Tubular photobioreactors made from polyethylene "sleeves" have been described in a number of articles (e.g. Cohen & Arad, 1989; Merchuk et al, 2000), and used commercially (Olaizola, 2000). A generic design for a polymer film reactor is given in Tredici et al (1998). LDPE film is widely used as a greenhouse covering (Hussain & Hamid, 2004), which application has the same requirements as a photobioreactor: high visible light and near infra red transmission, low UV transmission, and low cost. Variants of the basic LDPE polymer which are also used as greenhouse films include LDPE/EVA (ethyl-vinyl acetate) copolymers and LDPE/LLDPE (linear LDPE). The main disadvantage of any of these materials is their short lifespan: even with the addition of UV stabilizers the maximum life of LDPE greenhouse film used as a greenhouse covering is 3 years (Hussain & Hamid, 2004). Research is currently being carried out at ANU (Australian National University) into the usable lifetime of LDPE photobioreactors. Here we use the value of 3 years, which is considered appropriate as the thermal cycling amplitude is lower for a photobioreactor material than a greenhouse covering, as it is limited by the culture thermal mass. Trials have shown that standard 180 μm greenhouse film is suitable as a photobioreactor material. 

Systems using LDPE film and glass tubular photobioreactors have comparable NER (net energy ratio) values, so the choice of material must be based on other criteria. The use of glass tubes and Clear acrylic tubing requires many more connection fittings as lengths of more than a few meters are not produced or, otherwise, are difficult to transport and assemble. Glass tubes and Clear acrylic tubing also require a supporting structure. The high number of fittings and supporting structures for the glass and Clear acrylic photobioreactor would reduce the NER values. Conversely, film tubes are produced as rolls of hundreds of meters in length and can be placed directly on a simply prepared and leveled surface. Larger diameter tubes have a lower mixing energy input, and can be readily manufactured in LDPE without an excessive increase in thickness (although attention must be paid to the maximum head pressure).

Source: Australian National University -Canberra, Australia

AlgaeTube™

Low Cost Algae Production Systems
Fully computerized and PC controlled  

Flowchart of an algae production plant

The AlgaeTube™- photo-bioreactor has many advantages. It is a unique, scalable, affordable and easy to install saltwater and freshwater algae growing system. The system is equipped with fully automated monitoring and control systems and includes feeding systems, pumps, sensors and series of clear, high transparent polyethylene tubes, called AlgaeTubes™. For optimal use the AlgaeTubes™ have a diameter of 320 mm Ø and a thickness of 200 to 300 micron. 

Today’s photo-bioreactors are made out of costly glass or Clear acrylic tubes and mounted in horizontal or vertical arrangements in many different shapes and sizes. All these systems depend on frames or structures to support the photo-bioreactor enclosures. As a result, all these different tailor made components result in high installation- and O & M costs for large-volume applications. AlgaeTubes™ however are laid out parallel in lengths ranging from 30 meter up to 500 meters . At the ends they are connected with specially constructed PVC corner connectors. These come equipped with sensors and feeding-connection points. Through these points CO2 and nutrients are injected and oxygen is relieved fully automated, computer controlled.

The whole system, including the algae growth, is monitored by computer and controlled with special, by AlgaeLink developed, software. It monitors algae density, nutrients, CO2, light, temperature, etcetera. The AlgaeTube™ system is sturdy and protected with UV inhibitors to assure a long life in any climate and comes with a 10 year factory warranty.

To create a solid subsoil underneath the AlgaeTube™, specially treated and UV stabilized polypropylene may be rolled out and laid down, at the same time preventing any weed growth. Each AlgaeTube™ bed has been designed to allow standard tractors and other farm equipment to prepare the fields and install the system. The underlying land not only supports the AlgaeTube™ system, but may also supply some thermal management control, depending upon installation.

The AlgaeTube™ system can be installed in substantially less time and operated at considerably less cost than competing systems.

When you are satisfied with the AlgaeTube™ production plant you have, and the results confirm that you have a very profitable business. You can stay with the AlgaeTubes, or we can offer the flexibility to change your AlgaeTubes™  for PC - Polycarbonate tubes (picture below), you can do this at any time without major changes to your existing system. 

Cost and specs of a
1 Ton/day dry algae system

(Larger systems are available)

Data below is based on growing the algae Nannochloropsis and will change when growing an other algae specie