Toxicity and biodegradability of olive mill wastewaters in batch anaerobic digestion

The anaerobic biodegradability and toxicity of olive mill waste-waters (OMW) were studied in batch anaerobic digestion experiments. Anaerobic digestion of OMW or the supernatant of its centrifugation, the methane production was achieved at up to 5–15% (V/V) dilution corresponding to only 5–20 g/L COD. The washed suspended solids of OMW were toxic at up to 80 g/L COD; however, the kinetic of biodegradability of OMW or the supernatant was faster than for suspended solids, which are constituted meanly of cellulose and lignin. The darkly colored polyphenols induce the problem of biodegradation of OMW, whereas the long chain fatty acids (LCFA), tannins and simple phenolic compounds are responsible its toxicity for methanogenic bacteria.     

Analysis and anaerobic degradation of wool scouring and olive oil mill wastewaters

Summary Two types of fatty industrial wastewaters, wool scouring effluents (WSE) and olive oil mill effluents (OME) were analysed (lipids, phenols and COD), and were then treated anaerobically in laboratory-scale fixed bed filters. Approximately 50% of the organic compounds in both wastewaters was degraded at two days of hydraulic residence time. A higher biogas production was obtained when using OME rather than WSE. This experimental study confirmed that anaerobic digestion can be considered as a roughing treatment in a multi-step process for industrial fatty wastewaters.     

Stereoselective reductase-catalysed deoxygenation of sulfoxides in aerobic and anaerobic bacteria

Direct and indirect evidence, of unexpected stereoselective reductase-catalysed deoxygenations of sulfoxides, was found. The deoxygenations proceeded simultaneously, with the expected dioxygenase-catalysed asymmetric sulfoxidation of sulfides, during some biotransformations with the aerobic bacterium Pseudomonas putida UV4. Stereoselective reductase-catalysed asymmetric deoxygenation of racemic alkylaryl, dialkyl and phenolic sulfoxides was observed, without evidence of the reverse sulfoxidation reaction, using anaerobic bacterial strains. A purified dimethyl sulfoxide reductase, obtained from the intact cells of the anaerobic bacterium Citrobacter braakii DMSO 11, yielded, from the corresponding racemates, enantiopure alkylaryl sulfoxide and thiosulfinate samples.     

Kinetics of aerobic and anaerobic oxidations of ethanol by Fenton's reagent

For the first time, the time dependence of [H₂O₂] and [Fe²⁺] was followed during the aerobic oxidation of ethanol by Fenton's reagent. It was found that part of the ethanol was oxidized by dissolved O₂ via the transient formation of H₂O₂. A model was set up based on FeO²⁺ as the key intermediate. Both one‐ and two‐equivalent oxidations of ethanol occur, the former producing radical species derived from ethanol. No free radicals derived from H₂O₂ play part in the system. The relevant rate constants or their ratios were determined. The mechanism accounted successfully also for the anaerobic oxidation of ethanol. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 541–553, 2008     

Thermal and photochemical reactions of allylcobaloximes with para-substituted benzenesulphonyl chloride under aerobic and anaerobic conditions

The compounds p-XC₆H₄SO₂Cl (X = Cl, Br, I, OMe) react regiospecifically with allyl-, 2-methylallyl-, 3-methylallyl- and 3,3-dimethylallyl-cobaloximes under thermal and photochernical conditions. A rearranged organic product is obtained in each case. The yields are much better in photochemical reactions. A chain mechanism is involved in which the organosulphonyl radical and cobaloxime(II) are the chain propagating species. Yields of the sulphones are drastically reduced when the reactions are carried out in the presence of oxygen.     

Degradation and metabolism of imazapyr in soils under aerobic and anaerobic conditions

The degradation of imazapyr in four soils was investigated under laboratory aerobic and anaerobic conditions. Under aerobic conditions, imazapyr degraded faster in yellow–red soil than in other soils, and its persistence decreased depending on soil pH in the order coastal soil (pH 8.8)?>?silt-loamy paddy soil (pH 7.9)?>?fluvio-marine yellow loamy soil (pH 7.1)?>?Yellow–red soil (pH 5.3). However, soil pH did not affect imazapyr degradation under anaerobic conditions. The half-lives of imazapyr in soils under aerobic conditions were in the range of 26–44 days estimated by the first-order kinetics model, while 3–10 days calculated by two-stage model under anaerobic conditions. The preceding results demonstrated that anaerobic conditions contributed to imazapyr disappearance in soils. Based on the spectral data of APCI-MS, ¹H NMR and IR, structures of the following metabolites: 2,3-pyridinedicarboxamide, 2,3-pyridinedicarboxylic anhydride and 2,3-pyridinedicarboximide for aerobic treatments; 2,3-pyridinedicarboxylic anhydride and 2-(4-hydroxy-5-oxo-2-imdazolin-2-yl) nicotinic acid for anaerobic treatments, were identified. Degradation mechanism under the different conditions was also discussed.     

