Potential of duckweed for swine wastewater nutrient removal and biomass valorisation through anaerobic co-digestion

Over the last decades, phytodepuration has been considered an efficient technology to treat wastewaters. The present study reports a bench scale depuration assay of swine wastewater using Lemna minor. The highest observed growth rate obtained in swine wastewater was 3.1 ± 0.3 gDW m−2 day−1 and the highest nitrogen and phosphorus uptake were 140 mg N m−2 day−1 and 3.47 mg P m−2 day−1, respectively. The chemical oxygen demand removal efficiency in the swine wastewater assay was 58.9 ± 2.0%. Furthermore, the biomass valorisation by anaerobic co-digestion with swine wastewater was assessed. Results showed a clear improvement in specific methane production rate (around 40%) when compared to mono-substrate anaerobic digestion. The highest methane specific production, 131.0 ± 0.8 mL CH4 g−1 chemical oxygen demand, was obtained with a mixture containing 100 g of duckweed per liter of pre-treated swine wastewater. The water-nutrients-energy nexus approach showed to be promising for swine waste management.info:eu-repo/semantics/publishedVersio

Avaliação de prédios urbanos a reabilitar ocupados parcial ou totalmente por inquilinos

Com esta dissertação pretende-se abordar as questões relacionadas com o investimento na reabilitação de edifícios antigos, cujas fracções constituintes se encontram parcialmente ou na sua totalidade ocupadas por arrendatários. Numa primeira fase, do presente trabalho, é caracterizado o sistema construtivo dos edifícios antigos, bem como as anomalias existentes e possíveis intervenções. Numa segunda fase é caracterizado o investimento na reabilitação de edifícios antigos, com algumas ou com a totalidade das suas fracções constituintes com contratos de arrendamento também antigos

Can Escaping From Poor Neighborhoods Increase Employment and Earnings?

Examines whether families who moved to lower poverty areas through the Moving to Opportunity program benefited from more opportunities for employment and higher earnings, what factors affected outcomes, and how relocation intervention could be improved

La mortalidad de las empresas familiares ecuatorianas por falta de planificación sucesoria

Ecuadorian family businesses contribute to the development of the country and are job generators. Despite their importance, no legal regulations have been established that comprises fully the complexity of these type of companies and they have had to adapt to their environment. In the present study, the flawed regulations that the legislation on succession has are presented in order to understand the early mortality of this type of companies that cannot achieve a full generational transition in their chain of management, due to not having a well stablished succession plan that allows the predecessors to transmit his business legacy to his successors with an organized, defined and legally adequate mechanism that aligns to the challenges they must face at any time. In the introduction, studies related to the subject and their approaches are summarized. This research takes a perspective of law and expresses the legal and conceptual aspects of the lack of a succession plan that could allow for succession to be sustainable over time and generations. The methodology is a non-experimental qualitative approach, using documentary, bibliographic, Constitutional and legal instruments through a socio-legal method. Obtaining as a result that the lack of succession planning is one of the reasons for the mortality of this type of companies. In relation to the discussion and conclusion, public policies are needed where the State establishes mechanisms so that these companies do not disappear in generational changes. Its growth and development not only requires an organizational structure, it must understand generational change as success that can happen at any time, so it is necessary to have a succession plan that supports it.Las empresas familiares ecuatorianas, contribuyen al desarrollo del país y son generadores de empleos. A pesar de la importancia que tienen no se ha establecido de manera integral normativa jurídica al respecto y han tenido que adaptarse a su entorno. En el presente estudio se articula la normativa dispersa que tiene la legislación sobre la sucesión para poder entender la mortalidad temprana de este tipo de sociedades que no pueden alcanzar la trasmisión generacional, por no contar con una planificación sucesoria perfectamente determinada que permite a los antecesores trasmitir su legado empresarial a sus sucesores de manera organizada, definida y jurídicamente adecuada a los requerimientos y especiaciones de las empresas familiares que deben afrontar en cualquier instante. En la introducción, se recogen estudios relacionados al tema desde otros enfoques, mientras que esta investigación es desde la perspectiva del derecho, para lo cual se expresan aspectos jurídicos y conceptuales de carecer de un plan sucesorio que permita mantenerse en el tiempo por generaciones. La metodología utilizada es con enfoque cualitativo del tipo no experimental, empleando los instrumentos documentales, bibliográficos, Constitucionales y legales a través del método socio-jurídico. Obteniendo como resultado que la falta de planificación sucesoria es una de las razones de mortalidad de este tipo de empresas. En relación a la discusión y conclusión se necesita políticas públicas, donde el Estado establezca mecanismos para que estas empresas no desaparezcan en los cambios generacionales. Y que para su crecimiento y desarrollo no solo se requiere de una estructura organizacional, debe reaccionar frente al relevo generacional como un cambio que se puede producir en cualquier momento por lo que se requiere tener un plan sucesorio que lo sustente

Winery Wastewater Treatment - Evaluation of the Air Micro-Bubble Bioreactor Performance

