Consistency between the metabolic performance of two aerobic granular sludge systems and the functional groups of bacteria detected by amplicon sequencing.

Two sequential batch reactors (R1 and R2) of aerobic granular sludge (AGS) were inoculated with activated sludge of different origins. The objective was to investigate the granulation and the consistency between the structure of the microbial communities (16S rRNA amplicon sequencing) in each reactor and their metabolic performance (removal of C, N, and P). Both reactors were fed with acetate-based synthetic wastewater, targeting an anaerobic-aerobic cycle reputed to favor the phosphorus- and glycogen-accumulating organisms (PAO and GAO). Stable granulation was achieved in both reactors, where, instead of PAO, the dominant genera were ordinary heterotrophic organisms (OHO) such as Thauera, Paracoccus, and Flavobacterium known for their high capacity of aerobic storage of polyhydroxyalkanoates (PHA). Generally, there was good consistency between the metabolic behavior of each reactor and the bacterial genera detected. Both reactors showed high removals of C and complete nitrification (Nitrosomonas and Nitrospira detected) but a low level of simultaneous nitrification-denitrification (SND) during the aerated phase. The latter causes that nitrates were recycled to the initial phase, in detriment of PAO selection. Meanwhile, the study showed that selecting slow-growing OHOs (with aerobic storage capacity) favors stable granulation, revealing an alternative AGS technology for C and N removal.

Municipal Wastewater Treatment Plants: Gap, Challenges, and Opportunities in Environmental Management.

Municipal Wastewater Treatment Plants (MWWTPs) have proven to be sources of adverse environmental impacts; however, integrated management can help improve their efficiency. Therefore, this study aims to evaluate the gap between the current management and another based on an international standard applied to WWTPMs, in order to understand their environmental commitment, and to identify the challenges and opportunities they present for the adoption or certification of an environmental management system (EMS) based on ISO 14001. For this purpose, a descriptive cross-sectional study was carried out in two MWWTPs in southern Mexico. In a first step, an automated checklist was designed based on the requirements of the ISO 14001:2015 standard and based on a modified FMEA (Failure Mode and Effects Analysis) calculation method. In a second step, a diagnosis was carried out at the MWWTPs, followed by a SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis to determine internal and external factors until a series of challenges and opportunities was identified. The findings indicate that the selected MWWTPs have a wide gap that keeps them away from efficient management. Among the challenges, "limited financial resources" were identified followed by "high turnover of managerial staff", while the opportunities with the greatest potential for improvement are related to the factors "candidate for investment" and "environmental policy". The treatment plants show a weak environmental commitment, therefore rigorous action plans should be considered, not only to protect the environment but also the investment, and they should be the main promoters that challenge the private sector.

Extraction and clean-up methods for organochlorine pesticides determination in milk.

Organochlorine pesticides (OCPs) can cause environmental damage and human health risks since they are lipophilic compounds with high resistance to degradation and long half-lives in humans. As most persistent OCPs have been banned years ago, it is expected to find these compounds at trace levels in environment. Therefore, increasingly sensitive and reliable analytical techniques are required to ensure effective monitoring of these compounds. The aim of this review is to discuss extraction and clean-up methods used to monitor OCP residues in milk, reported in the last 20 years. To carry out this review, an exhaustive bibliographic review was conducted. Despite the disadvantages of conventional extraction and clean-up methods, such as liquid-liquid, solid-phase or Soxhlet extractions, these procedures are still used due to their reliability. New extraction methods, like solid-phase microextraction, matrix solid-phase dispersion or QuEChERS, have not been thoroughly evaluated for OCP determination in milk. Almost all the methodologies analyzed in this review presented good performance characteristics according to the performance acceptability criteria set in SANCO's procedure. Comparison between limits of quantification (LOQ) and detection (LOD), for the reported methodologies, is not always possible due to the heterogeneity of the units. Thus, researchers should take into account an homogenization of LOD and LOQ units, according to the international regulations and MRLs established. Finally, more research is necessary to obtain the ideal methodology for OCPs determination in milk, which comprises the environmentally friendly characteristics of the new techniques and the reliability of the traditional methodologies.

Diclofenac-induced oxidative stress in brain, liver, gill and blood of common carp (Cyprinus carpio).

