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Reduced volatile sulfur compounds emitted from e.g. livestock production and biogas production facilities contribute to general air pollution and local odour nuisance. Improved technologies are required to mitigate the emissions of both hydrogen sulfide and organic sulfur compounds. The present study examines the oxidative absorption of reduced sulfur compounds, i.e. hydrogen sulfide, methanethiol and dimethyl sulfide in a wet oxidation process with cupric chloride. It was found that this process efficiently removes both hydrogen sulfide and methanethiol with removal efficiencies >94% under all process conditions tested, while the removal of dimethyl sulfide was in the range 20–40%. The main products determined were dimethyl disulfide, dimethyl trisulfide and elemental sulfur. It was shown that the process was more efficient than the similar process with ferric ions and higher removal could be obtained with lower residence times. Furthermore, though employing cupric ion as metal catalysts results in the production of gaseous sulfur compounds, it is estimated that this process is efficient for deodorization due to the higher odour threshold values of the product compounds and the pH range is optimal for gas streams containing CO 2.

The proposed method for calculation of the energy value of culture media is based on stoichiometric properties of biological oxidative reactions in the cell and allows for assessment of the nutritional value of organic substrates with consideration of their elemental composition. Three organogen elements (carbon, hydrogen and oxygen) participate in the third stage of catabolism, which is the universal way of biological oxidation of organic nutritive substrate compounds. Their content in the composition of an organic compound (or food substrate) allows for calculation of the amount of energy converted into work during cellular metabolism. The idea to calculate the energy value of a food substrate is based on the principle of energetic conjugation, according to which the useful energy of food substrates within the cell is accumulated in the energy-rich adenosine triphosphate (ATP) bonds formed by biological oxidation of the substrate. Calculation of the energy values of organic substrate is traditionally based on the energy of the abiotic oxidation. The proportion of the useful energy converted into work is not considered in this case. The inherent problem of this approach is that the amount of ATP has been calculated only for several universal metabolites with known oxidative pathways, such as pyruvate and acetate. The proposed method is based on stoichiometric patterns and makes it possible to calculate the amount of ATP from the elemental composition of compounds and the mass fractions of carbon, hydrogen and oxygen. The results of calculation of biological oxidation energy obtained by this method coincide with the published data on biological oxidation metabolites in the citric acid cycle. The presented method, based on the composition of the compounds, allows for calculation of the energy value of any food substrate or culture medium containing a variety of organic compounds, including the case when their metabolic pathway of biological oxidation is unknown and the calculation of the bioenergetic value seems impossible.

The article deals with a superfamily of monooxygenases, a multienzymeproteinaceous complex containing cytochrome P450 as a terminal electron acceptor. Due to the low substrate specificity, this monooxygenase actively participates in biosynthesis and oxidation of numerous endogenous cell compounds, and also in oxidation and detoxification of wide spectrum of compounds that are foreign to an organism (xenobiotics). The main peculiarity of animal monooxygenase is its interaction with the membrane: all three components of it are true membrane proteins that gain some advantages (binding of hydrophobic substrates to cytochrome P450, creation of optimal conditions by reaction with its own reductase, modulation of electron transport, etc) over other soluble oxidases. In plants, cytochrome P450 is embedded in the membrane but simultaneously, it occurs in a soluble form as well. As a result, a stronger protection barrier against the impact of xenobiotic-toxicants is created in it. In addition, it is shown that in plants, the same isoforms of cytochrome P450 participate in biosyntheses and xenobiotic degradation. Penetration of xenobiotics into a plant cell and especially, its polarity represents a regulatory signal, which ensures proper distribution of hemoprotein pool in these processes. Action mechanism of cytochrome P450, i.e. the functioning of monooxygenase cycle and its completion stage, when oxygen activated by two electrons is inserted into the substrate and hydroxylation product is formed, is described in more detail. Nowadays, functional models of monooxygenases are used effectively to study this stage. It is considered that in oxygenase reaction, oxygen atom formed by its interaction with ferric ion complex and redox-active ligand is transferred to the substrate via so-called oxenoid mechanism. The rate of the whole hydroxylation process is limited by the stage of insertion of activated oxygen into the substrate. It deserves consideration that hydroperoxides, which are reduced by two electrons and perform shunting of the cycle, model incompletely its operation. Action mechanism of monooxygenase essentially differs from this model and the cycle prefers phasic successive proceeding.

