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Ozonation in sequencing batch reactors for reduction of waste solids
Ege Egemen Richardson1, Findlay Edwards, John Hernandez
1Aegean Consulting LLC, Las Cruces, New Mexico 88012, USA. Ege@AegeanC.com
Summary
Ozonation of biomass in sequencing batch reactors (SBRs) reduced waste sludge mass by 29%. This process improved biomass settling but decreased effluent quality due to increased soluble chemical oxygen demand, nitrogen, and phosphorus.
Area of Science:
- Environmental Science
- Chemical Engineering
- Wastewater Treatment
Background:
- Sequencing batch reactors (SBRs) are widely used for wastewater treatment.
- Waste sludge production is a significant operational challenge in SBRs.
- Effective sludge reduction strategies are crucial for sustainable wastewater management.
Purpose of the Study:
- To investigate ozonation as a method to reduce waste sludge mass in SBRs.
- To evaluate the impact of ozonation on intracellular products and biomass properties.
- To assess the trade-offs between sludge reduction and effluent quality.
Main Methods:
- Biomass from laboratory-scale SBRs was treated with ozone (O3) as a cell-lysing agent.
- Ozonation parameters included a specific dosage and duration per cycle.
- Effluent quality parameters such as soluble chemical oxygen demand, total Kjeldahl nitrogen, and total phosphorus were monitored.
Main Results:
- Ozonation reduced waste sludge production by an average of 29%.
- The optimal ozonation rate was determined to be 0.0106 mg O3/mg TSS x h.
- Short-term settling characteristics of the ozonated biomass showed improvement.
- Effluent quality decreased, with increases in soluble chemical oxygen demand, total Kjeldahl nitrogen, and total phosphorus.
Conclusions:
- Ozonation is a viable process modification for significantly reducing sludge mass in SBRs.
- The benefits of sludge reduction must be weighed against the negative impact on effluent quality.
- Further research is needed to optimize ozonation for improved effluent quality while maintaining sludge reduction.
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