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The present study aimed to evaluate an aquaponic bioeconomic model integrating the cultivation of tambaqui (Colossoma macropomum) with coriander (Coriandrum sativum) at different densities of 32, 72, 128, and 512 cells m−2 for 19 days. The hydroponic bed was configured on a bench with a capacity of 100 L (1.62 m-long, 0.72 m-width, and 0.1 m-depth) and was coupled to a plastic tank with the fish. The coriander seeds were irrigated for four days until germination, when they were transferred to the hydroponic beds. Two hundred forty tambaqui juveniles (113.5 ± 0.15 g and 19.6 ± 0.20 cm) were distributed in 12 tanks (1000-L capacity) in aquaponic units, totaling 20 fish per unit. The fish were fed commercial feed (36% protein and 7% lipids), and water quality variables were monitored daily. At 5, 10, and 15 days after transplanting to the hydroponic bed, the leaf number (LN) and plant height (PH, in cm) of the coriander were determined. Additionally, total fresh mass (TFM, in g), leaf fresh mass (LFM, in g), root fresh mass (RFM, in g), total dry mass (TDM, in g), leaf dry mass (LDM, in g), root dry mass (RDM, in g), leaf length (LL, in cm), root length (RL, in cm), yield of total fresh mass (YTFM, in kg m−2), and the nutritional composition of macro and micronutrients were determined, as well as fish growth performance. A density of 512 cells m−2 reduced the electrical conductivity (0.097 ± 0.001 dS m−1) of the water. The pH, dissolved oxygen, and temperature did not differ significantly between the densities. The total ammonia nitrogen (28.81 ± 2.26 mg L−1) and nitrate (51.07 ± 0.81 mg L−1) concentrations were greater at a density of 32 cells m−2. At the end of the 19-day period, the fish growth indices did not significantly differ (p > 0.05) as a function of coriander cultivation density. Density significantly influenced coriander growth. All variables (PH with root, LL, RL, LFM, TFM, LDM, TDM, RFM, RDM, and YTFM) were significantly influenced (p < 0.05) as a function of cultivation density. YTFM (1.82 ± 0.45 kg m−2), PH (30.39 ± 0.61 cm), and LL (16.62 ± 0.53 cm) were significantly higher (p < 0.05) at a density of 512 cells m−2. RL was significantly higher (p < 0.05) at densities of 72 and 32 cells m−2, of the order of 15.98 ± 0.43 and 18.79 ± 1.01 cm, respectively. Boron was significantly greater at a density of 512 cells m−2 (39.70 ± 1.04 mg kg−1) than at 32 cells m−2 (29.93 ± 4.66 mg kg−1). Similarly, sodium was significantly more abundant at a density of 512 cells m−2 (5975.54 ± 783.82 mg kg−1) when compared to the densities of 128 and 72 cells m−2, which were 4179.97 ± 287.31 and 3760.60 ± 224.31 mg kg−1, respectively. Aquaponic production in the equatorial Amazon region accelerated, and the optimal density for coriander integrated with tambaqui without compromising plant growth performance was 128 cells m−2. [Display omitted] • First report on the integrated cultivation of tambaqui (Colossoma macropomum) with coriander (Coriandrum sativum L.). • Coriander significantly reduced the total ammonia in the water. • Coriander densities caused significant changes in the electrical conductivity. • Density impacts the nutritional composition of coriander. [ABSTRACT FROM AUTHOR]

In advancing towards more sustainable aquaculture, the inclusion of insect meals in aquafeeds has significant potential to increase circularity and reduce environmental impacts, especially in aquaponics. Nevertheless, there is a lack of information regarding the environmental performance of these innovative feeding and management solutions. This study assessed the environmental impact associated with the dietary inclusion of Hermetia illucens (HI) meal (0%, 6% and 12%) in diets for rainbow trout (Oncorhynchus mykiss) reared in a low-tech aquaponic system characterised by nine independent experimental units (6.06 kg/m3 of fish and 14 strawberry plants per unit). A cradle-to-gate attributional life cycle assessment model was used to consider the impacts related to the whole aquaponic system (AQ-FISH) and those only related to the production and use of the aquafeed (AQ-FEED). The impact categories were 100-year global warming (kg CO 2 -eq) – with (GWP_LUC) and without (GWP) the emissions associated with land-use change (LUC), acidification (AP, g SO 2 -eq) and eutrophication (EP, g PO 4 -eq) potentials, cumulative energy demand (CED, MJ), land occupation (LO, m2/y) and water scarcity (WS, m3-eq). The functional unit was a 1 kg live weight increase of rainbow trout. Data originated from a previous 76-d fish performance trial. Data regarding HI meal were derived from an interview with the manufacturer. An economic method was used to partition the impacts between HI meal, HI fat and the frass (exhausted substrate). The effect of the HI meal inclusion level on the AQ-FISH and AQ-FEED impact values was tested using one-way analysis of variance. A 1 kg live weight increase of rainbow trout reared in the aquaponic system (AQ-FISH) produced 15.6 kg CO 2 -eq (GWP), 18.3 kg CO 2 -eq (GWP_LUC), 67 SO 2 -eq and 55 g PO 4 -eq and used 354 MJ, 3.5 m2/y and 311 m3-eq. The dietary inclusion of HI meal did not affect the AQ-FISH results, except for CED (+2%–5%). When considering the impact resulting from feed production (AQ-FEED), the inclusion of HI meal did not affect GWP_LUC, AP, EP and LO, but it negatively affected GWP (+13%–26%) and CED (+34%–68%). Results from AQ-FISH and AQ-FEED scenarios showed low sensitivity to the methodological choices. Overall, our findings suggest that general improvements to reduce the environmental impact associated with rainbow trout production in aquaponics should be concurrently directed towards both the system setting and management, as well as towards the HI meal production process, with a particular emphasis on enhancing energy efficiency. To minimise potential trade-offs, especially from an environmental perspective, future studies should prioritise the investigation of energy use and greenhouse gas emission associated with feed production. This requires a thorough evaluation of all changes in the diet formulation resulting from the inclusion of a new ingredient. • LCA of fish meal vs. insect meal (IM) in diets for trout in aquaponics was assessed. • IM impact increased from organic matter to system expansion to economic allocation. • The impact of trout production in aquaponics was not affected by insect meal inclusion. • 12% insect meal inclusion increased feed-related energy use and GHG from 13 to 68%. • Trout production impacts were robust to sensitivity analysis (±3%). [ABSTRACT FROM AUTHOR]