Electron spin resonance studies of the anaerobic and aerobic photolysis of alkylcobaloximes

Aerobic and anaerobic photolysis of methyl(pyridine)cobaloxime, benzyl(pyridine)cobaloxime and analogous compounds in CHCl₃ results only in an electron transfer reaction from an equatorial ligand producing photo-reduction of Co^III to Co^II, the complex retaining its axial ligands.If after the anaerobic photolysis of benzyl(pyridine)cobaloxime the oxygen is introduced without any further photolysis we obtain an ESR spectrum of nitroxide, arising from the attack of a benzyl radical on the dimethylglyoxime equatorial ligand.For the other complexes, homolytic cleavage of the CoC bond occurs and in the presence of oxygen gives rise to the superoxide cobalt complex adduct Py(Co^IIIO₂^?.During photolysis of methyl(pyridine)cobaloxime in isopropanol homolytic cleavage of the CoC bond occurs in preference to electron transfer reaction from the equatorial ligands.The anaerobic photolysis of benzyl(pyridine)cobaloxime in isopropanol or in water at 113–133 K results in an electron transfer reaction. However, at 170 K we observe the formation of the Co^II complex arising from CoC bond cleavage.A mechanism for photo-induced insertion of oxygen in the CoC bond is proposed.     

Evaluation of proficiency tests in microbiological analysis: enumeration of aerobic microorganisms

South Korea’s Ministry of Food and Drug Safety (MFDS) has been developing programs for the inspection and accreditation of food sanitation inspection institutions. Food sanitation inspection institutions such as MFDS regional offices, the Research Institute of Public Health and Environment and authorized private service providers in South Korea must participate in proficiency testing (PT) programs to comply with the Food Sanitation Act and MFDS Notification No. 2012-112. As the PT provider, the MFDS annually plans various microbiological and chemical PT programs for foods, cosmetics, and pharmaceutical products in accordance with ISO/IEC 17043. The aim of this project was to evaluate the performance of microbiological PT programs to ensure the quality of their routine test results. The test materials used were freeze-dried BioBalls from BTF Pty Ltd. Homogeneity and stability were investigated to assess the adequacy of the selected test materials. This project also contains data from inter-laboratory comparisons organized by MFDS in 2011 and 2012. More than 50 laboratories attended the PT program and submitted their results. Laboratory results were rated with z-scores according to the international standard ISO 13528. The results from 2011 and 2012 revealed that all participating laboratories had similar levels of proficiency. Most of the participants received a rating of “Satisfactory.” Moreover, the percentage of participants who received a rating of “Unsatisfactory” decreased from 3.5 % in 2011 to 2.0 % in 2012.     

Flow microcalorimetry in monitoring biological activity of aerobic and anaerobic wastewater-treatment processes

A flow microcalorimetric system which is compatible with the experimental conditions of industrial processes was used to monitor the biological activity of wastewater-treatment systems. Two industrial wastewater-treatment processes were investigated: an activated-sludge (aerobic) treatment of a textile factory effluent and a methane fermentation (anaerobic) treatment of effluents from a cheese factory. In both types of system, the heat flux resulting from metabolic reactions during bacterial degradation of organic substances in the effluent could be measured adequately. Depending on the measurements selected, the calorimetric data could be used to monitor the bacterial activity in the bioprocess, or the effluent degradability or toxicity, or the overall content of degradable substrates in the effluent (loading). The non-invasive measurement of heat flux enabled continuous or semi-continuous on-line monitoring of these biological processes. The response time of the flow calorimetric unit is of the order of minutes, thus yielding process data with minimal delay. These data enable rapid intervention to optimize process parameters (e.g., to control the inlet flow rate or dilution, divert or dilute toxic contaminants, etc.).     

Resolution of methyl nonactate by Rhodococcus erythropolis under aerobic and anaerobic conditions

[reaction: see text]. An efficient resolution of methyl nonactate is reported by biotransformation in shake flask cultures of Rhodococcus erythropolis. The equilibrium of the reaction redox system can be manipulated by switching from aerobic to anaerobic growth, thereby generating both enantiomers of the target in excellent yield and enantiomeric purity.     

Application of Photo-Fenton,Electro-Fenton,and Photo-Electro-Fenton processes for the treatment of DMSO and DMAC wastewaters

Biological treatment, due to the formation of hazardous chemicals to remove organic compounds such as dimethyl sulfoxide (DMSO) and N, N-dimethylacetamide (DMAC), has limited potential. Advanced oxidation processes (AOPs) are regarded as a viable alternative for treating molecules containing carbon-hydrogen bonds that cannot be broken down by traditional physico-chemical methods. In this investigation, various AOPs such as Photo-Fenton, Electro-Fenton, and Photo-Electro-Fenton processes were studied to treat wastewaters containing DMSO and DMAC. The effects of the operating parameters, including various initial concentrations of DMSO and DMAC, initial pH, reaction time, different concentrations of Fenton’s reagent, power of UV lamp, different concentrations of electrolytes, the distance between electrodes and current intensity, were investigated. The findings of the experiments revealed that a pH of 3 and a reaction time of 120 min were optimal. At 2000 mg L^?1 of DMSO, maximum degradation and the final concentration of TOC were 98.64 % and 256.8 mg L^?1, respectively, by the Electro-Fenton process under the optimal conditions. The Electro-Fenton process was successful in determining the maximum degradation of DMAC (96.31 %) and the final TOC concentration (10.03 mg L^?1) at 250 mg L^?1 of DMAC under optimal conditions. Finally, it can be concluded that the Electro-Fenton process was the best process for the efficient removal of DMSO and DMAC. The second step of the kinetic model follows a pseudo-first-order reaction for 250 and 500 mg L^?1 of pollutants and obeyed a pseudo-second-order kinetic model for concentrations of 1000, 2000 mg L^?1.     

Sequential injection spectrophotometric determination of orthophosphate in beverages, wastewaters and urine samples by electrogeneration of molybdenum blue using tubular flow-through electrodes

A novel and automated sequential injection procedure is proposed for the spectrophotometric determination of orthophosphate without requiring unstable chemical reducing species used in the classical molybdenum blue method. The flowing methodology is based on the on-line generation of the detectable species by electrochemical reduction of the 12-molybdophosphoric acid complex using a stainless steel tubular flow-through working electrode. The established method is linear up to 20 mg/l P, with coefficients of variation (n=10) of 2.4 and 1.8% for 2.0 and 10 mg/l P, respectively. The versatility of the sequential injection method to analyse samples containing high orthophosphate levels has been demonstrated by the implementation of a dilution chamber as well as flow-reversal techniques, yielding relative standard deviations (n=17) better than 2.0% for standards containing 200 and 800 mg/l P. The proposed analyser features an extremely wide dynamic range (viz., 0.3-800 mg/l) as well as improved tolerance to silicate interference, so that Si/P ratios higher than 50 are tolerated at the 5% level. Electrochemical conditions, reagent concentrations and physical variables have been thoroughly investigated. The method has been applied to the determination of orthophosphate in wastewaters as well as beverages and biological samples containing high concentrations of the target analyte. The t-test comparison of the means for the developed sequential injection system with electroreduction and both the molybdenum blue classical spectrophotometric batch procedure and inductively coupled plasma-optical emission spectrometric detection selected as external reference methods revealed that there is no evidence of significant differences between the obtained results at the 95% confidence level.     

Mechanism and products of thermal treatment of slimes obtained at treatment of wastewaters using ferroferrihydrosol

Phase, dispersion, and chemical compositions of the products of thermal treatment of slimes obtained by treatment of model solutions and industrial wastewaters from electrochemical production using ferroferrihydrosol were studied. The dependence of the phase composition of the slime treatment products as influenced by the content and ratio of heavy metals in wastewaters was evaluated.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 9, 2004, pp. 1520–1524.Original Russian Text Copyright © 2004 by Budilovskis, Eshchenko.     

Some peculiarities of metal migration in the aerobic and anaerobic conditions in the surface water bodies

The results of research on metal migration (Mn, Cu, Zn, Pb, Cr) in the surface water bodies of the different type (the Kiev and the Kanev reservoirs of the Dnieper cascade, and Verbnoye and Telbin lakes of the Kiev city) in dependence on their oxygenous regime are considered. It was shown that the metal migration in the aerobic conditions is mainly directed from water thickness to bottom sediments. In contrast, the migration of metal compounds from bottom sediments in the anaerobic conditions is increased. Manganese is mostly in a form of free ions Mn²⁺ in the pore solutions, therefore, it migrates from bottom sediments in the greatest extent. The migration of other studied metals occurs in a much smaller extent and depends on the migration mobility of organic substances which they are bound to complexes. Migration mobility of copper, lead and chromium decreases essentially when the hydrogen sulphide is in the water of bottom layer. The data on a degree of metal binding to complexes and their chemical nature in water of reservoirs and lakes are given. The greater part of metals is found to be in complex compounds with humic substances in water of the Dnieper reservoirs, whereas in the lakes a share of neutral (mainly with carbohydrates) and cationic (mainly with protein-like substances) complexes essentially increases. The distribution of metals is explained by distinction in a component composition of dissolved organic matters in the reservoirs and in the lakes.     

