Biosolids Engineering
Authored by a diplomate of the American Academy of Environmental Engineers, this expert guide offers professional help for designing and managing a biosolids program and decreasing the burden on landfills.
TABLE OF CONTENTS Biosolids Engineering
3.6: Problems
3.6 Problems
3.1 The Siaya City Water Reclamation Plant is currently treating 6.0 million gal/day of domestic wastewater using a slow-rate trickling-filter system. The six secondary sedimentation tanks employed at the facility each operates with an average overflow rate of 800 gal/ft 2 day. Given the following laboratory batch flux data, estimate (A) underflow velocity ( U b), (B) limiting solids flux (SF L), (C) maximum underflow solids concentration ( X u), and (D) minimum solids settling area. Assume that the mixed-liquor suspended solids (MLSS) concentration in the trickling-filter effluent has an average concen-
| MLSS (mg/liter) | Flow (ft/h) |
|---|---|
| 600 | 21.2 |
| 1,200 | 21.0 |
| 1,800 | 19.0 |
| 2,500 | 18.0 |
| 3,200 | 17.0 |
| 4,600 | 12.0 |
| 5,800 | 9.0 |
| 6,900 | 6.0 |
| 8,100 | 4.0 |
| 10,000 | 3.0 |
| 13,000 | 1.7 |
| 21,000 | 0.8 |
| 32,000 | 0.4 |
| 45,000 | 0.2 |
| 59,000 | 0.1 |
| 68,000 | 0.05 |
tration of 3100 mg/liter and that the secondary clarification tank recycle ratio ( Q r/ Q ) is 0.8.
3.2 The Bambari Sewer Improvement District has employed a gravity thickener to increase the solids content of its secondary sludge from 1.4 to 5.0 per-
| Solids concentration (mg/liter) | Initial settling velocity (ft/h) |
|---|---|
| 1,800 | 12.0 |
| 2,400 | 11.2 |
| 3,900 | 9.1 |
| 5,600 | 7.2 |
| 7,100 | 4.9 |
| 9,000 | 3.4 |
| 11,200 | 2.0 |
| 14,500 | 1.3 |
| 22,000 | 0.7 |
| 31,000 | 0.4 |
| 44,000 | 0.2 |
| 58,000 | 0.1 |
| 69,000 | 0.05 |
cent solids before pumping the sludge to an aerobic digestion tank. Given the following batch solids flux data, estimate the limiting solids flux, the bulk discharge velocity of the sludge U B ,
Copyright The McGraw-Hill Companies, Inc. 2001 under license agreement with Books24x7
