Power plants require a significant amount of water for cooling. However, without preventative treatment, biofouling can occur in cooling water systems, causing loss of efficiency and increased operating costs.  Mollusks, algae, slime and weed not only constrict the flow of cooling water to the heat exchanger surfaces, but also accelerate localized corrosion by restricting oxygen diffusion.  They can also cause destructive turbulence at inlets, which can severely shorten the life of affected equipment.  Continuous chlorination with sodium hypochlorite can prevent biofouling.