Experiences

Development and implementation of a water-purification

Amparo Ponce Polo

Spain

High Secondary School

Science

Laboratory

Direct

This experience allows students to study the main physical, chemical and biological processes taking place in a water treatment plant.

To experiment we need 3 plastic bottles that we will cut in a half and we keep 5 containers (3 of top of the bottle and 2 of the bottom of the bottle). The assembly is available if we put all the containers in decreasing heights to allow the water to go from one container to another by gravity.
• In the first container (without cap) we put a filter consisting of a metal net to eliminate suspended matter (physical treatment: mechanical filtration).
• In the second container (with cap) a decantation will be made, only by gravity. It is important that the communication conduit to the third container is placed in the upper part, so that in this way the cleaner water will go to the next container.
• In the third container (with cap), the flocculation process will take place, it is added drop wise to aluminium sulphate until the flocks are formed, which will be falling to the bottom. It is important to place the communication channel with the next container on the top of the container.
• In the fourth container (also with cap), the last filtration process is done through filters made with sand in the bottom and on the top gravel. Instead of plug it will be a gauze filter serving also to prevent sand from falling.
• The circulating water will fall into the last vessel (without cap), wherein the biological treatment is performed. Few drops of bleach be poured, in order to much of the microorganisms.
NOTE: The purpose of the container with cap is to allow funds to be cleaned, , as in the treatment plants.

The experiment allows them to understand the operation of a water-purification plant and may encourage responsible consumption and reject behaviour that reduces water quality.