Selenium and concomitant anions removal in a fixed bed bioreactor to satisfy drinking water regulations and subsequent stability check of selenium-laden biosludge.
Environ Res
; 262(Pt 2): 119895, 2024 Sep 03.
Article
en En
| MEDLINE
| ID: mdl-39237019
ABSTRACT
This is the first successful report on selenium bio-attenuation to satisfy drinking water regulations as per Indian Standards (10 µg/L) in the presence of concomitant nitrate and sulfate from water sources utilizing a fixed bed bioreactor. The bioreactor was immunized with blended microbial culture and worked in downï¬ow mode under anoxic conditions at 30 ± 2 °C for around 190 days under varying inï¬uent selenate (100-500 µg/L as selenium), nitrate (50 mg/L), sulfate concentrations (as per selenium removal) and necessary dose of acetic acid (as COD, a carbon source) in synthetic groundwater, operated at an empty bed contact time (EBCT) of 45-120 min. After supplying an adequate dosage of sulfate and alteration of EBCT, selenium was found to comply with drinking water regulations and nitrate was completely removed. X-ray diffraction and transmission electron microscopy analyses depicted nanocrystalline selenium sulfides (SeS and SeS2) formation as the possible mechanisms of selenium removal. Extended toxicity characteristic leaching procedure (TCLP) extractions confirmed a maximum selenium leaching of 52 and 282 µg/L during anoxic and oxic extractions, respectively. Long-term column leaching (>3-month equilibration) under aerobic conditions at pH 7 confirmed the produced precipitate to be essentially stable (â¼0.14% Se leaching). This work exhibits the synchronous bioremoval of selenium and its co-anions from contaminated water complying with drinking water standards, and leaving a stable and non-hazardous selenium-laden biosludge.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Environ Res
Año:
2024
Tipo del documento:
Article
Pais de publicación:
Países Bajos