<p>Sustainable food production is about producing more and better with less.As an emerging CEA system, aquaponics integrates recirculating aquaculture systems and hydroponics and can achieve the three SDGs mentioned above. However, challenges in sustainable aquaponics commercialization remains and my thesis addresses the following three layers of sustainable aquaponics  development:  sustainability  assessment,  sustainable  system  design  and management, understanding biological mechanisms for scalability.</p> <p>I conducted acradle-to-gate life cycle assessment (LCA)and compared the environmental performance, on an economic basis, of aquaponics andhydroponics withidentical system design in Indiana, US. Aquaponics produced 45% lower endpoint environmental impact than hydroponics.Electricity use for greenhouse heating and lighting, and water pumping and heating contributed to themajority of the environmental impacts of both systems, which was followed by the production of fishfeed and fertilizers. However, changing the energy source from coal to wind power could make thehydroponic system more environment-friendly than the aquaponic system. This LCA study can provideCEA farmers with the groundwork to reduce the environmental cost of their production.</p> <p>Aquaponics uses bacterial processes and plant nutrient uptake to recover nutrient from aquaculture wastewater. However, little is known which wastewater management strategy, autotrophic or heterotrophic, is best suited for the four objectives: nutrient recovery, system reliability, and growth and physiological welfare of fish and plants. In this study, I found that pH6 had the highest nitrogen (N) use efficiency (NUE) (assimilated by fish and plants, 65.5%) and the lowest N loss as gas (34.5%), followed by pH6M (55.5% and 44.5%,respectively), suggesting that lower pH and less organic carbon in aquaponics could enhance NUE and reduce N loss. pH6M had the highest phosphorus (P) use efficiency (PUE) (assimilated by fish and plants, 65.0%) suggesting that lower pH and organic carbonaddition could facilitate P recovery from wastewater. </p> <p>Reverse osmosis (RO) water enables aquaculture to expand in places where natural water is not desirable and reduces uncertainty in the operation. However, high K+environment of RO in  aquaponics  couldinduce  physiological  stress,  but  adaptation  mechanism  is  unknown. Proteomic analysis revealed up-regulation of stress response proteins and down-regulation of V-type H+-ATPase and other ion transporters, suggesting cellular adaptation of fish to RO water stress. In conclusion, fish was able to accommodate to the RO environment and the benefits of efficient ammonia excretion and increased feed consumption outweighed the stress caused by RO. RO water could be a standardized water source for better animal welfare, reduce uncertainty in production and assist scaling up aquaponics industry.</p>

O uso de efluente de estação de tratamento de esgoto (EETE) na agricultura irrigada pode ser uma estratégia alternativa de fornecimento de água e nutrientes para culturas agrícolas. Entretanto se realizado por longos períodos pode adicionar grandes quantidades de sódio ao solo o que poderia levar a degradação de suas propriedades e impacto em aspectos agronômicos de capim Tifton 85. Esse trabalho consistiu de dois objetivos: i) avaliar os efeitos da irrigação com efluente rico em sódio durante mais de oito anos em propriedades químicas e físico-hídricas de um Argissolo Vermelho. Para isso foram estabelecidos três tratamentos avaliados nas profundidades de 0,05-0,15 (P1), 0,25-0,35 (P2) e 0,70-0,80 m (P3): SI - cultivo de capim sem adubação e sem irrigação; A100 - cultivo irrigado com água de abastecimento sódica e adubado com 520,0 kg ha-1 ano-1 de nitrogênio; E66 - cultivo irrigado com EETE e adubado com 343,2 kg ha-1 ano-1 de nitrogênio. Foram determinados: pH do solo (em água e CaCl2), condutividade elétrica