Simone Damasceno Gomes

1. The growing scarcity of fossil fuels, combined with the environmental impacts resulting from their combustion and the increasing global energy demand, has driven the search for alternative energ...

A oxidação anaeróbia de amônia (anammox), traz uma alternativa para o tratamento de resíduos contendo nitrogênio, sendo um dos compostos mais significativos em efluentes de agroindústrias. Apesar do potencial de tratamento e baixo custo, esse processo exige cuidados em torno de sua implantação, pois difere dos tratamentos convencionais que utilizam o ciclo bioquímico, necessitando de cuidados com fatores que influenciam na atividade microbiológica. Assim, o objetivo deste estudo foi avaliar o comportamento de um reator MABR, com lodo anammox, utilizando efluente sintético, frente a variação da temperatura e pH. O experimento dividiu-se em três fases, na fase I a operação ocorreu com uma temperatura de 30 °C e faixa de pH 8, na fase II a temperatura foi reduzida a 20 °C e mantida a faixa de pH 8, já na fase III a condução ocorreu com temperatura de 30 °C e faixa de pH 6. Os resultados indicaram que a eficiência do reator diminui em cada fase do experimento, sendo 94,60%, 63,40% e 23,79%, respectivamente para cada fase, além da redução do consumo específico de N-NH4+ ao decorrer do experimento. A variação da temperatura e pH resultou na desestabilização do processo anammox, ação indicada pelo consumo do OD e produção de N-NO3-. Concluiu-se que os parâmetros de operação, temperatura e pH, e outras condições como a disponibilidade de O2, necessitam de atenção na operação de reatores com processo anammox.

A indústria de abate e processamento de aves gera grandes volumes de efluentes com elevada carga orgânica e óleos e graxas. A digestão anaeróbia surge como uma alternativa eficiente para o aproveitamento energético desses resíduos, promovendo a conversão da matéria orgânica em biogás. Este estudo avaliou o desempenho de um reator anaeróbio em batelada sequencial com biomassa imobilizada (AnSBBR) na remoção de matéria orgânica e na produção de metano a partir da codigestão de lodo fresco do flotador e efluente bruto. O reator foi operado sob condições mesofílicas (30 ±1 °C) por 150 dias, submetido a diferentes cargas orgânicas volumétricas aplicadas (1,80, 0,9 e 1,57 gDQO/L.d), ajustadas conforme a variação na concentração afluente (3590,14, 2165,39 e 6378,61 mgDQO/L) e no tempo de ciclo (24, 48 e 24 h). A melhor performance foi obtida na condição III, com uma proporção de 20% de lodo fresco e 80% de efluente bruto, resultando em remoção de 90,43% da DQO total e 82,53% da DQO filtrada. O processo demonstrou estabilidade operacional, com teor médio de metano no biogás de 75%, vazão volumétrica de 797,00 mLCH₄.d⁻¹ e rendimento de 52.691,84 mLCH₄.gDQO⁻¹. Os resultados evidenciam o potencial da codigestão anaeróbia para o tratamento eficiente de efluentes avícolas, aliando a mitigação de impactos ambientais à valorização energética dos resíduos.

Anaerobic digestion is a versatile biotechnology because of the energy recovery from different kinds of waste. In addition to anaerobic digestion, there is the anaerobic co-digestion process, which improves the energy recovery of many kinds of waste in a single installation. The association of landfill leachate and crude glycerin is promising, considering the respective characteristics of each one. However, data about the anaerobic co-digestion of these substrates is still scarce. In this context, the present study aimed to evaluate the effect of the factors: incubation time (20-40 days), pH (7-8), glycerol proportion (0.5-2.5% v/v) and substrate/inoculum ratio (0.2-0.6 g COD g-1 VSS) by Plackett-Burman statistical design of experiments. The advantages of anaerobic co-digestion were evaluated achieving the highest treatment performance of 98.1% efficiency of organic matter removal, and a high methane content in the biogas of approximately 79%. Furthermore, a positive effect of the key factor incubation time and glycerol proportion, instead of the substrate/inoculum ratio, which requires low values. Overall, the following parameters: incubation time, glycerol proportion and S/I ratio highlighted their significant effect in the bioprocess performance.

The biofertilizer segment stabilized in anaerobic digesters offers a promising solution for reducing reliance on imported products. However, the development of this sector is largely constrained by logistical challenges, as well as the cost and feasibility of processing, transporting, and distributing organic fertilizers. To address these issues, this research presents a comprehensive thermoeconomic study of four scenarios applied in a rural microgeneration power plant in Toledo, Paraná state, Brazil. The main objectives were to determine the cost of the primary products, evaluate the system’s potential for energy self-sufficiency, and assess its economic viability. These findings would help amortize the costs associated with installing and operating the technology while adding greater value to its by-products. In the thermodynamic analysis, the potential for electricity generation from swine residues was evaluated. The economic analysis used the net present value, internal rate of return, payback period, and levelized costs of both energy and biofertilizer. By comparing the energy consumption required to fertigate 1 m³ of swine manure with its electricity generation potential, the system could achieve energy self-sufficiency. Moreover, the economic indicators of the scenarios demonstrate their viability, driven by the sale of electricity, transportation services, and biofertilizers.

