Effects of Photoperiods on the Performance of an Algal Biofilm Reactor for Wastewater Remediation & Biomass Production

Algae-based treatment processes have been investigated for use in municipal, dairy, petroleum, oil and gas extraction, and other types of wastewater. The goal of such treatment is to provide a cost-effective method to remove nutrients (such as NO-2-N, NO-3-N, NH+4-N, PO34--P), biochemical oxygen demand, suspended solids, and trace metals, and also to produce biomass for downstream processing into value products. Conventional algal treatment systems typically involve using a raceway or other suspended- growth method to generate biomass. These systems have many limitations including the cost to separate algae from wastewater, large space required to operate, and growth limiting factors created by limited sunlight due to turbidity and water depth, and also the low solubility of CO2 in water as the carbon source for algae and cyanobacteria. The Rotating Algal Biofilm Reactor (RABR) directly addresses these limitations by operating as a semi-submerged bioreactor with a substrate on which an algal biofilm culture develops. This reactor exposes the biofilm to both light and atmospheric CO2 above the wastewater as well as the nutrients in the wastewater as it rotates in and out of a wastewater. This helps to maximize efficiency and minimize the surface footprint of reactor systems. In order to further increase is necessary to test the effects of different photoperiods on rotating algal biofilm reactors to investigate their yield and growth rates, and the resulting effects of wastewater remediation. This experiment focuses on evaluating the performance of RABRs under different photoperiods