UASB reactor startup for the treatment of municipal wastewater followed by advanced oxidation process

Abstract

The present study was done to shorten the start-up time of up-flow anaerobic sludge blanket (UASB) reactor. Two different nutrients were used during the UASB start-up period, which was designed to decrease the hydraulic retention time (HRT) from 48 to 24 and 12 to 6 hrs at average temperatures of 25-34°C. In the first stage, start-up was with glucose for 14 days and then the reactor was also fed with macro- and micronutrients as a synthetic nutrient influent (SNI) from 15 to 45 days as the second stage. For the control, a second reactor was kept on glucose feeding from day 1 to 45. The removal efficiencies of the chemical oxygen demand (COD) were 80% and 98% on the 6thand 32ndday of the first and second stage, respectively. The maximum substrate removal rate of 0.08 mg COD mg-1VSS d-1was observed for glucose and synthetic nutrient influent (SNI) on the 8thand 40thdays, respectively. When the reactor reached the maximum COD removal efficiency it was then shifted to municipal wastewater (MWW) mixed with industrial wastewater. The HRT was reduced gradually with a one week gap while treating MWW. For further cleaning, the UASB effluent was treated with 40% waste hydrogen peroxide. The whole integrated treatment process was successful to reduce the COD by 99%, total suspended solids (TSS) by 73%, total nitrogen (TN) by 84% and turbidity by 67%.