COD And Suspended Solid Removal By Anaerobic Baffled Reactor: A Case Study Of Domestic Wastewater From Van Lang University, Ho Chi Minh, Vietnam

Abstract

Experiments were carried out using 3 anaerobic baffle reactors (ABR) that have the same size. The reactors were made of glass with thickness of 5 mm, divided into five compartments. The first compartment has double volume compared to the remaining compartments. Dimension of the first compartment is 15 cm x 10 cm x 38 cm (width x length x height - inner face of tank), while the second compartment to the fifth compartment sized 15 cm x 5 cm x 38 cm. The study was divided into 2 periods. In the period 1, hydraulic retention time of the reactors were controlled in the range of 3-5 hours (ABR 1 – HRT 3h, ABR 2 – HRT 4h, ABR 3 – HRT 5h). In the period 2, the reactors of period 1 were continued operating with hydraulic retention time in the range of 1-3 hours (ABR 1’ - HRT 1h, ABR 2’ – HRT 2h, ABR 3’ - HRT 3h). Sludge concentration maintained in the range of 2,888-3,172 mg/L. Domestic wastewater was taken at catch holes of the Van Lang University which had suspended solids (SS) concentration in the range of 80-290 mg/L and total COD of 176-352 mg/L. After the operation has obtained positive results, effectively remove organic material in domestic wastewater achieve 72-74% with effluent COD reached 64-80 mg/L, SS removal efficiency achieved 89-99% corresponding to SS output of 2-25 mg/L and the optimal HRT 4-5 hours. When increasing organic loading rater (OLR) by reducing the hydraulic retention time in all reactors by 2 hours (ABR 1’ - 1h with OLR from 4.61 to 8.06 kg COD/m3.d, ABR 2’ - 2h with OLR from 2.30 to 4.03 kg COD/m3.d, ABR 3’ – 3h with OLR from 1.54 to 2.69 kg COD/m3.d), sludge concentration remains 2,968-3,172 mg VSS/L, after 15 days of operation, effectively removing organic matter best achieve 71-76% with COD decreased from 336 mg/L to 80-96 mg/L with HRT of 3 h.