Personal Research Database

Full Text: W\Was Man15, 641.pdf

Abstract: Sorption of Sr on bentonite was studied using the batch technique. Distribution coefficients (K_d) were determined as a function of contact time, pH, sorbent and sorbate concentration and temperature. The data were interpreted in terms of Freundlich, Langmuir and Dubinin-Radushkevich isotherms. Thermodynamic parameters for the sorption system were determined at three different temperatures. The positive value of the heat of sorption, H° = 30.62 kJ/mol at 298 K, shows that the sorption of strontium on bentonite is endothermic. The negative value of the free energy of sorption, G° = -10.69 kJ/mol at 298 K, shows the spontaneity of the reaction. G° becomes more negative with increasing temperature, which shows that the sorption process is more favorable at higher temperatures. The mean free energy for sorption, E similar to 9 kJ/mol, suggests that ion exchange is the predominant mode of sorption in the Sr concentration range studied, i.e. 0.01-0.3 mol/dm³. The presence of complementary cations depresses the sorption of strontium on bentonite in the order Ca²⁺>Mg²⁺>K⁺>Na⁺. Some organic complexing agents and natural ligands also affect the sorption of strontium. The desorption studies with ground water at low strontium loadings on bentonite show that about 90% of Sr is irreversibly sorbed on the bentonite. Copyright (C) 1996 Elsevier Science Ltd

Keywords: Aqueous-Solutions, Adsorption, Cesium, Ions

Mayer, A. and Rey, T. (1996), Innovative HSR process to transform waste incinerator slag into useful mineral additives. Waste Management, 16 (1-3), 27-33.

Full Text: W\Was Man16, 27.pdf

Abstract: The Holderbank Smelting Redox-Process (HSR), which is patented world-wide, was born as a conse-quence of the general need for the reuse of waste and reduction of tipping fees for landfilling. Holderbank Management and Consulting Ltd (HMC) together with the Montan University of Leoben have developed a process to transform slags from municipal waste incineration into mineral additives. Laboratory and semi-industrial tests show its suitability as a mineral additive and the heavy metal compounds in the slag are transferred into usable heavy metal alloys separated from the molten slag. Preliminary estimates of the production costs are comparable with the costs of landfilling in Switzerland. Involved in the industrialisation of the HSR process is Von Roll Environmental Engineering Division, Zurich (specialised in environmental techniques). Moreover, the project is financially supported by the public authorities of Switzerland, comprising the Swiss Federal Ministry of Environment and several cantons. The HSR pilot plant (start-up in June 1995) will remain in operation for 2 years collecting all the relevant data required for planning the first industrial plant which should be in operation in 1998 with a capacity of about 20,000 t.p.a. Copyright (C) 1996 Elsevier Science Ltd

Johnson, C.A., Kersten, M., Ziegler, F. and Moor, H.C. (1996), Leaching behaviour and solubility: Controlling solid phases of heavy metals in municipal solid waste incinerator ash. Waste Management, 16 (1-3), 129-134.

Full Text: W\Was Man16, 129.pdf

Abstract: This paper highlights the uses and limitations of thermodynamic calculations in the planning of leach tests in the laboratory or for research in the field. Heavy metal solubility has been studied in leachate from Landfill Lostorf, AG, Switzerland. Also, the influence of pH on the solubility of Cu, Pb, Cd and Zn has been determined in the laboratory. The results have been compared with the maximum allowable heavy metal concentrations in equilibrium with the appropriate (hydr)oxides and carbonates. Copper is supersaturated with respect to Cu(OH)₂ in both laboratory and field studies. Complexation with organic ligands is a probable explanation for this observation. Both Zn and Pb are undersaturated with respect to pure (hydr)oxides and carbonates, though agreement between calculations and measurements are close enough, that PbCO₃ could be controlling the solubility in the laboratory experiments. The markedly lower concentrations of Pb in the field in comparison with the laboratory data could be explained by the affinity for Pb to bind to solids and the higher solid: solution ratio in field conditions. The solubility of Cd could be controlled by the formation of CdCO₃. The relatively high concentrations of Mo (up to 10^-5 M) in the landfill leachate could be limited by the precipitation of CaMoO₄. Copyright (C) 1996 Elsevier Science Ltd

Uchida, T., Itoh, I. and Harada, K. (1996), Immobilization of heavy metals contained in incinerator fly ash by application of soluble phosphate: Treatment and disposal cost reduction by combined use of ‘high specific surface area lime’, Waste Management, 16 (5-6), 475-481.

