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Effect of pH on anoxic sulfide oxidizing reactor performance
Qaisar Mahmood1, Ping Zheng, Yousaf Hayat
1Department of Environmental Engineering, Zhejiang University, Hangzhou 310029, China.
Bioresource Technology
|August 19, 2007
Summary
The anoxic sulfide oxidizing (ASO) reactor performs optimally between pH 5-11. Acidic conditions (pH 3) severely inhibit bacterial communities, while high bisulfide, nitrite, or sulfate levels also reduce efficiency.
Area of Science:
- Environmental microbiology
- Wastewater treatment engineering
Background:
- Anoxic sulfide oxidizing (ASO) reactors are crucial for removing sulfide from wastewater.
- Understanding the impact of pH on ASO reactor performance is vital for optimizing treatment processes.
Purpose of the Study:
- To evaluate the effects of varying pH levels on the performance of anoxic sulfide oxidizing (ASO) reactors.
- To determine the optimal pH range for efficient sulfide and nitrite removal in ASO systems.
Main Methods:
- ASO reactor performance was assessed across a wide influent pH range (4-11).
- Operational conditions, including loading and hydraulic retention time (HRT) tests, were varied.
- Sulfide and nitrite removal rates, along with sulfate formation, were monitored.
Main Results:
- Sulfide oxidation was partial at pH 7-7.5 during loading and HRT tests.
- Bacterial communities showed higher sensitivity to acidic pH (e.g., pH 3) than alkaline conditions.
- Inhibition of sulfide oxidation occurred under highly acidic and alkaline conditions due to high dissolved bisulfide ions, nitrite, and excess sulfate (>300 mg/L).
Conclusions:
- The ASO reactor can be effectively operated within a broad pH range of 5-11, based on sulfide and nitrite removal efficiencies.
- Acidic conditions pose a significant challenge to ASO reactor performance.
- Optimizing influent conditions to manage bisulfide, nitrite, and sulfate levels is important for maintaining efficiency across the operational pH range.
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