Simultaneous Aeration Research Articles

Simultaneous Aeration and Neutralization of Mine Water: An Apparently Forgotten Discovery

Simultaneous Aeration and Neutralization of Mine Water: An Apparently Forgotten Discovery

Factors Affecting Spore Formation of Carrot Leaf Blight Caused by Alternaria dauci In Vitro

In order to examine the pathogenicity of <i>Alternaria dauci</i>, the causal agent of carrot leaf blight, it is necessary to standardize sporulation conditions to ensure the optimal quantity and quality of spore inoculum. Therefore, in this study, the effects of the growth medium, aeration treatment, and UV treatment with 12-hr photoperiod on the sporulation of <i>A. dauci</i> KACC42997 were investigated. <i>A. dauci</i> KACC42997 was pre-cultured for 7 days in a potato dextrose agar medium at 25oC in the dark condition. When the pre-culture, after removing aerial mycelia, was re-incubated for 5 days, with simultaneous aeration treatment and 12-hr cycle UV treatment at 20oC, the largest number of spores was produced. One hundred seventy isolates of <i>A. dauci</i> were isolated from major carrot growing regions such as Pyeongchang, Gumi and Jeju and tested for sporulation under the conditions established in this study. Except for 20 strains, all strains produced spores. Statistically significant differences in the extent of sporulation were found among local populations of <i>A. dauci</i> isolates, but no difference was observed in their pathogenicity on carrots.

Methods for removing reduced sulfur compounds from groundwater

Reduced sulfur compounds contained in natural waters adversely affect human health in wastewater, cause corrosion of collector materials and structures, and inhibit biological treatment processes. The methods to reduce the reduced sulfur compounds concentration in natural and waste waters are quite well known, however, in each case, in accordance with the requirements for the quality of treatment and the initial concentration of reduced sulfur compounds, it is necessary to adapt the methods used. This article presents the results of studies on the removal of reduced sulfur compounds from groundwater. The results of the reduced sulfur compounds oxidation method with hydrogen peroxide to sulfates with aeration and without aeration of the treated water are presented, as well as the results of studies on colloidal sulfur coagulation resulting from the incomplete oxidation of the reduced sulfur compounds. The expediency of using the reduced sulfur compounds of hydrogen peroxide with simultaneous aeration of the treated water as an oxidizing agent is shown. It was established that the contact duration of the treated water containing the reduced sulfur compound with hydrogen peroxide, both with and without simultaneous aeration, should be at least 30 minutes. The results of experiments on the colloidal sulfur coagulation are also presented, indicating that the use of sodium hydro-aluminate in proportion to aluminum sulfate, which ensures the ratio [OH+]: [Al3+] = 0,5, allows not only to achieve results in water purification with bringing the quality to the standards for drinking water, but also to reduce the coagulant dose in its active part by 30%, compared to other options. It has been analytically established that when using aluminum oxy sulfates or oxy chlorides for coagulation of colloidal sulfur, it is advisable to use the low-base coagulants.

Fermentation of coffee pulp using indigenous lactic acid bacteria with simultaneous aeration to produce cascara with a high antioxidant activity

Coffee pulp which is a by-product of coffee production contains considerable amounts of phenolic compounds that can be valorised to produce cascara as an antioxidant beverage. The fermentation and drying conditions of the coffee pulp have a great influence on the bioactive compounds in the cascara. This study aimed to investigate the effect of natural fermentation with simultaneous aeration on the phenolic content and antioxidant activity of cascara. A systematic study was carried out using a response surface methodology with a face-centered central composite design to determine the effect of fermentation time (0–8 h) and temperature (27–37 °C) on the number of bacteria in the coffee pulp after natural fermentation with simultaneous aeration (an air flowrate of 4 m/s) as well as phenolic content and antioxidant activity of cascara. The experimental dataset was modelled with an empirical model using multi-variable non-linear regression. A good agreement between model and experimental data was obtained. At the optimum conditions (4.2 h, 31.8 °C), the phenolic content was 6.72% whereas the antioxidant activity was 27.6%. Indigenous lactic acid bacteria were also isolated from the coffee pulp and determined as Leuconostoc pseudomesenteroides. The isolated bacteria can be used as a starter for controlled fermentation of coffee pulp as it increased the antioxidant activity up to 15% higher than the antioxidant activity of cascara obtained at the optimum conditions for natural fermentation with simultaneous aeration and 30% higher from the fresh coffee pulp.