As the world population continues to grow, alternative protein sources must be sought to meet increased protein needs and avoid the detrimental effects of traditional protein production. Microbial proteins (MP) are a low-carbon footprint alternative suitable for manufacturing food and feed. Bacterial-based MP can be produced at moderate costs using agro-waste, which is already utilised by anaerobic digestion (AD) plants to produce biogas and fertilisers. At present, there is the opportunity to turn existing AD plants into biorefineries for bio-based products like MP destined for fish feed. In this work, we evaluated the feasibility of biogas production coupled with MP production in the same medium-sized European biogas plant through mass and energy balances and basic economic assessment. The liquid phase rich in volatile fatty acids resulting from agro-waste fermentation was used to obtain MP by mixed cultures in a continuous stirred tank reactor, with the highest VSS productivity (1.21 g/L day) obtained at hydraulic retention times of 2–3 days. The obtained MPs were rich in proteins (74.0% of TVS), PHAs (22.5%) and essential amino acids, useable as feed ingredients in aquaculture. An initial economic analysis showed that the production of 590 tMP/year could yield a break-even price of 1300 €/t of MP, taking into account the investments in the new technology and additional operating costs. This analysis illustrates the competitiveness of a combined plant when evaluated against established market benchmarks and highlights a promising prospect for the expansion of MP production capacity. [Display omitted] • MP were produced in a bioreactor with a maximum productivity of 1.21 g/L day. • MP were rich in proteins (74%), polyhydroxyalkanoates (22.5%), essential amino acids. • Plants for biogas production could be upgraded to produce MP for aquaculture. • The calculated break-even point for combined MP-biogas plants is 1300 €/t for MP. • A medium-sized biogas plant has the potential to host cost-competitive MP production. [ABSTRACT FROM AUTHOR]

Aquaponics promises a more sustainable approach to food production by repurposing waste from aquaculture for the production of crop plants. Previous life cycle assessments have been published on the environmental impacts of coupled aquaponics using recirculating aquaculture systems, however, impacts from decoupled biofloc aquaponics systems remain unknown. Decoupled systems offer many operational advantages over coupled systems, and the objective of this study was to use life cycle assessment to quantify their environmental impacts. Data from a multi-greenhouse aquaponics system was collected over a one-year period to generate a life cycle inventory. A previously published mass balance model was also used to analyze alterative operational scenarios. Both avoided burden and mass allocation approaches were considered given the high sensitivity of the model toward the former. Results showed that electricity, heating fuel, and feed made up 40%, 22%, and 24% of global warming potential (GWP), similar to other aquaponics studies. These inputs similarly dominated cumulative energy demand. A switch to renewable electricity sources could reduce GWP by over 40% in scenario analysis. Eutrophication impacts of the decoupled biofloc aquaponics system ranged from 8.93 × 10−3 to 5.27 × 10−2 kg N-eq per kg fish depending on the scenario. While at least 10% lower than aquaculture alone, these rates were over four times higher than coupled aquaponics due to discharge of nutrient-containing waters after plant production. Efforts to balance fish and plant production are especially critical in decoupled systems, as is re-use of post-plant effluent. These results show that careful consideration of operational decisions is important when trying to minimize the environmental footprint of decoupled aquaponics systems. [Display omitted] • Aquaponics had >10% lower eutrophication impacts than aquaculture alone. • Electricity, heating, and feed dominated energy and global warming impacts. • Measured direct greenhouse gas emissions were <2% of total emissions. • Eutrophication impacts of decoupled aquaponics >4x higher than coupled. • Results were sensitive to co-product allocation method. [ABSTRACT FROM AUTHOR]

This article reviews current literature published on aquaponics, a growing technology which uses aquaculture effluent to grow plants. Aquaponics offers a solution to several sustainability issues, such as, limited water availability, environmental pollution, increasing fertilizer cost, and depletion of fertile soils. The commercial and scientific application of aquaponics is growing; however, there is yet to be a review which holistically analyses scientific literature to indicate what type of system performs optimally, what will be the most dominant horticultural challenges as the commercial sector expands, and what direction of aquaponic research will be most impacting. This review analyzed over 529 publications on aquaponics, from 1978 to 2018. Through a systematic process, 257 of the most constructive publications were further analyzed and organized into varying groups based on content. The review found that in the past three 3 years, over 160 scientific articles have been published on aquaponic technology, detailing numerous trends, technological advancements and challenges associated with the system, consolidating the expansion of aquaponics and the need for a review. From publications investigating trends, it was found that decoupled aquaponic systems are becoming increasingly popular over coupled aquaponic systems, a deep water culture hydroponic component and media bed component are optimal for commercial and research applications, respectively; Tilapia and dark leafy vegetables are the most successful species used and Nitrospira may play a more important role in the aquaponic nitrification process than expected. From publications investigating challenges, it was found that commercial aquaponics will face difficulty growing high value flowering crops such as sweet peppers, tomatoes or cucumber, as a result of suboptimal nutrient ratios in aquaponic solution, specifically the reduced K+, Mg+, and Ca+. Holistically, it was found that the most important aspect of aquaponics that needs future research is the role plant promoting microbes play in nutrient uptake. Considering plant growth promoting microbes are likely the cause of aquaponic plants being able to achieve yields similar to that of hydroponics, despite nutrient levels being significantly lower, future research in this field can be paramount to the beneficial use of microbes in all plant production systems. • Publications on aquaponics have increased exponentially in the past 3 years. • Aquaponic systems are moving from coupled to decoupled systems. • Tilapia paired with dark leafy greens are the commonly used species in aquaponics. • Plant growth promoting microbes play a vital role in the success of aquaponics. • The most prominent horticultural challenge in aquaponics is suboptimal nutrients. [ABSTRACT FROM AUTHOR]

