Most of the energy content of wastewater can be found in wastewater heat, however, its recovery is limited. In this article, the current situation, future opportunities of wastewater heat recovery are presented based on secondary data collection, mentioning the constraints and main influencing factors of sustainable implementation of heat recov...ery systems in Hungary. Besides, the already existing systems are described. As regards the capacities of treatment plants, 103 of the 574 domestic plants have a capacity of over 20,000 Population Equivalent (PE), of which 25 plants have a capacity of over 100,000 PE. According to our calculations, in big cities/capitals (20.000 – 100.000, and over 100.000 inhabitants), it may be possible to recover wastewater heat sustainably in several places. In small towns (5.000 – 20.000 inhabitants), wastewater heat recovery can be technologically and economically sustainable only in the presence of agricultural or industrial plants with high and continuous wastewater feed into the pipeline system. Taking into account the temperature conditions at each place of use and their estimated fluctuations, it can be said that proper, careful planning, sizing and implementation have a crucial effect on the efficiency of microbiological activity in the treatment plants. In bigger cities, of course, the effect of the temperature drop of one main collector may be minimal, however, in smaller and medium-sized settlements, excessive heat extraction may result in complete inhibition or cessation of nitrification. In Hungarian case studies, the maximum acceptable temperature drop is approx. 2-3 °C. It can be stated that energy recovery from wastewater may be very promising considering the size and temperature limitations. Therefore, the rational recovery of wastewater heat can be an important part of the implementation of circular economy and sustainable energy utilization in wastewater management, resulting in significant energy savings and pollutant reduction.
JEL CODE: Q25
This paper focuses on the economic and statistical evaluation of the production technology findings of the polyfactorial maize production experiments carried out between 2015-2017 at the Látókép Experiment Site of the University of Debrecen, Faculty of Agricultural and Food Sciences and Environmental Management. The examined agrotechnical fa...ctors included irrigation, previous crop, tillage, crop density, hybrid and N nutrient supply, while the effect of different crop years was taken into consideration. In addition to descriptive statistical methods, we used multivariate regression analysis during the statistical evaluation. In the course of the evaluation, we examined three models that differed in terms of tillage methods and the consideration of crop year. In our best fit model, the factors were 71% responsible for the change in yield value. We carried out efficiency and comparative analyses in the course of the economic evaluation.
Averaged over the three examined years, it can be stated that nutrient supply and crop year had an outstanding effect on yield, while irrigation had a minimal effect. However, global warming may justify irrigation in the future, not only from a biological point of view, but also from an economic aspect.
Ideal tillage is also greatly affected by crop year, too. Altogether, of the examined tillage systems, subsoiling proved to be the best from an economic point of view.
Our investigations confirm that it is better to perform intensive farming under more favourable market conditions. The optimum of N fertilisation is probably outside of the range we examined, if the extreme changes in maize and fertiliser prices are ignored.
JEL Classification: Q16, Q12, Q13, O32
The negative impacts of human activities on the environment and nature can be felt worldwide. Thus there is a growing focus on measurements that keep sustainability in mind. As one of the main pioneers of environmental protection and sustainability efforts, these aspects are more and more prevalent in the current environmental policy of the Eur...opean Union (EU). In this review article, the development of the environmental policy of the EU is presented. After listing the main milestones, the role of the EU in the area of environmental protection, the frameworks built around the goals and the roles of the institutions are discussed. Then – with an international detour – the details of the Paris Agreement about climate change and the state of the 20/20/20 commitments are summarised. In the remaining parts of the article, the focus is on the climate protection goals of the EU for the next three decades, the expected future directions, and the agenda of the von der Leyen Commission concerning climate protection. An important step and tool for achieving the goals set until 2050 is to incorporate climate and environmental protection elements to the 2021-2027 budget of the EU. In order to achieve the expected effects, it is crucial to develop the right tools of the environmental policy, to form a widespread cooperation, to raise awareness, and incentivise and support the innovative solutions in the sustainability area.
In my article, after describing the characteristics of recent wastewater treatment activity, I introduce different traditional and innovative energetic opportunities of the compulsory waste management activities at large-scale operational level, covering national and international examples. Furthermore, the wastewater-based biomethane productio...n and the certain plant’s energy self-sufficiency are highlighted topics as well. In the former case, it is possible to utilize the wastewater-based biomethane as fuel (and even to operate own vehicle fleet), while the second one gives the opportunity for the internal usage of produced electricity and waste heat, which can also result in significant cost-savings. As an additional option, algae-based wastewater post treatment is presented, based on the conditions of a Hungarian wastewater treatment plant, which biogas production efficiency and thus energy self-sufficiency has developed favourably due to the technological improvements. These plants may have a twofold role in the future: they are responsible for the compulsory waste management activity and on the other hand they can serve as excellent raw material mines.
JEL Code: Q25