Comparison of the effect of up-flow and down-flow Cascade anaerobic bioreactors in industrial wastewater treatment of sugar factory

The present research is the result of laboratory studies related to the comparison of the effect of up- and down-flows in the treatment of artificial biological industrial wastewater (combination of water and molasses of sugar beet factory) using suspended-bed anaerobic reactors. The main purpose of this study is to compare the results of chemical oxygen demand (COD) removal efficiency in different conditions of organic loading in accordance with the type of flow in suspended-bed sequencing reactors containing plastic media, rock materials and activated carbon. For this purpose, three cylindrical pilots with a diameter of 200 mm and a height of 800 mm with a volume of 24 liters on a laboratory scale and made of Unplasticized PolyVinyl Chloride (UPVC) have been used. During the whole period of research, the discharge of sewage entering the reactor varied from 2 to 4 liters per hour and the retention time of the system varied from 18 to 36 hours. After the start-up period was passed and the COD removal efficiency remained constant, the highest efficiency of COD removal percentage in the up-flow with the maximum amount of hydraulic retention time equal to 36 hours and organic load equal to 4.51 kg COD/m3.d equal to 88% was recorded. Also, the highest efficiency of COD removal percentage in the down-flow with hydraulic retention time equal to 24 hours and organic load equal to 3.21 Kg COD/m3 .d equal to 78% was recorded.