Treatment capacity of a novel flexible fibre biofilm bioreactor treating high-strength milk processing wastewater

Abstract

This study was focused on the capacity investigation of a novel multistage flexible fiber biofilm reactor (MS-FFBR) to treat milk processing wastewater (MPW) with high organic loading (OLR). The MS-FFBR performance was evaluated at four intermediate stages separately and also the final effluent quality of the overall system with an influent chemical oxygen demand (COD in ) ranged from 1500±20 to 6000±50 mg/L and hydraulic retention times (HRTs) of 8, 12, 16 h. By comparting the bioreactors into the four stages effectively enhanced the bioreactor's performance. The maximum TCOD removal efficiency was achieved at the first stage, which was about 89±20, 82±20 and 78±20 % at HRTs of 16, 12, 8 h, and low COD in of 1600±20, 1590±20, and 1673±20 mg/L, respectively. However, the first stage had less contribution to TCOD removal at high COD in concentrations, reported to be about 42±4 %, 46±4 %, and 25±4 % at COD in of 5960±40, 5830±40, and 5870±40 mg/L, respectively. Furthermore, the MS-FFBR was effective in removing total suspended solids (TSS) and turbidity. The bioreactor has reduced the effluent turbidity to 9.0±0.2, 20.0±0.6 and 16.1±0.5 NTU at low COD in concentrations of 1600±20, 1590±20, and 1670±20 mg/L and HRTs of 16, 12 and 8 h, respectively. The bioreactor revealed a high COD removal rate increased from 2.3±0.1 to 12.2±0.4 kg TCOD/m 3 d by increasing the OLR from 2.4±0.1 to 17.6±0.4 kg TCOD/m 3 d, confirming high reactor capacity for treatment of high strength wastewater. Kinetic studies confirmed that the biomass yield was low at various HRTs ranging 0.1-0.2 gVSS/gCOD.

Effect of Different Operational Conditions on the Treatment Performance of Milk Processing Wastewater (MPW) Using a Single Stage Flexible Fibre Biofilm Reactor (SS-FFBR)

“…In another study, the maximum TCOD removal efficiency was obtained at an HRT of 12 h and COD in of 1590 mg/L [ 10 ]. The authors demonstrated that the increase in COD in led to the reduction in contribution of consecutive stages in TCOD removal efficiency [ 11 ]. In another study, effluent turbidity of 1 NTU was reported at HRTs of 4 and 8 h [ 3 ].…”

“…In this sense, Yu et al developed FFBR into a two-stage flexible fibre biofilm reactor to treat food processing wastewater [ 9 ]. Total chemical oxygen demand (COD) removal efficiency was 97% at COD in of 2700 mg/L with an organic loading rate (OLR) of 7.7 kg/m 3 d. With the inspiration from this work, we designed an innovative sequencing batch flexible fibre biofilm reactor (SB-FFBR), flexible fibre biofilm bioreactor, and multistage flexible fibre biofilm reactor to remediate raw milk processing wastewater [ 10 , 11 , 12 , 13 ]. The COD and TSS removal efficiencies were reported to be 92.5% and 89.1%, respectively, showing the high performance of the biofilm reactor.…”