Optimizing ozone treatment for pathogen removal and disinfection by-product control for potable reuse at pilot-scale.

Reclaimed water poses environmental and human health risks due to residual organic micropollutants and pathogens. Ozonation of reclaimed water to control pathogens and trace organics is an important step in advanced water treatment systems for potable reuse of reclaimed water. Ensuring efficient pathogen reduction while controlling disinfection byproducts remains a significant challenge to implementing ozonation in reclaimed water reuse applications. This study aimed to investigate ozonation conditions using a plug flow reactor (PFR) to achieve effective pathogen removal/inactivation while minimizing bromate and N-Nitrosodimethylamine (NDMA) formation. The pilot scale study was conducted using three doses of ozone (0.7, 1.0 and 1.4 ozone/total organic carbon (O3/TOC) ratio) to determine the disinfection performance using actual reclaimed water. The disinfection efficiency was assessed by measuring total coliforms, Escherichia coli (E. coli), Pepper Mild Mottle Virus (PMMoV), Tomato Brown Rugose Fruit Virus (ToBRFV) and Norovirus (HNoV). The ozone CT values ranged from 1.60 to 13.62 mg min L-1, resulting in significant reductions in pathogens and indicators. Specifically, ozone treatment led to concentration reductions of 2.46-2.89, 2.03-2.18, 0.46-1.63, 2.23-2.64 and > 4 log for total coliforms, E. coli, PMMoV, ToBRFV, and HNoV, respectively. After ozonation, concentrations of bromate and NDMA increased, reaching levels between 2.8 and 12.0 µg L-1, and 28-40.0 ng L-1, respectively, for average feed water bromide levels of 86.7 ± 1.8 µg L-1 and TOC levels of 7.2 ± 0.1 mg L-1. The increases in DBP formation were pronounced with higher ozone dosages, possibly requiring removal/control in subsequent treatment steps in some potable reuse applications.

A pilot-scale study of a novel system for simultaneous nitrogen and carbon removal: technological advancement of a structured bed reactor with intermittent aeration (SBRIA) in real domestic sewage treatment.

This study outlines the development of an effective pilot-scale simultaneous denitrification and nitrification (SDN) system using intermittent aeration for the removal of carbon and nitrogen from real domestic sewage. Given the limited research in this area, the main objective was to evaluate the overall performance of the SBRIA system on a pilot scale and show its benefits in domestic wastewater treatment. The structured bed reactor with intermittent aeration (SBRIA) notably achieved 57% efficiency in removing total nitrogen without requiring external carbon sources. It also demonstrated impressive removal rates of 56% for total chemical oxygen demand (CODT) and 82% for biochemical oxygen demand (BOD5), indicating its effectiveness in degrading organic matter. In addition, the SBRIA showed high pH control and managed the consumption of alkalinity without the need for an alkalizer, maintaining consistent mean values of 7.7 ± 0.8 for pH and 166.8 ± 79.8 mg·L-1 for alkalinity. The system also proved resilient against toxic shocks caused by significant variations in influent characteristics. This study offers valuable insights and compelling results into a cost-effective and efficient treatment approach using an innovative technology not previously applied at the pilot scale. Its potential to remediate polluted water is substantial.

Biodegradation of pesticide-contaminated wastewaters from a formulation plant employing a pilot scale biobed.

In this work, a pilot biobed was built up to treat pesticide-contaminated wastewaters discharged from a formulation plant. The pre-treated wastewater was spiked with additional pesticides in order to simulate a scenario of higher contamination: glyphosate, atrazine, imidacloprid, prometryn and carbendazim were added to reach a final Total Organic Carbon (TOC) concentration of 70 mg L-1. An Intermediate Bulk Container (IBC) was filled with a biomixture of soil and foxtail millet stubble (50:50% v v-1), and 200 l of the wastewater was added to the system recycling tank. The recirculation to the IBC was established for 12 h. After that (Day 0), the recirculation was turned on during the assay only to maintain the moisture for 180 days. Biomixture and wastewater samples were taken periodically to analyse pesticides and phytotoxicity in both matrices. In addition, hydrolytic and phenoloxidase activities, total bacteria and yeast and fungi communities were determined in the biomixture. The designed pilot scale biobed allowed to treat wastewaters with high concentration of pesticides reaching a complete removal of glyphosate, AMPA, atrazine, carbendazim and prometryn at 180 days. A good degradation percentage of the recalcitrant imidacloprid was achieved (60%) and the biomixture showed enough biological activity to continue treating additional wastewater. The root elongation index from the germination test showed low toxicity on day 180 both in biomixture and wastewater. The millet stubble resulted an appropriate lignocellulosic material to be used in biobeds to treat a wide variety of pesticides. The application of the seed germination test proved to be a low cost and simple tool to determine the end point of the process.

