Performance evaluation of the pilot scale upflow anaerobic sludge blanket – Downflow hanging sponge system for natural rubber processing wastewater treatment in South Vietnam

Abstract A pilot-scale upflow anaerobic sludge blanket (UASB)–downflow hanging sponge system (DHS) combined with an anaerobic baffled reactor (ABR) and a settling tank (ST) was installed in a natural rubber processing factory in South Vietnam and its process performance was evaluated for 267 days. The UASB reactor achieved a total removal efficiency of 55.6 ± 16.6% for chemical oxygen demand (COD) and 77.8 ± 10.3% for biochemical oxygen demand (BOD) with an organic loading rate of 1.7 ± 0.6 kg-COD·m −3 ·day −1 . The final effluent of the proposed system had 140 ± 64 mg·L −1 of total COD, 31 ± 12 mg·L −1 of total BOD, and 58 ± 24 mg-N·L −1 of total nitrogen. The system could significantly reduce 92% of greenhouse gas emissions and 80% of hydraulic retention times compared with current treatment systems.