Stigmasterol Removal by an Aerobic Treatment System
Soledad Chamorro1,2, Claudia Xavier1,2,3, Gladys Vidal4,5
1Water Research Center for Agriculture and Mining (CRHIAM), ANID Fondap Center, Concepción, Chile.
Methods in Molecular Biology (Clifton, N.J.)
|August 29, 2023
Summary
Kraft mill effluent contains stigmasterol, an endocrine disrupter toxic to aquatic life. Moving bed biofilm reactors (MBBR) effectively remove 100% of stigmasterol, while aerated lagoons and activated sludge show variable removal rates.
Area of Science:
- Environmental Science
- Environmental Chemistry
- Ecotoxicology
Background:
- Kraft mill effluent contains stigmasterol, a phytosterol with endocrine-disrupting properties.
- Stigmasterol exhibits high toxicity to aquatic organisms like Daphnia magna.
- Aerobic biological treatment can paradoxically increase stigmasterol levels, necessitating effective removal strategies.
Purpose of the Study:
- To compare the efficacy of different aerobic biological treatment systems for stigmasterol removal from kraft mill effluent.
- To evaluate the impact of operational parameters like hydraulic retention time and load rate on stigmasterol removal.
- To identify the most efficient treatment technology for mitigating stigmasterol pollution.
Main Methods:
- Comparative study of activated sludge (AS), aerated lagoon (AL), and moving bed biofilm reactors (MBBR).
- Analysis of stigmasterol removal percentages under varying hydraulic retention times and sterol load rates.
- Assessment of phytosterol removal efficiency in treated effluent.
Main Results:
- Aerated lagoons (AL) achieved up to 90% phytosterol removal, with 96% stigmasterol removal at a load rate of 0.6 mg/L·d.
- Low load rates in AL (0.2 mg/L·d) resulted in increased stigmasterol concentrations (29%–37%).
- Activated sludge (AS) removed 65%–87% of stigmasterol at a 3-hour hydraulic retention time.
- Moving bed biofilm reactors (MBBR) demonstrated complete (100%) stigmasterol removal at a 2-day hydraulic retention time.
Conclusions:
- Moving bed biofilm reactors (MBBR) offer the most effective solution for complete stigmasterol removal from kraft mill effluent.
- Aerated lagoons (AL) can be effective but are sensitive to load rates, with potential for stigmasterol accumulation.
- Activated sludge (AS) provides moderate stigmasterol removal, influenced by operational parameters.
Keywords:
Activated sludgeAerated lagoonKraft mill effluentMoving bed biofilm reactorsStigmasterol removalMore Related Videos
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