RESUMEN
To investigate effects of earthworms on microbial community structure and metabolic properties of biofilms in vermifiltration for liquid-state sludge stabilization, a vermifilter (VF) with earthworms and a conventional biofilter (BF) without earthworms were compared. The Shannon index of fungi in VF was 16% higher than that in BF, which indicated earthworm activities significantly enhanced fungi diversity. The ratio of monounsaturated to saturated (mono:sat) PLFAs of VF biofilms was higher than that of BF biofilms, which indicated the physiological and nutritional stress for microbial community in VF was relieved due to the increasing of soluble substances caused by the earthworm ingestion. Further investigation showed that the burrowing action of earthworms promoted the aeration condition and led to aerobic microorganisms were predominant in VF. Those results indicated earthworms improved microbial community structure and metabolic properties of biofilms and thus resulted in the overall optimization of the vermifiltration system for liquid-state sludge stabilization.
Asunto(s)
Bacterias/metabolismo , Biopelículas , Ácidos Grasos/análisis , Filtración/métodos , Oligoquetos/metabolismo , Fosfolípidos/análisis , Aguas del Alcantarillado/microbiología , Animales , Bacterias/crecimiento & desarrollo , Biodegradación Ambiental , Biodiversidad , Análisis de la Demanda Biológica de Oxígeno , Biomasa , Reactores Biológicos/microbiología , Oxidorreductasas/metabolismo , Análisis de Componente Principal , Volatilización , Eliminación de Residuos LíquidosRESUMEN
This work illustrated the characteristics and transformation of water extractable organic matter (WEOM) during vermistabilization (Eisenia fetida) of cattle dung by means of chemical and spectroscopic methods. The independent experiment conducted in triplicate was sampled at the 0, 7, 14, 21, 35, 60 and 90days. Results showed that the DOC kept steady around 2.7gkg(-1) after day 60 and the DOC/DON ratio decreased from 19.77 to 5.26 till the end of vermicomposting. On the other hand, vermicomposting decreased the aliphatic, proteinaceous, carbohydrates components and increased the aromaticity and oxygen-containing functional groups in the WEOM. Moreover, fluorescence spectra and fluorescence regional integration (FRI) results indicated that protein-like groups were degraded and fulvic and humic acid-like compounds were evolved during the vermicomposting process. In all, this study suggested the suitability of WEOM for monitoring the organics transformation and assessing the maturity in the vermicomposting.
Asunto(s)
Sustancias Húmicas/análisis , Estiércol/análisis , Oligoquetos/metabolismo , Suelo/análisis , Animales , Carbono/metabolismo , Bovinos , Cromatografía en Gel , Fluorescencia , Nitrógeno/metabolismo , Espectroscopía Infrarroja por Transformada de Fourier , Factores de TiempoRESUMEN
The chemical changes of water-extractable organic matter (WEOM) from five different substrates of sewage sludge enriched with different proportions of cow dung after vermicomposting with Eisenia fetida were investigated using various analytical approaches. Results showed that dissolved organic carbon, chemical oxygen demand, and C/N ratio of the substrates decreased significantly after vermicomposting process. The aromaticity of WEOM from the substrates enhanced considerably, and the amount of volatile fatty acids declined markedly, especially for the cow dung substrate. Gel filtration chromatography analysis showed that the molecular weight fraction between 10(3) and 10(6) Da became the main part of WEOM in the final product. 1H nuclear magnetic resonance spectra revealed that the proportion of H moieties in the area of 0.00-3.00 ppm decreased, while increasing at 3.00-4.25 ppm after vermicomposting. Fluorescence spectra indicated that vermicomposting caused the degradation of protein-like groups, and the formation of fulvic and humic acid-like compounds in the WEOM of the substrates. Overall results indicate clearly that vermicomposting promoted the degradation and transformation of liable WEOM into biological stable substances in sewage sludge and cow dung alone, as well as in mixtures of both materials, and testing the WEOM might be an effective way to evaluate the biological maturity and chemical stability of vermicompost.
