| Abstrakt: |
The performance of the microalgae-based wastewater treatment (MBWT) process was investigated with a main focus on two key operational parameters: operation modes and hydraulic retention time (HRT). Compared with continuous mode, consistent semi-continuous cultivation exhibited comparatively sustainable algal growth due to the well acclimatization effect. When operated semi-continuously with an HRT of 5 d, a Chlorella-based MBWT system obtained the highest average algal growth rate at 0.054 d–1, with subsequent biomass accumulation at 0.21 g L–1. Average total nitrogen, NH4 +–N and chemical oxygen demand removal was 64.00% ± 6.48%, 73.52% ± 3.96% and 44.66% ± 13.29%, respectively, while total phosphorus removal remained stable at >99% despite different operational parameters applied. Co-influence of cyclical light of a natural light/dark cycle on semi-continuous MBWT was also observed, and the result indicated a relationship between possible biomass harvesting time and diel patterns of algal cells. Moreover, the techno-economic analysis displayed the nutrients recovery advantage of microalgae, as approximately 5.29 g nitrogen and 10.08 g phosphorus could be recovered per ton treated wastewater, which equals 193.2 t nitrogen and 36.8 t phosphorus for a scaled-up MBWT plant with a capacity of 3.65 × 107 m³. This also creates potential economic benefits of 0.8 M Chinese Yuan (CNY) for the MBWT plant annually. [ABSTRACT FROM AUTHOR] |
