Identification of maximum loads that cause blockages in wastewater systems

Personal hygiene products such as toilet paper and flushable wipes are disposed of into sewer systems. In sewers, they blend with other wastes such as grease and sand to form a mixture of waste materials that accumulate over time and cause sewer backups. Wastewater authorities and household residents incur financial costs, property damage, and health risks due to sewer blockages. To minimize such risks, this study assesses the amount of toilet paper that can be transported safely from toilets through household drains. For this analysis, we collected various toilet paper samples and categorized them into two groups as 1-Economical, 2-ply, and thin products versus 2- Premium, 3-ply, and plush products. Then, representative samples from each category were tested according to toilet and drain-line clearance test protocol developed by the International Water Services Flushability Group, an organization representing wastewater authorities from around the world. The results elucidated critical loadings that are classified as sewer-safe, risky, and unsafe. As an example, up to 20 sheets of economical and 2-ply toilet paper was discharged safely with a single flush; hence, this range was defined as sewer-safe. Similarly, 20-40 sheets constituted a risky range for accumulations, while >40 sheets choked the toilet. For comparison, up to 8 sheets of premium and 3-ply toilet paper was transported safely, while 8-15 sheets were risky for accumulations, and >15 sheets caused blockages. In light of the findings, economical type toilet papers are preferable to prevent potential backups in household toilet and drain-line systems. In particular, economical products are highly recommended for entities such as shopping centers, student dormitories, and sports arenas.