A. Distribution Boxes. Distribution boxes may be installed between a septic tank or aerobic treatment plant and a subsurface seepage system for all gravity flow systems, which do not use serial distribution (See Subsection P. below). Distribution boxes shall be installed level on undisturbed earth (no fill beneath), and shall provide equal distribution of flow to the subsequent disposal system. A single solid header out of the distribution box with T connections to the individual trenches, is allowed provided that all lines are installed level. The solid headers out of the distribution box shall be Schedule 40.
B. Connecting Pipe. The pipe connecting the pre-treatment or primary treatment component to the distribution box and the pipe connecting the distribution box to the subsurface seepage system shall be watertight.
C. Distribution Box Construction. Distribution boxes shall be constructed of a durable watertight, non-corrosive material. They shall be designed to accommodate the necessary distribution lines.
D. Distribution Box Access. Distribution boxes shall be provided with an opening which will serve as a ready access for inspection, cleaning, and general maintenance.
E. Overdig Around Distribution Box. There shall be no connection such as joints, splices or fittings within the area of the overdig around the distribution box.
F. Solid Header. Whenever a distribution box is installed for the purpose of obtaining equal distribution of effluent, a minimum of three-foot solid pipe shall be provided between the distribution box and the drainage tiles.
G. Bedding Material. The bedding material shall be clean stone with no visible mud, silt or clay with particle size ranging from 3/4 inch minimum to 4 inches maximum. The bedding material shall extend the full width of the trench and to a depth of at least 6 inches below the bottom of the distribution line. The bedding material shall extend at least 2 inches above the top of the seepage line. The bedding material shall be covered by geotextile fabric, untreated building paper or other permeable and/or biodegradable material to support the backfill as the laying of the distribution line proceeds. Tar paper, plastic, or other impervious material shall not be used between the bedding material and the earth backfill.
H. Looping Ends of Seepage Field. The ends of a gravel seepage field shall be looped except in serial distribution systems.
I. Acceptable Pipe Materials. All piping located more than 5 feet from the building foundation, used to convey domestic waste to a private sewage disposal system, shall be considered a part of the private sewage disposal system and shall be watertight. This piping shall be ductile iron or plastic pipe. Only plastic pipe shall be used from the septic tank and after the distribution box (where used). Solid piping shall be bedded utilizing up to two (2) inches of coarse graded sand or fine aggregate (1 mm to 1/8 inch in size). Perforated pipe shall be used only as provided in this Ordinance.
J. List of Approved Pipe. Use of plastic pipe and fittings shall conform to the uses designated in Section 905. Appendix A, Illustration C of the Illinois Private Sewage Disposal Code, except that all solid plastic piping used in the private sewage disposal system shall be Schedule 40 or heavier. Piping used to carry domestic sewage under areas such as driveways, roads, or parking areas shall also be sleeved in six (6) inch corrugated metal pipe to prevent crushing or freezing.
K. Pipe Size and Slope. All solid pipes carrying domestic sewage by gravity flow shall have a nominal diameter of at least 4 inches and a minimum slope of 12 inches per 100 feet. Solid header lines used for equal distribution shall be level.
L. Pipe Length. Building sewers in excess of 50 feet in length which carry domestic sewage from the buildings served to the septic tank, or aeration treatment plant shall be provided with at least one clean-out every 50 feet that terminates at grade.
M. Electrical Devices. Any component of a private sewage disposal system which is electrically activated shall be provided with a visible and audible warning device placed within the building served. All electrical devices shall be wired in accordance with the National Electrical Code or a municipal, county or local electrical code, whichever is more stringent. When electrical components are required, it is the responsibility of the private sewage system installation contractor to obtain any necessary electrical permits and to ensure that all electrical components are installed per the applicable electrical code.
N. Abandoned Treatment Units. Septic tanks, cesspools, pit privies, aerobic treatment plants, lift stations and seepage pits which are no longer in use shall be completely pumped. The floor and walls shall be cracked or crumbled so the tank will not hold water and the tank shall be filled with porous granular material or pea gravel. If the tank is removed from the ground, the excavation shall be filled with soil.
O. Distribution Lines. Distribution lines shall be constructed of materials as approved in Section 905.20(f) of the Illinois Private Sewage Disposal Code. The lines shall be perforated. Perforated piping with the exception of 8 inch or 10 inch gravelless seepage systems, or chamber systems, shall have 1/2 to 3/4 inch diameter openings on 3 to 5 inch centers with a minimum of two rows. The openings in the pipe shall be placed downward.
P. Serial Distribution. Serial Distribution is a variation of the seepage field in that it is designed so that each trench in the absorption system is kept full to capacity before overflow to the next trench occurs. Serial distribution has a distinct advantage on sloping terrains. All construction features of the serial distribution system shall be the same as the seepage field, but in addition, shall include the following:
1. Drop Boxes. Adjacent trenches must be connected with a relief line or a drop box arranged in such a manner that each trench, or gravelless pipe or chamber system is completely filled with septic tank effluent to the full depth of the gravel or gravelless pipe or chamber before effluent flows to the succeeding trench.
2. Relief Line. The invert of the first relief line shall be at least one inch lower than the invert of the septic tank or aerobic treatment plant outlet. (See Appendix A: Illustration K of the Illinois Private Sewage Disposal Code.)
3. Solid Header. A minimum three foot solid header shall be provided from the drop box to the start of the perforated tile.
4. Level Trench Bottom. The bottom of each trench and its distribution line shall be level.
5. Earth Cover. There shall be a minimum of 6 inches and a maximum of 24 inches of earth backfill over the bedding material or the gravelless pipe or chambers in the trenches.
6. Installation Along Contours. The trench shall follow the ground surface contours so that variation in trench depth will be minimized.
7. Separation From Tank to Trench. There shall be a minimum of 5 feet of undisturbed earth between the septic tank and the nearest trench.
Q. Location. Location of various components of a private sewage disposal system shall comply with distances specified in Table IV (See Appendix B).
R. Standards for Construction. Soil absorption systems shall meet the requirements in Tables IV, V, VI and IX (See Appendix B).
S. Effluent Filters. Effluent filters shall be tested and listed by NSF International or a laboratory approved by ANSI to determine compliance with the requirements of ANSI/NSF Standard 46 Evaluation of Components and Devices Used in Wastewater Treatment Systems.
(Ord. O-201711-51-031, passed 11-14-2017)