Section Env-Wq 715.04 - Dechlorination Systems(a) Dechlorination to reduce free and combined chlorine residuals in WWTP effluent, if required by permit, shall be by use of sulfite salt solutions.(b) Dechlorination systems shall: (1) Be sized to chemically neutralize 5 parts per million total residual chlorine at all flows;(2) Be of the positive displacement type;(3) Include storage of sufficient volume to provide for dosing at the anticipated maximum dose rate at design annual average flow for 15 days;(4) Include a redundant dechlorination feed pump;(5) Provide thorough hydraulic or mechanical mixing at the point of sulfite injection;(6) Provide a flow proportional feed forward control system;(7) Provide a sampling point for compliance monitoring after dechlorination;(8) Provide an alarm system to actuate upon failure of the dechlorination feed system;(9) Have chemical storage tanks equipped with a mechanical mixing device to keep the chemical solution completely mixed, and(10) Have dechlorination solutions, storage tanks, pumps and feed lines protected from freezing.N.H. Code Admin. R. Env-Wq 715.04
(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.