do extrato aquoso do solo (CE1:1), concentração de sódio (Na+), potássio (K+), cálcio (Ca2+), magnésio (Mg2+), alumínio (Al3+), carbono (C) e nitrogênio (N) do solo, com posterior cálculo de soma de bases (SB), capacidade de troca catiônica (CTC), saturação por bases (V) e percentagem de sódio trocável (PST); densidade do solo (?), argila dispersa em água (ADA), condutividade hidráulica do solo saturado (Ksat), curva de retenção da água no solo (CR), porosidade do solo (?) e distribuição do tamanho dos poros; ii) avaliar os efeitos da irrigação com efluente rico em sódio durante mais de oito anos em aspectos agronômicos de capim Tifton 85. Para alcançar o segundo objetivo foi estabelecido além do SI, A100 e E66, mais quatro tratamentos: A0 - cultivo de capim sem adubação e irrigado com água de abastecimento sódica; E0, E33 e E100 - cultivo de capim irrigado com EETE e adubado com 0, 171,6 e 520,0 kg ha-1 ano-1 de nitrogênio, respectivamente. Foram determinados: produtividade de massa seca estacional (MS-Estacional), anual (MS-Anual) e acumulação estacional e anual de nitrogênio (N-MS), potássio (K-MS) e sódio (Na-MS) no tecido vegetal de capim Tifton 85. Houve alterações nas propriedades químicas e físico-hídricas do solo em função dos tratamentos e profundidades. Na P1 o E66 aumentou a CE1:1, a densidade do solo, o conteúdo de água residual e diminuiu a concentração de Mg2+ e conteúdo de água de saturação. Já o A100 reduziu a concentração de K+ e Mg2+, o conteúdo de água de saturação e aumentou a densidade do solo e o conteúdo de água residual. Na P2 o E66 aumentou o pH-H2O e a CE1:1, o conteúdo de água de saturação e o conteúdo residual. O A100 aumentou o pH-H2O, o Na+, o PST, a argila dispersa em água, o conteúdo de água de saturação e o conteúdo residual e diminuiu o C e N. Na P3 o E66 aumentou apenas o pH-H2O e o conteúdo de água residual e reduziu o conteúdo de água de saturação. O A100 aumentou o conteúdo de água de saturação, o conteúdo de água residual e a mesoporosidade. As propriedades do solo da P2 parecem ser as mais afetadas pelos efeitos do sódio decorrentes, principalmente, do uso de irrigação com água sódica. As produtividades de MS e acumulação de N-MS e K-MS foram superiores nos tratamentos E66, E100 e A100 e não foram reduzidas ao longo destes anos. A acumulação de Na-MS foi proporcional à produtividade, mas o capim passou a acumular um pouco menos sódio. Na estação chuvosa a MS de capim representou cerca de 72% da MS-Anual, sendo influenciada fortemente pelo período de estacionalidade. / The use of treated sewage effluent (TSE) in irrigated agriculture can be an alternative strategy to supply water and nutrients to crops. However if applied for long periods of time, it can add large amounts of sodium to the soil, resulting in soil properties degradation and impacts on agronomic aspects Tifton 85 Bermudagrass. The objectives of this work were: i) evaluate the effect of irrigation with sodium rich effluent for more than eight years on chemical, physical and hydraulic properties of an Ultisol. For this were established three treatments (WI - growing grass without fertilization or irrigation ; FW100 - irrigation with sodic fresh water supply and fertilized with 520.0 kg ha-1 year-1 nitrogen; E66 - irrigation with TSE and fertilized with 343.2 kg ha-1 year-1 nitrogen) The effects were evaluated at different depths (D1: 0.5-0.15, D2: 0.25-0.35 and D3: 0.70-0.80 m), determining: soil pH (in water and CaCl2), soil electrical conductivity of the aqueous extract (EC1:1) sodium concentration (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), aluminum (Al3+), soil carbon (C) and soil nitrogen (N), with subsequent calculation of sum of bases (SB), cation exchange capacity (CEC), base saturation (V) and exchangeable sodium percentage (ESP); bulk density (?), water dispersible clay (WDC), saturated hydraulic conductivity (Ksat), soil water retention curve (SWRC), soil porosity (?) and pore size distribution. Another objective was to evaluate the effect of irrigation with sodium rich effluent for more than eight years on agronomic aspects of Tifton 85 Bermudagrass. In addition to WI, FW100 and E66 treatments were established another four treatments (FW0 - growing grass without fertilizer and irrigated with sodic water supply; E0, E33 and E100 - growing grass irrigated with TSE and fertilized with 0, 171.6 and 520.0 kg ha-1 year-1 nitrogen, respectively) and determined the productivity of seasonal dry matter (Seasonal-DM), annual (Annual-DM) and nitrogen (N-DM), potassium (K-DM) and sodium (Na-DM) seasonal accumulation and annual in the plant tissue of Tifton 85 Bermudagrass. There were changes in chemical, physical and hydraulic soil properties as a function of treatments and depths. In the D1 the E66 treatment increased CE1:1, the bulk density, the residual water content and decreased the concentration of Mg2+, water content at saturation. FW100 reduced the concentration of K+ and Mg2+, the water content at saturation and increased soil bulk density and residual water content. In the D2, the E66 treatment increased pH-H2O and CE1:1, the water content at saturation and residual water content. The FW100 increased pH-H2O, Na+, ESP, water dispersible clay , the content of water saturation and residual contents and decreased C and N. In the D3 the E66 only increased the pH-H2O and residual water content and reduced water content saturation. The FW100 increased the water content at saturation point, residual water content and mesoporosity. The soil properties of D2 aparently are more affected than other depths by the effects of sodium, mainly from the use of irrigation water with sodium. The DM, N-DM and, K-DM were higher in the treatments E66, E100 and FW100 and there were not observed reductions over the years. The accumulation Na-DM was proportional to productivity, but the grass began to accumulate less sodium. In the rainy season the grass DM accounted for approximately 72% of Annual-DM, being strongly influenced by seasonality period.

O uso de efluente de estação de tratamento de esgoto (EETE) na agricultura irrigada pode ser uma estratégia alternativa de fornecimento de água e nutrientes para culturas agrícolas. Entretanto se realizado por longos períodos pode adicionar grandes quantidades de sódio ao solo o que poderia levar a degradação de suas propriedades e impacto em aspectos agronômicos de capim Tifton 85. Esse trabalho consistiu de dois objetivos: i) avaliar os efeitos da irrigação com efluente rico em sódio durante mais de oito anos em propriedades químicas e físico-hídricas de um Argissolo Vermelho. Para isso foram estabelecidos três tratamentos avaliados nas profundidades de 0,05-0,15 (P1), 0,25-0,35 (P2) e 0,70-0,80 m (P3): SI - cultivo de capim sem adubação e sem irrigação; A100 - cultivo irrigado com água de abastecimento sódica e adubado com 520,0 kg ha-1 ano-1 de nitrogênio; E66 - cultivo irrigado com EETE e adubado com 343,2 kg ha-1 ano-1 de nitrogênio. Foram determinados: pH do solo (em água e CaCl2), condutividade elétrica do extrato aquoso do solo (CE1:1), concentração de sódio (Na+), potássio (K+), cálcio (Ca2+), magnésio (Mg2+), alumínio (Al3+), carbono (C) e nitrogênio (N) do solo, com posterior cálculo de soma de bases (SB), capacidade de troca catiônica (CTC), saturação por bases (V) e percentagem de sódio trocável (PST); densidade do solo (?), argila dispersa em água (ADA), condutividade hidráulica do solo saturado (Ksat), curva de retenção da água no solo (CR), porosidade do solo (?) e distribuição do tamanho dos poros; ii) avaliar os efeitos da irrigação com efluente rico em sódio durante mais de oito anos em aspectos agronômicos de capim Tifton 85. Para alcançar o segundo objetivo foi estabelecido além do SI, A100 e E66, mais quatro tratamentos: A0 - cultivo de capim sem adubação e irrigado com água de abastecimento sódica; E0, E33 