Great progresses have been made to carry out Fenton oxidation under neutral or alkaline pH in which, nevertheless, organic acids and other acidic intermediates usually result in acidic Fenton effluent. To eliminate the classical neutralization step prior to biological treatment, acid-tolerant microbes were here screened and used for purification of acidic Fenton effluent to achieve pH increase and further COD (chemical oxygen demand) removal. The bacterial and fungal community diversity was analyzed before and after screening for acid-tolerant microbes. After screening the bacterial diversity sharply decreased while the fungal diversity at the genus level became richer, mainly including Phialemoniopsis (relative abundance 38.69%), Vanrija (20.08%), Hypocreaceae (18.44%) and Candida (14.74%). Acidic pH and residual H2O2 are the features of Fenton effluent; hence, effects of pH and H2O2 on the screened acid-tolerant microbes were investigated in the aspects of growth rate and oxygen uptake rate. The kinetic parameters, including YH–biomass yield coefficient; Kd–biomass decay coefficient; μm–specific maximum COD removal rate; Ks–half saturation constant for COD removal, of the acid-tolerant microbes using 1/5 YM (yeast extract and malt extract culture medium) as substrate at 25 °C were measured by respirometric methodology. In BAC (biological activated carbon) inoculated with acid-tolerant microbes to treat actual Fenton effluent, the average COD removal efficiency was 72% at HRT (hydraulic retention time) of 3 h and the effluent pH was above 6 after removing the dissolved CO2 by air stripping. This study will provide a basis for developing a new combined process including Fenton and biological oxidation without pH adjustment.

Dye wastewater is one of typically non-biodegradable industrial effluents. A new process linking Fenton’s oxidation with biological oxidation proposed in this study was investigated to degrade the organic substances from real dye wastewater. During the combination process, the Fenton’s oxidation process can reduce the organic load and enhance biodegradability of dye wastewater, which is followed by biological aerated filter (BAF) system to further remove organic substances in terms of discharge requirement. The results showed that 97.6% of chemical oxygen demand (COD) removal by the combination process was achieved at the optimum process parameters: pH of 3.5, H2O2 of 2.0 mL/L, Fe(II) of 500 mg/L, 2.0 h treatment time in the Fenton’s oxidation process and hydraulic retention time (HRT) of 5 h in the BAF system. Under these conditions, COD concentration of effluent was 72.6 mg/L whereas 3020 mg/L in the influent, thus meeting the requirement of treated dye wastewater discharge performed by Chinese government (less than 100 mg/L). These results obtained here suggest that the new process combining Fenton’s oxidation with biological oxidation may provide an economical and effective alternative for treatment of non-biodegradable industrial wastewater.

Almost all present biological processes for treating municipal wastewater have been developed based on the philosophy of biological oxidation with high energy consumption and generation of waste sludge. Given such a situation, the fundamental question of what are the possible ways towards energy self-sufficient biological reclamation of municipal wastewater needs to be addressed urgently. Therefore, this review aims to offer a critical view and a holistic analysis of biological treatment processes with the focus on energy self-sufficiency which indeed is a game changer in the future technology development. The way towards energy self-sufficient operation of biological processes is to maximize energy recovery, while to minimize energy consumption. The examples of such process configurations known as A-B processes are thus discussed. Consequently, this review may offer in-depth insights into the possible directions towards the next-generation biological processes for municipal wastewater reclamation which should be designed as a water-energy-resource factory.

The occurrence of discolored drinking water at customers’ taps, which is mainly caused by the deposition and release of iron (Fe) and manganese (Mn) in water distribution networks (WDNs), is a major worry for both customers and water companies. In this paper, two hierarchical fuzzy inference systems (FISs) to predict Fe and Mn accumulation potential in WDNs were developed. They were also able to indicate the causes of Fe and Mn accumulation potential failures. The FISs could be of great benefit to water resource engineers and drinking water supply companies in managing water discoloration.

