N.J. Admin. Code § 7:14A-23.20

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:14A-23.20 - Rotating biological contactors

(a) Rotating biological contactors (RBC) process may be used when wastewater is amenable to biological treatment.

(b) RBCs shall be preceded by properly designed settling facilities. Efficient grease and scum removal devices shall be provided.

(c) At least four stages shall be provided for secondary treatment applications. Additional stages may be necessary for nitrification and additional BOD removal.

(d) Permanent buildings or covers shall be used to protect the RBC units from sunlight and winter weather. Provisions shall be made for access to the RBC units for observation and repairs. Buildings shall have adequate ventilation, heating, and humidity control, and an internal hoisting device for the removal of the shaft/media assembly. Covers shall be made in removable sections, or have some other means of allowing removal and replacement of the shaft/media assembly.

(e) Drive systems shall be variable speed and may be mechanical or air driven. Air driven systems shall have positive air flow metering and control to each RBC unit.

1. Bearing units shall be self-aligning and shall be located outside of media covers to allow easy access for lubrication and maintenance.

2. A provision for auxiliary power during power outages is required.

(f) Operation and maintenance requirements, including biofilm control, drive train and radial support arm maintenance and repair, and media/shaft repair and replacement, shall be considered in the design and layout of RBC treatment systems. Provisions shall be made for positive flow control to each stage, allowing flexibility in feeding and discharge. Tank depth and configuration shall be such that solids are not deposited in the tank; also, provisions shall be made for draining the tank.

(g) To avoid system failure, flexibility shall be considered in RBC designs. Flexibility can be achieved by having variable rotational speed, the ability to periodically reverse rotational direction, supplemental aeration, or the potential for chemical addition (for example, hydrogen peroxide or chlorine).

(h) Final settling shall provide a detention time of not less than 90 minutes, with a maximum surface settling rate of 600 gpd/sq. ft. and a weir overflow rate not greater than 5,000 gallons per day per linear foot. Higher surface settling and weir overflow rates may be used if the contactor is to be followed by tertiary treatment.

N.J. Admin. Code § 7:14A-23.20