Abstract Recirculating aquaculture system (RAS) effluent has a high concentration of nitrogen, which can be a valuable asset as fertilizer for agricultural use in the vicinity of the RAS. A novel fully-automated experimental set-up of 24 lysimeter-plots was used to determine the optimal irrigation rate for cucumber plants fertigated with RAS effluents of three different nitrogen concentrations. Three RASs were stocked with 7, 14 and 21 kg of barramundi (Lates Calcarifer), which were fed 1.75% of their body mass daily. Then, 10% of the water in each RAS was exchanged daily, resulting in three nitrate–N concentrations of approximately 30, 60 and 90 mg/L. A synthetically fertilized control treatment was kept at 60 mg/L nitrate–N, and the other essential plant nutrients were kept at the same concentration for all treatments. The water from these four sources was then used to irrigate six plots per nitrate–N concentration treatment, at a rate of 1–6 times the amount transpired, which was measured in an automated fashion by the experimental set-up. Two yield response to nitrogen fertigation models fit well to the measured data, and although they led to different conclusions in terms of optimal fertigation can be a useful tool for decision support. The nitrogen use efficiency dropped with increased fertigation, from about 80% to 55%, and more fertigation led to an exponential increase in drainage and gaseous emissions of nitrogen. The observed data can be used to optimize irrigation for each nitrogen concentration, but the values are highly dependent on climate, plant type, and root zone characteristics, demonstrating the need for more inclusive modelling. Determination of how to optimally make use of RAS effluent water and the comparison with synthetic fertilizer can lead to the development of simplified protocols concerning integrated aquaculture agriculture systems, making it accessible to a wider range of growers. Graphical abstract Image 1005 Highlights • Plant yield from RAS effluent is comparable to that of synthetic fertilizer. • Optimal irrigation rates were determined for different nitrogen concentrations. • Exponential increase of nitrogen emissions beyond optimal application was observed. [ABSTRACT FROM AUTHOR]

Abstract Aquaponics is considered as a promising approach to mass produce both fish meat and vegetable at high rates without discharge pollutants. A novel aquaponics system is proposed to control water quality and enhance nutrition efficiency with high rate immobilized biofilm units, including mass-bio system (MBS) and fiber biofilter (FB), installed between upstream hydroponics units, which are composed of the media filled beds (MFD) and nutrient film technique (NFT), and downstream aquaculture unit for fish rearing. A pilot test was conducted over 130 d to characterize the performance of proposed system which converted residual nutrients from aquaculture unit into ammonium and nitrate at balanced ratio for aquatic plant growth and then removed residual ammonium or/and nitrite to ensue recycled water quality for fish rearing. The kinetics of organic matter removal and nutrient conversion in hydroponics unit and immobilized biofilm units were determined via batch assays over 24 h in the system. The estimated daily pollutant increments for TAN, NO 2 −-N, NO 3 −-N, TN, DTP and TOC in the system were 0.28, 0.17, 0.20, 0.64, 0.56 and 2.19 mg/L, respectively. The results demonstrated that total ammonia nitrogen (TAN), nitrite (NO 2 −-N), nitrate (NO 3 −-N), total nitrogen (TN), dissolved total phosphorus (DTP) and total organic carbon (TOC) were maintained at low levels in the system for a long-term. Aquatic plants in MFD and NFT contributed to the removal of TAN, NO 2 −-N, NO 3 −-N, TN and DTP. The removal efficiencies of MFD versus NFT for TAN were 71.4% vs 43.5% for TAN and 62.5% vs 52.3% for DTP. MBS and FB performed the removal of TAN, NO 2 −-N and TOC. The 24 h removal efficiencies of TAN, NO 2 −-N and TOC were 71.8%, 58.5% and 3.7% for MBS and 15.7%, 7.7% and 27.2% for FB. Graphical abstract Image Highlights • A novel process of aquaponics system combined with immobilized biofilm units was tested at pilot scale. • This system controlled water quality of aquaponics for fish rearing over 130 d. • Aquatic plants in media filled beds showed better nutrient removal than nutrient film technique. • More total ammonia was removed by immobilized biofilm units than hydroponics units. [ABSTRACT FROM AUTHOR]

Efforts to reduce the environmental burden of agri-food systems have fostered technological advances to enable a transition towards more sustainable production and diets. Such a transition is only possible if consumers are willing to accept foods produced using novel technologies. Previous research on consumer acceptance has generally focused on individual technologies in isolation, rendering comparisons across studies difficult, and mostly considered average acceptance without devoting attention to individual differences among consumers. Additionally, available data overwhelmingly pertained to European and North American consumers, whereas much less is known about consumer perception in non-Western countries. Against this backdrop, this study examined consumer acceptance and perception of a wide range of novel, sustainable food technologies in four countries (Australia, India, Singapore, and the USA, N = 2494 in total) using survey methodology. For each technology, willingness-to-consume (WTC, operationalized as expected frequency of consumption), emotional associations, and situational appropriateness responses were collected. All measures revealed major differences in consumer perception of novel food technologies, identifying three groups: 1) technologies with high consumer acceptance comprising vegetables from urban farming and vegetables packaged in a modified atmosphere; 2) technologies with medium consumer acceptance comprising fish reared in aquaponics systems, plant-based alternatives to meat and dairy, and gene-editing; 3) technologies with low consumer acceptance comprising insect ingredients, cell-cultured meat and cell-cultured fish. Technologies in the high acceptance group were perceived as healthier and apt to move one's diet in a more sustainable direction, whereas consumers had issues associating specific benefits to the less accepted technologies. Cross-cultural differences were identified. Most notably, Indian consumers responded more positively to all novel food technologies, especially compared to consumers in the US and Australia. Finally, four pan-national consumer segments were identified based on their overall patterns of acceptance towards novel food technologies. The segments varied primarily in terms of baseline WTC (low, medium, and high), indicating that consumers tended to accept or reject novel food technologies regardless of their nature. The segment characterized by a high acceptance included only about a fifth of the consumers, showing that WTC towards novel food technologies for most consumers ranged from moderate to outright rejection. Collectively, the findings of this study suggest that consumers' general skepticism regarding technologies in the food domain remains a significant challenge towards achieving more sustainable diets. • Consumer perception of 12 novel sustainable technologies in four countries (N = 2494). • Major differences in willingness-to-consume (WTC) between novel food technologies. • Highest WTC for urban farming, aquaponics, and active packaging. • Lowest WTC for insects-based products and cell-cultured meat and fish. • Four global consumer segments identified and characterized. [ABSTRACT FROM AUTHOR]

