Analyzing the Hydraulic Impact of Non-flushable Wet Wipes on Sewer Systems

Various factors, including the accumulation of fats, oils, grease, tree root intrusion, and non-biodegradable items like wet wipes and sanitary products, cause sewer blockages. The COVID-19 pandemic has aggravated the situation, with improper disposal of wipes leading to severe blockages, causing backups, flooding, and overflows. However, the understanding of wipe-caused sewer blockage formation and the resulting hydraulic impacts is lacking. This research aims to address this gap by examining the likelihood of wipes snagging on sewer imperfections and analyzing the resulting backwater effects. Laboratory experiments were conducted to replicate real-world scenarios to explore the hydraulic effects of non-flushable wet wipes on sewer systems. Results showed a significant variation in the likelihood of wipes snagging on sewer imperfections, with probabilities ranging from 93 to 0%, depending on the imperfection’s location within the sewer and the prevailing flow rate. Similarly, the probability of wipe accumulation exhibited a wide range, from 71% to zero, highlighting the critical influence of both flow rate and the specific positioning of the imperfections. The experiments further revealed that blockages significantly increase upstream water levels, with the extent of this rise directly depending on the blockage size and the flow rate. These findings underscore the need for better design and management of urban wastewater systems to enhance their overall resilience and efficiency.