Section Env-Wq 705.02 - Sewage Pumping Station Design Requirements: Wet Well and Dry Well Construction(a) The wet well and the discharge manifold shall be configured to prevent grit from settling back into pump discharge lines of pumps that are not operating.(b) Wet and dry wells including their superstructure shall be completely separated and sealed.(c) Wet well design shall avoid vortexing and air entrainment near the pump suction intakes.(d) A separate sump pump shall be provided in the dry well to remove leakage or drainage, with the discharge above the alarm level of the wet well.(e) Wet wells for sewage pumping stations of greater than 200 gpm capacity shall have either:(1) Division walls so that the station can be kept in operation when work is required in the wet well; or(2) A bypass connection to allow for connection of a pump around the wet well for maintenance, repairs and construction.(f) The effective capacity of the wet well shall be based on the cycle time of the pumps for constant speed operation so as to prevent short cycling of the pumps.(g) The wet well floor shall have a minimum slope of 1 to 1 to the hopper bottom.(h) The horizontal area of the hopper bottom shall be limited to that area required for proper installation and function of the inlet.(i) Wet wells shall be tested prior to operation using exfiltration testing method ACI 350.1 Method HST-NML in effect at the time the wet well is installed, available as noted in Appendix D. Any visible signs of leakage shall be repaired and retested prior to placing the wet well in service.N.H. Code Admin. R. Env-Wq 705.02
(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.