scholarly journals Changes in Pumping-Induced Groundwater Quality Used to Supply a Large-Capacity Brackish-Water Desalination Facility, Collier County, Florida: A New Aquifer Conceptual Model

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1951
Author(s):  
Quillan L. Arico ◽  
Zoie R. Kassis ◽  
Robert G. Maliva ◽  
Weixing Guo ◽  
W. Scott Manahan ◽  
...  
Keyword(s):  
Solute Transport ◽  
Conceptual Model ◽  
Brackish Water ◽  
Transport Model ◽  
The United States ◽  
Lateral Migration ◽  
Aquifer System ◽  
Collier County ◽  
Groundwater Assessment ◽  
Solute Transport Modeling

Brackish-water reverse osmosis (BWRO) desalination facilities are designed to treat feedwater within a fixed range in salinity. If the salinity and ion concentrations of the feedwater rises above the maximum design concentrations, then the plant may ultimately fail. BWRO plants typically use groundwater as a feedwater source. Prior to the process design, a detailed groundwater assessment is made to characterize the source aquifer system and to develop a solute-transport model that is used to project the changes in water quality over the expected useful life of the facility. Solute transport-modeling performed for the Collier County (Florida) South BWRO facility, which was designed to produce 30,303 m3/d with an expansion to 75,758 m3/d, used an aquifer system conceptual model that assumed upwards migration over time of brackish waters with higher salinities into the production zones. This conceptual model is typical of how most BWRO systems developed in the United States operate. The original solute transport model predicted a range of increases in dissolved chloride concentrations over a 20-year period from a low of 5 mg/L/yr, a mid-range of 35 mg/L/yr, and a high range of 85 mg/L/yr. Actual data collected over a 11- to 13.5-year period showed that the dissolved chloride concentration average of the feed water decreased by 16 mg/L/yr. The original conceptual model was found to be inaccurate in that it suggested an upwards recharging system, whereas downward leakage (or perhaps lateral migration) of fresher water appears to be occurring in the system. This is an example of a long-term solute-transport model audit, which is rarely performed, in which a new conceptual model was found to be applicable to an aquifer system used to feed a BWRO facility.

scholarly journals Impacts of Feedwater Quality Change on the Oldest Continuously Operated Brackish-Water Reverse Osmosis Desalination Plant in the United States

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2654
Author(s):  
Jeffrey L. Pearson ◽  
Michael Hegy ◽  
Thomas M. Missimer
Keyword(s):  
Solute Transport ◽  
Reverse Osmosis ◽  
Process Design ◽  
Brackish Water ◽  
The United States ◽  
Transport Models ◽  
Design Modification ◽  
Solute Transport Modeling ◽  
The World ◽  
Tds Concentration

Brackish groundwater is abundant in many coastal zones of the world. The water can be economically treated with low-pressure reverse osmosis. A key issue is the stability of the feedwater pumped from groundwater systems. Commonly, groundwater solute-transport models are used to evaluate the long-term changes in salinity with time that impact brackish-water reverse osmosis (BWRO) desalination system process design. These models are run to assess changes over a 20- to 40-year period. The City of Cape Coral, Florida operates two regional BWRO facilities with the South Plant being the oldest continuously operated system in the world. This facility has a capacity of 68,182 m3/d and can treat raw water with a total dissolved solids (TDS) concentration up to 4000 mg/L. Two solute transport models were constructed to evaluate future salinity change in the groundwater source. The first model conducted in 1991 produced a range of probable changes with a high, most probable (mid), and low range. Actual data confirm the low range of the model produced an accurate result (within 15%) and that the 4000 mg/L threshold would not be exceeded until beyond 2031. The second modeling effort conducted in 2014 suggested that the 4000 mg/L TDS threshold would be reached in 2018, which did not happen. The use of real data and regression analyses for all wells suggests that the 4000 mg/L TDS concentration will not be exceeded until after 2060. Once the TDS threshold is reached, the plant would require a process change to allow treatment of higher TDS water. The current analysis shows that plant process design modification would not be required for up to 40 years into the future. The standard conceptual model assuming predominantly upward recharge during pumping was accurate with the addition of an enhanced zone of leakage caused by a fracture zone or a fault. A key issue that contributed to the success of the facility was the use of groundwater solute transport modeling prior to the final design of the membrane process during plant expansions.

