Performance of a novel photobioreactor for nutrient removal from piggery biogas slurry: Operation parameters, microbial diversity and nutrient recovery potential.

Photobioreactor is deemed to be one of limiting factors for the commercial application of wastewater treatment based on microalgae cultivation. In this study, a novel Flat-Plate Continuous Open Photobioreactor (FPCO-PBR) was developed to treat piggery biogas slurry. The operation parameters, microbial stability and nutrient recovery potential of FPCO-PBR were investigated. Results showed that the appropriate influent mode for FPCO-PBR was multi-point or spraying mode. The optimal hydraulic retention time and interval time for biomass harvesting of FPCO-PBR were both 2 d. Nitrogen and phosphorus recovery rate were 30 mg L-1 d-1 and 7 mg L-1 d-1 respectively under optimal operating parameters. Microbial diversity remained relatively stable in FPCO-PBR. Biomass production rate of FPCO-PBR was 0.47 g L-1 d-1 under optimal operating parameters. The revenue generated from biomass was estimated to be 15.06 $ kg-1, which means that treating one ton of wastewater can generate $ 7.08 in revenue.