Scalable photobioreactor monitoring: A validated approach to biofouling detection via light transmission method

Abstract

The presence of biofouling in transparent photobioreactors represents a significant challenge to microalgal cultivation, affecting light penetration, photosynthetic efficiency, and overall biomass productivity. This study proposes a novel non-invasive method for biofouling detection, founded on the principle of light transmission analysis. This method has been validated across a range of systems, from laboratory to pilot-scale, demonstrating detection sensitivity capable of measuring light reduction from the maturation of the biofilm until it forms an impermeable, continuous layer. The method demonstrated consistent performance across different transparent materials (PMMA and glass) and geometric configurations, with biofilm detection thresholds as low as 1 % light reduction in pilot-scale tubular photobioreactor and 99 % reduction in lab-scale tubular system. Quantitative analysis revealed that biofilm formation typically reduced light transmission by 85 % before natural detachment occurred. The method's scalability was confirmed through successful implementation on systems ranging from 150 mL laboratory tubes to 120 L pilot reactors, offering a cost-effective solution for real-time biofouling monitoring without system modification or maintenance requirements.

The results show that this approach detects biofilm formation and removal while maintaining its simplicity and non-invasive nature. Given the current limitations of industrial photobioreactor applications, particularly the need to reduce operating and maintenance costs, this method offers a valuable solution for real-time biofouling monitoring. It allows early detection of biofilm in critical areas and helps reduce biofouling. This study highlights the potential of light transmission method as an effective and practical tool for enhancing photobioreactor performance in various applications.