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Many studies provide ways to monitor and manage the aquaponics system, a closed-loop ecosystem that combines hydroponics—growing plants without soil—and aquaculture—raising fish—using cloud computing, the Internet of Things (IoT), and smart sensing technologies. A system operating at peak efficiency yields organic, healthful food with little water and no chemical fertilizer usage, therefore contributing to food security and sustainability. In order to develop our proposed aquaponic system based on Internet of Things technologies, this paper will centralize our endeavor to integrate big data tools, namely Apache Spark and Kafka, into the previous architecture for data collection and processing, as well as for the prediction of any anomalies in the system. [ABSTRACT FROM AUTHOR]

The demand for food is persistently increasing; the world is facing cannot be addressed with the land's additional natural resources and exploitation. Currently, the agricultural industry is the world's largest water user and consumes about 70% of the water in different processes. In this food and environmental crisis, the new methods for growing plants in the agricultural domain are various; one of these methods is aquaponics which is a sustainable agriculture system that combines two names: Aquaculture, which is the farming of fish and Hydroponic which is the cultivation of plants (Off-soil) using water enriched with mineral materials. Aquaponics comes as a solution to enhance farming and agriculture productivity. The attention towards the aquaponics system is increasing due to its high efficiency, availability, and fewer resources consumption. However, there is intensive automation, monitoring, and control requirement for a smart aquaponics system. To enhance the productivity of aquaponics, it is required to utilize IoT-based technologies and artificial intelligence (AI) algorithms. The main aim of this paper at hand consists of proposing a new contribution based on the Internet of Things (IoT) solution that could control and monitor water quality and environmental parameters by using the maximum of sensors(water level, water temperature, electrical conductivity, CO2, Taux Ammonia Nitrogen(TAN), etc.), and actuators (water pump, etc.,) in aquaponics farming. This paper provides an innovative solution based on an interoperable, secure, scalable, low-cost, fully self-powered, flexible, reliable and generic IoT architecture that meets the requirements of aquaponics. [ABSTRACT FROM AUTHOR]

Global environmental, social, and economic challenges call for innovative solutions to food production. Current food production systems require advances beyond traditional paradigms, acknowledging the complexity arising from sustainability and a present lack of awareness about technologies that may help limit, for example, loss of nutrients from soil. Aquaponics, a closed-loop system that combines aquaculture with hydroponics, is a step towards the more efficient management of scarce water, land, and nutrient resources. However, its large-scale use is currently limited by several significant challenges of maintaining desirable water chemistry and pH, managing infections in fish and plants, and increasing productivity efficiently, economically, and sustainably. This paper investigates the opportunities presented by plasma technologies in meeting these challenges, potentially opening new pathways for sustainability in food production. Population growth increases the pressure on agricultural systems, depleting resources and causing pollution. Aquaponics systems combine aquaculture with hydroponics in a single closed-loop system, where plant waste sustains the growth of fish food (e.g., larvae and worms), and fish waste provides nutrients to plants, thus reducing their physical, environmental, and economic footprint. Scale-up of aquaponics systems is hindered by the need to maintain a fine balance between conditions that sustain optimal productivity in intensive fish, plant, and nitrifying bacteria populations while mitigating pathogenic infections. The use of plasmas in aquaponic systems may help to resolve several key challenges such as disease and water-quality management, including removal of pathogens and pollutants, enhancement of plant growth, and extension of the freshness and safety of perishable plant and fish products. [ABSTRACT FROM AUTHOR]

