RESUMEN
The textile industry generates significant amounts of wastewater containing high concentrations of azo dyes. An important point in the process of purification of azo dyes is their influence on the activated sludge (AS) in wastewater treatment plants. Azo dyes, such as amaranth, play the role of xenobiotics. This article seeks to answer the question of how organisms manage to respond to xenobiotics remains very important and open, i.e., how they will react to toxic conditions. The aim of this research was to study how these changes are expressed in terms of the different trophic levels of AS. In our experiment, it was found that the dominant trophic units are significantly changed due to the xenobiotic entering the system. The data reveal the significant development of the bacterial segment (genus Pseudomonas and azo-degrading bacteria) at times of large amaranth removal. In the most active phase of amaranth biodetoxification (48 h), the culturable bacteria of the genus Pseudomonas change by about 40%, while the azo-degrading bacteria change by about 2%. Fauna organisms have a sharp change in the dominant groups-from attached and crawling ciliates and testate amoebas to the mass development of small and large flagellates. This is of great importance because micro- and metafauna play an important role in the detoxification process by ingesting some of the xenobiotics. This role is expressed in the fact that after dying, macro-organisms release this xenobiotic in small portions so that it can then be effectively degraded by adapting to the amaranth biodegradation bacteria. In this study, it is clear that all these events lead to a decline in the quality of AS. But on the other hand, these allow AS to survive as a microbial community, and the fauna segment does not disappear completely.
Asunto(s)
Compuestos Azo , Aguas del Alcantarillado , Aguas del Alcantarillado/química , Compuestos Azo/química , Xenobióticos/metabolismo , Colorante de Amaranto/química , Aguas Residuales , Bacterias/metabolismo , Biodegradación Ambiental , Colorantes/químicaRESUMEN
Plasma-based technologies take an increasing place in the new conceptions of wastewater management as a promising tool for the treatment of persistent organic pollutants with low biodegradability. Plasma major advantage is the synergy of diverse active components with high oxidative action and additional benefits as disinfection of treated water. But the bactericidal effect of plasma can influence the treatment effectiveness when this technology is used in combination with biological methods for the removal of pollutants. The aim of this paper is to study the effect of non-thermal atmospheric plasma torch on key enzymes from phenol biodegradation pathways in Pseudomonas aureofaciens (chlororaphis) AP-9. The strain was isolated from contaminated soils and had a high potential for biodegradation of aromatic compounds. The used plasma source is surface-wave-sustained discharge operating at 2.45â GHz in argon produced by an electromagnetic wave launcher surfatron type. The enzyme activities of phenol 2-monooxygenase (P2MO), catechol 1,2-dioxygenase (C12DO), catechol 2,3-dioxygenase (C23DO), protocatechuate 3,4-dioxygenase (P34DO) and succinate dehydrogenase (SDH) were measured in control and after plasma treatment of 10, 30 and 60â s. At short-time treatment, the activities of intradiol dioxygenases increased with 26% and 59% for C12DO and P34DO, respectively. Other oxygenases and SDH were inhibited with 35% even at 10â s treatment. Longer treatment times had a clear negative effect but SDH kept the higher activity at 60â s treatment compared to the oxygenases. Our data suggest that plasma-based technologies are a useful approach for post-treatment of aryl-containing wastewater in order to increase the effectiveness of biological removal.
Asunto(s)
Dioxigenasas , Gases em Plasma , Purificación del Agua , Biodegradación Ambiental , Oxigenasas , PseudomonasRESUMEN
The shock loading of wastewater treatment plants (WWTPs) with toxic pollutants remains a critical problem with crucial significance for the technologies. On 5 November 2014, 30 tons of mazut were emitted in Sofia's WWTP 'Kubratovo', passing through equipment and damaging the functioning of the technological modules. The rehabilitation of activated sludge (AS) after shock loading as well as the development of detoxification activity were investigated. The hydrocarbon index of petroleum products, filamentous index (FI), sludge biotic index, sludge volume index (SVI), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), oxygenases and succinate dehydrogenase activities were analyzed for a period of two weeks. The results show that independently from prolonged rehabilitation period, AS remained with filamentous bulking (SVI over 200 ml/g and FI over 1.107 µm/mg). At the same time, the detoxification potential of the AS was developed. Although the morphological and functional structure was still not fully recovered, the AS developed two adaptive mechanisms. First, activation of shorter, more effective ways for benzene ring cleavage, operated by catechol 2,3-dioxygenase; second, strong increase of succinate dehydrogenase activity, which is consistent with the activation of the degradation of trivial substrates for energy generating to overcome the intoxication and synthesis of oxygenases.
Asunto(s)
Aguas del Alcantarillado , Aguas Residuales , Análisis de la Demanda Biológica de Oxígeno , Petróleo , Eliminación de Residuos LíquidosRESUMEN
Nanobiotechnologies are a rapidly growing field that offers new opportunities thus far unknown including regulation processes at a nano level. The biodetoxification and mechanisms of degradation of many xenobiotics have been studied and are well documented. There remains the important issue of the impact of nanomodulators on biodetoxification processes and their potential to optimize and regulate biodegradation of recalcitrant xenobiotics. The purpose of the present study is to clarify in comparative terms the effect of carbon nanoparticles (single-walled nanotubes and nanodiamonds) on these processes. In order to achieve this objective analogous modeling of biodegradation processes was performed. The experiment was conducted in simplified conditions, using a microbial culture of Pseudomonas sp. We observed the influence of nanodiamonds (ND) and single-walled nanotubes (SWNT) on the basic kinetic parameters and key oxygenase enzymes of the bacteria from the genus Pseudomonas in the course of a model phenol biodegradation process. The results confirm the stimulating effect of ND on the initial stages of the biodetoxification processes. In comparison to the control variant there was an increase in the specific rate of phenol biodegradation (154%) and in the effectiveness of phenol elimination (151%). ND increase the activities of phenol-2-monooxygenase and catechol-2,3-dioxygenase respectively by 63,91% and 63,94% in comparison to the control variant. Under the same conditions SWNT have positive influence on the catechol-1,2-dioxygenase activity by 30,12% in comparison to the control. The data from this study are optimistic in relation to the future application of carbon nanoparticles, such as specific nanomodulators in bioremediation technologies for sediments, activated sludge, compost and other resources, polluted with xenobiotics.
Asunto(s)
Biodegradación Ambiental , Nanodiamantes/química , Nanotubos/química , Fenol/aislamiento & purificación , Pseudomonas/metabolismo , Fenol/toxicidad , Pseudomonas/química , Pseudomonas/enzimologíaRESUMEN
The Middle Iskar cascade is situated along the middle course of the Iskar River (Bulgaria) after the capital city Sofia and has three small hydroelectric power plants that were put into operation by the end of 2012. The aim of this study was to evaluate the self-purification potential of water in the reservoirs of these plants as an important and necessary condition for their ecological functioning. The assessment was made by hydrochemical parameters (dissolved suspended solids, insoluble suspended solids, total suspended solids, nitrites, nitrates, ammonium, phosphates, chemical oxygen demand, dissolved oxygen) and microbiological parameters (aerobic heterotrophic bacteria and bacteria growing in an Endo medium) and covered a period of three years (2010, 2011 and 2012). Standard methods were applied, mainly colorimetric and microbiological cultivation methods. The obtained results showed high levels of some of the tested indicators during 2012. In the section of the Middle Iskar cascade a high self-purification potential was observed in the reservoirs which maintain good water quality.