The Future of Urine Diversion - An Australian context

With world population expected to reach 9 billion people by 2050, global food production might need to rise by up 70 %. This will require even more extensive use of fertilizers than today. In the wake of an emerging climate crisis the need for biofuels will also increase and further exacerbate the nutrient demand. Most conventional fertilizers are today produced in an unsustainable way and minerals such as phosphorus and potassium that are essential to crop growth are non renewable. This calls for a need to find alternative nutrient sources. From the wastewater stream nutrients can be recycled in various ways. One way is to separate the urine at source in the toilet before it gets in contact with faeces. This way the urine can be used as a sterile and versatile fertilizer containing all of the essential nutrients. Urine diversion has been compared to spreading, precipitation and incineration of sewage sludge in terms of environmental and economic benefits. Urine diversion performs well compared to these other methods when it comes to environmental benefits, but it is still hard to make it economically viable. This thesis examines the drivers and barriers that could promote or hamper the development of urine diversion and compare Sweden to Australia in terms of energy, agriculture and environment. A urine diversion trial at Kinglake, Victoria, Australia has been studied in order to explore the future of urine diversion in Australia. Australia is an agriculture country with high export of agriculture goods, but it lacks policies that promote recovery of nutrients. At present it is more likely to find support for urine diversion in Australian environmental policies. Even if urine diversion has been around globally for a long time, the industry has still not developed adequate products to make it gain foothold because of a poorly defined market. These are among the key issues to address when implementing urine diversion in Australia.Med en global befolkning som väntas nå 9 miljarder människor 2050 kommer det eventuellt att behöva produceras upptill 70 % mer mat än idag. Detta kommer att kräva ännu mer omfattande användning av gödningsmedel. I kombination med en växande klimatkris kommer behovet av biobränslen också att öka och ytterligare höja efterfrågan på näringsämnen. De flesta konventionella gödningsmedel produceras idag på ett ohållbart sätt och mineraler såsom fosfor och kalium, som är nödvändiga för grödors tillväxt är icke förnybara. Detta kräver att vi hittar alternativa näringskällor. Från avloppsvattenströmmen kan näringsämnen återvinnas på olika sätt. Traditionellt har detta gjorts genom att sprida hygieniserat avloppsslam på jordbruksmark, men oron för tungmetaller i slammet begränsar användningen. För att undvika spridning av tungmetaller, kan slammet antingen förbrännas eller fällas ut, men dessa båda metoder innebär förluster av näringsämnen. Vilken metod som används beror mycket på de lokala förhållandena och lagstiftning. Ett alternativt sätt är att separera urin vid källan, dvs. i toaletten innan det kommer i kontakt med avföringen. På så sätt kan urinen användas som ett sterilt och mångsidigt gödningsmedel som innehåller alla näringsämnen växter behöver, men nästan inga tungmetaller. När man jämför dessa metoder för näringsåterföring vad gäller miljömässiga och ekonomiska fördelar, står sig urinseparation väl när det gäller miljöfördelar, men är fortfarande svårt att göra det ekonomiskt gångbart. Australien är ett jordbruksland med hög export av jordbruksvaror, men det saknas policys som främjar återvinning av näringsämnen. I dagsläget är det mer sannolikt att hitta stöd för urinseparation i australisk miljöpolitik än från jordbrukshåll. Trots att urinseparation har funnits globalt under en lång tid, har branschen fortfarande inte utvecklat lämpliga produkter som kunnat ge tekniken fotfäste, mycket på grund av en dåligt definierad marknad. Dessa är bland de viktigaste frågorna att ta itu med för att kunna göra urinseparation gångbart i Australien. Det står klart att urin kan användas som ett bra och säkert komplement till konventionella gödningsmedel, men för att lyckas med urinseparation krävs ett tvärvetenskapligt tillvägagångssätt som inte bara behandlar de vetenskapliga aspekterna, utan även de praktiska detaljerna, information och attityder samt lagstiftning och strategiskt beslutsfattande

