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Two laboratory tests were carried out to verify the suitability of an Italian commercial biochar as an adsorbing material. The chosen contaminant, considered dissolved in groundwater, was As. The circular economic concept demands the use of such waste material. Its use has been studied in recent years on several contaminants. The possibility of using an efficient material at low cost could help the use of low-impact technologies like permeable reactive barriers (PRBs). A numerical model was used to derive the kinetic constant for two of the most used isotherms. The results are aligned with others derived from the literature, but they also indicate that the use of a large amount of biochar does not improve the efficiency of the removal. The particular origin of the biochar, together with its grain size, causes a decrease in contact time required for the adsorption. Furthermore, it is possible that a strong local decrease in the hydraulic conductibility does not allow for a correct dispersion of the flow, thereby limiting its efficiency.

In this study, the long-term tailing derived from the storage process of contaminants in low-permeability zones is investigated. The release from these areas in the groundwater can be considered a long-term source that often undermines remediation efforts. An Image Analysis technique is used to analyze the process and evaluate the concentrations of a tracer at different points of the test section. Furthermore, the diffusive flux from the low-permeability lenses is determined. To validate the proposed technique, the results are compared with samples, and the diffusive fluxes resulting from the low-permeability zones of the reconstructed aquifer are compared with a theoretical approach.

Municipal Solid Waste (MSW) management is a major concern for all urban areas, which needs to be accomplished referring to integrated strategies, especially when it has to be applied to developing countries where often the costs can condition the choice and the environmental costs could arise too much. Strategies can be effective only as a result of commonly shared analyses and choices with respect to the whole involved territory taking into account financial and environmental costs. This paper presents a model for the implementation of integrated MSW management policies which can result extremely useful also in developing countries where the system must still has to be refined or built. Generally the approach uses different scenarios based on the environmental, social, economic and technological conditions of the specific area and on its developing potential.The model provides the best solid waste (SW) flows allocation/distribution among the available treatment and disposal options by minimizing the total cost by means of a optimization procedure. The environmental impact of the resulting scenario can then be estimated by means of a Life Cycle Assessment (LCA)-based procedure. Such a model can be useful as a support in decision making for both governmental and non-governmental institutions involved in the planning of MSW management strategies. The big advantage with respect to other user friendly software, which are present in Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation literature, is surely that it is specialised on the topic on the SW management and therefore it can point directly, being extremely easy to modify or to adapt to other scenarios, at the optimal configuration of the specific case.

Integrated waste management and sustainable use of natural resources are the basis of the Green Economy. In this context, the management of the Municipal Solid Waste Incineration Bottom Ashes (MSWI BA) is one of the current issues worldwide. This paper presents an application of the Life Cycle Assessment (LCA) procedure to the industrial production of ceramic tiles using bottom ashes in the mixture together with feldspathic sands and clays. The comparison between ashes and traditional mixture showed a similar mineralogical and rheological composition. In the reported procedure the MSWI BA, after storage, were treated to separate and recover metals. The residual ashes were added to the mixture and then they followed the traditional industrial production cycle. Samples of the different materials were taken during the experimental industrial activity and leaching tests were carried out to verify the environmental compatibility of MSWI BA use to produce ceramic tiles. The results of the LCA show large environmental and energy benefits related to the proposed reuse of BA. Metal recovery and lower use of clay in traditional mixture avoids emission of substances with a negative potential impact for environment. This study provides a sustainable alternative to the MSWI BA final disposal in landfill as MSWI BA are hazardous wastes that present complicated management and high disposal costs.

Secondary clarifiers are demanded to separate solids created in activated sludge biological processes to achieve both a clarified effluent and to manage the biological processes itself. Indeed, the biological process may influence the sludge characteristics, and conversely, the settling efficiency of the sedimentation basin plays an important role on the biological process in the activated sludge system. The proposed model represents a tool for better addressing the design and management of activated sludge system in wastewater treatment plants. The aim is to develop a numerical model which takes into account both the conditions in the biological reactor and the sludge characteristics coupled to the hydrodynamic behavior of a clarifier tank. The obtained results show that the different conditions in the reactor exert a great influence on the sedimentation efficiency.

Zerovalent iron nanoparticles (nZVI) are becoming one of the most widely recommended nanomaterials for soil and groundwater remediation. However, when nZVI are injected in the groundwater flow, the behavior (mobility, dispersion, distribution) is practically unknown. This fact generally results in the use of enormous quantities of them at the field scale. The uncertainties are on the effective volumes reached from the plume of nZVI because their tendency to aggregate and their weight can cause their settling and deposition. So, the mobility of nanoparticles is a real issue, which can often lead to inefficient or expensive soil remediation. Furthermore, there is another aspect that must be considered: the fate of these nZVI in the groundwater and their possible impact on the subsoil environment. All these considerations have led us to propose an application of nZVI simulating the permeation technique through a laboratory experience, finalized to have a better, or even simpler description of their real behavior when injected in a flow in the subsoil. A two-dimensional laboratory-scale tank was used to study the dispersion and transport of nZVI. A nZVI solution, with a concentration equal to 4.54 g/L, was injected into glass beads, utilized as porous medium. The laboratory experiment included a digital camera to acquire the images. The images were then used for calibrating a numerical model. The results of the mass balance confirm the validity of the proposed numerical model, obtaining values of velocity (5.41 × 10−3 m/s) and mass (1.9 g) of the nZVI of the same order of those from the experimental tests. Several information were inferred from both experimental and numerical tests. Both demonstrate that nZVI plume does not behave as a solute dissolved in water, but as a mass showing its own mobility ruled mainly from the buoyancy force. A simple simulation of a tracer input and a nZVI plume are compared to evidence the large differences between their evolution in time and space. This means that commercial numerical models, if not corrected, cannot furnish a real forecast of the volume of influence of the injected nZVI. Further deductions can be found from the images and confirmed by means the numerical model where the detachment effect is much smaller than the attachment one (ratio kd/ka = 0.001). From what is reported, it is worthwhile to pay attention on the localization of the contaminants source/plume to reach an effective treatment and it is important to go further in the improvement of solution for the limiting the nanoparticles aggregation phenomenon.