New York Codes, Rules and Regulations › Title 10 - DEPARTMENT OF HEALTH › Chapter - APPENDICES › Appendix 75-B › Section 75-B.2 - Activated carbon treatment systems

Current through Register Vol. 46, No. 28, July 10, 2024
These systems consist of filtration equipment which use
				  activated carbon to remove organic chemicals from individual water supplies.
				  They also may be used to improve the aestetic quality of drinking water. These
				  systems are normally installed between the water source and the first point of
				  use in the water distribution system.
(a) When an activated carbon filter unit is
				installed to treat an individual water supply containing organic chemicals, it
				must meet all of the following conditions:
(1) The units are installed in-line and serve
				the whole household. Faucet or undersink units shall not be used for the
				removal of organic chemicals.
(2)
				The treatment unit must be capable of processing water at a flow rate of at
				least five gallons per minute (gpm). Flow rates may be reduced if additional
				pressurized storage is provided after the treatment unit to insure the system
				will provide at least five gpm of treated water to the household continuously
				for a minimum of 20 minutes.
(3)
				The maximum application rate shall be 10 gpm per square foot of activated
				carbon surface area. Flow rates shall be controlled by a flow limiting
				device.
(4) The minimum empty bed
				contact time shall be three minutes. This should be accomplished with at least
				two filter units of equal size placed in series.
(5) Only virgin carbon shall be used. The
				cylinder should be recharged at a point outside the residence and the spent
				activated carbon properly disposed of by the vendor.
(6) Disinfection must be provided after the
				activated carbon unit. The preferred method of disenfection is an ultraviolet
				unit with a minimum rating of five gpm. The unit shall have a fail-safe device
				that detects the intensity of the ultraviolet light and automatically shuts
				down the system when the intensity decreases to below the minimum effective
				level specified for the unit. A manual or automatic wipe must be provided. An
				alternate method of disinfection would be sodium hypochlorite. If sodium
				hypochlorite is used, contact time adequate to eliminate, pathological
				organisms must be provided after the point of injection and prior to
				consumption. The local health unit having jurisdiction may allow the use of
				activated carbon units without disinfection upon the adoption of a formal
				procedure for the approval of treatment systems installations, and notification
				to homeowners of the need for disinfection.
(7) Treatment units capable of backwashing
				shall only use treated water for that purpose. Backwashing should be at a
				minimum flow rate of 10 gpm for at least two minutes. The backwashing must be
				accomplished in a manner that does not create a cross-connection. The
				wastewater shall not be discharged to the ground surface but may be discharged
				to a septic system.
(8) All
				components of treatment units must safely withstand the highest water pressure
				in the system.
(9) The following
				must be provided:
(i) A flow meter to record
				total flow.
(ii) Sampling taps for
				raw, partially treated and treated water.
(iii) adequate valving to isolate the various
				components, and for backwashing of filters.
(iv) Only nontoxic materials and
				coatings.
(v) Ease of access to all
				components.
(vi) Prefiltration
				where appropriate to remove turbidity and bacteria.
(vii) Pressure gauges before and after the
				activated carbon unit.