Moving bed biofilm reactor (MBBR) for dairy wastewater treatment

Abstract

The Moving Bed Biofilm Reactor (MBBR) system is considered an Advanced Wastewater Treatment (AWT), which combines the best of Conventional Activated Sludge (CAS) and biofilter processes, making use of suspended biomass and attached biomass. This system requires less space than CAS to process the same amount of wastewater and can be adapted to the existing structures of CAS. The dairy wastewater obtained during the milk transformation and cleaning operations is a residue characterized by a high content of organic matter and hydrocarbon compounds which contribute to its biodegradability, normally allowing the use of biological processes for the treatment of these effluents. In this study, the performance of the MBBR at a lab-scale during batch and continuous operations was addressed while changing the Organic Load (OL), the Filling Ratio (FR) and the Hydraulic Retention Time (HRT). The MBBR shows to be more stable when a FR of 40% is used, which allows a reduction of the HRT from 8 to 4 h, reaching a COD removal of 95%, allowing a reduction on the energy consumption, compared to the conventional processes.