| Abstract [eng] |
The circular economy is a completely new and high-potential economic model with which the European Union seeks to reorient the environment protection and the economy. The main goals of this model are to reduce the amount of generated waste, extend items lifetime, recycle and recover as many resources as possible from obsolete products. Sewage entering sewage treatment plants are no longer considered to be a waste that only needs to be treated and discharged. Nutrients, energy and water can be recovered from sewage and sewage sludge. All European Union countries use different treatment methods in order to manage wastewater and sludge as efficiently and rationally as possible, Lithuania is no exception. In this paper, municipal wastewater treatment plants in agglomerations larger than population equivalent of 2000 were analyzed. To assess the available circularity potential of the country, 11 indicators were selected. The circularity of Lithuanian wastewater treatment plants is analyzed for the first time, therefore it was decided to analyze the period of 2018-2020 in order to compare the changes. Data taken from international databases allowed to compare Lithuania's results with those of other European Union members. All indicators are arranged according to the circular economy model for the water and wastewater sector, which includes prevention, disposal, reuse, recycling, recovery and rethinking. Most of the indicators were chosen to assess the removal of pollutants, as this is the main function performed by wastewater treatment plants. In Lithuanian wastewater treatment plants, the reuse and processing of wastewater is not carried out in any of the treatment plants, due to the high price of such works and low demand. However, due to hotter summers, climate change and more frequent droughts, water recovery from wastewater may become popular in Lithuania as well. Indicators of water consumption productivity and connection to centralized wastewater networks have been selected for reduction and prevention. The obtained values showed that water resources are used rationally in the country. Sewage sludge is an excellent raw material from which nutrients and energy can be recovered. In Lithuania, sewage sludge is mainly used in agriculture and compost production, and in recent years more and more quantities have been incinerated. Compared to 2010, when more than half of all sludge was stored at the site, by 2020 this figure was less than 10 %. During this time, the country's wastewater treatment plants have optimized their processes and found markets, which use sewage sludge for their operations. Although Lithuanian wastewater treatment plants do not apply new and modern methods of nutrient recovery, the successful application of the principles of the circular economy in the activities is observed in many of the analyzed areas. |