scholarly journals Salinity and modelling of the Annaba aquifer system, North-East of Algeria

2018 ◽  
Vol 37 (1) ◽  
pp. 113-120
Author(s):  
Habiba Majour ◽  
Azzedine Hani ◽  
Larbi Djabri
Keyword(s):  
Steady State ◽  
Solute Transport ◽  
History Matching ◽  
Transport Model ◽  
Water Levels ◽  
Model Verification ◽  
Confined Aquifer ◽  
Deep Aquifer ◽  
Aquifer System ◽  
North East

Abstract The potentiometer area in the Annaba basin, covering an area of 264 km2, has declined considerably since 1995. The analysis of the chronological hydrographs (1991–2009) of the piezometric observations shows that this decline is related to about twenty years (20 years) drought that began in 1991. To synthesize hydrological data and study regional changes in aquifer interactions caused by changes in discharge, and determine the contamination of aquifers by salty intrusion in coastal areas, and making forecasts by the year 2023, a multi-layered transient model as well as a solute transport model has been developed. The groundwater flow was modelled using the finite difference method with a horizontal dimension of 500 × 500 m for the cells. The model consists of two layers, the first corresponding to the alluvial phreatic aquifer and the second to the deep confined aquifer, and is calibrated against the steady state groundwater heads recorded before 1996. Model verification was done by history matching over the period 1991–2009. Under steady-state conditions, the correspondence between simulated and observed water levels is generally good (average difference of 0.4 m). For the deep aquifer, the simulated time-series hydrographs closely match the recorded hydrographs for most of the observation wells. For the alluvial aquifer, the recorded hydrographs cover only a short time period, but they are reproduced. The model indicates that groundwater pumping induced a decrease in natural discharge, a downward leakage in most of the basin and a continual water-level decline. The model has also been applied to the analysis of recharge impact. Simulating the behaviour of the system over the period 1991–2009 without pumping indicated small changes in hydraulic head. These results show that the groundwater reservoir has a low recharge, but excellent hydraulic properties. A solute-transport model was used to study aquifer contamination from salty intrusion in coastal sectors; it was extended to the year 2023 by simulating an optimistic hypothesis that maintains present pumping until 2023. The model indicates that the head decrease of the alluvial phreatic and deep confined aquifers will be 4 m and 5 m respectively. The solute concentration in the deep confined aquifer will increase from 1 gꞏdm−3 (prior 2009) to 5 gꞏdm−3 in 2023.

scholarly journals Palaeohydrogeology and Transport Parameters Derived from 4He and Cl Profiles in Aquitard Pore Waters in a Large Multilayer Aquifer System, Central Australia

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Stacey C. Priestley ◽  
Tavis Kleinig ◽  
Andrew J. Love ◽  
Vincent E. A. Post ◽  
Paul Shand ◽  
...  
Keyword(s):  
Solute Transport ◽  
Pore Water ◽  
Transport Model ◽  
Chloride Concentration ◽  
Pore Waters ◽  
Transport Parameters ◽  
Aquifer System ◽  
Water Composition ◽  
Central Australia ◽  
Upper Aquifer

A study of chloride and 4He profiles through an aquitard that separates the Great Artesian Basin from the underlying Arckaringa Basin in central Australia is presented. The aquitard separates two aquifers with long water residence times, due to low recharge rates in the arid climate. One-dimensional solute transport models were used to determine the advective flux of groundwater across the aquitard as well as establish any major changes in past hydrological conditions recorded by variations of the pore water composition. This in situ study showed that both diffusion and slow downward advection (vz=0.7 mm/yr) control solute transport. Numerical simulations show that an increase in chloride concentration in the upper part of the profile is due to a reduction in recharge in the upper aquifer for at least 3000 years. Groundwater extraction since 2008 has likely increased chloride and 4He concentrations in the lower aquifer by pulling up water from deeper layers; however, there has been insufficient time for upward solute transport into the pore water profile by diffusion against downward advection. The transport model of 4He and chloride provides insight into how the two aquifers interact through the aquitard and how climate change is being recorded in the aquitard profile.

scholarly journals Depletion of groundwater resources under rapid urbanisation in Africa: recent and future trends in the Nairobi Aquifer System, Kenya

