In general, approximately 70 to 90 percent of the energy used in surface water treatment is for pumping. Pumps use mechanical forces to move gases, liquids, or slurries from one place to another; this fluid handling accounts for the largest use of energy worldwide; however, the efficiency in pumps decreases after years in service. The main problem is increased turbulence, caused by the detrimental effects of erosion corrosion.

• The different forms of corrosion include uniform corrosion and localised corrosion (i.e. bi-metallic corrosion, deposit corrosion, pitting and selective dissolution).
• The different forms of erosion include impingement erosion, entrainment erosion and cavitation.

These lead to rough and pitted surfaces, which in turn increase friction, therefore reducing the efficiency of the system.