Apart from photovoltaic, photobioreactors are the only known industrial system utilizing sunlight directly. Due to chemical properties of the so-called reaction centre (the photochemical core of the antenna), algae cannot use all the light irradiated. At the peak of solarisation, the sun emits up to 32 times more energy than required. By diluting the light, the irradiation will never be too high for ideal growth; in all other known systems probably damage (photoinhibition) occurs. Due to the intelligent construction of the ecoduna photobioreactor, the light path is narrow: all of the given sunlight can be used and all the algae will be all time in an optimal process range for growth.
The hanging gardens system itself is at the same time a micro-bubble column for carbon integration. Within reactor plates 6 metres high, a total absorption of CO2 by the algae is assured. No carbon dioxide will escape and all the energy needed for integration is utilized. Many systems are very inefficient, using only a small percentage of the CO2 inserted, the rest bursts at the surface. Therefore, ecoduna provides a system which allows the maximum integration of CO2, directly inserted into the reactor. Compared to other systems, hanging gardens is optimized to dispense all the CO2 into the panels. The major benefits of the total integration of carbon dioxide, besides the positive impact related to global warming issues, are the improved efficiency and a better control of algal growth. Other systems, like so called V-Reactors, waste up to 95 % of integrated CO2, losing the same percentage of energy for compression.
By integrating the nutritious CO2, the same energy used for carbon integration is also used to haul the whole medium throughout the entire system. This unique feature is established by asymmetric CO2 injection into the system. The introduced bubbles generate a laminar flow by gas lift effect, sufficient to ensure a turbulence flow, better mixing and even distribution of the cells to the light surface. At the same time, nutrients are well dispersed. With this technology, running costs are reduced by more than 80 % compared to other closed photobioreactors. Many other systems involve pumping with pressure or high acceleration. Since the ecoduna system can be operated by moving the medium through the reactor without pumping, it is superior to the outdated systems. They are either discontinuous or, like horizontal pipes, waste vast amounts of energy by pumping the media.
The ecoduna system is pressure less, to let excess oxygen dispose but closed to the ambient atmosphere and therefore allows regaining all the water. No evapotranspiration will occur, like in non-closed systems such as open ponds or V-Reactors. All of the water, except the amount metabolized into the carbohydrate production, is regained and recycled. This part of the liquid can be found in the protoplasts, the living content of the new cell wall. The rest of the culture medium undergoes water treatment. With adequate water treatment, all other living organisms of the culture media (bacteria, protozoa and fungi) are eliminated and the remaining valuable nutrient can be utilized again. This means, in general, that one has to replace only the nutrients used by the algae.
The tremendous loss of agricultural area by land erosion, building activities and due to biofuel production has put industrial biomass production under moral and ecological pressure - only the production of microalgae can counter that argument. By the sum of all betterments, the land required for an ecoduna algae production is only a fraction compared to other systems. Light-absorption is increased and the higher yield on minimum land required ensures a sustainable utilisation of land. Furthermore, the closed design of the reactor will allow algae biomass production in areas disadvantaged by climate, on fertile soil or areas short on water. Costs of infrastructure, land and energy for heating and cooling are important running cost issues; they are directly linked to photosynthetic efficiency and the size of the system. For bulk production from algae (i.e. energy, bio plastics, etc.), only the systems with maximum photoactive volume per m2 footprint will be competitive and sustainable – just like the photobioreactor of ecoduna!
In the ecoduna hanging gardens system, there is a significant decrease in the number of joints and sealing rings compared to a conventional horizontal tubular reactor (-75%). Every joint and seal ring is a risk factor for fungal or bacterial infection, especially in a highly efficient pure breed of micro algae. By reducing the number of these construction elements, the risk of bacterial contamination is diminished and incidences of infections become scarce and less dramatic. This is of high importance, because the so called biofilm (an extracellular matrix which contains sugar molecules, algae, fungi, protozoans and other materials) prevents a good algae growth and therefore a high yield. The treatment against this biological harassment is significantly minimized, requiring low doses of fungicides and antibacterial agents. In total, the ecoduna system is much less expensive compared to other systems, because of the lower use of antimicrobial agents.
The unique modular construction of the ecoduna photobioreactors allows customized applications for different kinds of production or research, making the ecoduna system very flexible. Once a hanging garden system has been built, it can be adopted without problems. The modular implementation of our system allows taking out a single module for service and letting the rest 95 % of media remaining under production without any effort. Therefore, the running risks are drastically reduced. This makes our photobioreactor very cost efficient and superior to other systems.
The ecoduna hanging gardens system is the only known system to have the cultivation in a fully continuous process. The expected yield is higher and the quality can increase drastically for being a real pure breed and all the cells had a chance to grow up to ripeness and accumulate sufficient lipids and properties. Nutrient input can be used more economically because they only need to be provided in the optimal amounts for the present stage of cultivation. Discontinuous systems or semi-continuous systems are operating at great operational risk of losing vast amounts produced by contamination of infection. An ideal photobioreactor enables a circulation of the solution and has a cross section which hinders photolimitation. In a hanging gardens reactor, the rising CO2 bubbles ensure that the entire solution and all cells are perpetually propelled to the photobioreactor's trophogenic zone.
To achieve the maximum output from an algae cultivating system, the most imported point is the photoactive volume. It is the most mistaken and misinterpreted issue in the algae-producing industry.
(Opend pond is an out-dated system, only feasible for consistent, moderate climatic conditions. All the calculations and publications are still based on the traditional way of algae farming from open ponds.)
