Pathways of Nitrogen and Phosphorus Utilization and Removal from Cyanobacteria Wastewater by Combining Constructed Wetlands with Aerobic Reactors

Liying Gong, Xuanxuan Zhao and Guangcan Zhu
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Liying Gong: School of Energy and Environment, Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210096, China
Xuanxuan Zhao: School of Energy and Environment, Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210096, China
Guangcan Zhu: School of Energy and Environment, Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210096, China

Sustainability, 2022, vol. 14, issue 14, 1-16

Abstract: Due to its low C/N ratio and high concentrations of nitrogen and phosphorus, the effluent of anaerobic cyanobacteria fermentation cannot be directly discharged without further treatment. To effectively reduce nutrient loads and utilize the nutrient resources of biogas slurry generated from the anaerobic digestion of stored algae, two different aerobic treatment units (AUs) were combined with an ecological treatment unit (EU) to create two different treatment systems. The two AUEU systems paired a constructed wetland (CW) with either a cascade biological contact reactor (CBCR) or a carrousel oxidation ditch reactor (CODR). In this paper, the water quality characteristics of biogas slurry were measured, and comprehensive experiments on the two trial-treatment systems were carried out to validate their performance in removing pollutants and utilizing resources. Furthermore, the pollutant removal efficiencies of the combined systems, along with the removal mechanisms and utilization of the nitrogen and phosphorus in the CWs, were also investigated. The results showed that the CWs, with aquatic vegetation, took up the majority of removed nitrogen and phosphorus by absorption, which effectively reduced the concentration of pollutants in the effluent and enabled the nitrogen and phosphorus to be reused in plants. Biomass assimilation by the absorption by vegetation took up 75.8%, 66.1%, 70.3%, and 86% of the removed NH 4 + -N, NO x − -N, TN, and TP, respectively.

Keywords: cyanobacteria; constructed wetlands; aquatic plant; removal and utilization; plant assimilation (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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