New Assessment of the Analysis of Wastewater Quality on a Wastewater Treatment Plant Using the RAPS Method

Abstract

Water is an important factor in human health and an essential ingredient of living organisms. The increase in population and living standards has led to increased water consumption, consequently causing an increase in wastewater, as well as greater quality impairment. Wastewater treatment of the public mixed drainage system of the city of Čakovec (Croatia) and surrounding suburban settlements is carried out by mechanical and biological procedures, with the final treatment of separated sludge. In this paper, we analyzed the input and output values of annual time series for chemical oxygen demand (COD) on the wastewater treatment plant in 2015 using the RAPS method (Rescaled Adjusted Partial Sums). The results showed that the input series contained more pronounced subseries with respect to their mean values and trends of increase and decrease, respectively. When comparing the input and output subseries, the output subseries does not oscillate to a large extent given that they express the output quality of wastewater. A significant reduction in the output values of the indicators determines the quality treatment of incoming wastewater.

Keywords

• wastewater
• treatment plant
• quality
• time series
• RAPS