Hydrogen Sulfide In A Collection System: What We Should Know And Do To Prevent Human Injury And Sewer Asset Deterioration.

NASSCO Tech Tips
By NASSCO member Jim Harris, PE, TFE Resources | October 2013, Vol. 68 No. 10

But what of our existing sewers? It is very important that we know the precise condition of the pipe and have a way of tracking the rate of deterioration. Remember, we don’t want to define a condition after a pipe collapse – we want to identify the extent of ongoing pipe damage caused by hydrogen sulfide and prevent the collapse from ever happening. This is one of the many ways where the NASSCO PACP/MACP program analysis is particularly useful. It allows us to observe the pipe deterioration and progressively code and rate it as time passes. Common codes will indicate pipes being in good condition or in the process of deteriorating by using various levels of codes beginning with surface roughness increased (SRI) all the way to surface missing wall (SMW). This coding allows future inspectors to observe changes in the pipe condition and record the change that has occurred. Asset management analysts can then project the rate of deterioration and alert utilities as to the need for rehabilitation or replacement. In many cases the deterioration of pipelines and manholes, the erosion of bedding materials and the resulting pipe collapse can be readily monitored and maintenance procedures implemented to prevent the high costs associated with pipeline collapse.

While hydrogen sulfide gas may cause some to hold their noses, it may cause others to take action. It is much more important that we understand the potential for sickness, injury, death and collection system deterioration. Awareness of the potential hazards, detection, and careful and consistent observation can prevent each of these situations, reduce the consequences to human life and proactively prevent the deterioration of one of our most valued commodities: the sewer.

For more information, please visit NASSCO’s website at www.nassco.org.