This study promoted the autotrophic denitrification of poultry slaughterhouse wastewater in anoxic reactor with fix bed of elementary sulfur a dolomitic limestone and, posteriorly, nitrification was coupled to this system in an anoxic-aerobic reactor. The anoxic reactor was operated under constant nitrogen concentration of 71,1±4,2 mg NOx L-1 and HTR of 14, 10 and 6 hours. In this reactor, the efficiencies and denitrification tax obtained were 94,4±2,0, 94,9±2,3 and 71,1±7,8%, for the HRT of 14, 10 and 6 hours, respectively. The reactor anoxic-aerobic was operated with HRT of 16 hours and fed with effluent in rate ammonified: nitrified of 3:1 (E1), 1:1 (E2) and 1:3 (E3). In this reactor, the efficiencies of ammoniacal nitrogen removal and total nitrogen removal were 67,3±6,4, 63,4±6,7 and 14,2±4,4% and 64,2±6,3, 53,1±7,1 and 33,8±1,7%, to the conditions E1, E2 and E3, respectively. The application of autotrophic denitrification from the elementary sulfur can be considerate a viable technology in wastewater nitrified treatment.

Autotrophic denitrification from elemental sulfur is an alternative to heterotrophic denitrification for substrates with a low C/N ratio. In this process, nitrogen compounds are reduced from elemental sulfur instead of carbon, as in the conventional process. However, it may be limited by the low concentration of alkalinity in these effluents. Thus, this study evaluated the performance of autotrophic denitrification of nitrified poultry effluent in four fixed bed reactors with a ratio of elemental sulfur/dolomitic limestone (1:0, 3:1, 1:1, 1:3 v/v) under conditions of the decline of initial alkalinity (1000, 800, 600, 400 and 200 mg CaCO3 L-1). Denitrification efficiencies greater than 84.8% were observed in conditions of initial alkalinity greater than 600 mg CaCO3 L-1 in the four reactors, associated with maximum yields of 445.1 mg SO4-2 L-1. The slow dissolution of dolomitic limestone may have impaired denitrification efficiency in conditions of initial alkalinity lower than 600 mg CaCO3 L-1. The autotrophic denitrification process proved viable for the treatment of nitrified effluent, and its efficiency was linked to the food substrate and the dissolution of dolomitic limestone.

Species of the genus Podocarpus L’Hér. ex Pers.present biological activities, such as analgesic, antioxidant, antifungal, acting in the fight against anemia, depurative and fortifying. Podocarpus lambertii Klotzch ex Endl. is a Brazilian native species popularly known as maritime pine and lacks information about its phytochemical profile and possible biological activities. The study was conducted to determine the phytochemical composition of soluble plant extracts of acetone (EA), ethyl acetate (EAE) and hexane (HE) from leaves of P. lambertii; evaluate the antimicrobial potential by the broth microdilution technique; antioxidant potential by the DPPH method, as well as to evaluate the biofilm inhibition capacity by the crystal violet assay and reduction of the yellow tetrazolium salt (MTT). Phytochemical screening detected the presence of flavonoids, triterpenoids, steroids, tannins, alkaloids and saponins. All extracts showed antimicrobial activity on the microorganisms tested, and the EA showed the best results. High free radical scavenging potential was observed only in EAE (96.35%). The antibiofilm potential was observed in the EAE extract. The results contribute to the knowledge of the species and indicate the potential of P. lambertii extracts as a source of plant bioactives for the development of new alternative strategies to control resistant microorganisms.

The continuous multiple tube reactor (CMTR) has been developed as a promising technology to maximize biohydrogen production (BHP) by dark fermentation (DF) by preventing excess biomass accumulation, leading to suboptimum values of specific organic loading rates (SOLR). However, previous experiences failed to achieve stable and continuous BHP in this reactor, as the low biomass retention capacity in the tube region limited controlling the SOLR. This study goes beyond the evaluation of the CMTR for DF by inserting grooves in the inner wall of the tubes to ensure better cell attachment. The CMTR was monitored in 4 assays at 25ºC using sucrose-based synthetic effluent. The hydraulic retention time (HRT) was fixed at 2 h, while the COD varied between 2–8 g L⁻¹ to obtain organic loading rates in the 24 – 96 g COD L⁻¹ d⁻¹. Long-term (90 d) BHP was successfully attained in all conditions due to the improved biomass retention capacity. Optimal values for the SOLR (4.9 g COD g⁻¹ VSS d⁻¹) were observed when applying up to 48 g COD L⁻¹ d⁻¹, in which BHP was maximized. These patterns indicate a favorable balance between biomass retention and washout was naturally achieved. The CMTR looks promising for continuous BHP and is exempt from additional biomass discharge strategies.

Curcuma longa is a plant that has stood out in research evaluating antimicrobial, anti-inflammatory, antiprotozoal, anticarcinogenic and antifungal activity. The discovery of new alternatives for the development of drugs originating from active principles of plants is necessary considering the high adaptive capacity of different microorganisms. Thus, the present study aimed to evaluate the antimicrobial activity of extracts of oleoresin and powder suspension of rhizomes of Curcuma longa against the bacterium Escherichia coli. In this study, no antimicrobial activity was observed for the extracts of turmeric powder and oleoresin against Escherichia coli. There is a wide variety of results obtained in the literature in the face tests of C. longa on the different microorganisms, some positive, demonstrating antimicrobial action, and others negative. This divergence is justified by factors such as: different methodologies used, climate, soil types, fertilization, water availability of the plant’s cultivation, as well as the form of harvest and storage, which interfere in the components present and in their concentration in the plant. Although the results of this study were negative, it does not mean that the plant does not have antimicrobial activity, being indicated the continuity in the assays, aiming to identify the factors that generate disagreement between the studies already carried out.