Solid Waste Forms Research Articles

Immobilization of radioactive borate liquid waste using natural diatomite

In this article, influence of diatomite as a natural adsorbent in immobilization of radioactive borate liquid waste in the cement-diatomite matrix was investigated. Cylindrical concrete mixtures were prepared with different amounts of diatomite additives at three different w/c values. Mechanical strength tests were carried out to determine the uniaxial compressive strength of the samples. A new dynamic column type leaching tests were applied to the solidified waste forms, and leach rates of 137Cs and 60Co were determined according to different diatomite additives. The experimental results indicated that the increasing of the diatomite additive amounts resulted high isolation performance of the solidified waste form. However, the results revealed that mechanical strength decreases with increasing borate diatomite amount. Results show that 9% amount of natural diatomite is effective as an admixture of the cementation process for achieving long-term stability of solidified borate waste. Optimum strength and leach values were determined as 11.5 MPa with leaching rates of 7.5 × 10−4 and 3.2 × 10−5 cm/d for 137Cs and 60Co, respectively.

The impact of the local dairy cattle farm toward the river water quality in Gunungpati Subdistrict Central Java

People’s awareness on the living environment nowadays is not yet comes up to the dairy-farmer community. In fact, the dairy-farm subsector contributes load pollution in the form of waste. The waste that is produced by a dairy-farm can be in the form of solid waste and liquid waste. There is still no cultivation effort toward the wastes in a traditional dairy-farmyet, thus most of the wastes are disposed to the closest river, so that in the surrounding dairy farm area is frequently found pollution toward the water quality. The aim of this study is to identify the effect of environment pollution that is caused by local dairy farm in Gunungpati Sub-district, especially toward the river water and residents’ well. The result of this study in Nangkasawit Village before and after the dairy farm was build was still under the quality standard for the third rate water quality. In Plalangan Village, the water quality was also under the quality standard, except for COD concentration. In the Sumurejo Village there was an upturn tendency on the observation value, but the water quality was under the quality standard, except for Fe concentration. Based on the Biodiversity Index before and after the dairy farm was established in Nangkasawit, Plalangan, and Sumurejo were 2.22, 1.49, 2.11, 1.90, 1.78, and 1.88, respectively. It means that Nangkasawit showed no pollution before the dairy farm was established, while there was a medium pollution after the dairy farm establishment. In Plalangan, the water was clear, but it was light polluted after the dairy farm was established. In Sumurejo, before and after the dairy farm establishment the water was light category pollution.

Investigation of the swelling behavior of cationic exchange resins saturated with Na+ ions in a C3S paste

Ion exchange resins (IERs) are widely used by the nuclear industry to decontaminate radioactive effluents. Spent products are usually encapsulated in cementitious materials. However, the solidified waste form can exhibit strong expansion, possibly leading to cracking, if the appropriate binder is not used. In this work, the interactions between cationic resins in the Na+ form and tricalcium silicate are investigated during the early stages of hydration in order to gain a better understanding of the expansion process. It is shown that the IERs exhibit a transient swelling of small magnitude due to the decrease in the osmotic pressure of the external solution. This expansion, which occurs just after setting, is sufficient to damage the material which is poorly consolidated for several reasons: low degree of hydration, precipitation of poorly cohesive sodium-bearing C–S–H, and very heterogeneous microstructure with zones of high porosity.

MICROBIAL LEACHING OF CHROMIUM FROM SOLIDIFIED WASTE FORMS – A KINETIC STUDY

In this study, Thiobacillus thiooxidans (T. thiooxidans) was used to study the microbial stability / degradation of cement-based waste forms. The waste forms contained a chromium salt (CrCl3·6H2O), cement and other additives viz., lime and gypsum in two different proportions. The experimental samples of all the simulated waste forms showed evidence of microbial growth as indicated by substantial increase in sulfate. Chromium leached from the waste forms was found to be lowest in cement – lime solidified waste forms (0.061 mg·l-1) and highest in cement gypsum waste forms (0.22 mg·l-1) after 30 days of exposure. These values were lower than the toxicity characteristic leaching procedure (TCLP), regulatory limit (5 mg·l-1). Model equations based on two shrinking core models (acid dissolution and bulk diffusion model), were used to analyze the kinetics of microbial degradation of cement based waste forms. The bulk diffusion model was observed to fit the data better than the acid dissolution model, as indicated by good correlation coefficients

The ISSMGE Kerry Rowe Lecture: The role of diffusion in environmental geotechnics

