Environmental Applications of Algae

By Kris WalkerFeb 13 2013

Seaweed is one of the more complex types of Algae - Image Credit: Freeimage.com

Algae encompasses a large and varied group of autotrophic, photosynthetic organisms most of which have a very simple structure. They occur as single-cells, multi-cells or also as giant kelps. They are considered simple, as most do not have the same types of cells as found in land plants with the most complex being seaweed. Algae are made up of eukaryotic organisms and have a nucleus within a membrane and plastids enclosed in one or more membranes

Key Environmental Applications of Algae

Algae as a Biofuel

A number of government agencies and companies are funding efforts to minimize operating and capital costs and make algae fuel production commercially viable. Attempts are being made to cultivate algae into large amounts for making bioethanol, biodiesel, biogasoline, biobutanol, biomethanol and other biofuels.

Benefits of algal fuels are:

• They can be cultivated with minimal impact on fresh water resources
• Can be produced using waste and ocean water
• Are biodegradable and harmless to the environment even if spilled

Algae for Wastewater Treatment

The use of algae for wastewater treatment is more advantageous than conventional wastewater treatments. Some of the key benefits are:

• Economical – It is a cost-effective technique for the removal of phosphorus, nitrogen and pathogens when compared to sludge processes and other secondary treatment procedures.
• Low Energy Requirements – Conventional wastewater treatment processes involve aeration, which is energy intensive whereas, algae-based wastewater treatments produce oxygen that is needed for aerobic bacteria. Algae offers an efficient way for nutrient consumption and provide aerobic bacteria with oxygen through photosynthesis.
• Reductions in Sludge Formation – In traditional wastewater treatment facilities, the sludge obtained contains hazardous solid waste that finally finds its way to landfills. However, in algal wastewater treatment facilities, the resulting sludge with algal biomass has a large amount of energy that can be processed further to make fertilizers or biofuels. Algal technology does not use chemicals and the whole effluent treatment procedure is simple and results in minimum sludge formation.
• GHG Emission Reduction – According to the US EPA, conventional wastewater plants contribute significantly to greenhouse gases. Algae-based wastewater treatments release carbon dioxide but the consumption by algae is greater than what is released, making the whole system carbon negative.
• Production of Useful Algal Biomass – The algae biomass obtained is a source of biodiesel.

Photobioreactor or Algae Bioreactor

A photobioreactor or an algae bioreactor is used to cultivate algae to produce biomass or fix carbon dioxide emissions. Algae bioreactors are used for the production of fuels such as bioethanol and biodiesel for the reduction of pollutants such as CO₂ and NOx in flue gases emitted from power plants. These photoreactors are based on the photosynthetic reaction performed by algae containing chlorophyll. With the help of sunlight and dissolved carbon dioxide, CO₂ is made accessible by dispersing it into the reactor.

Other Eco-friendly Applications

Other major environmental applications of algae are:

• Algae can be used for trapping fertilizers present in farm runoff. After harvesting they can be used as fertilizer.
• Since algae can grow in harsh conditions and do not require many nutrients they are cultivated in places that are not suitable for agricultural purposes therefore, they do not compete for arable land as well as use wastewater, not freshwater.
• Unlike row crops, algae does not depend on specific seasons. Algae can thrive wherever there are warm temperatures and plenty of sunlight.
• Algae is grown in seawater as well as in desert ponds. Algae can also grow in waste water and water containing phosphates, nitrates and other contaminants.
• Since algae is carbon neutral, it can help the environment by taking CO₂ from the air. Algae farms can be located near carbon producing refineries or power plants.

Other Applications of Algae

Algae are used in a number of other applications that are enumerated below:

• Algae can be cultivated for hydrogen generation. In 1939, German researcher, Hans Griffon discovered that the algae, Chlamydomonas reinhardtii, could be switched from oxygen to hydrogen production.
• Algae is a complete protein containing important amino acids that are involved in metabolic processes such as enzyme and energy production. It has large amounts of complex and simple carbohydrates that provide the body with an additional fuel source. Specifically speaking, sulfated complex carbohydrates improve the regulatory response of the immune system. It also contains Omega 3 and Omega 6.
• Chondrus crispus or "carrageen"is a good stabilizer in milk products and reacts with casein, a milk protein that alginates in lotions and can be absorbed through the skin.
• Can be used as soil conditioners, fertilizers and as a livestock feed source. Since a number of species are microscopic and aquatic they are placed in ponds or clear tanks and harvested for the treatment of effluents pumped through ponds.
• Algae can also be used as sugar. Algae produce natural pigments that can be used instead of coloring agents and chemical dyes.
• Currently manufactured paper products are not easily recycled due to the chemical inks used. According to recyclers, algae inks are very easy to break down.
• The food sector is also attempting to replace the coloring agents presently used with coloring obtained from algal pigments.
• Algae can be used for medicine manufacture, sewage treatment and cosmetic manufacture.
• A green algae species grown in water tanks and exposed to sunlight and heat becomes bright red in color. This can be harvested and used as a natural pigment for foods such as Salmon.

Conclusion

Algae is highly beneficial in terms of its general usage as well as environmental applications. The days are not far away when we will live in buildings that will be beautifully enclosed in photosynthetic membranes and vertical gardens, harvesting solar energy, producing bioproducts and food for city dwellers. Imagine algae systems that recycles waste into fuel, animal food and bio-fertilizers.

Sources and Further Reading

• Uses of Algae as Energy source, Fertilizer, Food and Pollution control