This thesis intends to introduce the reader to the concept and benefits of aquaponic farming. The paper begins with an introductory definition of aquaponics, a brief history of aquaponic practices, and a status quo of the industry - all meant to contextualize this concept which is, to the general public, widely unknown. Comparisons are then given to competing technologies which are likely more familiar to most. Specifically, the advantages of aquaponic cultivation are weighed against traditional soil farming, hydroponics, and aquaculture. Current limitations facing the industry are discussed before the thesis concludes with an overview of arguments made.

In the summer of 2016 I worked at The Moore Street Market Farm run by Oko Farms LLC., New York City’s first and largest outdoor urban aquaponics company. Aquaponics is a method of farming that combines the cultivation of aquatic animals and plants in a mutually beneficial, symbiotic relationship. While the industry is in its infancy, aquaponics is acknowledged to have great potential to change the future of farming for sustainability, as it uses less water than traditional agriculture and can be implemented almost anywhere. This thesis examines current challenges to the industry and the potential future applications of aquaponics in urban environments, through discussion of current developments in aquaponics in Europe; Growing Power’s use of aquaponics for community benefit in the Milwaukee; as well as in the case-studies of Oko Farms and Agtech aquaponics companies in New York City. While eventually concluding that implementations of aquaponics for profit might not be viable in the long run, this thesis ends with a short discussion on hypothetical successful applications the industry could thrive in.

A salinização dos solos é um dos principais fatores que limita a produtividade mundial. Diversos estudos têm sido realizados para selecionar genótipos mais resistentes. Assim, este trabalho objetivou estudar a fisiologia e a bioquímica das plântulas de bananeira das variedades Maçã e Nanica submetidas ao estresse salino em cultivo hidropônico. 120 plântulas de cada variedade foram fixadas em placas de isopor e colocadas para flutuar sobre 5 litros da solução nutritiva de Hoagland diluída em 10 partes e submetidas aos tratamentos: controle; 25; 50 e 75 mM de NaCl. Mensalmente, durante 60 dias, 60 plântulas de cada variedade tiveram os caracteres fisiológicos altura, número de folhas, comprimento das raízes e taxa de sobrevivência avaliados. Para a avaliação bioquímica, foram calculados os conteúdos de proteínas solúveis totais, aminoácidos livres totais e açúcares solúveis totais nas folhas e nas raízes de 8 plântulas de cada variedade. Os resultados mostraram que o sal induz um efeito prejudicial no crescimento e desenvolvimento das plântulas em todos os caracteres fisiológicos avaliados; que há um incremento no conteúdo dos diversos osmólitos e que a variedade Maçã parece ser mais susceptível aos efeitos prejudiciais do sal. / Soil salinity is one of the main factors that limits world productivity. Different studies have being realized to select more resistant genotypes. Therefore, this work objectified to study the physiology and biochemistry of two banana plantlets varieties Maçã and Nanica submitted to salt stress on the hydroponics culture. 120 plantlets of each variety were fixed in styrofoam plates and placed to fluctuate above 5 liters of Hoagland nutritive solution dilute thin in 10 parts and submitted to the following treatments: control; 25; 50 and 75 mM NaCl. Monthly, during 60 days, 60 plantlets of each variety had the physiological characters height; leaves number; roots length and surviving tax evaluated. For biochemistry evaluation, total soluble protein; total free amino acids and total soluble sugars contents were estimated in leaves and roots of 8 plantlets of each variety. The results showed that the salt has a damage effect on the growing and developing of the plantlets in all of the physiological characters evaluated; there is an increase on osmolytes content and the Maçã variety seems to be more susceptible to the damage effect of the salt.