Aquaponics, producing fish and vegetables in a closed-loop water system, reduces fertilizer use and water discharge, and is therefore promoted as a sustainable venture. A recent global study found that the majority of 257 surveyed aquaponics farms made losses, but the reasons have been poorly analyzed. Based upon grey literature and a post-hoc cost-benefit analysis for an investment in an aquaponics farm in the Philippines, this paper aims to assess the factors contributing to an appropriate level of returns. In the Philippines, vegetables are relatively well-priced, but if catfish were produced, a venture producing 1250 kg fish, 6000 kg lettuce, and 300 kg tomato per year would have a Net-Benefit-Cost Ratio of below 1.3 after 20 years. This ratio should be higher when one considers the risks against which a farmer cannot and should not insure its production, as argued in the paper. Depending on the species of both fish and vegetables, the quantity of nutrients coming from the former component imposes a fish volume: vegetable area ratio ranging from 1:30 to 1:100, thus the quantity of marketable fresh vegetables determines the size of an aquaponics enterprise. As a consequence, the investments in the fish component are relatively high and weigh heavily on the financial balance. For producers to successfully adopt aquaponics, they need to consider starting first with catfish, and then, as they get to master the system’s management, they can shift to a high-value fish species for niche markets. [ABSTRACT FROM AUTHOR]

An increase in fish consumption, combined with a decrease in wild fish harvest, is driving the aquaculture industry at rapid pace. Today, farmed seafood accounts for about half of all global seafood demand for human consumption. As the aquaculture industry continues to grow, so does the market for aquafeed. Currently, some of the feed ingredients are coming from low-value forage fishes (fish meal) and terrestrial plants. The production of fish meal can't be increased as it would affect the sustainability and ecosystem of the ocean. Similarly, increasing the production of terrestrial plant-based feed leads to deforestation and increased freshwater use. Hence, alternative and environmentally sustainable sources of feed ingredients need to be developed. Microalgae biomasses represent potential feed source ingredients as the cell metabolites of these microorganisms contain a blend of essential amino acids, healthy triglycerides as fat, vitamins, and pigments. In addition to serving as bulk ingredient in aquafeed, their unique array of bioactive compounds can increase the survivability of farmed species, improve coloration and quality of fillet. Microalgae has the highest areal biomass productivities among photosynthetic organisms, including fodder crops, and thus has a high commercial potential. Also, microalgal production has a low water and arable-land footprint, making microalgal-based feed environmentally sustainable. This review paper will explore the potential of producing microalgae biomass as an ingredient of aquaculture feed. [Display omitted] • Microalgae have a wide range of dietary profiles. • Microalgae based feed helps fish develop faster and produce better fillets. • Poly unsaturated fatty acids derived from microalgae can be used instead of fish oil. • Microalgae may be fed to fish as a pellet, paste, or polyculture. • After optimization, microalgae feed can be economically and environmentally sustainable. [ABSTRACT FROM AUTHOR]

Aquaponics is a promising sustainable farming method that combines aquaculture and hydroponics. It allows the growth of crops without soil, pesticides, or fertilizers, and with a minimum amount of water. In aquaponic systems, the design of the growing area is directly linked to the type of crop about to be planted. The type of crop directly determines, for example, the spacing between plants and between channels, which is critical to determine the footprint required and estimate the system productivity. This paper proposes a knowledge modeling approach to support the design of aquaponic systems by automatically determining the required characteristics of the aquaponic system based on crop selection. The knowledge modeling is outlined as an ontology model that formally describes the existent links between the aquaponic grow bed characteristics and its design parameters. This study gives practitioners the capacity to visualize the impact of the desired crop selection on the aquaponic system design, as well as supporting clearer decision-making regarding production facility layout and system design in aquaponic farms. [ABSTRACT FROM AUTHOR]

Due to the abrupt rise in population, the demand for food and energy has increased tremendously. The current challenge is to meet all these demands in future. To tackle the problems of energy crisis and food adulteration, the only solution is to become self-reliant in all means. The spectacular technological innovations in the areas of information and communication have aided to design this lifestyle. This paper delivers the concept of building self sufficient smart homes by coupling the areas of i-energy, aquaponics and vertical farming. Also, provides a scope for developing self-sufficient homes in Kerala. This paper elucidates the architectural design perspective of a house, which is bound to satisfy all the basic needs and encourages each individual to turn to a prosumer. [ABSTRACT FROM AUTHOR]

Abstract Aquaculture has experienced a burgeoning growth worldwide in the last decade resulting in nearly 50% of seafood originating from aquaculture farms. However, there are less studies on the utilization of the manure produced by aquatic organisms in comparison to warm-blooded livestock. Aquaponics offers more efficient utilization of nutrients and can reduce the operational costs in aquaculture. This paper presents the results of a study to identify the optimal settings to digest fish manure through a microbial-assisted aerobic bioprocess, using endogenous heterotrophic and nitrifying bacteria. The effects of pH (5.5, 6.0 and 6.5), temperature (30, 35 and 40 °C) and duration (1–30 days) on kinetics of nitrogen mineralization were investigated and compared to a control bioreactor (carried out without pH adjustment). The mineralization dynamics for all pH-controlled bioreactors revealed that only ammonification occurred. No nitrification was observed for all three-temperature conditions and throughout the entire bioprocessing period. The mineralization process in the control bioreactor, on the other hand, followed the typical non-inhibited nitrogen mineralization (i.e., release of ammonium followed by oxidation into nitrate). However, nitrate was only observed at temperatures <40 °C indicating a complete suppression of nitrification at higher temperatures. Analytical data and modeled parameters indicated that the bioprocessing of aquaculture solid waste for 15 days at 35 °C using either pH 6.0 or 6.5 maximized nitrogen bioconversion in the form of ammonium ions (NH 4 +). This study indicates the importance of temperature and pH optimization for more efficient processing of aquaculture solid waste such as fish manure. Graphical abstract Unlabelled Image Highlights • Aquaculture solid waste is rich in nitrogen and minerals. • Aerobic digestion converts aquaculture solid waste into liquid fertilizer. • pH, temperature and process duration impact the aerobic digestion of fish manure. • Aerobic digestion for 15 days at 35 °C and pH 6.0–6.5 maximizes N mineralization. [ABSTRACT FROM AUTHOR]

Abstract Aquaponics is largely recognized as a solution for sustainable food production as it follows a biomimetic natural system and the circular economy principles, allowing large food productivity on nonagricultural land, and at the same time strongly reducing inputs and waste. In this study, we collected technical, economic and production data from a pilot aquaponic plant producing lettuce (Lactuca sativa) and Nile tilapia (Oreochromis niloticus) realized in an urban context in Sicily (Southern Italy), very suitable area for aquaponic production in relation to the Mediterranean climate. Through the determination of Net return and Break Even Point, analysing on one side the items which contribute to the investment (planning, construction and set up) and to the running costs, and on the other side the revenues from sales of lettuce and tilapia, its financial feasibility has been assessed. The results of the financial analysis performed for the first year of the experimental activity of the pilot unit have clearly demonstrated that aquaponic farming is likely to be profitable since the operating income is positive and about €290. The sensitivity analysis outlined in this paper suggests that the economic viability of the pilot unit might be slightly more susceptible to a decrease in total revenue rather than in operating costs. Findings provide important insights to help future aquaponic entrepreneurs formulate a business plan and allow a wider development of such a productive technology as a valid technique in boosting urban farming in the Mediterranean climate. [ABSTRACT FROM AUTHOR]

Vibrio vulnificus , Vibrio parahaemolyticus and Vibrio harveyi are the causative agents of the most severe diseases of marine and brackish aquaculture systems. These are also associated with serious ailments in humans. The present paper unravels the virulence features/genes and antimicrobial resistance (AMR) phenotypes/genes of these Vibrio spp. isolated from natural disease outbreaks of marine/estuarine fishes of India for the first time. Results on virulence features showed that V. vulnificus infected fish can pose public health risk. While, it has been found clinically that V. parahaemolyticus without tdh and trh genes are pathogenic to fish, even though they are reported to be, not associated with human diseases. It was significant to note that virulence features of V. harveyi were induced at increased salinity. Analysis based on the percentage prevalence of susceptible isolates and variation coefficient of zone diameters categorized 17 antibiotics in terms of their efficiency against each fish pathogenic species. Multiple antibiotic resistance index (MARi) of the isolates ranged between 0.058 and 0.47. Results on MARi and percentage of multidrug resistance strains indicated that >50% of the isolates were from low antibiotic usage area. The study generated tetH sequence from V. parahaemolyticus for the first time, and the sequence revealed high identity to that of clinical strains. Presence of tetB/ tetH gene was identified as the predictor for the resistance against the first generation tetracycline, the most commonly used antibiotic against Vibrio spp. in aquaculture practices. The data on associations between AMR features predicted certain cross-resistance between antimicrobials within Vibrio spp. Altogether, the paper serves as the baseline for epizootic tracking of public health significant vibrios from diseased fishes, to devise practical guidelines for antibiotic use and to formulate efficient control measures against three Vibrio spp. in aquaculture, targeting final applications in the implementation of national green and healthy aquaculture practices. • Helps to devise control measures against three pathogens of aquaculture practices. • Data for epizootic tracking of public health important vibrios from diseased fishes. • First report on antibiotic categorization based on activity against fish pathogens. • Shows predictor genes for 1st generation tetracycline resistance in fish pathogens. [ABSTRACT FROM AUTHOR]

Aquaponics systems combine vegetable cultivation with fish culture (Rao et al., 2017). Several environmental factors influence water quality, among which dissolved oxygen is the most critical. The dissolved oxygen-related processes are nonlinear and unstable and are characterized by considerable time delays and time variances. In an aquaponics system, the dissolved oxygen content is affected by changes in the aquaculture water and in the greenhouse climate. Understanding the changes in dissolved oxygen and ensuring its stability requires effective prediction approaches and corrective measures. Traditional prediction methods are characterized by low stability, low accuracy and poor timeliness. A dissolved oxygen prediction model based on fuzzy neural networks is proposed in this paper. With a large number of inputs, the fuzzy network has high dimensonality, a complex model structure, and low precision, among other limitations. A genetic algorithm can be used to optimize the centre and width of the fuzzy neural network’s middle layer and determine the optimal parameter combination, thus improving the efficiency and predictive accuracy of the model (Liu et al., 2014). The results show that a fuzzy neural network optimized using a genetic algorithm is more stable, more accurate, and more suitable for predicting dissolved oxygen than a fuzzy neural network and backpropagation neural network in an aquaponics system. Predicting dissolved oxygen is critical to the stability of an aquaponics system. [ABSTRACT FROM AUTHOR]

Aquaponics is an approach of coupling two technologies: recirculation aquaculture (fish-farms) and hydroponics (soil-less cultivation of crops). While it is perceived as a way to contribute to more sustainable food systems, the technology is still in its infancy, with several challenges. This paper describes current conditions of development and identifies aspects that can promote or hinder future pathways. We focus our analysis on the EU, using Germany as an institutional case study, while also considering worldwide developments. We propose a framework to analyze aquaponics as an emerging technological innovation system at the interface between existing fish and plant production systems. The approach is explorative based on a literature review and interviews with experts. The main findings are that stakeholders have different views regarding the future development pathways, knowledge to manage complex systems in the long term is needed and it is still unclear how to design institutional conditions to deliver sustainable outcomes. [ABSTRACT FROM AUTHOR]

Aquaponics is not only a forward-looking technology but it has also been proposed as a tool for teaching natural sciences at all school levels, from primary school to university. Life cycle assessment (LCA) has become a widely accepted method of evaluating the environmental impact of products and services. In this context, the aims of this paper were:1) to create a low-price AP system for possible use as didactic tool using recovered material; 2) to evaluate the environmental impact of a micro AP model (1.5 m 2 ) through LCA analysis; 3) to verify whether this micro AP model is representative of full-scale AP systems (>50 m 2 ) in terms of water quality and water consumption. Both, the water quality and the average daily water consumption of our system were in line with data reported in literature for larger aquaponics. LCA shows that materials and energy flows linked to the system management practices and energy consumption principally contribute to environmental impacts. The cumulative annual energy demand of micro aquaponic system was 1040.5 kWh; assuming that this system was built for a class of 25 students, the energy consumption of the learning activity using the proposed micro aquaponic system would be 41.6 kWh student −1 year −1 . The results showed that the micro aquaponic system reliably mimics a full-scale unit and that it is a teaching tool with a relatively low environmental impact. [ABSTRACT FROM AUTHOR]

