This paper deals with waste management in the tourism sector, specifically in the agro-tourism structures. Two regions of Romania and Italy have been considered as case studies in order to promote good practices and actions for sustainable municipal solid waste management. Specific criteria to adopt for the sustainable consumption of beverages and food and for the sustainable use of packaging of various types have been analyzed and suggested. The adoption of an indicator at the level of the single tourist structure has been proposed to help self-analysis that is aimed at setting the priorities of intervention for improving its environmental sustainability.

This paper introduces the preliminary results of a development project focused on waste recycling and recovery in La Paz (Bolivia). The aim is to share best practices and to present real-world challenges when implementing appropriate waste management systems in developing countries. Environmental pollution, social inequality, lack of resources, and economic discrepancies are challenges still present in the 21st century, and a global call-for-action is needed to support sustainable development. The project “LaPazRecicla”, financed by the Italian Agency for Development Cooperation, provides perspectives that are potentially useful for policy-makers, waste management practitioners, and circular economy visionaries. The article aims to present the effective contribution of the practical actions to the local municipality, and to introduce the reason for why theoretical methods were employed to support the project. The outcomes provided two main indications: on one hand, cooperation among interdisciplinary actors and financial support can give the chance of improvement, suggesting international donors should continue in this direction; on the other, political instability, lack of local technical knowledge, and the absence of planning for a long-term period makes these actions unsuitable for tangible change. Global reflections are required in order to measure the potential benefits of small-scale projects, evaluating the time needed to move towards a sustainable future in low-income countries.

Soils contaminated with organic substances is an important issue across Europe: In some areas, these are the main causes of pollution, or the second after contamination from waste disposal. This paper included an experimental application that compared three methods of remediation of contaminated sites, based on electric fields: A single treatment (electroremediation); and two combined treatments, phyto-electrochemical and electrooxidation (a combination of chemical treatment and a DCT—direct current technology). The contaminated soil was taken from a former industrial area devoted to oil refining, located between two roads: The one national and the other one for industrial use. Nine soil samples were collected at two depths (0.2 and 0.4 m). The initial characterization of the soil showed a density of 1.5 g/cm³ and a moisture of about 20%; regarding grain size, 50% of the soil had particles with a diameter less than 0.08 mm. The electrochemical treatment and electrooxidation had an efficiency of 20% while the two combined methods had efficiencies of 42.5% for electrooxidation (with H₂O₂) and 20% for phyto-electroremediation (phyto-ER) with poinsettias.

The biological denitrification process is extensively discussed in scientific literature. The process requires anoxic conditions, but the influence of residual dissolved oxygen (DO) on the efficiency is not yet adequately documented. The present research aims to fill this gap by highlighting the effects of DO on the specific denitrification rate (SDNR) and consequently on the efficiency of the process. SDNR at a temperature of 20 °C (SDNR_20°C) is the parameter normally used for the sizing of the denitrification reactor in biological-activated sludge processes. A sensitivity analysis of SNDR_20°C to DO variations is developed. For this purpose, two of the main empirical models illustrated in the scientific literature are taken into consideration, with the addition of a deterministic third model proposed by the authors and validated by recent experimentations on several full-scale plants. In the first two models, SDNR_20°C is expressed as a function of the only variable food:microrganism ratio in denitrification (F:M_DEN), while in the third one, the dependence on DO is made explicit. The sensitivity analysis highlights all the significant dependence of SDNR_20°C on DO characterized by a logarithmic decrease with a very pronounced gradient in correspondence with low DO concentrations. Moreover, the analysis demonstrates the relatively small influence of F:M_DEN on the SDNR_20°C and on the correlation between SDNR_20°C and DO. The results confirm the great importance of minimizing DO and limiting, as much as possible, the transport of oxygen in the denitrification reactor through the incoming flows and mainly the mixed liquor recycle. Solutions to achieve this result in full-scale plants are reported.