Section Env-Wq 716.11 - Sludge Pumps and Piping(a) Sludge pumping systems shall be designed with adequate capacity to cover the full range of anticipated solids concentrations and sludge production rates. Operating pressures and head losses shall be calculated to account for the higher friction factors associated with the type of sludge being pumped.(b) Duplicate sludge feed pumps shall be provided.(c) Net positive suction head conditions appropriate to pumping equipment flow and sludge characteristic variations shall be provided.(d) Sampling valves shall be installed at the sludge pumps.(e) Sludge withdrawal piping shall have a minimum diameter of 6 inches. Sludge pump discharge piping shall be at least 4 inches in diameter. Where withdrawal is by gravity, the available head on the discharge pipe shall be at least 4 feet greater than the calculated head loss. All sludge piping systems shall be designed to provide a velocity of at least 2 feet per second.(f) Provision shall be made for draining and flushing discharge lines.(g) Gravity piping shall be laid on uniform grade and alignment. Slope on gravity discharge piping shall be not less than 3 percent.(h) Provision shall be made for draining and flushing sludge processing lines.(i) Piping installed inside digestion tanks shall have the corrosion resistance and support stability appropriate for a highly corrosive environment.(j) For sludge pumping systems, alarms shall be provided for: (2) Loss of pressure; and(k) Sludge pumps shall be equipped with high pressure shutoff switches.N.H. Admin. Code § Env-Wq 716.11
Adopted byVolume XXXIV Number 46, Filed November 13, 2014, Proposed by #10693, Effective 10/15/2014, Expires10/15/2024.