Figure 3.

Changes over time in (A,B) pH and (C,D) NH₄⁺-N content in (A,C) artificial domestic sewage water and (B, D) artificial animal farm wastewater in the presence of various plant species and their combinations: No. 10, Eleocharis plantagineiformis; No. 11, Hydrocotyle vulgaris; No. 12, Ipomoea aquatica; No. 13, Salvinia natans; No. 14, S. natans–E. plantagineiformis; No. 15, H. vulgaris–E. plantagineiformis; No. 16, I. aquatica–E. plantagineiformis; No. 17, S. natans–E. plantagineiformis–H. vulgaris. Mean results of three replicate experiments are shown, with standard errors of >5%. For clarity, standard errors of pH results are only shown for maximum and minimum values per time point.