Hot Spring Water Research Articles

REMOVING ARSENIC AND FLUORIDE FROM HOT SPRING WATER BY ELECTROLYSIS

Currently in Japan, there are many hot springs containing fluoride and arsenic with high concentration. Although the national minimum effluent standard for arsenic and fluoride is 100 µg/L and 8 mg/L, respectively, they are not applied to the hotels with hot spring since no appropriate treatment techniques are available. The objective of this research is to reduce fluoride and arsenic in hot spring wastewater by using electrolysis technique to meet the national minimum effluent standards. The electrolysis system with an anode bath and a cathode bath separated by a diaphragm was adopted. Fluoride and arsenic co-precipitate with magnesium hydroxide formed in the cathode bath in which pH value increases as the electrolysis progresses. The Gero hot spring containing fluoride and arsenic as 17 mg/L and 120 µg/L, respectively, was used as a model effluent. Since Gero hot spring water contains almost no magnesium, magnesium chloride was added as a magnesium source. The addition of 100-200 mg/L could reduce the fluoride concentration to less than 8 mg/L. The arsenic concentration decreased to less than 10 μg/L. 1040 C/L of electricity was required for the operation. The electrolysis system successfully reduces the fluoride and arsenic concentrations below the national minimum effluent standards.

Paleomagnetism of the Mn wad deposit at Niimi hot springs, Hokkaido, Japan

The Niimi hot springs is located at the foot of Mt. Shyakunage in the active Niseko volcanic area, Hokkaido, Japan. The manganese (Mn) wad deposit was precipitated from the hot spring water by biomineralization processes. However, no precise direct age dates for the diagenesis of such Mn oxides have been reported. Here is reported the first paleomagnetic application to date Mn oxides on 144 disseminated Mn wad and 42 pyroclastic clay specimens. The Mn wad specimens were collected at 14 levels between ∼5.5 and ∼62 cm in thickness on a three-dimensional grid pattern, and the clay specimens were collected at seven levels between 85 and 118 cm in thickness. Alternating field step demagnetization isolates either one or two stable characteristic remanent magnetization (ChRM) components in the Mn wad specimens. The lower coercivity component resides in pseudosingle domain titanomagnetite and shows clustered ChRM directions at each sampling level. Conversely, the higher coercivity component resides in single domain titanomagnetite and shows more random directions. The higher coercivity component is likely carried by pyroclastic fragments that landed on the site. The remanent directions of the clay specimens reside in multidomain magnetite, are less stable, and show a scattered distribution. When the observed ChRM directions of the Mn wad specimens are compared with the paleosecular variation record from Lake Biwa in Japan, the Mn wad deposition records the secular variation and appears to have lasted at least ∼1600 years from ∼3.5 to ∼1.9 kyr BP.

Late-Holocene sedimentation and sodium carbonate deposition in hypersaline, alkaline Nasikie Engida, southern Kenya Rift Valley

Continental rift systems are often characterized by geothermal activity and associated discharge of hot groundwater, which can substantially impact the water, solute and sediment budgets of rift-valley lakes. Hot-spring inflow can result in complex lake hydro- and geochemistry, but also buffers against the desiccation of closed-basin lakes in dry climate regimes. Consequently, hydrothermally fed lakes can potentially provide continuous sedimentary records from regions where other types of paleoenvironmental archives are lacking. This is illustrated by Nasikie Engida, a shallow hypersaline and alkaline (soda) lake in the semiarid Rift Valley of southern Kenya. Here, inflow of hot-spring water has maintained a shallow but permanent water body and continuous deposition of sediments through past climate episodes when many other lakes in the eastern (Gregory) branch of the East African Rift System stood dry. We present the first data on late-Holocene sedimentation in this remarkable lacustrine system, typified by authigenic nahcolite [NaH(CO3)] formation during part of its recorded history. Our data include measurements of bulk-sediment and mineralogical composition, clastic-mineral grain size and magnetic susceptibility. Analytical issues related to the large amount of salts within the sediments, both as crystals and in solution in the pore water, are discussed. We also present exploratory time series of the stable-isotope composition of bulk organic matter and authigenic nahcolite. Core lithostratigraphy and preliminary radiocarbon dating indicate that Nasikie Engida has accumulated finely laminated sediments continuously since ca. 2850 cal year BP, which is remarkable given its current maximum depth of only 1.6 m. Synsedimentary nahcolite appears abruptly ~ 2260 cal year BP and since then has been deposited regularly, in the form of distinct pure layers up to several cm thick. Its formation has been enabled by high pCO2, supplied principally from geothermal sources, accumulating in a high-density brine. Although Nasikie Engida has likely been saline over the entire time span covered by the studied sediment sequence, variation in nahcolite deposition and bulk-sediment composition suggests multi-decadal to centennial oscillations in water-column stability and stream inflow driven by variation in climatic moisture balance. Further analyses of this paleoenvironmental archive may thus produce the first continuous climate-proxy record from a vast dry region of equatorial East Africa. Moreover, Nasikie Engida’s extraordinary setting makes it a unique modern analogue for the interpretation of ancient nahcolite-bearing salt-lake deposits.

Effects of medicinal waters on the UV-sensitivity of human keratinocytes \u2013 a comparative pilot study

Balneotherapy has been used to treat several diseases including locomotor, neurological and dermatological conditions. The basis of the “organic hypothesis” of medical balneology is that medicinal waters, especially thermal spa and hot spring waters, contain a high variability of organic components with possible biological effects, including UV photo-protection. The recent study aims to clarify this effect in a human keratinocyte cell line model. Results confirm that organic-rich extract of selected medicinal waters might protect skin-derived cells from DNA damage. These results give a clinical relevance to medicinal waters or pharmaceutical products prepared from them in preventing the adverse effects of solar or artificial UV radiation on the human skin.

Investigation of the effects of electromagnetic field treatment of hot spring water for scale inhibition using a fibre optic sensor

Treatment with an electromagnetic field, one of the potential techniques to inhibit scale deposition from water, has the advantage of not requiring the addition of any chemicals. Field tests using a fibre optic sensor were conducted to evaluate the effect that the treatment of hot spring water in Matsushiro, Japan with an electromagnetic field had on calcium carbonate scale formation. The optical response to scale deposition recorded by the fibre optic sensor decreased as a consequence of the application of an electromagnetic field, and the effectiveness of scale formation inhibition depended on the frequency of the electromagnetic field. This evidence was compared with results from changes in scale mass measured using the quartz crystal microbalance (QCM) method. Mass increases of the scale formed on the quartz crystal surface in hot spring water were inhibited by electromagnetic field treatment. These results were verified performing a column flow test, whereby the flow rate of hot spring water through a column was measured.

Occurrence and molecular characterisation of Acanthamoeba isolated from recreational hot springs in Malaysia: evidence of pathogenic potential.

This study aimed to identify the Acanthamoeba genotypes and their pathogenic potential in five recreational hot springs in Peninsular Malaysia. Fifty water samples were collected between April and September 2018. Physical parameters of water quality were measured in situ while chemical and microbiological analyses were performed in the laboratory. All samples were filtered through the nitrocellulose membrane and tested for Acanthamoeba using both cultivation and polymerase chain reaction (PCR) by targeting the 18S ribosomal RNA gene. The pathogenic potential of all positive isolates was identified using thermo- and osmotolerance tests. Thirty-eight (76.0%) samples were positive for Acanthamoeba. Water temperature (P = 0.035), chemical oxygen demand (P = 0.026), sulphate (P = 0.002) and Escherichia coli (P < 0.001) were found to be significantly correlated with the presence of Acanthamoeba. Phylogenetic analysis revealed that 24 samples belonged to genotype T4, nine (T15), two (T3) and one from each genotype T5, T11 and T17. Thermo- and osmotolerance tests showed that 6 (15.79%) of the Acanthamoeba strains were highly pathogenic. The existence of Acanthamoeba in recreational hot springs should be considered as a health threat among the public especially for high-risk people. Periodic surveillance of hot spring waters and posting warning signs by health authorities is recommended to prevent disease related to pathogenic Acanthamoeba.