This study focussed on evaluating the effect of hydrogen sulfide (H 2 S) on biological oxidation of waste methane (CH 4 ) gas in compost biofilters, Batch experiments were conducted to determine the dependency of maximum methane oxidation rate (V max ) on two main factors; pH and moisture content, as well as their interaction effects. The maximum V max was observed at a pH of 7.2 with decreasing V max values observed with decreasing pH, irrespective of moisture content. Flow-through columns operated at a pH of 4.5 oxidized CH 4 at a flux rate of 53 g/m 2 /d compared to 146 g/m 2 /d in columns operated at neutral pH. No oxidation activity was observed for columns operated at pH 2.5, and DNA sequencing analysis of samples led to the conclusion that highly acidic conditions were responsible for inhibiting the ability of methanotrophs to oxidize CH 4 . Biofilter columns operated at pH 2.5 contained only 2% methanotrophs (type I) out of the total microbial population, compared to 55% in columns operated at pH 7.5. Overall, changes in the population of methanotrophs with acidification within the biofilters compromised its capacity to oxidize CH 4 which demonstrated that a compost biofilter could not operate efficiently in the presence of high levels of H 2 S.

In order to improve the biological oxidation and phosphorous removal in BAF, compound inoculation method was introduced to start two stage biological filters by alternative aeration. The two stage biological filters were connected by serial way, and three phases "batch aeration phase, the phase of small flow water for gradually increasing in the load, the alternative aeration phase" were adopted as the start up procedure. The experimental results showed that: COD removal rate was 83.3% after the former two stages; Ammonia nitrogen removal rate was stable at 81.5% while the TP removal efficiency was 68.9% and COD removal rate reached above 80% at the end of the third phase. Totally, 25 days were necessary for the biofilm formation in two stages BAF.

The occurrence of discoloured water at the customers’ tap is a great worry for water companies throughout the world. Customers’ express their dissatisfaction when their tap water discolour. This greatly undermines their confidence in water companies. This discolouration is mainly caused by increased levels of Fe and Mn accumulation. This paper presents analysis of a six-year dataset comprising of 36 water quality parameters and customer complaints data covering 176 different district metered areas (DMAs) to identify relevant parameters that influence Iron (Fe) and Manganese (Mn) accumulation potential. Customer complaints data were also investigated for seasonal trends. From the analysis of the data, it was observed that of the 36 parameters only few parameters such as those related to bio-chemical oxidation and sorption significantly influenced the accumulation of Fe and Mn. Majority of the DMAs showed significantly high peaks of customer complaints during summer. These spikes may be attributed to increased water consumption and warmer water temperatures during this period.

The effects of ammonia (NH3) on CH4 attenuation in landfill cover materials consisting of landfill cover soil (LCS) and aged municipal solid waste (AMSW), at different CH4 concentrations, were investigated. The CH4 oxidation capacities of LCS and AMSW were found to be significantly affected by the CH4 concentration. The maximum oxidation rates for LCS and AMSW were obtained at CH4 concentrations of 5% and 20%(v/v), respectively, within 20 days. CH4 biological oxidation in AMSW was significantly inhibited by NH3 at low CH4 concentrations (5%, v/v) but highly stimulated at high levels (20% and 50%, v/v). Oxidation in LCS was stimulated by NH3 at all CH4 concentrations due to the higher conversion of the nitrogen in NH3 in AMSW than in LCS. NH3 increases CH4 oxidation in landfill cover materials.

The aim of the present study was to evaluate the biological oxidation of sulphide in two different UASB reactors by assessing the occurrence of oxidized forms of sulphur in the effluents and the amount of S0 that could be recovered in the process. The bioreactors employed were an anaerobic hybrid (AH) reactor employing porous polyurethane foam as support media and a micro-aerated UASB reactor equipped with an aeration device above the digestion zone. The AH reactor produced a final effluent containing low concentrations of S2- (3.87% of total sulphur load). It was achieved due to a complete oxidation of 56.1% of total sulphur. The partial biological oxidation that occurred in the AH reactor allowed the recovery of 30% of the sulphur load as S0. The effluent from the micro-aerated UASB reactor contained 5% of the sulphur load in the form of S2-, while 20.9% was present as dissolved SO42- and 46% was precipitated as S0. It is concluded that the AH reactor or micro-aeration carried out above the digestion zone of the UASB reactor favoured the biological oxidation of S2- and the release of odourless effluents. Both technologies represent feasible and low-cost alternatives for the anaerobic treatment of domestic sewage.

