Seasonal variation pattern of physicochemical and microbial parameters in a wastewater treatment plant
Abdalrahman Alsulaili, Bushra Y. Al-Buloushi, Mohamed F. Hamoda
Abstract
ABSTRACT Wastewater discharge contains a high level of contaminants that require sufficient treatment for further reuse and legitimate applications. This study examined the effect of seasonal variations on treatment performance. Data was generated daily from January 2013 to December 2016, analyzing the samples from different stages that is, influent, secondary and tertiary effluents. The results for microbial parameters showed that in the influent, fecal coliforms had the highest levels in fall, while the coliform count had the highest levels in winter, with Salmonella, fecal streptococci and fungi presenting better resistance and survival in spring. However, the physicochemical parameters, for example, pH and conductivity, of the influent and treated effluents did not vary with season, but slight variations occurred in all other parameters. In fall, chemical oxygen demand, volatile suspended solids and total suspended solids showed minimal changes in the tertiary-treated effluent, while biochemical oxygen demand 5 showed no significant changes in all seasons. The coefficient of variation and coefficient of reliability showed minimal variability in plant performance and highly reliable conditions for water reuse in irrigation, indicating compliance with effluent discharge standards and stable operating conditions. Identifying seasonal variations in parameters promote the optimization of the operational conditions and performance of wastewater treatment plants.