Section Env-Wq 713.01 - Activated Sludge: General Design Requirements(a) The activated sludge process and its various modifications shall be used only where sewage is amenable to biological treatment.(b) WWTP design shall provide for multiple aeration tanks capable of passing peak hourly flow with one unit out of service and of meeting process requirements with all units on line.(c) Where the WWTP design provides for all return sludge to be mixed with the raw sewage or primary effluent at one location, then the mixed liquor flow rate to each aeration unit shall be equal by means of a controlled distribution structure.(d) All activated sludge designs shall include provisions for the control of bulking sludge and filamentous micro-organisms.(e) Return sludge equipment shall comply with the following:(1) The return sludge rate shall be varied by means of variable speed motors, drives, or timers. All designs shall provide for flexibility in operation. The return sludge rate shall be at least 100 percent of average annual influent design flow and sufficient to maintain design MLSS at maximum day flow rates;(2) The maximum return sludge capacity shall be obtained with the largest pump out of service; and(3) A method for observing, sampling, and controlling return activated sludge flow from each settling tank shall be provided.(f) Waste sludge facilities shall comply with the following: (1) In addition to capacity required for return sludge pumping, waste sludge pumping facilities shall be provided with a minimum capacity not less than 25 percent of design average rate of wastewater flow, or a minimum of 10 gpm, whichever is larger. Waste sludge pumps shall function satisfactorily at 0.5 percent of design annual average wastewater flow;(2) Waste activated sludge may be discharged to the primary settling tanks, sludge digestion tanks, sludge thickening or dewatering processes, storage tank or any practical combination of these units; and(3) A method for observing, sampling and controlling waste activated sludge flow shall be provided.N.H. Code Admin. R. Env-Wq 713.01
(See Revision Note at chapter heading for Env-Wq 700) #8590, eff 3-25-06
Amended byVolume XXXIV Number 46, Filed November 13, 2014, Proposed by #10693, Effective 10/15/2014, Expires10/15/2024.