The role of metal ions in biological oxidation - the past and the presentTwo theories, one based on the metabolism of inorganic substances, the other on metabolism of organic substances, have played an important role in the explanation of the origin of life. They demonstrate that the original environment of life on Earth was seawater containing micronutrients with structural, metabolic and catalytic activity. It is assumed that the first primitive organisms lived around 3.8 billion years ago and it was also then that the first catalytic reaction involving metal ions occurred. Biological oxidation leading to oxidative stress and cell damage in animals represents one of these types of reactions which are responsible for many animal diseases. The role of prooxidative and antioxidative actions of transition metal ions as well as their neuropathological consequences have therefore been the topic for many research projects. There is hope that metal chelates and antioxidants might prove to be a modern mode of therapy for i.e. neurogenerative diseases. The aim of this review is to show the evolution of scientific knowledge on metal ions, their biological oxidation, and an overview of their role in physiology and in pathological processes.

Biological Aerated Filter (BAF) has been global applied in secondary and tertiary wastewater treatment process in the past decades. As the increasing application of BAF, it was required to get deeper understanding of the operational discipline, parameter optimization and structural characteristics of BAF to improve the treatment efficiency and to operate stability constantly. In this paper, a physical filtration equation of clean filter bed was established firstly based on an average porosity ratio equation and Kozeny-Carman filtration equation. And then the influence of biological oxidation and biofilm development were introduced, of which the Eckenfelder mode and oxygen transfer were considered, to induce a hybrid physical- biologically equation to describe the headloss development in the BAF.

Aged refuse from waste landfills closed for eight years was examined and found to contain rich methanotrophs capable of biooxidation for methane. Specially, community structure and methane oxidation capability of methanotrophs in the aged refuse were studied. The amount of methanotrophs ranged 61.97 × 10 3 −632.91 × 10 3 cells/g (in dry basis) in aged refuse from Shanghai Laogang Landfill. Type I and II methanotrophs were found in the aged refuse in the presence of sterilized sewage sludge and only Type I methanotrophs were detected in the presence of nitrate minimal salt medium (NMS). The clone sequences of the pmoA gene obtained from the aged refuse were similar to the pmoA gene of Methylobacter, Methylocaldum , and Methylocystis, and two clones were distinct with known genera of Type I methanotrophs according to phylogenetic analysis. Aged refuse enriched with NMS was used for methane biological oxidation and over 93% conversions were obtained.

A study was conducted to evaluate sulfate release kinetics in two different texture of calcareous soil (clay and loamy sand) amended with different levels of agricultural sulfur and to select the best mathematical models which describes the mechanism of biological oxidations of sulfur under different time of incubation. Agricultural sulfur was mixed with soils at rates (0, 5, 10, 20) gm.S-1. kg-1 soil. Water was added to raise the soil moisture content to field capacity, the soil samples were incubated at 298° K. Sulfate release was monorated by using anion capsule resin (OH-resin) inserted in soil for 1, 7, 14, 21, 35 day. Five kinetics models (zero order, first order, parabolic diffusion, Elovich and power function). Were applied to describe sulfate and hydrogen release rate coefficient, in order to select the best model the results showed a significant increase in the accumulated sulfate release with sulfur treatments with increasing. The results showed a significant increase in accumulated H and SO4= release with sulfur treatment with increasing incubation period. The result showed also that parabolic diffusion equation was the best one to describe the rate coefficient of H+ and SO4= that range from 21 to 78 in clay soil and 19 – 69 day -12 in loamy soil for hydrogen release while the rate coefficients of SO4= release were ranged from 9 to 36 and 19 to 47 day -12 for clay and loamy soils respectively.

