PROJECT DESCRIPTION
BACKGROUND
The Canary Islands is the region in Europe that causes most pollution through CO2 emissions (3-4 Tm CO2/pers/year). This is mainly due to, their massive consumption of energy generated by oil fired power stations,(in the Canary Islands there is no gas) which fuel their desalinization plants and produce much of the island´s drinking water. Although there are a large number of waste water treatment centers, (WTP´s) none use a tertiary system due to the high costs of traditional technologies. Moreover the methane which is generated in the WTPs, cannot be used (it is burnt in situ) because the Canary Islands have not developed a system for channelling gas. The project therefore grew out of the need to investigate new ways of reusing urban wastewater and combustion gases and to promote a change in attitude towards the reuse of water as an important resource for the community. Since the 1960’s pioneer projects in the States have demonstrated the viability of using microalgae cultivation in waste water treatment, as an alternative system for reducing the levels of nitrogen (ammonia, nitrates and nitrites) phosphates and heavy metals in waste water. This process has proven effective in both enabling the reuse of water, in promoting an oxygenation process, whilst at the same time generating a new product: algae with a high nutritional value ( 50-70% protein) which can be used in animal feeds, particularly important in the Canary Islands where there is a shortage of fodder, and in the extraction of pigments and antioxidant substances. The Microalgae also acts as a bio filtering element of CO2 as it is incorporated into the biomass by photosynthesis. However, the technology for this process is still in an experimental phase and is encountering key difficulties around the selection of algae species adapted to the conditions of intensive cultivation and other problems. The project therefore set out to test new solutions to some of these problems in an industrial context.
OBJECTIVES
The project aimed to demonstrate, on a pilot scale (1 000m²), the efficacy and profitability of a micro-algae cultivation unit as a model for a new ecological agro-industrial system. Through this process the project hoped to encourage the creation of new enterprises which would cultivate algae on an industrial scale as a means of reusing waste water and the methane gases from the combustion process. This system was to be based on the re-utilization and biofiltration of waste provided by two industrial processes: a) The use of CO2 emissions from the combustion process from power stations and methane generated from the Waste Water Treatment Plants (WTP) and, b) waste water from urban sewers. The biomass of the algae generated by this system would be commercialized either as a supplement for hydrolyzed protein cattle fodder or for the extraction of pigments, poly-unsaturated fatty acids and other metabolites. The Biologa project also aimed to demonstrate that methane gas generated by the WTPs could be used both as a source of energy for the algae unit, and as a source of CO2 (the main nutrient in an algae cultivation system) to be injected into the cultivation tanks, thereby increasing the economic viability of the plants.
RESULTS
The project ran into delays both due to initial problems over securing an adequate site and over the failure by the company responsible for the algae cultivation plant to meet its deadlines However, the beneficiaries committed themselves to complete and operate the installations within the following year. Despite its delay problems the project clearly showed a commitment to deliver a state of the art example of new biotechnologies being used to create viable agro-industrial businesses capable of helping to solve two connected environmental problems: shortage of drinking water and the need to reduce CO2 emissions. The project succeeded in its objectives to fine-tune the methodology for use of microalgae in the reuse of waste water and combustion gases. These can be summarized in 5 key stages: Firstly, Algae Isolation and cultivation: microalgae, which had been selected for their biofiltering qualities were grown under controlled conditions (temperature, irradiation and photosynthesis) adapting laboratory systems to intensive “raceway” industrial systems. By April 1998, the project had succeeded in isolating and growing 12 different ecotypes of microalgae from different sources of waste water, showing a very good intensive culture growth. Secondly, Analytic control of water: by March 1999 the project had completed the study of the nutritional requirements of the water as a culture medium and standardized the concentration of salts. Thirdly, The Carbonation Process: during 2000 the project carried out the studies on combustion gases generated from the burning of both propane/methane and fuel oil, injecting them automatically by diffusion into the water supply. The multiple gas source was necessary to demonstrate the effectiveness of the system of biofiltration on gases with a very different profile and polluting impact.. The use of CO2 from propane combustion gases, as an alternative to traditional carbonation processes substituted the high costs of pure CO2 systems. Thirdly, the setting up and running of the Central Control System for growing and processing the biomass. The produced biomass achieved had an acceptable quality in terms of its chemical composition and health microbiology criteria. This was followed by the Final Production Process: the studies indicated that the processing phase would need to involve homogenization and pasteurization to guarantee its use as fodder. The algae powder obtained would have to be immediately protected from oxidation by vacuum packing. The project proved that the obtained product would have an improved microbiological quality and could also be revalued employing extraction processes to purify the poly-unsaturated organic acids and some pigments like carotenes and fycobiliproteins, which are currently in high demand commercially. The project took a high profile from the beginning on publicizing and disseminating results. This was partly done through the media: newspaper and magazine articles, radio and television programs and partly through the organization of site visits, conferences, seminars and meetings, and the creation of a permanent exhibition with information panels and the presentation of scientific posters. etc. The project also established a web site: www.bioalga.itc.org and developed a video.
