scholarly journals Frontiers in assessing septic systems vulnerability in coastal Georgia, USA: Modeling approach and management implications

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256606
Author(s):  
Nahal Hoghooghi ◽  
J. Scott Pippin ◽  
Brian K. Meyer ◽  
John B. Hodges ◽  
Brian P. Bledsoe
Keyword(s):  
High Water ◽  
Separation Distance ◽  
Septic Tank ◽  
Septic Systems ◽  
Significant Variable ◽  
Septic System ◽  
Minimum Requirement ◽  
Logistic Regression Models ◽  
Significant Research ◽  
Tank Capacity

Threats to public health and environmental quality from septic systems are more prevalent in areas with poorly draining soils, high water tables, or frequent flooding. Significant research gaps exist in assessing these systems’ vulnerability and evaluating factors associated with higher rates of septic systems replacement and repair. We developed a novel GIS-based framework for assessing septic system vulnerability using a database of known septic system specifications and a modified Soil Topographic Index (STI) that incorporates seasonal high groundwater elevation to assess risks posed to septic systems in coastal Georgia. We tested the hypothesis that both the modified STI and septic system specifications such as tank capacity per bedroom and drainfield type would explain most of the variance in septic system repair and replacement using classification inference tree and generalized logistic regression models. Our modeling results indicate that drainfield type (level vs. mounded) is the most significant variable (p-value < 0.001) in predicting septic systems functionality followed by septic tank capacity per bedroom (p-value < 0.01). These show the importance of septic system design regulations such as a minimum requirement for horizontal separation distance between the bottom of trenches and seasonal water table, and adequate tank capacity design. However, for septic systems with a mounded drainfield and a larger tank capacity per bedroom, the modified STI representing hydrological characteristics of septic system location is a significant predictor of a high septic system repair and replacement rate. The methodology developed in this study can have important implications for managing existing septic systems and planning for future development in coastal areas, especially in an environment of rapid climatic change.

scholarly journals Domestic wells have high probability of pumping septic tank leachate

2012 ◽  
Vol 16 (8) ◽  
pp. 2453-2467 ◽  
Author(s):  
J. E. Bremer ◽  
T. Harter
Keyword(s):  
Wastewater Treatment ◽  
Groundwater Flow ◽  
Mass Balance ◽  
High Probability ◽  
Source Area ◽  
Septic Tank ◽  
Septic Systems ◽  
Septic System ◽  
Onsite Wastewater ◽  
Onsite Wastewater Treatment

Abstract. Onsite wastewater treatment systems are common in rural and semi-rural areas around the world; in the US, about 25–30% of households are served by a septic (onsite) wastewater treatment system, and many property owners also operate their own domestic well nearby. Site-specific conditions and local groundwater flow are often ignored when installing septic systems and wells. In areas with small lots (thus high spatial septic system densities), shallow domestic wells are prone to contamination by septic system leachate. Mass balance approaches have been used to determine a maximum septic system density that would prevent contamination of groundwater resources. In this study, a source area model based on detailed groundwater flow and transport modeling is applied for a stochastic analysis of domestic well contamination by septic leachate. Specifically, we determine the probability that a source area overlaps with a septic system drainfield as a function of aquifer properties, septic system density and drainfield size. We show that high spatial septic system density poses a high probability of pumping septic system leachate. The hydraulic conductivity of the aquifer has a strong influence on the intersection probability. We find that mass balance calculations applied on a regional scale underestimate the contamination risk of individual drinking water wells by septic systems. This is particularly relevant for contaminants released at high concentrations, for substances that experience limited attenuation, and those that are harmful even at low concentrations (e.g., pathogens).

scholarly journals Domestic wells have high probability of pumping septic tank leachate

2011 ◽  
Vol 8 (3) ◽  
pp. 5701-5732
Author(s):  
J. E. Horn ◽  
T. Harter
Keyword(s):  
Drinking Water ◽  
Rural Areas ◽  
High Probability ◽  
Transport Model ◽  
Regional Scale ◽  
Septic Tank ◽  
Septic Systems ◽  
Capture Zone ◽  
Septic System ◽  
Water Well

