Different Concentrations Of Salt Research Articles

An analytical solution model of oil–water dynamic imbibition considering dynamic contact angle effect and osmotic pressure at micro-nano scale

Spontaneous imbibition is one of the important mechanisms to enhance oil recovery during hydraulic fracturing process of shale reservoirs. The dynamic contact angle effect in imbibition kinetics of liquid–liquid system is complicated due to the large number of micro-nano pores in shale reservoir. Moreover, the content of clay minerals is high, the chemical osmosis effect is significant, and the impact of osmotic pressure on imbibition is not clear. In order to clarify the dynamic contact angle effect in imbibition kinetics and correctly understand the role of osmotic pressure in imbibition process. In this paper, based on the molecular kinetic theory (MKT), the dynamic contact angle effect is successfully coupled with imbibition kinetic equation, and a capillary pressure equation is developed. On the basis, considering the effects of osmotic pressure, external displacement pressure and boundary layer effect on imbibition, An analytical solution model of oil–water dynamic imbibition model is developed. The results shows that under the respective effects of capillary pressure and osmotic pressure, the imbibition velocity initially stabilizes before increasing over time; under the action of displacement pressure, the imbibition velocity increases with time. Imbibition velocity is directly proportional to interfacial tension and capillary radius, but inversely proportional to contact angle and oil viscosity. With the salt concentration difference increasing from 80 mol/m3 to 4710 mol/m3, the imbibition velocity increased by about 54 times. Compared with the membrane efficiency of 30 % and 5 %, the imbibition velocity is increased by 4.95 times. In this work, the dynamic contact angle effect in the imbibition kinetics of liquid–liquid system was accurately characterized, clarified the action mechanism of osmotic pressure, and provided theoretical support for enhancing oil recovery of shale reservoirs.

ГИДРАВЛИЧЕСКИЙ РАСЧЕТ ТРУБОПРОВОДА С РАССРЕДОТОЧЕННЫМ СБРОСОМ РАССОЛА В АКВАТОРИЮ

When producing water using desalination technologies, significant volumes of highly concentrated brines are formed. The solution of the problem of wastes recycling is an important global issue for water protection organizations, and the studies of the last decade confirm this. The article discusses an environmentally friendly method of dispersed uniform brine discharge into the water area, presents the developed technical solution and describes the principle of its operation. As an example, the authors calculate the hole diameters of the distribution pipeline for uniform brine discharge along the length. We calculated the radius and the scattering jet rate at a given distance from the hole in the distribution pipeline. The difference in brine salt concentrations at a depth of 20 m from the discharge point between the background concentration in the sea and the salt concentration was found to be from 0.439 % to 0.524 % along the length of the discharge pipeline. Dissolution of brines to safe concentrations becomes even more intense in the presence of sea currents. The research results can be used in the design and operation of such systems.

Passive interfacial photothermal evaporation and sky radiative cooling assisted all-day freshwater harvesting: System design, experiment study, and performance evaluation

The shortage of freshwater has become a great challenge for the sustainable development of human society. Desalination is considered to be the most practical way to provide a sustainable source of freshwater from seawater, but traditional solar desalination devices usually suffer from the shortcomings of low efficiency and nocturnal failure of freshwater harvesting. In this work, based on the judicious integration of solar-driven interfacial photothermal evaporation (IPTE) and sky radiative cooling (SRC), we design a novel all-day passive freshwater harvesting (FWH) system and carry out a systematic study on its FWH performance, including field experimental tests, performance modeling, and capacity predictions. During the daytime, the seawater is transported to the IPTE layer through the bionic plant water-drawing structure. The IPTE layer absorbs solar energy for seawater evaporation to increase the evaporation efficiency. Meanwhile, by utilizing the salt concentration difference for power generation, we achieve a 64.23% reduction in salt accumulation and a 7.69% enhancement in the seawater evaporation rate. At nighttime, the SRC coating cools the sloping surface and helps to harvest freshwater by condensing the moisture in the air. Outdoor experiment results and numerical prediction results confirm that the proposed system can passively produce freshwater during a 24-h day cycle in an uninterrupted manner, paving a bright future for freshwater resources at no active energy consumption.