e E100 - cultivo de capim irrigado com EETE e adubado com 0, 171,6 e 520,0 kg ha-1 ano-1 de nitrogênio, respectivamente. Foram determinados: produtividade de massa seca estacional (MS-Estacional), anual (MS-Anual) e acumulação estacional e anual de nitrogênio (N-MS), potássio (K-MS) e sódio (Na-MS) no tecido vegetal de capim Tifton 85. Houve alterações nas propriedades químicas e físico-hídricas do solo em função dos tratamentos e profundidades. Na P1 o E66 aumentou a CE1:1, a densidade do solo, o conteúdo de água residual e diminuiu a concentração de Mg2+ e conteúdo de água de saturação. Já o A100 reduziu a concentração de K+ e Mg2+, o conteúdo de água de saturação e aumentou a densidade do solo e o conteúdo de água residual. Na P2 o E66 aumentou o pH-H2O e a CE1:1, o conteúdo de água de saturação e o conteúdo residual. O A100 aumentou o pH-H2O, o Na+, o PST, a argila dispersa em água, o conteúdo de água de saturação e o conteúdo residual e diminuiu o C e N. Na P3 o E66 aumentou apenas o pH-H2O e o conteúdo de água residual e reduziu o conteúdo de água de saturação. O A100 aumentou o conteúdo de água de saturação, o conteúdo de água residual e a mesoporosidade. As propriedades do solo da P2 parecem ser as mais afetadas pelos efeitos do sódio decorrentes, principalmente, do uso de irrigação com água sódica. As produtividades de MS e acumulação de N-MS e K-MS foram superiores nos tratamentos E66, E100 e A100 e não foram reduzidas ao longo destes anos. A acumulação de Na-MS foi proporcional à produtividade, mas o capim passou a acumular um pouco menos sódio. Na estação chuvosa a MS de capim representou cerca de 72% da MS-Anual, sendo influenciada fortemente pelo período de estacionalidade. / The use of treated sewage effluent (TSE) in irrigated agriculture can be an alternative strategy to supply water and nutrients to crops. However if applied for long periods of time, it can add large amounts of sodium to the soil, resulting in soil properties degradation and impacts on agronomic aspects Tifton 85 Bermudagrass. The objectives of this work were: i) evaluate the effect of irrigation with sodium rich effluent for more than eight years on chemical, physical and hydraulic properties of an Ultisol. For this were established three treatments (WI - growing grass without fertilization or irrigation ; FW100 - irrigation with sodic fresh water supply and fertilized with 520.0 kg ha-1 year-1 nitrogen; E66 - irrigation with TSE and fertilized with 343.2 kg ha-1 year-1 nitrogen) The effects were evaluated at different depths (D1: 0.5-0.15, D2: 0.25-0.35 and D3: 0.70-0.80 m), determining: soil pH (in water and CaCl2), soil electrical conductivity of the aqueous extract (EC1:1) sodium concentration (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), aluminum (Al3+), soil carbon (C) and soil nitrogen (N), with subsequent calculation of sum of bases (SB), cation exchange capacity (CEC), base saturation (V) and exchangeable sodium percentage (ESP); bulk density (?), water dispersible clay (WDC), saturated hydraulic conductivity (Ksat), soil water retention curve (SWRC), soil porosity (?) and pore size distribution. Another objective was to evaluate the effect of irrigation with sodium rich effluent for more than eight years on agronomic aspects of Tifton 85 Bermudagrass. In addition to WI, FW100 and E66 treatments were established another four treatments (FW0 - growing grass without fertilizer and irrigated with sodic water supply; E0, E33 and E100 - growing grass irrigated with TSE and fertilized with 0, 171.6 and 520.0 kg ha-1 year-1 nitrogen, respectively) and determined the productivity of seasonal dry matter (Seasonal-DM), annual (Annual-DM) and nitrogen (N-DM), potassium (K-DM) and sodium (Na-DM) seasonal accumulation and annual in the plant tissue of Tifton 85 Bermudagrass. There were changes in chemical, physical and hydraulic soil properties as a function of treatments and depths. In the