Evaluation Of The Environmental Impact Of An Aquaponics System

The Food and Agriculture Organization of the United Nations accepted that soil-less agricultural practices are among economic, scientific, and technological developments in the agriculture sector over the last 200 years. These emerging farming techniques (i.e., hydroponics, aquaponics, and aeroponics) are environmentally friendly. They can be a good production system in a controlled indoor environment or open-air with few possible alterations.

Aquaponics is a combination of two agriculture technologies: recirculation aquaculture and hydroponics, within a close loop. It is less energy-intensive, environment friendly, and has less water consumption with a minimum requirement of chemicals or fertilizers. However, other factors govern their agricultural operations, such as climatic conditions, water quality, etc.

Above all, it’s important if aquaponics is really resource-efficient and economically viable for small and marginal farmers. To understand the same, and environmental impact assessment of a small solar-powered aquaponics system is carried out using a simple life cycle assessment (LCA) methodology. The assessment provided visualization of potential benefits for farmers, which can be achieved with the help of the proposed system. The study also has highlighted if solar-powered systems are useful for agricultural production or grid-based power is more useful.

Introduction

Global fish production is anticipated to rise to 204 million tonnes by 2030. Whereas aquaculture production is estimated to reach 109 million tonnes by 2030 with a cumulative increase of 32% over 2018 [1]. India is the third-largest country globally, with 10.8 million tons of fisheries production and out of which aquaculture production is 5.7 million tons [2].

However, with only 2.5% of the entire country’s arable land area, the state of Punjab’s inland fisheries contribute 194.98 million US dollars to the state value addition in the year 2019- 20 [3]. With this small arable land space, Punjab also contributes 31% rice and 35.5% wheat to the central pool in the total production of these commodities at the national level [4].

When comparing rice and fish production, the greenhouse gas emissions due per kg of rice and fish are 858.9 kg CO2 eq. and 756.5 kg CO2 eq. respectively [5], which is a significant difference in shear share. However, the difference in the price farmers get per kg of each product sold is significantly large. General observations derived based on discussion with farmers in Punjab and range and characteristics manufactured and/or assembled in this system.

In this context, the main challenge in modeling and analysis is now not only to cope with single products, a limited product range, or existing product families but also to be able to analyze and to compare products to define new product families. It can be observed that classical existing product families are regrouped in the function of clients or features.

However, assembly-orinted product families are hardly to find. On the product family level, products differ mainly in two main characteristics: (i) the number of components and (ii) the type of components (e.g. mechanical, electrical, electronical).

Classical methodologies considering mainly single products construction/development. The subsidy provides a minimum land area of 1 acre (80% culture pond and 20% nursery pond). The farmers are also provided with finger link size fish seeds to be stocked in their fish ponds and technical advice from time to time during the fish farming. Some of the Punjab state fisheries development board’s extension offices or training centers also provide support in fish feed preparation [6].

The varieties generally found suitable by the Punjab fisheries department are – Catla, silver carp, grass carp, rohu, mrigal carp, and common carp. They all are found suitable as per the climatic condition of Punjab to grow in fish farming. These conditions are beneficial for farmers with a minimum of one-acre land or more, so he is not entirely dependent on fish farming.

However, fish farming is assumed to be a cash crop, but sometimes due to small mistakes in fish in the pond, the farmer depended on fish farming to not earn sufficient money to sustain. Therefore, looking at the promising aspects of fish farming and the possibility to provide it as a technical and economical intervention for small and marginal farmers, the study has analyzed small-scale aquaponics for small and marginal farmers.

The system under analysis is a solar-based aquaponics system on deep water culture (DWC) system. Further, to assess the system’s environmental impacts, a simple life cycle assessment (LCA) methodology has been utilized. LCA is a proven tool for evaluating environmental burdens generated through different products or systems [7]. It has also been used frequently to assess fish or aquaculture production [8], [9].

The current study has utilized the Umberto LCA+ tool to evaluate the environmental impact of developing a small-scale aquaponics system powered by solar energy. The next section of the study provides a brief overview of contemporary literature on aquaponics systems and LCA studies of aquaculture and fish production.