Abstract. Onsite wastewater treatment systems such as septic systems are common in rural and semi-rural areas around the world; in the US, about 25–30 % of households are served by a septic system and a private drinking water well. Site-specific conditions and local groundwater flow are often ignored when installing septic systems and wells. Particularly in areas with small lots, thus a high septic system density, these typically shallow wells are prone to contamination by septic system leachate. Typically, mass balance approaches are used to determine a maximum septic system density that would prevent contamination of the aquifer. In this study, we estimate the probability of a well pumping partially septic system leachate. A detailed groundwater and transport model is used to calculate the capture zone of a typical drinking water well. A spatial probability analysis is performed to assess the probability that a capture zone overlaps with a septic system drainfield depending on aquifer properties, lot and drainfield size. We show that a high septic system density poses a high probability of pumping septic system leachate. The hydraulic conductivity of the aquifer has a strong influence on the intersection probability. We conclude that mass balances calculations applied on a regional scale underestimate the contamination risk of individual drinking water wells by septic systems. This is particularly relevant for contaminants released at high concentrations, for substances which experience limited attenuation, and those being harmful even in low concentrations.

Study of food waste degradation in a simulated septic tank

2019 ◽  
Vol 37 (12) ◽  
pp. 1199-1206
Author(s):  
Hongjian Lin ◽  
Yuchuan Wang ◽  
Leif van Lierop ◽  
Carlos Zamalloa ◽  
Casey Furlong ◽  
...  
Keyword(s):  
Water Quality ◽  
Food Waste ◽  
Sewage Treatment ◽  
Domestic Wastewater ◽  
Lower Percentage ◽  
Septic Tank ◽  
Septic Systems ◽  
Percentage Increase ◽  
Septic System ◽  
The Impact

Septic systems are typically designed to treat domestic wastewater from households without access to centralized facilities. The installation of a food waste disposer (FWD) may increase the discharge of food waste (FW) into the wastewater; therefore, the installation of a FWD is discouraged in households that have a septic system. This study was conducted to determine how a typical dose of FW from a FWD can affect the performance of a septic system in terms of sewage treatment and solids accumulation. A 20-L control tank was compared with an experiment tank to which FW was added, increasing the amount of total suspended solids (TSS) by 31.3% and total chemical oxygen demands by 46.3% for a period of 110 days. Although the influent water quality changed dramatically, the effluent from the experiment tank had a substantially lower percentage increase in water quality parameters compared with the effluent from the control. It was found that in the experiment tank, 75.8% of FW TSS was degraded, whereas only 36.7% of sewage TSS was degraded, and that 18.8% of FW TSS and 44.9% of sewage TSS accumulated in the experiment tank. The addition of FW increased the scum accumulation, even though the dry matter of the scum layer was much less in quantity than the sludge layer. It also increased the lipid content in the sludge. The increase in the scum layer was mainly due to the increase in protein from the addition of the FW. Overall, compared with sewage TSS, FW TSS tends to be more biodegradable, which indicates that the impact on pumping frequency from adding FW will be insignificant.

Smart Sanitary Disposal System in Hard Rock Exposures Using Microbes

2019 ◽  
pp. 684-691
Author(s):  
Ramesh N ◽  
Abdul Bari J ◽  
Ayyappadasan G ◽  
Gunasekar S
Keyword(s):  
Urban Areas ◽  
Anaerobic Bacteria ◽  
Septic Tank ◽  
Septic System ◽  
Septic Tanks ◽  
Clean Environment ◽  
Public Areas ◽  
The Government ◽  
Proper Disposal ◽  
Rate Of Accumulation

Septic system plays a major role in sanitary disposal activities. In developing country it is very essential for proper disposal of wastes for providing clean environment. In our country the government has adopted scheme, “CLEAN INDIA”,. For achieving this aim, the septic system is necessary to construct in each and every residential, commercial buildings and public areas. Septic tank systems are a type of simple onsite sewage facility.But groundwater pollution may occur and can create a problem. Usage of mobile septic tank can be helpful to avoid such problem. In this present investigation an idea has been arrived and the septic tank constructed by the way which have been tested for 10 days for decomposition using microbes. The term ‘septic’ refer to the anaerobic bacteria environment that develops in the tanks which decomposes or mineralizes the water discharged into the tank. The rate of accumulation of sludge is faster than rate of decomposition. So in our project we have used microbes for decomposition.In urban areas, construction of septic tanks are easier. But in rock exposures, the septic tanks cannot be constructed easily. In this paper, the problem is solved by giving an idea as solution by providing a “MOBILE SEPTIC TANK”. This will be helpful and eliminate such problems.    

