Review Development of integrated culture systems and harvesting methods for improved algal biomass productivity and wastewater resource recovery – A review Zhihui Xu a,1 , Haixia Wang b,1 , Pengfei Cheng b,c, ⁎, Ting Chang b , Paul Chen c , Chengxu Zhou b , Roger Ruan c a School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China b College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315211, China c Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota-Twin Cities, Saint Paul, MN 55108, USA HIGHLIGHTS • Microalgae-based wastewater treat- ment reduces the production cost. • Biofilm-based algal culture promotes growth and offers easy harvest. • Bio-flocculation is an economical and ef- ficient harvest method. • Integrated culture and low-cost harvest in wastewater utilization merit further study. GRAPHICAL ABSTRACT abstract article info Article history: Received 13 May 2020 Received in revised form 15 July 2020 Accepted 15 July 2020 Available online 21 July 2020 Editor: Yifeng Zhang Keywords: Culture system Harvesting method Biofilm attached culture Bio-flocculation Wastewater Microalgae biomass has been considered as a potential feedstock for the production of renewable chemicals and biofuels. Microalgae culture combined with wastewater treatment is a promising approach to improve the sus- tainability of the business model. However, algae culture and harvest account for the majority of the high costs, hindering the development of the microalgae-based wastewater utilization. Cost-effective culture systems and harvesting methods for enhancing biomass yield and reducing the cost of resource recovery have become ex- tremely urgent and important. In this review, different commonly used culture systems for microalgae are discussed; the current harvesting methods with different culture systems have also been evaluated. Also, the in- herent characteristics of inefficiency in algae wastewater treatment are elaborated. Current literature collectively supports that a biofilm type device is a system designed for higher biomass productivity, and offers ease of har- vesting, in small-scale algae cultivation. Additionally, bio-flocculation, which uses one kind of flocculated microalgae to concentrate on another kind of non-flocculated microalgae is a low-cost and energy-saving alter- native harvesting method. These findings provide insight into a comprehensive understanding of integrated cul- ture systems and harvesting methods for microalgae-based wastewater treatment. © 2020 Elsevier B.V. All rights reserved. Science of the Total Environment 746 (2020) 141039 ⁎ Corresponding author at: College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315211, China. E-mail address: chengpengfei@nbu.edu.cn (P. Cheng). 1 These authors contributed equally to this work https://doi.org/10.1016/j.scitotenv.2020.141039 0048-9697/© 2020 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv