Search results for "High pH value"

showing 2 items of 2 documents

Thermomineral waters of Greece: geochemical characterization

2020

75 °C). In terms of pH most results vary from 5.5 to 823 °C) ii) warm (23 40 °C) iii) thermal (40 75 °C) and iv) hyperthermal (&gtfew springs show either very low pH (&lt10) proposing serpentinization processes. Regarding TDS concentrations collected waters can be subdivided into low salinity (up to 1.5 g/L) brackish (up to 20 g/L) and saline (up to 43 g/L). The medium high salinities can be justified by mixing with sea water and/or strong waterrock interaction processes. Isotope composition of O and H ranges from 12.7 to +2.7 ‰ SMOW and from 91 to +12 ‰ SMOW respectively and is generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Only few water samples show a positive shift for δ18O possibly related to high temperature waterrock interaction processes. Carbon dioxide (18 997000 μmol/mol) or N2 (1100 989000 μmol/mol) or CH4 (&ltMany geothermal areas of Greece are located in regions affected by Miocene or Quaternary volcanism and in continental basins characterised by elevated heat flow. Moreover the majority of them is found along the coast as well as in islands of the Aegean Sea and thus thermal water is often brackish to saline due to marine intrusion into costal aquifer. In the present study almost 300 thermal and cold mineral water samples were collected along the Hellenic territory with their physicochemical parameters (temperature pH electrical conductivity and Eh) and the amount of bicarbonates (titration with 0.1N HCl) being determined in situ. Additionally gases found either in free or dissolved phase were sampled. Both water and gas samples were analysed at the INGVPa laboratories for major ions (Ion Chromatography) silica (Inductively Coupled Plasma Optical Emission Spectrometry) chemical composition of free and dissolved gases (Gas Chromatography) water isotopes (O and H) and carbon and helium isotopes of free and dissolved gases (Mass Spectrometry). The temperature of the investigated waters ranges from 6.5 to 98°C pH from 1.96 to 11.98 whilst Total Dissolved Solids (TDS) from 0.06 to 43 g/L. Based on the temperature parameter waters can be divided into four groups: i) cold (&lt0.5 913000 μmol/mol) are the prevailing gas species found in the studied sites. The δ13CCO2 values ranged from 20.1 to +8.5 ‰ whilst the isotope ratio of He from 0.21 to 6.71 R/RA.4) suggesting interaction with H2Srich gases or very high pH values (&gtSettore GEO/08 - Geochimica E Vulcanologia
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Effect of pH and nitrite concentration on nitrite oxidation rate

2011

The effect of pH and nitrite concentration on the activity of the nitrite oxidizing bacteria (NOB) in an activated sludge reactor has been determined by means of laboratory batch experiments based on respirometric techniques. The bacterial activity was measured at different pH and at different total nitrite concentrations (TNO 2). The experimental results showed that the nitrite oxidation rate (NOR) depends on the TNO 2 concentration independently of the free nitrous acid (FNA) concentration, so FNA cannot be considered as the real substrate for NOB. NOB were strongly affected by low pH values (no activity was detected at pH 6.5) but no inhibition was observed at high pH values (activity wa…

Waste component removalPH rangeUnclassified drugRespirometric techniqueLaboratory methodPHOxidation ratesPH valueNitriteSaturation constantBatch reactorPH effectOxidation kineticsDissociation constantNitrobacterKinetic expressionWaste Disposal FluidInhibition constantschemistry.chemical_compoundBacteriumBioreactorsNitrous acidNitriteBacterial activityReaction kineticsBacteria (microorganisms)Waste Management and DisposalIn Situ Hybridization FluorescenceInhibitionPriority journalFree nitrous acidMicroscopyNitrous acidSewagebiologyFluorescence in situ hybridizationPH effectsGeneral MedicineSaturationRespirometryHydrogen-Ion ConcentrationInorganic acidsNitrite oxidizing bacteriaCalibrationOxidation-ReductionEnvironmental EngineeringInorganic chemistryBioreactorParameterizationBioengineeringActivated sludge reactorsArticleNumerical modelNitrous acid derivativeReaction rateParameter calibrationBatch experimentsNitrite-oxidizing bacteriaOxidationDietary NitrateNitritesTECNOLOGIA DEL MEDIO AMBIENTEExperimental studyBacteriaConcentration (process)Renewable Energy Sustainability and the EnvironmentBacteriologyNitrobacterOxidation reductionNitrogen removalConcentration (composition)biology.organism_classificationInorganic acidsMicrobial activityKineticschemistryActivated sludgeNitrite oxidationHigh pH valueSwitch functionConcentration (parameters)Oxidation processEffect of pHProtein expressionSubstrateControlled studyWaste disposalBioresource Technology
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