Impact of Coronavirus Spread Prevention Actions on Sewage Quantity and Quality

Abstract

Background: Spread prevention actions (SPAs) during Coronavirus pandemic period, such as increased hand-washing, temporary lock-downs, preventions in transportation, and the reduction of recreational and industrial activities may change the routines in social behaviors. Accordingly, SPAs can be effective on the quality and quantity of raw municipal wastewater. This research evaluates the aforementioned hypothesis and recommends solutions for the proper operation of wastewater treatment plants (WWTPs). Methods: For this purpose, the quantity and quality of sewage in 23 municipal WWTPs in Isfahan province, as the study area, were surveyed and compared from 2015 to 2020. SPSS software (version 23) was used for statistical analysis. Results: Results indicated that the annual growth rate of sewage discharged in the spring and summer of 2020 (period of SPAs) in the study area is 24% more than the average of annual growth rate in long-term (2015)(2016)(2017)(2018)(2019). This increase is 45% in small WWTPs, while it is only 5% in large WWTPs. Results also revealed that the concentration of chemical oxidation demand (COD) of sewage was reduced 24% on average in this period. In addition, the biodegradability of wastewater is increased in large WWTPs mainly due to the decrease of industrial activities. Conclusion: Therefore, SPAs in the pandemic period of Coronavirus could increase the quantity of municipal wastewater and reduce its COD concentrations. These variations may provide more appropriate operational conditions for waste stabilization ponds rather than activated sludge units.