Full Text: W\Was Man16, 475.pdf

Abstract: Evaluation results of combined application of ‘High Specific Surface Area Lime’ and soluble phosphate as heavy metals immobilizing agent for fly ash intermediate treatment can help to reduce output of incinerator fly ash amount and total fly ash treatment and disposal costs. ‘High Specific Surface Area Lime’ injection rate to achieve same outlet HCL concentration will be reduced to about 1/2 of the conventional lime injection rate. As the residual lime content in the fly ash is reduced, the treatment costs by soluble phosphate can be remarkably reduced. (C) 1997 Elsevier Science Ltd.

Nakamura, K., Kinoshita, S. and Takatsuki, H. (1996), The origin and behavior of lead, cadmium and antimony in MSW incinerator. Waste Management, 16 (5-6), 509-517.

Full Text: W\Was Man16, 509.pdf

Abstract: The Amendment to the Waste Disposal and Public Cleansing Law in Japan has introduced new regulation of waste requiring strict management. In this regulation, the fly ash generated in the Municipal Solid Waste (MSW) incinerator process was designated as specially controlled solid waste because of relatively high concentrations of lead, and cadmium. Furthermore, antimony is a regulated constituent within the Basel Convention on the control of transboundary movements of hazardous wastes and their disposal and was designated a monitor item of environmental standards on water pollution. Thus, in order to understand where the problems lie, the behaviors of these heavy metals in the MSW incinerator was investigated. Also investigated were the kinds of products causing the fly ash to be contaminated. As a result, the amount of lead, cadmium and antimony in household waste was about 120, 3.5 and 7.6 g/T, respectively. The major origins of Pb, Cd and Sb from household waste are small sealed lead batteries, nickel-cadmium batteries and flame-proofed products such as curtains and plastic covers. By incineration treatment, these metals shifted to the fly ash (EP ash); the transfer ratio of Pb, Cd and Sb was about 33, 92 and 45%, respectively. The observed results indicated that the partitioning of metals in the MSW incinerator showed the influence of the vapor pressure of the elements and their compounds. Clearly, to produce precise estimates of this behavior, it will be necessary to determine not only the concentration of the elements in the waste but also the compounds used and the changes these would undergo in the furnace. Finally, several measures which will be helpful in solving these problems are introduced to discuss the future direction of environmentally-friendly social systems. (C) 1997 Elsevier Science Ltd.

Kida, A., Noma, Y. and Imada, T. (1996), Chemical speciation and leaching properties of elements in municipal incinerator ashes. Waste Management, 16 (5-6), 527-536.

Full Text: W\Was Man16, 527.pdf

Abstract: Different chemical properties of bottom ash and fly ash from municipal solid waste incinerators were compared based on the results of the five measuring techniques: (1) total contents and leaching amounts by regulatory leaching test in Japan; (2) leaching properties by pH-dependent leaching test; (3) modeling of pH-dependent leaching test using model compounds; (4) enriched chemical composition compared with bulk composition by an X-ray photoelectron spectrometer (XPS); (5) estimation of chemical states of elements by XPS analysis. The difference between bottom ash and EP ash was clearly found in element content, leaching behavior and release rate. The release rates of many elements in bottom ash were lower than in electrostatic precipitation (EP) ash even in an acidic condition of pH 3 as well as at the inherent pH of 12. Corresponding to the relatively complicated components in bottom ash, leaching patterns depending on pH were not simple. Comparison between the pH-dependent pattern of Ca in a sample and in model compounds resulted in the estimation of some Ca compounds in ash. The surface analysis by XPS showed results that Na, Cl, Zn, Pb and S were enriched in EP ash and Fe and Ti were rarely found in the surface of ash. Possible chemical states of Na, Ca, K, Cl and S were estimated by a new method of comparing binding energies of standard compounds and their mixtures. (C) 1997 Elsevier Science Ltd.

Kaneko, H. (1996), Evaluation of municipal waste incinerator fly ash toxicity and the role of cadmium by two aquatic toxicity tests. Waste Management, 16 (5-6), 555-559.

