1.1. How is the Organica solution different from the conventional activated sludge approach?

Organica FCR is a type of an fixed-film activated sludge system offering substantial benefits, both technical and economic, over alternative solutions. Like all IFAS systems, Organica FCR is based on the same activated sludge process that has been used in wastewater treatment for nearly a century, whereby micro-organisms and bacteria (collectively referred to as biomass) consume and metabolize or oxidize the contaminants available in wastewater.

Organica FCR drastically improves this process by leveraging a fixed-bed biofilm (attached growth, and not floating suspended in the water) that grows on both natural (plant) and engineered (patented biofiber media) root structures in a cascading reactor design, allowing a much greater quantity and diversity of organisms to thrive in the same physical space.

The larger and more diverse biomass per unit of reactor volume results in a significantly smaller physical footprint (reducing construction costs), as well as improved stability, increased nutrient removal performance, and reduced energy consumption.

Each Organica FCR is housed in an aesthetically-pleasing, odourless structure (greenhouse in colder climates, simple shading structures only in tropical climates) with the appearance of a botanical garden, preserving the surrounding land value and allowing the wastewater treatment plant (WWTP) to be placed directly adjacent to the wastewater source, thereby greatly reducing infrastructure costs.

Organica currently has more than 30 operating references, plus 20 or more under construction. With nearly two decades of experience utilizing root structures as a biofilm carrier, Organica offers proven, economic, and sustainable solutions for today’s wastewater management challenges.

1.2. When was the first Organica WWTP built?

The first Organica WWTP was completed and commissioned in 2001, designed for an industrial park in Budapest, Hungary, and currently treating wastewater for 3000 people (280 m3/day).

1.3. Are there limitations as to the size of the WWTP?

There are no size limitations to the solution. In fact, larger facilities see more pronounced economic benefits due to increased impacts of operational and construction cost savings. Further, thanks to its modular design construction can be phased according to the pace of increasing needs on site.

1.4. What is the largest Organica WWTP that has been built?

Today, the largest operating Organica WWTP treats up to 80 000 m3/day (500 000 PE). However, we have several projects under development and preliminary design that are over 250 000 m3/day.

1.5. Is Organica FCR suitable for upgrading existing treatment plants?

Absolutely – Organica FCR can be easily applied to upgrading outdated infrastructure, or meeting increasingly stringent discharge consent requirements. In fact, Organica has completed the upgrade of a WWTP project outside Budapest originally based on a conventional activated sludge solution, treating 80 000 m3/d (500 000 PE).

Upgrade projects are becoming more prevalent, as existing plants are struggling to cope with the demands of growing urban populations and changing regulations. FCR upgrades allow an existing plant to increase capacity and/or nutrient removal performance, commonly within the existing space and infrastructure. An upgrade with The Organica FCR will also have the same benefits and aesthetic appeal as a newly-built Organica facility while also reducing operating costs. In many cases, upgrades with the Organica solution also frees up valuable land, providing additional space for alternative development or other site requirements.

1.6. Why do you need the plants?

The use of natural (plant) and engineered (patented biofiber media) root structures as biofilm carriers enables the development and maintenance of 3 to 4 times the quantity of biomass per unit reactor volume when compared to other activated sludge-based solutions. The result is that Organica FCR removes the same quantity of contaminants/nutrients in half (or less) reactor volume, resulting in construction and equipment cost savings.

Further, plants naturally excrete organic acids, enzymes, and other compounds that allow the roots and biomass to operate in a symbiotic relationship, providing a natural habitat for a distinctive self-regulating ecosystems which include higher level organisms. Plants are the “ideal” media and are utilized as much as feasible in FCR designs. The resulting “food chain,” results in up to 35% less excess sludge compared to other activated sludge-based solutions, while also providing more complex organisms capable of breaking down complex contaminants in the wastewater (such as pharmaceutical and other difficult to remove compounds).

1.7. How well does the Organica FCR solution work in areas where contaminant loading conditions vary widely?

Through the use of root structures as a biofilm carrier in the Organica FCR, diversity of the microorganisms substantially increases (3000 species vs. 600-800 in Activated Sludge). This enhanced diversity creates a highly stable system that is able to adapt to unexpected fluctuations in the loading of the influent wastewater. Organica WWTPs are therefore well suited to locations that experience fluctuations in population, such as seasonal holiday resorts.

1.8. Can the system be built and operated in “decentralised” plans?

Absolutely – Organica WWTPs are specifically designed to be built and operated in a decentralised manner within urban landscapes.


2.1. Is the Organica FCR a “wetland”? Thus requiring extensive land area?

No – the Organica FCR is NOT a wetland. Wetlands are large earthen basins with plastic liners, filled with gravel or sand, and planted with reeds or similar plant species. They rely on an “unmanaged” process and have minimal technological components, with no ability to proactively change operational settings, and require large land areas.

