Aquaponic System Research Articles

Smart hydroponic monitoring using Internet of Things (IoT’s) supported by hybrid solar system

Aquaponics provides an alternative to farming on limited land by combining aquaculture and hydroponics in a symbiotic environment. Aquaponics practitioners usually only focus on techniques and the use of fertilizers. But over time, the need for science and technology has become an important factor in the application of more modern aquaponics based on the Internet of Things until the 4.0 revolution. Routine and intensive monitoring can certainly be an obstacle for aquaponics actors who have limited time and human resources. So we need an automation system that can be used for remote monitoring and control in real-time with a high level of mobility. The presence of solar energy leads to the use of hybrid power plants. A smart grid is a modern electric grid concept that has a high degree of flexibility, accessibility and efficiency. The pattern of gardening with hydroponics provides a solution for residents who live in urban areas because hydroponics is a way of planting with water media which is an alternative medium to replace soil. The use of IoT technology makes it easy because maintenance can be done by the system itself and monitoring and control of the hydroponic system can be done anywhere. A smartphone can be used as a device to monitor and control the system. Several studies related to this aquaponic monitoring and control system have also been carried out with various innovations, such as making an aquaponic system with IoT technology by integrating it on android applications and websites with several actuator controls. In this study, it was integrated between IoT-based aquaponic control systems and hybrid solar systems to accommodate power consumption. The system has been operating well and can control cultivated plants.

Black Soldier Fly (Hermetia illucens) Frass on Sweet-Potato (Ipomea batatas) Slip Production with Aquaponics

Nutrient supplementations are often added to aquaponic systems to optimize plant production, and black soldier fly larvae frass is a promising organic fertilizer. However, the mineral composition of the frass is substantially influenced by the initial substrate. In an 8-week study, sweetpotato slips were cultured at commercial stocking densities in an aquaponic system which received weekly additions of either BSFL frass made from high-nitrogen expired fish diets or low-nitrogen fruits/vegetables. The sweetpotato slips (≥8 nodes) were harvested weekly. Despite differences in the mineral composition between the frass types, the water quality as well as slip production/sugar content were unaffected by frass type. The results indicate that a wide array of substrates may be suitable for producing black soldier fly larvae frass as a fertilizer in aquaponic systems. Lastly, aquaponics is a viable system to commercially produce sweetpotato slips.

Nutrients Use Efficiency in Coupled and Decoupled Aquaponic Systems

Aquaponics is currently undergoing a transformation into an intensive food production system. The initially applied systems focused on small-scale, fish-centric coupled (CAP, the aquaculture, and the hydroponic units are arranged in a single loop, and the water flows continuously from the fish tanks to the plant unit and back) aquaponics. More recently, the primary area of research interest has shifted toward larger-scale, plant-centric decoupled (aquaculture and hydroponics units are arranged in a multi-loop setup as separate functional units that can be controlled independently) systems, aiming to achieve greater economic benefits and employ more environmentally friendly practices. The objective of this study was to address gaps in the expansion of decoupled larger-scale aquaponics and to provide a comprehensive understanding of the water and nutrient flow in the system. For this purpose, experiments were performed in a greenhouse on CAP and DCAP systems, while this study also included measurements in a pure hydroponic system (HP). This study presents an assessment of the water and nutrient flow in four different crops: basil; cucumber; parsley; and tomato, all co-cultivated with a tilapia aquaculture system. Significant nutrient deficiencies and imbalances were identified in the CAP solution, leading to pronounced impacts on nutrient assimilation, particularly for fruiting vegetables. However, the average nutrient use efficiency (NUE) for nitrogen, phosphorous, potassium, and calcium was found to be 42% higher in the CAP treatment compared to HP and DCAP treatments. The nutrient solution in the DCAP treatment did not exhibit differences in water quality parameters and nutrient efficiency when compared to HP, resulting in similar effects on nutrient assimilation. Nonetheless, it was observed that DCAP plants exhibited superior NUE compared to HP plants.

Detection of Fungal Diseases in Lettuce by VIR-NIR Spectroscopy in Aquaponics.

