large area is required for construction
maintenance and operation cost are high
BOD removal is very low
none of the above
4.5 to 6.0
6.5 to 8.0
8.5 to 10.0
10.5 to 12.0
percentage of sludge by volume to percentage of suspended solids by weight
percentage of sludge by volume to percentage of total solids by weight
percentage of suspended solids by weight to percentage of sludge by volume
percentage of total solids by weight to percentage of sludge by volume
0 to 50
50 to 150
150 to 350
350 to 500
0
1
infinity