Understanding the Effect of Seasonal Climate Variability on the Salinity in Unsaturated Agricultural Soil

Salinization/desalinization processes in the soil vadose zone are important to define agricultural irrigation and drainage schedules, especially in reclaimed crop areas. Numerical modeling of soil–climate interaction is a very helpful tool to understand soil salinity distribution and solute transport and therefore define efficient desalination solutions. A finite element analysis program Code_Bright was used to perform a coupled thermo-chemo-hydraulic analysis aiming at investigating the effect of climate actions on the distribution of soil salinity in depth, by modeling solute transport in the vadose zone under fresh/saline groundwater supply. The analysis separated first the effect of rain infiltration and evaporation, and then a real climate was considered as the boundary condition. A downward flow pattern induced by rainfall in the unsaturated zone resulted in a nonlinear salt leaching process. Significant differences in salt concentration between the surface and lower layer caused by rainfall resulted in a decrement in the leaching efficiency. Evaporation causes water to move upward and salt transport to the surface, thus enhancing the soil salinity above the evaporation front. The salinity above the groundwater table and below the evaporation front were less affected regardless of the salinity of the supplied groundwater. The model simulated the salt leaching process during the wet seasons and salt accumulation processes during the dry ones. The soil salinity and saturation at the soil surface have significantly responded to seasonal climate variability. A typical seasonal climate variability would result in a low salt leaching efficiency through years in the coastal reclamation area. These results would be helpful for the design of soil salinization management strategies, such as reducing salt accumulation by reducing evaporation or leaching the surface salt in the dry season, and increasing the drainage to promote leaching in the wet season.

Control of Osmotic-Engine-Driven Liposomes Using Biological Nanopores

Liposome-based molecular robots that molecular systems are integrated into a giant liposome have been proposed; they are expected to be applied in the fields of medicine, environmental science, food science, and energy science. However, the performance of these molecular robotic components, including intelligence, sensors, and actuators, still hinders their practical use. In particular, the actuators used in the molecular robots, such as molecular motors, do not provide sufficient performance to move the giant liposomes. Hence, we propose an osmotic-engine-driven liposome and demonstrate the migration of liposomes in a microfluidic channel by applying a salt concentration difference between the front and rear of the liposome. Although the migration mechanism is simple and has the potential to provide sufficient mobility performance, control techniques for the movement speed and on/off switching are not established. Herein, we describe a speed control method of osmotic-engine-driven liposomes using pore-forming membrane proteins. In this study, we evaluated the effect of reconstituted α-hemolysin (αHL) nanopores on the water permeability through lipid bilayers. Thereafter, we demonstrated the change in displacement speeds of liposomes with and without nanopores. We expect the speed control method using nanopores to be applied to the liposome-based molecular robots.

Metal Recovery from Natural Saline Brines with an Electrochemical Ion Pumping Method Using Hexacyanoferrate Materials as Electrodes.

The electrochemical ion pumping device is a promising alternative for the development of the industry of recovering metals from natural sources-such as seawater, geothermal water, well brine, or reverse osmosis brine-using electrochemical systems, which is considered a non-evaporative process. This technology is potentially used for metals like Li, Cu, Ca, Mg, Na, K, Sr, and others that are mostly obtained from natural brine sources through a combination of pumping, solar evaporation, and solvent extraction steps. As the future demand for metals for the electronic industry increases, new forms of marine mining processing alternatives are being implemented. Unfortunately, both land and marine mining, such as off-shore and deep sea types, have great potential for severe environmental disruption. In this context, a green alternative is the mixing entropy battery, which is a promising technique whereby the ions are captured from a saline natural source and released into a recovery solution with low ionic force using intercalation materials such as Prussian Blue Analogue (PBA) to store cations inside its crystal structure. This new technique, called "electrochemical ion pumping", has been proposed for water desalination, lithium concentration, and blue energy recovery using the difference in salt concentration. The raw material for this technology is a saline solution containing ions of interest, such as seawater, natural brines, or industrial waste. In particular, six main ions of interest-Na+, K+, Mg2+, Ca2+, Cl-, and SO42--are found in seawater, and they constitute 99.5% of the world's total dissolved salts. This manuscript provides relevant information about this new non-evaporative process for recovering metals from aqueous salty solutions using hexacianometals such as CuHCF, NiHCF, and CoHCF as electrodes, among others, for selective ion removal.