One of the main challenges facing the development of aquaponics is disease control, due on one hand to the fact that plants cannot be treated with chemicals because they can lead to mortality in cultured fish. The aim of this study was to apply the visible-near-infrared spectroscopy and vegetation index approach to test aquaponically cultivated lettuce (Lactuca sativa L.) infected with different fungal pathogens (Aspergillus niger, Fusarium oxysporum, and Alternaria alternata). The lettuces on the third leaf formation were placed in tanks (with dimensions 1 m/0.50 m/0.35 m) filled up with water from the aquaponics system every second day. In this study, we included reference fungal strains Aspergillus niger NBIMCC 3252, Fusarium oxysporum NBIMCC 125, and Alternaria alternata NBIMCC 109. Diffuse reflectance spectra of the leaves of lettuce were measured directly on the plants using a USB4000 spectrometer in the 450-1100 nm wavelength range. In near-infrared spectral range, the reflectance values of infected leaves are lower than those of the control, which indicates that some changes in cell structures occurred as a result of the fungal infection. All three investigated pathogens had a statistically significant effect on leaf water content and water band index. Vegetative indices such as Chlorophyll Absorption in Reflectance Index (CARI), Modified chlorophyll absorption in reflectance index (MCARI), Plant Senescence Reflectance Index (PSRI), Red Edge Index (REI2), Red Edge Index (REI3), and Water band index (WBI) were found to be effective in distinguishing infected plants from healthy ones, with WBI demonstrating the greatest reliability.

Supplementation of potassium in aquaculture wastewater and its effect on growth performance of basil (Ocimum basilicum L) and pangasius (Pangasianodon hypophthalmus) in NFT-based aquaponics

An experiment was conducted for 120 days to optimize the potassium dose and investigate its effects on the growth performance of basil and pangasius in a nutrient film technique-based aquaponics. Potassium was supplemented as four different dosages assigned as T1 (90 mg/L), T2 (120 mg/L), T3 (150 mg/L), and T4 (180 mg/L) were compared to an unsupplemented control (C). Basil and pangasius were stocked at 24 plants/m² and 3.00 kg/m³, respectively. The highest basil yield occurred during the 3rd harvest in T4 (390.50 ± 4.25 g), followed by T3, T2, T1, and control. No significant difference in plant yield was observed between T4 and T3. Similarly, highest plant height, leaf length, leaf width, SFW, SDW, RFW, and RDW was recorded in T4 and T3 compared to control and other treatments. Potassium supplementation resulted in increased uptake of macro-micro nutrients viz., phosphorous, nitrogen, sulfur, potassium, copper, iron, zinc, and manganese in basil. The physico-chemical parameters and nutrient profile of culture water were found to be within the permissible limits for aquaponics. The body weight of fish didn't show any significant difference in control, T1, T2 and T3 while significantly lower body weight was recorded in T4. Significantly higher serum cortisol and glucose levels were found in T4. Considering the basil yield, nutrient and chlorophyll content of basil plant, water quality, body weight of fish, and fish stress parameters, supplementation of 150 mg/L (T3) of potassium was found to be the optimum dose for basil and pangasius culture in NFT-based aquaponic system.

Crop diagnostic system: A robust disease detection and management system for leafy green crops grown in an aquaponics facility

Crops grown on aquaponics farms are susceptible to various diseases or biotic stresses during their growth cycle, just like traditional agriculture. The early detection of diseases is crucial to witnessing the efficiency and progress of the aquaponics system. Aquaponics combines recirculating aquaculture and soilless hydroponics methods and promises to ensure food security, reduce water scarcity, and eliminate carbon footprint. For the large-scale implementation of this farming technique, a unified system is needed that can detect crop diseases and support researchers and farmers in identifying potential causes and treatments at early stages. This study proposes an automatic crop diagnostic system for detecting biotic stresses and managing diseases in four leafy green crops, lettuce, basil, spinach, and parsley, grown in an aquaponics facility. First, a dataset comprising 2640 images is constructed. Then, a disease detection system is developed that works in three phases. The first phase is a crop classification system that identifies the type of crop. The second phase is a disease identification system that determines the crop's health status. The final phase is a disease detection system that localizes and detects the diseased and healthy spots in leaves and categorizes the disease. The proposed approach has shown promising results with accuracy in each of the three phases, reaching 95.83%, 94.13%, and 82.13%, respectively. The final disease detection system is then integrated with an ontology model through a cloud-based application. This ontology model contains domain knowledge related to crop pathology, particularly causes and treatments of different diseases of the studied leafy green crops, which can be automatically extracted upon disease detection allowing agricultural practitioners to take precautionary measures. The proposed application finds its significance as a decision support system that can automate aquaponics facility health monitoring and assist agricultural practitioners in decision-making processes regarding crop and disease management.

