Studium možností odstraňování vodárenských kalů z potrubí

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 dissertation aims to evaluate the currently used methods to remove water pipe sediment from the pipes within the real drinking water distribution system. The tested methods for sediments removal from pipes were: unidirectional flushing method, Ice Pigging® method and Comprex® method. The evaluation compares the implementation requirements of each method as well as the quality and the quantity of the removed products and is based on large number of operational tests. The dissertation also compares the methods to each other based on the total amount of sediment removed expressed as Total Suspended Solids (TSS) and flushing water consumption. Furthermore, the composition of the removed material and water containing sediments and incrustations is also discussed in terms of further disposal. The amount of total removed TSS varies according to the used method and is influenced by the chosen form of evaluation. The most of the contamination was removed by the following methods in this order: Comprex® (50%), Ice Pigging® (45%) and unidirectional flushing (5%). 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 absolute amounts of TSS achieved ranged from 0.12-4.94 g.m-2 for unidirectional flushing method for plastic pipes, from 1.58-6.46 g.m-2 for the unidirectional flushing method for metal pipes, from 4.36-47.53 g.m-2 for the Ice Pigging® method and from 5,19-69,23 g.m-2 for the Comprex® method. 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 was further been found that in the tested drinking water distribution system it is suitable to use the Comprex® method for cleaning pipes with insufficient hydraulic conditions (such as with a high level of incrustation) and the Ice Pigging® method for preventive maintenance of long straight pipe sections of DN 100-250 mm made of PVC, PE or metallic pipes without advanced incrustation.