Ammonium-nitrogen-contaminated groundwater remediation by a sequential three-zone permeable reactive barrier (multibarrier) with oxygen-releasing compound (ORC)/clinoptilolite/spongy iron: column studies.
Environ Sci Pollut Res Int
; 22(5): 3705-14, 2015 Mar.
Article
de En
| MEDLINE
| ID: mdl-25256584
ABSTRACT
A novel sequential permeable reactive barrier (multibarrier), composed of oxygen-releasing compound (ORC)/clinoptilolite/spongy iron zones in series, was proposed for ammonium-nitrogen-contaminated groundwater remediation. Column experiments were performed to (1) evaluate the overall NH4(+)-N removal performance of the proposed multibarrier, (2) investigate nitrogen transformation in the three zones, (3) determine the reaction front progress, and (4) explore cleanup mechanisms for inorganic nitrogens. The results showed that NH4 (+)-N percent removal by the multibarrier increased up to 90.43 % after 21 pore volumes (PVs) at the influent dissolved oxygen of 0.68â¼2.45 mg/L and pH of 6.76â¼7.42. NH4(+)-N of 4.06â¼10.49 mg/L was depleted and NOx(-)-N (i.e., NO3 (-)-N + NO2(-)-N) of 4.26â¼9.63 mg/L was formed before 98 PVs in the ORC zone. NH4(+)-N of ≤4.76 mg/L was eliminated in the clinoptilolite zone. NOx(-)-N of 10.44â¼12.80 mg/L was lost before 21 PVs in the spongy iron zone. The clinoptilolite zone length should be reduced to 30 cm. Microbial nitrification played a dominant role in NH4(+)-N removal in the ORC zone. Ion exchange was majorly responsible for NH4(+)-N elimination in the clinoptilolite zone. Chemical reduction and hydrogenotrophic denitrification both contributed to NOx(-)-N transformation, but the chemical reduction capacity decreased after 21 PVs in the spongy iron.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Polluants chimiques de l'eau
/
Nappe phréatique
/
Assainissement et restauration de l'environnement
/
Composés d'ammonium
Limites:
Animals
Langue:
En
Journal:
Environ Sci Pollut Res Int
Sujet du journal:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Année:
2015
Type de document:
Article
Pays d'affiliation:
Chine