Aquaponics is an integrated system in which the water containing fish waste is used as a nutrient source for plant production in a closed recirculation system. In this study, tilapia ( Oreochromis niloticus ) and pak choi ( Brassica chinensis ) culture was tested using two techniques: 1) Root floating (RAFT), and 2) Dynamic root floating (DRFT). Water quality parameters, total ammonia nitrogen, nitrate nitrogen, nitrite nitrogen and phosphate were measured. At the end of the experiment, fish and plants were weighed and the required electric power consumption was calculated. There was no significant difference observed between the effect of each treatment group on either tilapia or pak choi production. Tilapia productivity was 1.69 ± 0.22 kg/m3 and 1.71 ± 0.23 kg/m3 and pak choi yield was 7.43 ± 1.23kg/m2 and 7.32 ± 0.76 kg/m2 for the RAFT and DRFT, respectively. Water quality parameters were within the recommended range for the tilapia culture while pH and conductivity were out of range for the pak choi culture; nevertheless, plant production was good. Total ammonia nitrogen and nitrite nitrogen did not reach concentrations that could impede tilapia growth. The DRFT allows the elimination of active aeration in hydroponic systems for tilapia and pak choi production during most of the cycle, reducing the electric power consumption to 10.3% and electricity costs to 11.4% by using a nature-based solution. [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]

Aquaponics is the cultivation form that integrates aquaculture with hydroponics to nurture plants and fish simultaneously. And aeration plays an important role in its sustainable operation, as well as economic and environmental feasibility. In this study, two patterns to reduce aeration intensity, i.e., semi-aeration (SA) and intermittent aeration (IA) were used to improve the economic and environmental benefits of media-based aquaponics. Results showed that SA aquaponics, in which the energy efficiencies on culturing fish and crop were improved respectively by 78.20% and 77.61% compared with Control, had the potential to obtain higher economic benefits. Although both SA and IA could save half of the aeration cost by reducing aeration flux and time respectively, the product yields in SA weren’t impaired seriously while in IA aquaponics they were. And the nitrogen utilization efficiency (NUE) of SA aquaponics was 11.3% higher than that of IA aquaponics, mainly attributed to the more stable dissolved oxygen concentration in SA. Better water quality was obtained in IA aquaponics, however, it was achieved at the cost of higher N loss (mainly in the form of N 2 ), which subsequently reduced the potential for further improvement of NUE. Both SA and IA could considerably reduce GHG emissions from aquaponics, due to lower energy requirement. IA aquaponics showed the lowest N 2 O emission, but the primary source (over 97%) of greenhouse gases (GHG) emissions from aquaponics was off-site indirect CO 2 emission. Taking productivity and environmental impact into consideration, semi-aeration was believed to be a better choice when reducing aeration. [ABSTRACT FROM AUTHOR]

Highlights • Technical problems hinder the industrialization of conventional aquaponics. • Microbial system could efficiently degrade wastes and improve the water quality. • Novel aquaponics increases stocking density and produces value-added products. • Microbial system is expected to promote the sustainable development of aquaponics. [ABSTRACT FROM AUTHOR]

Recirculating aquaponics systems (RAS) are known to provide an economic alternative for producing healthy foods to address health disparities and food scarcity in abandoned urban areas (food deserts) with limited water and land resources. This study integrated design and operational data into a techno-economic analysis (TEA) to study the profitability of a commercial-scale tilapia-lettuce aquaponics system in the U.S. Midwest. An operational pilot-scale plant was used to obtain the necessary data for the TEA modeling. A mid-size commercial system with a 5300 L fish tank and a 62–63 m2 plant grow bed space was considered for the analysis. The initial investment cost of the system was $69,230–69,600, with the greenhouse constituting 42% of the cost. The annual operating expense was $33,100 - $33,300, with labor being the major contributor (52%). Sensitivity analysis was performed on land, equipment, feed, utility costs and revenues from fish and lettuce, which identified the labor and greenhouse costs as prime factors controlling the profitability. The market value of the lettuce and its grow space used contributed to the profitability of the studied RAS from the revenue side. A cash flow analysis showed that the system can be profitable, offering a positive net present value (NPV) of $9000 - $12,220. Automated water quality monitoring further reduced labor costs, increasing NPV to $52,220 – $55,545. The TEA, augmented with process data and an uncertainty-based financial performance evaluation identifying key plant parameters, may serve as a framework for evaluating the economic viability of similar food production systems in different locations. • Aquaponics system is a sustainable urban food production alternative. • Techno-economic analysis found aquaponics systems (1400 gal fish tank) are profitable. • Labor and facility costs identified as controlling factors to profitability. [ABSTRACT FROM AUTHOR]

