requirements for an OSS

1. EDF not located in depressed area – minimize surface

2. Divert drains, gutters, etc

3. Properly locate and discharge French Drains

4. Only receives discharge from building sewer 30

420-3-1-.41 OSS Area Requirements page 50

(h) Protection of an OSS shall be accomplished

1. No structure shall be placed over a system component without access provided.

2. Lawn sprinkler systems must use backflow preventions with line 12” above EDF pipe.

3. PE design under playgrounds and athletic fields

4. No location of EDF under driveway (paved or unpaved). PE may design REDF acceptable to LHD.

5. PE may design drives or parking areas over other system components - with load protection and access.

29

420-3-1-.41 OSS Area Requirements page 50

(h) Protection of an OSS shall be accomplished continued

6. Piping of effluent under traffic area must comply with plumbing code.

7. No action shall be taken under this Rule until a complete construction plan, with supporting documentation has been submitted to the LHD and approved.

28

420-3-1-.42 Gravel Field Standard Construction Specification page 50

(1) Minimum standard for rigid pipe is Schedule 40 PVC

(2) Level header and serial distribution type systems

*distribution box may be used

*is required instead of serial distribution in fill on sloping sites

27


(a) Level header system – trench bottoms level within tolerance

*distribution box may be used

*vent tee (no sanitary tee) laid level

1. Invert of header and least 4” below invert of tank outlet

2. Header line shall be level

3. Non-perforated header can not be counted as EDF

26

AOWA:Basic Installer Course 15

Level Header System


Level Header - Other


Level Header System


All Lines Level – Both Planes


Level Header Level Header DetailDetail

Invert of Header shall be Invert of Header shall be at leastat least

4” Below4” Below

invert of septic tank outletinvert of septic tank outlet


(a) Serial distribution following contours may be used

1. Effluent enters by vent tee laid horizontally

2. EDF pipes connected by solid cross-over line

*designed so trench is filled to full design depth

*lines equally dosed

*receiving lines shall be of equal size & square ft.

25


(a)Serial distribution continued

3. Invert of uppermost EDF pipe shall be 8” lower than invert of septic tank outlet and invert of cross-over at least 4” lower than invert of septic tank outlet. Inverts of all crossovers from an EDF trench at equal elevation.

4. Cross over dug no deeper than top of aggregate or top of EDF product in preceding trench with undisturbed block of earth remaining in place for full depth of aggregate/product. Successive crossovers separated as far as possible.

24

Appendix B Figure 2 & 3 pages 138 - 139

23

Appendix B Figure 4 page 140

22

24

Serial DistributionSerial Distribution


Serial Distribution Serial Distribution SystemSystem

Slope

26

Invert of Uppermost Line

MUST BE

AT LEAST 8” LOWER THAN THE

INVERT OF THE TANK OUTLET

8”Undisturbed

Earth


(a)Serial distribution continued

5. Maximum length of EDF 100’ from crossover

(i) One crossover for EDF < = 100’

(ii) Two crossovers minimum for EDF >100”

(iii) Crossovers distributed to minimize short-circuiting

21


(3) Distributions boxes can be used

(a) in lieu of a header

(b) to evenly distribute effluent to more than one field

(c) in lieu of serial distribution

(d) Shall be set on level grade. Non-perforated rigid pipe shall exit the D-box for 5’ on level or equal grade.

(e) distribution box shall be used in lieu of cross-over lines and serial distribution in fill

20

Appendix B - Figure 6 page 141

19


(4) EDF trenches shall meet the following

(a) Bottom width 18” – 36” LHD can approve other widths in special circumstances.

(b) Minimum distance between sidewalls 5’ measured horizontally. On slopes >25% see Table 4 (wider).

(c) Trench bottoms 2” tolerance in 100’.

(d) Minimum depth 12”, Minimum cover 12”

Maximum depth 60”, Must comply with MVS

.76 Soil Depth/Vertical Separation18


17

Appendix B - Figure 4 page

16


(4) EDF trenches shall meet the following continued

(e) Maximum length of EDF trench 100’ except for serial Distribution

(5) EDF pipe in aggregate

(a) Appropriate pipe fittings – ASTM standards.

(b) Pipe elevations within 2” tolerance

(c) Minimum size 4” inside diameter

15


(5) EDF pipe in aggregate continued

(d) Rigid/semi-rigid 2.2 sq.in. exfiltration area per foot of pipe. Pipe with slits – agricultural drain pipe not approved

(e) Perforations turned down

(f) Installed in Board-Approved aggregate

14


(6) Aggregate and cover material

(a) Washed, clean, free from fines, dust, sand, clay

*size range ¼ - 2 ½ inches

*gravel/stone extends 8” below lowest point of EDF pipe to at least level with top of pipe.

