Despite efforts to utilise bauxite residue, the amount of red mud stored in reservoirs is increasing. This paper aims to evaluate the potential of red mud and other sludge waste types as a soil substitute by monitoring plant development. Pot experiments were carried out testing two types of mixtures: dredging sludge from Lake Balaton mixed with garden soil and the sewage sludge and soil blend. These were then treated with red mud (15 and 30% w/w). The plants were under-, while the roots were more developed in the sewage sludge mix than the dredging sludge blend and the control soil. In the sewage amendment, the phosphorous content increased while the calcium content was lower than in the other soil types and the optimum. The metals uptake of the plants was a factor of the red mud quantity. Lead, nickel, titanium and silicon had elevated concentrations parallel to higher red mud content, but only the nickel exceeded the threshold of the Hungarian legislation. Silicon and titanium were beneficial for plant growth, compensating for the potentially toxic effects of lead and nickel. Results suggest that the red mud in a mixture with either sewage sludge or dredging sludge can act as catalysts for the growth rate of test plants, allowing their utilisation as secondary raw materials.
The research subject is the deposit-refund system of beverage packaging (PET, glass and aluminium) in Hungary, which is under development. For the success of the planned system, it is important to consider the population’s opinion. Therefore, data from a primary questionnaire survey were used for the analyses. This questionnaire was conducted in 2020 and resulted in an evaluable sample of 20,430 people. The study aims to answer the following research questions (Q). Q1. Does the reform of the beverage packaging deposit-refund system in Hungary have a raison d’être? Q2. What are the demographic characteristics (gender, type of residence, qualification) of those who would redeem beverage packaging in their households if the state paid for it? Q3. Do the demographic characteristics and/or the environmental attitudes of individuals significantly influence their perceptions of the planned new system, and how strong is the relationship between them? As for the method for answering the research questions, descriptive statistics and relationship analyses (Cramer’s V and Kendall’s tau) were applied to the closed answers. The results show that the analysis of the primary research provides well-determined directions for legislators and decision makers who develop the detailed operating rules of the new system.