Chemical Fate and Transport in a Domestic Septic System: Unsaturated and Saturated Zone Geochemistry

Wilhelm, Sheryl R.; Schiff, Sherry L.; Robertson, W. D.

doi:10.1897/1552-8618(1994)13[193:cfatia]2.0.co;2

Cited by 24 publications

(37 citation statements)

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“…Wilhelm et al (1996) and Robertson (1995), respectively. The ΣPO 4 (aq) boundary concentration is 0.19 mM (5.85 mg L − 1 ), equal to the average measured concentration below the tile bed after 10, 14, 17 (Robertson, 1995) and 12 years (Wilhelm et al, 1994b) of loading. Measured and modelled concentrations along the plume centre line at the non-calcareous site for (e) sorbed P, (f ) strengite (FePO 4 .2H 2 O) and (g) ΣPO 4 (aq).…”

Section: Study Sitesmentioning

confidence: 86%

“…In fact, at the latter site, no P is detected in the groundwater after 1.5 years of infiltration, while after 9 years of operation, the P concentration at 7 m downgradient of the tile field is no more than 0.00065 mM. At Cambridge, the groundwater P concentration below the tile bed varies from 0.16 to 0.23 mM (Wilhelm et al, 1994b;Robertson, 1995), implying a fluctuating effluent source. Phosphorus declines rapidly to background concentrations within the first 10 m along the flow path after 12 years of effluent infiltration (Wilhelm et al, 1994b).…”

Section: Study Sitesmentioning

confidence: 93%

“…The simultaneous decrease of DOC and O 2 with distance from the tile bed is indicative of aerobic DOC degradation in both plumes. At the Cambridge site, the depressed O 2 levels within the plume core (0.03-0.063 mM) contrast with those in the surrounding groundwater, which typically vary from 0.125 to 0.25 mM (Wilhelm et al, 1994b).…”

Section: Study Sitesmentioning

confidence: 98%

“…At Muskoka, the duration of loading is either 1.5 years (DOC and O 2 ) or 9 years (ΣPO 4 (aq)). Up to 90% of the DOC present in the effluent is removed through oxic degradation in the unsaturated soil zone (Wilhelm et al, 1994b). Nevertheless, significant amounts of wastewater DOC reach the water table at both sites.…”

Section: Study Sitesmentioning

confidence: 99%

“…The boundary concentration of ΣPO 4 (aq) is set to 0.0032 mM (0.1 mg L − 1 ). The concentration at x = 0 m refers to the first sampling point below the water table (∼ 1 m and ∼ 0.5 m at the Cambridge and Muskoka sites, respectively; Wilhelm et al, 1994bWilhelm et al, , 1996 underneath the middle of the tile bed. averaged concentrations).…”

Section: Study Sitesmentioning

confidence: 99%

See 4 more Smart Citations

Modelling the geochemical fate and transport of wastewater-derived phosphorus in contrasting groundwater systems

Spiteri

Slomp

Regnier

et al. 2007

Journal of Contaminant Hydrology

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A 1D reactive transport model (RTM) is used to obtain a mechanistic understanding of the fate of phosphorus (P) in the saturated zone of two contrasting aquifer systems. We use the field data from two oxic, electron donor-poor, wastewater-impacted, sandy Canadian aquifers, (Cambridge and Muskoka sites) as an example of a calcareous and non-calcareous groundwater system, respectively, to validate our reaction network. After approximately 10 years of wastewater infiltration, P is effectively attenuated within the first 10 m downgradient of the source mainly through fast sorption onto calcite and Fe oxides. Slow, kinetic sorption contributes further to P removal, while precipitation of phosphate minerals (strengite, hydroxyapatite) is quantitatively unimportant in the saturated zone. Nitrogen (N) dynamics are also considered, but nitrate behaves essentially as a conservative tracer in both systems. The model-predicted advancement of the P plume upon continued wastewater discharge at the calcareous site is in line with field observations. Model results suggest that, upon removal of the wastewater source, the P plume at both sites will persist for at least 20 years, owing to desorption of P from aquifer solids and the slow rate of P mineral precipitation. Sensitivity analyses for the noncalcareous scenario (Muskoka) illustrate the importance of the sorption capacity of the aquifer solids for P in modulating groundwater N:P ratios in oxic groundwater. The model simulations predict the breakthrough of groundwater with high P concentrations and low N:P ratios after 17 years at 20 m from the source for an aquifer with low sorption capacity (b 0.02% w/w Fe(OH) 3 ). In this type of system, denitrification plays a minor role in lowering the N:P ratios because it is limited by the availability of labile dissolved organic matter.

