CROATIAN CENTER of RENEWABLE ENERGY SOURCES
Algae, the Source of Biofuels, and Aquaponics
Algae can be used as important types of biomass materials from which the biofuels can be obtained. Algae absorb the energy from the sun in the presence of carbon dioxide and store it. A number of processes can be carried out on algae to convert it into biofuels like alcohol, biodiesel and even biogas. The biodiesel obtained from algae can be mixed with petroleum diesel and it can be used for running of trucks, cars and many types of engines that use diesel. Biodiesel can also be used as the fuel in the jets, airplanes, refineries and pipelines. The biomass obtained from algae can be used as the renewable sources of energy since it is available in abundant quantities and will be available for unlimited period of time.
One of the important advantages of algae is that it can grow in any type of water like salt, fresh, and even contaminated water. It can be grown in vast sea and river water, small rain water ponds and even commercial or domestic manmade made ponds. Algae has the potential to yield 30 times more energy than the crops grown on land, which are currently being used to produce the biofuels. This could encourage the use of algae for producing biofuels instead of the land that can be used for producing food crops. The harvesting cycle of algae is 1 to 10 days, which permits several harvests in short period of time and using the resources more effectively.
Algae and Aquaponics
As described earlier, algae can be grown in any type of water and in type of water storage system. Besides the naturally occurring seas, rivers, and ponds, it can also grow in manmade ponds. The manmade ponds can be at homes for domestic purpose or in large lands made for commercial production of algae. For the better growth of algae some nutrients may be added to water. Besides using these ponds for algae growth they can also be used for the growth of fishes and other aquatic animals.
Aquaponics is the system where one can grow the fishes and plants like algae in one integrated system. The waste given by the fishes act as important nutrients for the plants, while the cover of plants provides the natural filter for the fishes in the living areas. Aquaponics is the combination of words aquaculture and hydroponics. Aquaculture is the cultivation of fish or other water based animals, while hydroponics is the growth of plants in water. In aquaponics one can grow the water animals as well the plants at the same time. Thus the manmade small or big pond can be effectively used for growing fishes as well plants like algae.
The plants usually prefer warm-water so the water in aquaponics is also warm. The fishes grown in aquaponics are of warm-water type and not of cold-water type. The fishes grown in aquaponics can be consumed by the owner, they can be given to the friend, can be sold in the market to earn money or they can be kept as the pets. The harvesting period of fishes ranges from 7 to 9 months. When aquaponics is combined with a controlled environment greenhouse, high quality crops can be grown throughout the year and in any part of the world.
Aquaponics comprises of the water tank where the fishes are raised and fed. There is a chamber, where the uneaten foods and other particles and solids are collected. The bio-filter converts ammonia into nitrates, which act as the nutrients for the plants. There is also a portion for the growth of the plants. The lowest part of tank is a sump from where fresh water is supplied to the tank and old water is removed.
The concept of aquaponics can be extended for the growth of algae. Instead of the plants, one can grow algae, which has the harvest cycle of one to ten days. At the same time the fishes can also be grown. In the period of about nine months, while the fishes will harvest once, algae will be harvested several times. The large quantities of algae collected this way can be used as the biomass for producing the biofuels like biodiesel.
The advantages of using aquaponics for the growth of algae is that in a single place harvesting of both, the algae as well as fishes can be done. This would increase the profitability for the owner if they already have aquaculture or hydroponics. While earlier they would get only a single product from the infrastructure, they could now get two products. Since harvesting time of algae is short, it would keep the owner busy and this could become a continuous source of income for them.
The major limitations of aquaponics are the high initial costs required for housing, tank, plumbing, pumps and bedding. One should also do thorough research for the chances of success of such project. The system also has number of points of failure and requires intensive maintenance.
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CROATIAN CENTER of RENEWABLE ENERGY SOURCES