A simple, natural 3D honeycomb structure achieving high photothermal conversion and sustainable salt-resistance for efficient desalination and potential electricity generation

Excellent light absorption and suppressed salt crystallization are required for solar evaporators to operate continuously and efficiently. Herein, we report a waste biomass-derived solar evaporator (Le/CNTs-corn stalk) with natural 3D honeycomb structure and sustainable salt-resistance for efficient desalination and potential electricity generation. This simply fabricated 3D light-absorbing nanostructure greatly increases the light transmission distance, achieving significant boost in light absorption of 94.8 % and photothermal conversion efficiency of 92.5 %. Moreover, a spontaneous salt exchange capability between vascular bundles and laser engraved channels is developed according to the Hagen-Poiseuille's law. Salt concentration difference formed by the volume flowrate is alleviated to facilitate salt dissolution and prevent salt accumulation on the surface, enabling to evaporate effectively for 8 h even in 10 % salt solutions. In addition, tentatively inserted carbon nanotubes on its internal channel surface raises the total zeta potential and causes surface negative charge. A promising electricity generation potential is explored with continually generating a steady voltage of ∼136 mV. Our work provides a sustainable and massive strategy to realize efficient water production and simultaneous electricity generation using sufficient solar energy and biomass resources.

Effect of pH, temperature, and salt concentration on the growth of Bacillus subtilis T9-05 isolated from fish sauce

Biogenic amines (BAs) are organic compounds found in fermented food products, such as sausage, fermented vegetables, wine, and fish sauce. Due to their potential to be harmful to human health and as markers of food quality, BAs content in food can be used as an indicator of food quality and food safety. Some bacteria have the ability to produce or degrade the BAs during fermentation. Environmental conditions can influence the growth of bacteria that produce biogenic amines. The aim of this study was to investigate the growth of Bacillus subtilis T9-05 isolated from fish sauce. Bacillus subtilis T9-05 was grown in tryptic soy broth with the treatment of pH (5, 6, 7, 8, and 9) and salt concentration (0, 1, 3, 6, 9, and 12% (w/v)) and the growing colonies were counted by the total plate count (TPC) method. Bacterial growth was also observed using different temperatures (25°C, 30°C, 35°C, 40°C, and 45°C). Differences in pH conditions and salt concentration significantly affected the growth of Bacillus subtilis T9-05. The highest growth of Bacillus subtilis T9-05 was achieved at pH 7-8 and a salt concentration of 0-1%. Bacillus subtilis T9-05 is classified as halotolerant bacteria. Bacillus subtilis T9-05 could be categorized as mesophilic bacteria based on its optimal growth rate of 35°C.

Effect of Salt Addition and Fermentation Time on Phenolics, Microbial Dynamics, Volatile Organic Compounds, and Sensory Properties of the PDO Table Olives of Gaeta (Italy).

