https://ri.ufs.br/jspui/handle/riufs/19270 Fri, 17 Jul 2026 01:17:35 GMT 2026-07-17T01:17:35Z http://ri.ufs.br:80/retrieve/aef3c6ff-0b4d-486f-9b66-0f2addd49ac5/ppgecia.jfif https://ri.ufs.br/jspui/handle/riufs/19270 https://ri.ufs.br/jspui/handle/riufs/25250 Título: Tratamento primário da água produzida: coagulação lastreada com microareia e resíduos de crustáceos e moluscos Autor(es): Andonof, Mylena Torres Abstract: Produced water (PW), a byproduct of the oil and gas industry, has high levels of contaminants such as suspended solids, organic compounds, hydrocarbons, and heavy metals, representing a significant environmental challenge. Given legal requirements and growing concern about water pollution, the development of effective and sustainable technologies for its treatment is essential. In this context, this work aimed to evaluate the efficiency of coagulation ballasted with microsand and crustacean and mollusk waste (bioballast). The research was conducted in two stages: first, the produced water was characterized and the most efficient chemical coagulant was selected; second, the selected coagulant was applied to the coagulation/flocculation system with different ballast agents (microsand and bioballast). The produced water showed high concentrations of total suspended solids (TSS) and total oils and greases (TOG), exceeding the limits established by environmental legislation. For the coagulants tested (aluminum sulfate (AS), ferric chloride (FC), and aluminum polychloride (PAC)), aluminum sulfate, at a dosage of 0.2 g/L, stood out with removals of 72.86% for TSS and 91.24% for TOG, in addition to presenting the best cost-benefit ratio. The coagulation process ballasted with microsand (5 g/L) showed similar performance to the conventional process, with 74.35% for TSS and 91.77% for TOG. However, the use of bioballast at the same dosage resulted in a 7.23% increase in TSS removal and a 1.32% increase in TOG removal. Furthermore, metal analysis indicated that the bioballast did not adsorb Ba and Mn. However, bioballast presents itself as a sustainable and promising alternative to replace microsand as ballast, not only in the treatment of produced water, but also in the treatment of water and effluents, promoting the use of crustacean and mollusk waste and contributing to the development of cleaner technologies in effluent treatment. Thu, 18 Dec 2025 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/25250 2025-12-18T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25249 Título: Planejamento experimental aplicado à eletrocoagulação para o tratamento de esgoto doméstico Autor(es): Santos, Davi Nascimento dos Abstract: Given the growing need for environmental preservation and sustainable water management, this research addresses the application of electrocoagulation (EC) in the treatment of domestic sewage, focusing on the optimization of operational parameters through experimental design. Additionally, it aimed to evaluate the efficiency of organic matter removal using Central Composite Rotational Design (CCRD) to identify the optimal parameters for current density and pH. The characterization of the sewage was followed by the application of different EC configurations, resulting in significant removals of organic load and turbidity. The tests showed removals of up to 80.07% for BOD and 41.97% for COD in domestic sewage. Economic analysis indicated that the process is viable for smaller volumes of effluent, with a cost per cubic meter treated of $1.23 or R$6.20. The application of the method to different types of sewage demonstrated its robustness and flexibility, reinforcing the viability of EC as an effective and sustainable solution for sewage treatment. It is concluded that electrocoagulation can be an efficient alternative to improve water quality and promote public health in various communities. Wed, 28 Aug 2024 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/25249 2024-08-28T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/25248 Título: Otimização do processo de fermentação escura da vinhaça da cana-de-açúcar para produção de hidrogênio de baixo carbono Autor(es): Santos, Adrielle Silva dos Abstract: Sustainable energy production has gained prominence in recent years due to the intensification of climate change resulting from the predominant use of fossil fuels. In this context, the transition toward an energy matrix composed mainly of renewable sources has increased, and among the pathways pursued for this shift, hydrogen production stands out. Hydrogen is considered a clean energy source and a promising energy carrier, especially when produced from organic residues through biotechnological processes. The present study aimed to optimize the dark fermentation process in order to maximize fermentative hydrogen