Productive cities are one of the most important ways to achieve urban sustainable development. In the comprehensive production function, food production is the most basic function and should be defined as a priority. Considering the characteristics of buildings and the limitations of the urban environment, aquaponics is a safe and healthy green technology that protects the ecological environment and that has high potential to combine urban buildings and plant cultivation technology. Research on aquaponic systems has become increasingly mature, but some new problems that cannot be ignored, such as low nitrogen utilization efficiency, high aeration cost and noise problems, and unreliable water quality. In this study, a new aquaponics system model (photosynthesis reoxygenation aquaponics, PRO-AP) was proposed, and it was expected that the structure of the system can be adjusted by adding macroalgae to improve the existing problems in aquaponics. An experiment was conducted to preliminarily explore the feasibility of the proposed mode of operation. Spirogyra was added to the aquaponics system, and the DO, pH, TDS, EC, ammonia nitrogen and removal of the key nutrients from the systems were monitored during the operation. The results showed that the dissolved oxygen content in the system increased markedly and that the pH drop caused by nitrifying bacteria could be balanced when Spirogyra was irradiated with effective light. In addition, Spirogyra played a certain role in biofiltration in the aquaponic system, which reduced the values of TDS and EC, the contents of NH 4 +, NO 3 − and PO 4 3− also decreased, and the nitrite content first increased and then decreased after a period of time. Finally, under the ratio of fish and vegetables in this experiment, the existence of Spirogyra did not create a negative image of the yield and root system of vegetables in aquaponics systems. The results showed that the aquaponic system with macroalgae has a stronger self-regulation ability. PRO-AP is an effective method in urban food production and is a very promising mode of production in the sustainable development of productive cities. [Display omitted] • New potential productive model-productive double-skin facades (PDSFs) were constructed. • New aquaponics system model PRO-AP was proposed. • Based on the characteristics of PRO-AP, the quality of food production was improving in urban environments. • PRO-AP has potential to become a safe, healthy, ecological, and environmentally protective green technology. [ABSTRACT FROM AUTHOR]

Aquaponics is a food production system that aims higher sustainability by integrating advantages gained from aquaculture and hydroponic production. Aquaponics aims to mimic the biological process that happens in the natural environment in a controlled production system. As it can be applied to small scales, aquaponics is considered an important alternative for urban regions, which have low availability of agricultural land and water resources. Furthermore, the advantage is that it is located close to final consumers. Aquaponics has been labeled as an environmentally friendly food production system, but its demand for energy and materials cast doubt on its sustainability. A systemic understanding of aquaponics production systems is needed to determine the magnitude and balance between its potentialities and constraints, in which emergy synthesis appears as a powerful tool for this purpose. This study applies emergy synthesis to assess the sustainability of two different (scale and marketable products) urban aquaponics farms in Brazil, but differently from other emergy studies, ecosystem services and disservices are included in the analysis as an attempt to represent the system performance holistically. Results show that the type of materials used in aquaponics infrastructures has the highest influence on total emergy demand. Surprisingly, electricity and fish feed showed a low influence on the total emergy, reinforcing the idea that aquaponics systems have a more efficiency feeding management than traditional aquaculture systems. Besides producing vegetables and fish, the inclusion of ecosystem services highlights the importance of aquaponics for educational and tourism purposes. Finally, the obtained indicators from modeling scenarios revealed that replacing the water source and some materials deserves priority attention to increase the sustainability of urban aquaponics farms. [ABSTRACT FROM AUTHOR]

An effective strategy for the nutrient recovery from fish sludge in aquaponics is critical for cleaner and sustainable production. The modified biological aerated filter (MBAF) is applied as an effective approach for the collection and conversion of fish sludge to nutrients in one reactor. Nutrient conversion would be synchronized during the filtration of fish sludge if the filtration time is sufficient, which is significant for the nutrient recovery. To test the hypothesis, in this study, modified biological aerated filters filled with polyurethane sponge media were equipped to the fish tank of a pilot aquaponic system to examine the effect of extended filtration time on the nutrient conversion with respective extended filtration time of 11 d (MBAF-1) and 36 d (MBAF-2). The MBAF-2 collected more fish sludge than the MBAF-1 by ca. 57.0%. The duration time of filtration was limited by total ammonia nitrogen in the fish tank. Most of the fish sludge was transformed into soluble nutrients in both MBAFs. In MBAF-2, higher macronutrient and micronutrient concentrations were achieved than that in MBAF-1, especially N and P (4.0 and 2.1 times greater, respectively). MBAF-2 had a high nutrient recovery efficiency (NRE), namely 22.6% for N, 62.1% for P, 17.1% for K, 39.7% for S, 18.5% for Mg and 79.1% for B, respectively, indicating the N and P recoveries in MBAF-2 were 6.1 and 3.0 times of those in MBAF-1, respectively. Based on the results, an optimized aquaponic system with two-stage MBAFs is proposed, and each stage consists of two filter columns to conduct the extended filtration of fish sludge and the nutrient conversion alternately. [Display omitted] • Modified biological aerated filter was applied for nutrient recovery from fish sludge. • The effect of two extended filtration time on the nutrient recovery were compared. • The extended filtration time of 36 d achieved higher sludge amount by ca. 57.0%. • The nutrient recovery efficiency of 22.6% for N and 62.1% for P were achieved. • An optimized aquaponics with modified biological aerated filters was proposed. [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]

