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Published on: March 6, 2017
Bench-scale ozonation study of waste activated sludge.
Richard O Mines1, Laura W Lackey
1Department of Environmental Engineering, Mercer University, Macon, Georgia, USA. mines_ro@mercer.edu
Summary
Ozone treatment effectively reduced total chemical oxygen demand (TCOD) and total solids (TS) in waste activated sludge (WAS). Longer contact times significantly improved solids degradation but increased nitrate and phosphate levels.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Wastewater Management
Background:
- Waste activated sludge (WAS) management is a significant challenge in wastewater treatment.
- Ozonation is an advanced oxidation process with potential for sludge treatment.
- Understanding the impact of ozonation on sludge characteristics is crucial for optimizing treatment.
Purpose of the Study:
- To evaluate the effectiveness of ozonation in treating waste activated sludge (WAS).
- To determine the impact of varying ozone contact times on sludge parameters.
- To assess the removal of key pollutants and changes in sludge properties.
Main Methods:
- Bench-scale ozonation of WAS in a bubble column reactor.
- Two experimental runs with different ozone contact times (9 and 12 days).
- Monitoring of various water quality parameters and sludge characteristics.
Main Results:
- Ozonation significantly reduced Total Chemical Oxygen Demand (TCOD) and Total Solids (TS), with removals up to 99% and 95% respectively.
- Solids degradation rate coefficients (K(D)) increased with ozone contact time.
- Nitrate and phosphate concentrations increased, while unstirred sludge volume index (SVI(u)) initially decreased before increasing with extended ozonation.
Conclusions:
- Ozonation is a viable method for reducing TCOD and TS in WAS.
- Optimizing ozone contact time is essential to balance pollutant removal and sludge property changes.
- Further research is needed to manage nutrient increases and SVI changes during ozonation.
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