Search Results (2)

The issue of environmental pollution caused by wastewater discharge from fruit juice production has attracted increasing attention. However, the cost-effectiveness of conventional treatment technology remains insufficient. In this study, a gravity-driven membrane bioreactor (GDMBR) was developed to treat real fruit juice wastewater from secondary sedimentation at pressures ranging from 0.01 to 0.04 MPa without requiring backwashing or chemical cleaning, with the aim of investigating flux development and contaminant removal under low-energy conditions. The results demonstrate an initial decrease in flux followed by stabilization during long-term filtration. Moreover, the stabilized flux level achieved with the GDMBR at pressures of 0.01 and 0.02 MPa was observed to surpass that obtained at 0.04 MPa, ranging from 4 to 4.5 L/m⁻² h⁻¹. The stability of flux was positively associated with the low membrane fouling resistance observed in the GDMBR system. Additionally, the GDMBR system provided remarkable efficiencies in removing the chemical oxygen demand (COD), biological oxygen demand (BOD), ammonia (NH₄⁺-N), and total nitrogen (TN), with average removal rates of 82%, 80%, 83%, and 79%, respectively. The high biological activity and microbial community diversity within the sludge and biofilm are expected to enhance its biodegradation potential, thereby contributing to the efficient removal of contaminants. Notably, a portion of total phosphorus (TP) can be effectively retained in the reactor, which highlighted the promising application of the GDMBR process for actual fruit juice wastewater based on these findings. Full article

Despite numerous studies undertaken to define the development and significance of the dynamic membrane (DM) formed on some coarse materials, the optimization of reactor configuration and the control of the membrane fouling of anaerobic dynamic membrane bioreactor (AnDMBR) need to be further investigated. The aim of this study was to design a novel anaerobic gravity-driven dynamic membrane bioreactor (AnGDMBR) for the effective and low-cost treatment of municipal wastewater. An 800 mesh nylon net was determined as the optimal support material based on its less irreversible fouling and higher effluent quality by the dead-end filtration experiments. During the continuous operation period of 44 days, the reactor performance, DM filtration behavior and microbial characteristics were studied and compared with the results of recent studies. AnGDMBR had a higher removal rate of chemical oxygen demand (COD) of 85.45 ± 7.06%. Photometric analysis integrating with three-dimensional excitation–emission matrix fluorescence spectra showed that the DM effectively intercepted organics (46.34 ± 16.50%, 75.24 ± 17.35%, and 66.39 ± 17.66% for COD, polysaccharides, and proteins). The addition of suspended carriers effectively removed the DM layer by mechanical scouring, and the growth rate of transmembrane pressure (TMP) and the decreasing rate of flux were reduced from 18.7 to 4.7 Pa/h and 0.07 to 0.01 L/(m²·h²), respectively. However, a dense and thin morphological structure of the DM layer was still observed in the end of reactor operation and plenty of filamentous microorganisms (i.e., SJA-15 and Anaerolineaceae) and the acidogens (i.e., Aeromonadaceae) predominated in the DM layer, which was also embedded in the membrane pore and led to severe irreversible fouling. In summary, the novel AnGDMBR has a superior performance (higher organic removal and lower fouling rates), which provides useful information on the configuration and operation of AnDMBRs for municipal wastewater treatment. Full article