Food security and sustainability is a major concern for Singapore due to its rapid urbanization, land scarcity, and low local food productions of fish and leafy vegetables. This paper attempts to design and develop a smart aquaponics system that can synergize fish farming and plant growing. Various sensors, actuators, microcontroller, and microprocessor were employed in the system to monitor and control water quality, light intensity, and fish feed. To ensure healthy growing environment for fish and plant, early warnings in form of email, short message service, and push notification are automatically sent to the user when the sensor detects any abnormal condition. Concurrently, the respective actuator will intervene and rectify the abnormal condition without human interference. Moreover, fish feed is dispensed at the user preset timings of the day. All system activities and live sensor measurements are securely stored in a cloud storage for data analysis. User-friendly web and mobile applications were also created to provide graphical user interfaces between the aquaponics system and the user. Additionally, the user can monitor the aquaponics facilities live from web application through a camera module of the system. As such, the proposed smart aquaponics system has demonstrated to be a self-sustainable, cost-effective, and eco-friendly urban farming that can attract commercial farmers and home gardeners. [ABSTRACT FROM AUTHOR]

• An overview of generative adversarial network (GAN) architectures is presented. • The application of GANs in agriculture is reviewed. • The challenges and opportunities of GANs are discussed. In agricultural image analysis, optimal model performance is keenly pursued for better fulfilling visual recognition tasks (e.g., image classification, segmentation, object detection and localization), in the presence of challenges with biological variability and unstructured environments. Large-scale, balanced and ground-truthed image datasets are tremendously beneficial but most often difficult to obtain to fuel the development of highly performant models. As artificial intelligence through deep learning is impacting analysis and modeling of agricultural images, image augmentation plays a crucial role in boosting model performance while reducing manual efforts for image collection and labelling, by algorithmically creating and expanding datasets. Beyond traditional data augmentation techniques, generative adversarial network (GAN) invented in 2014 in the computer vision community, provides a suite of novel approaches that can learn good data representations and generate highly realistic samples. Since 2017, there has been a growth of research into GANs for image augmentation or synthesis in agriculture for improved model performance. This paper presents an overview of the evolution of GAN architectures followed by a first systematic review of various applications in agriculture and food systems (https://github.com/Derekabc/GANs-Agriculture), involving a diversity of visual recognition tasks for plant health conditions, weeds, fruits (preharvest), aquaculture, animal farming, plant phenotyping as well as postharvest detection of fruit defects. Challenges and opportunities of GANs are discussed for future research. [ABSTRACT FROM AUTHOR]

• Halophytes can desalinize the soil and increase the productivity of crops. • Some halophytes are used as intercropping and rotating species to reduce soil salinity. • Many halophytes are efficient when they are integrated in aquaponic systems. • Many Mediterranean halophytes have potential multipurpose uses. • Halophytes may find niches in the demanding Mediterranean market. The loss of agro-biodiversity, climate changes and food insecurity are major challenges in the Mediterranean countries with potentially multidimensional consequences. With respect to salinity, approximately 18 million ha, corresponding to 25 % of total irrigated land in the Mediterranean area, are salt affected. Intensive cropping and the excessive use of expensive inputs such as water and fertilizers aggravate this situation. Understanding how we could improve crop productivity in salinized environments is therefore critical to face these challenges. Our comprehension of fundamental physiological mechanisms in plant salt stress adaptation has greatly advanced over the last decades. However, many of these mechanisms have been linked to salt tolerance in simplified experimental systems whereas they have been rarely functionally proven in real agricultural contexts. The sustainability of farming systems in salt affected Mediterranean soils can be effectively achieved by the use of salt-tolerant halophyte plants even more effective through the use of intercropping, crop rotation and aquaponics.. Moreover, if these halophyte plants are removed from the soil to grow other species, pressure on generating salt-tolerant crop plants would be reduced and much healthier crop plants would be cultivated in less stressed saline soils. This paper will focus on the sustainable practices based on the cultivation of halophytes in saline soils by highlighting some experimental activities carried out at laboratory and field levels in the last few years. [ABSTRACT FROM AUTHOR]