Upgrading from batch to continuous flow process for the pyrolysis of sugarcane bagasse: Structural characterization of the biochars produced.

The waste from agriculture can be used for biochar production by the pyrolysis process. The present work aimed was to produce sugarcane bagasse biochars using different temperatures and processes (batch and pilot-scale continuous flow). The samples were characterized by FTIR, functional group pKa, elemental analysis, zeta potential, Raman spectroscopy, EPR, and SEM. The FTIR spectra showed bands around 1400-1650 cm-1 corresponded to vibrations of CC bonds and pKa revealed the presence of carboxylic acids (pKa ≤5) and lactones (pKa ~5-9). The elemental analyses (H/C ~ 0.31) and Raman spectra (ID/IG ~ 0.55) confirmed greater carbonization and less structural disorder of the material produced using the continuous flow process. SEM images showed that the biochar morphologies were similar to that of the precursor biomass, with the formation of pores. The continuous flow process is a promising technique for the production of biochars with high carbon contents and aromatic structures, as well as lower defect degrees, compared to biochars produced using a batch process.

Production of zeolitic materials in pilot scale based on coal ash for phosphate and potassium adsorption in order to obtain fertilizer.

The use of different types of zeolites (X, Na-P1, and 4A) synthesized by different methods and scales were tested in this work to adsorb nutrients present in synthetic solutions and industrial effluents for later application as fertilizer. Modifications with calcium chloride were performed on the zeolite with the best performance to increase its adsorption capacity. The best performing zeolite was type X (ZXH) produced on a pilot scale by the hydrothermal process. Its adsorption capacity without modification was 149 mg P-PO4/g zeolite and 349 mg K/g zeolite. With the change, there was a fourfold increase in these results, which were up to threefold higher than reported in the literature. The kinetic model that best characterized the adsorption process was the intraparticle diffusion model, and the equilibrium isotherm was that of Freundlich. The adsorption tests performed with industrial effluent showed high removal of the nutrients of interest (> 90% for PO43- and > 95% for K+). The desorption tests with zeolites nutrient-loaded from synthetic solutions showed 13 to 24% PO43- and 14 to 47% K+ release within 24 h, while for zeolite nutrient-loaded from effluent the release were 7 and 100% for PO43- and K+, respectively. The results we obtained in this work indicated the potential use of zeolites in the treatment of effluent and its application as a fertilizer.

Cell separation of Haemophilus influenzae type b through tangential microfiltration

Centrifugation techniques are frequently used to separate bacteria from the culture broth in pharmaceutical industries. Alternatively, cell separation can be performed through tangential microfiltration systems; an arguably cost-effective alternative to centrifugation. Therefore, replacement of centrifugation steps with microfiltration represents an attractive option in order to decrease production costs. An example of such use can be found in the production of the vaccine against Haemophilus influenzae type b (Hib), which relies on a centrifugation step to separate the pathogenic bacteria from the antigen-rich (exopolysaccharide) released into culture broth. The substitution of the centrifugation operation with tangential microfiltration may decrease production costs and increase vaccine availability in low-income regions. Hence, we studied the impact of diverse microfiltration systems at different production scales in the separation of Hib from its culture broth. The recovery of the exopolysaccharide - polyribosylribitol phosphate (PRP), the antigen employed in the vaccine, produced by Hib and present in the culture broth was used as a read-out for process efficiency. In sum, the use of Hydrophilic Polyvinylidene Fluoride (PVDF) membranes resulted in the highest recovery value among the tested materials; moreover, the transmembrane pressure was a paramount factor determining the recovery level. We concluded that Hib cell separation through tangential microfiltration systems represents a feasible alternative to centrifugation.

Impact of chemical modifications in pilot-scale isolated sorghum starch and commercial cassava starch.

