Riera Vila, Ignasi2019-03-132019-03-132018-12https://hdl.handle.net/11299/202071University of Minnesota M.S. thesis.December 2018. Major: Applied Plant Sciences. Advisors: Neil Anderson, Mary Rogers. 1 computer file (PDF); iii, 66 pages.Urban agriculture refers to all agricultural activities that happen within the city limits. Traditionally, urban agriculture has been mostly a subsistence form of agriculture that allowed for vegetable self-assortment and occasional trade (Mougeot, 2005). In recent years, urban agriculture has gained in popularity to promote greener cities, ensure food security and healthy diets, and create new economic opportunities (Golden, 2013). Most of the world’s food production is consumed and transformed in the cities generating large amounts of organic waste. Urban agriculture has been proposed as a key activity to help recycle those nutrients present in that waste (Metson & Bennett, 2015; Smit & Nasr, 1992). Soilless systems allow urban growers to move agriculture into areas traditionally not used for production, such as rooftops, inside buildings, and parking lots. In some cases, building integration can improve overall efficiency, via increased insulation, CO2 enrichment, and water reuse (Buehler & Junge, 2016; Despommier, 2011; Sanyé-Mengual, Cerón-Palma, Oliver-Solà, Montero, & Rieradevall, 2015; Wortman, 2015). Wastewater in the US is mostly treated in a centralized manner with large amounts of energy used to aerate and remove carbon and nutrients present in the water. Irrigation with wastewater helps recycle nutrients and reduce water consumption. However, challenges to wastewater recycling include the presence of heavy metals and pathogens, especially if the treatment was improper. Decentralized treatment allows for water treated onsite. From and agricultural perspective, this allows a source of wastewater with higher nutrient load but devoid of pathogens and heavy metals presence (Libralato, Ghirardini, & Avezzù, 2012; Mohareb et al., 2017). Brewery industry produces large amounts of wastewater with a high carbon load and moderate presence of nutrients like nitrogen and phosphorus. In this project, an integrated pretreatment system is being developed where an encapsulated anaerobic digester reduces the carbon load of the brewery wastewater while producing hydrogen and methane, used to produce energy. The effluent from the digester is used for soilless urban agriculture to produce vegetables while reducing nutrient load. The final effluent may then be sent to the municipal treatment plant, with a much lower nutrient and carbon load that will require less energy for its treatment. The effluent was first used in hydroponic production growing Basil (Ocimum basilicum), and mustard greens (Brassica juncea), grown in a non-circulating individual hydroponic system. In both experiments, yield of the plants was compared to plants grown using inorganic fertilizer. Our results showed that plants grown with digested wastewater had lower yields as well as higher mortality. We attributed this to a low nutrient availability, nitrogen insufficiency, high electrical conductivity, and an unstable pH. In the following experiments ammonia was used in the digester to correct for pH instead of CaCO3 with the objective of increasing N content while maintaining low electrical conductivity. Two different substrate experiments were performed, in the first one Mustard greens were grown in four different substrates: peat-based, peat based mixed 50% (v/v) with fine sand, compost based, and compost based mixed 50% (v/v) with sand. In the second mustard greens, basil and lettuce (lactuca sativa) were grown in peat. In both experiment, four different fertility treatments were used: only water, water mixed with synthetic fertilizer, raw brewery wastewater and digested wastewater from the same brewery. In the first experiment results showed similar mustard greens yields with plants grown using inorganic fertilizer compared to plants grown with inorganic fertilizer, and no big differences among substrates. In the second , lettuce and mustard greens digested wastewater grown plants had similar than inorganic fertilizer while basil had lower yields. In conclusion, it is possible to create a decentralized system that combines anaerobic digestion with soilless urban agriculture reusing brewery effluent. Work cited: Buehler, D., & Junge, R. (2016). Global trends and current status of commercial urban rooftop farming. Sustainability (Switzerland), 8(11), 1–16. Despommier, D. (2011). The vertical farm: Controlled environment agriculture carried out in tall buildings would create greater food safety and security for large urban populations. Journal Fur Verbraucherschutz Und Lebensmittelsicherheit, 6(2), 233–236. Golden, S. (2013). Urban Agriculture Impacts : Social , Health , and Economic : A Literature Review Urban Agriculture Impacts : Social , Health , and Economic A Literature Review. University of California. Agriculture and Natural Resources, 1–22. Retrieved from Libralato, G., Ghirardini, A. V., & Avezzù, F. (2012). To centralise or to decentralise : An overview of the most recent trends in wastewater treatment management. Journal of Environmental Management, 94(1), 61–68. https://doi.org/10.1016/j.jenvman.2011.07.010 Metson, G. S., & Bennett, E. M. (2015). Phosphorus cycling in Montreal’s food and urban agriculture systems. PLoS ONE, 10(3), 1–18. https://doi.org/10.1371/journal.pone.0120726 Mohareb, E., Heller, M., Novak, P., Goldstein, B., Fonoll, X., & Raskin, L. (2017). Considerations for reducing food system energy demand while scaling up urban agriculture. Environmental Research Letters, 12(12). https://doi.org/10.1088/1748-9326/aa889b Mougeot, L. J. A. (2005). Agropolis: The Social, Political and Environmental Dimensions of Urban Agriculture. Agriculture. https://doi.org/10.1016/j.agee.2006.12.021 Sanyé-Mengual, E., Cerón-Palma, I., Oliver-Solà, J., Montero, J. I., & Rieradevall, J. (2015). Integrating Horticulture into Cities: A Guide for Assessing the Implementation Potential of Rooftop Greenhouses (RTGs) in Industrial and Logistics Parks. Journal of Urban Technology, 22(1), 87–111. Smit, J., & Nasr, J. (1992). Urban agriculture for sustainable cities: using wastes and idle land and water bodies as resources. Environment and Urbanization, 4(2), 141–152. Wortman, S. E. (2015). Crop physiological response to nutrient solution electrical conductivity and pH in an ebb-and-flow hydroponic system. Scientia Horticulturae, 194, 34–42.enBrewerySoilless productionUrban agricultureWastewater reuseThesis or Dissertation