Since its invention at the start of the 18th Century, biological wastewater treatment technologies have been emerged as the most economical and sustainable wastewater management tools for the treatment of wastewater containing organic/inorganic biodegradable pollutants in it.
Present biological wastewater treatment technologies are based on natural “self purification” process utilized by nature for the biochemical conversion of pollutants to less harmful forms. This process utilizes naturally occurring microorganisms under different environmental conditions for the breakdown of pollutants present in the wastewater.
Principally biological wastewater treatment technologies are categorized as suspended growth and attached growth processes based on mechanism of retaining microorganisms within the reactors. Further these processes are also classified as Aerobic and Anaerobic processes based on presence and absence of oxygen for the microbial degradation of pollutants.
Over the years, these basic process configurations have been evolved a lot to meet specific treatment requirements and many hybrid process configurations combining both suspended and attached growth processes have been developed and implemented for a wide range of wastewater treatment requirement within industrial and municipal segment.
Levapor is engaged in providing biological wastewater treatment technology based on innovative hybrid attached growth processes like MBBR(Moving Bed Bio Reactor) and IFAS (Integrated Fixed Film Activated Sludge) for Aerobic as well as Anaerobic treatment.
Through our investigative and R&D based approach, over the past few decades, we have developed various innovative, application specific process configurations utilizing biological processes to their maximum efficiency.
Our MBBR and IFAS technologies have been continuously refined through inhouse research to cater any challenging biological wastewater treatment requirement. Our primary focus is to deliver robust, sustainable, economical and efficient solutions to the clients for their needs.
MBBR And IFAS Attached Growth Process
Fixed film or attached growth processes have been in use for biological wastewater treatment since late 1800s.
In the attached growth process micro-organisms responsible for organics (BOD, COD) and nutrient (Ammonia,
TKN) reduction from wastewater are allowed to grow on specific support medium or carrier material which
provides habitat in the form of surface for the growth of microorganisms on it.
Though attached growth processes have same metabolic pathways for pollutant reduction as compared to
attached growth activated sludge process, they provides distinct advantages over suspended growth activated
IFAS (Integrated Fixed Film Activated Sludge): A Truly Hybrid Process
Conventionally with floating attached growth process, MBBR (Moving Bed Bio Reactor) configuration is a popular
choice. In MBBR no sludge recycle is practiced and all reduction is obtained via biomass attached on the media.
However, over the past few decades, IFAS (Integrated Fixed Film Activated Sludge) process is gaining momentum
due to its hybrid configuration and specific benefits the process provides to the wastewater treatment plants.
IFAS process with textile sheets, cord media and other fixed in place media has been around the scene quite for
a long time and has been successfully applied for the upgradation of existing overloaded activated sludge plants.
Though originally developed for the upgradation of existing activated sludge plants, the hybrid process
configuration can be applied for the new plants as well.
MBBR process is based on attached growth microbial communities growing as biofilm on specially designed
MBBR media. These microbial communities developed on MBBR media are playing major role in the biochemical
oxidation of pollutants present in the wastewater as BOD, COD and Ammonia Nitrogen. Because of this reason
MBBR media having properties which allows efficient and optimum growth of these biofilms are of prime
importance for any MBBR and IFAS based attached growth process for biological wastewater treatment.
Since the invention of MBBR technology, the development of MBBR media has been focused solely on utilizing
various plastic materials like Poly Propylene (PP), High Density Polyethylene (HDPE), Low Density Polyethylene
(LDPE) and other suitable plastic materials. By and large plastic MBBR media have cylindrical or circular shape
providing varying levels of surface area for biofilm development on it.
The primary assumption of this development is based on the hypothesis that more surface area provides more
biofilms which eventually results in more reduction efficiency and higher process economy.
However, it has been observed with these plastic MBBR media that biofilms grow on the inner void surface
while the biomass from outer surface area of the MBBR media is sloughed due to various reasons. To account
this phenomenon, specific surface area (SSA) and protected surface area (PSA) per m3 volume of MBBR media
provided are extensively used to estimate the efficacy of plastic material based MBBR Media. At present
different plastic MBBR media having different shapes and size are offering SSA of 500-4000 m2/m3.