A mini-review of the electro-peroxone technology for wastewaters: Characteristics,mechanism and prospect

The electro-peroxone technology, a novel type of advanced oxidation technology, is widely used in wastewater treatment. Herein, this paper reviews the advantages and problems of the electro-peroxone technology compared with electrochemical oxidation technology, ozonation technology, and traditional peroxone technology. Due to the high kinetics of pollutant degradation, the electro-peroxone process can reduce the reaction time and energy consumption of pollutant treatment in wastewater. The elect...     

Synthesis, characterization and colour determination using CIELAB colour space of stilbene dyes

The synthesis of six new symmetrical disazo direct dyes containing 4,4′-diaminostilbene-2,2′-disulphonic acid as middle component and N-(2-chlorophenyl)-2-hydroxybenzamide, N-(3-chlorophenyl)-2-hydroxybenzamide, N-(4-chlorophenyl)-2-hydroxybenzamide, N-(2-bromophenyl)-2-hydroxybenzamide, N-(3-bromophenyl)-2-hydroxybenzamide, N-(4-bromophenyl)-2-hydroxybenzamide as coupling components is presented. The synthesized dyes were analyzed by thin layer chromatography, electronic spectra and HPLC technique. Their structures were elucidated by FT/IR and 13C-NMR spectroscopy. The CIELAB (1976) colour space was used in all the colour measurements for the six disazo stilbene dyes under the CIE recommended illuminants: D65 (natural day light), A (tungsten light), F2 (fluorescent light) and the standard 10° observer, respectively. The colour differences: ΔEab* and ΔECMC were calculated against one standard. The results reveal a good colouring power of the new azo-stilbene dyes.     

Sequential electrochemical/biological treatment for the removal of 2,6-dichlorophenol from synthetic wastewater

The paper examines the effect of chloride on the oxidation of 2,6-dichlorophenol (DCP) performed at TiO2/RuO2 DSA anodes, which are specific catalysts for chlorine evolution. The results indicate that chlorine/hypochlorite originating from chloride oxidation in certain favourable conditions reacts with the organic substrate at the diffusion layer near the anode, accelerating the mass transfer of the reactant towards the electrode surface. When the bulk concentration of organic substrate has become very low, the oxidising species can accumulate in the bulk solution where the accomplishment of the oxidation of residual reactant and of its intermediates takes place. Solutions which also contained glucose were electrolysed in order to verify the high level of selectivity of DCP oxidation with respect to a biodegradable substrate: glucose was found to be unchanged up to nearly complete elimination of DCP. The toxicity of the solution was sufficiently reduced to reach values compatible with the subsequent biological treatment.     

Iron-catalyzed aerobic oxidative cross-coupling amidation of N,N-dimethylanilines

An efficient iron-catalyzed dehydrogenative cross-coupling amidation/imidation reaction between N,N-dimethylanilines and amides/imides is reported. The protocol uses an inexpensive and readily available Fe(NO₃)₃·9H₂O/O₂ catalytic system in the absence of additional ligands at room temperature.     

Solid phase microextraction of macrolide, trimethoprim, and sulfonamide antibiotics in wastewaters

In this work, we optimize a solid phase microextraction (SPME) method for the simultaneous collection of antibiotics (sulfonamides, macrolides, and trimethoprim) present in wastewaters. The performance of the SPME method is compared to a solid phase extraction (SPE) method. Analytes in both cases were quantified by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) with electrospray ionization. The advantages offered by SPME in this application are: decreased sample volume requirements, ease of sample processing and extraction, decreased cost, and most importantly, elimination of electrospray matrix effects. Despite having higher limits of quantification (16-1380 ng/L in influent and 35-260 ng/L in effluent), nearly all of the compounds found to be present in Edmonton Gold Bar wastewater by SPE were measurable by SPME (i.e., sulfamethoxazole, trimethoprim, erythromycin, and clarithromycin), with values similar to those obtained using the former method. Limits of quantification for the SPE method for the measured compounds were 4.7-15 ng/L and 0.86-6.1 ng/L for influent and effluent, respectively.