Precipitation, tidal and river level impacts on influent volumes of combined wastewater collection systems: A regional analysis

Abstract

Wastewater treatment plants (WWTPs) that treat both foul and storm wastewater will experience significant pressure due to changing precipitation patterns and other geophysical parameters. Limited work has been done to understand the links between factors such as tidal and river levels, precipitation, and influent volumes to WWTPs. This paper analyses the variations of precipitation and their link with influent volumes. The study adopts a new approach to understand influent volume variations by taking into consideration, the combined and individual impacts of tidal and river levels in addition to precipitation; a topic that has not been examined in literature to date. It was found that, on a daily basis, precipitation, tidal elevation, and river levels were each statistically significant in explaining variations in daily influent volumes. On a monthly scale, the combined effects of average daily precipitation and the number of zero rainfall days contributed to the changes in influent volumes. Lastly, this paper proposed monthly pooled spatio-temporal analysis to understand the variable nature of monthly averaged daily influent volumes. These findings will help stakeholders in wastewater management with long-term planning and investment including responses to changing precipitation patterns and their impact on wastewater infrastructure.

Keywords

• Wastewater treatment plants
• Influent volumes
• Precipitation
• Tidal and river level
• Pooled model