O manejo da solução nutritiva leva em consideração as concentrações e as relações entre os nutrientes para a obtenção de elevada produtividade e qualidade das hortaliças cultivadas em sistemas hidropônicos. A relação adequada entre K e Ca é fundamental para tornar máxima a absorção desses elementos, uma vez que o excesso de K pode reduzir a absorção de Ca e viceversa. Além dos elementos considerados essenciais, os benéficos como o silício pode estimular a absorção de outros nutrientes, dentre eles o cálcio, aumentar a produtividade e a durabilidade pós-colheita dos produtos. Esse trabalho teve por objetivo avaliar a influência das relações K:Ca 0,75:1,0; 1,25:1,0 e 1,5:1,0 e da aplicação de silício (0 e 56 mg L-1) via solução nutritiva, no crescimento, na produtividade, na marcha de absorção de nutrientes aos 7, 14, 21 e 28 dias após o transplante das mudas (DAT), e na da qualidade pós-colheita do coentro Português Pacífico, cultivado em sistema hidropônico NFT. O experimento foi conduzido em blocos ao acaso, em um fatorial 3x2 (três relações K:Ca: 0,75:1,0; 1,25:1,0 e 1,50:1,0 e dois níveis de Si: 0 e 56 mg L-1), em esquema de parcelas subdivididas no tempo, avaliadas em quatro épocas (7, 14, 21 e 28 dias após transplante das mudas DAT). As relações K:Ca de 1,25:1,0 e 1,50:1,0 originaram plantas mais vigorosas quanto à altura, massa fresca e seca da parte aérea e das raízes, área foliar e número de folhas. O Si aumentou a massa fresca da parte aérea e das raízes e o número de folhas aos 28 DAT. A relação K:Ca 0,75:1,0 na presença de Si proporcionou maior número de estômatos na face abaxial da folha. A maior espessura do parênquima lacunoso foi obtida na K:Ca 1,5:1,0. Na presença de Si, a relação K:Ca 1,5:1,0 foi a que gerou maior espessura do parênquima paliçádico e do mesófilo. A ordem de extração tanto na parte aérea como nas raízes foi: K > N > Ca > P > Mg > S. O acúmulo de N, P, K, Ca, Mg, S e Si pela parte aérea representou 85%, 79,9%, 89,2%, 86,4%, 77,8%, 82,3% e 58,1%, respectivamente, em relação ao total. Nos três dias de armazenamento do coentro ocorreu menor perda de massa nos tratamentos que receberam silício em solução nutritiva. / The management of nutrient solution takes into account nutrient concentrations and relationships between nutrients to achieve high productivity and quality of vegetables grown in hydroponic systems. The appropriate ratio between K and Ca is essential for maximum absorption of these elements, once an excessive amount of K may reduce Ca absorption, and vice versa. Besides the elements considered essential, benefic elements such as silicon may not only stimulate absorption of other nutrients, including Ca, but also increase productivity and longevity of postharvest products. This work aimed to study the influence of relations K: Ca 0,75:1,0; 1,25:1,0 and 1.5:1.0 and application of silicon (0 to 56 mg L-1) nutrient solutions on growth, productivity, nutrient uptake at 7, 14, 21 and 28 days after transplanting (DAT), and postharvest quality coriander Português Pacific, grown in hydroponic system NFT. The experiment was in randomized blocks in factorial scheme 3x2, that is, three ratios K: Ca and two doses of Si, in split plot in time, valued at four times (7, 14, 21 and 28 days after transplanting, DAT) with four replications. The K: Ca 1,50:1,0 and 1,25:1,0 ratio originated more vigorous plants for plant height, fresh and dry weight of shoots and roots, leaf area and leaf number. Si increased in fresh weight of shoots and roots and number of leaves at 28 DAT. The K: Ca 0,75:1,0 ratio in Si the presence of a greater number of stomata under the leaf. The thick spongy parenchyma was obtained with K: Ca 1.5:1.0. In the presence of Si, the ratio K: Ca 1.5:1.0 was the one that created a greater thickness of the palisade and mesophyll. The order of uptake, both in shoots and roots was: K> N> Ca> P> Mg> S. The accumulation of N, P, K, Ca, Mg, S and Si in shooting accounted for 85%, 79.9%, 89.2%, 86.4%, 77.8%, 82.3% and 58.1%, respectively, compared to the total. In three days of coriander storage less weight loss occurred in treatments with silicon in the nutrient solution.