Developing Efficient Thermophilic Cellulose Degrading Consortium for Glucose Production From Different Agro-Residues

In the present study, eleven cellulose degrading bacterial strains were isolated from water and soil samples of hot springs in the Chumathang village, Leh and Ladakh region, India. The isolated strains were identified as Bacillus subtilis, Bacillus aryabhattai, Bacillus stratosphericus, Bacillus altitudinis and Brevibacterium frigoritolerans by biochemical and molecular approaches. All the strains were evaluated for the total cellulase, endoglucanase, exoglucanase, and β-glucosidase enzyme activities. On the basis of overall individual cellulose degrading enzyme activities, three strains were selected to develop consortium to enhance their cellulase enzyme activities. The potent cellulose degraders B. stratosphericus BHUJPV-H5, B. subtilis BHUJPV-H19 and B. subtilis BHUJPV-H12 were selected for the consortium development. The effect of cellulase activities of bacterial strains were evaluated ranged up to 6.06 and 0.72 mg ml-1glucose by agro-residues of sugarcane bagasse and wheat straw, respectively after 1 h of incubation. Total cellulase enzyme activity of consortium was recorded two times higher than the individual organisms. These strains can be used for enhancing bioethanol production from lignocellulosic biomass, which can consequently boost biofuel production industry.

Maruhon Bathhouse

We present a renovation project for a bathhouse at a well-established 400-year-old ryokan (Japanese-style hotel) in Sawatari Onsen, Gunma Prefecture. We strove to create a naturally ventilated quiet space—without a loud whirring fan—using the air flowing along a curved slab in the bath space. We also sought to highlight the transparency of the onsen (hot springs) water by diffusing light throughout the space. In the rest area, the curved slab forms a large backrest, where patrons relax and enjoy the view outside. The curved form of this slab was created through studies on seating comfort by making mockups and through the confirmation of the light environment using 3D computer graphics (3DCG). Furthermore, we confirmed through computational fluid dynamics analysis that the buoyancy-driven ventilation effect was caused by the heat of the hot spring in the bath space and this effect ensures the sufficient air exchange rate.

Genome Sequencing Revealed the Biotechnological Potential of an Obligate Thermophile Geobacillus thermoleovorans Strain RL Isolated from Hot Water Spring.

In the present study, we report the draft genome sequence of an obligate thermophile Geobacillus thermoleovorans strain RL isolated from Manikaran hot water spring located atop the Himalayan ranges, India. Strain RL grew optimally at 70°C but not below 45°C. The draft genome (3.39Mb) obtained by Illumina sequencing contains 138 contigs with an average G + C content of 52.30%. RAST annotation showed that amino acid metabolism pathways were most dominant followed by carbohydrate metabolism. Genome-wide analysis using NCBI's Prokaryotic Genome Annotation Pipeline revealed that strain RL encodes for a cocktail of industrially important hydrolytic enzymes glycoside hydrolase, α-and β-glucosidase, xylanase, amylase, neopullulanase, pullulanase and lipases required for white biotechnology. In addition, the presence of genes encoding green biocatalyst multicopper polyphenol oxidase (laccase) and an anticancer enzyme l-glutaminase reflects the significance of strain RL in gray and red biotechnology, respectively. Strain RL is a thermophilic multi-enzyme encoding bacterium which could be the source for the recombinant production of biotechnologically significant enzymes. In, addition whole cells of strain RL may be usedin bioremediation studies.

MICROBIAL DIVERSITY AND PHYSICO-CHEMICAL ATTRIBUTES OF TWO HOT WATER SPRINGS IN THE GARHWAL HIMALAYA, INDIA

The water samples were collected from two different hot water springs (Ringigad and Saldhar) of the Garhwal Himalaya for a period of two years. During the study period, the water sample was collected two times (June and August) each year for the analysis of physico-chemical attributes and isolated microorganisms including bacteria, archaea and fungi. A total of fifteen physico-chemical parameters were studied during the study period that includes the water temperature, dissolved oxygen, pH, conductivity, free carbondioxide, salinity, total dissolved solids, chlorides, total alkalinity, nitrates, sulphates, phosphates, total hardness, calcium and magnesium. Seven bacterial strains along with four archaeal and three fungal strains were isolated and identified in Ringigad thermal spring with α-diversity of 14. However, the α-diversity in Saldhar thermal spring was recorded to be 12 with six bacterial, three archaeal and three fungal strains. The temperature of water ranged between 820C and 890C for Ringigad and between 870C and 920C for Saldhar.

