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1

Microbial hydrogen sulfide elimination in a continuous biotrickling reactor by immobilized Thiobacillus thioparus

Tóth G., Lövitusz E., Nemestóthy N., Bélafi-Bakó K.

Environment Protection Engineering

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2017

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Vol. 43, nr 1

19--30

EN

Elimination of hydrogen sulfide from gaseous streams by biological treatments is a promising alternative procedure, among them biotrickling reactor seems a reliable and efficient system. To maximize the performance, strains should have high hydrogen sulfide elimination efficiency; excellent carriers should be selected where the microbes can be immobilized. Various carriers were used as the support medium for the immobilization of Thiobacillus thioparus and a continuous biotrickling reactor was constructed and operated for H2S elimination. It was found that such systems with Mavicell and Kaldnes supports are able to remove H2S from gas mixtures with high efficiency (95–100%), and the elimination capacity was calculated as a high as 30–40 g S/(m3·h).

2

Investigation of Hungarian torsion balance measurements by prediction

Tóth G., Völgyesi L.

Reports on Geodesy

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2005

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z. 2/73

277-284

EN

Torsion balance measurements in Hungary were checked by least-squares collocation. The methodology was the so-called "leave-one-out" prediction of horizontal gravity gradients. The method was succesfully tested on a selected subset of 700 torsion balance measurements and only three possible outliers has been detected. These results are promising in view of a planned new Hungarian geoid determination.

3

Modelling time variation of gravity gradients due to water level fluctuations

Tóth G., Völgyesi L., Cerovský I.

Reports on Geodesy

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2004

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nr 2/69

309--314

EN

The water level fluctuations of the Danube River in Budapest during the great flood in 2002 were recorded. The 3D model of the river bed allowed us to build an accurate polyhedral model of the time variation of mass changes of the flood. This mass density variation model made it possible to compute and compare time variations of various gravitational field functionals. Gravity and full gravitational gradient tensor changes were computed on a regular grid for the model area and these changes were compared with accuracies attainable for gravity measurements. This way we were able to evaluate which kind of gravitational field parameter is more suitable for detecting gravitational field variations due to near-site mass changes. Gravity changes were also compared with actual gravitational field measurements made during the flood with two LCR gravimeters. We studied also the possibility of predicting gravity changes from certain combinations of measured gravity gradients where no mass variation model is available. This latter technique may be relevant in the future to support absolute gravity measurements by detecting the effect of local gravitational field changes through repeated gravity gradient measurements.

4

Comparison of interpolation and collocation techniques using torsion balance data

Tóth G., Völgyesi L.

Reports on Geodesy

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2002

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z. 1/61

171-182

EN

First the relewant theory of the interpolation and collocation methods, both used here for the recovery of deflections of the vertical and geoid heights from torsion balance data is discussed. We have selected a mostly flat area in Hungary where all kind of torsion balance measurements are available at 249 points. There were 3 astrogeodetic points providing initial data for the interpolation, and there were geoid heights at 10 checkpoints interpolated from an independent gravimetric geoid solution. The size of our test area is about 800 km sq.m. and the average site distance of torsion balance data is 1.5-2 km. The interpolation method provided a least squares solution for deflections of the vertical and geoid heights at all points of the test network. By collocation two independent solutions were computed from W(zx), W(zy) and W(yy)-W(xx), 2W(xy) gradients for all the above, using astrogeodetic data to achieve a complete agreement at these site with the interpolation method. These two solutions agreed at the cm level for geoid heights. The standard deviation of geoid height differences at checkpoints were about +-1-3 cm. The W(yy)-W(xx) , 2W(xy) combination (i.e. pure horizontal gradients) yielded better results since the maximum geoid height difference was only 3.6 cm. The differences in the deflection components were generally below 1", slightly better for the (pi) component. The above results confirm the fact that torsion balance measurements give good possibility to compute very precise local geoid heights at least for flat areas.