Muitas vezes, a agricultura extensiva falha sob as condições semi-áridas da região Nordeste do Brasil, onde há escassez de águas superficiais e as chuvas são irregulares. O uso de águas subterrâneas poderia melhorar a produtividade das culturas. Mas, devido à condição geológica, é freqüente a ocorrência de águas subterrâneas salobras. A utilização dessas águas levaria à salinização do solo. Além disso, os poços perfurados têm baixas vazões. Nesse cenário, a hidroponia pode ser condizente à produção intensiva, baseada em pequenas áreas. A eficiência do uso da água na hidroponia é reconhecidamente maior que no solo porque torna mínima a perda por evaporação. Além disso, a hidroponia poderia aumentar a tolerância das culturas à salinidade. Isso permitiria o uso de águas salobras e, como benefício extra, incrementaria a proteção ambiental. Em hidroponia, não há o potencial mátrico que leva à diminuição da energia livre da água. Também, a própria estrutura funciona como sistema de drenagem. Os sais acumulados ao final do processo produtivo podem ser facilmente dirigidos para fora do sistema. Com essa hipótese, foram conduzidos experimentos para avaliar a tolerância da alface (cultivar Verônica) à salinidade em hidroponia e em solo. Foi construída uma estrutura experimental (40 parcelas independentes) para simular o cultivo na técnica do fluxo laminar de nutrientes (NFT). Para o cultivo em solo, foram utilizados vasos de 12 L e mulch plástico. Foi observado que na hidroponia NFT é possível empregar águas mais salobras que no cultivo em solo. Quando se têm disponíveis água doce e salobra, pode ser mais interessante usar água doce no preparo da solução nutritiva e água salobra na reposição ao volume consumido. O uso de água salobra para o preparo da solução nutritiva e da água doce para a reposição ao consumo produziu maiores perdas relativas sobre o rendimento do que a salinização gradual. Esse resultado foi proporcionado pela precocidade da alface. Em relação à tolerância, a salinidade limiar da alface 'Verônica' cultivada em hidroponia NFT foi estimada em 4,03 dS m-1. Sob as mesmas condições experimentais, a tolerância em solo foi estimada em 2,51 dS m-1. Esses resultados confirmam a hipótese levantada e permitem apresentar uma alternativa agrícola condizente à realidade de muitas famílias isoladas no semi-árido brasileiro. / Several times, the extensive agriculture fails under semi-arid conditions in the Northeast region of Brazil, where the surface water is shortage and the pluvial precipitation is irregular. The use of groundwaters could increase the crops yield. However, due to the geological factors, it is usual the occurrence of brackish groundwaters in this region. The utilization of these waters would carry to soil salinization. Moreover, the opened deep tubewells often have low capacity. In this scenario, the hydroponics systems may be suitable to intensive production based in reduced areas. The higher water use efficiency in soilless cultivation is a well reported advantage, because in this system the water loss by evaporation is minimum. In hydroponics systems could be increase the crop salt tolerance. This would permit the brackish water use and, as an extra benefit, would increase the environmental safety. In hydroponics system, there is no the matric potential, which decreases the free-energy of water. Furthermore, the hydroponics structure operates as a drainage system. The accumulated salts, at the end of the period, may be easily removed from system. In order to test this hypothesis, were carried out experiments to evaluate the lettuce (cv. Verônica) salt tolerance under soil and hydroponics conditions. It was constructed a structure (40 independent experimental units) to simulate the Nutrient Technique Film (NFT) cultivation. For the soil experiment, it was used 12 L recipients and plastic mulch. It was registered that is feasible use waters more brackish in NFT system than in soil. For available of brackish and nonsaline waters, it was more productive to use non-saline water to prepare the nutrient solution and brackish water to supply the water consumption. Higher yield losses were observed with the use the brackish water to prepare nutrient solution and the non-saline water to replace the water consumption. The nutrient solution salinization was less depreciative to yield than the constant salinity. This finding was providing by the lettuce precocity. In relation to the salt tolerance in NFT system, the lettuce salinity threshold was estimated in 4.03 dS m-1. Under the same experimental conditions, the tolerance in soil was estimated in 2.51 dS m-1. These results confirmed the hypothesis and permit to present an agricultural alternative suitable to reality of many isolated families in Brazilian semi-arid.