This study investigates the upcycling of nutrients in anaerobic digestate via algal biomass to zooplankton which is a natural fish feed. There are no published studies, to the authors' knowledge, on the viability of growing zooplankton on digestate-grown algae. Here, the viability of digestate-grown Chlorella sorokiniana as a feed for the large-bodied generalist zooplankter, Daphnia, was tested. It was found that Daphnia fed with digestate-grown C. sorokiniana led to 1.5- to 14-fold greater Daphnia population growth than Daphnia fed with Ankistrodesmus sp., an established feed. A sterol analysis of C. sorokiniana found 4–6 mg/g of the sterol, ergosterol, and nearly double the α-linolenic acid content of Ankistrodesmus. Sterols and α-linolenic acid are often-limiting nutrients in Daphnia diets. Other factors hypothesized to influence nutrient transfer from algae to Daphnia were also tested, including algal feed concentration, sterol supplementation, and the presence of digestate bacteria in the algal feed. The presence of bacteria and exogenous cholesterol had no significant impacts on Daphnia growth. The higher feed concentration (5 mg C/L) led to 3 times higher Daphnia growth than the low feed concentration (1.5 mg C/L) even though the latter concentration has frequently been used by other researchers. Finally, it was determined that the feed conversion ratio of algae to Daphnia fell in the range of 0.19–0.31 and that trophic transfer of carbon was 25–28% while that of nitrogen was 29–34% in this un-optimized system. These values compare favorably to livestock feed conversion efficiency but additional losses will occur when Daphnia are fed to fish. These results show that cultivation of Daphnia on digestate-grown algae is technically feasible. • The feasibility of feeding Daphnia with digestate-grown algae was established. • Digestate-grown Chlorella led to 1.5–14X faster Daphnia growth than standard feed. • Wastewater bacteria present in algal feed had no impact on Daphnia. • 25–28% C and 29–34% N conversion efficiencies from algae to Daphnia were achieved. [ABSTRACT FROM AUTHOR]

Rice-crab co-culture (RC) is an environmentally friendly, agri-aquaculture technique, however, its knowledge about soil nutrients status and their composition in rice grain has remained unexplored. The aim of current study is to explore this deficiency. Thus, a field survey and a field experiment were combinedly carried out at Panjin City, China. The field survey with 16 fields each for rice-monoculture (RM) and RC was conducted without influencing conventional cultural practices. The field experiment was conducted with four treatments: rice-monoculture (RM), 3000 crabs ha−1 without feed (RC3000), 6000 crabs ha−1 with feed (RC6000), and 12,000 crabs ha−1 with 2 × feed (RC12000). Results showed an increase in soil nutrients and improved nutrient accumulation in rice with the RC system. Soil organic carbon, macronutrients (nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg)), microbial biomass carbon, and nitrogen, micronutrients (copper, zinc (Zn), and manganese) were improved. From the field survey, results indicated significant improvement in grain TN (9.4%), calcium (Ca, 22.1%), Mg (7.1%), and Zn (26.1%) in RC system compared to RM system. In field experiment, the concentrations of Ca, Mg, and Zn were increased as follows: i) Grain Ca in RC3000 (23.9%) and RC6000 (17.1%), ii) Mg in RC3000 (12.6%), RC6000 (16.3%), and RC12000 (11.8%), iii) Zn in RC3000 (10.8%), RC6000 (5.7%), and in RC12000 (14.8%). The RC system has also improved nutrients translocation from soil to plant biomass that was the key reason to increase nutrient composition in rice. The results implied that the improvement of rice yield was by the increased nutrient in soil and the higher nutrient translocation capacity from soil to rice under the proper culturing crab density. Image 1 • Rice-crab co-culture (RC) system improves soil and plant nutrient status. • Nutrients acquisition was improved by enhanced translocation from soil to the plant. • Adaptation of the RC system can help to reduce the chemical fertilization (CF). • Proper feed management can influence nutrients cycling and CF dose recommendation. [ABSTRACT FROM AUTHOR]

A vital goal of cleaner production involves developing agricultural production systems capable of ensuring sufficient yields of highly necessary foods to meet the increasing needs of the global population while minimizing the associated economic and ecological costs. Integrated agri-aquaculture systems (IAAS) offer a number of advantages for sustainable agriculture, including water reutilization, discharge mitigation, and increased profitability by leveraging the symbiotic relationship between organic waste, bacterial mineralization, and plant filtration. The aim of this study was to assess the production of two food items of global socio-economic importance cultivated at different salinities: Pacific white shrimp (Penaeus vannamei) and tomatoes (Solanum lycopersicum L.) grafted to salinity tolerant wild tomatoes. Pacific white shrimp were cultured at a density of 125 organisms/m3 and tomatoes at a density of 3 plants/m. The shrimp growth test consisted of three salinity levels: 2, 4, and 6 g/L. The corresponding tomato salinity treatments were conducted using shrimp water effluents; Steiner's universal nutrient solution (SNS) was used for the control treatment. The experimental period lasted 175 days. The highest tomato production (77.46 t/ha) was attained with SNS, with no significant difference from the salinity of 2 g/L. Shrimp final mean weight, survival, and production were higher at the 6 g/L salinity; and all the other zootechnical parameters decreased with lower salinity. When compared with the hydroponic system using a cost-benefit analysis (CBA), the production costs associated with the IAAS were lower primarily because of the reduced (or null) costs of fertilizer, and irrigation water. When grafted plants were used, the salinity tolerance of the commercial hybrid increased and shrimp could be cultured at appropriate salinity to facilitate osmoregulation. Chemical fertilization requirements were reduced and acceptable yields were obtained for the tomato crop by grafting to salinity-tolerant rootstocks. • Saline-tolerant Guasave wild tomato was 100% resilient to 9 g/L salinity. • Shrimp and grafted tomato in 4 g/L salinity were stress tolerant and productive. • Salinity levels >4 g/L increased blossom-end rot by 40% even with grafted tomato. • Aquaponics yield budgets must consider costs of biofiltration and nutrients recovery. • Waste discharge and water supply concerns may be mitigated with aquaponics. [ABSTRACT FROM AUTHOR]