Due to its analgesic properties, diclofenac (DCF) is one of the most commonly used non-steroidal anti-inflammatory drugs (NSAIDs). While residue from this pharmaceutical agent has been found in diverse water bodies in various countries, there is not enough information of its potential toxicity on aquatic organisms, particularly in species which are economically valuable due to their high consumption by humans, such as the common carp Cyprinus carpio. This study aimed to evaluate potential DCF-induced oxidative stress in brain, liver, gill and blood of C. carpio. The median lethal concentration of DCF at 96h (96-h LC50) was determined and used to establish the concentration equivalent to the lowest observed adverse effect level (LOAEL). Carp specimens were exposed to this concentration for different exposure times (12, 24, 48, 72 and 96h) and the following biomarkers were evaluated: lipid peroxidation (LPX) and the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Also, the DCF and 4-hydroxy DCF was determined by LC-MS/MS. Results show a statistically significant LPX increase (P<0.05) in liver and gill mainly as well as significant changes in the activity of the antioxidant enzymes evaluated in these organs, with respect to controls (P<0.05). The DCF concentrations decreased in water system and increased in the carp. The DCF biotransformation to 4-hydroxy DCF was observed to 12h. The pharmaceutical agent DCF is concluded to induce oxidative stress on the common carp C. carpio, with the highest incidence of oxidative damage occurring in liver and gill. Furthermore, the biomarkers employed in this study are useful in the assessment of the environmental impact of this agent on aquatic species.

Removal of remazol yellow from aqueous solution using Fe-Cu and Fe-Ni nanoscale oxides and their carbonaceous composites.

Fe-Cu and Fe-Ni nanoscale oxides and their carbonaceous composites (C/Fe-Cu and C/Fe-Ni, 75/25 wt.%; C/Fe-Cu and C/Fe-Ni 95/5 wt.%), made from pyrolysis of sewage sludge, have been evaluated to remove remazol yellow textile dye from aqueous solution. The kinetic and sorption isotherms experimental results were best fitted to the pseudo-second-order kinetic and Langmuir-Freundlich isotherm models, which indicates that the sorption mechanism may be chemisorption onto heterogeneous surfaces. Fe-Ni and Fe-Cu nanoscale oxides adsorption capacities were 157.8 mg/g and 117.6 mg/g, resulting in nearly 83% and 70% of dye removal, respectively, using 100 mg/L of initial dyestuff concentration and 10 mg of each material. The adsorption capacities of Fe-Cu, Fe-Ni oxides and C/FCu 75/25%, C/Fe-Ni 75/25% composites provide better results at pH between 3 and 5. In addition, three sorption-desorption cycles using 30% H2O2 solution and distilled water were performed: sorption efficiencies for all materials decreased after each cycle; nevertheless, Fe-Cu and Fe-Ni nanoscale oxides were the best materials for the removal of remazol yellow dye.

Producción de ácido giberélico a partir de Gibberella fujikuroi utilizando lodo residual municipal como sustrato / Production of gibberellic acid from Gibberella fujikuroi using municipal sewage sludge as a substrate / Produção de ácido giberélico desde Gibberella fujikuroi usando lodo residual municipal como substrato

Objetivo. Utilizar lodos residuales municipales (LRM) provenientes de una planta de tratamiento de aguas residuales ubicada en Toluca, Estado de México, para cultivar al hongo Gibberella fujikuroi en fermentación sumergida y producir ácido giberélico (AG3). Materiales y métodos. Se utilizó Gibberella fujikuroi (CDBB:268). Para la obtención de AG3 se verificó la producción empleando como sustrato al medio de cultivo estándar (MCE). La determinación de (AG ) fue por cromatografía líquida de alta resolución (HPLC) con un equipo Varian, 9050,9012. Se obtuvieron 6 muestras de lodos de una planta tratadora de aguas residuales en Toluca, Estado de México y fueron caracterizados. Finalmente ambos sustratos (LRM y MCE) se usaron en fermentación sumergida y por extracción se obtuvo el AG3 cuantificado por HPLC. Resultados. La caracterización del LRM demostró que el contenido de materia orgánica (MO) es de 5.20 % (m/v) y nitrógeno total (N T) de 0.25 % (m/v), dicha composición está dentro del rango como sustrato para la producción del AG3 por Gibberella fujikuroi. El hongo se cultivó durante 3, 8, 13 y 30 días utilizando lodo residual estéril con una humedad del 95.6 %(m/v) y en medio de cultivo estándar (MCE), las muestras se procesaron y analizaron por cromatografía líquida de alta resolución (HPLC), donde la producción de AG3 en el LRM fue de 460.06 mg/L para 30 días en fermentación sumergida a un pH de 4.0 y 1014.46 mg/L para el control. Conclusiones. El contenido nutritivo del LRM es adecuado para el crecimiento del hongo Gibberella fujikuroi y la producción de AG3 empleando como sustrato LRM.

