Direct Brine Research Articles

Leveraging chemical energy for direct brine valorization

Leveraging chemical energy for direct brine valorization

A risk assessment on Zostera chilensis, the last relict of marine angiosperms in the South-East Pacific Ocean, due to the development of the desalination industry in Chile

Seagrasses, which are considered among the most ecologically valuable and endangered coastal ecosystems, have a narrowly limited distribution in the south-east Pacific, where Zostera chilensis is the only remaining relict. Due to water scarcity, desalination industry has grown in the last decades in the central-north coasts of Chile, which may be relevant to address in terms of potential impacts on benthic communities due to their associated high-salinity brine discharges to subtidal ecosystems. In this work, we assessed ecophysiological and cellular responses to desalination-extrapolable hypersalinity conditions on Z. chilensis. Mesocosms experiments were performed for 10 days, where plants were exposed to 3 different salinity treatments: 34 psu (control), 37 psu and 40 psu. Photosynthetic performance, H2O2 accumulation, and ascorbate content (reduced and oxidized) were measured, as well as relative gene expression of enzymes related to osmotic regulation and oxidative stress; these, at 1, 3, 6 and 10 days. Z. chilensis showed a decrease in photosynthetic parameters such as electron transport rate (ETRmax) and saturation irradiance (EkETR) under hypersalinity treatments, while non-photochemical quenching (NPQmax) presented an initial increment and a subsequent decline at 40 psu. H2O2 levels increased with hypersalinity, while ascorbate and dehydroascorbate only increased under 37 psu, although decreased along the experimental period. Increased salinities also triggered the expression of genes related to ion transport and osmolyte syntheses, but salinity-dependent up-regulated genes were mostly those related to the reactive oxygen species metabolism. The relict seagrass Z. chilensis has shown to withstand increased salinities that may be extrapolable to desalination effects in the short-term. As the latter is not fully clear in the long-term, and considering the restricted distribution and ecological importance, direct brine discharges to Z. chilensis meadows may not be recommended.

Chemical and Energy Recovery Alternatives in SWRO Desalination through Electro-Membrane Technologies

Electro-membrane technologies are versatile processes that could contribute towards more sustainable seawater reverse osmosis (SWRO) desalination in both freshwater production and brine management, facilitating the recovery of materials and energy and driving the introduction of the circular economy paradigm in the desalination industry. Besides the potential possibilities, the implementation of electro-membrane technologies remains a challenge. The aim of this work is to present and evaluate different alternatives for harvesting renewable energy and the recovery of chemicals on an SWRO facility by means of electro-membrane technology. Acid and base self-supply by means of electrodialysis with bipolar membranes is considered, together with salinity gradient energy harvesting by means of reverse electrodialysis and pH gradient energy by means of reverse electrodialysis with bipolar membranes. The potential benefits of the proposed alternatives rely on environmental impact reduction is three-fold: (a) water bodies protection, as direct brine discharge is avoided, (b) improvements in the climate change indicator, as the recovery of renewable energy reduces the indirect emissions related to energy production, and (c) reduction of raw material consumption, as the main chemicals used in the facility are produced in-situ. Moreover, further development towards an increase in their technology readiness level (TRL) and cost reduction are the main challenges to face.

Waste Isolation Pilot Plant Performance Assessment: Radionuclide Release Sensitivity to Diminished Brine and Gas Flows to/from Transuranic Waste Disposal Areas

Abstract Waste Isolation Pilot Plant repository releases are evaluated through the application of modified parameters to simulate accelerated creep closure, include capillary pressure effects on relative permeability, and increase brine and gas saturation in the operations and experimental (OPS/EXP) areas. The modifications to the repository model result in increased pressures and decreased brine saturations in waste areas and increased pressures and brine saturations in the OPS/EXP areas. Brine flows up the borehole during a hypothetical drilling intrusion are nearly identical and brine flows up the shaft are decreased. The modified parameters essentially halt the flow of gas from the southern waste areas to the northern nonwaste areas, except as transported through the marker beds and anhydrite layers. The combination of slightly increased waste region pressures and very slightly decreased brine saturations result in a modest increase in spallings and no significant effect on direct brine releases, with total releases from the Culebra and cutting and caving releases unaffected. Overall, the effects on total high-probability mean releases from the repository are insignificant, with total low-probability mean releases minimally increased. It is concluded that the modified OPS/EXP area parameters have an insignificant effect on the prediction of total releases.

