Today I’m going to give you a quick view of a great possibility towards sustainable agriculture and that is “Aquaponics”. So let’s get started!

The basic queries are:

What is Aquaponics? How does it work? What is the mechanism of biofilter? What are the equipment to set up an Aquaponics system?What kind of plants can be grown & fish can be reared here? Whar are the benefits & weaknesses,potential uses & applications Scope in Bangladesh?

WHAT IS AQUAPONICS?

The answer lies in the word itself as “Aqua” means water & “ponics” refers to work. So, it’s a method of growing plants in water & using this as a habitat for rearing fish too. It’s a mutually beneficial cycle where water is cleaned up continuously & the toxic nutrients for the fish are uptaken by plants.

HOW DOES IT WORK?

Well, the core of aquaponics is the nitrogen cycle. It all starts with ammonia which is a waste product from the respiratory cycle of the fish as well as decomposing fish food & fish waste. A high concentration of Ammonia is toxic to the fish. In every aquaponics system exists nitrifying bacteria named Nitrosomonas which converts ammonia to nitrite. Unfortunately, nitrate is even more toxic to the fish than ammonia. Luckily, there is another class of bacteria in this system which is called Nitrobacter. Nitrite is converted to nitrate by this beneficial bacteria. Nitrates are a great nutrient source for plants. Thus, the nitrogen cycle converts toxic waste products into less toxic nutrients that plants can use. The nitrogen cycle & beneficial bacteria play a vital role in aquaponics.

MEANING & MECHANISM OF BIOFILTER

Biofilter can be made of any inorganic substrates like gravel or hydroponic substrate which provides a place for beneficial bacteria to live & proliferate. Water from the fish tanks is pumped through these biofilters. Ammonia converts into usable nitrates. Then the water goes to the plant tanks where nitrates are used & clean water returns to the fish tanks

EQUIPMENT TO SET UP AN AQUAPONICS SYSTEM

1. Fish tanks 2. Media beds 3. Water pumps 4. Electricity source

PLANTS & FISHES THAT CAN BE USED IN AQUAPONICS

PLANTS : Lettuce, kale, cabbage, cauliflower, broccoli, radish, carrot, beet, spinach etc. Herbs like mint, basil, chives etc.

FISHES : Tilapia, carp, koi, catfish etc. Ornamental fishes like fancy goldfish, angelfish, guppies, swordfish etc.

BENEFITS & WEAKNESSES

BENEFITS

Fast plant growth: By providing nutrients & an oxygen-rich environment for the roots of aquaponics plants make them grow 3 times faster than that of the soil.

Health: As it is pollution and chemical-free the grown fish, vegetables & herbs are healthier than those of the conventional production methods.

Reduced Water Use: Compared to soil gardening, aquaponics uses 90% less water as it is continuously being recycled.

Smart Farming: As it’s a soilless system, there’s no soil ploughing, turning or even weeding. So, aquaponics reduces this kind of labour & cost.

Food Security: Having a replenishing food source at home fresh & healthy produce is available all around the year.

WEAKNESSES

High initial start-up costs compared with both hydroponics & soil production systems. Requires deep expertise in the natural world & technical skills. It has energy demand so it adds up energy cost. Needs effective filtering of organic solid.

POTENTIAL USES & APPLICATION

Domestic or small scale aquaponics: Small devices on kitchen benches with goldfish & herbs.Semi-commercial or commercial aquaponics: Larger systems growing silver perch fish & lettuce. Education: Creating a small system to bridge the gap between the general public & sustainable agricultural technique.

SCOPE IN BANGLADESH

As aquaponics systems can be of any size & can work anywhere indoor or outdoor, kitchen or industry, this system can be used as pilot in developing countries like ours to meet the food security needs of local people. Many people in Bangladesh are engaging in aquaponics practices, successfully producing both veggies & fishes. Let’s hope one day Aquaponics will be popular among general farmers of our country.

Mubashshira Mahmud Meem

Student,Sher-e-Bangla Agricultural University(SAU)