Introduction  of water technology

 

 

Water is very important in human living .It s also universal solvent   and uses for drinking, bathing ,washing, laundering, culinary, heating and air conditioning, irrigation, gardening, industrial processing, power generation ,fishing, swimming, boating and other conventional purposes.

  For the need of consumption  of water and public health issue water treatment is very important .in earliest  days ,ancient peoples used water from directly river ,canals and wells.

When the surface water as from rivers ,canal and lakes were used ,the method used too old but due this most of impurities and contamination of other minerals get effected to health issue and mass of peoples got tremendous deaths of both human and domestic animals also.

 For the purpose of health issue next development of the water purification method  by the process of filtration by allowing water passes through the bed of sand and gravels by which minute suspended and dissolved particles which could not  be removed earlier was caused to be removed. It was found that the process of filtration was gradually improved by pretreatment with certain substances added and get precipitation of impurities present and settled down and removed by settling and sedation by slowly draining sludge. This process of pretreatment is called coagulation which was carried out by ancients by vegetable nirmali but nowadays alum is using for this purpose which is cost effective also .

 This type of pretreated  water passes through filtration process  and  further treatment for disinfection done for removal of bacteria and other germs which prevent from diseases  like cholera ,typhoid and, dysentery etc. Disinfection of water done by chlorination by which using chlorine  or chlorine compound like bleaching powder or ultra-violet rays or excess-lime are also in use nowadays, but in the treatment of large public water supplies,  we still stick to chlorination, being the most effective of all.

                  Thus, it may be seen of what great importance, a public water supply or waterworks system has to be both from the point of view of providing an adequate and reliable supply of water catering to all the public needs and also ensuring that the supplies so made are not only potable but are fully protected against every infection which might otherwise pollute water and cause epidemics resulting in untold human sufferings and loss.

      Further in purification process is developed by using various types of filtration process by using chemical based ion exchange process by using demineralization ,Zeolite  process ,distillation and by evaporation.

Further advance procedure for filtration is developed by scientist by using semipermeable filtration process by using membrane separation procedure by Reverse Osmosis  . This procedure is most popular for saline water purification and used it for further for industrial uses special for power generation from sea water which is available in abundant quantity .It is uses for steam generation and protect boiler from corrosion and deposition of scale.

 

         Sources of water

       Water is required for agricultural ,municipal and industrial purposes. For industrial purposes natural water , may be broadly divided into the following categories.

  1)  Surface waters:

                a)  flowing water e.g., streams and rivers (moorland surface drainage)

                b)  still water e.g., ponds, lake and reservoirs (lowland surface drainage)

  2)  Underground supplies:

                a) water from shallow and deep spring  and wells

                b)  water from lower measures of coal mines.

   3) Rain water

   4  ) Estuarine and sea water

From the point of view of industrial application, it is not usually feasible to use rain water and sea water.

Rain water is irregular in supply and generally expensive to collect Estuarine and sea water are too saline for most industrial uses except cooling. The three main sources of water for industrial use are

               a) Moorland surface drainage.

               b) Lowland surface drainage.

               c) Deep well water.           

The impurities present in water and the extent up to which it is desired to eliminate them in order to required standards of quality. The unit operations in water treatment includes sedimentation with or without flocculation, filtration, chlorination or other methods of disinfection, aeration, water softening, demineralization,  defloridation, and such other combination to suit specific requirement of users. The choices of any particular sequences of treatment units will depend upon the sources of raw water ,quality of treated water and the relative costs, that the set of unit operation in treatment would involve