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What is Aquaponics and How Does it Work?

Nutrient film technique lettuce

Intro

The ecological effects of traditional agriculture on the land, the water, and other essential resources constitute a issue, both ecological and environmental, as well as economic and political. This is one of the drivers pushing up interest in sustainable farming methods. Among these cutting-edge techniques, aquaponics stands out as an efficient solution capable of resolving the complex issues that conventional farming faces.

Aquaponics is a viable way to produce food without harming the environment by using substantially less water than traditional methods, reducing the need for synthetic fertilizers, and minimizing waste production. In this article, you will read a thorough explanation of the aquaponic system. Let’s read!

Aquaponics

Aquaponics is an environmentally friendly agricultural method that ingeniously combines the aspects of hydroponics and aquaculture. Hydroponics is a process that involves growing plants in nutrient-rich water without using soil. Whereas aquaculture is the breeding and raising of aquatic species like fish and shellfish.

Aquaponics joins the biological processes in both systems, and creates a harmonious closed-loop ecosystem where fish and plants may co-exist and thrive, while limiting the amount of chemicals and wastewater, drawbacks inherent in hydroponics and aquaculture.

History

Around 1000 AD, the Aztec Indians used floating rafts on Lake Texcoco for cultivating plants. The Aztec chinampas in Mexico are considered the precursors of modern aquaponics. Early aquaponics techniques were also observed in Eastern Asia, China, Thailand, and Indonesia.

In Asia, aquaponic farming methods involve cultivating rice in paddy fields with the help of fish, like catfish.  An early example of integrated agriculture can be seen in how the wastewater from the catfish tanks was used as a natural fertilizer for rice fields and other crops.

Modern Aquaponics

Ancient civilizations in Asia and Central America raised the idea of cultivating plants and fish together. The modern aquaponics we know today was first developed in the 1970s. Dr. Mark McMurtry attributes the advancement of contemporary aquaponics to the efforts of the New Alchemy Institute and North Carolina State University.

The New Alchemy Institute was committed to investigating and creating ecologically sustainable systems to meet human needs in renewable energy, aquaculture, agriculture, landscaping, and housing. They experimented with developing edible fish in above-ground tanks as part of their aquaculture research. These tanks’ nutrient-rich wastewater was reused to feed crops raised in a greenhouse.

Dr. McMurtry was motivated by the New Alchemy Institute’s works, and then he started the research on aquaponics.

Professor Doug Sanderson developed the first closed-loop aquaponics system in the middle of the 1980s. In their aquaponic system, the wastewater from the fish tank was used to irrigate crops like cucumbers and tomatoes in the grow bed that filled with sand. Water was purified through the sand, which worked as a natural bio-filter. The fish tanks received the filtered water back, establishing an eco-friendly and self-sustaining environment that created the model for modern aquaponics techniques.

How does it work?

Hydroponics and aquaponics are quite similar systems for growing plants, except for adding fish to the aquaponics water tank. The Aquaponics cycle has a prominent division of work: fish live in the tank, while plants thrive in the grow bed. Fish, plants, and bacteria are the main components of the aquaponics setup. 

The most important interaction starts with nutrient-rich water from the fish tank, which contains fish waste, carefully directed into the grow bed. A complex network of naturally existing beneficial bacteria takes centre stage in this dynamic environment. These beneficial bacteria transform ammonia first into nitrites and then into nitrates.

At this point, plants take these nitrates and a variety of other essential nutrients to grow. As responsible stewards, the plant’s roots clean and filter the water before the water is pumped back into the fish tank where the fish lives. The cycle starts again with new, clean, and oxygenated water.

The Nitrogen Cycle in Aquaponics

The nitrogen cycle is a crucial mechanism in aquaponics. Its primary function is to change poisonous ammonia into a much less harmful nitrate chemical. The cycle starts when fish excrete ammonia, which gradually builds up in the water. Beneficial bacteria are essential for the aquaponics nitrogen cycle to function. Beneficial bacteria, such as Nitrosomonas, play a vital role in the nitrogen cycle, which turns ammonia into nitrites.

These nitrates provide essential nutrients like phosphorus and Nitrogen to promote plant growth.  Nitrobacter, another group of helpful bacteria, refines the process by changing nitrites into nitrates. In turn, these nitrates become a priceless supply of nutrients that are necessary for the flourishing growth of plants.

In the aquaponic system, Bacteria form colonies on various surfaces, including the grow beds and the media used for plant cultivation. These surfaces provide a favourable environment for the growth of these microorganisms. Without these bacteria, the harmful ammonia will buildup and harm the fish. That’s why maintaining the aquaponic system and the nitrogen cycle is important.

Types of Aquaponics System

There are three main types of aquaponics systems; we will discuss each in more detail below.

Media-Based Aquaponic System

Media-based aquaponics are also known as Flood and Drain systems. It is the most common and best aquaponics system for beginners because it is easy to set up and manage. In this method, plants are grown in a unique grow bed or container filled with a particular growing media such as gravel, lava rock, or clay pebbles to support the roots of the plants.

A cyclical process occurs in this system: a bell siphon regularly moves water from the fish tank into the grow bed. The grow bed is periodically flooded, ensuring the plants have access to the vital nutrients in the water. The water then drains backward to the fish tank. The media used to support the plants acts as a mechanical and biofilter to capture and break down wastes.

Significantly, all waste products decompose inside the grow bed, including fish excrement and organic matter. In some cases, it is common to include earthworms in the growing media to help effectively break down waste products.

