Proper LP Inspection - Texas Onsite Wastewater Association
North Carolina Sea Grant (1982) • Design Method (cont’d) • Selection of hole spacing (arbitrary selection of 3 to 5’) • Selection of discharge pressure head (2 to 4’) • Calculate head for remaining trenches in group by adding elevation between laterals • Charts then used to look up flow rate for holes in a trench • Trench flow rate found by multiplying the hole flow rate by number of holes in trench • Summation of trench flow used to find required pump flow rate (system flow rate)
North Carolina Sea Grant (1982) • Design Method (cont’d) • System flow rate used to find friction loss in piping to field and total dynamic head (TDH) • TDH and system flow rate use to select pump where require point below pump curve • Valve then used to adjust discharge pressure to selected level as measured in stand-pipe connected to highest trench.
hydromulch Berm & swale
Riser to grade with screws Masonry
References • EPA Onsite Wastewate