CLONING OF DNA POLYMERASE-ǀ GENE FROM THERMOPHILIC Bacillus licheniformis STRAIN NWMF1 INTO AN E.coli EXPRESSION SYSTEM

DNA polymerase, catalyze template directed synthesis of DNA from nucleotide triphosphate. Thermostable DNA polymerase-ǀ (DNAP-ǀ) has been a common reagent in molecular biology because of its use in DNA amplification and DNA sequencing by PCR. DNAP-ǀ produced in moderate thermophiles such as Bacillus species may not be suitable for PCR, However, moderately thermophilic DNAP-ǀ from Bacillus has been used in molecular biology techniques such as loop mediated isothermal amplification. It is a low cost alternative to detect certain infectious diseases such as tuberculosis, malaria and can be applied in low/middle income countries. The objective of the study was isolation and cloning of DNAP-ǀ gene from native thermophilic bacterium, Bacillus licheniformis strain NWMF1 and over-expression by using expression host E. coli BL21(DE3)pLysS. A gram +ve endospore forming thermophilic bacterium was isolated from soil near the hot-water springs at Polonnaruwa, Sri Lanka. The identification of Bacillus licheniformis strain NWMF1 was carried out using morphological tests and 16s r.RNA gene sequence analysis. Initially the gene was cloned into pGEMT-easy vector and transformed into E. coli JM109 followed by sequence confirmation and protein blast analysis by NCBI. Thereafter the DNAP-ǀ gene re-cloned into PET28a+ vector and transformed into E. coli BL21(DE3)pLysS expression host. Recombinant E. coli clones were confirmed by colony PCR. Sequence analysis confirmed the presence of the complete gene (2640bp) including start and stop codons. The complete protein sequence consists 879 amino acids. SDS-PAGE and analysis by EXPASy–ProtParam indicated the molecular weight of DNAP-ǀ as ~92 kDa. Polymerase activity of His-tag purified DNAP-ǀ was demonstrated by PCR methodology.

The development of conceptual models for the functioning of geothermal systems using hydrogeological, hydrogeochemical and isotopic data: case studies from Rize (NE Turkey)

The hydrogeological and hydrogeochemical properties and isotopic composition of hot and cold water springs in the Ilicakoy and Ayder geothermal areas were investigated and a conceptual model was developed to explain their function. Characteristics of hot groundwater from the Ilicakoy area were: temperature, 63 °C; EC, 6913 µS/cm; pH, 7.2, DO content, 0.75 mg/L; and water type, Na–Ca–HCO3. Characteristics of hot groundwater from the Ayder area were: temperature, 55 °C; EC, 255 µS/cm; pH, 9.2, DO content, 1.9 mg/L; and water type, Na–Ca–CO3–SO4. Ilicakoy has acidic pH values, while those of the Ayder area are alkaline. Carbon in hot water in both areas was derived from inorganic carbon in groundwater and from CO2 in pore spaces in the unsaturated zone. SO2 in hot water was derived from Cenozoic-aged gypsum. Low tritium and high Cl contents in hot waters indicate deep circulation, and Sr was passed from granitic rocks to waters by simple dissolution. High total alpha and total beta values were obtained in the hot waters from the Ilicakoy geothermal area. Ilicakoy and Ayder geothermal spring formation occurred by infiltration of precipitation through fractures in granitic bedrock from the Kackar granitoid, which forms a regionally significant geothermal reservoir. Water of meteoric origin is heated under by a locally steep geothermal gradient, and it rises through bedrock fractures and re-emerges at the ground surface. In the Ilicakoy and Ayder geothermal fields, which are low temperature geothermal systems, the reservoir rock temperature was 80 °C and 149 °C, respectively.

