EPS and SMP dynamics at different heights of a submerged anaerobic membrane bioreactor (SAMBR)

Abstract

a b s t r a c tMembrane bioreactors (MBR) technology for wastewater offers many advantages over conventional technologies such as high effluent quality, less footprint and others. The main disadvantage of membrane bioreactors (MBR) is related to membrane fouling, which is mainly caused by extracellular polymeric substance (EPS) and soluble microbial products (SMP). This research studied EPS and SMP dynamics at different heights of a submerged anaerobic membrane bioreactor (SAMBR). The SAMBR was operated under two organic loading rates (OLR) (0.79 and 1.56 kg/m 3 d) and was fed with synthetic wastewater with glucose as the carbon source. The results showed percentages of chemical oxygen demand (COD) removal above 95% and the highest COD removal rates were observed at the bottom of the reactor (>83%) for both OLR. The EPS showed a stratification with highest quantities in the supernatant. For the SMP the highest concentration was in the bottom of SAMBR where utilization predominated associated products whereas in the SAMBR supernatant predominated biomass associated products. The OLR change led to a significant increase in SMP accumulation but not in EPS. These facts showed that EPS and SMP dynamic in the SAMBR seemed to be mainly influenced by biological activity, total suspended solids concentration and substrate composition.

Membrane Fouling Characteristics of a Side-Stream Tubular Anaerobic Membrane Bioreactor (AnMBR) Treating Domestic Wastewater

“…These bands are suggested to be related to carbonyl, amide I, and amide II structure, which indicated the proteins [57]. The peaks at 1375 cm −1 (C−N stretch) and 3417 cm −1 (N−H stretch) in the fouling layer are assigned to the primary and The influent peaks indicate two peaks in regions I and II which were suggested to be of protein-like substances associated with the aromatic amino acids and tryptophan, in agreement with the previous research [32], and the fluorescence peaks III and IV were related to the presence of fulvic and humic acid-like substances [50]. The AnMBR EEM peaks exhibited the high intensity of the peaks, two peaks, which are located around Ex/Em = 225-235/295-310 nm (Peak A) and Ex/Em = 225-235/330-350 nm (Peak B) as listed in Table 2 and Figure 5, these new peaks were identified from the EEM spectra of bound EPS, namely Ex/E = 310-330/370-400 nm (Peak D) associated with humic acid-like substances.…”

“…FT-IR (Nicolet 8700, Thermo Electron Corporation, Boston, MA, USA) with a resolution of 4 cm −1 within 400-4000 cm −1 was used to characterize the functional groups of organic matter present in the fouling layer and the cleaned and fouled membrane. SEM-EDS (SEM-EDS, SU-8020, Hitachi, Tokyo, Japan) analysis of the AnMBR concentrate and membrane fouling layer were performed to elucidate the structure and composition of organic and inorganic foulants [32]. To analyze the fouled and cleaned membrane with scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and fourier-transform infrared spectroscopy (FTIR), the fouled membrane was removed from the AnMBR setup and replaced with a new membrane.…”

“…The proteins dominated in both soluble microbial products and bound EPS ( Table 1). The EPS constituents has been reported as the main cause of membrane fouling [34], Luna et al [32] reported that the proteins have a hydrophobic tendency, while carbohydrates manifest a hydrophilic tendency. sodium found after alkaline solutions cleaning were residues of alkaline cleaning solutions.…”

Soluble microbial products (SMPs) in the effluent from a submerged anaerobic membrane bioreactor (SAMBR) under different HRTs and transient loading conditions

“…COD removal at HRTs (12 h, 8 h, 6 h and 4 h) was excellent (> 97%). The COD removal values are consistent with previous research in anaerobic membrane bioreactors[13][14][15]. Hu and Stuckey[13] operated a SAMBR with the lowest HRT at 3 h and still obtained very good performance (90% COD removal).Permeate COD was very low, and in the range of 12 -16 mg/L (HRT 12 h, 8 h, 6 h and…”

Performance evaluation and organic mass balance for treatment of high strength wastewater by anaerobic hybrid membrane bioreactor

“…14,29 This advocates the possibility of An-HMBR to generate more digested sludge compared to the conventional aerobic system by further degradation of organic matter in the reactor. 14 Increase in OLR concentration led to increasing VFA concentration as the HRT decreased, which can be attributed to F/M ratio, 30 which also increased with OLR concentration ( Table 3). The F/M ratio of the reactor at steady state conditions was 0.18, 0.28, 0.36, and 0.85 corresponding to 3, 2, 1, and 0.5 days HRT, respectively.…”