Shale swelling/shrinkage and water content change due to imposed suction and due to direct brine contact

Analyses were performed on nine different preserved shales, representing in situ states of 5–15 % water content and 0.13–0.42 void ratio. Under varying total suction (controlled humidity), each shale shows well-defined relationships among suction, volume change, water content and saturation, with the lower-porosity shales undergoing less volume and water content change than the higher-porosity shales. A decrease in in situ porosity is also associated with a much higher native state suction as well as full saturation extending to suction values beyond 40 MPa. Only part of the high suction is due to capillary tension. Under direct brine exposure, the shales almost always swell, even when the brine has an equivalent suction greater than the shale. This is likely due to the reduction in some component of the matric suction. The shale pore water is found to equilibrate with the solute content of the surrounding brine, due to ion diffusion. Much or all of the swelling, and water increase, appears to take place in the clay-bound water and not in the main (free water) pore space. The swelling magnitude is consistent with the amount of water content increase. Swelling usually corresponds to less than one additional water layer being added between the clays. Swelling, and water increase, is very small for the low-porosity shales. Some osmotic effects are observable in all the shales, and cation exchange on the clays also takes place. Swelling is best inhibited with potassium, followed by sodium, followed by calcium, for brines of equal water activity ranging from 0.8 to 0.9.

A Cross-Sectional Study of Intestinal Parasitic Infections in Children in Ghettoed, Diverse and Affluent Communities in Dschang, West Region, Cameroon

Background: There is a paucity of knowledge on the epidemiology of parasitic diseases which remain rampant in the Dschang municipality. Three communities around Dschang town—Ngui (slummy), Paidground (heterogeneous) and the Administrative Quarter-AQ (wealthy) were investigated to highlight the aetiology of intestinal parasitic infections (IPIs) in children in order to enhance health policy intervention priorities. Methods: Between July and November 2009, 31 stools amples were collected from children aged six months to 18 years (mean 9 years) in 295 house-holds across the three communities. A structured questionnaire was used to obtain information on socio-demographic characteristics, source of water supply, de-worming practice and treatment history. Stool samples were screened for ova/larvae of intestinal parasites using direct wet mount, brine floatation and formol-ether sedimentation methods. Results from stool tests and information obtained from questionnaires were analyzed using SPSS. Results: In total, 223 (26.8%) children had single (19.9%) and multiple (7%) infections from seven parasites: the overall prevalence was 34.7%; helminthes 19.3% and protozoa 15.4% (χ2 = 4.3, P Entamoeba histolytica 8.8%, Ascaris lumbricoides 7.5%, Trichuris trichiura 6.8%, Entamoeba coli (5.8%), hookworm 4.6%, Giardia lamblia 0.8% and Vampirolepis (Syn: Hymenolepis) nana 0.4%. Infections were more severe and rates significantly higher in Ngui (45.9%, χ2 = 86.83, P 2 = 111.97, P < 0.0001). Conclusion: Regular sustained synchronized deworming alongside antiprotozoaics, periodic diSagnostics for all children and slummed residents which lend to intestinal protozoa; sanitary inspection of homes and water supplies; adequate drainage and community wastes disposal; and prevention education on hygiene, sanitation, safe water and health were desirable.

