In the field of wastewater treatment, the need for efficient and sustainable solutions is perpetual. This study delves into the efficacy of attached growth systems, a burgeoning approach that capitalizes on microbial communities immobilized on various substrates, in addressing diverse wastewater treatment challenges. Biofilm reactors natural tendency to form structured communities on solid surfaces. By investigating the geometry of biocarriers in these systems, this study evaluates the factors influencing treatment efficiency. We employed experimental trials, focusing on media length and surface area, utilizing high-density polyethylene (HDPE) tubing sections of varying dimensions. Results indicate that perforated biocarriers outperform hollow biocarriers, showcasing superior organic matter removal efficiencies, attributed to their larger surface area and enhanced mass transfer capabilities. Additionally, biofilm growth was found to correlate directly with surface area, as greater attachment sites foster denser and more resilient biofilms. The concentration of microbial activity towards the edges of the media suggests their pivotal role in nutrient removal. Overall, this study underscores the significance of biocarrier geometry in enhancing treatment performance and advancing the sustainability of attached growth-based wastewater treatment processes.