<prompt> Purification of water at large scale is done by all exceptDisinfection of wellRapid sand filterSlow sand filterStorage  <response>: Purification of water on a large scale Storage Filtration by slow sand or biological filters rapid sand or mechanical filters 3. Disinfection Purification of water on a small scale Household purification of water Disinfection of wells refer pg:771 park 25th edition 