The aim of this work was to evaluate the impact of different chemical modification methods on starch from different botanical sources. Brown and white sorghum starch was isolated throughout a time saving process and avoiding the use of dangerous compounds. Brown and white sorghum and commercial cassava starch were treated using acetic acid, acetic anhydride and octanoyl chloride. Its chemical, morphological and thermal characterization was afterwards carried out. The modifications reduced amylose content and increased damaged starch. Both acetylation and acid treatment produced no significant changes in the size and shape of granules; yet, they increased superficial pores. SEM observations supported the results, indicating that octanoyl modification causes a partial destruction of the granule structure. Thus, particle size distribution changes significantly. Crystallinity degree decreased with all the modifications. However, the effect was more pronounced in octanoyl esterification. In general, modifications increase the water absorption of the native starch but no considerable effect was found over oil absorption, and gelatinization parameters were significantly altered as a result of modifications. Starch from these subtilized sources was successfully modified, which could arouse interest in its industrial production.

Effectiveness of vertical subsurface wetlands for iron and manganese removal from wastewater in drinking water treatment plants / Eficacia de humedales subsuperficiales verticales en la remoción de hierro y manganeso de aguas residuales de plantas potabilizadoras / Eficácia das zonas úmidas subsuperficiais verticais na remoção de ferro e manganês das águas residuais de estações de tratamento de água potável

Abstract Population growth and urbanization pose a greater pressure for the treatment of drinking water. Additionally, different treatment units, such as decanters and filters, accumulate high concentrations of iron (Fe) and manganese (Mn), which in many cases can be discharged into the environment without any treatment when maintenance is performed. Therefore, this paper evaluates the effectiveness of vertical subsurface wetlands for Fe and Mn removal from wastewater in drinking water treatment plants, taking a pilot scale wetland with an ascending gravel bed with two types of plants: C. esculenta and P. australis in El Hormiguero (Cali, Colombia), as an example. The pilot system had three upstream vertical wetlands, two of them planted and the third one without a plant used as a control. The wetlands were arranged in parallel and each formed by three gravel beds of different diameter. The results showed no significant difference for the percentage of removal in the three wetlands for turbidity (98 %), Fe (90 %), dissolved Fe (97 %) and Mn (98 %). The dissolved oxygen presented a significant difference between the planted wetlands and the control. C. esculenta had the highest concentration of Fe in the root with (103.5 ± 20.8) μg/g; while P australis had the highest average of Fe concentrations in leaves and stem with (45.7 ± 24) μg/g and (41.4 ± 9.1) μg/g, respectively. It is concluded that subsurface wetlands can be an interesting alternative for wastewater treatment in the maintenance of drinking water treatment plants. However, more research is needed for the use of vegetation or some technologies for the removal or reduction of the pollutant load in wetlands, since each drinking water treatment plant will require a treatment system for wastewater, which in turn requires a wastewater treatment system as well

Resumen El crecimiento de la población y la urbanización imponen una mayor presión al tratamiento de agua potable. Por otra parte, las diferentes unidades de tratamiento, como decantadores y filtros, acumulan altas concentraciones de hierro (Fe) y manganeso (Mn), las cuales, en muchos casos, son descargadas en el ambiente sin ningún tratamiento cuando se hace mantenimiento. Este artículo evalúa la efectividad de humedales subsuperficiales de flujo vertical para la remoción de Fe y Mn provenientes de agua residual en plantas de tratamiento de agua potable, tomando como ejemplo un humedal de flujo ascendente a escala piloto, con un lecho de grava y dos tipos de plantas: C. esculenta y P. australis en El Hormiguero (Cali, Colombia). El sistema piloto consistió en tres humedales verticales de flujo ascendente, dos de ellos plantados y el tercero sin plantas, como control. Los humedales se organizaron en paralelo, cada uno formado por tres lechos de grava de diferente diámetro. Los resultados mostraron que no hubo diferencia significativa en el porcentaje de remoción en los tres humedales para turbidez (98 %), Fe (90 %), Fe disuelto (97 %) y Mn (98 %). El oxígeno disuelto presentó una diferencia significativa entre los humedales plantados y el control. C. esculenta tuvo la concentración más alta de Fe en la raíz, con (103.5 ± 20.8) μg/g; mientras que P. australis tuvo el promedio más alto de concentraciones de Fe en hojas y tallos, con (45.7 ± 24) μg/g y (41.4 ± 9.1) μg/g, respectivamente. Se concluye que los humedales subsuperficiales pueden ser una alternativa interesante para el tratamiento de aguas residuales en el mantenimiento de plantas de tratamiento de agua potable. Sin embargo, se requiere más investigación sobre el uso de vegetación u otras tecnologías para la remoción o reducción de la carga contaminante en humedales, ya que cada planta de tratamiento de agua potable o su sistema de tratamiento de aguas residuales con humedales mantendrá el contaminante en el sistema.