*Board can approved other aggregate (scrap tires)

(b) Aggregate covered with untreated building paper, heavy Kraft paper, geotechnical fabric or Board approved. Backfilled with 12” of earth cover. 13


(6) Aggregate and cover material

(c) Plastic sheeting, polyethylene, impervious materials not approved.

(7) All EDF’s lines shall be placed entirely in the native soil or in the fill soil, if required, but not in both.

12

420-3-1-.45 Setback/Separation Distances page 55

(1)Table 5

(2) No underground utility service or main, such as water, electrical, phone, TV, or gas lines may cross over or under an EDF pipe.

(3) An OSS, the EDF, or the REDF area shall not be located in an underground easement

(4) Separation distances from natural or man-made drainage may be reduced with sufficient information

(5) Exceptions for separation for repairs/replacement are found in .89

5

420-3-1-.45 Setback/Separation Distances page 55

4

420-3-1-.46 Additional Setback/Separation Distances for a Large System page 55

(1) Large flow systems with one or more EDF of greater than 600 gpd shall be located the minimum setback required by Table 5, Table 6, and Table 7

(2) Sewer line (not EDF) may cross water line if 18” separation (water line on top). Or encased in approved material for 5’ on each side of the point of crossing.

(3) Collection sewer, force main or supply at least minimum horizontal distances in Table 7.

3

420-3-1-.46 Additional Setback/Separation Distances for a Large System page 55 - 56

(4) Sewer line may cross a storm drain if

(a)18” clear separation

(b) sewer encased for 5’ on either side of the crossing

(5) Sewer line may cross under a stream with 3’ stable cover or line encased for 10’ either side of crossing.

*aerial crossing shall be by ductile iron pipe, with mechanical joints or steel pipe.

*pipe shall be anchored for at least 10’ either side of crossing

2

420-3-1-.46 Additional Setback/Separation Distances for a Large System page 55 - 56

Table 7 page 124

Table 8 page 125

1

420-3-1-.43 EDF Dosing Requirements page 53

(1)EDF’s requiring more than 1,400 linear feet (4,200 sq.ft.) of EDF pipe as determined by the Gravel Field Standard shall be divided into separate and equal EDF’s of not more than 1,000 linear feet of EDF per bed.

(a) Each EDF dosed not more than 6 times per day unless effluent is treated to secondary or better. May be modified by PE with Department approval.

(b) Each dose not greater than 70% unless treated.

(c) Shall use effluent pumps from dosing tank.

11

420-3-1-.43 EDF Dosing Requirements page 54

(d) Effluent pumps shall meet .65 . . .Pumping of Effluent

(e) Use of dosing siphons maybe approved by Board

(f) Use of low-pressure EDF pipe may be used

* LPP placed in 4” diameter EDF pipe

* 8” aggregate under pipe

* PE design with recognized method.

10

420-3-1-.37(1) Gravel Field Standard

EDF Sizing for DWELLINGS page 47

(1) The Gravel Field Standard is the minimum total bottom area for dwellings

Number of bedrooms

X

“Square Feet per Bedroom” in

Table 3 and Table 3a

that corresponds to

the measured or assigned percolation rate

53

Table 3 & 3a page 120-121 (no page number)

52

420-3-1-.37(1)(a) Gravel Field Standard

EDF Sizing for DWELLINGS page 47

Primary EDF shall be a

Minimum EDF size

300 sq. ft.

of the Gravel Field Standard

or

equivalent

Unless designed by an engineer

50

420-3-1-.38 Gravel Field Standard

Reductions for DWELLINGS page 47

(1)Reductions for any disposal medium/device shall be expressed

- as a percent reduction of bottom area in the State-Issued Product Permit

49




48



(1)Reductions for any disposal medium/device shall be expressed


(a) Reduction for advanced treatment is found in Table 2

(b) EDF may be reduced by 33% for 24” deep gravel (percs <120 mpi)

49

Table 2

page 119 (no page number)

47

.38(1)(a) Reduction for advanced treatment for dwellings



(c) Only 1 reduction may be taken per field, except for controlled fill installations

no double dipping with treatment & EDF product

either treatment break or product break

(2) Owners are responsible to repair the system even if a reduction caused the failure.

