Failure of sewage pumps: statistical modelling and impact assessment

摘要

Sewage pumping stations are directly responsible for affecting performance, i.e. failing pumps may result in combined sewer overflows or flooding. However, failures of sewage pumps are not yet incorporated in sewer assessments due to lack of knowledge and data. This paper presents the analysis of pump failure data provided by two sewer management authorities in The Netherlands. Pump failures have been studied accounting for the nature of the failures, the operation and maintenance procedures of the management authority, the ageing of the pumps and the changes in the environment of pumps. The analysis shows that sewage pumps fail relatively often due to the composition of sewage and the discontinuous operation of the pumps. The interarrival time and the duration of failures are highly variable and independent of the pump type and the specific function of the pump. The results also indicate that the serviceability of sewer systems is significantly affected by failing pumps. As a consequence, part of the environmental damage due to CSOs (combined sewer overflows) can be avoided by improving maintenance of pumping stations.