Diffusion of contaminants can play a significant if not dominant role in many applications encountered within the field of environmental geotechnics. The objective of this paper is to provide an overview of the important role diffusion plays in such applications. The presentation proceeds from a historical perspective, beginning with the recognition in the late 1970s to early 1980s that diffusion may be an important process in assessing contaminant migration through low-permeability barriers in waste containment applications. Data from the literature and simplified model simulations are used to illustrate under what conditions diffusion is important, and the significance of diffusion is illustrated with respect to different barrier components and types of barriers used in waste containment applications. The barriers considered include natural clays, compacted clay liners, geomembranes, geosynthetic clay liners, composite liners, vertical cutoff walls, subaqueous caps for contaminated sediments, and highly compacted bentonite buffers for high-level radioactive waste containment. The significance of semi-permeable membrane behavior on liquid-phase diffusion through bentonite-based barriers also is highlighted. The potential importance of matrix diffusion as an attenuation mechanism for contaminant transport is illustrated, and the roles of both liquid-phase and gas-phase diffusion under unsaturated conditions are discussed. Finally, the role of diffusion in terms of remediation applications is illustrated via an example analysis illustrating the impact of reverse matrix or back diffusion on the effectiveness of pump-and-treat remediation, as well as via a summary of several diffusion-based models commonly used to describe the leaching of contaminants from a variety of stabilized–solidified waste forms.

Decontamination and solidification of liquid radioactive waste using natural zeolite

This study is based on evaluation of solidification methods for low-level radioactive liquid using natural zeolite. In classical method, LLW is decontaminated using zeolite and after the process spent zeolite becomes radioactive waste. After decontamination process, zeolite waste is solidified using cement, sand and water. In this method; liquid radioactive waste was used instead of water, natural zeolite was used instead of sand/aggregate and cement was used for binding the mixture in solidification process. In this study, leaching properties and strength of the solidified waste form were investigated for both techniques. Effect of temperature on the radionuclide adsorption of the zeolite was determined to optimize the waste solution temperature for the plant scale operations. In addition, the effect of pH on the radionuclide uptake of the zeolite was determined to optimize the waste solution’s pH for the plant scale operations. The advantages of this method used for the processing of LLW were discussed in this paper.

Peak Waste? The Other Side of the Industrial Cycle

The modern industrial cycle is mainly based on non-renewable mineral resources extracted from the Earth’s crust. After being processed and transformed into commodities, the products of mining become manufactured products which go through the economic system and are then discarded in the form of gaseous, liquid or solid waste. Eventually, the mass of the output in the form of waste must balance the input in the form of minerals. A large number of model studies have been performed on the first phase of the cycle—the production of mineral commodities—often with a specific interest in fossil fuels, with the objective of determining the future prospects of production. However, very few model studies of this kind have been performed about the future trends of waste generation. In this paper, we examine models of the industrial cycle compared to historical trends in municipal solid waste generation for different regions of the world. We show that waste generation in developed countries goes in parallel with the trends of industrial production and that several regions are showing a declining trend which may be interpreted in terms of “peaking” just as it is often done for the production of fossil fuels. Therefore, the “waste problem” in terms of increasing amounts of waste to be processed and disposed may not be so urgent as it is commonly perceived.

Assessing E-Waste Management within the Mangaung Metropolitan Municipality , South Africa

With rapid advancements in technology the evolution and demand for electronic/electric devices have drastically increased. The exponential increase in the use of technology, to meet the needs of the fast paced information era, has led to electronic and electrical devices being discarded, or disposed of, at a quicker rate than in the past. This has resulted in the fastest growing form of solid waste, called e-waste. E-waste is categorized as hazardous waste and can be harmful to the environment and health if not disposed of in a responsible manner. The emphasis is therefore to look at alternatives, such as reusing, refurbishing, or recycling, in order to minimise the disposal of this toxic waste form into landfill sites. This exploratory study concentrated on Mangaung Metropolitan Municipality (MMM) South Africa and revealed that e-waste management practices are a concern in this metropolitan area. The level of e-waste awareness and practices show that initiatives in MMM need to be expedited in order to adhere to e-waste best practices that have been implemented nationally and internationally.

