{"id":21788,"date":"2025-02-28T16:09:14","date_gmt":"2025-02-28T15:09:14","guid":{"rendered":"https:\/\/aquaforest.eu\/?post_type=docs&p=21788"},"modified":"2025-12-03T10:55:41","modified_gmt":"2025-12-03T09:55:41","password":"","slug":"af130-media-reactor-as-mbbr-reactor","status":"publish","type":"docs","link":"https:\/\/aquaforest.eu\/en\/knowledge-base\/af130-media-reactor-as-mbbr-reactor\/","title":{"rendered":"AF130 Media Reactor as MBBR reactor | Resources | Blog about aquariums | Aquaforest"},"content":{"rendered":"\n
\"Freshwater<\/figure>\n\n\n\n

Types of Filtration in Freshwater Aquariums<\/h2>\n\n\n\n

The dominant filtration solution in freshwater aquariums consists of devices based on a static, submerged biological filter bed. Water flows through a stationary medium, typically made of ceramic elements or sponge. In smaller tanks, internal or hang-on-back filters are most commonly used. In contrast, canister filters are the preferred choice for medium-sized aquariums. Large tanks are more often equipped with custom filtration solutions.<\/p>\n\n\n\n

The Role of Microorganisms in Biological Filtration<\/h2>\n\n\n\n

The functioning of this type of filter is based on the microbiological activity of organisms living on the surface of the filtration medium. These microorganisms secrete a polysaccharide, gelatinous substance rich in enzymes that break down impurities. In addition to bacteria and fungi, this substance also harbors micro-predators that feed on them. This process creates a specific micro-ecosystem known as a biofilm.<\/p>\n\n\n\n

From the perspective of aquarium water purification, the biofilm that forms on solid submerged elements is far more significant than bacterioplankton (free-floating bacteria in the water column).<\/p>\n\n\n\n

Disadvantages of Static Biological Filter Beds<\/h2>\n\n\n\n

The static biological filter bed is undoubtedly a well-proven and effective solution. However, like any system, it has certain characteristics that may be considered suboptimal in specific circumstances.<\/p>\n\n\n\n

From the perspective of a process engineer or water technology specialist, the key characteristic of this type of filtration medium is the gradation of conditions within it. This occurs both along the water flow through the filter bed and as water penetrates into the interior of a porous element (such as a piece of ceramic). Water carrying impurities\u2014 which simultaneously serve as substrates for enzymatic reactions conducted by microorganisms\u2014 undergoes purification progressively as it flows through the filtration medium.<\/p>\n\n\n\n

This means that the availability of essential nutrients for microorganisms gradually decreases while the concentration of reaction byproducts (e.g., CO\u2082, NO\u2083\u207b, H\u207a) increases. Only in the first layer of the filter bed do conditions closely resemble those in the aquarium\u2014 with full availability of organic compounds, oxygen, and stable pH. A similar variation occurs as water penetrates deeper into porous elements.<\/p>\n\n\n\n

In reality, only the outermost layer of the filtration medium provides optimal conditions for aerobic decomposition of impurities. However, this does not mean that the rest of the filter bed is inactive\u2014 rather, the availability of substrates progressively declines. On the other hand, these changes create conditions more favorable for other types of microorganisms. For example, as oxygen levels decrease while nitrate concentrations rise (due to the activity of aerobic nitrifying bacteria), conditions become increasingly suitable for microorganisms capable of denitrification or nitrate respiration.<\/p>\n\n\n\n

The Impact of Nitrate Reduction in Different Aquarium Setups<\/h3>\n\n\n\n

This process ultimately leads to a reduction in nitrate (NO\u2083\u207b) concentration. In planted aquariums, it is common for the availability of nitrogen compounds, such as nitrates, to become a limiting factor for plant growth. To counter this, aquarists often supplement the tank with fertilizers containing nitrogen.<\/p>\n\n\n\n

In such aquariums, the nitrate-reducing effect of static biological filter beds may be considered suboptimal. However, in plant-free tanks, this feature is undoubtedly beneficial. It helps to maintain water quality by reducing excess nitrogen compounds.<\/p>\n\n\n\n

\"White<\/figure>\n\n\n\n

Alternative: Moving Bed Biofilm Reactor (MBBR)<\/h2>\n\n\n\n

An alternative solution, used for several decades in industrial applications and increasingly adopted in aquaristics, is the moving bed biofilm reactor<\/strong> (MBBR). In this system, microorganisms form a biofilm on the surface of specially designed plastic carriers. Inside the reactor, water is continuously mixed, causing the carriers to move freely throughout its volume.<\/p>\n\n\n\n

This movement ensures that all microorganisms have equal and consistent access to substrates, creating optimal conditions for aerobic decomposition of impurities<\/strong>. While processes like denitrification<\/strong> may still occur within the biofilm due to microenvironment variability, the conditions for such processes are significantly less favorable compared to static filter beds.<\/p>\n\n\n\n

The Biofilm Renewal Effect<\/h2>\n\n\n\n

Another fascinating feature of moving bed biofilm reactors (MBBR) is the constant renewal of the biofilm. The continuous movement and collisions of the plastic carriers cause gradual abrasion of the biofilm, which stimulates its regeneration.<\/p>\n\n\n\n

This is a crucial advantage. Decades of industrial experience with this technology have demonstrated that MBBR systems offer remarkable efficiency compared to traditional alternatives. The continuous rejuvenation of the biofilm not only enhances water purification efficiency but also boosts the system\u2019s adaptability.<\/p>\n\n\n\n

This means that both the species composition and the enzymatic activity of microorganisms (i.e., the type and quantity of enzymes secreted into the polysaccharide matrix) adjust more effectively and rapidly to the composition of pollutants entering the reactor.<\/p>\n\n\n\n

In simple terms<\/strong>: MBBR bioreactors have been able to break down substances that other microorganism-based filtration solutions could not handle.<\/p>\n\n\n\n

Additionally, their higher efficiency allows for the use of smaller bioreactors while maintaining the same level of water purification. Another key advantage is their greater resistance to toxic substances, thanks to their enhanced adaptability. The continuous renewal of the biofilm enables it to adjust rapidly to changing conditions, making MBBR systems more resilient and effective in fluctuating environments.<\/p>\n\n\n\n

Advantages of MBBR Reactor in Aquaristics<\/h2>\n\n\n\n

When using moving bed biofilm reactors in aquaristics, two additional benefits can be highlighted:<\/p>\n\n\n\n