With high productivity and low land and water use, controlled-environment agriculture (CEA) like aquaponics and hydroponics has become a promising solution to feed the rapidly growing global population. However, both aquaponic and hydroponic systems require high energy input, leading to potential environmental burdens. This cradle-to-gate life cycle assessment (LCA), for the first time, compared the environmental performance, on an economic basis, of aquaponics and hydroponics with identical system design in Indiana, US. For a one-month cultivation period, tilapia and six vegetables produced in the aquaponic system had almost twice the total value of the vegetables from the hydroponic system. Aquaponics produced 45% lower endpoint environmental impact than hydroponics. Electricity use for greenhouse heating and lighting, and water pumping and heating contributed to the majority of the environmental impacts of both systems, which was followed by the production of fish feed and fertilizers. However, changing the energy source from coal to wind power could make the hydroponic system more environment-friendly than the aquaponic system. This LCA study can provide CEA farmers with the groundwork to reduce the environmental cost of their production. Image 1 • Aquaponics and hydroponics were operated with identical system design in Indiana. • Environmental performance of both systems were compared via LCA on an economic basis. • Fresh produce from aquaponics had higher economic value and lower environmental impacts. • Electricity use for greenhouse operation was the environmental hotspot of both systems. • Using wind energy could make hydroponics more environment-friendly. [ABSTRACT FROM AUTHOR]

Aquaponics is known to be one of the most efficient agriculture production systems by far; however, limited quantitative data are available on the level of efficiency, particularly in comparison to its counterpart, hydroponics. This study compared aquaponics with hydroponics to assess nitrogen (N) and phosphorus (P) distributions, N- and P-use efficiency (NUE and PUE), and potential environmental impacts. Cherry tomato, basil, and lettuce were cultured in recirculating tilapia (Oreochromis niloticus)-based aquaponic or stand-alone hydroponic systems over a 3-month period. N and P mass balances were developed by using N and P concentrations in fish feed, solid waste, wastewater, fish biomass, and plant biomass for aquaponic systems, and chemical fertilizer, wastewater, and plant biomass for hydroponic systems, which were to estimate N and P loss from each system via denitrification and P precipitations, respectively. In aquaponics, 59–70% of total N input was estimated to be lost via denitrification (45–50%), wastewater (14–20%), and solid waste (0.7–2%) and 30–41% was assimilated into biomass (21–24% fish; 9–17% plants). In hydroponics, 76–87% was estimated to be lost via denitrification (69–78%) and wastewater (7–15%), and only 14–24% was assimilated into biomass. Similarly, 38–54% of total P input in aquaponics was lost via wastewater (22–28%), precipitations (8–25%), and solid waste (2–7%) and 46–62% was assimilated into biomass (35–45% fish; 11–25% plants). In hydroponics, 79–89% of total P input was lost via wastewater (52–74%) and precipitations (15–27%), and only 11–21% was assimilated into plant biomass. Plant species had a significant impact on N and P distribution, and tomato was most effective in removing N from wastewater and reducing denitrification via higher biomass production compared to basil and lettuce. NUE was lower for aquaponics than for hydroponics when only edible plant parts were taken into consideration, but 71–114% higher when both fish and plant biomass were considered. Meanwhile, PUE was higher for aquaponics than for hydroponics even only when edible parts were considered and 336–369% higher when the biomass of both crops was considered. Our N and P mass balance analyses demonstrated for the first time that aquaponics is more efficient than hydroponics. Greater N and P losses in hydroponics were mainly due to higher N and P inputs, causing 2 times higher N loss via gas emission and up to 3 times higher P loss via inorganic P in wastewater compared to aquaponics. Therefore, reducing nutrient inputs is critical in improving NUE and PUE for both aquaponics and hydroponics, which should be combined with proper crop choice, operation conditions, and management practices to further improve the efficiency of the systems. • N and P mass balances were compared between aquaponics and hydroponics. • Aquaponics decreases N, P loss by 21 and 49% respectively compared to hydroponics. • N-, P-use efficiency (NUE; PUE) was respectively 2, 4 times higher in aquaponics. • Tomato-based aquaponics has higher NUE and PUE than other plant-based systems. • High N and P inputs were the major cause of reduced efficiency in both systems. [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]

The recovery of nutrients from residual fish sludge in aquaponics could achieve zero solid waste discharge and supplement additional nutrients to hydroponics, thus yielding environmental and economic benefits. In this study, novel biological aerated filters (BAFs) with ceramsite plus different lignocellulosic materials (corn straw, wheat straw, and sawdust) are designed and installed in aquaponic systems. The BAFs performed the fish sludge separation and nutrient conversion in a single equipment without the necessity for backwashing. The potential for nutrient recovery from fish sludge is evaluated by comparing four BAFs filled with different media. The BAF with ceramsite plus sawdust achieves the highest mineralization capacity based on nitrification and dissolved total phosphorus. The average concentrations of N, P, K, Ca, Mg, and S macronutrients reach 12.3%, 11.8%, 4.5%, 26.4%, 22.6%, and 46.0% of those of Hoagland nutrient solution, respectively. The recovered Fe, Mn, and B micronutrients are 10.0%, 12.0%, and 18.0%, respectively, whereas Cu, Zn, and Mo are 1.5, 1.8, and 1.0 times, respectively, of those of Hoagland nutrient solution. The estimated nutrient recoveries of Ca, Mg, and S have good performance efficiencies, followed by K and Cu; those of N, P, Fe, Mn, and Zn have potentials for further improvement. The modified aquaponics with BAFs are proposed for the recovery of both dissolved and solid nutrients. Image 10130 • A novel biological aerated filter is designed for nutrient recovery in aquaponics. • Ceramsites mixed with corn straw, wheat straw, and sawdust are tested as filter media. • The highest mineralization capacity is achieved by the use of ceramsite plus sawdust. • The nutrient recovery efficiencies of macronutrients and micronutrients are evaluated. • The modified aquaponics is proposed for the recovery of both dissolved and solid nutrients. [ABSTRACT FROM AUTHOR]

