Browsing by Author "Grabowski, Thais Theomaris dos Santos"
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- Eco-friendly cement mortar with wastewater treatment plant sludge upcyclingPublication . Grabowski, Thais Theomaris dos Santos; Pietrobelli, Juliana Martins Teixeira; Martins, RamiroThis study aimed to investigate the technical feasibility of replacing cement in mortar production with sludge generated in wastewater treatment plants (WWTPs), prepared using different treatments. The sludge used in the experiments was processed using four different methods to investigate the effect of processing on the mechanical strength of the specimens. The sludge was then mixed with mortar in different proportions, and samples were produced for flexural and compressive strength tests. The results showed that specimens with 7% sludge from the burned treatment exhibited the highest resistance, surpassing the standard. Specimens with sludge from the drying treatments showed similar results. This study found that using sludge in mortar production could lead to energy savings compared to traditional cement production methods. Moreover, the incorporation of sludge resulted in mortars that met the specifications of the EN 998-1:2018 standard, thereby indicating their technical feasibility. Therefore, this study demonstrated the potential of using sludge from WWTPs as a substitute for cement in mortar production, which could contribute to the reduction in the environmental impacts caused by civil construction and the development of sustainable alternatives for the disposal of sludge generated in WWTPs.
- Eco-friendly cement mortar with WWTP sludge recoveryPublication . Grabowski, Thais Theomaris dos Santos; Martins, Ramiro; Pietrobelli, Juliana Martins TeixeiraThe increase in sludge generation in wastewater treatment plants (WWTP) makes sludge management a difficult task so that it is necessary to create alternatives for the final sludge disposal. The mineralogical characteristics of the sludge allow it to be applied to construction materials. The construction industry is the one that most exploits and consumes natural resources and uses energy intensively, thus generating quite considerable environmental impacts. Creating sludge utilisation techniques in the construction industry provides a safe and stable destination for sludge and contributes to reducing the environmental impacts that the construction industry already has. Thus, the general objective of this project was to evaluate the technical feasibility and economic valuation of the use of WWTP sludge for partial replacement of cement in the production of mortar. For the study, sludge was collected from the WWTP in Bragança, and it was characterised by pH, humidity, total solids, and organic matter content. Different methods (5) were used to prepare the sludge for the mortar. Mortars were produced with 0 (standard, reference mortar), 3, 5, 7 and 10% replacement of cement by treated sludge. With the manufactured mortar, specimens were moulded to test the resistance to flexion and compression. Mortar with 7% sludge ash showed greater resistance than standard mortar, only mortars with wet oxidised sludge showed a resistance rating lower than standard mortar. Thus, the use of dry sludge mortar and ash presented satisfactory results. Comparisons of energy consumption have shown that using sludge in mortars represents significant energy savings.
- Partial replacement of cement by sewage treatment plant sludge in eco-friendly cement mortarPublication . Martins, Ramiro; Pietrobelli, Juliana Martins Teixeira; Grabowski, Thais Theomaris dos SantosAiming to create alternatives for the disposal of sludge generated in wastewater treatment plants (WWTP) considering the circular economy principles and contributing to the reduction of environmental impacts generated by civil construction, the objective of this work was to evaluate the technical feasibility of the partial replacement of cement in the production of mortars by the sludge produced at the Bragança WWTP. The sludge was characterised, and different methods were used to prepare the sludge for the mortar. The sludge was incorporated by replacing part of the concrete mass of the mortar mixture. The specimens were tested for compressive strength. The specimen with 7% of sludge ash obtained the best result, the specimens with sludge from the drying-only treatments showed a result similar among themselves. The incorporation of the sludge resulted in mortars within the specification of the standard EN 998-1: 2018 and consequently have technical feasibility.
