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ARTICLES >> Livestock Articles

Is Algae the Key to De-Risking Food Supply?

Posted by Bestprac on Feb 02 2012

By Jane Garrett, Gascoyne Bestprac Group Facilitator
Road Trip, May 2010

 

In May 2010, the WA Bestprac Group held its Climate Change Forum at Monkey Mia Dolphin Resort. Helen Scott and Brian Ruddle from Biolectric gave a presentation about the production of algae from large, shallow ponds of circulating low grade water. At the time, their process was still an experiment at their facility in Bibra Lake, Perth, however now full-scale algae ponds are installed and running at their proof-of-concept site at Perenjori at the heart of WA’s wildflower country. Helen, her husband Wally (to her right), and Brian can be seen giving their presentation in the photo below:

 

 

 

 

 

 


On 8th April, some of WA Bestprac’s group members and a diverse group of interested people made up of farmers from the Perenjori area, government officials from Mid-West development commission, representatives from the department of agriculture, agricultural consultants, aquaculture and marine academics and representatives of the Perenjori shire visited the newly installed ponds.

The company Biolectric is committed to achieving compatibility between economic development and maintenance of the environment. The company emerged out of a research joint venture between Curtin University of Technology, CSIRO and an industry leader in transformer diagnostics. Initially, the company formulated environmentally friendly, renewable oil for the transformer market but other opportunities that assist to achieve reductions in carbon emissions economically were identified as that research progressed; one of the outcomes has been research into the production of algae. The pond had been functioning for approximately a week before the road trip and the entire self-sustaining set up, is shown in the photo below left:



 

 

 

 




The set up is entirely self-sustaining. Wind turbines and solar panels provide the electrical power. In the foreground is the Algae pond which measures is 50m long by 10m wide and is only 300mm deep. It contains 70,000L of water and was ‘seeded’ with 300L of algae approximately 4 days before this photo was taken; there had been clear growth and the first harvest was due around 12th April, approximately 1 week after the first seeding. A motor powered by a solar panel drives the paddle wheel that circulates the water and algae in the pond (at night algae does not grow so lack of water circulation in the pond overnight is not an issue). Algae grow in sunlight, although they do not like direct sunlight, and require a source of CO2 to maximise their growth rate. At Perenjori, this was to be provided from the waste of a nearby aquaculture fish farm, which is yet to be installed, so biodigesters (the orange ‘blob’ on the left of this photo, below) were installed to provide CO2 and nutrients.



 

 

 

 

 



Organic waste matter (manure, vegetable waste) is fed into the digesters through open tubes (that look like ears). The digesters themselves are spherical and are half buried in the ground to keep the contents at a constant temperature. The waste matter decomposes and its by-products are biogas (stored in the orange plastic bag behind the digesters) and liquid fertiliser. The liquid fertiliser becomes an added nutrient for the soil to aid crop, plant and algae growth. To the right of the digesters are 3 cylinders that extract, convert and hold the gas, which is then fed into a container providing the biogas power source. The biogas a fuel may utilised for heating and lighting and, in fact, has been a major source of fuel for rural homes in China and India for a number of years. 1 cubic metre of biogas produces 6 ½ kw hours of energy. 100kg of waste produces 60kg output, fertiliser liquid and biogas. The ratio of gasses produced (methane and CO2) depends on the temperature of the waste produce so containers are buried to make the temperature more stable.

The following diagram helps to explain how the biodigesters work:

So with solar power and its own CO2 production, the entire system at Perenjori is self-sufficient and capable of producing algae for animal feed.

Research has shown that algae fed animals have higher Omega 3 content, which translates into food; in eggs, milks and meat, which in turn means a healthier human diet. Algae biomass is a good source of protein, up to 34% raw protein in some strains of algae.

Whilst animals cannot be fed a 100% algae diet, a Queensland study has shown that algae fed animals burp less and have a 15-20% quicker growth rate. A study in Bangaldesh by Chowdhury, Huque and Khatun (‘Algae in Animal Production’) where test groups of animals were allowed to drink ‘algae water’ supported this fact and stated, ‘It appears that as a supplement to a straw diet, algal suspension somehow created a more favorable environment in the rumen for efficient microbial growth and thus increased nutrients availability to the host.’