Evaluation of technologies for a desalination operation and disposal in the Tularosa Basin, New Mexico

According to the United Nations Environment Programme, one-third of the world's population lives in a situation of water stress. In the case of New Mexico, about 90% of the 1.8 million inhabitants depend on ground brackish water as their only source of potable water in many areas of the state. This report presents a technically-supported, economically-feasible and environmentally friendly proposal to desalinate brackish water to supply potable water to inland, isolated communities in southwest New Mexico. Several existing technologies were reviewed to identify opportunities for optimization by combining them to provide potable water and reduce the waste stream. Alternatives were studied and experimentation was conducted for some of them. The alternatives proposed were the use of natural coagulants for pretreatment, various solar collectors' arrangements for energy supply, reverse osmosis (RO), low temperature multi-effect distillation (LT-MED), multi-stage flash distillation (MSF), solar distillation (SD), and electrodialysis for desalination process; Spirulina cultivation and SD for waste treatment, and deep well injection (DWI) for waste disposal. Some alternatives were eliminated because they are either technologically or economically not feasible for this case and present high environmental impact. Three plant configurations were analyzed. Option A involves using the linear Fresnel systems (LFS) to produce steam for the first effect of a nine-effect evaporation plant. The number of effects was determined to achieve the optimal relation between equipment investment costs and steam production cost. This plant operates 8 h per day with solar energy and the rest of the 24 hour operating time is provided with fossil fuels. The waste produced will be further evaporated with SD to minimize its flow and the concentrated brine will be injected into a deep well. Option B has the same elements as option A, except that it does not consider the SD, but direct brine injection into a deep well. Option C considers the use of SD as the only process for distillation with DWI as the waste disposal method. The selection criteria for the best configuration were optimal use of solar energy resources, minimization of fossil fuel consumption and waste stream generation and disposal. Operation requirements and economic analysis were considered to select a proposal easy to implement and operate in rural isolated communities. For the following reasons option A is the best configuration to cover the necessity of potable water in New Mexico: (A) the plant is easy to construct and operate. In addition, it can handle different ranges of brackish water flow. (B) The 76% water recovery of the system almost matches the recovery achieved in a RO plant (80%), with the advantage that maintenance costs are reduced and treatment flowrates cannot be matched by the RO plant. (C) Use of the LFS reduces the emission of combustion gases to the atmosphere by 33%. This manifests as a positive point in a LCA evaluation. (D) The minimum environmental impact of the process facilitates the public involvement plan (PIP) because it gives the plant an environmentally responsible image in terms of avoiding greenhouse gases emissions. (E) The return on investment (ROI) is 10.2% at a price of $5.00/m 3 of desalinated water, which is superior to the estimated minimum attractive rate of return (MARR) used for LT-MED plants as 9.5% annually.

Salt-water recycling for brine production at road-salt-storage facilities

This research investigates the storm-water quality at road-salt-storage facilities located at Virginia Department of Transportation (VDOT) winter maintenance locations and investigates the feasibility of a sustainable solution to better manage the salt-contaminated storm-water runoff. Collection ponds are currently used at most salt-storage sites to contain highly saline runoff and prevent its release into the environment. During a synoptic, winter-time sampling, chloride-ion concentrations in these ponds were found to be significantly greater than state and federal regulatory guidelines for surface-water-quality criteria, with individual values exceeding 2000 mg/L. The pond water is currently treated as a waste product by VDOT, resulting in significant costs for disposal. However, this saline pond water can potentially be recycled to produce concentrated brine solutions, which can then be used by VDOT for either prewetting dry salt during application to roadways or for direct brine application. Laboratory and field tests have been performed using a bench-scale brine generation system to quantify the effects of hydraulic retention time, temperature, and influent-water quality on system performance. Results of these studies have found that the storm-water runoff captured in collection ponds requires no pretreatment before entering the brine generation system and can effectively produce brine at the target salt concentration. Results of a cost-benefit analysis indicate that it is possible under multiple scenarios to recover the investment capital of implementing brine generation at all VDOT winter maintenance locations, typically within a 4-year horizon. © 2009 American Institute of Chemical Engineers Environ Prog, 2009

Summary discussion of the 1996 performance assessment for the Waste Isolation Pilot Plant

