This paper presents the use of multi-criteria analysis as a tool that helps choosing an adequate technology for a household wastewater treatment plant. In the process of selection the criteria of sustainable development were taken into account. Five municipal mechanical-biological treatment plants were chosen for the comparative multi-criteria analysis. Different treatment technologies, such as sand filter, activated sludge, trickling filter, a hybrid system - activated sludge/trickling filter and a hybrid constructed wetland system VF-HF type (vertical and horizontal fl ow) were taken into account. The plants’ capacities were 1 m³∙d^-1 (PE=8) and they all meet the environmental regulations. Additionally, a solution with a drainage system was included into the analysis. On the basis of multi-criteria analysis it was found that the preferred wastewater treatment technologies, consistent with the principles of sustainable development, were a sand filter and a hybrid constructed wetland type VF-HF. A drainage system was chosen as the best solution due to the economic criteria, however, taking into consideration the primary (ecological) criterion, employment of such systems on a larger scale disagree with the principles of sustainable development. It was found that activated sludge is the least favourable technology. The analysis showed that this technology is not compatible with the principles of sustainable development, due to a lack of proper technological stability and low reliability.

The valorisation of sewage sludge for sustainable agricultural use and biofuel production proposes an effective and beneficial management of sewage sludge in a closed-loop cycle. The management of sewage sludge biowaste is a rising problem due to increasing waste storage expenses. In this sense, the use of circular economy principles in sewage sludge management creates opportunities to develop new technologies for processing. The biorefinery model allows the application of wasteless technologies via sewage sludge valorisation in terms of agricultural use and biofuel production, especially with the hydrothermal carbonisation method. Applying hydrothermal carbonisation in the treatment of biosolid sewage sludge has numerous benefits due to processing highly hydrated organic waste into carbon hydro char, a high-quality solid biofuel. The direct use of sewage sludge in the soil does not allow for full use of its functional properties. However, the hydrothermal carbonisation of sewage sludge results in biocarbon pellets, making it a viable approach. This work also discusses the barriers (legal, chemical, biological, and technical) and possibilities related to sewage sludge biorefining processes.

As a waste neutralization facility, the landfill is a kind of bioreactor producing landfill gas or (LFG) - biogas, which should be captured and neutralized for environmental reasons. One of the ways of its utilization is the combined production of heat and electrical energy in combined heat and...