Illinois Administrative Code › Title 77 - PUBLIC HEALTH › Part 905 - PRIVATE SEWAGE DISPOSAL CODE › Section 905.80 - Re-circulating Sand Filter

Current through Register Vol. 48, No. 28, July 12, 2024
a)
			 General. The re-circulating sand filter system (Appendix A, Illustration O)
			 consists of a septic tank, recirculation tank, open sand filter and flow
			 splitter. It may be used provided that the effluent is discharged in accordance
			 with the requirements of Section
			 905.110.
b) Septic Tank. The septic tank shall be
			 sized and installed as described in Section
			 905.40.
c) Re-circulation Tank. The re-circulation
			 tank volume shall be 500 gallons, and the tank shall be equivalent in strength
			 and materials to the septic tank as provided in Section 905.40. No baffles are
			 necessary. An access manhole, as described in Section
			 905.40(b)(7),
			 shall be provided for pump maintenance or replacement.
d) Sand Filter. The sand filter shall be
			 sized at one square foot of filter surface for every 3 gallons per day of
			 domestic sewage flow. Appendix A, Illustration P has a size chart for
			 residences based on numbers of bedrooms. Unless otherwise stated in Appendix A,
			 Illustration P, the sizes shown are required. The filter media shall comply
			 with requirements of Section
			 905.70(e) and (f)
			  and shall be 30 inches in depth.
e) Bedding Material. The bedding material for
			 the collection lines shall be the same as that in a buried sand filter. The
			 coarse gravel shall be 3/4 to 21/2 inch diameter, and the pea gravel shall be
			 from 1/8 to 3/8 inches diameter. A minimum of 2 inches of coarse gravel shall
			 be placed on the excavation prior to placement of collection lines.
f) Distribution and Collection Lines. The
			 collection lines shall be constructed of materials as approved in Section
			 905.20(f)
			 and shall be 4 inches inside diameter perforated piping laid with perforations
			 facing downward. The distribution piping shall have an inside diameter of 11/2
			 inches. The perforated pipe shall have 1/2 to 3/4 inch diameter openings on
			 3-inch to 5-inch centers with 2 rows at 120° from each other. Distribution
			 piping shall be spaced on 3-foot centers and shall be located a minimum of 11/2
			 feet from sidewalls.
g) Pumps. The
			 pump shall be a submersible pump designed for corrosive liquids and shall have
			 a capacity of 15 to 25 gallons per minute at the 10-foot total dynamic head
			 (TDH). The pump shall be controlled by a time clock that can be set to activate
			 the pump at one hour or longer intervals. Pump shut-off shall be controlled by
			 a low level float switch that allows the entire contents of the re-circulation
			 tank to be pumped during each pump cycle. A high level float switch shall be
			 provided that energizes a visible and audible alarm to indicate pump failure or
			 malfunction. (See Appendix A, Illustration Q.)
h) Flow Splitter. The flow splitter shall be
			 designed so that re-circulation rates can be controlled between no
			 re-circulation and a 5:1 re-circulation ratio. An example of one type of
			 splitter is shown in Appendix A, Illustration O.