The Future of Urine Diversion - An Australian context

With world population expected to reach 9 billion people by 2050, global food production needs to rise by up 70 %. This will require even more extensive use of fertilizers. In the wake of an emerging climate crisis the need for biofuels will also increase and further exacerbate the nutrient demand. Most conventional fertilizers are today produced in an unsustainable way and minerals such as phosphorus and potassium that are essential to crop growth are non renewable. This calls for a need to find alternative nutrient sources. From the wastewater stream nutrients can be recycled in various ways. One way is to separate the urine at source in the toilet before it gets in contact with faeces. This way the urine can be used as a sterile and versatile fertilizer containing all of the essential nutrients. This thesis examines the drivers and barriers that could promote or hamper the development of urine diversion. A urine diversion trial at Kinglake, Victoria, Australia has been studied in order to explore the future of urine diversion in Australia.With world population expected to reach 9 billion people by 2050, global food production needs to rise by up 70 %. This will require even more extensive use of fertilizers. In the wake of an emerging climate crisis the need for biofuels will also increase and further exacerbate the nutrient demand. Most conventional fertilizers are today produced in an unsustainable way and minerals such as phosphorus and potassium that are essential to crop growth are non renewable. This calls for a need to find alternative nutrient sources. From the wastewater stream nutrients can be recycled in various ways. One way is to separate the urine at source in the toilet before it gets in contact with faeces. This way the urine can be used as a sterile and versatile fertilizer containing all of the essential nutrients. This thesis examines the drivers and barriers that could promote or hamper the development of urine diversion. A urine diversion trial at Kinglake, Victoria, Australia has been studied in order to explore the future of urine diversion in Australia

Simulation of ethanol production processes from sugar and sugarcane bagasse, aiming process integration and maximization of energy and bagasse surplus

Orientadores: Rubens Maciel Filho, Carlos Eduardo Vaz RossellDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuimicaResumo: O objetivo desta dissertação é apresentar a descrição e a simulação de processos de produção de etanol a partir do caldo e do bagaço da cana-de-açúcar, visando o levantamento do consumo de energia destes processos. Foram consideradas melhor ias no processo convencional de produção de etanol a partir do caldo, tais como a realização de eficientes tratamento e esterilização do caldo, a condução da fermentação a temperaturas mais baixas (28°C) do que as utilizadas atuamente, o estudo de configuração de destilação duplo efeito e a otimização de processos de desidratação para produção de etanol anidro. O processo de produção de etanol a partir do bagaço da cana-de-açúcar é baseado em um processo de hidrólise do tipo Organosolv com ácido diluído em três etapas: pré-hidrólise da hemicelulose, deslignificação Organosolv e hidrólise da celulose. Considerando-se a utilização de 70 % do bagaço gerado nas moendas como matéria prima do processo de hidrólise estudado, seria possível aumentar a produção de etanol em cerca de 17 %, considerando somente a fermentação das hexoses obtidas a partir da celulose do bagaço. A realização do processo de hidrólise leva a um aumento do consumo de energia do processo, que pode ser compensado pela otimização do processo convencional de produção .de etanol a partir do caldo da cana-de-açúcar, do aproveitamento da palha e de subprodutos do processo de hidrólise como a lignina, e da integração térmica do processo integrado, que utiliza caldo e bagaço como matéria prima para produção de etanol. O equacionamento do consumo energético da produção integrada de etanol a partir da cana-de-açúcar e do bagaço de cana-de-açúcar constitui um obstáculo à viabilização técnica e econômica do processo de hidrólise. Este trabalho visa apresentar então colaborações no sentido de superar este obstáculo, considerando-se a produção de etanol a partir do bagaço de cana-de-açúcar por meio de um processo de hidrólise do tipo Organosolv com ácido diluídoAbstract: The main objective of this dissertation is to present the description and simulation of bioethanol production processes from sugarcane juice and bagasse, considering the evaluation of energy consumption. Some improvements were considered for the conventional bioethanol production process from sugarcane juice, such as efficient juice treatment, sterilization and concentration, lower fermentation temperatures (28°C) than the ones used nowadays in the industry, study of a double effect distillation sys tem and optimization of dehydration processes for anhydrous bioethanol production. The process considered for bioethanol production from sugarcane bagasse is based on an Organosolv process with dilute acid hydrolysis, carried on three non-simultaneous steps: prehydrolysis of hemicellulose, Organosolv delignification and cellulose hydrolysis. The use of 70 % of sugarcane bagasse generated on the mills as raw material for the hydrolysis process allows an increase in bioethanol production of 17 %, considering exclusively the fermentation of the hexose obtained from the cellulose fraction of sugarcane bagasse. An increase on energy consumption is observed when bagasse is used as raw material in the hydrolysis process, but it may become feasible considering the optimization of conventional bioetlJ.anol production process, the use of sugarcane trash and lignin as fuel in boilers and the thermal integration of the integrated process, which uses sugarcane juice and bagasse as raw materiaIs for bioethanol production. Evaluation of the energy consumption of the integrated production of ethanol from sugarcane and sugarcane bagasse constitutes an obstacle for the technical and economical feasibility of the hydrolysis processo This work aims to present contributions to help surpass this obstacle, considering the production of ethanol from sugarcane bagasse using an Organosolv process with dilute acid hydrolysisMestradoDesenvolvimento de Processos QuímicosMestre em Engenharia Químic

