A Review of the Effects and Influencing Factors of Vertical Greening Systems in Wastewater Treatment

• Published in: Sustainability Vol. 17; no. 13; p. 6138
• Main Authors: Zhu, Wencong, Zheng, Xiangyong, Zhao, Min, Xiang, Huijun, Zhang, Suyang, Han, Wenjuan
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.07.2025
• Subjects: Efficiency; Effluents; Environmental aspects; Hydraulics; Methods; Pollutants; Purification; Sewage; Vertical gardening; Wastewater treatment; Water purification; Water quality; Zeolites; China
• ISSN: 2071-1050; 2071-1050
• DOI: 10.3390/su17136138

Vertical greening systems (VGSs) serve as an advanced ecological wastewater treatment technology, offering advantages such as a small spatial footprint and increased green space coverage. VGSs have been widely applied to treat various types of wastewaters, including blackwater and greywater. However, a systematic review of the pollutant removal efficiency of VGSs in treating blackwater and greywater, as well as the influencing factors, remains lacking. This study compiles data on the removal efficiencies of chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and ammonium nitrogen (NH4+-N) from greywater and blackwater using VGSs. Additionally, the effects of the hydraulic loading rate, substrate type, and the number of system layers on pollutant removal performance are assessed. When treating blackwater, the pollutant removal efficiency showed a positive correlation with hydraulic loading within the range of 85 L × (m2 × d)−1 to 200 L × (m2 × d)−1; substrates such as zeolite or vermiculite exhibited superior removal performance, and increasing the number of system layers enhanced the pollutant removal efficiency. When treating greywater, the hydraulic loading rate and system layers have limited influence on COD and TN removal, while excessive hydraulic loading or system layers may negatively affect TP removal. Substrate mixtures composed of perlite and coconut coir achieved a higher pollutant removal efficiency. In conclusion, optimizing key parameters such as the hydraulic loading rate, substrate composition, and the number of system layers can significantly enhance the pollutant removal efficiency of VGSs.