Pros

Cons

  • Best for small-scale businesses.
  • Efficient biofiltration.
  • A more comprehensive range of plants can grow.
  • Low maintenance.
  • Requires a small number of components.
  • Excessive water usage.
  • Needs more cleaning.
  • Media Costs make it more expensive to expand

Raft System

Raft system, also known as deep water culture aquaponics (DWC), it is the most advanced technique of aquaponics that pumps nutrient-rich water through wide channels, usually kept at around 20 centimetres. These canals are home to rafts that effortlessly float on the water’s surface. These rafts are made of foam boards or polystyrene.

The plants are cultivated on raft boards supported by net pots fitted into holes in the rafts. The roots of the plants gently dangle into the nutrient- and oxygen-rich water, where they actively absorb the essential nutrients with the help of an air pump and air stones.  The nutrient-rich water maintains a steady flow, starting from the fish tank and moving through a thorough filtration procedure. It then goes to the special raft tank, where the plants thrive.

After feeding the plants, the water completes its cycle by returning to the fish tank. Keeping the raft tank separate from the fish tank helps the aquaponics system run effectively. In addition, this aquaponic system can be used for larger root zone plants. It is best suited for warmer areas because it can withstand daily temperature variations.

Pros

Cons

  • Energy efficient as compared to other aquaponic systems.
  • Inexpensive
  • Suitable for urban areas
  • Provides high yields.
  • Risk of disease
  • High maintenance
  • Needs additional filtration.

Nutrient Film Technique (NFT)

NFT is the best aquaponics system due to low maintenance and space efficiency. Plants grow in long, narrow channels in NFT method. In these channels, a thin, continuous film of water softly cascades, providing the nutrient rich water and essential oxygen to the roots of the plants.

Like a raft system, the water travels from the fish tank via several filtering elements, through the NFT channels containing the plants, and back to the fish tank. However, a separate biofilter is necessary in the NFT system. This biofilter is essential in the system because the NFT channels provide little surface area for the helpful bacteria that required for waste conversion to thrive. Compared to other systems, the NFT system is suitable for aquaponics gardening systems as it is easy to access.

Pros

Cons

  • Uses minimal water.
  • Automatable system.
  • Reduces labour expenses.
  • Higher yield.
  • Not suitable for flowery or larger plants.
  • Higher possibility of temperature changes in water.
  • Clogs easily

How to Maintain an Aquaponic System?

An aquaponics system is a complex ecosystem, that depends on the interactions of fish, plants, and bacteria to function properly. Frequent maintenance is necessary to make this system more productive. The following crucial factors will help you maintain your aquaponics system.

  • Ensure enough dissolved oxygen for the plants and fish by maintaining the water circulation and aeration.
  • You can maintain good water quality by routinely evaluating the pH, water temperature, water source, and ammonia levels. The water serves as a conduit for nutrients to reach plants and fish.
  • Avoid overcrowding in the water with too many fish. Fish overcrowding can lead to stress and excessive ammonia production, both of which are harmful to the health of the fish.
  • Do not overcrowd your grow bed, floating raft, or NFT pipes with plants. Plants require space to receive enough nutrients and sunlight. Keep in mind the exact aquaponics fish-to-plant ratio.
  • Don’t feed your fish excessively. Feed your fish the right fish food based on how much they can eat in five minutes. After feeding, remove any leftover fish food because it might raise ammonia levels and block the system.

What Type of Plants can you Grow in Aquaponics?

Aquaponics is a method for growing almost any plant. However, plants also require varied light, room, and nutrients. Consider the plants listed below; these are the best plants for aquaponics to get higher results from your aquaponic system.

Media-based aquaponics system: Lettuce, tomatoes, ginger, eggplant, cucumber, and any other plants that will fit your grow bed can all be developed in a media-based aquaponics system.

Raft System: Tiny rooted plants, including watercress, mint, Swiss chard, bok choy, lettuce, basil, and kale.

Nutrient Film Techniques (NFT): lettuce, strawberries, spinach, parsley, dill, and other small-rooted plants are best for aquaponics nutrient film technique (NFT).

Which Fish Are Best for Aquaponics?

Choose the best fish for aquaponics and know how to properly care for the fish in your approach to get the most growth output.

The following fish are commonly cultivated in aquaponics systems:

Edible Fish Species:  tilapia, carp, catfish, trout, largemouth bass, salmon, bluegill, jade perch, and barramundi.

Ornamental Fish Species: Koi, Guppies, tetras, and goldfish.

Why is Aquaponics Important?

Aquaponics is important for several reasons. First, it represents an effective and sustainable way of food production that tackles the two significant issues of aquaculture and hydroponics. This closed-loop technology minimizes the environmental effect of conventional agriculture while conserving water and reducing the demand for synthetic fertilizers.

Aquaponics can be used in various environments, making it suitable for urban and rural settings. Moreover, it provides a resource-efficient, locally adaptable, and sustainable approach to agriculture, making it an essential part of future food production systems in the face of expanding global issues like population increase and climate change.

Conclusion

Aquaponics is a prime example of a nature-inspired invention that can increase food security while lowering the environmental impact of food production by establishing symbiotic interactions between fish and plants. However, it’s crucial to note that aquaponics requires a commitment to consistent upkeep to ensure its success. In a world where sustainable, effective, and regionally adapted agricultural approaches are increasingly important, this dedication to maintaining the system is critical for attaining its full potential. You can get an expected higher yield with more outstanding care and maintenance.

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