'Oliva di Gaeta' is almost certainly the most important and well-known PDO denomination for table olives in Italy. Their production is based on a specific two-stage trade preparation called the 'Itrana' method. In this work, we investigated how variations in the duration of the initial water fermentation (i.e., 15 and 30 days) and the salt concentration (i.e., 6% and 8% NaCl) influence the chemical features, microbial dynamics, polyphenols, volatile organic compounds, and sensory features of 'Oliva di Gaeta'. The time of the addition of salt did not affect the final concentration in the brine, but a longer initial water fermentation (before salt addition) led to lower pH values. The bacterial count constantly increased until the salt addition (i.e., either 15 or 30 days), while the yeast population peaked on day 30. Generally, the two different salt concentrations did not affect the count of microorganisms at the end of fermentation, with the only exception being a higher lactic acid bacteria count for the treatment with 6% salt added at 30 days. At commercial maturity, the crucial bitter tastant oleuropein was not completely removed from the drupes, and differences in salt concentration and the length of the first-stage water fermentation did not influence its content at the end of olive curing. Richer volatile profiles of olives were detected with higher-salt treatments, while the combination of low salt and early saline treatment provided a more distinct profile. Longer initial water fermentation caused a small increase in some phenolic compounds (e.g., iso-verbascoside, verbascoside, and hydroxytyrosol-glucoside). A panel test indicated that salt application at 30 days resulted in a more "Sour" and "Bitter" taste, irrespective of the salt concentration. The low salt concentration coupled with the late saline treatment resulted in more "Fruity" notes, probably due to the higher production of esters by lactobacilli. The slightly bitter perception of the olives was consistent with the partial removal of oleuropein. Our work revealed the characteristics of the 'Itrana' method and that the variation in salt concentration and its time of application changes parameters ranging from the microbial dynamics to the sensory profile. Specifically, our data indicate that 6% NaCl coupled with a longer initial water fermentation is the most different condition: it is less effective in blocking microbial growth but, at the same time, is more potent in altering the nutritional (e.g., polyphenols) and sensorial qualities (e.g., bitterness and fruitiness) of 'Oliva di Gaeta'.

Sparse multi-nanopore osmotic power generators

Ultrathin nanopore membrane is an emerging energy harvesting system capable of generating electricity from salinity gradients. Here, we report on the evaluation of its practical feasibility by exploring the energy conversion efficiency of single to densely packed multi-pores in a thin silicon nitride. The ionic current characteristics of single pores reveal a quasi-perfect cation selectivity when shrinking the diameter to 20 nm. The perm-selective nanopore is shown to yield osmotic power of 160 pW under a 1,000-fold transmembrane salt concentration difference. Meanwhile, whereas larger energy is gained by parallelly integrating multiple pores, excessive porosity also led to degraded energy conversion efficiency, thereby demonstrating an optimal power density of 100 W per square meter for 100 nm-sized multi-nanopores with a grid spacing of 1 μm. The present findings offer a guide to design highly efficient nanopore membrane osmotic power generators.

Effect of Gaskets Geometry on the Performance of a Reverse Electrodialysis Cell

Salinity gradient energy (SGE) allows the difference in salt concentration in two volumes of water to be harnessed and transformed into clean energy. The most advanced SGE technology is reverse electrodialysis (RED) cells. Recent studies have focused on ways to optimize the flow distribution in the compartments containing the water, for which it is necessary to consider the characteristics of the solutions, the cell dimensions, the operating conditions, as well as their influence on the hydrodynamics and mass transport in the system. In this study, two spacers with different gasket geometry were designed, fabricated, and compared experimentally through voltage and current measurements. The power output was computed, obtaining a maximum power density of 0.14 W/m2. Results show that the geometry of the cell components directly influences the physicochemical principles governing the RED process and is closely related to the cell output parameters. In turn, it is possible to increase the performance of a RED cell by optimizing the gasket geometry by reducing dead zones.

