Cost and environmental impact of nanofiltration in treating chemically pre-treated surface water

Nanofiltration is an effective technique in improving the organic matter removal from coagulated surface water, but the process should also be economically feasible and environmentally sustainable when applied. Cost and environmental impact of nanofiltration installed after conventional surface water treatment were calculated and evaluated at different operating parameters in this study. The installation of nanofiltration after conventional surface water treatment would increase the cost of treated water in a minimum by 0.11 €/m3 in the studied case. The least cost was gained at the higher studied recovery (83%) at the driving pressure of 6 bar, where also the total environmental impact was well balanced. However, the installation of nanofiltration would increase the environmental impact of water treatment remarkably and improvements should be done to minimise these effects. The main ways to minimise the cost of nanofiltration were related to recovery of the process, energy consumption, membrane lifetime and membrane cleaning, whereas the environmental impact minimisation was mostly related to recovery of the process and energy consumption.