production using sugarcane vinasse as the substrate and sewage sludge as the inoculum. Pretreatments were applied to enhance the activity of hydrogen-producing microorganisms and to maximize the availability of readily fermentable sugars in the reaction system. The substrate was subjected to an acid pretreatment assisted by ultrasound (pH, temperature, and sonication time), while the sewage sludge underwent an acid/thermal pretreatment followed by incubation for 24 hours (pH 3.0 and incubation at 55 °C). Both residues were characterized in terms of their physicochemical parameters. Fermentations were carried out in a 7.5 L anaerobic bioreactor, and a factorial experimental design (2³) was employed to optimize the variables pH, temperature, and substrate/inoculum volumetric ratio. Gas quantification was performed using a gas chromatograph (GC-TCD/FID) based on the chromatographic method developed and validated in this study. The results confirmed the high energy potential of vinasse, resulting from its high load of biodegradable organic matter, as well as the efficiency of the pretreatment in increasing biodegradability and sugar availability. Based on the factorial experimental design, the optimized conditions for the variables were: pH 5.5, temperature 55 °C, and substrate/inoculum volumetric ratio of 50%, resulting in a maximum hydrogen production of 1104.4 N mL H₂ L⁻¹ substrate. Through the validation assay conducted under the optimized conditions, a maximum specific hydrogen production of 1158.6 N mL H₂ L⁻¹ substrate and an accumulated hydrogen production of 3267.6 N mL H₂ L⁻¹ substrate were obtained throughout the reaction process. These results demonstrate that the integration of pretreatments and optimized operational conditions enhances the dark fermentation process and maximizes hydrogen production, indicating that the proposed route can be considered a complementary alternative to the conventional hydrogen production pathway. Keywords: Sustainability, energy transition, biohyd Tue, 24 Feb 2026 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/25248 2026-02-24T00:00:00Z https://ri.ufs.br/jspui/handle/riufs/24616 Título: Avaliação ecotoxicológica do Bisfenol a e sua remoção em água utilizando a biomassa ativada de Ingá-cipó (Inga edulis) Autor(es): Lima, Lidivania Barbosa Abstract: Bisphenol A (BPA) is a substance used in the production of plastics and resins and is recognized for causing harmful effects on the environment and human health. As an endocrine disruptor, BPA can cause hormonal alterations, reproductive problems, and impacts on the growth and metabolism of aquatic organisms and humans. In this context, the search for effective strategies that enable its removal represents a current challenge. In this study, the toxicity of BPA to freshwater organisms was investigated before and after the application of adsorption techniques, using activated biomass from Inga edulis bark as the adsorbent material. Acute toxicity assays were conducted with Daphnia similis and Ceriodaphnia silvestrii to determine CE50 values (24 and 48 h), and with Chironomus sancticaroli to determine the CL50 (96 h). The mean CE50 values (24 and 48 h) for D. similis were 10.50 and 8.89 mg L⁻¹, respectively; for C. silvestrii, they were 5.64 and 3.63 mg L⁻¹, respectively; while for C. sancticaroli, the CL50 (96 h) was 3.32 mg L⁻¹. After determining the CE50 and CL50 values for BPA, the optimization of adsorption parameters was carried out, including kinetics, pH, isotherms, and optimal dosage. The biomass was previously characterized using SEM, FTIR, TG, CHN, BET, XPS, and point of zero charge (PZC) analyses, which confirmed structural modifications and the presence of functional groups relevant to the activation and adsorption processes. The adsorption assays demonstrated a significant reduction in BPA concentration in the samples, with removal efficiencies ranging from 38% to 61%. In addition, BPA concentrations before and after the adsorption process were quantified by electrochemical techniques and UV–Vis spectrophotometry. When the treated samples were re-exposed to the test organisms, survival rates of 100% for D. similis at 24 h and 80% at 48 h, 100% for C. silvestrii at both exposure periods (24 and 48 h), and 98% for C. sancticaroli at 96 h were observed, evidencing a substantial reduction in BPA toxicity after treatment. The results indicate that activated I. edulis bark biomass has high potential as an ecological and efficient adsorbent material, capable of significantly reducing BPA concentration and toxicity in aquatic environments, thus contributing to the development of sustainable alternatives for the treatment of contaminated waters. Wed, 05 Nov 2025 00:00:00 GMT https://ri.ufs.br/jspui/handle/riufs/24616 2025-11-05T00:00:00Z