Question

Design a Rapid Sand filter for a population of 1, 00,000 with water supply of 220 lit/head/day. Also design under drainage system and wash water troughs Assume data if necessary.​

Answer 1

Answer:

Solution:

Year

Population: (thousands)

Increment per Decade

Incremental Increase

Percentage Increment per Decade

1901

60

-

-

-

1911

65

+5

-

(5+60) x100=+8.33

1921

63

-2

-3

(2+65) x100=-3.07

1931

72

+9

+7

(9+63) x100=+14.28

1941

79

+7

-2

(7+72) x100=+9.72

1951

89

+10

+3

(10+79) x100=+12.66

1961

97

+8

-2

(8+89) x100=8.98

1971

120

+23

+15

(23+97) x100=+23.71

Net values

1

+60

+18

+74.61

Averages

-

8.57

3.0

10.66

+=increase; - = decrease

Arithmetical Progression Method:

Pn = P + ni

Average increases per decade = i = 8.57

Population for the years,

1981= population 1971 + ni, here n=1 decade

= 120 + 8.57 = 128.57

1991= population 1971 + ni, here n=2 decade

= 120 + 2 x 8.57 = 137.14

2001= population 1971 + ni, here n=3 decade

= 120 + 3 x 8.57 = 145.71

1994= population 1991 + (population 2001 - 1991) x 3/10

= 137.14 + (8.57) x 3/10 = 139.71