Fresh vegetables available on Northern European markets usually originate from a high number of sources. Environmental impacts for these goods typically arise from the resources used in production and the long-distance transport in air-conditioned trucks. As such, environmental impacts are mainly attributed to direct energy consumption, water use and nutrient supply. The aim of this paper was therefore to investigate and evaluate possible solutions to reduce the environmental impacts of vegetables available on urban markets in Northern Europe. We hypothesise that for the production of lettuce and tomatoes in Northern Europe, a 4-step solution, i.e. 1) local production, 2) climate-controlled efficient greenhouses, 3) decoupled aquaponics, and 4) combined building architecture with waste heat and green waste reuse, will enable a low environmental impact. We defined the metropole Berlin as case example, and used simulation results from a proven greenhouse simulator as input to a comparing life cycle assessment of fresh lettuce and tomato. The assessment included a list of 12 midpoint environmental impact categories, e.g. global warming potential with 100 year horizon (GWP 100 ; kg CO 2 eq.), depletion of fossil fuel reserves (FRS; kg oil eq.), and water use (WCO; m3 water). Most impact categories decreased systematically when increasing the complexity of the local vegetable production. Compared to the mix of vegetables from different locations available on the market, the complete 4-step solution reduced WCO from water consumption to water saving: i.e. from 14.2 L or 3.3 L to −10.1 L or −0.21 L per package of 500 g tomatoes or 150 g lettuce, respectively. GWP 100 and FRS were below the values of the available market mix, e.g. GWP 100 decreased with 8.7% in tomatoes and 49.9% in lettuce. In conclusion, with the right set-up, local vegetable productions in urban regions can surpass the imported mix on environmental performance in Northern Europe. [Display omitted] • Full-scale greenhouse vegetable production and aquaponics simulator was combined with LCA. • Compared to hydroponics energy consumption was reduced by 19% or 30% in tomato or lettuce. • Compared to lettuce import-mix, local aquaponics can reduce global warming potential by 50%. • Lettuce and tomato produced in multi-loop aquaponics have negative water use. [ABSTRACT FROM AUTHOR]

Aquaponics is a farming method that promises to be a good alternative against the food and environmental problem the world is facing. It is a combination between aquaculture (farming of fish) and hydroponics (growing plants without soil), being a technique to grow plants with the aquaculture effluent. This technique claims to have high water use efficiency, does not use pesticides and reduce the use of fertilizers, which make this technology green and sustainable. Since the interest in aquaponics is increasing, the major challenge is to do it feasible and reliable at commercial scale. The concept of precision farming usually applied in the traditional farming sense is now being introduced, leading to the need to adopt sensing, smart and IoT systems for monitoring and control of its automated processes. Lately, valuable contributions have been made towards the introduction of fully and semi-automated systems in small-scale aquaponics systems by automation and manufacturing experts. This paper aims to support research towards a viable commercial aquaponics solution by identifying, listing, and providing an in-depth explanation of each of the parameters sensed in aquaponics, and the smart systems and IoT technologies in the reviewed literature. Further, the proposed review highlights potential gaps in the research literature and future contributions to be made in regards of automated aquaponics solutions. [ABSTRACT FROM AUTHOR]

Biophysical environments, socio-economic, and political shocks that hamper food production and affect access to food are a treat towards a country's capacity to achieve and maintain food security. Over the past couple of decades, food production at a commercial scale in non-traditional food production environments have been emerging. Among other agricultural systems, the opportunities aquaponics systems present are becoming more apparent. Nonetheless, aquaponics' ability to bring together hydroponics and aquaculture to produce nutritious food has prompted more attention in terms of its economic viability and sustainability. In this paper, we present the reasons why aquaponics might be part of the solution in arid countries with particular focus on the State of Qatar. • Aquaponics is gaining momentum and is being considered as a solution for food production in arid environments. • The cost-effectiveness of aquaponics is promising given that the country's energy resources. • Institutional support will be required to promote the commercial trials of aquaponics and proliferation in the country. [ABSTRACT FROM AUTHOR]