In contrast, Organica FCR is a reactor-based solution. It uses natural processes, but in a highly-engineered environment, while requiring a much smaller surface area. The FCR is a complete treatment process, including solids removal, biological treatment, phase separation and tertiary treatment where required.

2.2. How clean is the treated water (effluent) from an Organica FCR?

The first design step in every case is to study the local conditions, including influent water characteristics and local regulatory discharge limits. Organica designs the treatment steps accordingly, using an industry-accepted process model and full-year dynamic simulation. Thanks to this design model, and the increased diversity and concentration of the biomass, the Organica Solution can meet the same effluent limits in less space and with less energy compared to conventional solutions.

2.3. Can the treated effluent be used as drinking water?

In very few countries around the world is direct potable reuse acceptable. More commonly, we see the reclaimed effluent used for irrigation, toilet flushing, or industrial/commercial applications such as cooling towers.

However, by adding further treatment such as RO filtration and further disinfection, our treated wastewater could meet drinking water standards.

2.4. How does this solution help the environment and solve water scarcity?

Organica’s FCR solution is ideal for producing treated water that meets the most stringent regulations for reuse. With a small footprint and attractive enclosure, the treatment facility can be placed near the wastewater source eliminating the need for extensive sewer networks (and associated pumping costs) and minimizing reuse infrastructure costs.

2.5. Is odour control incorporated into the design of the treatment plants?

The odorous elements of the treatment process are completely isolated, and are treated with odour scrubbers. As a result, the facility is a completely odour-free environment.

2.6. What happens until the plants mature?

Typical commissioning time of an Organica WWTP is around 3 months. During this period, sufficient surface area is available on the root structures (both natural and engineered) for sufficient biofilm growth to allow complete treatment, even if the plant root structure (under water) has not fully developed.

2.7. What role do the natural plant roots play in the treatment process?

The natural plant roots act as a biofilm carrier – a sort of “real estate” – for a much more diverse and robust ecology of organisms to grow and thrive in the reactors. The natural plant roots typically fill the upper 1-1.5 meters of the reactor space. Although the natural plant roots do not extend to the full depth of the reactors, they offer an incredible amount of surface in the space where they do grow (approximately 12,000 m2 of surface area per m3 of reactor volume which they cover). The natural plant roots are an ideal habitat for a robust biofilm to grow, providing nutrients and oxygen to the micro-organisms that take residence there. This ultimately results in a more active and less “dense” biofilm, improving diffusion of both air and nutrients into the deep layers of the biofilm.

2.8. Do the plants remove nutrients such as phosphorus (P) and nitrogen (N)?

The plants themselves do not treat the water: their primary function is to provide a habitat within their root zone for the microorganisms (biofilm) that treat the water. While the plants absorb some nutrients, it is negligible from a process sizing perspective.

2.9. Does the facility function differently during the winter?

At lower temperatures, biological reactions are slower therefore the biological treatment process is designed to ensure seamless operation in colder temperatures. This impact is similar to any other biological treatment process in the industry.

2.10. How sensitive is the process to hazardous chemicals and heavy metals?

The high biodiversity of the Organica treatment system makes it very resilient to shock loading. Organica facilities have shown higher resistance to sudden changes in influent than traditional alternatives. Cases in which it is known that there are industrial sources of wastewater with higher loads of contaminants often are designed with physical or chemical pre-treatment steps prior to the biological one.

In case of unsuspected poisoning event thanks to the high diversity to system re-establish faster than conventional counterparts would.

2.11. What happens if the plants die as a result of a disaster?

Organica provides plant maintenance training and manuals to the operator of the facility. If the instructions are followed, a “disaster” is highly unlikely. If this should happen, despite all careful plant care, re-commissioning the system would take approximately 30% less time than the initial commissioning.

2.12. How do Organica systems deal with ‘starvation periods’ or power outages?

The use of roots as a fixed-film carrier in a reactor-based environment is unique to Organica, and enables the formation of a complex ecology which results in highly efficient treatment characteristics. The highly evolved ecosystem (larger quantity as well as diversity of micro-organisms) in the reactors provides a high degree of operational stability. This allows smooth and uninterrupted operation of the facility even when fluctuations in the quality OR quantity of influent occur. Under low-loading conditions, the facility can run with 20% of its design capacity.

In the case of a power outage at the site, the reasons described above allow survival of micro-organisms in the reactors for an extended duration. Additionally, plants provide some oxygen and excrete small amounts of organic acids on their root surfaces which act as a food and oxygen source for the bio-film. Therefore, the plants help bacteria to survive the starvation periods in a power outage situation when the blowers are not functioning. For these reasons, in case of such an extreme event as a power outage, the biofilm can survive up to a week, even in an entirely shut-down facility.

