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Production and basic morphology of struvite crystals from a pilot-scale crystallization process.
1Environmental Engineering Group, Department of Civil Engineering, University of British Columbia, Vancouver, Canada.
Environmental Technology
|March 22, 2006
Summary
This study demonstrates a pilot-scale struvite crystallization process yielding highly pure struvite crystals. Process parameters like retention time and magnesium dosage significantly influenced crystal characteristics for nutrient recovery.
Area of Science:
- Environmental Engineering
- Materials Science
- Chemical Engineering
Background:
- Anaerobic digestion of wastewater generates nutrient-rich supernatants.
- Struvite (magnesium ammonium phosphate) crystallization is a method for nutrient recovery.
- Optimizing struvite precipitation is crucial for efficient phosphorus and nitrogen removal.
Purpose of the Study:
- To evaluate a pilot-scale struvite crystallization process using anaerobic digester supernatants.
- To characterize the purity, size, and morphology of the produced struvite crystals.
- To identify key operational parameters affecting struvite crystal properties.
Main Methods:
- Operation of a pilot-scale struvite crystallization reactor.
- Influent sourced from full-scale anaerobic digester treatment plants.
- Analysis of struvite crystal composition, purity, size, and morphology.
Main Results:
- Produced struvite crystals exhibited high purity (91.2%–94.1%).
- Crystals were easily separated, round, hard, and larger than 1.5 mm.
- Crystal retention time and magnesium dosage significantly impacted crystal size, hardness, and morphology.
Conclusions:
- The pilot-scale process effectively produced high-purity struvite from anaerobic digester supernatants.
- Optimizing reactor retention time and magnesium dosage can control struvite crystal characteristics.
- This method offers a viable route for nutrient recovery and wastewater treatment.