c. Close the bleach metering valve.
d. Close the backwash water supply valve.
e. Close external sewage inlet and discharge valves (TM 55-1905-223-24-18).
f. Remove the end sediment tank cover assembly (paragraph 2-12).
g. Remove the hose clamps and disconnect the flexible coupling in the vent piping on the cover assembly
at point (3) in FIGURE 2-8.
Toxic and flammable vapors are generated in the sewage system. Provide
ventilation from outside source before removing treatment tank covers. Avoid
open flames and prolonged breathing of fumes.
h. The cover assembly consists of a plate joined by a common section of PVC vent piping. Remove the
cover carefully so as not to crack or damage the piping.
i. Remove the six capscrews, nuts, and washers (2, FIGURE 2-8).
j. Remove the cover assembly (4).
k. Remove the cover gasket (1). Discard the gasket.
The PVC piping and joints must be water tight.
a. Check the PVC vent piping for signs of cracks or breaks. If the piping is cracked or broke at any
point, the cover assembly must be replaced. Refer to Removal and Replacement steps in this
b. Replace the mid sediment tank cover gasket (1, FIGURE 2-8).
Refer to the Removal and
Replacement steps in this procedure.
a. Clean the gasket sealing surfaces on the sediment tank and cover assembly (4, FIGURE 2-8).