New Jersey Administrative Code › Title 7 - ENVIRONMENTAL PROTECTION › Chapter 14A - NEW JERSEY POLLUTANT DISCHARGE ELIMINATION SYSTEM › Subchapter 23 - TECHNICAL REQUIREMENTS FOR TREATMENT WORKS APPROVAL APPLICATIONS › Section 7:14A-23.26 - Anaerobic sludge digestion and management

Current through Register Vol. 56, No. 14, July 15, 2024
(a) The Department
				does not examine plans covering fire and explosive hazards, heat controlling
				equipment or safety devices and such safeguards are the responsibility of the
				design engineer.
(b) Supernatant
				liquor from sludge digestion tanks shall be returned downstream of the influent
				monitoring points to the raw sewage except that at activated sludge plants, or
				other plants utilizing air as a method of biological treatment, provisions may
				be made for disposal in aeration or reaeration tanks. The wastewater treatment
				facility shall be designed to treat the increased pollutant concentration and
				hydraulic loading of the supernatant or means shall be provided for separate
				treatment.
(c) The minimum diameter
				of all sludge pipes shall be eight inches for gravity flow and six inches for
				sludge pumping.
(d) A fresh-water
				hydrant near the sludge digestion tanks is recommended, and, if present, shall
				be provided with a suitable backflow-prevention device.
(e) Provisions shall be made for the
				introduction of chemicals into all sludge storage or digestion tanks.
(f) Digesters which are proposed to be
				utilized to satisfy stabilization requirements shall be designed to meet the
				requirements for pathogen reduction and vector attraction reduction in
				accordance with N.J.A.C. 7:14A-20.
(g) Sludge digestion tanks shall be in
				conformance with the following:
1. Two or
				more separate units shall be provided, a single digestion tank may be approved
				if the plan and report show all emergency provisions and the proposed use is
				for small installations (design capacity of less than 150,000 gpd) where
				alternate sludge storage is available for emergency use without creating a
				local nuisance, and where pumps and piping are available for such
				emergency.
2. Suitable equipment to
				insure mixing or circulation of the tank contents shall be provided for primary
				digesters.
3. The proportion of
				tank depth to area shall be such as to permit the formation of a reasonable
				depth of supernatant liquor.
4.
				Tank bottoms shall slope toward the withdrawal pipe not less than three inches
				per foot. Flat bottom tanks will not be approved.
5. At least two access manholes of adequate
				size shall be provided in the top of the digester in addition to the gas dome.
				An access manhole in the side wall of the tank is recommended.
6. In the case of multiple tanks, a provision
				shall be made to direct the raw sludge to any tank. In circular tanks the raw
				sludge inlet shall be at a point that is removed from the overflow or
				supernatant draw-offs by a distance at least equal to the radius of the tank.
				In rectangular tanks the raw sludge inlet shall be at the opposite end from the
				overflow and digested sludge draw-off lines.
7. An emergency overflow shall be provided.
				Provisions shall be made for sampling and removal of supernatant from several
				levels.
8. Means shall be provided
				for sampling of digested sludge in accordance with
				7:14A-23.14. Digested sludge
				withdrawal piping shall extend from the center and bottom of circular tanks.
				Means shall be provided for backflushing digested sludge withdrawal piping.
				Adequate transfer piping shall be provided.
9. Unheated primary anaerobic digestion tanks
				will not be approved.
10. The
				mixing of the contents of anaerobic digesters by air is prohibited.