Fig. 2: Predicting changes in the synergy between pairwise pollutant removals with observation duration.
From: Sustainability of global small-scale constructed wetlands for multiple pollutant control
a, g Synergy between TNRE and TPRE. b, h Synergy between TNRE and CODRE. c, i Synergy between TNRE and NH4+-NRE. d, j Synergy between TPRE and CODRE. e, k Synergy between TPRE and NH4+-NRE. f, l Synergy between CODRE and NH4+-NRE. Slope_PRE >0 and p < 0.05 indicate a significant synergistic relationship between pairwise pollutant removals (red marks), and Slope_PRE <0 reflects an antagonistic relationship. Slope_OLS >0 indicates an increasing trend of slope_PRE with enhanced duration, and slope_OLS <0 denotes a decreasing trend. TNRE, TPRE, CODRE, and NH4+-NRE reflect the removal efficiency of total nitrogen, total phosphorus, chemical oxygen demand, and ammonium nitrogen, respectively. ***p < 0.01.