2.13. What happens to excess sludge (WAS)?

Excess sludge (WAS) is treated in exactly the same manner as would be managed in a conventional process. First, the sludge is dewatered, and then it is usually shipped to a composting facility.

To differentiate, the presence of plants and the cascading reactor design provides a habitat for a distinctive self-regulating ecosystem which include “higher level” organisms. This results in the creation of a natural “food chain”, resulting in up to 35% less excess sludge compared to other activated sludge-based solutions.

If the facility is large enough – usually more than 200,000 PE – an anaerobic digester may be installed, generating biogas (methane) from the sludge. The energy produced from this can supply energy used to run the facility. If biogas production is a need, Organica can design the process accordingly and optimize the energy production potential of the sludge to be digested.

2.14. What happens to the snails and other higher-level organisms in the system?

When the higher-level organisms die, the resulting dead matter decomposes and is consumed by the microorganisms present in the system. This is the source of the “food chain” name.

2.15. What is the benefit of having snails, worms, and other higher-level organisms in the treatment plant?

Higher organisms have longer life cycles, allowing time for them to establish on the biofilm and develop of a complex ecosystem. These higher-level organisms consume matter, including some of the lower-level bacterium and also grow at much slower rates. The overall effects are less sludge produced. Additionally, the more complex ecosystem creates a more stable treatment process.

2.16. What is the hydraulic retention time in the system?

The hydraulic retention time is dependent on several parameters, including feed concentrations, discharge requirements, and water temperature. Typical process designs usually call for around 3-4 hours for a simple BOD removal plant. However, for plants requiring nutrient removal the retention time will be higher and above all the retention time is a factor of temperature, but obviously this varies for each design.

2.17. Is disinfection part of the treatment process?

In general, disinfection is part of the process of treating water to reuse quality, but this depends on local requirements.

2.18. Is the FCR solution suitable for treating industrial wastewater?

Organica’s FCR solution offers a wastewater treatment solution for any industry that generates a biodegradable waste stream, such as milk, cheese, meat, pulp and paper, breweries and slaughterhouses (but not limited to these sources), in a smaller footprint than traditional treatment solutions. Organica’s FCR solutions can be located close to the manufacturing facility, providing water for reuse in industrial processes and resulting in both infrastructure and operating cost savings.


3.1. How does the land requirement of an Organica facility compare to that of a traditional treatment system?

The combination of smaller reactor volumes, lower suspended solids, and creative architectural design results in land requirements up to 60% less than an activated sludge design for the same application. The smaller physical footprint results in significant land savings and reduced construction costs compared to alternative approaches

3.2. Is the greenhouse or shading structure difficult to build?

Both greenhouses (necessary in colder climates) and shading structures (suitable for warmer climates) are relatively inexpensive to build, and are already manufactured on a large scale for the agricultural industry. We commonly recommend greenhouses available “off the shelf” with all inbuilt functionalities for climate control (such as wind meter, thermometer, etc.).

3.3. Is it expensive to heat the greenhouse?

Heating requirement of the greenhouse is a function of the local climate. The aim is to ensure a minimum of 6-8°C inside of the greenhouse. The greenhouse effect and the biological processes undertaken in the FCR reactors generate heat, so minimal additional heating is needed.

3.4. What is the lifespan of the facility?

As with any treatment alternative, the lifespan of an Organica facility is a function of its maintenance. For example, the pumps, mixers and blowers need to be regularly checked and, if required, serviced. Replacement is needed approximately every six or seven years. General site maintenance should also take place on a regular basis. The plants regenerate themselves, and the biofiber media can last over 20 years without replacement.

Organica’s solution has its basis in natural processes and ecosystems that are self-perpetuating. As such, providing that the WWTP is well maintained, there is no predetermined end to its operational lifespan.

3.5. Is it more expensive to build than a traditional treatment plant?

No – Organica WWTPs are actually constructed at very similar total costs to conventional systems, particularly when considering capacities of 5000 m3/d and above.


4.1. How long does it take to build an Organica facility?

Facilities are typically built within six to nine months, depending upon the project size. The construction phase is followed by a testing and commissioning period (approximately 3 to 6 months). During this time the system stabilizes and can be optimized as needed.

4.2. What are the cordon sanitaire requirements?

Buffer zone requirements depends on the local regulations, however thanks to the odour-free and noiseless operation, in addition to the aesthetically appealing image of FCR designs, regulators often break down the cordon sanitaire to 50 meters or less.

4.3. Are Organica facilities smaller than alternative processes?

The combination of smaller reactor volumes, lower suspended solids, and creative architectural design results in land requirements up to 60% less than activated sludge designs for the same application. The smaller space requirement results in less land usage and reduced construction costs compared to alternative approaches.