Many key components of implantable medical devices are made from polymeric materials. The functions of these materials include structural support, electrical insulation, protection of other materials from the environment of the body, and biocompatibility, as well as other things such as delivery of a therapeutic drug. In such roles, the stability and integrity of the polymer, over what can be a very long period of time, is very important. For most of these functions, stability over time is desired, but in other cases, the opposite–the degradation and disappearance of the polymer over time is required. In either case, it is important to understand both the chemistry that can lead to the degradation of polymers as well as the kinetics that controls these reactions. Hydrolysis and oxidation are the two classes of reactions that lead to the breaking down of polymers. Both are discussed in detail in the context of the environmental factors that impact the utility of various polymers for medical device applications. Understanding the chemistry and kinetics allows prediction of stability as well as explanations for observations such as porosity and the unexpected behavior of polymeric composite materials in some situations. In the last part, physical degradation such interfacial delamination in composites is discussed.

Hydrogen Sulfide (H2S) is an odourous, highly toxic gas commonly encountered in various commercial and municipal sectors. Three novel, laboratory-scale, Horizontal-Flow Biofilm Reactors (HFBRs) were tested for the removal of H2S gas from air streams over a 178-day trial at 10 degrees C. Removal rates of up to 15.1 g [H2S] m(-3) h(-1) were achieved, demonstrating the HFBRs as a feasible technology for the treatment of H2S-contaminated airstreams at low temperatures. Bio-oxidation of H2S in the reactors led to the production of H+ and sulfate (SO42-) ions, resulting in the acidification of the liquid phase. Reduced removal efficiency was observed at loading rates of 15.1 g [H2S] m(-3) h(-1). NaHCO3 addition to the liquid nutrient feed (synthetic wastewater (SWW)) resulted in improved H2S removal. Bacterial diversity, which was investigated by sequencing and fingerprinting 16S rRNA genes, was low, likely due to the harsh conditions prevailing in the systems. The HFBRs were dominated by two species from the genus Acidithiobacillus and Thiobacillus. Nonetheless, there were significant differences in microbial community structure between distinct HFBR zones due to the influence of alkalinity, pH and SO4 concentrations. Despite the low temperature, this study indicates HFBRs have an excellent potential to biologically treat H2S-contaminated airstreams. This work was supported by Science Foundation Ireland [grant number 08/RFP/ENM1762] and a European Research Council Starting Grant (3C-BIOTECH; no. 261330). peer-reviewed

While the significance of the redox metal oxo moieties has been fully acknowledged in versatile oxidation processes, active metal hydroxo moieties are gradually realized to play the key roles in certain biological oxidation events, and their reactivity has also been evidenced by related biomimic models. However, compared with the metal oxo moieties, the significance of the metal hydroxo moieties has not been fully recognized, and their relationships in oxidations remain elusive until recently. This review summarizes the reactivity of the metal oxo and hydroxo moieties in different oxidation processes including hydrogen atom transfer, oxygen atom transfer and electron transfer, and their reactivity similarities and differences have been discussed as well. Particularly, how the physicochemical properties like metal–oxygen bond order, net charge and potential of a redox metal ion affect its reactivity has also been presented based on available data. We hope that this review may provide new clues to understand the origins of the enzyme's choice on them in a specific event, to explain the elusive phenomena occurring in those enzymatic, homogeneous and heterogeneous oxidations, to design selective redox catalysts and control their reactivity.

Irradiation with ultrasound (US) and use of an enzyme (E) as pretreatment techniques were carried out to treat a complex effluent (distillery wastewater). These two techniques have been used alone as well as in combination and the efficacy of these techniques was tested by subjecting the effluent to subsequent aerobic biological oxidation (AO). When used alone, US exposure for 30 min and 2 h yielded the best COD reduction during the aerobic oxidation step (US+AO). For the enzyme when used alone, a pH value of 4.8 (corresponding to the optimum pH of the enzyme), a dose of 50 U and a pretreatment time of 24 h yielded better COD removal efficiency as compared to untreated effluent (aerobic oxidation alone). When used in combination, ultrasound followed by enzymatic pretreatment (US+E+AO) yielded the best COD removal efficiencies during aerobic oxidation as compared to the other combinations tested for the treatment of the distillery wastewater. A 4-fold increase in the initial oxidation rate was observed over the untreated batch for the integrated technique (US+E+AO). On the basis of the variation in the values of the biokinetic parameters it can be concluded that the type of pretreatment scheme affects the subsequent rate of the aerobic oxidation significantly.

