Fig. 5

MCDI system performance under optimal operation condition (2.0 V for 30 min in charging step, 0.0 V for 3.75 min followed by − 2.0 V for 3.75 min in stop-flow regeneration step, and − 2.0 V for 7.5 min in discharging step). Variations in (a) EC, (b) Na+, K+, Ca2+, and Mg2+, (c) NH4+, (d) Cl− and NO3−, and (e) total P measured as phosphate ions