Drinking water plants are intended to purify water and make it fit for human consumption and use. Water purification is required each time water must get physical/chemical and organoleptic properties to be safely used.
Depending on the source of supply, water is more or less close to the features of drinking, hygiene, quality. The drinking water plant is intended to remove the natural or anthropogenic elements that contaminate water or that are present in excess: pollutants, minerals, bacteria, virus.
Types of drinking water plants
Depending on degree of contamination, pollution and changes to values, water requires different treatments. Therefore a drinking water plant diagram can be more or less comprehensive and can be made of different stages.
- Physical treatments
- Chemical treatments
Legislative decree No. 152/2006, concerning rules in the environmental field, divides water into 3 categories which require different treatments:
- A1: water requiring physical and disinfection treatments
- A2: water requiring physical, chemical and disinfection treatments
- A3: water requiring deeper treatments, including refinement
Drinking water plant diagram
The above diagram shows a medium-sized drinking water plant.
Untreated water goes in upstream of the plant . The first step is to introduce substances able to “intercept” unsedimentable solids, which stick then together forming flakes thanks to flocculation process (with combining agents and shaking).
The following stage is Sedimentation: Chiariflus® lamella packs by Allegri Ecologia apply right here. Water flows through packs’ modular structures into the clarification process: sludge settles and clarified water goes to further treatment steps.
Next step is filtration, that is to retain unsettled solids.
Clarified water can now be chlorinated, stored and conveyed to the delivery system through pumps.
Allegri Ecologia technology for Madrid water treatment plant
A meaningful example of drinking water plant is Majadahonda in Madrid. Set up in 1967 and changed over time, it serves one million inhabitants and treats 4 cube meters/second of water.
Madrid drinking water treatment plant uses Chiariflus® lamella packs by Allegri Ecologia in the sedimentation phase.
The plant overall integrates the following process:
- Pre-ozonation and pre-chlorination: water disinfection with sodium hypochlorite (chlorine) and organic matter oxidation.
- Physico-chemical treatment: chemical agents and agitators form sedimentable material flakes in the flocculation chamber.
- Sedimentation with lamella packs: the aggregated material settles passing through lamellas and goes to the sludge facility; clarified water remains on the surface and is delivered to the following treatments.
- Grit separators: water is filtered to hold the smallest particle still present after the decantation phase.
- Intermediate ozonation of the residual organic and inorganic matter.
- Activated carbon filters: a new filtration for the total purification of treated water.
- Sludge facility, for their treatment and disposal.