The Impact of Lateral House Connections on the Serviceability of Sewer Systems

It remains unknown how lateral house connections affect the performance of the sewer system, since the assessment of serviceability is mainly based on the state of the main sewer system. Further insight into the contribution of lateral house connections to the overall level of service provided can aid to target investments to parts of the system where it is most effective. To this end, techniques from the reliability theory were applied to a commercial sewer maintenance database to quantify the impact of lateral house connections on the serviceability of sewer systems. Analysis of the data showed that the failures follow a Poisson distribution. A comparison of the derived failure rate with values obtained from a different study revealed that the blockage rate of lateral house connections is an order of magnitude greater than the failure rate of the dominant mechanism of main sewer systems, thereby making the impact of lateral house connections on the serviceability of sewer systems substantial.

[1]  B. Chocat,et al.  Urban flood risk assessment using sewer flooding databases. , 2011, Water science and technology : a journal of the International Association on Water Pollution Research.

[2]  P. O'Connor,et al.  Practical Reliability Engineering , 1981 .

[3]  Neil McIntyre,et al.  A database and model to support proactive management of sediment-related sewer blockages. , 2012, Water research.

[4]  Peter A. W. Lewis,et al.  Testing for a monotone trend in a modulated renewal process , 1973 .

[5]  Norbert Henze,et al.  Recent and classical goodness-of-fit tests for the Poisson distribution , 2000 .

[6]  Harold E. Ascher.  Repairable Systems Reliability , 2008 .

[7]  Jan M. van Noortwijk,et al.  Statistical Modeling of the Serviceability of Sewage Pumps , 2006 .

[8]  Jerald F. Lawless,et al.  A point-process model incorporating renewals and time trends, with application to repairable systems , 1996 .

[9]  Thorkild Hvitved-Jacobsen,et al.  Solids in Sewers: Characteristics, Effects and Control of Sewer Solids and Associated Pollutants , 2015 .

[10]  Amlan Mukherjee,et al.  Modeling Blockage Failures in Sewer Systems to Support Maintenance Decision Making , 2010 .

[11]  Lee J. Bain,et al.  Tests for an Increasing Trend in the Intensity of a Poisson Process: A Power Study , 1985 .

[12]  Mark Scanlon,et al.  Performance indicators for human factors , 2011 .

[13]  B. Klar.  Goodness-of-fit tests for discrete models based on the integrated distribution function , 1999 .

[14]  J A E ten Veldhuis,et al.  The efficiency of asset management strategies to reduce urban flood risk. , 2011, Water science and technology : a journal of the International Association on Water Pollution Research.

[15]  Richard Ashley,et al.  Performance indicators for wastewater services - towards a manual of best practice , 2003 .

[16]  S Arthur,et al.  The holistic prioritisation of proactive sewer maintenance. , 2009, Water science and technology : a journal of the International Association on Water Pollution Research.