TM 5-814-8
APPENDIX B
WASTEWATER AND SOLIDS HANDLING DESIGN CRITERIA
1. Primary sedimentation.
Surface Loading Rate
Average Design Flow
(gpd/sq ft)
(mgd)
150
0.01
500
0.01 to 0.10
0.10 to 1.00
600
1.00 to 10.0
800
1,000
10.0
Hydraulic detention time = 2 to 2.5 hr.
.
Air supply capacity based on 1,500 cu ft of air per pound of BOD5 applied to the aeration tank.
2. Final clarification
Surface Loading Rate
Average Design Flow
(gpd/sq ft)
(mgd)
100
0.01
300
0.01 to 0.10
400
0.10 to 1.00
500
1.00 to 10.0
600
10.0
3.
Suspended growth vitrification
Hydraulic detention time = 3 to 5 hr at average flow.
.
Overflow rate = 500 to 800 gpd/sq ft.
Diffused air application = 1.0 cu ft/gal
ph = 8.0 to 8.6
4. Granular carbon adsorption
Influent suspended solids concentration less than 50 mg/L
Hydraulic loading = 2 to 10 gpd/sq ft.
Contact time = 18 to 36 min at average flow.
Carbon Requirements:
1. Secondary wastewater treatment: 0.5 to 1.8 lb/1,000 gal
2. Advanced wastewater treatment: 0.25 to 0.35 lb/1,000 gal
5. Multi-media filtration
Application rate = 2 to 10 gpm/sq ft at average flow.
6. Lime clarification
Lime dosage = 150 to 200 mg/L (single stage)
300 to 400 mg/L (two stage)
7. Chlorination
Contact time = 15 to 30 min at 4 hr peak (1.75 times average) flow rate.
Dosage = 15 mg/L for trickling filter effluent.
8 mg/L for activated sludge effluent.
6 mg/L for sand filter effluent.
5 mg/L for multi-media filter effluent.
Anaerobic digestion
Conventional
High Rate
Rate
10- 20
Sludge retention time (days) 30- 60
0.15-0.40
0.03-0.08
Solids loading (lb volatile solids/cu ft/day)
B-1
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