Calculate the amount of lime (85% pure) and soda (95% pure) required to soften one million litre of water which contains CaCO_{3} = 12. 5ppml MgCO_{3} = 8.4ppml

CaCl_{2} = 22.2ppml , MgCl_{2} = 9.5ppml C0_{2} = 33ppml HCI = Z3ppml organic matter= 16.Bppm

#### Solution

lmpurities(mg/lit) |
Multiplication factor |
CaC0_{3} equivalent(mg/lit) |
Requirement |

CaC0_{3}=72.5 |
`100/100` | `12.5xx 100/100 = 12.5 ` | L |

MgC0_{3}=8.4 |
`100/84` | `8.4 xx 100/84= 10` | 2L |

CaCl_{2} = 22.2 |
`100/111` | `22.2 xx 100/111 = 20` | S |

MgCl_{2} = 9.5 |
`100/95` | `9.5 xx 100/95 = 10` | L+S |

C0_{2} = 33 |
`100/44` | `33 xx 100/44=75` | L |

HCl = 7.3 | `100/73` | `7. xx 100/73=10` | L+S |

Nacl does not react with lime and soda.

`LIME=74/100 [caC0_3 "equivalent of " 2 xx MgC0_3 + CaC0_3 + MgCl_2 + HCl+CO_2 ] xx`

`("volume of water")/ 100 xx 100/ (%"purity")`

`74 /100 =xx [2 xx 10 + 12.5 + 10 + 10 + 75] xx 10^6/1000 xx 100/ 85`

= 111000 gms.

`SODA =106/100 [caCO_3 " equivalent of " CaCl_2 + MgCl_2 ] xx ("Volume of water")/ 1000 xx 100/("%purity").`

`= 106/100 [20 + 10] xx 10^6/1000 xx 100/95.`

= 33473.68 qms.

The lime requirement is 111000 gms and soda requirement is 33473.68 gms.