Integrated hydroponics systems with anaerobic supernatant and aquaculture effluent in desert regions: Nutrient recovery and benefit analysis

Hydroponics is a resource-efficient system that increases food production and enhances the overall sustainability of agricultural systems, particularly in arid zones with prevalent water scarcity and limited areas of arable land. This study investigated zero-waste hydroponics systems fed by agricultural waste streams as nutrient sources under desert conditions. Three pilot-scale systems were tested and compared. The first hydroponics system (“HPAP”) received its nutrient source internally from an aquaponic system, including supernatant from the anaerobic digestion of fish sludge. The second system (“HPAD”) was sourced by the supernatant of plant waste anaerobic digestion, and the third served as a control that was fed by commercial Hoagland solution (“HPHS”). Fresh weight production was similar in all treatments, ranging from 488 to 539 g per shoot, corresponding to 5.7 to 6.0 kg total wet weight per m2. The recovery of N and P from wastes and their subsequent uptake by plants was highly efficient, with rates of 77 % for N and 65 % for P. Plants that were fed using supernatants demonstrated slightly higher plant quality compared with those grown in Hoagland solution. Over the duration of the full study (3 months), water was only used to compensate for evapotranspiration, corresponding to ~10 L per kg of lettuce. The potential health risk for heavy metals was negligible, as assessed using the health-risk index (HRI < 1) and targeted hazardous quotient (THQ < 1). The results of this study demonstrate that careful management can significantly reduce pollution, increase the recovery of nutrients and water, and improve hydroponics production.

Produção de alface hidropônica e aquapônica sob diferentes declividades e soluções nutritivas no sistema NFT

ABSTRACT The slope of cultivation channels and types of nutrient solutions in hydroponics and aquaponics influence nutrient absorption and plant production. This research aimed to evaluate lettuce production under different channel slopes and nutrient solutions in hydroponic and aquaponic systems using the nutrient film technique (NFT). A randomized block design was used, with three replicates, in a 3 × 5 split-plot scheme, with three nutrient solutions (conventional hydroponic solution and two wastewaters from the tilapia fish diets, with 15 and 18% of crude protein) and five slopes (2, 4, 6, 8 and 10%) of cultivation channels (PVC tubes). The following variables were evaluated: fresh and dry mass of shoot and roots and the chemical elements of the solutions. In the tilapia feed, the nutrient solution with 18% of protein (wastewater) provides greater production and accumulation of nutrients (N and P) in the lettuce shoot. The slope of 8% on cultivation channels provides greater production of iceberg lettuce, cultivar Lucy Brown. The different slopes and nutrient solutions studied did not influence the potassium (K) accumulation in the lettuce shoot.

Smart Home Aquaponic System Monitoring and Control with Internet of Things Using Mobile Application

Food security has been a recurrent concern for numerous nations, including Malaysia. Climate change and population growth exacerbate this issue by increasing necessity food. In past few years, aquaponics has proven beneficial for fish and plant production, based on the idea that if every household can generate its own fish and plants, the nation's overall food consumption will reduce. The suggested smart house aquaponics system comprises an assortment of internet-connected sensors, actuators, and ESP32 microcontrollers that continuously monitor, adjust, and record the water and air quality of the fish tank. The Internet of Things (IoT) mobile application feature can alert the user in the event of an abnormal system state in terms of maintaining the health and growth of fish and plants. The Internet of Things (IoT) mobile application feature can alert the user in the event of an abnormal system state in terms of maintaining the health and growth of fish and plants. When the pH and turbidity thresholds are surpassed, the pumps are actuated to either fill or drain the tank. The results show that the design for a smart aquaponics system that can be used in a home is able to monitor and control all the parameters that are needed to cultivate wholesome fish and vegetation.

Estimating the production of withaferin A and withanolide A in Withania somnifera (L.) dunal using aquaponics for sustainable development in hill agriculture.

