Partial Nitrification Algal-Bacterial Granule System Cultivation: Performance, Lipid Production and Biological Community

Zhang, Shaoxiong; Huo, Huanchen; Meng, Fansheng

Partial Nitrification Algal-Bacterial Granule System Cultivation: Performance, Lipid Production and Biological Community

2020

Zhang, Shaoxiong | Huo, Huanchen | Meng, Fansheng

In this study, partial nitrification algal-bacterial granular sludge system was cultivated when treating ammonium-rich wastewater. With 200 mg/L influent NH₄-N concentration, the effluent NH₄-N, NO₂-N and NO₃-N concentrations were maintained at 62.3 mg/L, 67.1 mg/L, and 7.8 mg/L, making it as an ideal influent for anaerobic ammonia oxidation (Anammox). The combined stress of algae growth and free nitrous acid (FNA) should be responsible for partial nitrification in algal-bacterial granular sludge system. The concentration of N-acyl-homoserine lactones (AHLs, quorum sensing molecule) in the effluent of RL was up to 772.5 ng/L, much higher than that (592.8 ng/L) in the effluent of control without light irradiation (RC), leading to enhanced EPS production and granulation in the partial nitrification algal-bacterial granular sludge system. Because of the growth of algae (Chlorella, Scenedesmus, and Navicula), the lipid content in the algal-bacterial granules was 57.4 mg/g-SS, which was about 1.7 times higher than that in the granules from RC, making the algal-bacterial granule a value-added biomass. The relative abundance of Nitrosomonadaceae (AOB) slightly decreased from 5.4% in RC to 3.8% in RL, while Nitrospiraceae (NOB) was completely inhibited in algal-bacterial granules.

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