Abstract The Waste Isolation Pilot Plant (WIPP) is under development by the US Department of Energy (DOE) for the geologic disposal of transuranic waste. The construction of complementary cumulative distribution functions (CCDFs) for total radionuclide release from the WIPP to the accessible environment is described. The resultant CCDFs (i) combine releases due to cuttings and cavings, spallings, direct brine release, and long-term transport in flowing groundwater; (ii) fall substantially to the left of the boundary line specified by the US Environmental Protection Agency's (EPA's) standard 40 CFR 191 for the geologic disposal of radioactive waste; and (iii) constitute an important component of the DOE's successful Compliance Certification Application to the EPA for the WIPP. Insights and perspectives gained in the performance assessment (PA) that led to these CCDFs are described, including the importance of: (i) an iterative approach to PA; (ii) uncertainty and sensitivity analysis; (iii) a clear conceptual model for the analysis; (iv) the separation of stochastic (i.e. aleatory) and subjective (i.e. epistemic) uncertainty; (v) quality assurance procedures; (vi) early involvement of peer reviewers, regulators, and stakeholders; (vii) avoidance of conservative assumptions; and (viii) adequate documentation.

Uncertainty and sensitivity analysis for two-phase flow in the vicinity of the repository in the 1996 performance assessment for the Waste Isolation Pilot Plant: undisturbed conditions

Uncertainty and sensitivity analysis results obtained in the 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) are presented for two-phase flow in the vicinity of the repository under disturbed conditions resulting from drilling intrusions. Techniques based on Latin hypercube sampling, examination of scatterplots, stepwise regression analysis, partial correlation analysis and rank transformations are used to investigate brine inflow, gas generation repository pressure, brine saturation and brine and gas outflow. Of the variables under study, repository pressure and brine flow from the repository to the Culebra Dolomite are potentially the most important in PA for the WIPP. Subsequent to a drilling intrusion repository pressure was dominated by borehole permeability and generally below the level (i.e., 8 MPa) that could potentially produce spallings and direct brine releases. Brine flow from the repository to the Culebra Dolomite tended to be small or nonexistent with its occurrence and size also dominated by borehole permeability.

Direct releases to the surface and associated complementary cumulative distribution functions in the 1996 performance assessment for the Waste Isolation Pilot Plant: direct brine release

The following topics related to the treatment of direct brine releases to the surface environment in the 1996 performance assessment for the Waste Isolation Pilot Plant (WIPP) are presented (1) mathematical description of models, (2) uncertainty and sensitivity analysis results arising from subjective (i.e., epistemic) uncertainty for individual releases, (3) construction of complementary cumulative distribution functions (CCDFs) arising from stochastic (i.e., aleatory) uncertainty, and (4) uncertainty and sensitivity analysis results for CCDFs. The presented analyses indicate that direct brine releases do not constitute a serious threat to the effectiveness of the WIPP as a disposal facility for transuranic waste. Even when the effects of uncertain analysis inputs are taken into account, the CCDFs for direct brine releases fall substantially to the left of the boundary line specified in the US Environmental Protection Agency's standard for the geologic disposal of radioactive waste (4O CFR 191.40 CFR 194).

Representation of two-phase flow in the vicinity of the repository in the 1996 performance assessment for the Waste Isolation Pilot Plant

The following topics related to the representation of two-phase (i.e. gas and brine) flow in the vicinity of the repository in the 1996 performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) are discussed: (i) system of nonlinear partial differential equations used to model two-phase flow; (ii) incorporation of repository shafts into model; (iii) creep closure of repository; (iv) interbed fracturing; (v) gas generation; (vi) capillary action in waste; (vii) borehole model; (viii) numerical solution; and (ix) gas and brine flow across specified boundaries. Two-phase flow calculations are a central part of the 1996 WIPP PA and supply results that are subsequently used in the calculation of releases to the surface at the time of a drilling intrusion (i.e. spallings, direct brine releases) and long-term releases due to radionuclide transport by flowing groundwater.