Asunto(s)
Estiércol , Oligoquetos , Eliminación de Residuos/métodos , Aguas del Alcantarillado , Animales , Análisis de la Demanda Biológica de Oxígeno , Carbono/análisis , Bovinos , Cromatografía en Gel , Ácidos Grasos Volátiles/análisis , Espectroscopía de Resonancia Magnética , Nitrógeno/análisis , Espectrometría de FluorescenciaRESUMEN
A new adsorbent system for removing methylene blue (MB) from aqueous solutions has been investigated. This new adsorbent is cereal chaff, an agriculture product in middle-west region in China. Variables of the system, including biosorption time, chaff dose, pH, salt concentration and initial MB concentration, were adopted to study their effects on MB removal. The results showed that as the dose of chaff increased, the percentage of MB sorption increased accordingly. There was no significant difference in the dye concentration remaining when the pH was increased from 4.0 to 11.0. The salt concentration has negative effect on MB removal. At the experimental range of MB concentration, the amount of MB adsorbed onto per unit mass of chaff (q(e)) is direct ratio to MB initial concentration (c(0)). The equilibrium data were analyzed using five equilibrium models, the Langmuir, the Freundlich, the Redlich-Peterson, the Koble-Corrigan and the Temkin isotherms. The results of non-linear regressive analysis are that the isotherms of Langmuir, Redlich-Peterson and Koble-Corrigan are better fit than the isotherms of Freundlich and Temkin at different temperatures according to the values of determined coefficients (R(2)) and Chi-square statistic (chi(2)). The maximum equilibrium capacities of chaff from Langmuir models are 20.3, 25.3 and 26.3 mg g(-1) at 298, 318 and 333K, respectively. Using the equilibrium concentration constants obtained at different temperatures, various thermodynamic parameters, such as DeltaG(0), DeltaH(0) and DeltaS(0), have been calculated. The thermodynamics parameters of MB/chaff system indicate spontaneous and endothermic process. It was concluded that an increase in temperature results in a bigger MB loading per unit weight of the chaff.
Asunto(s)
Azul de Metileno/análisis , Triticum/química , Eliminación de Residuos Líquidos/métodos , Purificación del Agua/métodos , Adsorción , Agricultura/métodos , Concentración de Iones de Hidrógeno , Residuos Industriales , Cinética , Azul de Metileno/química , Modelos Químicos , Temperatura , Termodinámica , Agua , Contaminantes Químicos del Agua/análisis , Contaminación Química del AguaRESUMEN
The suspended substance (SS) in the effluent from eco-biofilters was examined by elemental analysis and infrared spectroscopy. The inorganic components of SS in D1 and S1 are more than those in D2 and S2, respectively. The IR spectra of SS is mainly composed of the adsorption of carbohydrates, protein, etc. The domninating bands near 1655, 1542 and 1240 cm(-1) are assigned to amide I, amide II and amide III respectively, and the characteristic IR absorption of protein could be one of the significant components of cell walls. The peak near 1460 cm(-1) is attributable to the bending stretching of CH1-- and CH3--. The strength of adsorption peaks in the region 1720-1200 cm(-1) for D1 is lower than that for D2, but at 1040 cm(-1) the case is reversed.
Asunto(s)
Espectrofotometría Infrarroja/métodos , Filtración , SuspensionesRESUMEN
The experimental research on the static degradation and treatment of groundwater contaminated by herbicide atrazine was conducted by using bacterium AT which was isolated from the sludge outlet of workshop of the pesticide factory. And the result indicated that bacterium AT had the ability of degradation of atrazine with pH ranged from 5.0 to 10.0, and the optimum extent was 6.5-8.0. The experimental conditions (pH = 7.5, t = 10 degrees C) were similar to that of the aquifer in study area. Then the rate of degradation of atrazine was up to 31.08% for one addition of bacterium AT. And the environmental factors changed simultaneously in the course of experiment such as DO, pH and etc. decreasing with the reducing of concentration of bacterium AT. In addition, a mode of dropping bacteria was designed to simulate the condition of throwing bacteria in field. And the permeability of aquifer decreased 60.54% after treatment and the renewals were 48.96% after washing with clean water for 10 days, which indicated the method of renewal is effectual.