Page 46 - Reliability and Maintainability of In service Pipelines
P. 46

Introduction 35


















































           Figure 1.6 Process occurring in sewer under sulfide build up conditions (ASCE No.
           69, 1989).

           that H 2 S is released from the surface of the sewage stream. The average flux of
           H 2 S to the exposed pipe wall is equal to the flux from the stream into the air mul-
           tiplied by the ratio of the surface area of the stream to the area of the exposed
           pipe wall, which is the same as the ratio of the width of the stream surface (b)to

           the perimeter of the exposed wall (P). The average flux of H 2 S to the wall is
           therefore calculated as follows (Pomeroy, 1976):

                                           3=8
                                              ½
                                  Φ 5 0:7ðsuÞ  jDSŠðb=PÞ                 ð1:17Þ
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