O manejo da solução nutritiva leva em consideração as concentrações e as relações entre os nutrientes para a obtenção de elevada produtividade e qualidade das hortaliças cultivadas em sistemas hidropônicos. A relação adequada entre K e Ca é fundamental para tornar máxima a absorção desses elementos, uma vez que o excesso de K pode reduzir a absorção de Ca e viceversa. Além dos elementos considerados essenciais, os benéficos como o silício pode estimular a absorção de outros nutrientes, dentre eles o cálcio, aumentar a produtividade e a durabilidade pós-colheita dos produtos. Esse trabalho teve por objetivo avaliar a influência das relações K:Ca 0,75:1,0; 1,25:1,0 e 1,5:1,0 e da aplicação de silício (0 e 56 mg L-1) via solução nutritiva, no crescimento, na produtividade, na marcha de absorção de nutrientes aos 7, 14, 21 e 28 dias após o transplante das mudas (DAT), e na da qualidade pós-colheita do coentro Português Pacífico, cultivado em sistema hidropônico NFT. O experimento foi conduzido em blocos ao acaso, em um fatorial 3x2 (três relações K:Ca: 0,75:1,0; 1,25:1,0 e 1,50:1,0 e dois níveis de Si: 0 e 56 mg L-1), em esquema de parcelas subdivididas no tempo, avaliadas em quatro épocas (7, 14, 21 e 28 dias após transplante das mudas DAT). As relações K:Ca de 1,25:1,0 e 1,50:1,0 originaram plantas mais vigorosas quanto à altura, massa fresca e seca da parte aérea e das raízes, área foliar e número de folhas. O Si aumentou a massa fresca da parte aérea e das raízes e o número de folhas aos 28 DAT. A relação K:Ca 0,75:1,0 na presença de Si proporcionou maior número de estômatos na face abaxial da folha. A maior espessura do parênquima lacunoso foi obtida na K:Ca 1,5:1,0. Na presença de Si, a relação K:Ca 1,5:1,0 foi a que gerou maior espessura do parênquima paliçádico e do mesófilo. A ordem de extração tanto na parte aérea como nas raízes foi: K > N > Ca > P > Mg > S. O acúmulo de N, P, K, Ca, Mg, S e Si pela parte aérea representou 85%, 79,9%, 89,2%, 86,4%, 77,8%, 82,3% e 58,1%, respectivamente, em relação ao total. Nos três dias de armazenamento do coentro ocorreu menor perda de massa nos tratamentos que receberam silício em solução nutritiva. / The management of nutrient solution takes into account nutrient concentrations and relationships between nutrients to achieve high productivity and quality of vegetables grown in hydroponic systems. The appropriate ratio between K and Ca is essential for maximum absorption of these elements, once an excessive amount of K may reduce Ca absorption, and vice versa. Besides the elements considered essential, benefic elements such as silicon may not only stimulate absorption of other nutrients, including Ca, but also increase productivity and longevity of postharvest products. This work aimed to study the influence of relations K: Ca 0,75:1,0; 1,25:1,0 and 1.5:1.0 and application of silicon (0 to 56 mg L-1) nutrient solutions on growth, productivity, nutrient uptake at 7, 14, 21 and 28 days after transplanting (DAT), and postharvest quality coriander Português Pacific, grown in hydroponic system NFT. The experiment was in randomized blocks in factorial scheme 3x2, that is, three ratios K: Ca and two doses of Si, in split plot in time, valued at four times (7, 14, 21 and 28 days after transplanting, DAT) with four replications. The K: Ca 1,50:1,0 and 1,25:1,0 ratio originated more vigorous plants for plant height, fresh and dry weight of shoots and roots, leaf area and leaf number. Si increased in fresh weight of shoots and roots and number of leaves at 28 DAT. The K: Ca 0,75:1,0 ratio in Si the presence of a greater number of stomata under the leaf. The thick spongy parenchyma was obtained with K: Ca 1.5:1.0. In the presence of Si, the ratio K: Ca 1.5:1.0 was the one that created a greater thickness of the palisade and mesophyll. The order of uptake, both in shoots and roots was: K> N> Ca> P> Mg> S. The accumulation of N, P, K, Ca, Mg, S and Si in shooting accounted for 85%, 79.9%, 89.2%, 86.4%, 77.8%, 82.3% and 58.1%, respectively, compared to the total. In three days of coriander storage less weight loss occurred in treatments with silicon in the nutrient solution.