Objective. To use municipal sewage sludge (LRM) from a wastewater treatment plant located in Toluca, State of Mexico, to grow the fungus Gibberella fujikuroi in submerged fermentation and to produce gibberellic acid (AG3). Materials and methods. We used Gibberella fujikuroi (CDBB: 268). To obtain AG3, production was verified using as a substrate the standard culture medium (MCE). Gibberellic acid determination was done with high performance liquid chromatography (HPLC) with a Varian 9050.9012 equipment. We obtained 6 samples of sludge from a wastewater treatment plant in Toluca, State of Mexico, that were then characterized. Finally, both substrates (LRM and MCE) were used in submerged fermentation, and GA3 was obtained by extraction and quantified using HPLC. Results. The LRM characterization showed that the organic matter content (MO) is of 5.20% (w/v) and the total nitrogen content (N T) is of 0.25% (w/v). Such composition is within the range as a substrate for the production of AG3 by Gibberella fujikuroi. The fungus was cultivated for 3, 8, 13 and 30 days in sterile sewage sludge with a moisture content of 95.6% (w/v) and in standard culture medium (MCE). Samples were processed and analyzed by high performance liquid chromatography (HPLC). Production of AG3 in the LRM was of 460.06 mg/L after 30 days in submerged fermentation at pH 4.0, and of 1,014.46 mg/L in the control. Conclusion. The nutrient content of LRM is suitable for the growth of the fungus Gibberella fujikuroi and for the production of GA3 when used as a substrate.

Objetivo. Usar lodos residuais municipais (LRM) procedentes de uma estação de tratamento de águas residuais de Toluca, Estado de México, para cultivar o fungo Gibberella fujikuroi em fermentação submersa e produzir ácido giberélico (AG3). Materiais e métodos. Foi utilizado Gibberella fujikuroi (CDBB: 268). Para obter AG3 foi verificada a produção empregando como substrato o meio de cultura padrão (MCE). A determinação de ácido giberélico foi por cromatografia líquida de alta eficiência (HPLC) com um equipo Varian, 9050,9012. Foram obtidas seis amostras de lodos de uma estação de tratamento de águas residuais em Toluca, Estado de México e foram caracterizadas. Finalmente, ambos os substratos (LRM e MCE) foram utilizados em fermentação submersa e por extração foi obtido o AG3 quantificado por HPLC. Resultados. A caracterização do LRM demonstrou que o teor de matéria orgânica (MO) é 5,20% (m/v) e o nitrogênio total (N T) 0,25% (m/v), esta composição está dentro do intervalo como substrato para a produção de AG3 por Gibberella fujikuroi. O fungo foi cultivado por 3, 8, 13 e 30 dias usando lodo residual estéril com um teor de umidade de 95,6% (m/v) e em meio de cultura padrão (MEC), as amostras foram processadas e analisadas por cromatografia líquida de alta resolução (HPLC), onde a produção de AG3 no LRM foi 460,06 mg/L para 30 dias em fermentação submersa em pH 4,0 e 1.014,46 mg/L para o controle. Conclusões. O teor nutritivo do LRM é adequado para o crescimento do fungo Gibberella fujikuroi e a produção de AG3, empregando como substrato o LRM.

Physicochemical and biological combined treatment applied to a food industry wastewater for reuse.

The aim of this study was to improve the wastewater treatment plant (WWTP) efficiency of a food industry. Despite the anaerobic-aerobic treatment, the efficiency of the plant is poor because of the high pollutants load derived mainly from the use of disinfectants and sanitizers. These cleaning products are used in the production process. In order to achieve the main goal of the study, the pollutants load reduction was targeted and a physicochemical treatment was added for that purpose. For this effort, the tests were divided in three parts. The first consisted of performing coagulation-flocculation laboratory tests to select the best chemical reagent for reduction of the high load of pollutants present in the influent. The evaluated compounds were ferric chloride, aluminum sulphate, hydroxychloride of aluminum (AHC) and polyaluminum sulphate (PAS). The second was a pilot plant study in which physicochemical and biological treatment werecombined. Finally processes were verified in the WWTP characterizing the effluent and evaluating the process for compliance with standards for reuse water. The results showed that the best coagulant was hidroxichloride of aluminium. Improving the relationship Chemical Oxygen Demand/ Biological Oxygen Demand (COD/BOD(5)) of 0.27 to 0.45 and getting a dose of 1 to 5 mg L(- 1) in the laboratory, which improved to make scaling to plant 0.5 to 2 mg L(- 1) with efficiencies removal of contaminants 98% for COD, 95% for BOD(5), 99% for O&G, to 99% for TSS and helminth eggs were not detect. The wastewater was characterized with cyclic voltammetry and the sludge produced with AHC was analyzed by scanning electron microscopy (SEM) and energy-dispersion spectroscopy (EDS).