AnMBR
- 1. Technology Description
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AnMBR technology is the marriage of anaerobic biological treatment and physical membrane separation.
The main elements of the AnMBR system are the anaerobic bioreactor and membrane tank where ultrafiltration (UF)
membranes are located and solid/liquid separation occurs. The anaerobic process involves multiple steps
of disintegration, hydrolysis, fermentation, and methanogenesis resulting in conversion of BOD and organic
carbon to energy-rich biogas containing methane and carbon dioxide.
The physical separation process is UF that serves to: (1) maintain a high mixed liquor volatile suspended solids (MLVSS)
concentration in the bioreactor tank and (2) produce a solids-free permeate. Hollow fiber UF membranes
exclude solid particles larger than 0.04 microns, including most pathogens and large molecular weight organics,
resulting in a high permeate (filtrate water) quality. Generally two methods of membrane cleaning
are available ? sparging with biogas and scouring with fluidized GAC. The gas-sparged AnMBR will be demonstrated at Fort Riley, Kansas.
The GAC-fluidized AnMBR being developed by team member Dr. Perry McCarty and collaborators will be demonstrated
in parallel by Inha University in South Korea. In addition to removal of carbonaceous BOD by the AnMBR,
downstream processes including hollow-fiber gas-liquid contactors for dissolved methane recovery,
ferric chloride coagulation of sulfide and phosphorus, and regenerable clinoptilolite ion exchange
of ammonia are used to produce a high quality effluent suitable for re-use or disposal to surface water.
- 2. Benefits
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AnMBR is a low-energy, low-footprint, and scalable technology for treating domestic wastewater.
This treated water will meet secondary treatment standards and many water reuse standards and can be used for irrigation.
Sludge production by the AnMBR process is also significantly less than aerobic treatment processes,
which will reduce the logistical burden associated with sludge disposal or further processing for beneficial use of the residual biosolids.
An additional benefit includes less demand on public wastewater treatment plants, and thus greater security.
Potential savings of the AnMBR are estimated to be at least $5 million per year for the DoD,
resulting from lower energy requirements and sludge production.
Technical benefits of the AnMBR process include:
· energy-neutral technology for wastewater treatment,
· low sludge production with increased dewaterability,
· dissolved methane recovery to maximize energy recovery and minimize greenhouse gas emissions,
· low-energy nutrient removal/recovery processes that are compatible with the AnMBR process,
· expansion of the highly successful aerobic membrane bioreactor (MBR) platform that is widely
implemented around the world and is currently scheduled for demonstration at Fort Riley for sewer mining, and
· applicability to more than 50% of wastewater treatment plants in the continental United States based on temperature of domestic wastewater.