ОРГАНИЧЕСКОЕ ВЕЩЕСТВО В ГИДРОТЕРМАЛЬНЫХ СИСТЕМАХ ДАЛЬНЕГО ВОСТОКА РАЗНЫХ ТИПОВ И ОБСТАНОВКИ

Актуальность исследования определяется необходимостью изучения состава органического вещества в обитаемой и необитаемой областях гидротермальных систем разных типов. Органические соединения в термальных водах, населенных сообществами термофилов и лишенных жизни (стерильная пароводяная смесь), формируют, соответственно, частный биотический и абиотический круговорот органического вещества. Учитывая слабую изученность данных процессов в дальневосточных гидротермальных системах, изучение состава и генезиса органического вещества в них представляется важным для выявления закономерностей превращения вещества в ходе круговорота. Кроме этого, данные по органическим веществам в обитаемой и необитаемой областях гидротермальных систем имеют значение для региональной экологии и бальнеологии, поскольку термальные воды используются для лечения людей в санаториях и бальнеолечебницах. Цель исследования: провести сравнительный анализ состава органического вещества в разных по типу и обстановкам гидротермальных системах Дальнего Востока и выявить наиболее характерные органические соединения, формирующие частные биотический и абиотический круговороты. Объекты: гидротермальные системы континентальной части юга Дальнего Востока (термальная вода из неглубоких скважин Кульдурского, Анненского и Тумнинского геотермальных месторождений) и полуострова Камчатки (стерильная пароводяная смесь, высокотемпературный раствор и горячие источники Мутновского и Паратунского геотермальных районов). Методы: полевые маршруты, твердофазная экстракция, капиллярная газовая хроматомасс-спектрометрия, расчет индексов нечетности, картографический метод. Результаты. Установлено 210 органических соединений, принадлежащих 22 гомологическим рядам. Характерной чертой всех изученных горячих вод и флюида является преобладание простых углеводородов (предельных и ароматических). В основном только эти компоненты формируют абиогенный круговорот органического вещества во флюиде из необитаемой зоны. В воде горячих источников Камчатки и из неглубоких скважин континентальных термальных полей, кроме простых углеводородов, широко распространены биогенные карбоновые кислоты и их эфиры, а в континентальных термальных водах еще и биогенные альдегиды и терпены. Эти соединения в основном формируют биогенный круговорот органического вещества в гидротермальных системах. Отличием термальных вод и флюида п-ова Камчатка от континентальных терм является более широкое распространение предельных и ароматических углеводородов, спиртов, кетонов, а также наличие изопренов, изоалкенов и циклоалканов. Наиболее разнообразный состав органического вещества наблюдается в термальных водах на континенте. Здесь, наряду с компонентами, найденными в термальных водах Камчатки, присутствуют алкены, диэтоксиалканы, диоксаалканы, азотсодержащие и хлорароматические углеводороды и хиноны.

Medusavirus, a Novel Large DNA Virus Discovered from Hot Spring Water.

