The biological performance of a novel microalgal-bacterial membrane photobioreactor: Effects of HRT and N/P ratio. (December 2020)

• Record Type: Journal Article
• Authors: Zhang, Meijia; Leung, Kam-Tin; Lin, Hongjun; Liao, Baoqiang
• Is Part Of: Chemosphere. Volume 261(2020)
• Publication Date: 2020-12
• Subjects: Microalgal-bacterial membrane photobioreactor -- HRT -- N/P ratio -- Nutrients removal -- Wastewater treatment; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.128199
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: A microalgal-bacterial membrane photobioreactor (MB-MPBR) was developed for simultaneous COD and nutrients (N and P) removals from synthetic municipal wastewater in a single stage for a long-term operation over 350 days. The effects of hydraulic retention time (HRT) and N/P ratio on the biological performance were systematically evaluated for the first time. The results showed that a lower N/P ratio (3.9:1) and shorter HRT (2 d) promoted more biomass production, as compared to a high HRT (3 d) and a high N/P ratio (9.7:1). The highest biomass concentration (2.55 ± 0.14 g L −1 ) and productivity (127.5 mg L −1 ·d −1 ) were achieved at N/P ratio of 3.9:1 and HRT of 2 d due to the highest nitrogen and phosphorus loadings under such conditions. A COD and ammonia-N removal efficiency of over 96% and 99%, respectively, were achieved regardless of HRTs and N/P ratios. In the absence of nitrogen or phosphorus deficiency, shorter HRT (2 d) yielded a higher nitrogen and phosphorus uptake but lower removal efficiency. In addition, the imbalance N/P ratio (9.7:1) would decrease nitrogen or phosphorus removal. Overall, the results suggested that it was feasible to simultaneously achieve complete or high removal of COD, nitrogen, and phosphorous in MB-MPBR under the appropriate conditions. This study demonstrated for the first time that MB-MPBR is a promising technology that could achieve a high-quality effluent meeting the discharge standards of COD and nutrients in one single step. Graphical abstract: Image 1 Highlights: Effects of HRT and N/P ratio on MB-MPBR performance was first investigated. MB-MPBR achieved simultaneous COD and N and P removals and met discharge standards. HRT and N/P ratio affected MB-MPBR performance by controlling nutrients loading rate. Appropriate HRT and N/P ratio is critical to improve MB-MPBR performance. MB-MPBR is a promising technology that can obtain satisfied effluent in one single step.