Ice pigging comes down to flushing the network with a mixture of ice crystals and water, “wiping” material from the inner surfaces of pipelines.
Reliable information about the effectiveness of the method was provided by visual inspection inside the pipelines prior to and after the execution of ice pigging, using a specialized camera. The camera inspections show that deposits on the inner surface of the pipeline were removed completely.
Although the project proceeded slower than expected, the results of the cleaning were good. Ice pigging proved to be a good and hygienic technique to clean pipes, removing deposits and biofilm from the pipe wall surface, especially in situations where conventional flushing does not provide a solution. Visual inspections show that after ice pigging the pipes were thoroughly clean. A final evaluation of the project has yet to be made.
Up-scaling from a pilot demo to a full scale project appeared to be more complicated than expected. Technical problems with the ice production facility and the poor technical condition of valves in the network caused more delays than calculated prior to carrying out the work.
Approximately 100 km of Oasen’s PVC water mains with a diameter between 63 and 200 mm was thoroughly cleaned this way.