Muitas vezes, a agricultura extensiva falha sob as condições semi-áridas da região Nordeste do Brasil, onde há escassez de águas superficiais e as chuvas são irregulares. O uso de águas subterrâneas poderia melhorar a produtividade das culturas. Mas, devido à condição geológica, é freqüente a ocorrência de águas subterrâneas salobras. A utilização dessas águas levaria à salinização do solo. Além disso, os poços perfurados têm baixas vazões. Nesse cenário, a hidroponia pode ser condizente à produção intensiva, baseada em pequenas áreas. A eficiência do uso da água na hidroponia é reconhecidamente maior que no solo porque torna mínima a perda por evaporação. Além disso, a hidroponia poderia aumentar a tolerância das culturas à salinidade. Isso permitiria o uso de águas salobras e, como benefício extra, incrementaria a proteção ambiental. Em hidroponia, não há o potencial mátrico que leva à diminuição da energia livre da água. Também, a própria estrutura funciona como sistema de drenagem. Os sais acumulados ao final do processo produtivo podem ser facilmente dirigidos para fora do sistema. Com essa hipótese, foram conduzidos experimentos para avaliar a tolerância da alface (cultivar Verônica) à salinidade em hidroponia e em solo. Foi construída uma estrutura experimental (40 parcelas independentes) para simular o cultivo na técnica do fluxo laminar de nutrientes (NFT). Para o cultivo em solo, foram utilizados vasos de 12 L e mulch plástico. Foi observado que na hidroponia NFT é possível empregar águas mais salobras que no cultivo em solo. Quando se têm disponíveis água doce e salobra, pode ser mais interessante usar água doce no preparo da solução nutritiva e água salobra na reposição ao volume consumido. O uso de água salobra para o preparo da solução nutritiva e da água doce para a reposição ao consumo produziu maiores perdas relativas sobre o rendimento do que a salinização gradual. Esse resultado foi proporcionado pela precocidade da alface. Em relação à tolerância, a salinidade limiar da alface 'Verônica' cultivada em hidroponia NFT foi estimada em 4,03 dS m-1. Sob as mesmas condições experimentais, a tolerância em solo foi estimada em 2,51 dS m-1. Esses resultados confirmam a hipótese levantada e permitem apresentar uma alternativa agrícola condizente à realidade de muitas famílias isoladas no semi-árido brasileiro. / Several times, the extensive agriculture fails under semi-arid conditions in the Northeast region of Brazil, where the surface water is shortage and the pluvial precipitation is irregular. The use of groundwaters could increase the crops yield. However, due to the geological factors, it is usual the occurrence of brackish groundwaters in this region. The utilization of these waters would carry to soil salinization. Moreover, the opened deep tubewells often have low capacity. In this scenario, the hydroponics systems may be suitable to intensive production based in reduced areas. The higher water use efficiency in soilless cultivation is a well reported advantage, because in this system the water loss by evaporation is minimum. In hydroponics systems could be increase the crop salt tolerance. This would permit the brackish water use and, as an extra benefit, would increase the environmental safety. In hydroponics system, there is no the matric potential, which decreases the free-energy of water. Furthermore, the hydroponics structure operates as a drainage system. The accumulated salts, at the end of the period, may be easily removed from system. In order to test this hypothesis, were carried out experiments to evaluate the lettuce (cv. Verônica) salt tolerance under soil and hydroponics conditions. It was constructed a structure (40 independent experimental units) to simulate the Nutrient Technique Film (NFT) cultivation. For the soil experiment, it was used 12 L recipients and plastic mulch. It was registered that is feasible use waters more brackish in NFT system than in soil. For available of brackish and nonsaline waters, it was more productive to use non-saline water to prepare the nutrient solution and brackish water to supply the water consumption. Higher yield losses were observed with the use the brackish water to prepare nutrient solution and the non-saline water to replace the water consumption. The nutrient solution salinization was less depreciative to yield than the constant salinity. This finding was providing by the lettuce precocity. In relation to the salt tolerance in NFT system, the lettuce salinity threshold was estimated in 4.03 dS m-1. Under the same experimental conditions, the tolerance in soil was estimated in 2.51 dS m-1. These results confirmed the hypothesis and permit to present an agricultural alternative suitable to reality of many isolated families in Brazilian semi-arid.

