According to EU regulations, member states shall take measures to encourage the recycling of biowaste in a way that fulfils a high level of environmental protection. In Spain, the separate collection of biowaste is only implemented in some regions. For this reason, a pilot scheme based on an information campaign and the location of a specific brown container for biowaste in specific zones of the city was carried out in Castelló de la Plana (Spain) over a period of six months. In this period, the collection and composition of the biowaste was monitored in depth with the goal of determining the evolution of the efficiency of the new collection system over time. In the zones, the quality rate in the biowaste container increased as the pilot study progressed, finally reaching 90%. The rate of biowaste separation also increased in the three zones over time, although in different ways, which means that there is greater collaboration on the part of citizens. On the other hand, an analysis of the rate of net biowaste daily collection from zones 2 and 3 has shown that their value increases as the rate of containerization of biowaste decreases. Therefore, to obtain better results it will be necessary to increase the containerization of biowaste, that is, to reduce the distance from the citizen to the container. It can thus be said that there is a positive evolution of the experience, which boosts confidence when it comes to implementing the system throughout the city.

This paper presents, firstly, the influence of the geometry of a slope in the safety factor (SF). In order to do this, the SF is compared among three types of slopes: with berms every 7 m high and a dam at the toe, without berms and with a dam at the toe, and without berms nor dams. It was observed that, for the same inclination, the berms do not significantly influence the stability. However, the construction of an earth dam at the base increases safety, especially with little height and slope in waste with poor mechanical properties. On the other hand, a set of diagrams to learn, quickly and easily, the safety factor of a landfill slope has been developed. Thus, this set of diagrams allows calculations from the SF height (from 17 to 80 m) and slope inclination (from 45° to 14°) with values of effective cohesion of the waste (C'o) from 1 to 3 t/m 2 and effective friction angle (Φ') of 10° to 25°.

The characteristics and properties of waste in a landfill, and its evolution over time, are difficult to estimate because of the heterogeneity of materials, biomass degradation, density, cover material, and infiltration of water. In this work, a lysimeter was used to simulate how refuse from mechanical-biological treatment (MBT) plants evolved in a landfill over a 45-day period. Water was added as a way to imitate the effects produced during rainy seasons. Field capacity and changes in the physical and chemical properties (volatile solids, biomass, and heating value) were analyzed. The results of this research show that the percentage of biomass lowers, and the heating value increases, after bringing about infiltration and percolation of water in the waste mass. Therefore in order to stabilize waste in a landfill, employing irrigation or leachate recirculation could be advisable. As the heating value increases after percolation, it could also be a good idea to recover the fuel material after stabilization.

This paper describes the laboratory-scale simulation of the behaviour of rejects from a biological-mechanical treatment (BMT) plant in Castellón (Spain). For this purpose, four lysimeters were built, with different densities. Simulations were carried out for 7 weeks and leachate recirculation was applied to two of them. The experimental results allowed us to determine: (i) dirt in fractions, which was relatively high (up to 15% in some fractions) due to biological processes; (ii) the field capacity for this waste with similar values to other works, which varied depending on the experiment; (iii) variation in the biomass percentage which lowered after experiments in all cases (59.5% lower on average), and the rejects’ calorific value was higher after experiments (28.2% on average); (iv) the evolution of leachate properties with or without recirculation, where percolation, in addition to the dragging of soluble materials, stabilised waste, which diminished its biological activity. Rejects’ increased calorific value will allow combustible material to be recovered in the future as a way to exploit the energy potential stored in landfills.

Background:According to EU regulations, member states shall take measures to encourage the recycling of biowaste in a way that fulfils a high level of environmental protection. In Spain, the separate collection of biowaste is only implemented in some regions. For this reason, a pilot scheme based on an information campaign and the location of a specific brown container for biowaste in specific zones of the city was carried out in Castellón de la Plana (Spain) over a period of six months. In this period, the collection and composition of the biowaste was monitored in depth with the goal of determining the evolution of the efficiency of the new collection system over time. Results:In the zones, the quality rate in the biowaste container increased as the pilot study progressed, finally reaching 90%. The rate of biowaste separation also increased in the three zones over time, although in different ways, which means that there is greater collaboration on the part of citizens. On the other hand, an analysis of the rate of net biowaste daily collection from zones 2 and 3 has shown that their value increases as the rate of containerization of biowaste decreases. Conclusions:In order to obtain better results in the biowaste quality rate it will be necessary to increase the containerization of biowaste, that is, to reduce the distance from the citizen to the container. It can thus be said that there is a positive evolution of the experience, which boosts confidence when it comes to implementing the system throughout the city.