Factors affecting hazardous waste solidification/stabilization: a review.

The treatment of hazardous wastes using cement-based solidification–stabilization (S–S) is of increasing importance as an option for remediating contaminated sites. Indeed, among the various treatm...

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Solidification/Stabilization of Organic and Inorganic Contaminants using Portland Cement: A Literature Review

Durability and microstructure characteristics of alkali activated coal bottom ash geopolymer cement

Preparation of geopolymer from fluidized bed combustion bottom ash

This paper presents the physical, chemical and mechanical characteristics of sewage sludge ash (SSA), in order to compare its properties with the standard requirements for coal fly ash (FA). It also provides an evaluation of its environmental behaviour when used as a mineral admixture in cement-based materials. Results show that, compared with FA, SSA has a high amount of calcium and phosphorus but a relatively low fraction of silica. SSA is composed of irregular grains having a high specific surface area and thus leading to a high water demand. The high water absorption of SSA requires an increase of the water–binder ratio of mortars, or the use of a water-reducing admixture. The strength activity index (25% replacement of cement) reaches more than 90% after 28 days, showing a long-term positive effect, which might be related to the pozzolanic activity. The amount of leached elements of SSA mortars is slightly higher than for the reference mortar without residue, but it remains within the same order of m...

Use of sewage sludge ash as mineral admixture in mortars

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.

Stabilization/Solidification of Wastewater Treatment Sludge

The technology of fluidized-bed combustion (FBC) of coal generates byproducts that have a series of unique characteristics and potential uses in technological practice. In this study, the products of fluidized-bed combustion (FBC-P) of coal derived from Moravian heat stations, a.s. Zlin, Cinergy Global Resources, Czech Republic, were characterized. Particular attention was paid to determining the chemical composition of FBC-P, the content of polycyclic aromatic hydrocarbons (PAHs) and toxic metals in the water leachates of these FBC-P, the content of unburned carbon, the capability of FBC-P to solidify with water and form a solid matrix, and the method for discovering optimum mixing water content for FBC-P solidification. The results suggest that one of the qualitatively more important means of utilizing FBC-P could be their application during solidification/stabilization (S/S) of wastes, particularly wastewater treatment sludges.

Characterization of products from fluidized-bed combustion of coal.

A procedure for stabilization/solidification of loose waste from the manufacture of Ni and Cd electrodes, which represents a nonutilizable and noncombustible hazardous waste, has been worked out. The procedure comprises solidifying the waste by means of an anionic slow-setting aqueous-asphalt emulsion with subsequent formation of an asphalt coating on the surface of solidified waste by spraying with an anionic rapid-setting aqueous-asphalt emulsion. This asphalt coating represents a secondary barrier against leaching of pollutants into the environment. Results of leachability tests with water (Czech Republic regulations) as well as with acetic acid (toxicity characteristic leaching procedure test, EPA) are evidence of the successful stabilization of given waste. Values of determined leachability parameters of test specimens prepared from stabilized waste are very favorable and, in addition, virtually the same as those of blank test. This demonstrates, in a convincing manner, efficiency of the developed stabilization/solidification procedure. Results have also shown the toxicity characteristic leaching procedure test is indispensable for the assessment of toxic metals leachability. Performed tests have shown a marked drop in ecotoxicity from relatively high toxicity of untreated waste leachate to low toxicity of stabilized waste leachate.

Marek Sild

Papers

Stabilization/Solidification of Wastewater Treatment Sludge

Characterization of products from fluidized-bed combustion of coal.

Stabilization/Solidification of Noncombustible Industrial Waste by Asphalt Emulsions