5.1. What are the operational costs?

The overall operating cost (OPEX) of an Organica FCR is significantly less than other activated sludge-based systems, primarily due to reductions in both energy demand and sludge production.

Because of the solution relies on fixed-film cultures, and less on cultures suspended in the water, the water in the reactor has lower solids concentration and is “clearer”. Oxygen transfer in clearer water is more efficient, thus less air is required to be pumped into the reactor to meet oxygen demand. This results in lower power consumption, typically 20 – 50% lower than competitive designs.

Further, due to the multilevel food chains that are present in complex ecosystems, the bacteria that process waste material are consumed by other organisms, which are in turn prey for higher predators within the food chain. This food chain effect results in lower excess sludge (commonly 20 – 30% less) at the end of the treatment process.

5.2. How energy efficient is the system?

In FCR process, the vast majority of the biomass is fixed on the natural (plant) and engineered (patented biofiber media) root structures, resulting in low suspended solids throughout each stage of the treatment process. Further, the presence of the plants helps create a loose biofilm structure, allowing oxygen to penetrate into the deepest layers of the biofilm fixed on these root structures. This combination of “cleaner” water and the loose structure results in highly efficient oxygen transfer rates, thereby lowering aeration requirements, which is the most energy-intensive part of any aerobic treatment process. The result is typically a 20-50% reduction in electricity consumption compared to other activated sludge-based solutions

5.3. Can photovoltaic panels be installed on the roof of the greenhouse?

Yes. In order to ensure natural sunlight to reach the plants it is recommended that panels are installed on no more than 25% of the total roof area. Using photovoltaic panels on the site contributes to the overall energy efficiency of the WWTP.

5.4. How much excess sludge (WAS) is produced?

The presence of plants and the cascading reactor design provides a habitat for distinctive self-regulating ecosystems, including many higher-level organisms. The resulting creation of a natural “food chain” results in up to 35% less excess sludge compared to other activated sludge-based solutions.

5.5. What is the average MLSS (mixed liquor suspended solids) concentration?

In the FCR reactors the biomass is fixed to the root structures, rather than suspended in water. We therefore use the term ‘Equivalent Biomass Concentration’ (EBC) rather than MLSS. The EBC for an Organica system is 10-18kg/m3. By comparison the MLSS in an Activated Sludge plant is 2-5 kg/m3.

5.6. How frequently do the plants need to be replaced, and how much maintenance is involved?

Such as in the nature, plants renew themselves, replacement is rarely required. The natural presence of plentiful water & nutrients provides a reliable habitat for the plants to thrive. Further, non-invasive species are utilized to minimize maintenance- requiring only simple gardening skills. On average it amounts to about an hour a week for most small facilities. All information on plant maintenance is provided by Organica in the Operation Manual.

5.7. What happens to excess plant material? How much excess plant mass is produced?

The excess plant material is put into an onsite compost bin, and the compost is used in the garden area of the treatment plant. A 10,000 PE plant requires two compost bins.

5.8. How many staff are needed to operate the plant?

Organica supplies the Instrumentation and Control Package for every Organica FCR design. This helps ensure proper operation of the facility in spite of any construction quality issues, and also gives Organica the opportunity to access data remotely and provide Process Optimization Services to the operators once the facility is operational.

For process control, Organica supplies Siemens automation products with a custom library for Organica FCR designs. These tools provide the operator with an easy-to-use graphic interface..

Staffing requirements are usually determined by local regulation, taking into account health and safety factors.

5.9. Do storm conditions affect the efficiency of the system due to ‘wash through’?

The benefit of utilising a ‘fixed bio-film’ is protection from “wash-out” from hydraulic shock load conditions; therefore efficiency is maintained even after severe storms.

5.10. Does the Biomodule deteriorate over time?

Specifically designed to fit securely into concrete FCR reactors, the biomodule acts as the support mechanism for the biofilm carriers – both the natural (plant) and engineered (patented biofiber media) root structures – in an Organica FCR. Biomodules come pre-assembled with simple installation and operating instructions, making it easy for any EPC contractor to install them as part of the civil construction process.

The Biomodules are fabricated of stainless steel to avoid corrosion; additionally the biofiber media is resistant to the conditions in the wastewater.

5.11. What happens if a diffuser or any other mechanical equipment within the reactors requires replacement/maintenance?

Biomodules are designed for simple maintenance. The plants are not placed directly above the biofiber media, allowing visibility of the media throughout facility operation and enabling simple maintenance when equipment in the reactors (e.g. diffusers) requires replacement.

After emptying the reactor, with the help of a small portable crane, the operator can pull up the biofiber media like a curtain about 2 meters high and can access the bottom of the reactor.

5.12. How is the maintenance within the reactors affected by laws regarding confined space?

Operators carrying out maintenance within an Organica reactor would be subject to the same laws as they would be when working in reactors for other biological processes.