Humanity is suffering from huge and severe difficulties, including changes in climate, soil degradation, scarcity of water and the security of food and medicines, among others. The aquaponics system acts as a closed loop consisting of aquaculture elements and hydroponics, which may contribute to addressing these problems. The aquaponics method is quickly expanding as the requirement to increase the production of sustainable herbal products, including medicinal compounds and foods, in freshwater systems and replenish phosphorous reserves shrinks. The current work is designed to increase the production of the antioxidants withaferin A and withanolide A in two varieties (Jawahar-20 and Poshita) of W. somnifera using the aquaponics technique. Total 100 seedlings (one month old) grown in soil initially were taken to be grown in aquaponics for a time period of 6 months.And 100 seedlings were placed in pots containing soil as control for study after six months. It was observed that the higher content of withaferin A was analyzed in the root and stem samples of Jawahar-20 and Poshita from the six-month-old plant of W. somnifera. The maximum content of withanolide A was examined in the root samples of the six month-old plants of Poshita (1.879 mg/g) and Jawahar-20 (1.221 mg/g). While the 6 month old Poshita seedling grown in soil recorded less withaferin A (0.115 ± 0.009b) and withanolide A (0.138 ± 0.008d). It is concluded that Poshita was found to be more promising for the enhanced production of withaferin A and withanolide A in the aquaponics system. Moreover, the root was observed as the best source for the production of withaferin A and withanolide A and the best age of the plant is 2 years for the production compounds in medicinal plants with futuristic perspective to hill agriculture integrated farming. compounds. Thus aquaponics can be an effective approach with enhanced yield of bioactive compounds in medicinal plants with futuristic perspective to hill agriculture and integrated farming.

Performance of fish sludge solubilization and phototrophic bioconversion by purple phototrophic bacteria for nutrient recovery in aquaponic system

Nutrient recovery from fish sludge in aquaponics is crucial to improve the economic output of a system sustainably and hygienically. Currently, fish sludge is treated using conventional anaerobic and aerobic mineralization, which does not allow the recovery of valuable nutrients in fish wastes. In this study, a two-stage approach (named as solubilization process and phototrophic bioconversion) is proposed to convert fish sludge into mineral nutrients and biomass nutrients using purple phototrophic bacteria (PPB), thereby promoting the growth of plants and fish simultaneously in aquaponics. Anaerobic and aerobic solubilization methods are tested to pretreat the fish sludge, generating substrates for PPB. Anaerobic solubilization yields 2.1 times more soluble chemical oxygen demand (SCOD) and 3.7 times more total volatile fatty acid (t-VFA) from fish sludge compared with aerobic solubilization. The anaerobic solubilization effluent indicates a CODt-VFA/SCOD of 60% and a VFA comprising 13.3% acetate and 49.0% propionate for PPB. The phototrophic bioconversion using anaerobic solubilization effluent under the light-anaerobic condition results in the highest biomass yield (0.94 g CODbiomass/g CODremoved) and the highest PPB dominance (Ectothiorhodospira, 58.7%). The anaerobic solubilization and light-anaerobic phototrophic bioconversion achieves 54.1% of carbon recovery efficiency (CRE) (in terms of COD), as well as 44.8% and 91.3% of nutrient recovery efficiency (NRE) for N and P. A novel multiloop aquaponic system combined with PPB-based nutrient recovery is proposed for the reuse of mineral nutrients and PPB biomass generated from fish sludge.

Integration of probiotics in aquaponic systems: an emerging alternative approach

Integration of probiotics in aquaponic systems: an emerging alternative approach

Estimation of morphological traits of foliage and effective plant spacing in NFT-based aquaponics system

Deep learning and computer vision techniques have gained significant attention in the agriculture sector due to their non-destructive and contactless features. These techniques are also being integrated into modern farming systems, such as aquaponics, to address the challenges hindering its commercialization and large-scale implementation. Aquaponics is a farming technology that combines a recirculating aquaculture system and soilless hydroponics agriculture, that promises to address food security issues. To complement the current research efforts, a methodology is proposed to automatically measure the morphological traits of crops such as width, length and area and estimate the effective plant spacing between grow channels. Plant spacing is one of the key design parameters that are dependent on crop type and its morphological traits and hence needs to be monitored to ensure high crop yield and quality which can be impacted due to foliage occlusion or overlapping as the crop grows. The proposed approach uses Mask-RCNN to estimate the size of the crops and a mathematical model to determine plant spacing for a self-adaptive aquaponics farm. For common little gem romaine lettuce, the growth is estimated within 2 cm of error for both length and width. The final model is deployed on a cloud-based application and integrated with an ontology model containing domain knowledge of the aquaponics system. The relevant knowledge about crop characteristics and optimal plant spacing is extracted from ontology and compared with results obtained from the final model to suggest further actions. The proposed application finds its significance as a decision support system that can pave the way for intelligent system monitoring and control.

