Illinois Administrative Code › Title 77 - PUBLIC HEALTH › Part 905 - PRIVATE SEWAGE DISPOSAL CODE › Section 905.90 - Waste Stabilization Ponds

Current through Register Vol. 48, No. 28, July 12, 2024
General. Waste stabilization ponds may be used if designed and
				constructed in accordance with the following criteria and provided that the
				effluent is discharged in accordance with the requirements of Section
				905.110 (see
				Appendix A, Illustration R as an illustration of these requirements). A septic
				tank sized according to Appendix A, Illustration F or an aerobic treatment
				plant shall precede a waste stabilization pond.
a) Location: A waste stabilization pond shall
			 be located as distant as practical from residences, but in no case closer than
			 the distances shown in Appendix A, Illustration D, and in an area where trees
			 will not interfere with sunlight on the surface.
b) Dimensions. Ponds shall have a length not
			 exceeding 3 times the width.
c)
			 Capacity. When domestic sewage from a septic tank is to be discharged to the
			 waste stabilization pond, the capacity of the pond shall be equivalent to 60
			 times the average daily flow. When preceded by a Class II aerobic treatment
			 plant, the capacity of the pond shall be equivalent to 18 times the average
			 daily flow.
d) Depth. The
			 wastewater depth for a waste stabilization pond shall be uniform and 3 feet to
			 5 feet.
e) Freeboard. A minimum
			 freeboard of 2 feet shall be provided.
f) Embankments. Embankments shall be
			 constructed of impermeable materials and shall be compacted. Embankment slopes
			 shall be in one to 2 (vertical to horizontal) below the water line and one to 3
			 or flatter above the water line. The top width of the embankment shall be a
			 minimum of 2 feet. Embankments shall be seeded or rip-rapped from the outside
			 toe to the high water line. Perennial, low growing, spreading grasses that
			 withstand erosion and can be kept mowed are most satisfactory for seeding of
			 embankments.
g) Inlet. The inlet
			 line shall be placed 12 to 24 inches above the bottom of the pond at a point
			 opposite the overflow structure and shall be supported at no greater than
			 10-foot intervals along its length. It shall discharge at least 10 feet from
			 the water's edge. The inlet line shall be sloped in accordance with Section
			 905.20(g).
h) Outlet. The outlet structure shall be
			 designed to prevent the discharge of floating solids. This shall be
			 accomplished through baffling. The baffle shall consist of a sanitary T or
			 90° elbow. If the 90° elbow is used, a 1/4 inch hole shall be drilled
			 into the top of the elbow to provide an air break. The outlet baffle shall
			 extend 12 inches below the invert of the overflow. The outlet baffle shall be 3
			 to 5 feet from the embankment.
i)
			 Bottom. The bottom of the waste stabilization pond shall be cleared and leveled
			 to the required elevation and shall be lined with an impermeable natural or
			 man-made material. The pond shall be kept free of vegetation that would grow to
			 or above the water surface.
j)
			 Drainage. All surface water shall be diverted away from the waste stabilization
			 pond.