The wine sector has faced increasing pressure in order to fulfill the legal environmental requirements, maintaining a competitive position in a global market. The rising costs associated have stimulated the sector to seek sustainable management’s strategies, focussing on controlling the demand for water and improving its supply.Some EU Directives were implemented concerning water protection and management. These included in particular the Framework Directive in the field of water policy and environmental legislation about specific uses of water and discharges of substances.Several winery wastewater treatments are available, but the development of alternative technologies is essential to increase their efficiency and to decrease the investment and exploration costs.The main goals of the present paper are the comparison of different biological treatment systems, in particular fixed and suspended biomass, operating under aerobic conditions. Since the accurate design of the bioreactor is dependent on many operational parameters, aspects related to hydraulic retention time; oxygen mass transfer and contact time, energetic costs; sludge settling and production; response time during startup, flexibility and treated wastewater reuse, in crop irrigation, with the aim of closing the water cycle in the wine sector, will be addressed. A new treatment system will be presented as a case study, an air micro-bubble bioreactor (AMBB), that will highlight the advantages and constraints on its performance at bench-scale and full-scale, in order to fulfill the gaps associated with the implemented winery wastewater treatment systems. The data presented was collected during four years monitoring plan and used to develop a tool to support the selection of the best available technology. The present study will also contribute to the implementation of an integrated strategy for sustainable production in the wine sector, based on a modular and flexible technology that will facilitate compliance with environmental regulations and potential reuse for crop irrigation. This approach will contribute to the development of a bio-based economy in the wine sector that should be integrated in a Green Innovation Economy Cycle.Fundação para a Ciência e a Tecnologia (FCT

Performance study for membrane fractionation of second cheese whey from sheep

Second ovine cheese whey (SCW) is a by-product resulting from the production of sheep whey cheeses, by thermal aggregation of whey proteins. Its nutritional value is high because it contains about half of the soluble protein that is present in the original whey, free amino acids, small peptides, lactose, oligosaccharides, vitamins and minerals. However, despite high volumes generated (about 18 L of SCW by kg-1 of whey cheese produced), SCW is not recovered, causing problems in water treatment plants due to its high biological oxygen demand (BOD5) and chemical oxygen demand (COD), about 10,200 mg O2 L-1 and 69,500 mg O2 L-1, respectively. In order to valorize this by-product, the performance of a sequence of membrane processes, namely wide ultrafiltration (UF1), tight ultrafiltration (UF2) and nanofiltration (NF) was evaluated. In our previous work, we selected a wide ultrafiltration membrane of cellulose regenerated acetate, RC70PP with a nominal cut-off (MWCO) of 10 kDa) and hydrophilic characteristics, for recovering protein fraction. In this work, the membrane was used to concentrate SCW till a volume concentration factor (VCF) of 3.0. The permeates were then subjected to a second UF with a tight UF membrane (MWCO of 1 kDa), ETNA01PP, till a VCF of about 2.5. ETNA01PP is a surface-modified poli(vinylidene fluoride (PVDF) membrane, with hydrophilic characteristics. Nanofiltration of permeates of the second UF was performed using a membrane made of polypiperazine amide, NF99, till a VCF of 2.5. In all experiments, the membrane area used was 0.072 m2. Both ultrafiltration processes were carried out at a transmembrane pressure of 2.0 bar, whereas nanofiltration was realized at a transmembrane pressure of 20.0 bar. The feed flow rate was kept at 0.92 m s-1, in all experiments. Results showed that during UF1 and UF2, permeate fluxes decreased about 22%, while in NF experiments a sharp decrease occurred (about 50%), till the VCF studied (Fig.1), perhaps due to scaling on the membrane. Please click Additional Files below to see the full abstract

Enhancement of sewage sludge bioconversion to methane by addition of exhausted coffea biowaste liquid fraction

Original PaperAnaerobic co-digestion of organic rich wastes and wastewater sludge has become an attractive economic possibility for water utilities as it enhances biogas production. The suitability of the organic rich waste depends on its biodegradability as well as on its synergetic effect on the anaerobic digestion process. The feasibility of sewage sludge (SS) treatment via co-digestion was studied in a semi-continuous mode at mesophilic conditions (36 ± 1 °C), with a hydraulic retention time of 17 days and an average organic loading rate of 0.94 ± 0.05 gVS Lreactor day− 1, using the liquid fraction of pre-treated exhausted coffee biowaste (LECB) as a co-substrate. An anaerobic co-digestion trial (T1) was performed using as feeding mixture 80% SS and 20% LECB (v:v) and compared against a reference scenario of mono-digestion of SS (T0). The stability along assays was ensured by monitoring the digestate characteristics (pH, electrical conductivity, total alkalinity and ammonia content) and the specific energy-loading rate (SELR). Along the operation time of T1, methane yield and VS removal were significantly higher in comparison to mono-digestion of SS. Results showed that the addition of the co-substrate had a positive effect on specific methane production (3 times higher) and methane content (12% higher), indicating this is a feasible strategy towards self-sufficient wastewater treatment plantsinfo:eu-repo/semantics/publishedVersio

Integrated renewable energy systems in fruit and vegetable processing industries: a systematic review

Review ArticleThe exponential population growth will put great pressure on natural resources, agriculture, energy systems and waste production. New business models and innovative technological approaches are necessary to tackle these challenges and achieve the energy transition targets set by the European Commission. Renewable energy technologies and processes such as solar photovoltaic, solar thermal and anaerobic co-digestion have become a subject of interest and research as a solution that could be fully implemented in industries and solve several environmental and economic problems. This paper discusses the possibility of integrating and complement these technologies to maximize renewable energy production and circularity. The review was performed with a funnel approach aiming to analyze broad to specific subjects. Beginning with a literature review on the various definitions of circular economy, bioeconomy, and circular bioeconomy, ultimately proposing a single definition according to an industrial and academic scope combination, followed by a systematization and assessment of data and literature regarding energy systems present state and projections. The next phase was to assess data and literature of the fruit and vegetable processing industry from an energy consumption and biowaste production perspective to consequently discussing technologies that could help manage problems identified throughout this review. This paper culminates in propounding an Integrated Renewable Energy System conceptual model that promotes energy and waste circularity, envisioning how industries could be designed or redesigned in the future, coupled with a circular bioeconomy business modelinfo:eu-repo/semantics/publishedVersio