N.J. Admin. Code § 7:14A-23.25 - Ultraviolet disinfection

(a) The following provisions apply to the design of ultraviolet disinfection (UV) systems:

1. The turbidity and color of the wastewater shall be addressed in the design. Treatment of the influent wastewater prior to the UV units by intermittent sand filtration, or other filtration, as approved by the Department, is recommended. Removable screens, located upstream of the UV unit, are recommended to prevent debris from entering the system.

2. Wastewater shall pass over the UV source in a thin film, so that the maximum depth of penetration is no greater than two inches. The UV contact time shall be dictated by water absorbance and film thickness.

3. A UV intensity sensor shall be installed at the maximum depth from the source with an alarm to alert operators when the UV level falls below acceptable levels. The UV intensity reading shall be displayed by a meter on the control panel. UV sensors shall be properly maintained to insure reliable, accurate readings.

4. The UV unit shall be protected from dust, excessive heat, and freezing temperatures. Adequate ventilation of heat-generating electrical components shall be provided.

i. An alarm system shall be provided to alert the operator of excessive temperatures in the ballast power panel.

5. When utilizing a closed channel UV system two separate units, or one UV unit and another approved form of disinfection, each capable of treating peak flow, shall be provided.

6. Open channel UV systems shall be equipped with a sufficient number of bulbs such that a safety factor of at least 125 percent will be provided. Separate electrical racks shall also be provided to permit maintenance of the system without removing the entire unit from service.

7. Electrical wiring shall be properly sized and the wire covering shall be resistant to UV radiation effects.

(b) UV lamps/sleeves shall be chemically cleaned semi-annually if automatic wipers are present, or three to four times per year if automatic wipers are not present. A clean water supply equipped with a back flow prevention device shall be available at all times.

(c) UV bulbs shall be replaced when dead life occurs (60 percent of initial emission).

Notes

N.J. Admin. Code § 7:14A-23.25