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Titolo:
Numerical simulation of a fine-grained denitrification layer for removing septic system nitrate from shallow groundwater
Autore:
MacQuarrie, KTB; Sudicky, EA; Robertson, WD;
Indirizzi:
Univ New Brunswick, Dept Civil Engn, Fredericton, NB E3B 5A3, Canada Univ New Brunswick Fredericton NB Canada E3B 5A3 cton, NB E3B 5A3, Canada Univ Waterloo, Dept Earth Sci, Waterloo, ON N2L 3G1, Canada Univ WaterlooWaterloo ON Canada N2L 3G1 ci, Waterloo, ON N2L 3G1, Canada
Titolo Testata:
JOURNAL OF CONTAMINANT HYDROLOGY
fascicolo: 1-4, volume: 52, anno: 2001,
pagine: 29 - 55
SICI:
0169-7722(200111)52:1-4<29:NSOAFD>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
VARIABLY-SATURATED FLOW; POROUS-MEDIA; WASTE-WATER; SANDY AQUIFER; CHEMICAL FATE; TANK EFFLUENT; TRANSPORT; NITROGEN; MODEL; OXYGEN;
Keywords:
wastewater; nitrate; denitrification; model; groundwater;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
42
Recensione:
Indirizzi per estratti:
Indirizzo: MacQuarrie, KTB Univ New Brunswick, Dept Civil Engn, POB 4400, Fredericton, NB E3B 5A3, Canada Univ New Brunswick POB 4400 Fredericton NB Canada E3B 5A3
Citazione:
K.T.B. MacQuarrie et al., "Numerical simulation of a fine-grained denitrification layer for removing septic system nitrate from shallow groundwater", J CONTAM HY, 52(1-4), 2001, pp. 29-55

Abstract

One of the most common methods to dispose of domestic wastewater involves the release of septic effluent from drains located in the unsaturated zone. Nitrogen from such systems is currently of concern because of nitrate contamination of drinking water supplies and eutrophication of coastal waters. It has been proposed that adding labile carbon sources to septic distribution fields could enhance heterotrophic denitrification and thus reduce nitrate concentrations in shallow groundwater. In this study, a numerical model which solves for variably saturated flow and reactive transport of multiplespecies is employed to investigate the performance of a drain field designthat incorporates a fine-grained denitrification layer. The hydrogeological scenario simulated is an unconfined sand aquifer. The model results suggest that the denitrification layer, supplemented with labile organic carbon,may be an effective means to eliminate nitrogen loading to shallow groundwater. It is also shown that in noncalcareous. aquifers, the denitrificationreaction may provide sufficient buffering capacity to maintain near neutral pH conditions beneath and down gradient of the drain field. Leaching of excess dissolved organic carbon (DOC) from the denitrification layer is problematic, and causes an anaerobic plume to develop in simulations where the water table is less than 5-6 m below ground surface; this anaerobic plume may lead to other down gradient changes in groundwater quality. A drain field and denitrification layer of smaller dimensions is shown to be just as effective for reducing nitrate, but has the benefit of reducing the excess DOC leached from the layer. This configuration will minimize the impact of wastewater disposal in areas where the water table is as shallow as 3.5 in. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 02:22:33