Effluent tracing and the transport of contaminants from a domestic septic system

2005 ◽  
Vol 51 (10) ◽  
pp. 283-290 ◽  
Author(s):  
P.M. Geary
Keyword(s):  
Riparian Vegetation ◽  
Inorganic Nitrogen ◽  
Sandy Soils ◽  
Inorganic Nutrients ◽  
Septic Systems ◽  
Septic System ◽  
Absorption System ◽  
Conservative Tracer ◽  
Leaching Experiments ◽  
Total Inorganic Nitrogen

A domestic soil absorption system in a coastal location was instrumented with suction lysimeters and piezometers and monitored between August and December 2002. Using the sandy soils from the site, column leaching experiments were also undertaken and these suggested that bromide would be a suitable conservative tracer which could be added to the wastewater system to determine the direction and rate of groundwater flow. The septic system plume boundaries were identified from the monitoring results and the subsurface fate of the inorganic nutrients determines using ion ratios. The tracing results indicated that groundwater was moving at 0.4 m/day towards a nearby drain. The ion ratios indicated that total inorganic nitrogen and orthophosphate were not substantially lost or diluted in the sandy soils downgradient from the soil absorption system, and that without riparian vegetarian lining the drain, these nutrients would have been largely unattenuated in transport. In the absence of adequate vertical and horizontal setback distances, riparian vegetation is regarded as very important in limiting the subsurface transport of inorganic nutrients from domestic septic systems.

Temporal Variability in the Vertical Separation Distance of Septic System Drainfields Along the Southern Rhode Island Coast

2020 ◽  
Vol 231 (3) ◽  
Author(s):  
Alissa H. Cox ◽  
Deborah Surabian ◽  
George W. Loomis ◽  
Jim D. Turenne ◽  
Jose A. Amador
Keyword(s):  
Rhode Island ◽  
Temporal Variability ◽  
Separation Distance ◽  
Vertical Separation ◽  
Septic System ◽  
Island Coast

scholarly journals Tracing Septic Pollution Sources Using Synthetic DNA Tracers: Proof of Concept

2019 ◽  
Vol 12 ◽  
pp. 117862211986379 ◽  
Author(s):  
Christine B Georgakakos ◽  
Paul L Richards ◽  
M Todd Walter
Keyword(s):  
Preferential Flow ◽  
Quantitative Polymerase Chain Reaction ◽  
Breakthrough Curves ◽  
Septic Systems ◽  
Proof Of Concept ◽  
Septic System ◽  
Flow Paths ◽  
Synthetic Dna ◽  
Preferential Flow Paths ◽  
Polymerase Chain

Contamination from septic systems is one of the most difficult sources of nonpoint source (NPS) pollution to quantify. Quantification is difficult in part because locating malfunctioning septic systems within a watershed is challenging. This study used synthetic-DNA-based tracers to track flows from 2 septic systems. Sample DNA was quantified using quantitative polymerase chain reaction (qPCR). This technology could be especially useful for simultaneously assessing multiple septic systems because there are essentially infinite unique combinations of DNA bases such that unique tracers could be engineered for each septic system. Two studies were conducted: the first, to determine whether the tracers move through septic systems (experiment 1), and the second, to determine whether the tracers were detectable at watershed scales (experiment 2). In both cases, clear, although complex, breakthrough curves were detected. Experiment 1 revealed possible preferential flow paths that might not have been otherwise obvious, indicative of short circuiting systems. This proof of concept suggests that these tracers could be applied to watersheds suspected of experiencing NPS septic system pollution.

scholarly journals Investigation of Groundwater Contamination from Septic Tank Siting in Umungasi/Abayi, Abia State

2021 ◽  
pp. 41-48
Author(s):  
K. O. Nkem ◽  
C. L. Eze ◽  
I. U. Ini
Keyword(s):  
Heavy Metals ◽  
Groundwater Contamination ◽  
Water Samples ◽  
Analytical Techniques ◽  
Septic Tank ◽  
Septic Systems ◽  
Permissible Limits ◽  
Physico Chemical ◽  
Borehole Water ◽  
Standard Limit