D1 the E66 treatment increased CE1:1, the bulk density, the residual water content and decreased the concentration of Mg2+, water content at saturation. FW100 reduced the concentration of K+ and Mg2+, the water content at saturation and increased soil bulk density and residual water content. In the D2, the E66 treatment increased pH-H2O and CE1:1, the water content at saturation and residual water content. The FW100 increased pH-H2O, Na+, ESP, water dispersible clay , the content of water saturation and residual contents and decreased C and N. In the D3 the E66 only increased the pH-H2O and residual water content and reduced water content saturation. The FW100 increased the water content at saturation point, residual water content and mesoporosity. The soil properties of D2 aparently are more affected than other depths by the effects of sodium, mainly from the use of irrigation water with sodium. The DM, N-DM and, K-DM were higher in the treatments E66, E100 and FW100 and there were not observed reductions over the years. The accumulation Na-DM was proportional to productivity, but the grass began to accumulate less sodium. In the rainy season the grass DM accounted for approximately 72% of Annual-DM, being strongly influenced by seasonality period.

Enhanced biological phosphorus removal (EBPR) was researched from the performance of a modified University of Cape Town (UCT), anaerobic-anoxic/nitrifying-aerobic process. The work focussed on high P influent where milk was compared to carbohydrates as exogenous added carbon and typical settled sewage. The results confirmed that at equal COD load in the influent (minimum COD:P (250:5) ratio for EBPR), milk always provided sufficient soluble substrate than the carbohydrate mix, but also improved the EBPR performance. The laboratory scale treated 10L/day where 2 parallel treatment trains for milk and an equivalent carbohydrate mix as supplement to compare and study the P sequestration from hypothesised P ligands in milk and easily assimilable carbon (AOM) after fermentation for biological P uptake. The aerobic bioreactors used submerged flat sheet membranes (AeMBR) to improve the effluent quality and reduce the suspended solid residues. The results suggested extra benefits from adding calcium chloride (CaCl2) (200 ml at 250 mM/day or 200 mg/L treated) to form P complexes both in the anaerobic and aerobic zones (100 ml CaCl2 250mM/zone/day). To complete P removal a calcium phosphate (CaPO4) further treatment stage (post membrane final effluent (F.E.)) was added for nucleation. The combination of, A2O-N, exogenous carbon and calcium addition improved the performance of the EBPR, and enabled the laboratory units to achieve less than the 1 mg/L P required by the EU Directive. The process was tested at higher than normal P loads (maximum 100 mg/L) (domestic wastewater influent 15 mg/L). Experiments with influent P load ≤ 50mg/L, with 1% milk as AOM were compared to the carbohydrate mix and could remove soluble P to less than 1mg/L above 97% and less than 2 mg/L more than 99% of the in the time respectively. With an influent P load of 60mg/L (maximum 100 mg/L), the soluble P in the F.E. with milk was below 5 mg/L and below 8 mg/L with carbohydrates mix. The results showed that most of the phosphorus was retained by the sludge during the anoxic-aerobic phases. The remaining phosphate in the F.E. was able to pass through AeMBR pore size (0.4 μm) and needed to be chelated by the nucleation process. The results indicated this A2O-N modifications achieved stable nutrient removal and also offered the potential for more sustainable phosphorus recovery. The EBPR without AOM was 25% less efficient compared to milk and never achieved the E.U standard of 1mg/L in final effluent. The flat sheet membrane always achieved a NTU final effluent below 1 and the TOC always greater than 90% removal or less than the EU 125 standard regardless of the feeding COD/P ratio.