Contemporary literature review

Aquaponics is a combination of two technologies – recirculation aquaculture (fish-farms) and hydroponics (soilless agriculture). Considering it as an emerging technological innovation system (TIS) and a viable concept of modern agriculture with a sustainable method of industrial and domestic food production.

However, different stakeholders have different opinions in terms of the future of aquaponics and hydroponics. A specific skill set is required to manage such complex systems for long-term use and how to design such a system with sustained outcomes [10].

However, the benefits associated with the small-scale aquaponics systems are useful for small and marginal farmers. In this context, Love et al. [11] described the operating conditions, inputs (water, energy, feed, etc.), and outputs (produced crop and fish) for a small-scale aquaponics setup in Maryland, USA.

The study observed a 1% loss of freshwater used for the system every day, with a total of 35950 liters of water replenished per year. Defa et al. [12] found that fish metabolism, residual feed, and temperature change affected the pH value of water and developed a predictive analysis. The system was monitored for ammonia, nitrates, phosphates, and other suspended solids to control the stocking density.

The study by Defa et al. also proposed a pH monitoring solution and sensors to record temperature and water flow using Arduino. Further, LCA is a valuable tool to assess the sustainability of the diversified aquaculture system in quantitative numbers. The assessment made through LCA serves as a basis for analyzing the system improvements [8].

An extensive literature of aquaculture LCA studies has been carried out by Bohnes et al. [9] to provide recommendations for system and policy development. The study reviewed 65 LCA studies of aquaculture production based on methodological characteristics (for example, functional unit, goal, and scope) and general characteristics (for example, type of culture, species, etc.).

A team from FAO also published a preliminary analysis of three aquaculture systems – Indian carps, Nile tilapia Bangladesh, and striped catfish in Viet Nam [13]. They found that Viet Nam catfish has the lowest emissions, followed by Nile tilapia in Bangladesh and Indian major carps. The current study compared a multi-culture fish production in the proposed aquaponics setup.

Yacout et al. [8] conducted an environmental impact assessment for two types of single culture – traditional fish farming in Egypt. The study assessed the production of Nile tilapia and intensive (smaller pond with comparatively more fish production) and semi-intensive (old earthen pond commonly of large size) production systems.

Another study by Forchino et al. [14] assessed the environmental impacts of two virtual aquaponics systems, and based on the observations; the research suggests that the raft system (RAFT) resulted in a less environmental impacting technique over the media-filled beds’ system (MFBS).

The study recommended that increasing the number of grow beds and using LCA for these alternative scenarios may represent a useful procedure to find new technical solutions to improve aquaponics’ sustainability and profitability.

The research favors a need for quantitative research to support the development of economically feasible aquaponics systems. The analysis showed that aquaponics has a vast potential and can be an essential driver for developing integrated food production systems. Aquaponics could be a useful technology for arid regions facing water stress problems [15].

Conclusions

The study has analyzed the environmental impacts of an aquaponics system developed in Punjab, India, based on the solar power supply. The setup’s key motivation was to identify technological and economic interventions for the small and marginal farmers in the state. The rate of water table depletion is high in the state, making it imperative for farmers with small landholdings to adopt alternative farming methods.

Aquaponics and hydroponics are some promising methodologies in the same context. The study found that the plastic-based equipment/products used in these new systems are majorly responsible for the environmental impact. However, the study also found that a solar-powered system for a setup like hydroponics/aquaponics can be very useful for farmers in the long term (>5 years).

The monitoring equipment used for the analysis purpose will be omitted when the system’s viability can be proved in a positive manner for the climatic conditions of the state of Punjab. The study is limited to assess an aquaponics system from an environmental perspective.

In contrast, the inclusion of economic aspects in the analysis could be a future research aspect to support the system’s economic viability. Which will also encourage small farmers and promoting agencies on return on investment of the system. Conducting a comparative analysis of the hydroponics system versus the aquaponics system in Punjab (an agricultural rich state) will open a new horizon for the research community and Punjab farmers.

Source: Bhakar, V., Kaur, K., & Singh, H. (2021). Analyzing the Environmental Burden of an Aquaponics System using LCA. Procedia CIRP, 98, 223-228.

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