Water And Soft Water Essay

Soft water and hard water are common terms used in households .Most of Earth's water (97%) is in the ocean. Seawater has unique properties: it is saline, its freezing point is

Slightly lower than fresh water, its density is slightly higher, its electrical conductivity is much higher, and it is slightly basic. we cannot used brine water for domestic purpose. So it is needed to convert it into soft water. In this paper we observe the techniques of softening water. Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of approximately 3.5%, or 35 parts per thousand. This means that for every 1 litre (1000 mL) of seawater there are 35 grams of salts (mostly, but not entirely, sodium chloride) dissolved in it.

Key Words: Water softening, Brine

Fresh water also contains some amount of salt dissolved in it.

Treatment Principles:

Household water softeners are ion exchange devices. Ion exchange involves removing the hardness ions calcium and magnesium and replacing them with non-hardness ions, typically sodium supplied by dissolved sodium chloride salt, or brine. The softener contains a micro porous exchange resin, usually sulfonated polystyrene beads that are supersaturated with sodium to cover the bead surfaces. As water passes through this resin bed, calcium and magnesium ions attach to the resin beads and the loosely held sodium is released from the resin into the water. The softening process is illustrated in Figure 1.

After softening a large quantity of hard water the beads become saturated with calcium and magnesium ions. When this occurs, the exchange resin must be regenerated, or recharged. To regenerate, the ion exchange resin is flushed with a salt brine solution (Figure 1). The sodium ions in the salt brine solution are exchanged with the calcium and magnesium ions on the resin and excess calcium and magnesium is flushed out with wastewater.

Pervaporation