Resumo O crescimento da população e da urbanização impõem uma maior pressão ao tratamento de água potável. Adicionalmente, as diferentes unidades de tratamento, como decantadores e filtros, acumulam altas concentrações de ferro (Fe) e manganês (Mn), as quais, em muitos casos, são liberadas no ambiente durante a manutenção, sem receber nenhum tipo de tratamento. Este artigo avaliou a eficácia de zonas úmidas subsuperficiais de fluxo vertical na remoção de Fe e Mn provenientes das águas residuais de estações de tratamento de água potável, usando como exemplo uma zona úmida a escala piloto com fluxo ascendente, leito de cascalho e dois tipos de plantas, C. esculenta e P. australis, localizada em El Hormiguero (Cali, Colombia). O sistema piloto usou três zonas úmidas verticais de fluxo ascendente, duas delas com plantas e a terceira sem plantas, como controle. As zonas húmidas foram organizadas em paralelo, cada uma sendo formada por três leitos de cascalho de diferente diâmetro. Os resultados mostraram que não houve diferença significativa na porcentagem de remoção das três zonas úmidas em termos de turbidez (98 %), Fe (90 %), Fe dissolvido (97 %) e Mn (98 %). O oxigênio dissolvido apresentou uma diferença significativa entre as zonas úmidas plantadas e a controle. C. esculenta teve a concentração mais alta de Fe na raiz, (103.5 ± 20.8) μg/g, em quanto P. au tralis teve a maior média de concentrações de Fe nas folhas e nos talos, (45.7 ± 24) μg/g e (41.4 ± 9.1) μg/g, respetivamente. Concluiuse que as zonas úmidas subsuperficiais podem ser uma alternativa interessante para o tratamento de águas residuais durante a manutenção de estações de tratamento de água potável. No entanto, mais pesquisa é necessária para determinar a importâncias do uso da vegetação ou outras tecnologias para a remoção ou diminuição da carga contaminante nas zonas úmidas, pois cada estação de tratamento de água potável ou sistema de tratamento de águas residuais com zonas úmidas irá manter oconaminante no sistema.

Microencapsulated food-grade antioxidant applied as a preservative of peanut seed quality in microcosm- and pilot-scale trials.

BACKGROUND: In Argentina, peanuts are stored for 3-6 months. It is important to avoid proliferation of fungi and insect pests during this period. In this study, the potential of butylated hydroxyanisole (BHA) microcapsules to conserve peanut kernels was evaluated in microcosms and on a pilot scale. RESULTS: In microcosm assays, microcapsules containing BHA at a dose of 1802 µg g-1 reduced 37% of total fungal count. Higher reductions (77-100%) were obtained with a combined treatment with BHA formulation (1802 µg g-1 ) plus fungicide (methyl thiophanate 0.0100 g L-1  and metalaxyl 0.0133 g L-1 ). However, germination levels of peanut seeds treated with the BHA formulation were less than 6% throughout the incubation time. In pilot-scale trials, the storage conditions allowed the control of fungal development and insect proliferation. Quantifiable levels of BHA were also detected throughout the entire storage period. The combined treatment significantly reduced fungal contamination at 2 months of storage (C1-2015: 37.41%; C1-2016: 28.48%; C2-2016: 45.02%). Seed germination of unshelled stored peanuts was not affected by the formulation. CONCLUSION: The application of the BHA formulation during storage combined with pre-seeding treatment could be an appropriate strategy to maintain the quality of the peanut kernels destined for seed. © 2018 Society of Chemical Industry.