This study presents an environmental life cycle assessment of poultry fat (PF), poultry by-product meal (PBM) and steam hydrolyzed feather meal (HF). These ingredients are obtained by rendering poultry by-products and can be used as valuable feedstuffs for the fish feed industry, displacing traditional fishmeal and fish oil, promoting a circular economy system by reducing waste, adding value to by-products of the poultry production and reintroducing them in the economy as high-value products. A life cycle inventory and model were implemented for the PF, PBM and HF production chains based on data collected from two poultry by-product rendering units: the first producing both PF and PBM, and the second producing only HF. Four environmental impact categories were assessed using the CML life-cycle impact assessment method: global warming (GW), abiotic depletion (AD), acidification (AC) and eutrophication (EUT). The impacts calculated with economic allocation for 1 t of PF, 1 t of PBM and 1 t of HF from poultry by-products are 666, 726 and 597 kg CO 2 eq (GW); 3.8, 4.2 and 3.2 kg Sb eq (AD); 4.2, 4.6 and 4.7 kg SO 2 eq (AC); and 1.8, 2.0 and 2.1 kg PO 4 3− eq (EUT), respectively. The rendering process of by-products is mainly responsible for GW and AD (mainly due to process heat), while the poultry production is the main contributor for AC and EUT. In more detail, a sensitivity analysis of alternative multifunctionality procedures for dealing with poultry by-products was performed, showing that the selected allocation method has a huge influence on the life cycle impacts, with higher impacts when mass allocation is employed instead of economic allocation. Additionally, a sensitivity analysis was conducted on the type of energy used in the rendering process, and distances in poultry by-product transportation to the rendering plants. The results show that the fuel source for process heat or the electricity generation system has a significant influence on the impacts, while the transportation distance has much less. • LCA of valuable feed nutrients (PF, PBM, HF) obtained from rendered by-products. • Circular economy system by reducing waste and adding value to poultry production. • The type of fuel and electricity mix in rendering significantly influence the impacts. • The allocation method applied to poultry by-products highly influences LC impacts. • PF, PBM, HF displacing fishmeal and fish oil can reduce impacts of feed production. [ABSTRACT FROM AUTHOR]

The steady increase in production volume of salmon aquaculture has sharpened concerns about its sustainability. In particular the production of salmon feed is a reason for concern given its reliance on scarce natural resources, such as wild fish captures. Multi-scale integrated analysis is put forward as a tool to anticipate the environmental and socio-economic impacts of large-scale implementation of alternative salmon feeds, considering both plant and insect sources as potential replacements of fish meal and fish oil. The proposed accounting framework, based on relational analysis across hierarchical levels, describes the patterns of required inputs using biophysical and economic variables. It also considers the inputs used by external systems for the production of imported feed, thus providing a coherent assessment of the sustainability of the production system in terms of feasibility, viability, and desirability. The analytical tool-kit is illustrated in conceptual terms and then applied to the Norwegian salmon aquaculture, both in diagnostic (describing the actual situation) and anticipatory mode (examining feed scenarios). Results are used in an exercise of quantitative story-telling to check the quality of the narratives currently shaping policy discussions on aquaculture. Quantitative story-telling is a heuristic approach aimed at checking the robustness of knowledge claims in face of uncertainty. It is concluded that rearing insects in the salmon feed production chain enlarges the option space of feed sources by opening up the possibility of using locally-produced seaweed and organic waste, but also raises the level of uncertainty with regard to the possible insurgence of negative side effects. • The production volume of salmon aquaculture raises concerns about its sustainability. • Potential problems with large-scale use of alternative salmon feeds are analyzed. • A novel approach based on quantitative story-telling and MuSIASEM is applied. • Insect salmon feed allows the use of local resources but raises uncertainty. • The quality of narratives shaping Norwegian salmon aquaculture policy is examined. [ABSTRACT FROM AUTHOR]

• Aquaponics is a good system for sustainable aquaculture but it has serious problems. • Algaquaculture is a novel concept that integrates algae culture with aquaculture. • Algaquaculture is expected to perform better in nutrients recovery and economic value. [ABSTRACT FROM AUTHOR]

Large scale urban agriculture (UA) has been considered as a potential contributor to the sustainability and the resilience of the food system. However, its synergy with the tackling of another main challenge in cities, namely the management of organic wastes, has previously not been extensively explored. The aim of this work is to understand the potential of an integrated food-energy-water-waste system in terms of food production, resource circularity and carbon footprint, in comparison with the current food and waste management systems in cities and an UA system without integration with waste management. Employing spatial analysis and a breadth of process parameters and city-specific data, the monthly material and energy flows were simulated and optimized for two European cities, Glasgow and Lyon. The results indicate a strong dependency of food self-sufficiency, waste assimilation and carbon footprint on the ratio between high-intensity greenhouse growing and urban gardening. For a chosen greenhouse to garden ratio of 1:4, the production of a large share of fruit, vegetable and fish supplied with nutrients from waste products and water from rainwater harvesting is theoretically possible, and the integrated UA systems could assimilate 51.7% and 16.9% of food waste in Glasgow and Lyon, respectively. From a food production perspective, co-located waste valorization could reduce the carbon footprint of the UA system by 7.8% for Glasgow and 12.6% for Lyon. However, overall emissions for the integrated UA system are 75.1% (Glasgow) and 4.3% (Lyon) higher than the current system, primarily due to high heating and lighting requirements for greenhouses in winter, even more so in Glasgow which is colder and with a carbon-intensive electricity grid. However, if a UA system is already in place, the decentralized valorization in combination with UA could provide significant emission reduction benefits compared to existing waste-to-energy schemes, in particular for insect rearing in combination with aquaponics. The outcome may inspire urban policy makers and stakeholders to consider the propagation of urban agriculture in symbiosis with decentralized manage waste strategies, in particular in areas with a low-carbon electricity grid, as a move towards self-sustaining cities and a more circular economy overall. • UA productivity assessment with resource flow analysis of organic waste integration. • Carbon footprint optimization favors waste management via AD and insect rearing. • Emissions influenced by extent of greenhouses and carbon intensity of electricity. • Nutrient, feed and water requirements may be fully met with integrated system. • Organic waste assimilation rather limited even with fully scaled-up UA system. [ABSTRACT FROM AUTHOR]