The investigation of groundwater contamination from septic tank siting was done in Umungasi/Abayi, Abia State. The aim of this study was to investigate the effect of siting septic systems on the quality of groundwater in Umungasi, Abayi, Aba. Twenty (20) water samples were randomly collected from boreholes located less than 30 m away from septic systems in Umungasi, Abayi Aba, Nigeria to determine their physico-chemical and heavy metals characteristics. While three (3) water samples at distances ranging from 60 m from the nearest septic system were sampled for analyses as controls. Standard analytical techniques were employed in the investigation. The result showed that most of the physicochemical parameters analysed in the borehole water samples were within the WHO/SON/NAFDAC recommended limits except for pH in BH4 and BH7 which had values of 6.3 respectively and were not within the WHO/SON/NAFDAC standard limit of 6.5-8.5. Some of the heavy metals analysed during the period of study were within the permissible limits except for iron in BH5 (0.443 mg/L), BH7 (0.367 mg/L), BH8 (0.511 mg/L), BH9 (0.31 mg/L), BH15 (0.41 mg/L), BH16 (0.327 mg/L), BH17 (0.337 mg/L) and BH18 (0.315 mg/L) that were above the permissible limits of WHO standards of 0.3 mg/l. There was no influence of septic tank siting to the boreholes on groundwater quality during the period of study even though the distance of septic tanks from boreholes in the areas investigated did not conform with that recommended by WHO of 30 – 40 m. The contamination is from the general unhygienic condition of the environment.

scholarly journals Landscaping on or near Septic Drain Fields

EDIS ◽  
2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Whitney C Elmore ◽  
William Lester ◽  
James Moll ◽  
Andrea Albertin ◽  
Mary Lusk
Keyword(s):  
Natural Resources ◽  
Rural Areas ◽  
Landscape Management ◽  
Septic Systems ◽  
Extension Agents ◽  
Septic System ◽  
Family Services ◽  
Management Guidance ◽  
Drain Field ◽  
Soil And Water

Septic systems are common throughout most rural areas, and their care and maintenance are essential to the health of people, wildlife, livestock, agricultural commodities, and water resources. One way to ensure optimal performance of your septic system is to landscape appropriately near the drain field. The purpose of this new 3-page publication of the UF/IFAS Department of Soil and Water Sciences is to provide landscape management guidance for septic system drain fields. Information presented here will be useful for homeowners, landscape management professionals, and Extension agents who work in horticulture, natural resources, agriculture, and family services. Written by Whitney C. Elmore, William Lester, James Moll, Andrea Albertin, and Mary Lusk.https://edis.ifas.ufl.edu/ss687

scholarly journals Fecal Indicator Bacteria Transport from Watersheds with Differing Wastewater Technologies and Septic System Densities

2020 ◽  
Vol 10 (18) ◽  
pp. 6525
Author(s):  
Guy Iverson ◽  
Christa Sanderford ◽  
Charles P. Humphrey ◽  
J. Randall Etheridge ◽  
Timothy Kelley
Keyword(s):  
Wastewater Treatment ◽  
Fecal Indicator Bacteria ◽  
Indicator Bacteria ◽  
Septic Systems ◽  
Watershed Scale ◽  
Septic System ◽  
Treatment Technology ◽  
Fecal Indicator ◽  
Bacteria Transport ◽  
Density Threshold

Wastewater contains elevated concentrations of fecal indicator bacteria (FIB). The type of wastewater treatment technology and septic system density may influence the FIB concentration and exports at the watershed scale. The goal of this study was to gain a better understanding of FIB concentrations and exports from watersheds served by conventional septic (CS) systems, sand filter (SF) septic systems, and a municipal sewer (SEW) system. Seven watersheds (3 CS, 3 SF, and 1 SEW) were monitored to quantify FIB concentration and export monthly from April 2015 to March 2016. The type of wastewater treatment did not yield significant differences in FIB concentration or exports when pooling watersheds using similar wastewater treatment. Watersheds with the highest septic densities (approximately 0.4 systems ha−1) contained greater FIB concentrations and exports than watersheds with the lowest (approximately 0.1–0.2 systems ha−1), but only FIB concentrations significantly differed. These findings suggest that when the septic system density exceeds 0.4 systems ha−1, water quality degradation from septic leachate may be observable at the watershed scale, especially in watersheds dominated by residential development. More research is recommended to determine if this density threshold is similar for other water pollutants and/or in watersheds with differing hydrogeological, land use, and wastewater characteristics.

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