1,721,020 research outputs found
Volatile fatty acids from sewage sludge by anaerobic membrane bioreactors: Lesson learned from two-year experiments with fouling analysis by the resistance in series model
Full text linkVolatile fatty acid (VFA) production from sewage sludge has become one of the main biotechnologies implemented in view of the circular economy application in wastewater treatment plant (WWTP) management. In this study, domestic sewage sludge collected from three WWTPs over two-year experiments was subjected to acidogenic fermentation. The fermented liquid was recovered through an ultrafiltration membrane. The membrane fouling was analysed in detail by applying the resistance in series model, revealing the major role of the extra polymeric substances in the reversible fouling, accounting for 91.2 % of the total resistance. Finally, the major contribution of the carbon footprint assessment was due to the indirect emissions (1.30 kg CO2eq/m3). The study has the novelty of providing an in-depth understanding of MBR membrane fouling used for solid/liquid separation in a plant aimed at VFA recovery from sewage sludge acidogenic fermentation. Also, the carbon footprint assessment provides insights regarding the environmental impact of VFA recovery through ultrafiltration membrane
Significance of integrated therapy of biological and physical cleaning for biofouling control and energy saving in AnMBRs
No full textKinetic Comparison of Attached and Suspended Biomass in an IFAS-MBR System Operated Under Intermittent Aeration: Long-Term Monitoring Under SRT Variation
No full textThis study presents a thorough investigation of a Membrane BioReactor – Integrated Fixed Film Activated Sludge – Intermittent Aeration (MBR-IFAS-IA) pilot plant operated from a biokinetic point of view. Specifically, respirometric techniques were applied on suspended and attached biomass to evaluate kinetic and stoichiometric parameters. The main aim was to investigate how the simultaneous presence of biofilm and activated sludge could affect the kinetic behaviour and the role of the Sludge Retention Time (SRT) variation in the kinetic behaviour of the system. The results highlighted a specialisation in the IFAS-MBR configuration, with the suspended biomass more affine to organic matter, whilst biofilm in the nitrification process. It was demonstrated that it is possible to operate IFAS-MBR systems at very low SRT without hampering the nitrification ability of the system due to the growth of nitrifiers in the biofilm, and the “seeding” effect would sustain nitrification even in the activated sludge. Respirometry has been confirmed to be an effective tool for evaluating biomass kinetic and stoichiometric parameters. The results of this study can be helpful in applying mathematical models in the design phase and for monitoring biomass viability during plant operations
Water reuse from wastewater: comparison between membrane bioreactor and ultrafiltration process
Full text linkThis study compares two different pilot plant configurations treating real wastewater to produce water for agricultural irrigation scope. The two configurations (Configuration I and II) operating in parallel have the same biological treatment unit. Specifically, the biological treatment occurs in an Integrated Fixed Film Activated Sludge – Intermittent Aeration (IFAS-IA) reactor. For Configuration I, the solid/liquid separation occurs through a membrane bioreactor (MBR). While, for configuration II a settler is devoted to the solid/liquid separation, followed by a tertiary ultrafiltration unit. During the plant operation, monitoring of the treatment performance coupled with the permeate quality according to the EU 741/2020 regulation was performed. Further, the nitrous oxide (N2O) emission has been measured, and the carbon footprint and the reclaimed water quality index (RWQI1) have been quantified. Results showed that Configuration I provided the best results in terms of both RWQI1 and carbon footprint. In terms of RWQ1, Configuration I provided 0.62 kg pollutant/year, while Configuration II was 0.43 kg pollutant/year. Regarding carbon footprint, the lowest value (0.38 gCO2eq/m3) was obtained from Configuration II due to the reduced membrane fouling
IFAS Intermittent Aeration Membrane Bioreactor System: The Influence of Sludge Retention Time
