Section Env-Wq 1508.15 - Pretreatment Practices: Flow-Through Devices Flow through devices such as hydrodynamic separators, water quality inlets, and oil/particle separators shall comply with the following:
(a) The devices shall be designed according to the manufacturer's recommendations based on the WQF to remove a minimum of 80% of U.S. Silica grade OK-110 sand at the WQF;(b) Water quality inlets and oil/particle separators shall have a 4 foot minimum sump;(c) Water quality inlets shall be a 3-chamber design, with the first and second chambers having a minimum of 400 cubic feet of storage per acre of contributing impervious area;(d) Each water quality inlet and oil/particle separator chamber shall be accessible by means of a separate manhole;(e) The contributing area to the oil/particle separator shall not exceed 1.0 acre of impervious area;(f) Oil/particle separators shall only be used in an off-line configuration to treat the WQF; and(g) Oil/particle separators shall have a minimum of 400 cubic feet of permanent pool storage per acre of contributing impervious area.N.H. Admin. Code § Env-Wq 1508.15
(See Revision Note #1 at chapter heading for Env-Wq 1500) #9343, eff 1-1-09; (See Revision Note #2 at chapter heading for Env-Wq 1500) amd by #9817-A, eff 12-1-10
Amended by Volume XXXVII Number 32, Filed August 10, 2017, Proposed by #12342, Effective 8/15/2017, Expires 8/15/2027.Amended by Number 41, Filed October 12, 2023, Proposed by #13758, Effective 9/28/2023, Expires 9/28/2033 (formerly Env-Wq 1508.14) (see Revision Note #4 at chapter heading for Env-Wq 1500).