Direct Solar Absorption Nanofluids for Forward Osmosis Desalination

Solar energy is the most abundant and easily accessible source of renewable energy, however, its efficient use is not an easy task. Absorption of solar energy directly by the working fluid is an emerging trend in solar collection, known as direct solar absorption. On the other hand, almost one-third of the world population is living in water stressed conditions and this figure is expected to continuously increase in next a few decades. Desalination of sea and brackish water and reclamation of wastewater is being progressively practiced worldwide through different techniques. Forward osmosis (FO) is an emerging desalination technology, which operates under an internal osmotic gradient across the FO membrane. The lack of proper draw solutions with high osmotic pressure, minimum reverse solute flux and easy regeneration properties, however, limits the FO’s development. This work develops a novel concept of combining solar energy, nanoparticles and FO to produce potable water suitable in arid areas, far away from the grids. Two independent functions i.e. osmotic pressure and direct solar absorption, are integrated for the first time into purposely formulated nanofluids for FO solar desalination. The direct solar absorptive nanofluid based novel draw solutions (NDS) are aimed at developing high osmotic pressure for enhanced water flux across FO membrane and, at the same time, to absorb solar energy efficiently for their regeneration. A number of nanofluids were formulated and characterized in terms of their morphologies, structures and elemental compositions. The characterized nanofluids were investigated experimentally for their direct solar absorption behaviour and FO performance. A unique hybrid of direct absorptive nanofluid and osmotically active matters was developed that sufficiently performed the proposed two functions in FO solar desalination. The photothermal conversion performance of engineered NDS was examined under a solar simulator and the results revealed the influence of nanoparticle type and concentration. The inclusion of low concentrations of nanoparticles could improve solar capture significantly. In direct solar absorption and steam generation experiments, nine nanofluids were examined and an enhancement in bulk photothermal efficiency (PTE) of about 95%, 100% and 105% over the base fluid was observed with gold, silver and carbon nanofiber (CNF) nanofluids respectively. The most absorptive carbon nanofiber based nanofluid was surface functionalized for osmotic pressure enhancement and experimented as NDS for FO performance in terms of osmotic pressure, water flux, reverse solute flux and water recovery. The NDS developed sufficient osmotic pressure and an enhancement of 80% in water flux was observed over 1M salt solution used as reference. The reverse solute flux of the NDS was negligible and the quality of product water was within the potable water standards. The experimental results showed that the proposed novel draw solutions can sufficiently develop osmotic pressure to permeate water across the FO membrane and in the same time, significantly enhance the potable water generation using solar energy. Moreover, the quality of produced water suggested that these novel draw solutions could be potential candidates for future FO desalination in arid areas by using the energy from the Sun

Energy: A continuing bibliography with indexes, issue 31

This bibliography lists 1111 reports, articles, and other documents introduced into the NASA scientific and technical information system from July 1, 1981 through September 30, 1981

Nutrient recovery from bio-digestion waste: from field experimentation to model-based optimization

The increasing awareness of natural resource depletion, the increasing demand of nutrients and energy for food production, and the more and more stringent nutrient discharge and fertilization levels, have resulted in an increased attention for nutrient recovery from municipal and agricultural wastes. This PhD dissertation aims at stimulating the transition to a bio-based economy by providing (tools to develop) sustainable strategies for nutrient recovery from organic wastes following bio-energy production through anaerobic digestion (= bio-digestion waste). Particular attention is paid to the valorization of the recovered products as renewable substitutes for chemical fertilizers and/or as sustainable organo-mineral fertilizers in agriculture. Three complementary research phases were conducted: 1) technology inventory and product classification, 2) product value evaluation, 3) process modelling and optimization. In the first phase, a systematic technology review and product classification was performed. In phase 2, product characterizations and mass balance analyses at full-scale waste(water) resource recovery facilities (WRRFs) were executed. An economic and ecological evaluation of different bio-based fertilization scenarios was conducted and the most sustainable scenarios were selected for subsequent agronomic evaluation at field and greenhouse scale. In phase 3, a generic nutrient recovery model library was developed aiming at fertilizer quantity and quality as model outputs. Increased insights in unit process performance and interactions were obtained through global sensitivity analyses. The models were successfully used as a tool for treatment train configuration and optimization. Based on all acquired knowledge, a generic roadmap for setting up nutrient recovery strategies as function of fertilizer markets, legislations, and waste characterization was established. As such, the present dissertation further develops the concepts of maximally closing nutrient cycles in a cradle-to-cradle approach. The work reveals important evidence of the positive impact of recovered products on the economy, agronomy, and ecology of intensive plant production. Moreover, it provides the fundamental information and tools to facilitate the implementation and optimization of sustainable nutrient recovery strategies. All of this may open up new opportunities for sustainable and more bio-based economic growth and thus create a win-win situation for the environment, the society, and the economy in Belgium, Canada, and beyond