Comparison of drip and spray irrigation vertical greening for on-site disposal of blackwater

When combining irrigation methods with vertical greening, it can be anticipated that the total weight will be far lower than that of traditional hydroponics. In this study, we compared drip and spray irrigation vertical greening systems (DIVGS and SIVGS, respectively) for the on-site disposal of blackwater. The effects of different plant species, fill materials and hydraulic loads on pollutant elimination and microbial community structure were investigated. Statistics and machine learning analysis were employed to optimize the operating conditions and rank the significance of various factors. Both systems were substantially influenced by the plant species and filling materials. The maximum COD, NH₄⁺–N, TN and TP removal efficiencies by DIVGS were 55.29, 47.93, 30.19 and 47.07%, and by SIVGS were 46.71, 43.97, 30.61 and 35.75%, respectively. The DIVGS showed excellent phosphorus removal capacity and the SIVGS displayed a high hydraulic load. Irrigation VGS performed well in terms of low building load, efficient nutrient and wastewater reuse, and ecological sustainability.