There are various activated sludge methods in wastewater treatment though, membrane bioreactor method is one of activated sludge method where treated wastewater and activated sludge are separated by microfiltration membrane or ultrafiltration membrane in stead of conventional settled tank. It is often called MBR method or just MBR as well. Other than that, it is also called membrane activated sludge method.
|■ About Membrane bioreactor method (MBR method)|
In conventional activated sludge method, activated sludge are sometimes not separated enough with natural sedimentation and flew into treated wastewater (it is called carrying over) because of reasons like bulking (activated sludge to be floated easily), etc. Also, density of activated sludge which can be held in reaction tank tends to depend on ratio of natural sedimentation and size of final settling tank.
Therefore, membrane bioreactor process is developed as a technology to prevent carrying over of activated sludge by separating activated sludge from treated wastewater forcibly, together with miniaturizing reaction tanks by increasing density of activated sludge, and with excluding final settling tank including its postprocessing such as filtration by sand, disinfection, etc.
It is developed in the United States in the 1960s and spread over the world after the 1990s according to development of technologies about membrane.
MBR has been increasingly used at large-sized treatment plants worldwide, and movement toward standardization has also been accelerating in various countries. Therefore, we consider that MBR will become a core technology for use when reconstructing, upgrading, or enhancing medium- to large-scale treatment plants also in Japan.
Membrane bioreactor method separates treated wastewater and activated sludge with using membrane such as microfiltration membrane and ultrafiltration membrane, instead of using conventional settled tank.
・Facilities are smaller compared with conventional activated sludge method.
・Activated sludge does not flow into treated wastewater (no carrying over).
・Since treated wastewater passes through microfiltration membrane and ultrafiltration membrane, quality of the water is improved, filtration by sand can be excluded, and recycling of treated water is easy.
・Because large microorganism such as coliform bacteria can also be removed, disinfection of treated wastewater is not necessary when discharging into revers. However, there are some cases that disinfection is done for the purpose of preventing virus outflow.
・To prevent clogging of membrane (called Fouling), it needs to be cleaned regularly by chemicals such as hypochlorous acid or alkaline detergent.
・It depends on usages and materials though, membrane needs to be replaced regularly every 1-5 years.
・For aeration of membrane surface or circulation of activated sludge, and for vacuuming of treated wastewater, more energy such as electricity is required compared with conventional activated sludge method.
Water in the sludge thickened in the sludge thickener tank are removed at dehydration process to a certain degree.
However, moisture content is normally more than 80% and the sludge still has adhesiveness and stickiness. Also, latter processes are not easy because of influence of flocculants. Our drying apparatus of KENKI DRYER with international patented technology can surely dry any sticky, adhesive and viscus sludge, and also materials in liquid state like slurry, without clogging inside of the dryer. Also, because of its simple structure, its price is low and apparatus cost of the dryer can be retrieved by reducing industrial waste disposal cost within 3 years. Dried materials can be recycled as fuel, bacterial fertilizer, soil conditioner, etc. since component of the material is hardly changed because of its low-temperature drying method.
It can be applied to a system with pyrolysis apparatus as well.
|Please consider KENKI DRYER for drying of sticky materials, adhesive materials and materials in liquid state that no other dryer can deal with.|
|Initial, running and maintenance costs are low because of its simple structure based on internationally patented technology.|
|For sludge drying, costs of our dryers are estimated to be retrieved within 2, 3 years by reducing industrial waste disposal cost.|
|For raw material slurry drying, laborious works of manual operation will be decreased significantly by replacing box shaped compartment tray dryer with our dryer|
|In case of organic wastes drying, the waste can be recycled as fuel, fertilizer, soil conditioner and feedstuff after being dried.|
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