Optimizing Aeration Cycles for Enhanced COD and BOD5 Removal in Domestic Wastewater Treatment: A Case Study from Al-Hilla City, Iraq

ABSTRACT Eutrophication is a risk factor because wastewater has an excessive amount of organic matter, specifically chemical oxygen demand (COD) and biological oxygen demand (BOD5), which deplete dissolved oxygen (DO) in water bodies. Since the biological treatment of wastewater is reliable, affordable, and produces safe results, it has been a valuable technique for treating wastewater for centuries. This work discusses the treatment of actual domestic wastewater from Al-Hilla city in Babylon using a laboratory-scale batch reactor with several input-characterized samples to forecast the elimination of COD and BOD5 together. Different cycle times were used 6, 8, and 12 hrs. The removal efficiency of organic matter (COD, BOD5) from wastewater increased when the aeration time (A) of cycles increased. The removal efficiency of organic matters (COD, BOD5) was increased when there was an increase in aerobic conditions (A) during the fill and react phases, because of the aerobic degradation of the incoming organic matters as a result of microorganism activity, where; the removal efficiency of COD ranged from (43.3-88.8), while for BOD5 was (58.8- 91.2).