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| Publication: |
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Operation of Municipal Wastewater Treatment Plants
Manual of Practice-MOP 11 Sixth Edition
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| Medium: |
| Download Chapter |
| Pages |
| 69 |
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Water Environment Federation (WEF) |
| Year: |
| 2007 |
| Order No: |
| MOP1131 |
| DOI: |
| 10.2175/1-57278-232-3-31 |
Table of Contents
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Index
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Cover Art
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Frontmatter
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| Order Additional Chapters of MOP 11 |
Order a Hard Copy of MOP 11
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Abstract:
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The aerobic digestion process was initially used in designs for new plants that normally treated waste activated sludge from treatment systems that did not contain a primary settling process; only waste activated or trickling filter sludge, or mixtures of waste activated or trickling filter sludge. Typically. if a primary settling process was incorporated to the design, anaerobic digestion was the process of choice because reliable techniques to thicken and aerobically digest higher than 4% solids were not established at the time.
Because of tighter effluent standards for both nitrogen and phosphorus being enforced in the United States in the late 1990s, primary clarifiers have slowly been eliminated from the process train to preserve a good carbon-to-nitrogen ratio typically required to achieve successful biological nitrogen removal.
As a result of the combination of the new effluent limits and new techniques that provided the capabilities to control aerobic digestion processes and accurately predict the performance of the system, aerobic digestion has become attractive once again. A number of anaerobic digesters have been converted to aerobic digesters because of their relative easy operation, lower equipment cost, and because they can produce a better quality supernatant with lower nitrates and phosphorus, therefore, protecting the liquid side upstream.
An additional benefit of aerobic digestion is the fact that they can achieve comparable volatile solids reduction with shorter retention periods, they have less hazardous cleaning and repairing tasks, and they do not produce an explosive digester gas.
The revised chapter was prepared in response to the new performance requirements of the rules and regulations for beneficial reuse, resulting in the identification of techniques that improved the process performance of aerobic digestion. These techniques are grouped into the following categories: (1) pre-thickening, (2) staged operation, (3) aerobic-anoxic operation, and (4) temperature control. These techniques are explored in depth in this chapter.
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| Member Price: $27.00 |
| List Price: $36.00 |
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©2000 Water Environment Federation