The transport of wastewater presents operators with increasing challenges for their wastewater pumps due to an increasing proportion of tear-resistant fibrous materials and new types of hygiene articles in the wastewater. Clogging of wastewater pumps results in increased personnel requirements and repair costs.Up to now, wastewater pumps have been classified according to ISO DIN EN 9906 in terms of their efficiency. However, the functionality or operational availability is of increasing importance, as both maintenance and fault clearance are costly and reduce operational reliability.The test method used to obtain the results described in this paper works with artificial wastewater, which is conveyed through the pump by means of tear-resistant wet wipes in various load classes according to defined sequences in the test bench. The most common wastewater impellers are examined: the vortex impeller, the 1-channel impeller and the multi-channel impeller.This paper describes the different clogging behaviour of the impellers of different performance classes just mentioned, which were recorded during the tests on the test bench. In addition to the findings of the points susceptible to clogging, the maximum uptake of solids by an impeller is also discussed. The maximum uptake of solids is defined as the degree of saturation. Furthermore, it is shown to what extent the different clogging behaviour influence the hydraulic performance and the resulting efficiency changes.In these tests, it became apparent that wastewater impellers react differently to clogging. On the one hand, it can lead to a reduction in hydraulic function, which reduces the efficiency of the system. A distinction must be made here as to whether the impellers with a certain amount of solids, a defined degree of saturation, retain their function or are brought to a standstill. On the other hand, the hydraulic performance can remain almost constant or, in some cases, be increased in spite of the clogging that occurs, but this is accompanied by an increased power requirement and can thus reduce the service life and the efficiency of the system.Clogging can thus affect the hydraulic performance of an impeller in a variety of ways, which will be highlighted in this paper. The different clogging behaviour of different impellers and the resulting changes in operating parameters will be discussed for several wastewater pumps.

Different Clogging Behavior of Wastewater Pumps

Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2021/volume/85284

ASME 2021 Fluids Engineering Division Summer Meeting (FEDSM2021)

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