Drying of microalga Scenedesmus obliquus BR003 in a gas dryer at low temperatures / Secagem da microalga Scenedesmus obliquus BR003 em secador a gás em baixas temperaturas

RESUMO: O desenvolvimento de equipamentos eficientes e específicos para a secagem de microalgas é essencial para a exploração comercial destes microrganismos que apresentam alta taxa de crescimento e grande potencial biotecnológico. Os custos de secagem da biomassa de microalgas ainda são elevados e precisam ser reduzidos para a produção de compostos com baixo valor agregado. Portanto, realizou-se o estudo da secagem da microalga Scenedesmus obliquus BR003 utilizando baixas temperaturas. S. obliquus BR003 é uma microalga robusta que apresenta alta produtividade de lipídeos. Em escala laboratorial, observou-se que a biomassa de S. obliquus BR003 foi rapidamente seca em baixas temperaturas entre 50 e 60 ºC. Um secador a gás foi utilizado para avaliar a secagem da biomassa de S. obliquus BR003 em escala piloto. A biomassa foi seca em menos de 24 h utilizando o secador a gás, entretanto, a elevada umidade da biomassa da microalga requereu uma maior renovação de ar na câmara do secador. A análise de fluidodinâmica computacional do secador a gás mostrou dois parâmetros importantes para se obter uma maior efetividade de transferência de calor e massa durante o processo de secagem da biomassa de microalga. Concluiu-se que um secador a gás adequado, para a biomassa de microalgas, deve possuir múltiplos pontos de injeção de ar, e um eficiente sistema de circulação e renovação de ar no interior da câmara de secagem.

ABSTRACT: Development of efficient and specific equipment to dry microalgae is essential for commercial use of these microorganisms that show high growth rates and biotechnological potential. Drying costs of microalgae biomass are still high and they should be reduced for the production of compounds with low added value. Therefore, we evaluated the drying process of the microalga Scenedesmus obliquus BR003 using low temperatures. S. obliquus BR003 is a robust microalga that shows high lipid productivity. At laboratory scale, it was observed that the biomass of S. obliquus BR003 was rapidly dried at low temperatures between 50 and 60 ° C. A gas dryer was used to evaluate the drying of the biomass of S. obliquus BR003 on a pilot-scale. The biomass was dried in less than 24 h using the gas dryer; however, the high moisture of the microalga biomass required a higher air renovation in the drying chamber. Computational fluid dynamics analysis of the gas dryer showed two important parameters to achieve greater effectiveness of heat and mass transfer rates during the drying process of the microalga biomass. It was concluded that a gas dryer suitable for the microalgae biomass should have multiple air injection points, and an efficient circulation and renovation system of air inside the drying chamber.

Drying of microalga Scenedesmus obliquus BR003 in a gas dryer at low temperatures / Secagem da microalga Scenedesmus obliquus BR003 em secador a gás em baixas temperaturas

O desenvolvimento de equipamentos eficientes e específicos para a secagem de microalgas é essencial para a exploração comercial destes microrganismos que apresentam alta taxa de crescimento e grande potencial biotecnológico. Os custos de secagem da biomassa de microalgas ainda são elevados e precisam ser reduzidos para a produção de compostos com baixo valor agregado. Portanto, realizou-se o estudo da secagem da microalga Scenedesmus obliquus BR003 utilizando baixas temperaturas. S. obliquus BR003 é uma microalga robusta que apresenta alta produtividade de lipídeos. Em escala laboratorial, observou-se que a biomassa de S. obliquus BR003 foi rapidamente seca em baixas temperaturas entre 50 e 60 ºC. Um secador a gás foi utilizado para avaliar a secagem da biomassa de S. obliquus BR003 em escala piloto. A biomassa foi seca em menos de 24 h utilizando o secador a gás, entretanto, a elevada umidade da biomassa da microalga requereu uma maior renovação de ar na câmara do secador. A análise de fluidodinâmica computacional do secador a gás mostrou dois parâmetros importantes para se obter uma maior efetividade de transferência de calor e massa durante o processo de secagem da biomassa de microalga. Concluiu-se que um secador a gás adequado, para a biomassa de microalgas, deve possuir múltiplos pontos de injeção de ar, e um eficiente sistema de circulação e renovação de ar no interior da câmara de secagem.(AU)