Recent discoveries of new large DNA viruses reveal high diversity in their morphologies, genetic repertoires, and replication strategies. Here, we report the novel features of medusavirus, a large DNA virus newly isolated from hot spring water in Japan. Medusavirus, with a diameter of 260 nm, shows a T=277 icosahedral capsid with unique spherical-headed spikes on its surface. It has a 381-kb genome encoding 461 putative proteins, 86 of which have their closest homologs in Acanthamoeba, whereas 279 (61%) are orphan genes. The virus lacks the genes encoding DNA topoisomerase II and RNA polymerase, showing that DNA replication takes place in the host nucleus, whereas the progeny virions are assembled in the cytoplasm. Furthermore, the medusavirus genome harbored genes for all five types of histones (H1, H2A, H2B, H3, and H4) and one DNA polymerase, which are phylogenetically placed at the root of the eukaryotic clades. In contrast, the host amoeba encoded many medusavirus homologs, including the major capsid protein. These facts strongly suggested that amoebae are indeed the most promising natural hosts of medusavirus, and that lateral gene transfers have taken place repeatedly and bidirectionally between the virus and its host since the early stage of their coevolution. Medusavirus reflects the traces of direct evolutionary interactions between the virus and eukaryotic hosts, which may be caused by sharing the DNA replication compartment and by evolutionarily long lasting virus-host relationships. Based on its unique morphological characteristics and phylogenomic relationships with other known large DNA viruses, we propose that medusavirus represents a new family, MedusaviridaeIMPORTANCE We have isolated a new nucleocytoplasmic large DNA virus (NCLDV) from hot spring water in Japan, named medusavirus. This new NCLDV is phylogenetically placed at the root of the eukaryotic clades based on the phylogenies of several key genes, including that encoding DNA polymerase, and its genome surprisingly encodes the full set of histone homologs. Furthermore, its laboratory host, Acanthamoeba castellanii, encodes many medusavirus homologs in its genome, including the major capsid protein, suggesting that the amoeba is the genuine natural host from ancient times of this newly described virus and that lateral gene transfers have repeatedly occurred between the virus and amoeba. These results suggest that medusavirus is a unique NCLDV preserving ancient footprints of evolutionary interactions with its hosts, thus providing clues to elucidate the evolution of NCLDVs, eukaryotes, and virus-host interaction. Based on the dissimilarities with other known NCLDVs, we propose that medusavirus represents a new viral family, Medusaviridae.

Antibiotic resistance and heavy metal tolerance in cultured bacteria from hot springs as indicators of environmental intrinsic resistance and tolerance levels

Antibiotic resistance (AR) in the environment is a growing and global concern for public health, and intrinsic AR from pristine sites untouched by pharmaceutical antibiotics is not commonly studied. Forty aerobic bacteria were isolated from water and sediment samples of hot springs in South Africa. Resistance against ten antibiotics (carbenicillin, gentamicin, kanamycin, streptomycin, tetracycline, chloramphenicol, ceftriaxone, co-trimoxazole, nalidixic acid and norfloxacin) was tested using a standard disk diffusion assay. Resistance to one or two antibiotics were equally found in 37.5%, while the remaining 22% showed complete sensitivity. Intermediate resistance was found for ceftriaxone (52.5%), nalidixic acid (37.5%) and carbenicillin (22.5%), while low levels of resistance were observed for streptomycin (5%) and kanamycin (2.5%), and total sensitivity towards the other antibiotics. Twenty-nine isolates were also tested against eight different heavy-metal salts (Al, Cr, Cu, Fe, Hg, Mn, Ni and Pb) at 10 and 40 mM. All isolates were tolerant and able to grow on ≥2 heavy-metal salts at both concentrations. No association was observed between AR and heavy metal tolerance (HMT). Based on the relatively low AR levels, hot spring sites are pristine environments reflecting baseline levels for comparison to other potentially contaminated groundwater sites.

Food security under unreliable rainfall: the case study of a rural community in Limpopo Province, South Africa

Abstract The present study assessed the use of a geothermal hot spring water flow as an adaptation practice to improve subsistence crop production. The aim of this study is to contribute towards natural resource use and management as an adaptation measure to the problem of rainfall scarcity in subsistence production. Focus group discussions with 45 subsistence farmers were conducted in a community garden in which subsistence crops are grown and maintained through a hot spring irrigation system. The study results show that the farmers are aware that rainfall in Sagole community is becoming scarce. The scarcity of rainfall is impacting negatively on subsistence crop production which is characterised by poor productivity. However, the farmers developed an irrigation system downstream of the geothermal hot spring in which the water is furrowed to the garden to irrigate vegetables and fruits throughout the year.

