Tag Archives: Membranes Bioreactor

Membrane Bioreactor

Membrane bioreactors are an advanced method of water filtration synergizing the membrane process, involving microfilters or similar devices and a system called a bioreactor. This filtration process is highly effective and is capable of filtering up to an approximate 50 million liters a day. This water may then be used for irrigation, placed back into the ocean in coastal areas, etc.
This process has a relatively small carbon footprint and it is easy to upgrade older wastewater treatment plants to accommodate membrane bioreactor systems. This makes it an ideal investment for municipalities or cities that cannot build new wastewater treatment plants, giving them the option to merely upgrade.
To further understand how this device or process works, an explanation of the two major parts. Firstly, the membrane process is essentially the mechanical separation of two substances with the aid of a membrane. This process is generally used for liquids and gases. A membrane bioreactor typically uses a type of membrane referred to as a “cross-flow” membrane.
Bioreactors are systems that support a biologically active environment. These systems or devices are manufactured to support such environments. This other half of the process is where the wastewater is held before the membrane filters the water. Bioreactors typically have a culture of microorganisms living inside these devices to aid in the water purification process. Over time, however, dead microorganisms and other insoluble debris decrease the efficiency of the membrane. This is due to the debris and/or particles and microorganisms building up over the membrane thus decreasing its porosity and thereby decreasing the amount of water allowed to pass.
The combination of these two elements constitutes a highly efficient and cost-effective water filtration system. To properly allow these two elements to work together, two configurations of this process are available.
The internal or submerged configuration has the filtration system directly inside the main bioreactor tank or it has the filtration system inside an adjacent tank. The biomass or wastewater is then pumped through the membrane. The membrane may be flat or tubular and it may also be a combination of both types. This type of configuration can include a backwash system to flush out solids that may clog up the membrane. For systems where the membrane is in a separate tank, the membranes must be taken out for a cleaning regimen that is specific to the manufacturer of the membranes.
The second type of configuration is the external or sidestream configuration. This configuration involves the installation of the filtration and reactor elements separate from one another. Typically these are in two different plant rooms. In this configuration the wastewater or biomass gets pumped through modules of membranes, typically in series. After passing through the membranes, the biomass is then pumped back into the reactor for a second pass. This process may go on for as many cycles as the plant operator wishes. This configuration also has the option of allowing the biomass to pass through a bank of modules in series. Cleaning for this type of configuration is more complex than the former. Aside from the regimen specified by the membrane manufacturer, a cleaning tank may be required for the maintenance of the membranes.