If algae are breed in an open pond, the first few millimetres below the surface are the zone of light inhibition. From the irradiation of up to 80,000 lux, only 1,500 - 2,500 lux is utilisable for algae. In the zone close to the surface it is impossible to prevent damages on algae DNA or cell destruction if not shaded or filtered.
A severe decrease in quality results from dead and damaged cells in the cultivation.
Light-inhibition means that cells are damaged or stressed by an over lighting. The cells use up their own oil reserves to recover, or if dead, endanger the rest of the culture.
Only a small zone of approximately 20 millimetres is seen as the ideal growing zone.
In the zone below the photoactive area, there is very little photosynthesis activity because only a few light photons are not used or reflected by the cells above and reach deeper into the pond.
Open pond suppliers argue, by mixing the culture by a paddle-wheel to create a turbulent flow, all cells are provided with light. However, this argument falls far too short: most of the time the cells are still in the dark zone of photo limitation, plus some short time in the zone of dangerous photo inhibition. Needless to talk about the energy input necessary for moving the paddle-wheel.
Open ponds offer the algae only a fraction of the total time in the ideal process-window for photosynthesis. Therefore, it is very unproductive: 1 m2 open pond offers only 20 litres of photoactive volume, regardless how deep the pond is.
Horizontal pipe reactors and so-called V-Reactors are both the most used systems today. They still face, as a matter of principle from the photo efficiency point of view, they still face the same problems like open ponds.
Since they are static, the light is coming from one side with density much too high, causing light inhibition.
Only a small zone of approximately 20 millimetres is seen as the ideal growing zone in the pipe reactor too.
The far side is in permanent shade and it depends on the diameter, how dramatic the miss investment was.
Glass-pipes below 5 cm diameter are too expensive so there is a limited growth of approximately 50 tons/hectare with glass pipe reactors.
Calculation example: V-Reactor (diameter = 20 cm; total length = 2m)
Only 10 to 12 litres are seen as photo active in 1 reactor, the vast majority of the reactor is dark and unproductive from a certain cell density on. Light limitation will occur. It is impossible that are more than 2 reactors on 1 m2 footprint. Therefore, the maximum of productive volume is 20 to 24 litres / m2. If, a so called V reactor is compared to an ecoduna reactor, offering 440 litres photoactive volume / m2, the open pond must be 18 cheaper to be equal in costs. At this time, more disadvantages of V-Reactors like the 18 times higher energy costs for heating and cooling plus the costs of the greenhouse and land are not yet considered.
All organisms can be divided into two groups which are interdependent on each other and differentiated by the manner in which they incorporate carbon dioxide into their cell structures. Plants are able to take in sources of inorganic carbon dioxide, and are therefore autotrophic.
Humans are nourished by the organic carbon compounds produced by plants. They are already available in an energy-rich form and convert it to be used in the body. Therefore, we are simply dependent on the abilities of autotrophs.
The main features in industry are based on the same principle: carbon compounds from crude oil, natural gas and coal, all produced millions of years ago, are used as energy spenders. Recently industrialisation, with its wasteful attitude to fossil fuels, has caused a lot of economic, ecologic and social questions to be asked.
Massive betterments in yield and quality of the algae are subsequent to the fully continous process in ecoduna's system.
For an honest (and scientific) look at the productivity and the yield of algae production, we need to bear in mind the normal distribution of Gauss.
In its basic form, it prescribes that most of the algae – e.g. if we are focussing on the oil content - contain a wide range of oil, from
- zero or just a few per cent, to
- nearly 80 or even 90 %.
Most of the organisms contain a medium value, so it is wrong to calculate with top values as found in lots of overoptimistic pretences. The reason why we are committed to a fully continuous system with low to medium cell densities is, because we can control the conditions of our culture exactly and so get more cells into the stage of high oil content. The expected yield in discontinuous cultivation will be, according to the probable density function, only a fraction of the expected yield.
A continuous production can account for all the phases of algae and supply the required conditions plus ensure a yield, close to the maximum capacity.
Not only the cultivation of algae is possible with the help of ecoduna’s technology, also the production of ecoduna PBRs on an industrial scale is possible. This is also necessary to offer the PBRs at competitive prices. Some of the machineries used for assembling the PBR have been invented by ecoduna-staff, e.g. the laser-machine which is fixing plastic components automatically! It looks like science fiction, but it is only the high-tech production process at ecoduna in Austria!
Please update your Adobe Flash Plugin
Increased requirement for renewable fuels, raw materials, clean water or oxygen, create an opportunity for the large-scale cultivation of micro algae without the downside associated with traditional fossil fuels. Carbon dioxide and waste water containing nitrates can be used as cheap and readily available resources in biogenic industrialisation.
ecoduna's system creates viable conditions for the industrial expansion of micro algae breeding.
Intendi la ragione e non ti bisogna esperienza.
Know the reason and there is no need for experiments. (Leonardo da Vinci)
The world's actual status of a all-embracing, living organism demands for renewable fuels, raw materials, clean water oxygen and a clever way of reducing carbon-dioxide from the atmosphere. These requirements, which are increasing continously, create a great opportunity for the large-scale cultivation of microalgae without the downside associated with traditional fossil fuels. Carbondioxide and waste water contain nitrates and can be used as cheap and readily available resources in biogenic industrialisation.
Ecoduna's system creates viable conditions for the industrial expansion of micro algae breeding.
