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- Characterization and primary treatment of the effluent of olive pomace oil extractor industryPublication . Mazur, Andressa; Pietrobelli, Juliana Martins Teixeira; Martins, RamiroThe olive pomace oil is the principal by-product in the olive oil sector. Nonetheless the production uses olive bagasse after the primary extraction, it also produces by-products and effluents that need strategic approach to possibility reuse and a treatment. This study aimed for the characterization of the effluent from an olive pomace oil extractor industry and investigate the application of physicochemical pre-treatments to future water reuse. The physicochemical characterization shows high amounts of BOD and COD for the effluent freshly produced (E1) and effluent collected from storage tanks (E2) in the industrial plant. Other parameters were evaluated: Phosphorus, Organic nitrogen and Ammonia, FOG, Phenolic compounds, Alkalinity, TS, TDS and TSS, and Biodegradability (Zahn-Wellens Test). E2 shows the storage tanks were able to reduce 55% of TS and TDS, 77.5% of COD and 69% of BOD when compared with E1. Comparing with the Portuguese legislation, these effluents cannot be discharge to waterbodies and need treatments, such as coagulation and flocculation as tested in this work. Aluminium Sulphate show to work at best as a coagulant in the minimum concentration 10 g/L and pH 5, RIFLOC F45 (4 mg/L) was used as flocculant. After the treatment, it was observed a remotion of 95.6% of turbidity, 76,4% of COD,76,7% of TSS, and 85.4% of PhC when compared with E2. A sampling campaign was carried out on the Tua river to assess its water quality, and samples were taken at four different points to assess the impact of the effluent discharge, with none of the evaluated parameters presenting values higher than those recommended by the Law-Decree no236/98 from the Portuguese Legislation.
- Effluent characterization and waterbody monitoring from an olive pomace oil extractor industryPublication . Martins, Ramiro; Pietrobelli, Juliana Martins Teixeira; Mazur, AndressaThe environmental impact is a relevant aspect of the production of Olive oil, it is a relevant Portuguese economic sector, with job creation, maintaining rural populations, however the by-product, olive mill wastewater and olive pomace, became one important focus to the circular economy, one of the many valorizations economic viable is the olive pomace oil. The olive pomace oil industry is responsible for a secondary oil extraction based in mixture organic solvent with the olive pomace from the olive oil production. This process produces a wastewater what was physicochemical characterized -COD, BOD, TS, TSS, FOG, organic nitrogen, ammonia and phosphorus content, pH and conductivity, phenolic compounds and aromaticity, and Zahn-Wellens biodegradation test - in this study as the first step to a wastewater design for the factory. The main objective is to be able to return the treated wastewater in the river next to the factory with the required quality by the Portuguese legislation. The river water was also characterized in four different points to evaluate the factory environmental impact, the results show no large variation in the analyzed parameters when compared with the current legislation.)
- Uptake and release of zinc by aquatic bryophytes (Fontinalis antipyretica L. ex. Hedw.)Publication . Martins, Ramiro; Boaventura, RuiThe zinc uptake and posterior release by an aquatic bryophyte—Fontinalis antipyretica L. Ex Hedw.—was experimentally studied in laboratory exposing the plants to different zinc concentrations in the range, 1.0–5.0 mg l 1, for a 144 h contamination period, and then exposed to metal-free water for a 120 h decontamination period. The experiments were carried out in perfectly mixed contactors at controlled illumination, using mosses picked out in February 1997, with a background initial zinc concentration of 263mg g 1 (dry wt.). A first-order mass transfer kinetic model was fitted to the experimental data to determine the uptake and release constants, k1 and k2; the zinc concentration in mosses at the end of the uptake period, Cmu; and at the equilibrium, for the contamination and decontamination stages, Cme and Cmr; respectively. A bioconcentration factor, BCF ¼ k1=k2 (zinc concentration in the plant, dry wt./zinc concentration in the water) was determined. A biological elimination factor defined as BEF ¼ 1 Cmr=Cmu was also calculated. BCF decreases from about 4500 to 2950 as Zn concentration in water increases from 1.05 to 3.80mg l 1. BEF is approximately constant and equal to 0.80. Comparing Zn and Cu accumulation by Fontinalis antipyretica, it was concluded that the uptake rate for Zn (145 h 1) is much lower than for Cu (628 h 1) and the amount retained by the plant decreased by a factor of about seven.