Ba(OH)2 – blast furnace slag composite binders for encapsulation of sulphate bearing nuclear waste

The present study investigated the feasibility of the immobilisation of sulphate bearing radioactive wastes in blast furnace slag (BFS) based binders. BaSO4–BFS composites were produced via two methods using Na2SO4 as a waste simulant, along with Ba(OH)2 to promote precipitation of BaSO4 in an insoluble sulphate form and the consequent activation of the BFS. BaSO4 was effectively formed by both methods, and solid wasteforms were successfully produced. Although both methods produced BaSO4 embedded in the cement-like composites, different reaction products including ettringite and witherite were produced, depending on the order Ba(OH)2 was mixed with the system. These results show that the immobilisation of soluble sulphate-bearing aqueous wastes is achievable in Na2SO4–Ba(OH)2–BFS composites.

Influence of fracture networks on radionuclide transport from solidified waste forms

Analysis of the effect of fractures in porous media on fluid flow and mass transport is of great interest in many fields including geotechnical, petroleum, hydrogeology and waste management. This paper presents sensitivity analyses examining the effect of various hypothetical fracture networks on the performance of a planned near surface disposal facility in terms of radionuclide transport behaviour. As it is impossible to predict the initiation and evolution of fracture networks and their characteristics in concrete structures over time scales of interest, several fracture networks have been postulated to test the sensitivity of radionuclide release from a disposal facility. Fluid flow through concrete matrix and fracture networks are modelled via Darcy's law. A single species radionuclide transport equation is employed for both matrix and fracture networks, which include the processes advection, diffusion, dispersion, sorption/desorption and radioactive decay. The sensitivity study evaluates variations in fracture network configuration and fracture width together with different sorption/desorption characteristics of radionuclides in a cement matrix, radioactive decay constants and matrix dispersivity. The effect of the fractures is illustrated via radionuclide breakthrough curves, magnitude and time of peak mass flux, cumulative mass flux and concentration profiles. For the investigated system, radionuclide properties and the imposed water flow boundary conditions, results demonstrate that: (i) magnitude of peak radionuclide fluxes is less sensitive to the fracture network geometry, (ii) timing of the peak radionuclide fluxes is possibly sensitive to the fracture networks, (iii) a uniform flow model represents a limiting case of a porous medium with large number of fine fractures, (iv) the effect of fracture width on the radionuclide flux depends on the ratio of fracture to matrix conductivity and is less sensitive if the ratio is large and the width is higher than a certain critical size, and (v) increased dispersivity in fractured media influences the transport behaviour differently compared to non-fractured media; in particular, the behaviour depends on the nature of fracture network.

Biological responses of agricultural soils to fly-ash amendment.

The volume of solid waste produced in the world is increasing annually, and disposing of such wastes is a growing problem. Fly ash (FA) is a form of solid waste that is derived from the combustion of coal. Research has shown that fly ash may be disposed of by using it to amend agricultural soils. This review addresses the feasibility of amending agricultural field soils with fly ash for the purpose of improvings oil health and enhancing the production of agricultural crops. The current annual production of major coal combustion residues (CCRs) is estimated to be -600 million worldwide, of which about 500 million t (70-80%) is FA (Ahmaruzzaman 2010). More than 112 million t of FA is generated annually in India alone, and projections show that the production (including both FA and bottom ash) may exceed 170 million t per annum by 2015 (Pandey et al. 2009; Pandey and Singh 20 I 0). Managing this industrial by-product is a big challenge, because more is produced each year, and disposal poses a growing environmental problem.Studies on FA clearly shows that its application as an amendment to agricultural soils can significantly improve soil quality, and produce higher soil fertility. What FA application method is best and what level of application is appropriate for any one soil depends on the following factors: type of soil treated, crop grown, the prevailing agro climatic condition and the character of the FA used. Although utilizing FA in agricultural soils may help address solid waste disposal problems and may enhance agricultural production, its use has potential adverse effects also. In particular, using it in agriculture may enhance amounts of radionuclides and heavy metals that reach soils, and may therefore increase organism exposures in some instances.

Stability of cemented dried water hyacinth used for biosorption of radionuclides under various circumstances

This paper investigates the influence of frost attack and flooding conditions during disposal on the compressive strength, porosity and durability of cemented waste form contained dried and grinded water hyacinth. This plant was used as a phytoremediating agent to treat liquid waste simulate contaminated with radionuclides. The obtained results showed that an increase in the incorporated dry plants decreases the compressive strength and increases the porosity of the solidified waste form. Raising the number of freeze–thaw cycles was accompanied with noticeable increase in the mass-loss of tested specimens and unsteady trend of compressive strength and consequently the mechanical integrity. The presence and increase of immersion duration per turned positively the mass change and affect in different ways on the solidified waste form. Spectroscopic analyses such as infrared and X-ray as well as microscopic investigation were performed to evaluate the solidified waste form exposed to different undesirable climatic conditions during extending disposal durations. The use of Portland cement as a stabilizer for water hyacinth, following the phytoremediation process, achieves the requirements for durability and strength against the freeze–thaw cycles or flooding in different types of water during prolonged disposal.