The products of chemical and biological oxidation (hydroxy, oxo, and acid derivatives) of 1,8-cineole (3,3-dimethyl-2-oxabicyclo[2.2.2]octane) are reviewed with a focus on the diverse regio- and stereoselectivities obtained from this meso monoterpenic compound abundantly present in eucalyptus leaves. Physical properties (melting-point and specific rotation values) as well as 1H and 13C NMR spectroscopic data of oxidized derivatives have been exhaustively compiled with particular attention on the clarification of some literature inconsistencies owing to different carbon numbering and stereochemical denominations. Analytical and synthetic methods, and formation as metabolites by plants, microorganisms, and animals are also reviewed together with their presently known biological activities.

Ferric iron acted as a non-competitive inhibitor for the biological oxidation of ferrous iron and decreased the inhibitory effects of high concentrations of ferrous iron as well as the auto-inhibitive effect the bacterial cells. A previously developed kinetic model for this reaction was modified to incorporate the inhibition effects of ferric iron. © Rapid Science Ltd. 1998

Semicontinuous activated-sludge (SCAS) units inoculated with activated sludge from a plant treating predominantly domestic wastewater were used to study EDTA removal from wastewater at different pH values. Almost complete removal of EDTA was found in units maintained at pH > 8·0, but high EDTA removal was obtained only in SCAS units run with sludge retention times ≥ 12 days. A maximum EDTA removal rate of 0·2 kg EDTA/m 3 /day was achieved in the SCAS units. A full-scale activated-sludge system operating under alkaline conditions provided high removal percentages, confirming the removal of EDTA in activated-sludge systems as established in the SCAS tests. The results in both laboratory and full-scale activated-sludge units showed that a reduction of more than 90% of the incoming EDTA was attainable. Ratios of biological oxygen demand to theoretical oxygen demand of > 0·6 in closed-bottle tests, inoculated with either sludge from a full-scale treatment plant or an SCAS unit, proved that EDTA was removed by biodegradation. These results clearly demonstrated that EDTA-containing wastewater is amenable to activated-sludge treatment in conventional plants operated under alkaline conditions.

The objective of this work was to study the effect of magnetic fields on the rate of phenol biodegradation using immobilized activated sludge. A recirculation flow bioreactor employing immobilized bacterial beads was used with phenol as the substrate to study the biodegradation process. This study was conducted by applying separately the north pole and the south pole magnetic fields to the bioreactor. Rate of dissolved oxygen consumption, phenol concentration and extracellular protein concentration were the parameters monitored during the process. It was observed that by applying a magnetic south pole to the process, biodegradation in the form of biological oxidation was enhanced. A 30% increase in biodegradation rate was obtained by applying a magnetic south pole of strength of 0.45 Tesla to the bioreactor with immobilized microbial beads as compared to the control. Magnetic north pole irradiation inhibited this type of biooxidation. This process has potential for biological treatment of organic wastes.

An experimental bio-column composed of aged refuse was installed around the exhaust pipe as a new way to mitigate methane in refuse landfill. One of the objectives of this work was to assess the effect of aged refuse thickness in bio-column on reducing CH 4 emissions. Over the study period, methane oxidation was observed at various thicknesses, 5 cm (small size), 10 cm (middle size) and 15 cm (large size), representing one to three times of pipeline diameters. The middle and large size both showed over 90% methane conversion, and the highest methane conversion rate of above 95% occurred in the middle-size column cell. Michaelis-Menten equation addressed the methanotrophs diffusion in different layers of the bio-columns. Maximum methanotrophic activity ( V max ) measured at the three thicknesses ranged from 6.4 × 10 −3 to 15.6 × 10 3 units, and the half-saturation value ( K M ) ranged from 0.85% to 1.67%. Both the highest V max and K M were observed at the middle-size of the bio-column, as well as the largest methanotrophs population, suggesting a significant efficiency of methane mitigation happened in the optimum zone with greatest affinity and methanotrophic bacteria activities. Therefore, bio-column is a potential style for methane abatement in landfill, and the aged refuse both naturally formed and artificially placed in the column plays a critical role in CH 4 emission.

The state-of-the-art of investigations in the field of catalysis of biological oxidation of saturated hydrocarbons by molecular oxygen and simulation of this process based on metal complexes is reviewed. The bibliography includes 296 references.

