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M. Vondruska

Bio: M. Vondruska is an academic researcher. The author has contributed to research in topics: Hexavalent chromium & Chromium. The author has an hindex of 1, co-authored 1 publications receiving 11 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, a laboratory procedure was developed and verified for neutralizing highly toxic ash from incinerators that contain extreme quantities of soluble hexavalent chromium by means of stabilization/solidification with an asphalt binder.
Abstract: A laboratory procedure was developed and verified for neutralizing highly toxic ash from incinerators that contain extreme quantities of soluble hexavalent chromium by means of stabilization/solidification with an asphalt binder. Relevant parameters of stabilizate leachability approach zero values, so that prepared stabilizate forms an inert, environmentally stable material. The volume of processed waste is noticeably reduced during stabilization. The mechanism of stabilization consists in creating a perfect impermeable barrier against leaching with water. Using simulated waste with added trivalent chromium salt, the versatility of the developed procedure was proven, producing perfect stabilization of both anionic and cationic forms of chromium.

11 citations


Cited by
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TL;DR: The effect of different waste stream such as heavy metals bearing sludge, filter cake, fly ash, and slag on the properties of cement and other binders is summarized.

385 citations

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TL;DR: Leachate parameters exhibited very low values and favorable results of ecotoxicological tests indicate high efficiency of the developed procedure for galvanic sludge disposal.

48 citations

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TL;DR: In this article, the authors tried to find some suitable solutions to disposal of this arsenic-bearing sludge and found that in the preparation of briquette, cement-sand mortar and concrete, mixing up to 10, 18 and 40% of arsenic-laden sludge by volume, respectively with the other common ingredients did not produce a TCLP leachate beyond its permissible direct inland water discharge standards of 0.2 g/m3 as stipulated by the Ministry of Environment & Forest, Government of India.
Abstract: When arsenic is co-precipitated with iron hydroxide in an arsenic-removal water plant, a large quantity of sludge is generated which contains a good amount (an average of 6.1 kg As/m3 of sludge) of arsenic. The present paper attempts to find some suitable solutions to disposal of this arsenic-bearing sludge. As a safe means of disposal, stabilization processes such as briquette production, cement mortar and concrete making have been attempted in the present investigation. It has been found that in the preparation of briquette, cement–sand mortar and concrete, mixing up to 10, 18 and 40% of arsenic-bearing sludge by volume, respectively with the other common ingredients did not produce a TCLP leachate beyond its permissible direct inland water discharge standards of 0.2 g/m3 as stipulated by the Ministry of Environment & Forest, Government of India. Also, it was noted that 25% (by volume) of cement could be replaced by fly ash to stabilize arsenic-laden sludge to the tune of 11% by volume of cement–sand (1 : 3) mortar.

29 citations

Journal ArticleDOI
TL;DR: Comparative experimental investigations of pyrolysis and incineration revealed that incineration could be a potential treatment and disposal option, in developing countries like India, for chrome-tanned leather solid wastes from tanneries, for producing heat energy and the residue with potential utilization viability in another industry paving a way towards circular economy.
Abstract: Chrome-tanned leather solid wastes (leather finished trimmings (LFT) and chrome shavings (CS)) from tanneries were studied using pyrolysis and incineration. Detailed characterization of CS and LFT indicated higher calorific value of 15.77 MJ/kg and 19.97 MJ/kg respectively, which makes it suitable for thermal treatment. Thermal Gravimetric Analysis (TGA) of CS and LFT recorded a weight loss of 79.82% and 68.22% at 800 °C respectively. Energy-dispersive X-ray spectroscopy and scanning electron microscopy analysis for CS and LFT were also carried out. Pyrolysis of CS and LFT was carried out using a fixed bed–type pyrolysis unit at a temperature of 500 ± 10 °C for a reaction time of 30 min and three different by-products (bio-oil, biochar and pyrolytic gas) were obtained as a result of pyrolysis. From pyrolysis process, higher bio-oil yields of 52 wt.% and 49 wt.% from LFT and CS with calorific value of 28.0 and 27.8 MJ/kg respectively were obtained. The calorific values of the biochar obtained from LFT and CS were found to be 20.5 and 23.0 MJ/kg respectively. Incineration was carried out in the existing incineration facility of 150 kg/h capacity at a temperature of 1200 °C. The results of incineration process showed a higher weight reduction (93.0 wt.%) and higher concentration of gaseous emissions, revealing the need for off-gas treatment. Further, FT-IR spectra of residual ash from the incineration process revealed the occurrence of oxidation of trivalent chromium to its hexavalent form, which could be a potential raw material in the metallurgical/chemical industry for the synthesis of sodium chromate or ferrochrome alloy. Comparative experimental investigations of pyrolysis and incineration revealed that incineration could be a potential treatment and disposal option, in developing countries like India, for chrome-tanned leather solid wastes from tanneries, for producing heat energy and the residue with potential utilization viability in another industry paving a way towards circular economy.

24 citations

Journal ArticleDOI
TL;DR: In this article, an effective procedure for stabilization/solidification of industrial wastewater treatment sludge has been developed and verified, which consists of economically advantageous sludge solidification by fluidized bed combustion ash with an addition of highly porous carbon black as an adsorption additive, and subsequent creation of an asphalt coating on the surface of the solidified sludge by means of aqueous asphalt emulsion.
Abstract: An effective procedure for stabilization/solidification of industrial wastewater treatment sludge has been developed and verified. The procedure consists of economically advantageous sludge solidification by fluidized bed combustion ash with an addition of highly porous carbon black as an adsorption additive, and subsequent creation of an asphalt coating on the surface of the solidified sludge by means of aqueous asphalt emulsion. The carbon black addition enables the reduction of binder dosage needed for solidification of the sludge and simultaneously reduces the leachability of organic compounds. The creation of an asphalt coating effectively prevents leaching of all pollutants observed. The method also reduces the infectiousness of the stabilized/solidified sludge.

19 citations