- Multistage treatment for olive mill wastewater: Assessing legal compliance and operational costsPublication . Vuppala, Srikanth; Paulista, Larissa Oliveira; Morais, Daniela F.S.; Pinho, Inês L.; Martins, Ramiro; Gomes, Ana I.; Moreira, Francisca C.; Vilar, Vítor J.P.A treatment train for the remediation of a raw olive mill wastewater (OMW) was investigated, aiming to comply with the emission limit values (ELVs) for direct discharge into water bodies. The following stages were proposed: (i) pre-treatment (filtration and sedimentation), (ii) coagulation, (iii) biological oxidation, and (iv) advanced oxidation process (AOP). Under the best-operating conditions for coagulation (0.8 g L- 1 of Al2(SO4)3, pH = 4.5), high removal of total suspended solids (TSS) (97%), turbidity (98%), and phenols (57%) was achieved, along with a decrease in the inhibition of the biological activity. A subsequent biological oxidation stage provided a high removal of organic matter (chemical oxygen demand (COD) removal of 73%). For the third stage, three AOPs were applied and compared – photo-Fenton with UVA radiation (PF-UVA), anodic oxidation (AO), and ozonation (O3). After 3 h of treatment, the PF-UVA process (pH = 2.8, [H2O2] = 400–500 mg L- 1, [Total dissolved iron]0 = 100 mg L- 1) allowed to meet the ELV for COD, but the other parameters exceeded the threshold, while O3 process (inlet concentration = 100 mg O3 Ndm- 3, gas flow = 0.2 Ndm3 min- 1) allowed to comply with phenols, TSS, and sulfate limits. The AO process (current density up to 200 mA cm- 2) was the least efficient AOP for all studied parameters. The operational costs for the coagulation and biological oxidation stages were estimated at 1.20 € m- 3. Regarding the most effective AOPs, ozonation presented an estimated cost 2.3-fold higher than PF-UVA (11.9 € m- 3 vs. 5.2 € m- 3).
- Environmental factors and reactor configurations in biogas production from anaerobic co-digestion of fruit wastesPublication . Kreutz, Cristiane; Carvalho, Karina Querne de; Martins, RamiroA search for alternatives economically viable and environmentally sound to the world energy demand, stimulated the research in the field of anaerobic digestion, as a form of renewable energy and the anaerobic co-digestion is an alternative to use different types of residues, including food wastes. Therefore, this article presents an analysis of the scientific advances realized of the period of 2015 to 2018 in terms of anaerobic co-digestion, with emphasis on the use of different food residues, especially fruit and vegetable wastes, a different configuration of reactors, and kind of operational conditions used. A description of environmental factors affecting the process efficiency and the biogas generation based on substrate characteristics is presented in this review since these factors play an important role in the biogas yield and determine the metabolic conditions of the microorganism growth. Therefore, research should focus on the anaerobic digestion process balance, to identify optimal operating conditions through the use and valorization of wastes.
- Acumulação e libertação de metais pesados por briófitas aquáticasPublication . Martins, RamiroTradicionalmente a remoção de metais pesados de efluentes é feita usando diversas técnicas (precipitação, electrólise, permuta iónica, osmose inversa, adsorção), normalmente dispendiosas e/ou pouco eficientes para soluções diluídas. A biossorção, processo em que materiais naturais ou seus derivados são usados na remoção e recuperação de metais pesados, proporciona um tratamento alternativo competitivo, pelo que os respectivos parâmetros cinéticos e de equilíbrio devem ser bem conhecidos, de modo a prevenir fracassos na sua aplicação. Nesse contexto, este trabalho teve por objectivo estudar os processos de bioacumulação/eliminação e de biossorção de Cd(II), Cr(VI), Pb(II) e Zn(II) pelo musgo aquático Fontinalis antipyretica, espécie largamente dispersa nos lagos e rios Portugueses. Os musgos aquáticos são capazes de acumular iões metálicos em solução aquosa e de libertá-los parcialmente quando expostos em água isenta de metal. Desempenham um papel importante na avaliação e na remoção de elementos tóxicos na água. A vantagem dos musgos relativamente a uma amostragem directa da água é que o seu uso permite uma integração de variações no espaço e no tempo, favorece o nível de quantificação do contaminante por concentração dos elementos tóxicos e fornece informação acerca das espécies biodisponíveis. Foram realizadas treze experiências laboratoriais em contínuo para determinar as cinéticas de