Concrete-structured Nafion@MXene/Cellulose acetate cation exchange membrane for reverse electrodialysis

In a situation facing the limitations of previous renewable energy systems, salinity gradient power (SGP), which is not affected by climate and time, can be a new alternative. SGP can generate electricity by salt concentration difference between two feeds without pollutant emission. One of the representative SGP systems is reverse electrodialysis (RED). An essential part of the RED system is the ion exchange membrane (IEM). However, the research on IEMs for RED, with low areal resistance and high permselectivity, is still lacking. This study proposes a cation exchange membrane (CEM) with engineering nanostructure and introducing new material. Nafion@MXene/Cellulose acetate (CA) composite CEM is fabricated by inspiration from the concrete structure of the building. The electrospun MXene/CA nanofiber is a framework, and the Nafion ionomer is a filler in structure. As a result, the Nafion@MXene/CA CEM shows better physical/electrochemical properties than the casted Nafion and layered membrane. In addition, the Nafion@MXene/CA CEM exhibits a higher power density (2.30 W m −2 ) in the RED system than the commercial membrane, casted Nafion, and layered membrane. High power generation through structural/material engineering. • The MXene/CA nanofiber acts as a framework, and the Nafion ionomer is a filler of the concrete-structured NMC CEM. • The MXene nanosheets improve the physical/electrochemical properties of the cellulose acetate nanofiber-based CEM. • The concrete-structured NMC is strong even if the thickness is reduced due to its unique structure. • High power density (2.30 W m −2 ) was obtained due to the thin membrane and the high permselectivity affected by MXene.

Effect of Salinity on the Imbibition Recovery Process of Tight Sandstone Reservoirs

Fracture network fracturing combined with oil–water infiltration and replacement is an effective approach to develop tight sandstone reservoirs. How to further improve oil recovery based on imbibition is a problem encountered during production. In this study, the core of the CHANG-7 tight sandstone reservoir in the Changqing oilfield of the China National Petroleum Corporation (CNPC) is studied. Combined with the newly designed core self-imbibition experiment, the mechanisms of salinity action are studied, and the influence of salinity on the process of imbibition oil recovery is quantitatively characterized. Research results show that the influence of salinity on the imbibition process of tight sandstone reservoirs takes place mainly through two ways; one is to reduce the oil–water interfacial tension, and the other is to construct an osmotic pressure displacement model. The salinity has significant influences on interfacial tension. The interfacial tension of low-salinity brine is only 1/5 of that of distilled water, but in the presence of high-efficiency surfactants, the influence of the salinity on the interfacial tension can be ignored; the greater the difference in salt concentration, the higher the core permeability and the greater the influence of salinity on the process of imbibition and oil recovery in tight sandstone reservoirs. At the initial stage of imbibition, the effect of salinity is less important than that of capillary force. On the contrary, the effect of salinity is much more important than that of capillary force in the middle of imbibition, and the imbibition curve shows a downward trend. At the later stage of imbibition, the fluid tends toward imbibition equilibrium, and the effects of capillary force and salinity are not obvious.

Growth and physiological response of rice ‘Inpari 35’ under salinity stress and application of silicate fertilizer

Rice is an important staple food in Indonesia. Crop areas can be expanded to boost productivity by utilizing marginal lands, which are saline. This study aims to study the growth and physiological response of rice ‘Inpari 35’ to the application of silicate fertilizer under salinity stress conditions. This study used a completely randomized design (CRD) with two factors. The first factor is the difference in NaCl salt concentration consisting of N0: 0 mM; N1: 37.5 mM; N2: 50 mM, while the second factor is the difference in the concentration of silicate fertilizer (CaSiO3) consisting of S0: 0 mM; S1: 1 mM and S2: 2 mM. Each treatment combination was repeated three times. Observed data were analyzed by analysis of variance (ANOVA). A significant difference between treatments is continued with Duncan's multiple distance test at a 95% confidence level. The results showed that NaCl treatment significantly (p<0.05) inhibited the growth of rice ‘Inpari 35’, which was indicated by a decrease in the plant height and number of leaves. The NaCl treatment caused a reduction in the levels of chlorophyll, carotenoids, proline, membrane stability index (MSI), and relative water content (RWC). The interaction between NaCl treatment and CaSiO3 showed significant differences in physiological parameters by increasing the levels of chlorophyll, carotenoid, proline, membrane stability index, and relative water content.