Harvested biomass can be dried or made into paste and fed to animals but needs to be mixed with other elements to be a ‘total food source’. In the paper mentioned above, the animals had algae introduced into their water supply and this represents a very simple method of getting algae into the diet. 0.6g of algae per 1 litre of water is suggested. Dried algae can be stored as a biscuit, it can rolled out and made into flakes or it may be possible to spray it onto stubble to improve the taste of ‘cardboard’. Algae grows rapidly and large algae ponds can produce 40-100 tonnes of algae/hectare/year or 14,000 tonnes of dry algae/hectare/year of dry algae.

Algae ponds can have a natural (claypan if it is stable), concrete or lined base. Growth of algae does not require arable land and the ponds can be set up simply and at low cost. The pond below was constructed in just 3 days. 



 

 

 

 





The photo below shows a very simple excavated area, ready to be lined and Brian imparting more gems of information.



 

 

 

 




Algae in the ponds at Perenjori are a hardy, diverse WA culture rather than a monoculture that has undergone 2 years of testing in the laboratory and smaller scale trial ponds. Extracting a culture from a local region and mixing it with this tried and tested, resilient algae was a key part of the process to ensure successful algae growth in newly set up ponds. The water for the ponds came from a nearby dam; top up water will come from a bore that is about to be installed at the Perenjori facility.

As algae are microscopic, here’s Tim Higham gazing at the sample prepared by Brian Ruddell:


 

 

 

 




The algae in the ponds are WA algae which is tough, resilient to PH and temperature changes, although can be damaged by high temperatures. Testing has thus far shown that the particular strain of algae survived 55o temperature and has also survived freezing, however its growth was slowed dramatically. Optimum temperature for maximum growth is 33-34o with 20-35o the outer limits. At 15-18o the growth rate slows. Water salinity is a key factor that affects growth.

The algae at Perenjori are freshwater algae (not marine) and testing has so far shown survival at a salt content of 1.25% salt content (1/3 the concentration of sea water). This is an issue for the rangelands, where there is a high salt content in the water; algae for that region must be a saline tolerant strain. Open ponds are naturally subject to water evaporation and potential contamination from herbicides. As such, this is an area that still needs testing. Contamination on rangeland properties is certainly not an issue, however maintenance of water levels and salinity is. Ponds can be covered, but this, in turn, reduces the amount of sunlight, which is essential for algae growth. Methods of filling and topping up the algae ponds with water from solar paneled desalination plants were discussed.

Harvesting algae is an area that needs further investigation and experimentation. A centrifuge (the most expensive part of a very inexpensive system) has been tried. Flocculation will also be tested. A very small centrifuge copes with the single pond that has been installed. It’s the square blue thing on the table under the covered area in the photo below (note its small size!).

 

 

 





 


In terms of set up, the biodigesters took only 2 days to construct; the ponds took 4 days total (2 people to dig and the liner, which is a 2 man job). For busy farmers, automation of running the ponds is a key issue. There is also a need to obtain exact information on the breakdown of the algae constituents (protein, carbs, oil etc.) before it can be fed to livestock. There will need to be some experimentation on feeding the algae to animals. However, there was serious interest in algae as a nutritious food source.

There is also keen interest from the WA group to find funding to run some feeding trials. Whilst we seek to find ways to reduce our carbon footprint, as well as providing a food source, it must be remembered that algae sequester carbon at a rate of 1g algae to 2g of CO2 or 0.3g of algae sequesters cubic metre of CO2, so algae might not only be an answer to feeding during drought, it might also provide an alternative stream of revenue once we really have sorted out carbon credit trading.

For more information on algae ponds please contact Helen Scott.
For more information on the WA Bestprac group please contact Jane Garrett.
 

 VIEW the PHOTO GALLERY

Last changed: Feb 06 2012

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