Full Text: W\Was Man16, 555.pdf

Abstract: Fly ash from a municipal solid waste incinerator in Japan is regulated under the hazardous waste regulation ‘Waste under Special Control’, according to the Amendment of the Waste Disposal and Public Cleansing Law, because it contains high concentrations of heavy metals which are available for leaching. To evaluate the toxicity of fly ash, a fly ash leachate was prepared according to the Japanese standard leaching procedure. The chemical analysis of the leachate showed that possibly one of the most toxic substances was cadmium. The toxicity of the leachate and the cadmium was determined by algal assay and a Daphnia acute toxicity test. The results showed that the leachate was about seven times more toxic to the growth of algae and 20 to 30 times more toxic to the survival of Daphnia than expected from its cadmium concentration. The toxicity interaction between cadmium and the other constituents in the leachate was also examined. The toxicity of cadmium showed an additive effect with the other constituents in the leachate in algal assay. In the Daphnia test, however, cadmium showed an antagonistic effect. (C) 1997 Elsevier Science Ltd.

Dutré, V. and Vandecasteele, C. (1996), An evaluation of the solidification/stabilisation of industrial arsenic containing waste using extraction and semi-dynamic leach tests. Waste Management, 16 (7), 625-631.

Full Text: W\Was Man16, 625.pdf

Abstract: Solidification/stabilisation of an industrial waste material containing large amounts of arsenic, as As₂O₃ (32wt%), was studied. The waste was treated using solidification/stabilisation (S/S) with cement (Ecobind50), lime and blast-furnace slags (Betogrid) in order to reduce the leachability of arsenic. In order to optimize the procedure for S/S, 10 different S/S samples, differing in amount and combination of the binder materials were prepared. On these samples, extraction tests were performed, showing that the arsenic concentration in the leachate is correlated with the pH and the calcium concentration due to the formation of slightly soluble CaHAsO₃. A semi-dynamic leach test was performed in order to obtain quantitative information on the long term leachability of the contaminants (As, Sb, Pb) from monolithic S/S samples. A linear relationship between the cumulative fractions released and the square root of the leach time was observed, indicating that diffusion is the release mechanism. From the diffusion coefficient, the influence of the binder materials on the leachability of the contaminants could be deduced. All the elements considered have a low mobility in all samples. Ca has the highest mobility followed by As and Sb, whereas Pb has the lowest mobility. It appeared that increasing the amount of calcium in the S/S samples lowers the leachability of arsenic, addition of lime being more effective than addition of cement. This conclusion is in good qualitative agreement with the extraction tests. (C) 1997 Elsevier Science Ltd.

Keywords: Behavior

Derie, R. (1996), A new way to stabilize fly ash from municipal incinerators. Waste Management, 16 (8), 711-716.

Full Text: W\Was Man16, 711.pdf

Abstract: Heavy metals and toxic chlorinated organics, added to very low grain-size distributions, make fly ashes from municipal incinerators a very hazardous waste. For their disposal, the present general trend is, not only to stabilize chemically the ashes, i.e. to reduce the leachability of the toxic substances, but also to stabilize them mechanically, i.e. to convert them into massive, resistant, and unleachable solids. This paper describes various stabilization methods used on representative European fly ash samples, which led to the development of a new stabilization technique taking place in four stages: elimination of the alkali chlorides by dissolution; addition of a moderate quantity of phosphoric acid; calcination; and solidification with Portland clinker or cement. The principal advantages of the process are as follows: the polychlorodibenzodioxins-polychlorodibenzofurans are destroyed, the reactivity of the heavy metals is reduced drastically, the final solids have satisfactory mechanical properties, and the increase in weight of the waste to be disposed of does not exceed one fourth. Comparative results of TCLP extraction tests are presented. (C) 1997 Elsevier Science Ltd.

Baltpurvins, K.A., Burns, R.C. and Lawrance, G.A. (1996), Heavy metals in wastewater: Modelling the hydroxide precipitation of copper(II) from wastewater using lime as the precipitant. Waste Management, 16 (8), 717-725.

Full Text: W\Was Man16, 717.pdf

Abstract: The effect of effluent composition (Cl^-, SO₄^2- or CO₃^2-) On the efficiency of the hydroxide precipitation of Cu(II) modelling lime (CaO) as the precipitant has been predicted using the solubility domain approach and has been experimentally validated. Solubility domains were based on the phases that were found to be solubility-limiting for systems representing potential effluent chemical composition limits. The generated solubility domains generally encompassed the experimentally observed solubilities, thereby providing effluent treatment quality assurance ranges for the hydroxide precipitation process. The presence of gypsum (CaSO₄.2H₂O) and calcite (CaCO₃) as secondary precipitates had little effect on the observed residual Cu(II) solubilities, with Cu(II) mobility being governed by the least-soluble kinetically precipitated (rather than thermodynamically favoured) phase in the system under study. (C) 1997 Elsevier Science Ltd.