In this work, it has been studied the use of conductive-diamond electrochemical oxidation (CDEO) as a refining technology to assure the quality of the effluents of door manufacturing processes (DMP). To do this, the raw effluents of these factories have been treated by a combination of physicochemical, biological and CDEO treatments. CDEO was found to be a feasible alternative to the refinement of a wooden DMP waste. It can successfully decrease the organic load of the effluents of the biological oxidation with low energy requirements. In addition, in case of incidents in the biological process, CDEO can treat successfully the effluents of the coagulation process. The effluents of the biological treatment have also been treated by CDEO in order to check the possible use of electrochemical technology to increase the biodegradability of the effluents and their possible recycle to the biological treatment. Unfortunately, electrochemical technology was found to be not adequate to increase the biodegradability of the effluents of a biological treatment. The hard oxidation conditions generated during CDEO do not lead to the accumulation of intermediates but to the almost direct formation of carbon dioxide. Lowering the current density or changing the electrodes can not enhance the biodegradability of the effluents of an electrochemical cell.

Characteristics of degradation of blue‐green alga, Microcystis aeruginosa by Mastigophora‐Monas guttula were examined. Monoxenic M. guttula was isolated from sewage in the biological oxidation facility equipped in Kasumigaura Water Works. M.guttula could efficiently degrade viable cells of M. aeruginosa during a short time. The removal of the cells by M. guttula was 90% at 48 hours cultivation. The specific growth rate (μ) and generation time (tg) of M. guttula were 4.1 day−1and 4.0 hour, respectively. While, maximum specific growth rate (μma x) and saturation coefficient (Ks) of the microbe were 4.4 day−1 and 2.4 mg/1 with Lineweaver‐Burk equation. It was clarified that M. guttula could effectively utilize M. aeruginosa as a food for its strong affinity and reactivity.

The removal of hydrogen sulfide (H2S) was investigated in a lab scale biofilter packed with biomedia, encapsulated by sodium alginate and polyvinyl alcohol (PVA). The main H2S oxidation products were SO 4 2 - , SO 3 2 - , S2− and S0. The immobilized cell biofilter required no separate acclimatization period and showed high removal efficiencies (RE) within the first few days of experiments. The removal efficiencies in the biofilter were consistently greater than 99% even when H2S loading was 6 g m−3 h−1. The maximum elimination capacity achieved in this study is 8 g H2S m−3 h−1 at a loading rate of 13 g H2S m−3 h−1. The response of the immobilized cells to fluctuations in inlet concentration and flow rate was determined by subjecting the biofilter to inlet loads of up to 10 g H2S m−3 h−1. The biofilter responded effectively to these shock loading conditions and convalesced rapidly within 4–8 h. Pressure drop values were consistently less throughout the operational period. The results from this study suggest that an immobilized cell biofilter is effective in treating H2S under steady and transient operating conditions.

Acaeruloplasminaemia is characterized by excessive neurovisceral iron accumulation due to mutation of the caeruloplasmin gene. Excess iron functions as a potent catalyst of biological oxidation, and increased iron concentration is associated with the products of lipid peroxidation in the serum and cerebrospinal fluid. We investigated whether the amount of iron accumulated paralleled lipid peroxidation levels in acaeruloplasminaemia tissues, examining brains and visceral organs of two affected patients at autopsy for iron and copper content, and oxysterols, including 7-hydroxycholesterol and 7-ketocholesterol, which are directly produced from cholesterol by active oxygen species. The amount of iron accumulated in various tissues was correlated with the levels of the oxysterols. These findings suggest that lipid peroxidation produced by the intracellular accumulation of iron is involved in the pathogenesis of acaeruloplasminaemia.

In this work the treatment of leachate originating from an old landfill was compared using a variety of methods both singularly and in combination. Aerobic biological treatment gave a COD removal ranging from 32–35%, but it was very effective for BOD and ammonia removal (97% and 99%, respectively). By using chemical oxidation a COD reduction up to 33% was achieved. The application of chemical precipitation gave a COD removal in the range of 36–42%. The combination of biological and chemical oxidation, biological oxidation and chemical precipitation or chemical oxidation and chemical precipitation, led to a COD reduction up to 57%. The best results were obtained when a biological oxidation was applied in two stages combination with chemical oxidation and chemical precipitation reducing COD concentration values up to 87%.

