Optimization of piggery wastewater treatment with purple phototrophic bacteria
The increase in human population in the world entails future challenges for the sustainable development of mankind. This demographic expansion will represent global changes generated by anthropogenic activity on planet Earth, involving negative impacts on the biosphere, atmosphere, cryosphere and hy...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universidad de Valladolid |
| Repositorio: | UVaDOC. Repositorio Documental de la Universidad de Valladolid |
| OAI Identifier: | oai:uvadoc.uva.es:10324/61050 |
| Acceso en línea: | https://doi.org/10.35376/10324/61050 https://uvadoc.uva.es/handle/10324/61050 |
| Access Level: | acceso abierto |
| Palabra clave: | Aguas residuales Wastewater Bacteria Bacterias 23 Química |
| Sumario: | The increase in human population in the world entails future challenges for the sustainable development of mankind. This demographic expansion will represent global changes generated by anthropogenic activity on planet Earth, involving negative impacts on the biosphere, atmosphere, cryosphere and hydrosphere. In particular, the hydrosphere will be affected by the increased contamination of surface water and groundwater, and an increase in their eutrophication due to inadequate management of wastewaters. Thus, the generation of new biotechnologies to reduce pollution and improve the sustainable development of humanity will be a challenge for the next few decades. In this sense, efficient wastewater treatment in cities, industry and agriculture requires the development of innovative solutions to reduce the pollution generated by the intense anthropogenic activity. Thus, the need for meeting the increasing demand for animal protein has led to an increase in intensive livestock farming, with the subsequent increase in the generation of wastewaters containing high organic matter, nitrogen and phosphorus concentrations. In particular, piggery wastewaters (PWW) are characterized by their high concentrations of organic matter and nitrogen in the form of ammonium, and by their odour nuisance. Traditionally, PWW has been treated by disposal in open anaerobic lakes, with the subsequent production of high concentrations of greenhouse gases such as CO2, CH4, NH3 and H2S to the atmosphere due to their open configuration. Another technology used for the treatment of this type of wastewaters is anaerobic digestion in enclosed bioreactors, which is capable of generating methane (CH4) as a byproduct, a gas with high economic and energy value. However, this process is only capable of removing the carbon present in PWW, generating an effluent with a high nitrogen and phosphorus content that is not assimilated in the process. Lastly, activated sludge systems entail an effective removal of carbon, nitrogen and phosphorous with a high energy demand and a destruction of the nutrients present in PWW. Nowadays, the use of photosynthetic microorganisms for PWW treatment at low operating costs and with a recovery of carbon, nitrogen and phosphorous has been proposed. These microorganisms are capable of absorbing solar radiation through the photosynthesis process to obtain energy, which is used for their growth and nutrients assimilation from different wastewaters. Purple phototrophic bacteria (PPB) represent the photosynthetic microorganisms with the most versatile metabolism in nature. PPB can grow phototrophically and chemotrophically, absorbing energy from solar radiation or from the degradation of organic compounds, respectively. In addition, PPB are heterotrophic microorganisms capable of degrading different organic compounds and also able to grow using an autotrophic metabolism, fixing carbon dioxide (CO2) and nitrogen (N2) from the atmosphere. PPB can grow both under anaerobic and aerobic conditions, through photoheterotrophy or chemoautotrophy, respectively. On the other hand, microalgae represent the most studied photosynthetic microorganisms in recent years, due to their high growth rate, capacity to fix CO2 and to the high valorization potential of their biomass. Both PPB and microalgae have species with extraordinary metabolic capacities, capable of growing at low or extremely high temperatures, under different pH ranges (acidic and alkaline), high salinity and in the presence or absence of oxygen, which supports their extraordinary metabolism for the treatment of multiple wastewaters. |
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