Keywords: Paratacamite, Stabilities, Atacamite, Minerals, Sorption, Calcite, Water

Stucki, S. and Jakob, A. (1997), Thermal treatment of incinerator fly ash: Factors influencing the evaporation of ZnCl₂. Waste Management, 17 (4), 231-236.

Full Text: W\Was Man17, 231.pdf

Abstract: The efficiency of separation of Zn compounds from incinerator fly ash by evaporation at temperatures up to 1000°C depends on a number of factors and competing reactions. Model experiments with ZnCl₂ and a number of oxide matrices of defined composition (silica, alumina, a silica-alumina-calcia glass, and heat treated fly ash) in moist air were carried out in order to identify the chemical reactions involved and to investigate the relative importance of temperature, ZnCl₂ concentration, surface area and composition of the matrix oxide. Thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD) were used as experimental techniques. The hydrolysis and subsequent immobilisation of ZnO in the matrix oxide dominates the process at low temperatures and low ZnCl₂ concentrations, At high ZnCl₂ concentrations evaporation becomes more dominant, The Zn evaporation is governed by the vapour pressure of ZnCl₂ and limited by mass transfer to the purging gas stream. The development of new technologies for improved separation of Zn (and other heavy metals) from fly ash should focus on improving the mass transfer from particle grain to gas phase and avoid long residence times at temperatures below 600°C, (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Heavy-Metals

Wang, S. and Viraraghavan, T. (1997), Wastewater sludge conditioning by fly ash. Waste Management, 17 (7), 443-450.

Full Text: W\Was Man17, 443.pdf

Abstract: Conditioning wastewater sludge from the City of Regina Wastewater Treatment Plant by fly ash from Boundary Dam Power Station, Saskatchewan, Canada, was studied. Toxicity characteristic leaching procedure (TCLP), equilibrium leach test (ELT), and long-term leaching test (LTLT) were used to investigate the leachability of heavy metals. Results from these leaching tests indicated that, on the basis of concentrations of microorganisms and heavy metals (Cd, Cr, Cu, Ni and Zn), the sludge produced at the Regina Wastewater Treatment Plant conditioned by the locally available fly ash can be disposed of in landfills and used as a soil conditioner for land application. Sorption, and silicate and hydroxide precipitations were considered to be the three important mechanisms in fixation of heavy metals. High pH conditions were considered to be the predominant mechanism in killing microorganisms.

Keywords: Soil Microbial Activity

Ramakrishna, K.R. and Viraraghavan, T. (1997), Use of slag for dye removal. Waste Management, 17 (8), 483-488.

Full Text: W\Was Man17, 483.pdf

Abstract: Adsorption techniques employing activated carbon have been found to be reasonably effective in the removal of some of the ionic impurities in water. However, economic considerations may require the use of inexpensive sorbents which are either naturally available or available as waste products from manufacturing processes. Slag is one such waste product obtained during the manufacture of steel, and the present study investigates dye removal characteristics of slag from colored waters. Aqueous solutions prepared from commercial grade acid, basic, and disperse dyes were used in this study, and batch pH, kinetic, and isotherm studies were undertaken on a laboratory scale. The data were evaluated for applicability to the Langmuir, Freundlich, and BET isotherm models, and the removal capacity of slag was compared with that of granular activated carbon. Results indicated approximately 94% removal of the disperse dye by slag, compared with a removal of approximately 49% achieved by activated carbon. Removal of acid dyes (dyes containing anionic groups) was reasonably good (approximately 47 and 74%), though not as good as obtained using activated carbon (approximately 100%). Column studies were conducted with a disperse dye (nonionic, slightly soluble in water), and analysis of data showed a sorption capacity of 1.3 mg of disperse dye per gram of slag. However, effluent dye concentrations were found to be higher than the permissible levels for discharge to receiving waters.

Keywords: Adsorbents

Gupta, V.K., Srivastava, S.K., Mohan, D. and Sharma, S. (1997), Design parameters for fixed bed reactors of activated carbon developed from fertilizer waste for the removal of some heavy metal ions. Waste Management, 17 (8), 517-522.

