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WATER TREATMENT - FROM RESERN/OIR TO HOME

We take the water coming from our taps for granted - but what happens to it before it gets there? Here’s how chemistry helps!

COAGULANTS ADOED

SEDIMENTATION

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	CARBON

Water It d'awn from lakę*. or r«łr.wt, or cen be drawn from g^ojrdwater uung borehcie*.

Screcnlng help* to remove larg* matter from the water. tuch as lea.es and rubbtsh. uslng a wire mesh This prewents the debns from ceusng obstruc trans wtthin ttie facłty. makasg treatment oasier.

Coagularas tuch as aluminium tutfate and fernc chloride are irwed Into the water. Thete make partrales of drt and dissolved substances m the water clump together 50 that they cen be ramov#d

Undor tlow mlang. the ckimped part<tes •ncrease m sae. a process caked floccutatron. Most o# them sink to the bottom and form a sludge. which can be removed from the weter. treeted and disposed of

Residua' cwornt o tha MU' ufeguardt aganst pathogens. fluonde can be addcd aftar ehlonnetion to http to prerent tooth ■lecay.

Ch lor me is added to water to Ml bacteria and veuses. preverrt>rg water-borne oseases kke cholera and typhod. Oione can be used nstead of chłonne, and avo<ds disinrfection byprodoctt.

Agents tuch as orthophosphates can be added to the water. particUarfy m e-ees wrth lead ppet These agents form lead-phosphate compleres on the instde of the pipes. stopptng lead getting eito the water

Water that n too acdtc can lead to water p«pe corroslon It can be pessed throogh a filter coneaining crushed Imestone Imairfy celcium carbonate) to raise pH. Acids can be added rf the p*t rs too high

Some partictes remain In the water aft er sedinentatton. these are remoued by fftratran throogh coal. sand. and graoel beds They are cleancd by punpmg air and water backwardt throogh them

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