Osmotic energy harvesting with soft-etched nanoporous polyimide membranes

We present the study of osmotic energy harvesting with soft-etched nanoporous polyimide membranes for a wide range of salt concentration differences, ion irradiation fluences, and multipore orientations (parallel or network). The effect of solution pH and divalent cations on the membrane performance is also investigated. The membrane behavior is evaluated in terms of the reversal potential (Vrev), the maximum power generation (Pmax), and the energy conversion efficiency (ηmax). For an exposed membrane area of ∼1 cm2, the maximum values obtained for these parameters are Vrev = 123 mV, Pmax = 0.45 μW, and ηmax = 40%, respectively. A significant decrease in the membrane performance is observed for membrane samples obtained with ion fluences higher than 4 × 109 ions cm−2 because of pore overlapping and the diffusional resistance of the external solution boundary layers at very low ionic concentrations. The soft-etched membranes are able to hold the reversal potential for several days.

Renewable Power Generation by Reverse Electrodialysis Using an Ion Exchange Membrane.

Reverse electrodialysis (RED) is a promising technology to extract sustainable salinity gradient energy. However, the RED technology has not reached its full potential due to membrane efficiency and fouling and the complex interplay between ionic flows and fluidic configurations. We investigate renewable power generation by harnessing salinity gradient energy during reverse electrodialysis using a lab-scaled fluidic cell, consisting of two reservoirs separated by a nanoporous ion exchange membrane, under various flow rates () and salt-concentration difference (). The current-voltage (I-V) characteristics of the single RED unit reveals a linear dependence, similar to an electrochemical cell. The experimental results show that the change of inflow velocity has an insignificant impact on the I-V data for a wide range of flow rates explored (0.01–1 mL/min), corresponding to a low-Peclet number regime. Both the maximum RED power density () and open-circuit voltage () increase with increasing . On the one hand, the RED cell’s internal resistance () empirically reveals a power-law dependence of . On the other hand, the open-circuit voltage shows a logarithmic relationship of . These experimental results are consistent with those by a nonlinear numerical simulation considering a single charged nanochannel, suggesting that parallelization of charged nano-capillaries might be a good upscaling model for a nanoporous membrane for RED applications.

Centrifugal reverse osmosis (CRO) − a novel energy-efficient membrane process for desalination near local thermodynamic equilibrium

Seawater reverse osmosis (SWRO) can address the global water crisis that is being exacerbated by climate change, industrialization, pollution, and population growth. However, conventional single-stage RO (SSRO) incurs a high energy cost owing to pressurizing the feed to that required for the desired recovery. This cost could be reduced if SWRO were operated at a progressively increasing pressure dictated by thermodynamic equilibrium for the local transmembrane salt-concentration difference. This is approached by the semi-batch closed-circuit RO (CCRO) process that progressively increases the transmembrane pressure (TMP); however, it incurs cumulative energy losses until the pressure is reached for the desired recovery. The centrifugal reverse osmosis (CRO) process uses rotation of a module to create a centrifugal force that increases the TMP differentially with increasing radial distance from the axis-of-symmetry. Unlike CCRO, CRO is a continuous desalination process. A mathematical model and preliminary design are advanced for a CRO module. CRO can reduce the net specific energy consumption relative to SSRO by 31% for 50% recovery at 56 bar from a 35 g/L seawater feed. A TMP progressively increasing from 28 to 56 bar can be achieved with a CRO module having a radius of 0.72 m rotating at 1000 rpm.

Composite hydrogel-based photothermal self-pumping system with salt and bacteria resistance for super-efficient solar-powered water evaporation