- Treatment and Valorisation of Pomace Olive Oil WastewaterPublication . Martins, Ramiro; Grabowski, Thais Theomaris dos SantosWastewater generated during the production of pomace olive oil is complex and highly variable due to different cultivation and processing characteristics. It has a high toxic organic load, low pH, and high chemical and biological demands. To reduce the concentration of chemical oxygen demand (COD) and total phenolic compounds (TPh) in pomace olive oil wastewater, several treatment processes have been studied. These include: (i) coagulation/flocculation, (ii) electrocoagulation, (iii) peroxy-electrocoagulation, (iv) electrochemical peroxidation, (v) Fenton, (vi) electro-Fenton, (vii) photo-Fenton, and (viii) adsorption. Coagulation/flocculation and electrocoagulation resulted in a maximum COD removal of 16%, while techniques involving the addition of hydrogen peroxide (iii-vii) had an average of 78% TPh removal but only 20% COD removal. Adsorption resulted in a maximum of 29% COD and 75% TPh removal. None of the tested techniques were able to remove more than 50% of COD, indicating the difficulty of removing organic matter in this effluent. However, advanced oxidation techniques were effective in degrading phenolic compounds, although they required relatively high dosages of oxidant.
- Treatment for the Olive Pomace Oil Extraction Industry by Appling Peroxy-ElectrooxidationPublication . Martins, Ramiro; Pinheiro, Luis Felipe do Nascimento; Grabowski, Thais Theomaris dos SantosThis study aimed to assess the effectiveness of peroxy-electrooxidation (PEO) for treating wastewater from the olive pomace oil extraction industry. The response surface methodology was utilized to optimize the efficiency of the PEO process under varying conditions of electrolysis time, current density, and hydrogen peroxide (H2O2) dosage. Appling graphite/aluminum sheets as cathode/anode in the treatment process showed that the concentration of H2O2 directly affected the efficiency of total phenolic compounds (TPh) removal. It was observed that at an H2O2 concentration of 15 g L-1, the removal efficiency was less than 80%. The removal of chemical oxygen demand (COD) is mainly influenced by the dosage of H2O2 and the reaction time. The experiments conducted on the PEO processes with graphite/iron sheets showed that the highest removal of TPh was achieved with an H2O2 dosage of 30 g L-1 and an intermediate reaction time of 30 minutes. Current density also had an impact on TPh removal. Regarding COD removal, the results showed that the highest removal rates were attained with increased H2O2 concentrations, but reaction time was a positive factor, with better results obtained with 30 and 50 minutes. The PEO is recommended as a pre-treatment for TPh removal but not for COD and other treatment processes should be evaluated.
- Treatment of Pomace Olive Oil Wastewater by Peroxy-Electrocoagulation with Aluminium SheetsPublication . Martins, Ramiro; Tesuka, Leticia Harumi; Grabowski, Thais Theomaris dos SantosThe extraction of olive pomace oil is a significant aspect of the edible oil industry in Mediterranean regions where olives are widely cultivated. The resulting wastewater generated from this industry is known to harbor pollutants, including residual solvents, oils, and chemicals from the refining process, that can have adverse effects on the environment and public health. Peroxy-electrocoagulation (PEC) is a method that can be used to treat wastewater from the olive pomace oil extraction industry. The purpose of the work was to reduce the concentration of pollutants in the effluent through the use of PEC with aluminum electrodes as a method of treatment. The Box-Behnken Design was used to study the relationship between hydrogen peroxide dosage (10, 20, and 30 g L-1), electric current density (5, 20 and 35 mA cm-2), and the initial pH (2.5, 3.5, and 4.5), in the PEC process, and the removal of chemical oxygen demand (COD) and total phenolic compounds (TPh). The highest removal was obtained with hydrogen peroxide dosage of 30 g L-1, and 20 mA cm-2, and with 29% of TPh removal at pH 2.5, and with 84% COD removal at pH 4.5. The procedure removed an average of 22% COD and 82% TPh. The concentration of hydrogen peroxide was one of the most significant factors in the process. Pre-treatment with other techniques is necessary to reduce harmful elements in the effluent before undergoing biological treatment.