REMOTE TECHNICAL VISITS: A POSSIBLE APPROACH TO THE ENVIRONMENTAL TOPIC IN TEACHING UNITS

The COVID-19 pandemic and the distancing measures required adaptations in the entire teaching structure. In this context, the objective of this article is to report remote visits carried out for students attending High School courses integrated to the Technical and Higher Education levels about environmental topics. The visits to five companies/organizations took place by means of a project prepared by undergraduate students attending the FMU Environmental and Sanitary Engineering course, aiming to provide them with a virtual presentation of their processes in the environmental area. The participants in the visits were 231 students from High School courses integrated to the Technical level from two public schools and 152 attending courses integrated to Higher Education at a private institution. Thus, in a dynamic way, it was possible to show socio environmental activities developed by the companies/organizations, regarding different theoretical-practical aspects inherent to sustainability, such as waste management, ecological sanitation, vegetable gardens in small spaces, aquaponics systems and the importance of stingless bees, among others. It is considered that the Remote Visits Project is within a scenario marked by the expansion of educational procedures, enriching both the academic experiences of the students directly involved in the Project and those of the other students participating in the visits, due to the reflections and learning processes provided by the immersion in applied sustainability models, thus promoting interdisciplinary knowledge, sensitization and diverse information pertinent to the environmental issues addressed in the visits.

Productivity of Fish and Crop Growth and Characteristics of Bacterial Communities in the FLOCponics System

Aquaponics (AP) and biofloc technology (BFT) systems rely heavily on bacterial communities to break down organic matter and cycle nutrients that are essential for fish and plant growth. The functional roles of bacterial communities in aquaculture systems are critical to their sustainable operation. Currently, the research on the combination of BFT and AP systems called FLOCponics (FP) is lacking, thereby hindering our ability to optimize their performance. Here, several characteristics (productivity of fish and crops, physicochemical properties of water, and bacterial community) in FP systems cultivating Japanese eel (Anguilla japonica) and leaf lettuce Caipira (Lactuca sativa) were compared to those in the BFT system. Additionally, the effect of fish density on the FP system was investigated. The results indicated that the FP system was more productive than the BFT system. Fish growth rate was highest in the FP system (52.6%), and the average body weight of eels was 168.2 ± 26.8 g in the FP system compared to 140.3 ± 27.0 g in the control (BFT, 5 kg/m2). However, increasing fish density resulted in lower growth rates, with a growth rate of 20.6% observed in the high-density (20 kg/m2) experimental group. The bacterial composition was also significantly different between the systems and fish densities, suggesting that bacterial communities may be closely related to the performance of the aquaponics system.

Adding Sustainability in Analytical Chemistry Education through Monitoring Aquarium Water Quality

This paper introduces a captivating topic for upper-level analytical chemistry capstone projects, focusing on aquarium water analysis. This provides a more comprehensive understanding of the role of analytical chemistry towards sustainability and its environmental, economic, societal and education dimensions. Regarding the crucial role of maintaining optimal aquarium water quality for the welfare of aquatic life, students are tasked with envisioning and executing the measurement of key parameters, including pH, ammonium, nitrite, and nitrate contents. This hands-on experience not only engages students in real-world applications, but also allows them to delve into essential analytical chemistry principles. They carefully select measurement methods, considering factors such as instrument availability, ease of use, precision and sensitivity requirements, sample size, and matrix effects. Besides fostering the acquisition of technical and soft skills, one notable aspect of this type of project is the exceptionally high student satisfaction. Furthermore, the project’s outcomes have proven to be significant predictors of learning achievements. Additionally, it lays the foundation for exploring potential designs of aquaponics systems and fosters interdisciplinary projects, expanding the practical applications in the field of chemistry education. Overall, these projects exemplify enriching and engaging educational experiences that empower students with valuable skills and knowledge while encouraging them to explore novel avenues in analytical chemistry.

Cress-loach coculture for improving the utilization efficiency of biogas slurry in aquaponic systems

Potential limitations to the direct application of biogas slurry (BS) as a substitute for chemical fertilizer in agriculture include nitrogen (N) and phosphorus (P) losses. However, an aquaponic system might serve as a new way to utilize biogas slurry completely. The following hypothesis was tested: the cress-loach coculture system will improve the N and P use efficiencies of cress, enhance biogas slurry utilization efficiency and crop yield, for which there will be an optimal ratio of cress and loach. An outdoor mesocosm experiment was carried out to test these hypotheses. In comparison to the floating-bed cress, the cress-loach coculture boosted the ability of cress to accumulate N and P by 56.75∼84.53% and 148.54∼232.44%, respectively. The coculture also increased the relative growth rate (RGR) and biomass of the cress by 60.93∼61.87% and 97.64∼151.46%, respectively. Other important roles of the cress-loach coculture system were reducing the accumulation of nutrients at the bottom (sediment), driving the circulation of nutrients in the water, and promoting the accumulation of nutrients in the cress. Additionally, the coculture system could make the most utilization of BS when the planting density of the cress and breeding density of the loach were 1.08 ± 0.005 g m−2 and 0.405 ± 0.004 g m−2, respectively. Our findings imply that a cress-loach coculture is an affordable, efficient, and environmentally-friendly approach for treating livestock biogas slurry. This approach can be immediately applied to livestock biogas slurry and result in excellent crop yields.

