ANALYSIS OF THE IMPACT OF SODIUM HYPOCHLORITE ON THE RIVER IBAR DURING THE COVID-19 PANDEMIC.

The situation caused by Covid-19 pandemic has caused impact on environment, due to the limited human activities, and actions against Covid-19 spread. In this paper there will be presented the results of the experimental investigation of using sodium hypochlorite for disinfection purposes to the river Ibar water quality and aquatic organisms. The city streets and buildings were disinfected on daily basis, and the waste waters were collected into storm water pipelines, directed to the sewerage and discharged into the river. There is no waste water treatment facility involved, and the domestic sewage was mixed with storm water flow, entering the river at the same discharge point. For better understanding of this impact, the results from the physical, chemical and micro biological testing of the river water quality were compared to the pre-Covid time. The results have shown that the river is III class of water, and the values for Nitrate, Nitrite and BOD were exceeding the values for the III class. The concentration 0.1% of NaOCl is sufficient to eliminate Proteus mirabilis, Proteus vulgaris, Pseudomonas aeruginosa during the exposure time of 5 min. Since these microorganisms, which are often found in surface waters and are sensitive on low concentrations of disinfectants, were not isolated in the sample analysis, this can be contributed to sodium hypochlorite. As the river Ibar is natural recipient of all wastewater from the north part of this region, it is necessary to continuously monitor water quality and implement protection measures, in anticipation of the wastewater treatment plant construction. [ABSTRACT FROM AUTHOR]