Q. A waste activated sludge (WAS) is to be blended with green waste (GW). The carbon (C) and nitrogen (N) contents, per kg of WAS and GW, on dry basis are given in the table.
| Parameter | WAS | GW |
| Carbon (g) | 54 | 360 |
| Nitrogen (g) | 10 | 6 |
The ratio of WAS to GW required (up to two decimal places) to achieve a blended C:N ratio of 20:1 on dry basis is
Ans: 1.60 – 1.70
sol:
Carbon content:
54 gm from WAS and 360 gm from GW
Total carbon content = 54 W + 360 G
Nitrogen content:
10 gm from WAS and 6 gm from GW
Total nitrogen content = 10 W + 6 G
C: N ratio to be maintained = 20: 1