Production of Late Seedlings of Açai (Euterpe oleraceae) in an Aquaponic System with Tambaqui (Colossoma macropomum, Curvier, 1818)

Over the years, aquaponics has become a powerful technological tool that allows the sustainable production of food, integrating conventional fish farming with vegetable production. The present study evaluated the production of late seedlings of açai Euterpe oleraceae in an aquaponic system with tambaqui Colossoma macropomum. A total of 36 tambaquis with an initial average weight and length of 1086.75 ± 16.38 g and 38.49 ± 0.90 cm were distributed in 12 independent aquaponic units, totaling 3.62 kg m−3. The fish were fed three times daily with commercial feed at a rate of 3%. Three flooding levels of 5, 10 and 15 cm, with constant water flow through the hydroponic bed (0.5 m2), were evaluated, and a control-hydroponic bed with flooding levels of 10 cm was established, all in triplicate. In the 5 and 10 cm treatments, 3450 açai seedlings with an initial height of 12.3 ± 1.9 cm were used (575 per aquaponic units), while the 15 cm treatment contained non-germinated açai seeds. The control group did not receive açai seeds and remained empty. Analyses to monitor total dissolved solids (TDS), electrical conductivity, dissolved oxygen, temperature, pH, alkalinity, hardness, nitrogenous compounds, and phosphate levels were performed. At the end of the 30-day trial, the growth performance of tambaqui and plants was evaluated. Water quality was significantly (p &lt; 0.05) affected by different flooding levels. Electrical conductivity and TDS decreased with an increasing in flooding levels. The flooding levels significantly influenced (p &lt; 0.05) the concentration of total ammonia and nitrate between the treatments. The 5 cm flooding level showed the best plant development indexes for total height, aerial portion height, root height and aerial portion fresh mass. No significant differences (p &lt; 0.05) were observed in tambaqui growth performance. The aquaponic system proved to be effective in reusing fish waste (excreta and feed leftovers) generated in the system. The biotransformation of waste into nutrients allowed the growth of plants and nitrifying bacteria, which, through their metabolic pathways, ensured the purification and reuse of water, avoiding the discharge of this waste into the environment.

APPLICATION OF AQUAPONIC TECHNOLOGY IN GAPOKTAN BINA SEJAHTERA, AN EFFORT TO IMPROVE FOOD SECURITY

Aquaponics is an integration between fish and plant cultivation that benefits these two sectors. The development of aquaponics at the farm level can be an effort to increase food security. This community service activity aims to apply aquaponic leaf vegetable cultivation techniques, to optimize the facilities available at Gapoktan Bina Sejahtera (fish ponds). Activities carried out by counseling methods, training and demolots to farmers regarding the cultivation techniques of leaf vegetables and red tilapia with an aquaponic system. During the activity, monitoring was also carried out by a team of service lecturers, assistance by student teams and evaluation through pretest and posttest. This community service activity is able to provide new experiences, and increase farmers' knowledge and skills in cultivating red tilapia and leaf vegetables with an aquaponic system.

AQUAPONICS IN BRAZIL: REVIEW AND SURVEY ON WASTE MANAGEMENT PRACTICES

Aquaponics is a food production technique that may be applied in the context of urban agriculture to help achieve food security and promote sustainable agriculture and production patterns, among other Sustainable Development Goals. Brazilian population is large and highly concentrated in urban areas and might benefit from this technique. Similar to any other production activity, aquaponic systems generate wastes that must be properly managed, but until now no study focused on waste generated on such systems or on management practices adopted by Brazilian producers; the goal of this article was to address both of these gaps. A systematic review identified waste streams generated on aquaponics, while management practices were seldom mentioned and addressed. A survey on producers located in 17 of the 27 Brazilian federal units helped confirm sludge, packaging waste, dead fish and unusable plant fractions as typical waste streams. It also identified a lack of concern for a more in-depth assessment of such streams to improve management practices, which tended to gravitate toward adequate and inadequate disposal. Finally, the article proposes management practices for each waste stream, drawing from strategies foreseen in Brazilian National Solid Waste Policy.