Milica Karanac

Landfill design: need for improvement of water and soil protection requirements in EU Landfill Directive

This paper deals with environmental policy issues related to a landfill design. The final product of numerous waste treatments should be placed on a landfill. Before waste disposal, the ground should be protected by a mineral layer with properties required by the related regulation. In order to prevent environment pollution, EU adopted the Landfill Directive 1999/31/EC. The most important technical requirements related to the characteristics of the layer material are water permeability and thickness. The performed comparative national regulatory analysis raised the question of the need for more uniform elaboration of the directive requirements over the whole European Union area (including EU candidates). The choice of the material for the impermeable mineral layer, which should be made during landfill design, is a very important decision. Methods for the determination of the permeability coefficient were analysed, showing that the Directive should define hydraulic gradient as a physical quantity and define its value through measurement of the permeability coefficient. The paper analyses whether some parts of the Directive, as landfill design BAT and base for national legislative acts, require further elaboration in order to provide sufficient information about proper protection of soil and water. Using integrated approach, seven amendments on the directive annex I were suggested related to (a) the meaning of the term artificially established geological barrier, (b) layer thickness, (c) water permeability coefficient determination, (d) mineral layer lifecycle, (e) the meaning of the term sealing and (f) leaching control of material joints.

Efficient multistep arsenate removal onto magnetite modified fly ash

The modification of the fly ash (FA) by magnetite (M) was performed to obtain FAM adsorbent with improved adsorption efficiency for arsenate removal from water. The novel low cost adsorbents are characterized by liquid nitrogen porosimetry (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), Mössbauer spectroscopy (MB) and Fourier transform infrared (FTIR) spectroscopy. The optimal conditions and key factors influencing the adsorbent synthesis are assessed using the response surface method (RSM). The adsorption experiment was carried out in a batch system by varying the contact time, temperature, pH, and mass of the adsorbent. The adsorption capacity of the FAM adsorbent for As(V), calculated by Langmuir model, was 19.14 mg g-1. The thermodynamic parameters showed spontaneity of adsorption with low endothermic character. The kinetic data followed the pseudo-second-order kinetic model (PSO), and Weber-Morris model indicated intra-particle diffusion as rate limiting step. Alternative to low desorption capability of the FAM was found by five consecutive adsorption/magnetite precipitation processes which gave exhausted layered adsorbent with 65.78 mg g-1 capacity. This research also has shed light on the mechanism of As(V)-ion adsorption, presenting a promising solution for the valorization of a widely abundant industrial waste.