Synergistically increasing the solar adsorption/conversion, regulating the water transfer and activation as well as resisting the fouling to enhance the solar-powered interfacial water evaporation performance remains an urgent challenge. Herein, a smart 3D porous photothermal composite hydrogel MoS2@GH, where the antibacterial porous molybdenum disulfide (MoS2) nanoflowers were intercalated between graphene (MoS2@GH) via a simple chemical reduction, was prepared. This cooperated with a controllable self-pumping system of salt concentration differences and liquid level height differences-driven capillary water transfer/transpiration (CHTS) for solar steam generator. In this generator, the hierarchically porous hydrogel not only contributed the light trapping to enhance solar absorption but also generated more dispersed hotspots to access and activate water. Simultaneously, the CHTS system regulated an appropriate water replenishment without direct immersion into bulk water to match the evaporation of hydrogel. As a result, this system can achieve a super-efficient water evaporation rate of 3.2 kg m−2 h−1 under 0.9 sun, and can also delay the salting out fouling and resist the bacterial biofouling. These together with the good thermal and chemical stability of the pure inorganic hydrogel entrust an efficient water desalination, paving a robust way for sustainable clean water production.

A framework for blue energy enabled energy storage in reverse osmosis processes

Reverse osmosis (RO) is perhaps the most promising desalination technology, but it is facing growing economic challenges when coupled to an intermittent energy supply, such as renewable energy-based grids. A technology with similar components to reverse osmosis is pressure retarded osmosis (PRO), which produces energy from differences in salt concentration (blue energy). However, with the increasing cost-competitiveness of wind and solar photovoltaic renewable energy, PRO faces severe technoeconomic challenges as a stand-alone energy technology. To address cost and energy challenges of both RO and PRO, we propose a framework to intermittently operate RO with an instantaneous, electricity-producing PRO mode by taking advantage of the component overlap and existing infrastructure. Here, we analyze the process and component efficiencies associated with a hybridized RO-PRO system and outline the associated technoeconomic limitations. This approach considered operating PRO by mixing seawater RO brine with either RO permeate or a cheap low salinity water source. The results show that a hybridized system may make PRO viable in a niche subset of conditions, including a combination of relatively cheap water (<$1/m3), pricier electricity (>$0.15/kWh), and with electricity pricing schemes having large differences between lowest and highest prices. This hybridization may effectively allow a hybrid PRO-mode system to act as a cheaper, yet less efficient, salinity gradient energy storage mechanism. However, the economics are extremely challenging unless there is inexpensive, or even free, low salinity water source (e.g. treated wastewater) available.

Pengaruh Perbedaan Konsentrasi Garam terhadap Asam Glutamat Terasi Udang Rebon (Acetes sp.)

Udang rebon pada umumnya digunakan sebagai bahan baku produk produk penyedap rasa, antara lain terasi udang, petis, dan diolah menjadi rebon kering. Udang rebon memiliki rasa yang gurih. Fermentasi secara sederhana menghasilkan berbagai produk, salah satunya terasi. Fermentasi garam akan menimbulkan rasa gurih, karena komponen pada udang rebon mengalami pemecahan akibat aktivitas enzim protease. Tujuan penelitian ini adalah untuk menentukan karakteristik terasi berdasarkan perbedaan konsentrasi garam dan menentukan konsentrasi garam terbaik. Metode penelitian menggunakan rancangan acak lengkap. Perlakuan pada penelitian adalah perbedaan konsentrasi garam dengan konsentrasi 2, 8, dan 14%. Parameter yang diamati adalah TPC BAL, pH, aw, kadar garam, asam glutamat, kadar air, dan organoleptik. Data parametrik dianalisis dengan uji ANOVA dan dilanjutkan uji BNJ, sedangkan data non-parametrik dianalisis dengan Kruskal-Wallis dan dilanjutkan dengan uji lanjut Mann-Whitney. Hasil penelitian menunjukkan bahwa terasi udang rebon dengan konsentrasi garam 2, 8, dan 14% mempunyai perbedaan yang nyata (p&lt;5%) terhadap kadar garam, asam glutamat dan kadar air namun tidak mempunyai perbedaan yang nyata (p&gt;5%) terhadap pH dan aw. Formulasi terasi udang rebon terbaik pada penelitian ini dengan penambahan garam 2% dinilai dari asam glutamat 13,68%±0,10 dan uji organoleptik dengan selang kepercayaan 8,61&lt;μ&lt;8,81.