Development of efficient and specific equipment to dry microalgae is essential for commercial use of these microorganisms that show high growth rates and biotechnological potential. Drying costs of microalgae biomass are still high and they should be reduced for the production of compounds with low added value. Therefore, we evaluated the drying process of the microalga Scenedesmus obliquus BR003 using low temperatures. S. obliquus BR003 is a robust microalga that shows high lipid productivity. At laboratory scale, it was observed that the biomass of S. obliquus BR003 was rapidly dried at low temperatures between 50 and 60 ° C. A gas dryer was used to evaluate the drying of the biomass of S. obliquus BR003 on a pilot-scale. The biomass was dried in less than 24 h using the gas dryer; however, the high moisture of the microalga biomass required a higher air renovation in the drying chamber. Computational fluid dynamics analysis of the gas dryer showed two important parameters to achieve greater effectiveness of heat and mass transfer rates during the drying process of the microalga biomass. It was concluded that a gas dryer suitable for the microalgae biomass should have multiple air injection points, and an efficient circulation and renovation system of air inside the drying chamber.(AU)

Design and testing of a pilot scale magnetic separator for the treatment of textile dyeing wastewater.

Iron nanoparticles can be incorporated on the structure of natural clays to obtain magnetic clays, an adsorbent that be easily removed from a wastewater by magnetic means. Magnetic clays have high adsorption capacities of different contaminants such as heavy metals, fungicides, aromatic compounds and colorants and show rapid adsorption kinetics, but crucial data for achieving its full or pilot scale application is still lacking. In this work, magnetic bentonites with different amounts of magnetite (iron fractions on the clay of 0.55, 0.6 and 0.6) were used to remove color from a real textile wastewater. On a first stage the optimal conditions for the adsorption of the dye, including pH, temperature and clay dosage were determined. Also design parameters for the separation process such as residence time, distance from magnet to magnetic clay and magnet strength were obtained. Finally a pilot scale magnetic drum separator was constructed and tested. A removal of 60% of the dye from a wastewater that contained more than 250 ppm of azo dye was achieved with only 10 min of residence time inside the separator.

Removal of mercury from gold mine effluents using Limnocharis flava in constructed wetlands.

Phytoremediation has received increased attention over the recent decades, as an emerging and eco-friendly approach that utilizes the natural properties of plants to remediate contaminated water, soils or sediments. The current study provides information about a pilot-scale experiment designed to evaluate the potential of the anchored aquatic plant Limnocharis flava for phytoremediation of water contaminated with mercury (Hg), in a constructed wetland (CW) with horizontal subsurface flow (HSSF). Mine effluent used in this experiment was collected from a gold mining area located at the Alacran mine in Colombia (Hg: 0.11 ± 0.03 µg mL-1) and spiked with HgNO3 (1.50 ± 0.09 µg mL-1). Over a 30 day test period, the efficiency of the reduction in the heavy metal concentration in the wetlands, and the relative metal sorption by the L. flava, varied according to the exposure time. The continued rate of removal of Hg from the constructed wetland was 9 times higher than the control, demonstrating a better performance and nearly 90% reduction in Hg concentrations in the contaminated water in the presence of L. flava. The results in this present study show the great potential of the aquatic macrophyte L. flava for phytoremediation of Hg from gold mining effluents in constructed wetlands.

Microbial community in a pilot-scale bioreactor promoting anaerobic digestion and sulfur-driven denitrification for domestic sewage treatment.

A pilot-scale reactor treating domestic sewage was operated to promote anaerobic digestion and denitrification using endogenous electron donors. While 55 % of organic matter was removed, nitrogen and sulfur showed a different dynamics during the operation. Pyrosequencing analysis clarified this behavior revealing that specific microbial communities inhabited the anaerobic (47.05 % of OTUs) and anoxic (31.39 % of OTUs) chambers. Analysis of 16S rRNA gene partial sequences obtained through pyrosequencing revealed a total of 1727 OTUs clustered at a 3 % distance cutoff. In the anaerobic chamber, microbial community was comprised of fermentative, syntrophic and sulfate-reducing bacteria. The majority of sequences were related to Aminobacterium and Syntrophorhabdus. In the anoxic chamber, the majority of sequences were related to mixotrophic and strictly autotrophic denitrifiers Arcobacter and Sulfuricurvum, respectively, both involved in sulfur-driven denitrification. These results show that pyrosequencing was a powerful tool to investigate the microbial panorama of a complex system, providing new insights to the improvement of the system.