engineering recuitment GATE CE 2023-24 Test Series Environmental Engineering Sewage Sewage Treatment
The following three stages are known to occur in the biological action involved in the process of sludge digestion:
1. Acid fermentation
2. Alkaline fermentation
3. Acid regression
The correct sequence of three stages is:
1
1, 2, 3
2
1, 3, 2
3
2,1,3
4
3, 1, 2