Research and application status of ecological floating bed in eutrophic landscape water restoration

Ecological floating bed (EFB) has become the preferred technology due to its reputation of green economy, convenience, and efficiency in treating eutrophic landscape water. Based on the statistical analysis of abundant literatures, this paper systematically summarizes the component elements, design parameters, purification mechanism, purification ability, strengthening methods and the correlations among various parameters of EFB, and points out some issues existing in the current research and applications. The results show that the coverage of 5% ~ 38% and water depth of 60 ~ 110 cm should be recommended for EFB design. The microbial transformation-sedimentation contributes mostly to the removal of pollutant, leading to the contribution rate of 51.9% ± 26.4% to nitrogen (N) removal and 50.8% ± 20.4% to phosphorus (P) removal in water respectively. Meanwhile, the average purification abilities of EFB for carbon (C), N and P in water are 4.59 ± 3.82, 0.43 ± 0.35 and 0.04 ± 0.04 g m-2 d-1 respectively. The purification effect is relatively superior when the initial concentration of C, N and P in water is close to C: N: P = 115: 11: 1. In order to enhance the EFB purification efficiency, the methods of artificial aeration, biological chain extension, functional filler introduction, and composite EFB construction can be used. Furthermore, the purification ability of EFB per unit area is correlated positively with water temperature and initial pollutant concentration (r ≥ 0.577, p < 0.01), and correlated negatively with EFB coverage (r ≤ -0.598, p < 0.01). The future research of EFB should focus on enhancing its purification efficiency and seasonal adaptability, studying the mechanism of algae inhibition by allelochemicals, and exploring the harvesting management and resource utilization of plants. This paper provides more reasonable design parameters, feasible management strategies and prospective research directions for environmental managers and researchers who would like to adopt EFB to purify eutrophic landscape water.