acumulação e libertação de metal pelo musgo. Um modelo cinético de transferência de massa de primeira ordem (modelo de dois compartimentos) foi ajustado aos resultados experimentais, para determinar as constantes de acumulação e de eliminação, k1 e k2, a concentração de metal nos musgos no fim do período de acumulação, Cmu, e no equilíbrio, para as fases de contaminação e descontaminação, Cme e Cmr, respectivamente. Foram determinados factores de bioconcentração, BCF = k1 / k2, e de eliminação biológica, BEF = 1 - Cmr / Cmu. Para avaliação dos mecanismos envolvidos no processo de acumulação global dos metais foram estudados o efeito da concentração do metal, do pH do meio, da temperatura, da intensidade luminosa, do estado fisiológico da biomassa (época de colheita), da natureza da biomassa (viva/morta), da dureza da água e da realização de ciclos de contaminação/descontaminação consecutivos. Foram ainda realizadas experiências cinéticas e de equilíbrio em adsorvedor fechado, para avaliar o potencial do musgo como biossorvente de metais pesados em futuras aplicações industriais. Numa avaliação preliminar deste tipo de biossorvente, foi estudada a influência de alguns parâmetros operacionais, como o tempo de contacto, a concentração inicial de metal, a concentração de musgo usada e a presença de outros iões metálicos, na cinética de acumulação de Cd(II), Cr(VI), Pb(II) e Zn(II). Ajustaram-se diferentes modelos cinéticos – Lagergren, pseudo-segunda ordem, segunda ordem modificado de Ritchie, de Elovich e Sorção Dinâmica – aos resultados experimentais obtidos em adsorvedor fechado. O modelo de pseudo-segunda ordem foi o que conduziu ao melhor ajuste. Nos ensaios de equilíbrio em sistema fechado foi avaliada a influência da concentração inicial de ião metálico, pH inicial, temperatura, dureza da água e natureza do sal de metal usado no processo de biossorção. Ajustaram-se quatro modelos de equilíbrio – Langmuir, Freundlich, Redlich-Peterson e Langmuir-Freundlich – aos resultados experimentais tendo-se obtido parâmetros estatisticamente significativos para os modelos de Langmuir e Freundlich. Para um nível de confiança de 95% qualquer dos dois modelos descreve adequadamente os resultados experimentais. A eliminação de metais pesados em solução aquosa por biossorção em musgos aquáticos revelou-se um processo interessante, podendo ser aplicado na purificação de águas residuais industriais contendo metais. A capacidade máxima de biossorção de qualquer um dos iões metálicos é elevada, apresentando valores da mesma ordem de grandeza ou mesmo superiores aos obtidos com outros biossorventes.
- 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.
- 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.
- Correlation analysis for screening key parameters for fish canning wastewater characterizationPublication . Cristovão, Raquel; Martins, Ramiro; Loureiro, José M.; Boaventura, RuiA significant number of food industries do not have a proper wastewater treatment; fish canning is no exception, and the existing pre-treatment is insufficient, given the content of organic matter, oil and grease and salinity. In addition, this type of wastewaters shows high variability depending on the type of processes involved and effluent streams being discharged [1]. For this reason, its characterization is very important to conceive and implement the correct wastewater treatment layout. In this work, correlation analysis was used to identify the relationship between each wastewater parameter analyzed. Correlation coefficients between each parameter reflect their importance compared to others.
- Interactive/automated method to count bacterial coloniesPublication . Monteiro, Fernando C.; Ribeiro, J.E.; Martins, RamiroThe number of colonies in a culture is counted to calculate the concentration of bacteria in the original broth; however, manual counting can be tedious, time-consuming and imprecise. Automation of colony counting has been of increasing interest for many decades, and these methods have been shown to be more consistent than manual counting. Significant limitations of many algorithms used in automated systems are their inability to recognize overlapping colonies as distinct and to count colonies on the plate boundary. This study proposes an interactive semi-automated counting system and a fully automated counting system using image processing methods which overcomes these problems. The proposed systems are capable to reduce the manpower and time required for counting colonies while taking account colonies both around the central area and boundary areas of a Petri dish.