Modelling and pH Control in Raceway and Thin-Layer Photobioreactors for Wastewater Treatment

One of the most critical variables in microalgae-related processes is pH; it directly determines overall performance production system especially when coupling with wastewater treatment. In treatment processes, adequacy pH has a large impact on microalgae/bacteria consortium already developing these systems. For cost-saving reasons, usually controlled by classical On/Off control algorithms during daytime period, typically dynamics and disturbances not being considered design system. This paper presents modelling open photobioreactors, both raceway thin-layer, using advanced controllers. types classic was implemented compared Proportional–Integral (PI) control, also operation only daylight period complete daily time evaluated. Thus, three major studied include (i) type reactors (thin-layers raceways), (ii) algorithm (On/Off PI), (iii) (during throughout nighttime). Results show that adequately although each requires different algorithms, largely improved PI controllers, controllers allowing us to reduce total costs process reduction CO2 injections. Moreover, cycle (including night) increases amount be injected, otherwise reducing it, but improves process. Optimal systems here developed are highly useful develop robust large-scale processes.