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Anaerobic membrane bioreactors (AnMBR) treating urban wastewater in mild climates (Bioresource Technology)

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"Anaerobic membrane bioreactors (AnMBR) treating urban wastewater in mild climates" was published in Bioresource Technology.

Abstract

Feasibility of an AnMBR demonstration plant treating urban wastewater (UWW) at temperatures around 25-30 °C was assessed during a 350-day experimental period. The plant was fed with the effluent from the pre-treatment of a full-scale municipal WWTP, characterized by high COD and sulfate concentrations. Biodegradability of the UWW reached values up to 87%, although a portion of the biodegradable COD was consumed by sulfate reducing organisms. Effluent COD remained below effluent discharge limits, achieving COD removals above 90%. System operation resulted in a reduction of sludge production of 36-58% compared to theoretical aerobic sludge productions. The membranes were operated at gross transmembrane fluxes above 20 LMH maintaining low membrane fouling propensities for more than 250 days without chemical cleaning requirements. Thus, the system resulted in net positive energy productions and GHG emissions around zero. The results obtained confirm the feasibility of UWW treatment in AnMBR under mild and warm climates.

 

Highlights

• An AnMBR demo-plant was operated during one year under mild climate conditions.

• Effluent COD remained below effluent discharge limits with COD removals above 90%. 

• Sludge production was 36-58% lower than theoretical aerobic sludge yield. 

• The membranes were operated at gross transmembrane fluxes above 20 LMH. 

• A positive net energy production and avoidance of GHG emissions were achieved.

 

Keywords

Anaerobic membrane bioreactor (AnMBR); industrial-scale membrane; demonstration plant; methane production urban wastewater (UWW); mild/warmer climate

PDMS membranes for feasible recovery of dissolved methane from AnMBR effluents (Journal of Membrane Science)

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"PDMS membranes for feasible recovery of dissolved methane from AnMBR effluents" was published in Journal of Membrane Science.

Abstract

This study aimed to evaluate the feasibility of degassing membrane (DM) technology for recovering dissolved methane from AnMBR effluents. For that purpose, a PDMS membrane module was operated for treating the effluent from an AnMBR prototype-plant, which treated urban wastewater (UWW) at ambient temperature. Different transmembrane pressures and liquid flow rates were applied for evaluating methane recovery efficiency. Maximum methane recoveries were achieved when increasing the vacuum pressure and reducing the liquid flow rate, reaching a maximum methane recovery efficiency of around 80% at a transmembrane pressure (TMP) of 0.8 bars and a treatment flow rate (QL) of 50 L h−1. The results revealed that the combination of PDMS DMs and AnMBR technology would allow to reduce the energy demand of UWW treatment, achieving net energy productions while reducing greenhouse gas emissions. Optimum operation was determined at a TMP of 0.8 bars and a QL of 150 L h−1 when combining energy, environmental and economic targets. Under these operating conditions, the combination AnMBR + DM resulted in energy requirements and greenhouse gases emissions of −0.040 kWh and 0.113 kg of CO2-eq per m3 of treated water, respectively, resulting in a DM payback period of around 10.5 years.

Highlights

• PDMS membranes allow a suitable methane capture from AnMBR effluents.

• AnMBR energy efficiency can be improved by employing PDMS membranes.

• Greener wastewater treatments can be reached by coupling PDMS membranes with AnMBR.

• PDMS membranes showed a feasible potential for full-scale applications.

Keywords

Anaerobic membrane bioreactor (AnMBR); Greenhouse gas (GHG); Methane recovery; PDMS degassing Membrane; Urban wastewater.

8 November, 2018. EurEau Annual Congress Limassol (Limassol, Cyprus)

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EurEau Annual Congress Limassol where was presented the Life Memory Project: “Boosting circular economy in sewage treatment”.

23 September, 2018. 1st Workshop of the 11th International Conference on Urban Drainage Modeling (Palermo, Italy)

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1st Workshop of the 11th International Conference on Urban Drainage Modeling where was presented the Life Memory Project: “State-of-the-art MBR-based technology for anaerobic wastewater treatment: Identifying key issues for AnMBR modelling”.

16 - 21 September, 2018. IWA World Water Congress & Exhibition (Tokyo, Japan)

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IWA World Water Congress & Exhibition where was presented the Life Memory Project: “AnMBR Technology: Boosting circular economy in sewage treatment”.

9 - 13 July, 2018. Euromembrane 2018 (Valencia, Spain)

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Euromembrane 2018 where was presented the Life Memory Project in the Oral presentation titled: “Optimising membrane performance for anaerobic urban wastewater treatment”.