O,S -Dimethyl phosphoramidothiolate, the insecticide methamidophos, is converted oxidatively into a potent anti-cholinesterase agent by the action of m -chloroperbenzoic acid. The active intermediate is not stable enough to be isolated. From some chemical evidence, the sulfoxide, i.e., dimethyl phosphoramidothiolate S -oxide, is most probably the active intermediate. A similar activation may occur by biological oxidation.

The purpose of this study was to address some of these issues by investigation of biological oxidation characteristics of specific coke plant ammonia still effluent. Specific objectives were to det...

The isolation, structure determination, and reactivity of the tricyclic labile hydroperoxides 10 and 2 obtained by dye-sensitized photooxygenation of L-, D-, and DL-tryptophan and Nb-methoxycarbonyltryptophan ester are reported. The tricyclic hydroperoxide 10, under appropriate conditions, was easily convertible to formylkynurenine. Plausible mechanisms for these transformations are discussed.

Data are presented on the removal of soluble organic nitrogen (SON) and soluble chemical oxygen demand (SCOD) by chemical coagulation, activated-carbon adsorption, ion exchange, lime precipitation, chemical oxidation, biological oxidation and various combinations of these processes. This information will enable decision makers to assess the economic impact and technological feasibility of setting limitations on the discharge of organic nitrogen, and will be of use to engineers in designing treatment systems for removal of SON should limitations be imposed. A hypothetical scheme is proposed which operationally fractionates SON and SCOD in a manner defined by the experimental results of the study and by the nature of the processes involved. The scheme divides SON and SCOD into a number of fractions and indicates which are mutually exclusive and which overlap. Such a scheme is helpful in understanding and predicting the behavior of organic contaminants with respect to various treatment processes and fractionates organics.

Ubiquinone-2 (1) was oxidized to 6-[7-carboxy-3-methyl- (2E, 6E)-2, 6-octadienyl]-2, 3-dimethoxy-5-methyl-1, 4-benzoquinone (2) and 6-[6, 7-dihydroxy-3, 7-dimethyl- (E)-2-octenyl]-2, 3-dimethoxy-5-methyl-1, 4-benzoquinone (3) by the 6000×g supernatant of guinea-pig liver homogenate in the presence of nicotinamide-adenine dinucleotide (NAD)- and dihydronicotinamideadenine dinucleotide phosphate (NADPH)-generating systems.

Oxidation of allitol by Acetomonas oxydans yields l -allulose ( l -ribo-hexulose) in accordance with the Bertrand-Hudson rule.

A simple method is described for the separation and identification of steroids produced during the fermentative oxidation of progesterone by Fusarium spp. The steroid products are separated by thin-layer chromatography on silica-gel G with ethylacetate-cyclohexane (2∶1) as solvent and characterized by colour reaction with 50% sulphuric acid and UV fluorescence. The entire procedure can be completed within one hour and thus could be useful in the control of biological oxidation of progesterone.

1. Heterocyclic aromatic amines occur in many drugs and foreign compounds, as well as products of intermediary metabolism.2. Heterocyclic aromatic amine oxides occur naturally in plants, fungi and other micro-organisms but are rare in mammalian systems.3. Very few xenobiotics have been reported to form heterocyclic aromatic amine oxides and the mechanism of their formation is not at present understood.4. The reduction of heterocyclic aromatic amine oxides to the parent amine occurs with many biological systems.

Conditions have been established for the oxidation of naphthalene by a pseudomonad based on the yields of ether extractable substances. Vigorous aeration yielded approximately three times the product obtained from unaerated controls. Oxidations with media adjusted initially to pH 8 gave higher yields than those adjusted to lower pH levels. Calcium and copper appeared to be necessary for maximum yields. Under the conditions described, the non-naphthalenic ether extractable substances amounted to as much as 29% of the original 1% naphthalene. Purification and analysis of the crude extract showed that it consisted largely of salicylic acid. Some properties of the remaining material are described.

Eburicodiol and eburical as well as previously reported eburicol have been isolated from the neutral chloroform extracts of Formes officinalis . A triterpenic acid, identified as sulphurenic acid, has also been isolated.