Resumo: O objetivo do trabalho foi avaliar o desenvolvimento, as trocas gasosas, o rendimento e a composição do óleo essencial de Mentha piperita L. cultivada em solução nutritiva no2 Hoagland & Arnon (1950) com variação dos níveis de N, P, K e Mg. Assim, os tratamentos com 50% de N, P, K e 25% de Mg continha 94,0/15,5/107,5/12,15, com 50% de N, P, K e Mg continha 94,0/15,5/107,5/24,3, com 65% de N, 50% de P, 25% de K e 100% de Mg, continha 124,0/15,5/53,6/48,6 e com solução completa continha 189,0/31,0/214,5/48,6 mg L-1 de N/P/K/Mg. As variáveis avaliadas foram comprimento de parte aérea, massas secas dos diferentes órgãos, área foliar, razão de área foliar (RAF), área foliar específica (AFE), taxa assimilatória líquida (TAL), taxa de crescimento relativo (TCR), razão de massa foliar (RMF), distribuição de massa seca para os diferentes órgãos, assimilação de CO2 (A), transpiração (E), concentração intercelular de CO2 (Ci), condutância estomática (gs), resistência estomática (S%), ponto de compensação (PtCe), eficiência de carboxilação da rubisco, rendimento e composição do óleo essencial e teores de macro e micronutrientes em lâminas foliares e caules e pecíolos. Os resultados obtidos foram avaliados estatisticamente por análise de variância do fatorial e análise de regressão polinomial, utilizando-se o programa computacional SAS, com o nível de 5% de significância. As variáveis, comprimento, área foliar, massa seca dos diversos órgãos e total apresentaram variância heterogênea entre tratamentos, o que levou a utilização de análise de regressão ponderada e transformação logarítmica dos resultados para a análise de variância. Os resultados dos 18 índices fisiológicos, foram estimados pelo programa ANACRES. As plantas cultivadas com a solução nutritiva completa apresentaram maior TAL até 35 dias após transplante ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: :The aim of this stundy was to evaluate the development, gas exchange, yield and composition of essential oil of Mentha piperita L. cultivated in no 2 Hoagland & Arnon nutritive solution with varying levels of nitrogen, phosphorus, potassion and magnesium. Treatment of 50% nitrogen, phosphorus, potassion and 25% of magnesium content 94,0/15,5/107,5/12,15, Treatment of 50% nitrogen, phosphorus, potassion and magnesium content 94,0/15,5/107,5/24,3, Treatment of 65% de nitrogen, 50% phosphorus, 25% potassion and 100% magnesium, content 124,0/15,5/53,6/48,6 and Treatment of 100% nitrogen, phosphorus, potassion and magnesium content 189,0/31,0/214,5/48,6 mg L-1. The parameters evaluate were Shoot length, leaf area, and dry matter of leaf blades, stems plus petioles, roots and total,relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR) and specific leaf area (SLA), leaf mass ratio (LMR), dry matter distribution in several organs (DMD), CO2 assimilation (A), transpiration (E), Intracelular CO2 concentration, stomatal conductance (gs), stomatal resistence (S%), CO2 compensation point (PtCe), Rubisco carboxlation efficiency, yield and composition oil. The results were evaluated by factorial ANOVA and polynomial regression analisys, usen SAS softwear with 5% significance. The parameters, Shoot length, leaf area, and dry matter of leaf blades, stems plus petioles, roots and total showed heterocedastcity making necessary the use of ponderated regression analisys and logarithmic transformation. The physiological indexes were stimated using ANACRES softwear. Plants grown whit complete nutritive solution presented higher TAL until 35 days after transplantation (DAT) and deacreased AFE at the begining of the cicle. TCR evolution was similar in different levels. Plants grown 50% N, P, K and Mg showed higher RAF and lower TAL, what ...(Complete abstract click electronic access below) / Orientador: Carmen Silvia Fernandes Boaro / Coorientador: Gustavo Habermann / Banca: João Domi ngos Rodrigues / Banca: Marcia Ortiz Mayo Marques / Banca: Vandeir Francisco Guimarães / Banca: José Abramo Marchese / Doutor