Dielectric characterization of electro-coagulated boron waste

The source of electro-coagulation boron waste (ECBW) is wastewater. In order to remove boron from wastewater, boron carried to mud in the form of industrial solid waste is rinsed through electro-coagulation method. The dielectric dispersion properties of the ECBW were analyzed determining the parameters such as complex dielectric functions, dissipation factor and surface conductivity. It is found that at lower frequencies, ECBW sample exhibits a high dissipation factor. The Cole–Cole plots of the sample indicate that the dielectric dispersion mechanism is a Debye type. The boron waste exhibits a high resistance material behavior with a value of 1.03 × 109 ohm/sq. and this result is consistent with the electrical behavior of ECBW plate. This study has shown that due to its high resistance and high dielectric dissipation factor, ECBW can be a valuable material for use in many industrial applications which require electrostatic dissipation or electromagnetic shielding.

Immobilization of Simulated Borate Radioactive Waste Solution in Cement-Poly(methylmethacrylate) Composite: Mechanical and Chemical Characterizations

Solidified cured cement blocks containing different concentrations of the borate waste simulate were impregnated using methyl methacrylate monomer having 0.3% by weight benzoyl peroxide as initiator. Then, the polymerization process was completed by heating the impregnated blocks at ≈40°C. To define the suitability, range of applicability, and compatibility of the inert matrix used, relevant to the borate waste immobilized, the final radioactive borate waste forms are evaluated on the basis of their mechanical and chemical properties. Some factors that may affect the characterization of the obtained final waste form, for example, concentration of the incorporated borate waste solution simulate, aging of the solid waste form, before immersion, immersion in various leachants, and time of immersion, were followed systematically. It could be stated that cement-poly(methylmethacrylate) composite exhibited better mechanical and chemical characters compared to the cement as a unique matrix for immobilization of borate waste concentrates.

Leaching behavior of cement-natural clay composite incorporating real spent radioactive liquid scintillator

Handling, storage and final disposal of the generated radioactive liquid scintillator waste should be performed under controlled conditions to protect man and his environment. The significance of the present study is to evaluate chemical stability of cement-natural clay composite incorporating spent radioactive liquid scintillator waste. This waste is originated from daily counting and quantification of β-particles, weak gamma and x-ray. Increasing amounts of liquid scintillator waste immobilized in cement-natural clay composite were investigated. The obtained monolith solid waste forms were subjected to leaching characterizations under static or dynamic conditions. The factors that supposed to affect the leaching behavior of the final waste form, e.g. the amount of incorporated liquid scintillator waste, leachant type and leaching temperature were investigated. The leaching parameters namely cumulative fraction leached, effective diffusion coefficient and leaching index were evaluated under various experimental terms. Based on the data obtained and the leaching experiments performed for the proposed final waste form, it could be stated that the proposed composite formed from 3% natural clay related to the weight of Portland cement at ratio 0.3 of water/cement incorporating 15% of actual spent liquid scintillator radioactive waste could comply the required specifications for the disposal process at very exaggerating conditions.

Effect of blastfurnace slag addition to Portland cement for cationic exchange resins encapsulation

In the nuclear industry, cement-based materials are extensively used to encapsulate spent ion exchange resins (IERs) before their final disposal in a repository. It is well known that the cement has to be carefully selected to prevent any deleterious expansion of the solidified waste form, but the reasons for this possible expansion are not clearly established. This work aims at filling the gap. The swelling pressure of IERs is first investigated as a function of ions exchange and ionic strength. It is shown that pressures of a few tenths of MPa can be produced by decreases in the ionic strength of the bulk solution, or by ion exchanges (2Na + instead of Ca 2+ , Na + instead of K + ). Then, the chemical evolution of cationic resins initially in the Na + form is characterized in CEM I (Portland cement) and CEM III (Portland cement + blastfurnace slag) cements at early age and an explanation is proposed for the better stability of CEM III material.

