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881.
D. K. Uan I. T. Yeom P. Arulazhagan J. Rajesh Banu 《International Journal of Environmental Science and Technology》2013,10(3):495-502
Excess sludge disposal is one of the serious challenges in biological wastewater treatment. Reduction of sludge production would be an ideal way to solve sludge-associated problems rather than the post-treatment of the sludge produced. In this study, a new wastewater treatment process combining anaerobic/anoxic/oxic system with thermochemical sludge pretreatment was tested in a laboratory scale experiment. In this study, the effects of the sludge pretreatment on the excess sludge production in anaerobic/anoxic/oxic were investigated. The system was operated in two Runs (1 and 2). In Run 1, the system was operated as a reference and in Run 2, a part of the mixed liquid was pretreated thermochemically and was returned to the bioreactor. The average solubilization efficiency of pretreated sludge was found to be about 35 % during the study period of 220 days. Sludge production rate in Run 2 was less than that in Run 1 by about 52 %. Total phosphorous was removed by enhanced biological phosphorous removal with the removal efficiency of 83–87 % and 81–83 % for Run 1 and Run 2, respectively. Total nitrogen removal in Run 2 (79–82 %) was slightly higher than that in Run 1 (68–75 %). The mixed liquor suspended solids/mixed liquor volatile suspended solids ratio was identical after both runs in the range 78–83 %. The effluent water qualities were not significantly affected when operated with thermochemical pretreatment at pH 11 and 60 °C for 3 h during 7 months. From the present study it is concluded that thermochemical sludge pretreatment of anaerobic/anoxic/oxic process plays an important role in reduction of sludge production. 相似文献
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Cordieritites and highly peraluminous granites within the ElPilón granite complex, Sierras Pampeanas, Argentina,were emplaced during a medium-P, high-T metamorphic event duringthe initial decompression of a Cambrian orogen along the southwesternmargin of Gondwana. Very fresh orbicular and massive cordierititebodies with up to 90% cordieritite are genetically associatedwith a cordierite monzogranite pluton and a larger body of porphyriticgranodiorite. The petrogenesis of this association has beenstudied using petrographical, mineralogical, thermobarometric,geochemical, geochronological and isotope methods. The graniticmagmas were formed by anatexis of mid-crustal metamorphic rocksformed earlier in the Pampean orogeny. The cordieritites appearat the top of feeder conduits that connected the source regionlocated at 相似文献
885.
Mercury from mineral deposits and potential environmental impact 总被引:6,自引:0,他引:6
James J. Rytuba 《Environmental Geology》2003,43(3):326-338
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This paper reports REE data on resin-asphaltene components of oil from six oil-gas-bearing provinces and on bitumoids from
inferred oil-source rocks (domanikites and bazhenites). It was shown that, regardless of geological-tectonic structure of
the regions, oil composition, depth of reservoirs, and host lithologies, oil exhibits significant REE fractionation, and,
unlike bitumoids, positive Eu anomaly. The (Eu/Sm)n ratio increases from asphaltenes to resins and further to oils. Based on REE distribution in oil, source rocks, and bitumoids,
it was concluded that deep-seated fluids were one of the possible sources that defined the trace element composition of oil. 相似文献
889.
I. Yu. Melekestseva V. A. Kotlyarov P. V. Khvorov V. N. Ivanov V. E. Beltenev I. G. Dobretsova 《Geology of Ore Deposits》2010,52(8):800-810
The porous fine-grained to microcrystalline copper-zinc ore of the Semenov-2 hydrothermal field, a site in the Semenov hydrothermal
cluster discovered in 2007 (13°31′N, MAR), is anomalously enriched in Au (22–188 ppm) and Ag (127–1787 ppm). Chalcopyrite,
isocubanite, würtzite, and opal are major minerals; sphalerite, marcasite, pyrite, and covellite are auxiliary; and galena,
pyrrhotite, native gold, silver telluride, barite, and aragonite are sporadic. Gold containing 0.31 to 23.07 wt % Ag occurs
as up to 9-μm-sized subhedral, dendritelike, and elongated grains mostly hosted in opal and less frequently in sphalerite
and in pores within isocubanite-chalcopyrite aggregate. An elongated grain (2 × 4 μm in size) of the Ag-Te phase was found
in a pore. So far only basalts have been dredged from the Semenov-2 field, but anomalous gold and silver concentrations suggest
the influence of ultramafic rocks; the latter were found 1.5 km westward, in the Semenov-1 hydrothermal field. Mineral assemblage
and morphology of gold particles indicate its primary origin in contrast to the hydrothermal fields hosted in basalts, where
gold is a product of remobilization. Zonal gold grains, found on oceanic floor for the first time, are characterized by low
Ag content in the cores and high Ag content in the outer rims, reflecting variation in formation conditions. 相似文献
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