2020 ◽  
Vol 28 (8) ◽  
pp. 2635-2656
Author(s):  
Samson Oiro ◽  
Jean-Christophe Comte ◽  
Chris Soulsby ◽  
Alan MacDonald ◽  
Canute Mwakamba
Keyword(s):  
Negative Impact ◽  
Groundwater Resources ◽  
Climatic Data ◽  
Groundwater Abstraction ◽  
Management Scenarios ◽  
Aquifer System ◽  
Groundwater Levels ◽  
Future Evolution ◽  
Level Data ◽  
Groundwater Assessment

AbstractThe Nairobi volcano-sedimentary regional aquifer system (NAS) of Kenya hosts >6 M people, including 4.7 M people in the city of Nairobi. This work combines analysis of multi-decadal in-situ water-level data with numerical groundwater modelling to provide an assessment of the past and likely future evolution of Nairobi’s groundwater resources. Since the mid-1970s, groundwater abstraction has increased 10-fold at a rate similar to urban population growth, groundwater levels have declined at a median rate of 6 m/decade underneath Nairobi since 1950, whilst built-up areas have increased by 70% since 2000. Despite the absence of significant trends in climatic data since the 1970s, more recently, drought conditions have resulted in increased applications for borehole licences. Based on a new conceptual understanding of the NAS (including insights from geophysics and stable isotopes), numerical simulations provide further quantitative estimates of the accelerating negative impact of abstraction and capture the historical groundwater levels quite well. Analysis suggests a groundwater-level decline of 4 m on average over the entire aquifer area and up to 46 m below Nairobi, net groundwater storage loss of 1.5 billion m3 and 9% river baseflow reduction since 1950. Given current practices and trajectories, these figures are predicted to increase six-fold by 2120. Modelled future management scenarios suggest that future groundwater abstraction required to meet Nairobi projected water demand is unsustainable and that the regional anthropogenically-driven depletion trend can be partially mitigated through conjunctive water use. The presented approach can inform groundwater assessment for other major African cities undergoing similar rapid groundwater development.

scholarly journals Influence of Chemical Osmosis on Solute Transport and Fluid Velocity in Clay Soils

2020 ◽  
Vol 18 (1) ◽  
pp. 232-238
Author(s):  
Zhihong Zhang ◽  
Gailei Tian ◽  
Lin Han
Keyword(s):  
Solute Transport ◽  
Transport Model ◽  
Fluid Velocity ◽  
Diffusion Mechanism ◽  
Clay Material ◽  
Chemical Osmosis ◽  
Advection Diffusion Equation ◽  
Test Study ◽  
Proposed Model ◽  
Membrane Effect

AbstractSolute transport through the clay liner is a significant process in many waste landfills or unmanaged landfills. At present, researchers mainly focus on the test study about semi-membrane property of clay material, however, the influence of chemical osmosis caused by membrane effect on solute transport and fluid velocity is insufficient. In this investigation, based on the classical advection-diffusion equation, a one-dimensional solute transport model for low-permeable clay material has been proposed, in which the coupled fluid velocity related with hydraulic gradient and concentration gradient is introduced, and the semi-membrane effect is embodied in the diffusion mechanism. The influence of chemical osmosis on fluid velocity and solute transport has been analyzed using COMSOL Multiphysics software. The simulated results show that chemical osmosis has a significant retarded action on fluid velocity and pollutant transport. The proposed model can effectively reveal the change in process of coupled fluid velocity under dual gradient and solute transport, which can provide a theoretical guidance for similar fluid movement in engineering.

scholarly journals Gradient Self-Potential Logging in the Rio Grande to Identify Gaining and Losing Reaches across the Mesilla Valley

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1331
Author(s):  
Scott Ikard ◽  
Andrew Teeple ◽  
Delbert Humberson
Keyword(s):  
New Mexico ◽  
Surface Water ◽  
Electric Potential ◽  
Primary Source ◽  
Rio Grande ◽  
The United States ◽  
Aquifer System ◽  
Diversion Dam ◽  
Gains And Losses ◽  
Self Potential

