Application of alternative carriers without protected surface in moving bed biofilm reactor for domestic wastewater treatment

Abstract

Biological reactors with immobilized biomass on free carriers have provided new perspectives for wastewater treatment, once they reduce the system size and increase the treatment capacity. In this study, the performance of three Moving Bed Biofilm Reactors (MBBRs) using different carriers (with and without protected surface area) were evaluated for domestic wastewater treatment in continuous flow. Each MBBR (i.e., R1, R2, and R3) was filled at a ratio of 50% with high-density polyethylene (HDPE) carriers with different characteristics: both R1-K1 and R2-Corrugated tube with protected surface and R3-HDPE flakes without protected surface. Chemical oxygen demand (COD) removal of 80 + 5.0, 80 + 3.5, and 78 + 2.4% was achieved by R1, R2, and R3, respectively. The oxygen uptake by biofilm attached on the carriers was 0.0079 + 0.0013, 0.0033 + 0.0015, and 0.0031 + 0.0026 μg DO·mm2 for the K1, corrugated tube, and HDPE flakes, respectively. No significant differences were observed between the performance of the three MBBRs in terms of physico-chemical parameters (alkalinity, pH, and dissolved inorganic carbon) and COD removal. Results showed that the carrier type and its characteristics (total area and with/ without protected area) did not affect the organic matter removal. Thus, the carrier without a protected surface in MBBR could be a promising low-cost option for domestic wastewater treatment.