(A) General requirements. A dosing device is not necessary in all situations but, where used, shall comply with the following requirements.
(1) The dosing chamber shall be watertight and constructed of sound and durable materials not subject to excessive corrosion or decay, vented, and must be designed and constructed to withstand lateral pressures when the tank is empty.
(2) There shall be 1 or more maintenance holes, at least 20 inches least dimension and located directly above the dosing device. The maintenance hole shall extend through the dosing chamber cover to final grade and shall be so constructed as to prevent unauthorized entry.
(3) The dosing chamber shall either include an alternating 2-pump system or have a minimum capacity of 500 gallons or 100% of the average design flow, whichever is greater.
(4) A dosing device must employ an alarm device to warn of failure.
(5) Pumps shall be elevated from the bottom of the dosing chamber to protect the pump from settled solids. The pump, pump controls, and pump discharge line shall be installed so as to be accessible for servicing without entering the dosing chamber.
(6) Electrical installations shall comply with applicable laws and ordinances including the latest codes, rules, and regulations of public authorities having jurisdiction and with
(B) Dosing device for gravity distribution.
(1) Where a dosing device is employed, a pump or siphon shall deliver the dose to the soil treatment system for gravity distribution over the soil treatment area.
(2) For dwellings, the dosing device shall discharge at least 600 gallons per hour, but no more than 2,700 gallons per hour.
(3) For other establishments, the dosing device should discharge at a rate at least 10% greater than the water supply flow rate but no faster than the rate at which effluent will flow out of the distribution device.
(4) If the dosing device is a siphon, a maintenance inspection shall be made every 6 months by the owner or the owner's agent. The siphon shall be maintained in proper operating condition.
(5) If the dosing device is a pump, it shall be cast iron or bronze fitted and with stainless steel screws or constructed of other sound, durable, and corrosion-resistant materials.
(6) Where the soil treatment area is at a higher elevation than the pump, sufficient dynamic head shall be provided for both the elevation difference and friction loss.
(7) Where the dosing device is a pump, an alarm device shall be installed to warn of pump failure.
(Prior Code, Ch. 506 § 13.2)
(C) Dosing devices for pressure distribution.
(1) The dosing device shall be a pump which is cast iron or bronze fitted and with stainless steel screws or constructed of sound, durable, and corrosion-resistant materials.
(2) The pump discharge capacity shall be based upon the perforation discharges for an average head of 1.0 foot for dwellings and 2.0 feet for other establishments. Perforation discharge will be determined by the following formula:
q = 19.65 cd ²
h
h where: q = discharge in gallons per minutes;
c = 0.60 = co-efficient of discharge;
d = perforation diameter in inches; and
h = head in feet
(3) The pump discharge head shall be a least 5 feet greater than the head required to overcome pipe friction losses and the elevation difference between the pump and the distribution device.
(4) The quantity of effluent delivered for each pump cycle shall be no greater than 25% of the average design flow.
(5) A siphon will not be allowed as a dosing device to deliver effluent to a pressure distribution system.
(6) An alarm device shall be installed to warn of pump failure.
(Prior Code, Ch. 506 § 13.3)