The Rio Grande/Río Bravo del Norte (hereinafter referred to as the “Rio Grande”) is the primary source of recharge to the Mesilla Basin/Conejos-Médanos aquifer system in the Mesilla Valley of New Mexico and Texas. The Mesilla Basin aquifer system is the U.S. part of the Mesilla Basin/Conejos-Médanos aquifer system and is the primary source of water supply to several communities along the United States–Mexico border in and near the Mesilla Valley. Identifying the gaining and losing reaches of the Rio Grande in the Mesilla Valley is therefore critical for managing the quality and quantity of surface and groundwater resources available to stakeholders in the Mesilla Valley and downstream. A gradient self-potential (SP) logging survey was completed in the Rio Grande across the Mesilla Valley between 26 June and 2 July 2020, to identify reaches where surface-water gains and losses were occurring by interpreting an estimate of the streaming-potential component of the electrostatic field in the river, measured during bankfull flow. The survey, completed as part of the Transboundary Aquifer Assessment Program, began at Leasburg Dam in New Mexico near the northern terminus of the Mesilla Valley and ended ~72 kilometers (km) downstream at Canutillo, Texas. Electric potential data indicated a net losing condition for ~32 km between the Leasburg Dam and Mesilla Diversion Dam in New Mexico, with one ~200-m long reach showing an isolated saline-groundwater gaining condition. Downstream from the Mesilla Diversion Dam, electric-potential data indicated a neutral-to-mild gaining condition for 12 km that transitioned to a mild-to-moderate gaining condition between 12 and ~22 km downstream from the dam, before transitioning back to a losing condition along the remaining 18 km of the survey reach. The interpreted gaining and losing reaches are substantiated by potentiometric surface mapping completed in hydrostratigraphic units of the Mesilla Basin aquifer system between 2010 and 2011, and corroborated by surface-water temperature and conductivity logging and relative median streamflow gains and losses, quantified from streamflow measurements made annually at 16 seepage-measurement stations along the survey reach between 1988 and 1998 and between 2004 and 2013. The gaining and losing reaches of the Rio Grande in the Mesilla Valley, interpreted from electric potential data, compare well with relative median streamflow gains and losses along the 72-km long survey reach.

scholarly journals The Feasibility of Renewable Natural Gas in New Jersey

2021 ◽  
Vol 13 (4) ◽  
pp. 1618
Author(s):  
Anneliese Dyer ◽  
Amelia Christine Miller ◽  
Brianna Chandra ◽  
Juan Galindo Maza ◽  
Carley Tran ◽  
...  
Keyword(s):  
New Jersey ◽  
Natural Gas ◽  
Conceptual Model ◽  
Greenhouse Gas Emission ◽  
Wastewater Treatment Plants ◽  
The United States ◽  
Outreach Program ◽  
Financial Barriers ◽  
The Us ◽  
Renewable Natural Gas

With traditional natural gas being one of the top options for heating in the United States and the present threat of climate change, there is a demand for an alternative clean fuel source. A Renewable Natural Gas Implementation Decision-Making Conceptual Model was created to provide a framework for considering the feasibility of renewable natural gas (RNG) projects and applied to New Jersey, specifically investigating landfills and wastewater treatment plants (WWTPs). Data from the US EPA’s Landfill Methane Outreach Program and New Jersey’s Department of Environmental Protection Sewage Sludge databases were used to identify seven landfills and 22 WWTPs as possible locations for RNG projects. Landfills were found to have a higher potential for producing RNG, on average potentially producing enough RNG to heat 12,792 homes per year versus 1227 for the average WWTP. Additionally, landfills, while having higher capital expenses, have lower projected payback periods, averaging 5.19 years compared to WWTP’s 11.78 years. WWTPs, however, generally are located closer to existing natural gas pipelines than landfills and when they produce more than 362 million standard cubic feet per year (MMSCFY) of biogas are financially feasible. RNG projects at Monmouth County Reclamation Center, Ocean County Landfill, and Passaic Valley Sewerage Commission WWTP show the greatest potential. Greenhouse gas emission reductions from RNG projects at these facilities utilizing all available biogas would be 1.628 million metric tons CO2 equivalents per year, synonymous to removing over 351,000 passenger vehicles from the road each year. In addition, expanding federal and state incentives to encompass RNG as a heating fuel is necessary to reduce financial barriers to RNG projects throughout the US. Overall, this paper supports the hypothesized conceptual model in examining the feasibility of RNG projects through examples from New Jersey and confirms the potential for RNG production utilizing existing waste streams.

Sign in / Sign up

Export Citation Format

Share Document