Full text linkThis study presents a comparative evaluation of a Membrane BioReactor – Integrated Fixed Film Activated Sludge – Intermittent Aeration (MBR-IFAS-IA) pilot plant operated under two different (Period I and Period II) sludge retention time (SRT) conditions. Specifically, the SRT was set to 7 and 3.5 days during Period I and II, respectively. The study has the main scope of investigating how lowering the SRT of the biofilm contributes to pollutant removal. During both experimental periods, total chemical oxygen demand (TCOD) removal was very high (97.8% on average). An improvement in orthophosphate (PO4-P) removal efficiency occurred during Period II (43.8%) compared to Period I (27.7%). However, a slight worsening in the removal efficiency performances was obtained during Period II, mainly for ammonia oxidation, total nitrogen (TN) and soluble (sCOD) removal. The reduction of SRT from Period I to Period II showed a substantial reduction of nitrous oxide emission (N2O) from 0.42% to 0.23% of the influent total nitroge
Improving Recovery of Valuable Bio-Products from Sewage Sludge Using Innovative Membrane Technologies
No full textMembrane bioreactor (MBR) technology has been employed in sewage sludge treatment within polyhydroxyalkanoate (PHA) production systems to tackle challenges like sustainable recovery of volatile fatty acids (VFA) and achieving high-quality effluent. Typically, MBRs utilize pressure-driven membranes, mainly ultrafiltration (UF) membranes. Despite its advantages, membrane fouling remains a significant hurdle, particularly when scaling up from laboratory-scale to pilot and full-scale plants. Living Membranes® (LM) offer a novel approach to self-forming dynamic membranes (SFDM), relying on the formation of a stable layer of sludge particles, organic compounds, and microorganisms between a cost-effective supporting materials. LM® reframes membrane fouling from a drawback to a key part of the treatment process. Being composed of organic materials, the encapsulated layer within LM® serves as both a carbon source and a nutrient trap, promoting microbial growth and ensuring high contaminant removal. This abstract presents insights from the application of pilot-scale ultrafiltration membrane bioreactor (UF-MBR) and Living Membrane® bioreactor (LMBR) for PHA production. The UF-MBR and LMBR technologies have been compared under both anaerobic conditions, aimed at VFA production via sewage sludge acidogenic fermentation, and aerobic conditions, mainly focused on the removal of contaminants. Preliminary results suggest that LM® offers a sustainable and efficient alternative to conventional UF membranes in sewage sludge treatment, potentially enhancing the recovery of valuable resources such as clean water, VFAs, and PHA
Super-hydrophilic and positive charged pressure retarded osmosis membrane for efficient ammonia recovery and energy production
No full textPressure retarded osmosis (PRO) is an emerging technology platform that harnesses the natural phenomenon of osmosis to address natural resources and energy scarcity. However, ammonia rejection and mechanical strength have been generally regarded as critical criteria. In this study, a new tailored, reinforced amine-rich pressure retarded osmosis (RaPRO) membrane is fabricated. The membrane support layer is strengthened by integrating it with tricot fabric, while the active layer is coated with polyethylenimine (PEI). The results indicate that RaPRO with 1% PEI coated under a polymerization time of 15 min creates a super-hydrophilic (contact angle –71°), low roughness (6.8 µm), and high positive charged (zeta potential –20 mV at pH 7) membrane. This new RaPRO membrane allows high water flux (33 LMH) and minimizes ammonia permeate (1.9 GMH at a feed concentration of 500 mg/L). In addition, osmotic power is generated at the remarkable value of 7 W/m2 under the optimal applied pressure of 10 bar. This is expected to support the fit-for-future system that facilitates efficient water, ammonia, and energy recovery
FORWARD OSMOSIS PROCESS FOR SECONDARY EFFLUENT AND SEAWATER APPLICATION.
Full text linkPh.DDOCTOR OF PHILOSOPH
APPLICATION OF MOVING BED MEMBRANE BIOREACTOR FOR TREATMENT OF DOMESTIC WASTEWATER
Full text linkPh.DDOCTOR OF PHILOSOPH
Modeling and Optimization of the Forward Osmosis Process - Parameters Selection, Flux Prediction and Process Applications
Full text linkPh.DDOCTOR OF PHILOSOPH
- …