Identification of novel antimicrobial-producing bacteria from an ancient water source by Oxford Nanopore Whole Genome Sequencing and Natural Product Chemistry

Microbially-derived antimicrobial compounds are a rich source of clinical antibiotic leads. However, discovery rates have declined over the past 40 years due, in part, to high rediscovery rates of known compounds from traditional soil-based screening approaches. In this study, an ancient hot-spring water source was tested for the presence of antimicrobial-producing bacteria using culture techniques which led to isolation of two organisms capable of inhibiting the growth of multiple bacterial species. Oxford Nanopore whole genome sequencing was used to identify these two isolates as being in one of two genera; Streptomyces and Paenibacillus. Bioinformatic analysis revealed both isolates to have multiple novel secondary metabolite gene clusters. Investigations of the Streptomyces sp. by natural product chemistry techniques showed the organism to produce multiple antimicrobial compounds, these were effective methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus. This study underlines the value of investigating non-traditional habitats in the search for novel antibiotic-producing organisms.

In-situ monitoring and quantification of fouling development in membrane distillation by means of optical coherence tomography

Fouling formation in membrane distillation limits process stability and could cause besides wetting a rapid flux decrease making the process inefficient. Process performance is conventionally assessed by flux monitoring. Optical Coherence Tomography (OCT) enables in-situ visualization and quantification of fouling layers dominated by scaling in a fully operated direct contact membrane distillation system (DCMD). This study presents an innovative methodology for 3D dataset analysis allowing for the detection and quantification of predominant scaling on the membrane surface. Defined fouling parameters permit a correlation between process performance indicators, especially flux decrease and quantified fouling layer coverage. Additionally, structural information about the fouling layer was derived from the fouling parameters calculated from OCT C-scans across the feed channel within the flat sheet membrane unit. The method was successfully applied in DCMD of hot spring water, showing a critical fouling ratio between RS = 50–60 µm3/µm2, resulting in an overall flux decrease of 80%. The consideration of covered membrane area in RC proved the correlation of increasing fouling layer coverage (up to 90%) inducing a flux decline (by 80%) verifying the hypothesis, that the share of covered membrane area is the limiting step for MD performance. The presented method was able to link scalable fouling parameters with macroscopic process parameters. Hence making performance monitoring possible while enabling an adapted process control.

Magnetotelluric investigations in the southern end of the Cambay basin (near coast), Gujarat, India

Cambay basin is one of the major onshore oil-bearing sedimentary basins of India situated at its western margin in Gujarat state. The region is seismically active and experiences three devastating earthquakes in the past. The region comes under the seismic zone IV and V and necessitates the extensive geophysical studies in for subsurface characteristics and identification of hidden faults in the region for seismic hazard estimation. A magnetotelluric (MT) survey has carried out in the southwestern part of the Cambay basin to identify the sedimentary thickness, the depth of Deccan trap and for identification of West Cambay margin that passes through the region. The MT data, at 13 stations, in the broad frequency range is acquired along an east-west profile with an inter-station spacing of 2–3 km. After processing and analysis of the data, transfer functions in the period band of 0.001–300 s are used for two-dimensional joint inversion. The resultant structure from the 2-D modeling infers the sedimentary thickness of ~0.5 km. A high conductive zone dipping towards east observed in the eastern part of the profile might be due to the West Cambay fault. Basement fracturing at a depth of 2.5–3.0 km at the central portion of the profile might act as a heat exchanger between the deeper geothermal source and nearby hot water spring.

Experimental study for the small capacity organic Rankine cycle to recover the geothermal energy in Obama hot spring resort area

Thought a waste heat recovery system is one of key technologies for sustainable energy, the initial cost of the system is too expensive to introduce for small and medium-sized companies, such as a Japanese hot spring inn. Since the cost for research and development accounts for a large share of total cost of the system, the cost can be reduced if the system is composed of mass-produced commercial components. In this study, an analytical result and an experimental result for two waste heat recovery cycles composed of components dismounted from a commercial heat pump unit are shown. In the analytical study about a supercritical CO2 Rankine cycle, the thermal efficiency of the cycle was calculated to be 6.77 % if it could be assumed that all of the components delivered the equal performance compared with the original heat pump system. In the experimental study about the Organic Rankine Cycle (ORC) with R245fa which uses the fin-tube heat exchanger dismounted from the heat pump, we found that the air cooled fin-tube heat exchanger performed well at the room temperature and this ORC system had an ability to generate the small amount of positive power from the exhaust heat from hot spring water.