SANITARY SEWAGE SYSTEM RECOVERY ASSESSMENT

File: 011696_129_15_022.txt
Page: 022
Total Pages: 71






                            the pump stationi3

                            Excessive pumping,

                            Sand and debris deposition within the system
                            vented manhole covers allbwin'g sand 'to enter and
                            odors to escape


                      Our  investigation of  the system indicated that some of
                 the Ripelines are severely corroded.       In some cases, the
                 concrete and piping within pump stations are corroded. This
                 corrosion was caused by hydrogen sulfide and existed prior to
                 the invasion. We also verified by inspection of -the influent
                 structures of the wastewater treatment plants that sand and
                 grit has been a continuing problem and existed prior to the
                 war. The details of the condition of the system prior to the
                 -invasion are well documented in the above referenced Black
                 Veatch report. We would describe the collection system as a
                 "house of cards", or a "paper machell system because of -its
                 corroded AC piping which.is approximately 90% of the' system.
                 An example df a major design oversight is at the Ardiya-STP
                 influent headworks, where failure to provide appropriate
                 thrust blocks on a 45 degree elbow on each of three large
                 diameter pressure sewer lines has caused chronic fracture and
                 leakage problems. (The previous conclusion is the opinion of
                 LT. Hatherly)       There were major rehabilitation and
                 refurbishment efforts under way in the Ardiya STP catchment
                 area prior to the invasion. significant by-passing of raw
                 sewage was also occurring.


                      3. Condition at Time of Liberation.        The events which
ing
                 problems and caused additional problems. The extremely Sp-ptic-
                 conditions within the system aggravated the hydro4en sulfide
                 Problems and thos lead to an increased rate of corrosion and
                 odor problems._ The low or no flow conditions results in
                 blockage of the gravity sewer lines. Loss of electrical power
                 during the allied forces liberation, and lack of preventative
                 maintenance led to failures of the pump stations and flooding
                 of some pump stations.      Flooding ruined pump motors and
                 controls in the dry@pit pump stations. Wet-pit pump stations
                 with submersible type motors (in the minor pump stations) are
                 less susceptible to flood damage. Lack of maintenance caused
                 bearing failure in some pump stations. The screw pumps are
                 es ecially susceptible to this type of failure.        Lack of
                 maintenance and excess grit and debris may have caused valve
                 failure. Gate valves may not close properly and check valves
                 may malfunction.    We did not see any intentional acts of
                 sabotage to the collection system.       Although we did not

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Box ID = BX000000
Unit = CONST ENG LABS  
Parent Organization = CORPS OF ENGS   
Folder Title = SANITARY SEWAGE SYSTEM RECOVERY ASSESSMENT                                                      
Subject = SANITARY SEWAGE SYSTEM RECOVERY ASSESSMENT
Document Number =        129
Image file name = 00000023.tif