15.3 Membrane processes for resource recovery from wastewater

Membrane processes are revolutionizing resource recovery from wastewater. These innovative techniques extract valuable nutrients, energy, and metals, turning waste into useful products. It's a game-changer for sustainability.

From phosphorus to biogas, membrane tech is making wastewater treatment more efficient and eco-friendly. This approach not only cleans water but also creates new revenue streams, aligning with circular economy principles.

Nutrient and Energy Recovery

Nutrient Recovery Processes

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  Frontiers | Plant and pathogen nutrient acquisition strategies View original

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  Frontiers | Recovery of Nutrients From Wastewaters Using Microalgae View original

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  A comparative study of microbial dynamics and phosphorus removal for a two side-stream ... View original

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  Frontiers | Plant and pathogen nutrient acquisition strategies View original

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  Frontiers | Recovery of Nutrients From Wastewaters Using Microalgae View original

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Top images from around the web for Nutrient Recovery Processes

• 

  Frontiers | Plant and pathogen nutrient acquisition strategies View original

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• 

  Frontiers | Recovery of Nutrients From Wastewaters Using Microalgae View original

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• 

  A comparative study of microbial dynamics and phosphorus removal for a two side-stream ... View original

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• 

  Frontiers | Plant and pathogen nutrient acquisition strategies View original

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  Frontiers | Recovery of Nutrients From Wastewaters Using Microalgae View original

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• Nutrient recovery involves extracting valuable nutrients like phosphorus and ammonia from wastewater using membrane processes
• Phosphorus recovery can be achieved through struvite precipitation, where phosphate ions are combined with ammonium and magnesium ions to form struvite crystals (MgNH4PO4·6H2O) that can be used as a slow-release fertilizer
• Ammonia recovery from wastewater is possible using membrane contactors, which allow for the selective transport of ammonia across a hydrophobic membrane, enabling its concentration and subsequent recovery as a valuable resource for fertilizer production or industrial applications
• Membrane-based nutrient recovery processes offer advantages such as high selectivity, low energy consumption, and the ability to produce concentrated nutrient streams suitable for further use

Energy Recovery through Biogas Production

• Energy recovery from wastewater can be achieved through the production of biogas, which is a mixture of methane and carbon dioxide generated during anaerobic digestion of organic matter
• Membrane bioreactors (MBRs) can be used to enhance biogas production by providing a high-quality effluent with low suspended solids, enabling more efficient anaerobic digestion downstream
• Anaerobic membrane bioreactors (AnMBRs) combine membrane filtration with anaerobic digestion, allowing for simultaneous wastewater treatment and biogas production in a single unit
• Biogas produced from wastewater can be used as a renewable energy source for heat and electricity generation, reducing the overall energy footprint of wastewater treatment plants

Valuable Resource Recovery

Recovery of Valuable Metals

• Valuable metals such as gold, silver, and platinum can be recovered from industrial wastewater streams using membrane processes
• Membrane filtration techniques, such as ultrafiltration and nanofiltration, can be employed to concentrate and separate valuable metals from wastewater, enabling their recovery and reuse
• Membrane-based metal recovery processes offer advantages over conventional methods, such as lower chemical consumption, higher selectivity, and the ability to handle large volumes of wastewater efficiently
• Examples of industries where valuable metal recovery from wastewater is applicable include electronics manufacturing, electroplating, and precious metal refining

Forward Osmosis for Resource Concentration

• Forward osmosis (FO) is an emerging membrane technology that utilizes the natural osmotic pressure gradient to concentrate valuable resources in wastewater
• In FO, a semi-permeable membrane separates a feed solution (wastewater) and a draw solution with a higher osmotic pressure, causing water to flow from the feed to the draw side, concentrating the valuable resources in the feed
• FO can be used to concentrate a wide range of resources, such as nutrients (phosphorus and nitrogen), valuable metals, and organic compounds, facilitating their subsequent recovery and reuse
• Advantages of FO for resource concentration include low energy consumption, minimal membrane fouling, and the ability to handle high-salinity wastewater streams

Membrane Bioreactors for Resource Recovery

• Membrane bioreactors (MBRs) combine biological treatment with membrane filtration, offering opportunities for resource recovery in addition to wastewater treatment
• MBRs can be designed to promote the growth of specific microbial communities that facilitate the recovery of valuable resources, such as bioplastics (polyhydroxyalkanoates) or single-cell proteins
• Extractive MBRs (EMBRs) incorporate a selective extraction process, such as liquid-liquid extraction or adsorption, within the bioreactor to recover target resources from the mixed liquor
• Examples of resources that can be recovered using MBRs include volatile fatty acids, enzymes, and biopolymers, which have various applications in the chemical, pharmaceutical, and food industries