Water Purification.pptx

What is Water Purification? Water purification is the process of removing undesirable dissolved organic and inorganic materials, microorganisms and suspended particles from water.

The goal is to produce water fit for specific purposes.

What is Membrane Process?  Membrane water treatment is a process that removes unwanted constituents from water.  A membrane is a barrier that allows certain substances to pass through while blocking others.

 Water treatment facilities use various types of membranes and processes to clean surface water, groundwater, and wastewater to produce water for industry and for drinking.

There are two types of Membrane processes. These are : Electrodialysis

Reverses Osmosis

ELECTRODIALYSIS Electro Dialysis (ED) is a membrane process, during which ions are transported through semi permeable membrane, under the influence of an electric potential. Electrodialysis (ED) is used to transport salt ions from one solution through ion-exchange membranes to another solution under the influence of an applied electric potential difference. This is done in a configuration called an electrodialysis cell.

The Electro Dialysis Cell Structure of the ED Cell  The cell consists of a feed (dilute) compartment and a concentrate (brine) compartment formed by an anion exchange membrane and a cation exchange membrane placed between two electrodes.  In almost all practical electrodialysis processes, multiple electrodialysis cells are arranged into a configuration called an electrodialysis stack  with alternating anion and cation exchange membranes forming the multiple electrodialysis cells.

How the Electrodialysis Cell works ??

The Contaminated water enters

ED system separates without phase change, which results in relatively low energy consumption. When brackish water is desalted by ED system, the product water needs only limited pre-treatment. Typically only chlorination for disinfection is required. Because ED system removes only ionised species, it is particularly suitable for separating non-ionised fro ionised components. Osmotic pressure is not a factor in ED system, so the pressure can be used for concentrating salt solutions to 20% or higher.

Organic matter, colloids and SiO2 are not removed by ED system. Feedwater pre-treatment is necessary to prevent ED stacks fouling. Elaborate controls are required, and keeping them at optimum condition ca be difficult. Selection of materials of construction for membranes and stack is important to ensure compatibility with the feed stream.