46

420-3-1-.39 EDF Sizing for ESTABLISHMENTS page 47

(1) EDF sizing based on BOD loading of wastewater that has -

• higher organic concentration (stronger)than the secondary standards, and

• hydraulic loading for wastewater that is weaker than secondary standards

45


(a) Determine average design load in lbs BOD/day from Table 1 (or other literature)

(b) Assume that a septic tank will remove

- 40% of BOD from sewage

- 30% of BOD from high-strength sewage

44

Appendix ATable 1


lbs/day gpd




43

Appendix ATable 1


lbs/day gpd




So a 50 seat restaurant

(Not on an interstate)

50 seats x .2 lbs/day/seat =

10.0 lbs/day BOD

42

septic tank would remove 30% of BOD in high-strength waste so the actual BOD to the field

would be 7 lbs/day

10 x .3 = 3

And

10 – 3 = 7!


To determine size of field based on BOD loading:

c) Divide the BOD load to the field

by the appropriate figure from the column headed

“Field Sizing For Establishments Primary Effluent”

in Table 3 or Table 3a.

41


40

Table 1

Page 118

(no page number)

39



(Not on an interstate) (45 mpi perc)

50 seats x .2 lbs/day/seat = 10lbs

BUT

ST removes 30%!

10 X .3 = 3lbs

and 10lbs – 3lbs = 7lbs

Therefore, the actual BOD/day is

7.0 lbs7.0 lbs / .00080 lbs/sq.ft.=

8750 sq.ft. EDF 38


To determine size of field based on

hydraulic loading:

d) Divide design flow in gpd for the establishment

by column headed “Field Sizing for establishments without/ Secondary Effluent”

in Table 3 or Table 3a.

37

Appendix ATable 1


lbs/day gpd



Table 1

Page 118

(no page number)

36




50 seats x 50 gal/day/seat =

2,500 gal/day

2,500 gal/day / 0.5 gal/sq/ft =

5000 sq.ft. EDF

35




50 seats x 50 gal/day/seat =

2,500 gal/day

2,500 gal/day / 0.5 gal/sq/ft =

5000sq.ft. EDF

(e) The larger field size computed is the

required bottom area

34

So a 50 seat restaurant (Not on an interstate) (45 mpi perc)

50 seats x .2 lbs/day/seat = 10lbs

BUT

ST removes 30%!

10 X .3 = 3lbs

and 10lbs – 3lbs = 7lbs

7.0 lbs

7.0 lbs / .00080 lbs/sq.ft.=

8750 sq.ft. EDF


d) Advanced treatment is required for all establishment design flows over:

• 1,200 gpd of high-strength sewage and

• 4,000 gpd sewage

*Unless it can be shown that the wastewater is already weaker than secondary standards

33

420-3-1-.40 EDF Reductions for Establishments page 48

(1) If the field is large because of high-strength sewage :

the field may be reduced

by treating to secondary standards

and sized using the column headed “Field Sizing for Establishments w/ Secondary Effluent” in

Table 3 or Table 3a

32

420-3-1-.44 Disposal of Effluent from Clothes Washing Machines and Residential Spas page 54

(1)Shall be disposed of by one of following:

(a) Discharge to building drain/sewer

(b) Discharge to a separate EDF

* shall be no less than ¼ of the primary EDF

* primary EDF may be reduced by the amount used for the washer line – not to exceed 1/5 of the total required for the primary EDF before other reductions taken

9


(1)(b) Shall be disposed of by one of following continued:

1. Example 1

500 sq. ft. = original EDF prior to reduction

125 sq. ft. = (500 x .25) washer line

400 sq. ft. = (500 x .20) primary EDF

Total required 525 sq. ft.

8


(1)(b) Shall be disposed of by one of following continued:

1. Example 2

500 sq. ft. = original EDF prior to reduction

125 sq. ft. = (500 x .25) washer line

400 sq. ft. = (500 x .20) primary EDF (reduction from here)

Any additional reduction allowed would come from the 400 sq. ft. primary.

So, if 50% reduction is allowed it would come from the primary 400 sq. ft. leaving 200 sq. ft. for the primary for a system total of 325 sq. ft.

7


(2) Trench bottom areas of the EDF for a spa or similar fixture, at a private dwelling with a 90 gal or greater capacity shall be:

*a minimum of 50% of the EDF

*no reductions for treatment unless PE makes determination and submits actual water use data

6

new rules are official!! effective march 19, 2006 60

Documents

engineer design

sewage sewage highstrength

jjjj sewage highstrength

higher strength

oss area requirements

iiii sewage

definitions page

use table