The analysis of the sewage changes quality during treatment processes on the wastewater treatment plant in Przemyśl

On the basis of the noted BOD5, CODCr, total nitrogen (Ntot.) and total phosphorus (Ptot.) values in sewage treated in 2015 on the Wastewater Treatment in Przemyśl, the evaluation of the sewage biodegradability was performed. The conducted analysis showed that the composition of raw sewage provided proper biochemical processes and its effectiveness, which is evidenced by the calculated CODCr/BOD5, Ntot./BOD5 and Ptot./BOD5 ratios. Moreover, the changes of pollutants indicators in the sewage after the next treatment stages were analyzed. As the sewage treatment process progressed, there was a gradual reduction of the organic and biogenic compounds. The largest reduction was achieved as a result of biological processes. The obtained results indicate the reliability of treatment processes in the two-stage system of Przemyśl wastewater treatment plant.