Full Text: W\Was Man17, 517.pdf

Abstract: Activated carbon, developed from fertilizer waste, has been used for the removal of Hg²⁺, Cr⁶⁺, Pb²⁺, and Cu²⁺. Mass transfer kinetic approach has been successfully applied for the determination of various parameters necessary for designing a fixed-bed absorber. Parameters selected are the length of the (PAZ) primary adsorption zone (delta), total time involved for the establishment of primary adsorption zone (t_x), mass rate of flow to the absorber (F_m), time for primary adsorption zone to move down its length (t (delta)), amount of adsorbate adsorbed in PAZ from breakpoint to exhaustion (M_s), fractional capacity (f), time of initial formation of PAZ (t_f) and per cent saturation of column at break point. Chemical regeneration has been achieved with 1 M HNO₃.

Keywords: Slurry, Adsorption

Lo, I.M.C. and Yang, X.Y. (1998), Removal and redistribution of metals from contaminated soils by a sequential extraction method. Waste Management, 18 (1), 1-7.

Full Text: W\Was Man18, 1.pdf

Abstract: The fate of heavy metals in a contaminated soil is dependent on both the total amount of metals and the chemical forms in which they exist. A widely applied sequential extraction method was used to study the metal speciation in soils. Sequential extraction for metal-contaminated individual soil components and synthetic soils was performed. The experimental results show that the specific reagents were effective for the extraction of metals from the corresponding individual soil components; but the impact of non-corresponding reagents on other soil components was also significant. The chemical forms in which metals exist in the synthetic soils were complicated and different. Metals in soils might be released and redistributed during the sequential extraction process, but knowledge about this behavior and the extent of metal redistribution is ambiguous. (C) 1998 Elsevier Science Ltd. All rights reserved.

Keywords: Fractionation, Copper, Lead, Zinc

Lombardi, F., Mangialardi, T., Piga, L. and Sirini, P. (1998), Mechanical and leaching properties of cement solidified hospital solid waste incinerator fly ash. Waste Management, 18 (2), 99-106.

Full Text: W\Was Man18, 99.pdf

Abstract: A By ash coming from a hospital solid wastes incineration plant was solidified/stabilized in cementitious matrices. Owing to the high chloride, sulphate and alkali content and the low Si, Al and Fe values this By ash cannot be used in the formulation of blended cement. The objectives of solidification stabilization treatment were therefore to reduce the leachability of the heavy metals present in this material so as to permit its disposal in a sanitary landfill requiring only a low degree of environmental protection. The mechanical properties and leaching behaviour of solidified products were investigated. Fly ash and Portland Cement mixtures in ratios varying between 0.25 and 1.5 were tested for unconfined compressive strength after curing in tap water at 20°C. Leaching tests were performed both on By ash and solidified/stabilized products using an acetic acid standard leaching test and a modified version thereof (dynamic leaching test). (C) 1998 Elsevier Science Ltd. All rights reserved.

Clearfield, A., Bortun, A.I., Khainakov, S.A., Bortun, L.N., Strelko, V.V. and Khryaschevskii, V.N. (1998), Spherically granulated titanium phosphate as exchanger for toxic heavy metals. Waste Management, 18 (3), 203-210.

Full Text: W\Was Man18, 203.pdf

Abstract: Spherically granulated titanium phosphate of formula TiO1.25(OH)_(0.47)(H₂PO₄)_(0.77)(HPO₄)_(0.13) 2.3H₂O (TiP) was synthesized by a gel method and its Na⁺, Ca²⁺ and Mg²⁺ ion substituted forms were prepared. Ion exchange of some divalent metal cations (Pb²⁺, Cu²⁺, Ni²⁺, Mn²⁺, Cd²⁺) by TiP-Na, Tip-Mg and TiP-Ca was studied in batch and column conditions. It was found that the ion exchange performance of TiP depends on the ion form it is converted into and decreases in the order: Tip-Na > Tip-Mg > Tip-Ca. All TiP samples exhibit a high affinity for copper and especially lead ion and are able to remove these ions quantitatively in the presence of excess of Ca, Mg and Na ions. Thus spherically granulated titanium phosphate can be recommended for separation and selective recovery of some toxic divalent cations from industrial wastes and contaminated environmental streams. (C) 1998 Elsevier Science Ltd. All rights reserved.

Magdy, Y.H. and Daifullah, A.A.M. (1998), Adsorption of a basic dye from aqueous solutions onto sugar-industry-mud in two modes of operations. Waste Management,