Search results for " dissolved"
showing 10 items of 82 documents
Effects of Dissolved Complexation on REE Fate During Interactions between Volcanic Ash and Coexisting Fluids
2013
AbstractThis work analyzes REE behavior during the delivery of volcanic ash into a marine system and highlights the effects induced by dissolved carbonate and humate complexes on REE release. Kinetic experiments were carried out during a 6-month period using a batch method approach. Results show that the highest degree of REE leaching occurs during the early stage. Altered phases that crystallize induce REE sorption and dissolved complexation towards surface complexation, concurrent processes that are enhanced by Y/Ho, La/Yb, and Ce/Ce* changes, whereas dissolved humates and carbonates influence the dissolution rate of ash and the dissolved REE behavior.
An optical classification tool for global lake waters
2017
Shallow and deep lakes receive and recycle organic and inorganic substances from within the confines of these lakes, their watershed and beyond. Hence, a large range in absorption and scattering and extreme differences in optical variability can be found between and within global lakes. This poses a challenge for atmospheric correction and bio-optical algorithms applied to optical remote sensing for water quality monitoring applications. To optimize these applications for the wide variety of lake optical conditions, we adapted a spectral classification scheme based on the concept of optical water types. The optical water types were defined through a cluster analysis of in situ hyperspectral…
13C Differentiation between Dissolved and Solid Organic Carbon in Soils as Induced by Substitution of a Native Deciduous Forest by a Coniferous Forest
2006
International audience
Disintegration of Wastewater Activated Sludge (WAS) for Improved Biogas Production
2018
Due to rapid urbanization, the number of wastewater treatment plants (WWTP) has increased, and so has the associated waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas via fermentation processes. This review presents recent advances in the anaerobic digestion processes that have led to greater biogas production. Disintegration techniques for enhancing the fermentation of waste activated sludge can be apportioned into biological, physical and chemical means, which are included in this review; they were mainly compared and contrasted in terms of the ensuing biogas yield. It was found that ultrasonic- and microwave-assisted disintegrati…
Aerobic composting and anaerobic digestion of pulp and paper mill sludges
1997
The feasibility of aerobic vessel composting and anaerobic digestion for the treatment of pulp and paper mill sludges were studied. The composting studies made use of primary and secondary sludge from a de-inking and paper mill. In six parallely aerated 500 1 vessels with various carbon : nitrogen (C:N) -ratios, the most optimal performance was obtained with C:N -ratios of c. 22–35, while higher and lower ratios delayed the temperature increase. With the optimal ratios, the thermophilic stage was reached within 36 h, and the stage lasted for about seven days. In the scale-up study (18 m3 compost vessel), the thermophilic stage was reached within 24 h. An effective dehydratation of the mass …
Bleaching of color of kraft pulp mill effluents and natural organic matter in lakes
2002
In situ changes in the color of lake water and biologically treated kraft pulp mill effluents mixed in lake water were examined in three lakes. In 1.7 m3 enclosures, the color (400700 g Pt·m3) of the mixture of pulp mill effluent and lake water remained similar for 4 months in darkness, whereas exposure to solar radiation resulted in 1742% bleaching of color. During the summer stratification of a humic lake, the color (160 g Pt·m3) of hypolimnetic water remained similar to that found during spring turnover, but the color of epilimnion decreased 13%. The measured rates of photochemical bleaching of color by solar radiation could explain the decrease of epilimnetic color. Attenuation of …
Multiple origins of methane in fluids circulating in the Othrys ophiolite, central Greece
2018
The complex geology of Greece includes two important parallel running ophiolitic belts. The Othrys Massif in central Greece belongs to westernmost of them. In and around this wide ophiolite outcrop, some cold hyperalkaline and some hypothermal (T < 40°C) alkaline springs are present. Thirty water samples were collected at 17 different sites and both bubbling and dissolved gases were analysed for their chemical (He, Ne, H2, O2, N2, CH4, C2H6, CO2 and H2S) and isotope (He, δ13C-CO2, δ 13C-CH4, δ 2H-CH4) composition. All samples except one have H2S contents below detection limit (10 μmol/mol), whilst H2 (from <2 to 2500 μmol/mol), CO2 (up to 26,000 but generally below 1000 μmol/mol) and …
Isotope distribution of dissolved carbonate species in southeastern coastal aquifers of Sicily (Italy)
2007
Concentrations of major ions and the δ13C composition of dissolved inorganic carbon in groundwater and submarine groundwater discharges in the area between Siracusa and Ragusa provinces, southeastern Sicily, representing coastal carbonate aquifers, are presented and discussed. Most of groundwater analysed belongs to calcium bicarbonate type, in agreement with the geological nature of carbonate host rocks. Carbonate groundwater acquires, besides the dissolution of carbonate minerals, dissolved carbon (and the relative isotopic composition) from the atmosphere and from soil biological activity. In fact, δ13C values and total dissolved inorganic carbon contents show that both these sources con…
Automated water quality monitoring of humic lakes by using the optical properties of water
2016
Automated water quality monitoring (AWQM) is becoming increasingly common in lakes worldwide. The history of AWQM is relatively short and standard calibration procedures for the measured variables are largely yet to be established. The use of optical AWQM sensors, developed in oceanic environments, raises new questions on the diverse effects which humic compounds may have on the automated optical measurements in inlands waters. The focus of this thesis was to characterize the effects of coloured dissolved organic matter (CDOM) on optical in situ measurements of organic matter (OM) and chlorophyll (Chl) in lakes with varying humic content, and to use AWQM data as a part of traditional monito…
KOSMOS 2017 Peru Side Experiment: nutrients, phytoplankton abundances, enzyme rates, photophysiology
2022
This data was collected during an short-term incubation experiment in March 2017 that investigated the response of a surface plankton community to upwelling. This experiment was carried in the framework of the SFB754-funded KOSMOS mesocosm study that took place in La Punta, Callao, Peru between February-April 2017. A total of six different treatments were used to disentangle chemical and biological characteristics of deep water that influence surface plankton blooms: 2 different deep water sources with different nutrient concentrations; 3 treatments to distinguish the effects of inorganic nutrients, organic nutrients and deep water microbial populations. Measured variables include inorganic…