However total surface area or protected surface area alone can not be taken as sole measure of MBBR media
efficiency for its better efficiency. Apart from surface area other important properties such as media surface
material, its texture, porosity, geometry, orientation of media plays crucial role. These properties greatly affect
the MBBR process design and efficiency to a greater extent.
Ideal MBBR/ IFAS Carrier Properties
|Ideal MBBR Carrier Properties||Benefits / Key Attributes to MBBR Process|
|Hydrophilic surface of material and density||Faster Wetting of carriers resulting in better fluidization and homogenization of fluidized bed. Hydrophilic nature of surface improves water binding ability of the carrier and thus helps maintaining bioactivity. better mass transfer of substrates across the biofilm segments.|
|High Inner Porosity and Fine Pore/Viod Structure||Faster colonization during the initial bioprocess start up, protection of biomass against toxic shock loads, better diffusion gradients leading to development of a diverse community strcture and composition based on the substrate gradient, growth of specific type of slow growing bacteria.|
|Surface Roughness and Adsorbing Capacity||Development of highly active biofilms with better access to bulk liquid, good mass transfer resulting in better reaction kinetics and thus removal rates, protection against toxic substances.|
LEVAPOR: An Ideal MBBR/IFAS Carrier
Levapor carriers are the first synthetically modified MBBR/IFAS carriers developed after considering the above
properties of ideal carriers for MBBR/IFAS process requirement
1. Levapor MBBR material is used in various applications due to its unique properties. It is made of reticulated Poly Ether based PU Foam that is impregnated with activated carbon.
2. The individual cubes of Levapor MBBR media measures 20 * 20 * 7 mm in size.
3. The weight of Levapor media is approximately 25 kg per cubic meter dry weight.
4. One of the key advantages of Levapor MBBR media is its large surface area, which is greater than 20,000 square meters per cubic meter. This extensive surface area allows for efficient contact between the media and the surrounding environment.
5. Levapor MBBR media has a specific gravity of 1.1 grams per cubic centimeter, indicating its density compared to water. Due to specific gravity slightly higher than water, the media gets fluidized much better compared to plastic media which has specific gravity of 0.95 – 0.98.
6. With more than 90% inner porosity, Levapor media has highly open and interconnected structure that enables the flow of fluids and gases much better than other MBBR carriers.
7. Due to its higher specific surface area and adsorption capacity, Levapor media requires only 10 – 15% degree of filling compared to 25 – 40% required for plastic.
8. The full fluidization energy of Levapor media is in the range of 4-7 Nm3 per square meter per hour of air. This value represents the amount of energy required to fluidize the Levapor media in a given system.
9. During the wetting period, it takes approximately 1-3 days for Levapor media to get completely wet and become part of liquid.
10. Levapor MBBR media demonstrates quick colonization, with a typical time frame of 60-90 minutes. This means that microorganisms can rapidly establish themselves on the Levapor media surface.
In summary, Levapor MBBR media is a versatile material with reticulated Poly Ether based PU Foam impregnated with activated carbon. It has a high surface area, excellent porosity, and quick colonization capability. These properties make Levapor suitable for biological wastewater treatment.
Advantages Of Levapor
Due to very high amount of area for the colonization of active biomass on it, compared to conventional plastic
MBBR carrier elements, Levapor carriers require only 10-15 % reactor filling to achieve efficient and reliable
process efficiency. The lower degree of filling allows for better movement of carriers as required for optimum
mixing and mass transfer within the aerobic biological reactor.
One Carrier, Many Process Configurations
Due to versatility of utilizing Levapor carriers with hybrid process configuration of IFAS, virtually , the carrier can
be agglomerated into any process configuration based on suspended growth technology including SBR, Step
Feed, Barden-Pho Process , RBC, Plug Flow Type Activated Sludge process and many more.