• CRF system are structurally and functionally conserved in mammals and fish species. • CRF system are widely distributed in the brain and gastrointestinal tract, which may relate to feeding regulation. • CRF system as anorexigenic factors to reduce the feeding, such as UI/SVG/UCN1, UCN2, UCN3, and CRF. • There may be some mechanisms in CRF system in animals feeding regulation. CRF system is comprised of 4 homologous lineages, 2 main receptors (CRF-R1 and CRF-R2), and a binding protein CRF-BP. The homologous lineages are corticotropin-releasing factor (CRF), urotensin I (UI)/sauvagine (SVG)/urocortin 1 (UCN1), urocortin 2 (UCN2), and urocortin 3 (UCN3), and UI, SVG, UCN1 are orthologous genes. CRF system genes are widely distributed in the brain and gastrointestinal tract, which may relate to feeding regulation. According the research progress about CRF system on mammals and non-mammals, this paper summarized the discovery, structure, tissue distribution, appetite regulation and mechanism of CRF system in animals, which can provide the reference for further research and production of feeding regulation and growth in mammals and fish species. [ABSTRACT FROM AUTHOR]

A sustainable aquaculture production involves alternatives, as recirculating aquaculture systems (RAS), in order to increase the water supply efficiency. This paper aims: a) to propose a method for dimensioning a RAS filled and additionally supplied with water from a rainwater harvesting systems (RHS) and; b) to evaluate the efficiency of the system based on the supply of rainwater from the RHS, the quality of water in the RAS, and the development of aquatic organisms. A pilot aquaculture farm for rainbow trout (Oncorhynchus mykiss) production was designed and dimensioned. On one hand, the RAS with a configuration based on a treatment tower provided acceptable values of pH, TAN, and alkalinity. The temperature was slightly above the recommended temperature but did not negatively impact trout development. On the other hand, the water use efficiency reached 178 L/kg of fish, instead of 210,000 L/kg in an open flow system for trout rearing. The RHS fulfilled the additional required water on the test period of the pilot farm and is expected to supply at least 92% on average during the useful life. Regarding the aquatic organisms' development, the system allowed both a better Length/ weight ratio and a lesser mortality rate compared to previous studies of RAS. In contrast to other studies in the literature, the mathematical models for dimensioning the system were calculated as a function of the final biomass expected in the tank instead of the quantity of supplied feed. Therefore, this method confirmed the applicability of this alternative criterion for designing biofilters and aquaculture systems. [ABSTRACT FROM AUTHOR]

• Phosphate solubilising bacteria were used on hydroxyapatite from tilapia scales. • Different strains were tested, the most effective being Acidovorax oryzae. • P solubilisation efficiency of almost 40% was achieved. • High efficiency could be due to hydroxyapatite nanostructure (grain size 80–150 nm). • This process shows potential for waste valorisation and sustainable agriculture. The increased use of fertilisers is a well-known problem; linked to this, there is an always higher demand for phosphorus (P). Because of this, it is crucial to use P from all possible sources and, if necessary, turn it into a soluble form, available for plants/crops. In this paper we report the use of aerobic phosphate solubilising bacteria (PSB) on the scales of the tilapia (Coptodon rendalli) fish, a waste from the food industry; this is the first time that PSB were employed on fish scales to mediate the available P. The scales were calcined to 700 °C to obtain a nanoscale powdery material (more easily solubilised), made of hydroxyapatite, Ca 10 (PO 4) 6 (OH) 2 , a calcium phosphate with very low solubility. Seventeen different PSB strains were tested for their ability to solubilise phosphate (commercial tricalcium phosphate - TCP) and hydroxyapatite from fish scale (FSHA). The best performing bacterial strain (Acidovorax oryzae ZS 1–7) led to a P solubilisation more than 60 times higher than the negative control – at 325 mg/L, almost 40% of the available P was solubilised – one of the highest increased efficiencies reported for PBS. Such solubilisation was linked to a decrease of the pH to more acidic values of about 4. The strain ZS 1–7 showed higher P solubilisation efficiency with fish-derived FSHA than with commercial TCP. This approach showed a promising strategy for the valorisation of residues of the fish industry, turning them into a source of P, to be used for sustainable agriculture. [ABSTRACT FROM AUTHOR]