OPERATIONAL EFFICIENCY AND ENVIRONMENTAL IMPACT OF WASTEWATER TREATMENT PLANTS IN LITHUANIAN RURAL AREAS

Abstract

The aim of the paper was to determine the operational efficiency and environmental impact of five small wastewater treatment plants (WWTPs) in Ukmergė district. The efficiency of these WWTPs, reconstructed by applying the same vertical flow labyrinth technology was calculated according to the most important pollution indicators: biochemical oxygen consumption in 7 days (BOD₇), total phosphorus (TP) and total nitrogen (TN) in period 2017-2020. It was found that the lowest operational efficiency of Taujėnai wastewater treatment plant was according to BOD₇ (94-96%). The lowest treatment efficiency of total nitrogen was determined in Dainava WWTP (88-95%). The highest treatment efficiency according to total phosphorus was in Šventupė WWTP (86-92%), the lowest in Žemaitkiemis WWTP (72-85%). In order to evaluate the impact of wastewater treatment plants on the environment, their Life Cycle Assessment (LCA) was performed. Sludge from wastewater treatment process has been found to have the highest environmental impact and fuel consumption for transport the lowest. Of the five wastewater treatment plants examined, the Vidiškiai wastewater treatment plant has the largest impact on the environment, and Šventupė WWTP has the lowest.