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Chapter 19

Hard Water water that will not easily latther with soap, caused by the presence of Ca & Mg ions
Treatment - Screening passing the water through a wire mesh to remove floating debris
Treatment - Flocculation Aluminium sulfate is added and suspended solid to stick together to form larger particles
Treatment - Settlement water flows from the bottom of large tanks and very slowly rises to the top; as a result the 90% of the particles are removed.
Treatment - Filtration The water is passed through large beds of sand, this removes remaining solids. the water is now clear
Treatment - Chlorination Chlorine is added to water to sterilise it.
Treatment - Flourination Sodium flouride is added to prevent tooth decay
Treatment - pH adjustment Calcium Hydroxide/ Sulfuric acid are added if needed to maintain a pH of 7-9
Biochemical Oxygen Demand The amount of dissolved oxeygen consumed by a biological action when a sample of water is kept at 20' in the dark for 5 days
Eutrophication The enrichment of water with nutrients, which leads to excessive algae growth
Created by: MarkA0845