Section Env-Wq 715.03 - Hypochlorite Systems(a) Hypochlorite solution feed equipment shall incorporate effluent flow proportional control systems or effluent flow proportional combined with demand proportional control systems.(b) Hypochlorite feeders shall be of the positive displacement type.(c) Hypochlorite solution storage shall be of sufficient volume to provide for dosing at the anticipated maximum dose rate at design annual average flow for 15 days.(d) Hypochlorite solution feed systems shall be capable of dosing at the anticipated maximum dose rate at maximum flows, with turndown capabilities to accommodate minimum flows.(e) A redundant hypochlorite feed pump shall be provided.(f) Rooms housing hypochlorite feed equipment and appurtenances shall be mechanically ventilated to provide at least 6 air changes per hour.(g) Mechanical ventilation systems shall draw from floor level.(h) Application of hypochlorite shall be as follows:(1) Mixing of the disinfectant at the point of injection before the contact tank shall be provided using hydraulic or mechanical means; and(2) A minimum contact period of 15 minutes at peak hourly flow or maximum rate of pumping shall be provided.(i) Contact tank design shall be as follows:(1) The contact tank shall have a minimum of 2 separate chambers;(2) The contact tank shall be configured to reduce short-circuiting of flows;(3) A minimum 40:1 length to width ratio of the contact passage shall be provided;(4) A scum baffle and scum removal piping shall be provided at the effluent end of the tank;(5) Provisions shall be made for draining and washing down the contact tank; and(6) Drainage flow shall be returned to the treatment process.(j) Facilities shall be provided for obtaining samples, either grab or continuous as stipulated by permit, of the disinfected effluent after contact.(k) Equipment for residual chlorine testing and recording shall be provided, which is capable of measuring in the range from 10 parts per million to the lower limit established by permit.(l) Alarm systems shall be provided for: (1) Low hypochlorite storage tank level;(2) High hypochlorite storage tank level; and(3) Failure of the hypochlorite feed system.(m) Hypochlorite solution, storage tanks, pumps and feed lines shall be protected from freezing.N.H. Code Admin. R. Env-Wq 715.03
(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.