Comparison of Modern Drinking Water Network Maintenance Methods: Evaluation of Removed Deposits in the Form of Total Suspended Solids (TSS)

Abstract

Water pipe sediment removal should be implemented as an integral part of water mains maintenance in order to steadily supply consumers with drinking water of high quality. Considering the number of different water pipe sediment removal methods, the article aims to evaluate the currently used methods to remove water pipe sediment from the pipes of the drinking water distribution system. The evaluation compares the implementation requirements of each method as well as the quality and the quantity of the removed products. The tested methods were unidirectional flushing, Comprex®, and Ice Pigging®. The results of the comparison are expressed in terms of total suspended solids (TSS) recovery, metals mass concentration and water consumption. Since contamination can settle along the entire surface of the pipeline, it is most appropriate to recalculate the results per unit area of the pipeline. The results point at the following efficiency the Comprex® method was the most efficient in removing TSS, Ice Pigging® was the next and unidirectional flushing removed a negligible amount of TSS compared to the other two methods. The absolute recovery of TSS was 0.12–3.01 g·m−2 in unidirectional flushing of plastic pipes, 1.58–8.54 g·m−2 in unidirectional flushing of metal pipes, 4.36–47.53 g·m−2 in Ice Pigging®, and 5.19–69.23 g·m−2 in Comprex®. The composition of the sediment was strongly influenced by particle origin: Pipe material affected the crystalline phase of the sediment and the water source and the age of the pipe affected the amorphous phase of the sediment. Therefore, it was found that evaluation of efficiency based on the amount of TSS removed is only suitable for sites that meet the same conditions as pipe material, water source and ideally the pipe age. It has further been found that the Comprex® method can be advantageously used in real conditions to clean pipes with insufficient hydraulic conditions (such as with a high level of incrustation), as the cleaning has low water flow velocity requirements.

Climate change and management of biofilms within drinking water distribution systems

“…Further studies are needed due to the increasing use of other emergent methods that may have a different effect on the biofilm mobilization. For example, Pourcel and Duchesne (2020) observed differences in the mobilization of material from the DWDS pipes between the application of flushing and air scouring, and Jurek Vidlářová and Heviánková (2021) demonstrated differences in the efficiency on removing material from drinking water pipes when they compared different maintenance methods, including unidirectional flushing, air scouring, and ice pigging.…”

Effect of swabbing cleaning method on biofilm communities of a drinking water distribution system in Madrid (Spain)

“…However, flushing can be difficult to apply in pipes with large diameters such as trunks mains because it is impossible to reach the necessary water velocity [16]. In addition, for a flushing event a very large volume of drinking water is wasted [17], and this is promoting that the rest of the techniques are emerging as an alternative cleaning method.…”