Application of Zero Waste Concept on Milkfish Shredded Meat Processing

Shredded meat milkfish is one of fishery products made from steamed milk fish meat, making meat, seasoning, frying and squeeze that will produce shredded meat. This study aimed to identification of the waste types and the application of the zero waste concept in the processing of milkfish shredded meat in Shefish business group located at Bumi Agung 1 Residence Serang Banten Province. I n the process of making milk fish shredded meat waste is generated in the form of liquid and solid wastes. Liquid wastes include water fish washing results, steaming water and the juice of the fish meat. While the solid waste generated from the gills, guts, fish heads, skin and fins of fish, fish bones and condiments such as leather waste of onions and garlic skins . The application of zero waste concept through waste utilization optimizing the milkfish shredded meat processing can be done either on liquid and solid wastes. Utilization of liquid wastes such as water washing and boiling water containing soluble protein can be used as an ingredient in feed ducks pasta and flavor products. Utilization of solid wastes in the form of fish bones and spines can be used to fish bone meal, fish head waste can be processed into crackers calcium, and use of the intestines and gills can be used as raw fish silage or bekasang product. Milkfish skins and spins becomes to crispy product. Waste generated in the milkfish shredded meat processing of Shefish business groups are used yet. The application of zero waste concept by optimizing the utilization of waste is one of the effective and efficient solutions to prevent in the fish processing waste. Keywords: milkfish shredded meat, zero waste, waste, optimizing

Cementation of Bioproducts Generated from Biodegradation of Radioactive Cellulosic-Based Waste Simulates by Mushroom

The current work was devoted to study the solidification of bioproducts originated from the bioremediation of mixture of solid cellulose-based radioactive waste simulates using a mushroom (Pleurotus pulmonarius), in Portland cement. The obtained solidified waste form was subjected to mechanical integrity qualification after curing periods of 28 and 90 days. Chemical performance of the cement-waste form was also evaluated in different leachant media during 540 days. The results obtained gave useful information about the mechanical, physical, and chemical performances of the final cement-waste form incorporated the radioactive bioproducts. Moreover, it indicated that cement can provide a highly durable form that ensures a long-term stability of the solidified waste material and can act as a first barrier against the release of radiocontaminants from radioactive wastes to the surrounding environment.

Environmental performance analysis of Chinese industry from a slacks-based perspective

The industry activities produce massive bad by-products, in the form of waste water, waste gas or solid waste, which are the source of environmental issues. The growing concerns over environmental problems make China reconsider the current developing pattern, and partially necessitate the reformation of economic structure. If the environmental consequences from economic structure reformation are subject to empirical testing, it is of vital importance to make some actual measurement for environmental performance. To achieve this goal, this paper proposes a slacks-based environmental efficiency index based on data envelopment analysis (DEA). An empirical application to industry sector of China presents the following findings: (1) approximately two-thirds of the nation’s provinces are inefficient due to excessive resource utilization, insufficient products or considerable quantities of wastes; (2) Spearman test shows that SO2 and solid waste intensity have more impacts on industrial aggregated efficiency than those of electricity and COD intensity do, which implies that waste gas and solid waste should be paid more attention in pollution abatement; (3) the environmental protection activities have yielded the expected benefits, as the aggregated efficiency of regional industry has been on a rising trend during the past decade; (4) the west region of China has been developing quickly in recently years and performs well both in economy and environmental control.

A study conducted on the impact of effluent waste from machining process on the environment by water analysis

Ferrous block metals are used frequently in large quantities in various sectors of industry for making automotive, furniture, electrical and mechanical items, body parts for consumables, and so forth. During the manufacturing stage, the block metals are subjected to some form of material removal process either through turning, grinding, milling, or drilling operations to obtain the final product. Wastes are generated from the machining process in the form of effluent waste, solid waste, atmospheric emission, and energy emission. These wastes, if not recycled or treated properly before disposal, will have a detrimental impact on the environment through air, water, and soil pollution. The purpose of this paper is to determine the impact of the effluent waste from the machining process on the environment through water analysis. A twofold study is carried out to determine the impact of the effluent waste on the water stream. The preliminary study consists of a scenario analysis where five scenarios are drawn out using substances such as spent coolant, tramp oil, solvent, powdered chips, and sludge, which are commonly found in the effluent waste. The wastes are prepared according to the scenarios and are disposed through the Institute of Product Design and Manufacturing (IPROM) storm water drain. Samples of effluent waste are collected at specific locations according to the APHA method and are tested for parameters such as pH, ammoniacal nitrogen, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, and total suspended solids. A subsequent study is done by collecting 30 samples of the effluent waste from the machining operations from two small- and medium-scale enterprise locations and the IPROM workshop to test the quality of water. The results obtained from the tests showed high values of chemical oxygen demand, ammoniacal nitrogen, and total suspended solids when compared with the Standard B specification for inland water bodies as specified by the Department of Environment, Malaysia.