The imbalance between global population growth and resource consumption is indicative of unsustainable practices and foreshadows a grim future of continued resource depletion, food and water scarcity, social inequality, and deteriorating public and environmental health. Meanwhile, the urban centers of the world continue to experience exponential growth resulting in overwhelmed food, water, and sanitation infrastructure. Decentralized and satellite wastewater treatment technologies capable of resource recovery, such as anaerobic membrane bioreactors (AnMBR), foster synergistic opportunities to help manage the food, energy, and water sectors of urban environments. Specifically, the nutrient concentration and high effluent quality of permeate produced by AnMBR systems present applicability in controlled environment agriculture (CEA). The efficacy of AnMBR permeate is evaluated in a hydroponics growth study of cucumber (Cucumis sativus) grown in an outdoor greenhouse and tomato (Lycopersicon lycopersicum) grown indoors. Nutrient analysis of permeate generated by a small, pilot scale AnMBR developed for the treatment of domestic wastewater at ambient temperature indicated sufficient concentrations of N and P elements, however high proportion of NH4+ in N species decreased growth performance. Opportunities for optimizing AnMBR permeate for hydroponics applications exist and thus imply synergistic integration of decentralized AnMBR technology with controlled environment agriculture (CEA) such as hydroponics. A model is proposed for the integration of decentralized AnMBR and CEA systems capable of producing usable plant products within the urban environment. The integration of these systems is proposed as a solution to the challenges of with food security, stressed water supplies, and environmental degradation associated with unchecked urban growth in the developing and developed world

As part of a research project aiming to develop and evaluate a hydroponic system for wastewater treatment in Sweden, extended nutrient removal by microalgae was tested. The hydroponic/microalgal wastewater treatment system was built in a greenhouse in order to improve growth conditions for plants and algae. Studies on the treatment step with microalgae showed that phosphorus removal could be successfully accomplished owing to the cmbined effect of phosphorus assimilation and biologically mediated chemical precipitation of calcium phosphates. This precipitation was mainly induced by the increased pH in the algal cultures, and the pH increase was in turn a result of the inorganic carbon assimilation by the algae. The results showed that the algal growth was mainly light limited which resulted in higher algal biomass density and also lowe residual nutrients in the water at longer hydraulic retention times (HRT). In contrast the phosphorus removal rate was load limited, i.e. shorter HRT gave higher removal rates. This load dependency was due to the chemical precipitation, whereas the phosphorus assimilation was dependent on algal growth. Furthermore, results from an intensive study during summer showed that culture depths of 17 cm gave higher removal efficiencies (78% - 92%) than cultures of 33 cm (66% - 88%). On the other hand, the removal rate per area was higher in the deeper cultures, which implies that these may be preferred if area is of concern. Nitrogen removal was achieved mainly by the assimilation of nitrate to algal biomass, and removal efficiencies of around 40% (nitrate) could be reached for most parts of the year although the nitrogen removal performance was quite uneven. Up to 60% - 80% could however be reached during summer in the shallow cultures. A net removal in total nitrogen of up to 40% was observed in the shallow cultures during summer, which was most probably a consequence of grazing zooplankton and subsequent urea excretion and ammonia volatilisation as a reslt of the high pH values. Over the year, there were large fluctuations in algal growth and removal efficiency as a result of the seasonal variations in light and tempeature. During winter, phosphorus removal efficiencies lower than 25% were observed in the shallow tanks and lower than 10% in the deep tanks. Additional illumination during winter improved the phosphorus removal in the shallow cultures but did not have a significant efect on the deep cultures. Such additional illumination increases the total energy demand of the system, and hence alternative methods for phosphorus removal during winter would probably be more economical unless the algal biomass roduced had great commercial value. / QC 20100907