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Section: Study Sitesmentioning

confidence: 86%

Section: Study Sitesmentioning

confidence: 93%

Section: Study Sitesmentioning

confidence: 98%

Section: Study Sitesmentioning

confidence: 99%

Section: Study Sitesmentioning

confidence: 99%

See 3 more Smart Citations

Modelling the geochemical fate and transport of wastewater-derived phosphorus in contrasting groundwater systems

Spiteri

Slomp

Regnier

et al. 2007

Journal of Contaminant Hydrology

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Investigation of an onsite wastewater treatment system in sandy soil: Site characterization and fate of anionic and nonionic surfactants

Nielsen¹,

Decarvalho²,

McAvoy

et al. 2002

Enviro Toxic and Chemistry

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This study reports on the fate of linear alkylbenzene sulfonate (LAS), alcohol ethoxylate (AE), and alcohol ether sulfate (AES) surfactants in a home septic system near Jacksonville (FL, USA) that has been used since 1976. The drainfield at this site resides in fine sand (< 6% silt and clay) with an unsaturated zone that ranges from 0 to 1.3 m. During the wettest times of the year, it is likely that effluent from the septic system passes directly into the groundwater without exposure to an unsaturated zone of soil. Groundwater was collected during two sampling events, representing seasonal high and low groundwater table levels, and analyzed for the surfactants LAS, AES, and AE. During the wet season, the unsaturated zone was approximately 0.01 m beneath the drainfield. During the dry season, the unsaturated zone was about 0.4 m below the drainfield. Alcohol ethoxylate was not detected in any groundwater samples during either sampling. Alcohol ether sulfate was not found in the dry season sampling, but traces of AES had migrated downgradient about 4.7 m horizontally and 1.8 m vertically in the wet season. Linear alkylbenzene sulfonate was detected in some dry season samples and had moved downgradient some 11.7 m horizontally and 3.7 m vertically in the wet season. These observations demonstrate that these surfactants were removed to a great extent; otherwise, they would have traveled more than 260 m downgradient, which is the calculated distance that a conservative tracer like bromide would have moved downgradient over the life of the system. The most likely removal mechanisms for these surfactants were biodegradation and sorption. Therefore, this study indicates that LAS, AE, and AES are readily removed from groundwater in soils below septic system drainfields even in situations with minimal unsaturated soil zones.

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Use of Stable Isotopes to Trace Municipal Wastewater Effluents into Food Webs within a Highly Developed River System

et al. 2014

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Many anthropogenic inputs, such as municipal wastewater effluents (MWWEs), affect stable isotope signatures (δ13C and δ15N) at the base of exposed food webs creating spatial patterns reflecting their incorporation into aquatic food webs. The Grand River in southern Ontario, Canada, is a heavily modified, rapidly urbanizing river that assimilates wastewater from 30 municipal wastewater treatment plants. Stable isotope analysis was applied to resident aquatic invertebrates and fish influenced by three different wastewater outfalls in early, middle, and late summer to determine how values shifted seasonally and with differing effluent quality. There was a slight increase in δ13C in both invertebrates and fish in late summer downstream from the three outfalls, but it is difficult to separate effects of the effluents from downstream gradients. Downstream of two of the three outfalls, the δ15N tended to increase relative to upstream, while the remaining effluent, of the poorest quality, decreased δ15N values of both invertebrates and fish. Spatial trends in stable isotopes became more pronounced as the summer progressed with the greatest between‐site differences occurring in late summer. This study reflects the complex nutrient dynamics associated with MWWE inputs to rivers and contributes to our understanding and application of stable isotope analysis in impacted lotic ecosystems. Copyright © 2014 John Wiley & Sons, Ltd.

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Chemical Fate and Transport in a Domestic Septic System: Unsaturated and Saturated Zone Geochemistry

Cited by 24 publications

References 0 publications

Modelling the geochemical fate and transport of wastewater-derived phosphorus in contrasting groundwater systems

Modelling the geochemical fate and transport of wastewater-derived phosphorus in contrasting groundwater systems

Investigation of an onsite wastewater treatment system in sandy soil: Site characterization and fate of anionic and nonionic surfactants

Use of Stable Isotopes to Trace Municipal Wastewater Effluents into Food Webs within a Highly Developed River System

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