Customers are still paying for the plant in their water bills. If we are to use CAP water, the least costly treatment alternative probably would be to upgrade that facility using the existing ozone-chloramine system plus proper corrosion treatment. Voters probably would have to approve additional bonds for any new facility. Water treatment operating costs include the cost of chemicals, energy, salaries, and repair and maintenance. Chloramines and chlorine use almost no energy, and the cost of the chemicals is low.
Ozone is energy intensive, since the ozone is produced on site.
Membrane filtration is even more energy intensive since the process uses energy to force water through the membrane. The smaller the pore size, the more energy is required to operate the system. Membranes also must be cleaned out periodically since the pores become clogged, although some systems have a self-cleaning technique, which itself uses energy. Membranes must be replaced as they lose their effectiveness.