Effect of Electrode Material and Hydrodynamics on the Produced Current in Double Chamber Microbial Fuel Cells.

In recent decades, there has been huge interest in exploring cost-effective and sustainable ways for energy production using fuel cells. In this study, different electrode materials, namely, nickel, stainless steel, brass, and graphite were used to investigate the energy production in double chamber microbial fuel cells. Yeast microorganisms (MOs) (Saccharomyces cerevisiae) were used at different concentrations for electricity production under different operating conditions with glucose as a substrate. The produced current and potential of the electrode were measured for ranges of operating conditions such as MO concentration (1–8 g/L), flow velocity (0–600 rpm), and aeration of the catholyte. It was found that there was a different performance exhibited by each electrode material, with nickel and graphite giving the highest efficiency. Increasing the flow velocity and aeration in the cathode compartment led to increasing the produced current while the flow and aeration in the anode compartment had a negative effect on the produced current. Simultaneous aeration and agitation gave high produced current values, while high agitation with aeration reduced the efficacy. The increased concentration of substrate glucose showed different influences on the produced current depending on electrode materials.

Biosorption of cadmium and copper ions from industrial wastewaters by waste activated sludge

ABSTRACT In this study, the removal of cadmium and copper ions from aqueous solutions was investigated by waste activated sludge (WAS) under three conditions: (1) without any aeration and feeding, (2) by aeration without feeding and (3) by simultaneous aeration and feeding. The initial concentration, temperature, contact time, aeration and feeding had influence in Cd2+ and Cu2+ removal. The maximum removal of Cd2+ and Cu2+ was obtained with an initial concentration of 5 mg/L of each heavy metal that occurred in the third step (aeration and feeding of activated sludge) with removal efficiency of 75.45% and 76.91% for Cd2+ and Cu2+, respectively. This study showed that WAS has a high biosorption removal capacity for Cd2+ and Cu2+ and can be used as an effective biosorbent for the removal of cadmium and copper and/or other types of heavy metals from industrial wastewaters.

Evaluating Photo-Catalytic Application of TiO2 Nano Particles Augmented With H2O2 for Mineralization of Pharmaceutical Effluent

Interest in the photocatalytic oxidation of non biodegradable organics from contaminated wastewater is growing rapidly. The photocatalytic activity of TiO2 nano particles synthesized via Sol-Gel method for the degradation of pharmaceutical effluent under UV light was discussed in this study. The TiO2 nano particles were characterized by X-Ray Diffraction (XRD) to determine size, Morphology Index, Specific Surface area and surface to volume ratio. The XRD results revealed that the TiO2 was composed of average size 12.96 nm. The treatment scheme involves charcoal adsorption and filtration prior to photocatalytic oxidation with TiO2 nano particles, H2O2 addition and Simultaneous aeration. Effect of various parameters like pH, Catalyst dosage and H2O2 concentration were studied to determine optimum conditions. Keywords: TiO2 nano particles; X-ray Diffraction; Adsorption; Sol-Gel method; Photo-Catalytic Oxidation

Selenite removal from groundwater by zero-valent iron (ZVI) in combination with oxidants

We recently demonstrated common oxidants simply coupled with ZVI to continuously drive the accelerated Fe0 corrosion and hence achieve fast and very efficient removal of heavy metals and metalloids from groundwater. In this study, we aimed first to answer a basic question of the oxidant dosage theoretically required to sequester a certain amount of selenite. The specific ratio of oxidant dosage to Se(IV) removal, which reflected the theoretically minimal oxidant dosage required to sequester one mole of Se(IV), was almost independent of the initial Se(IV) concentration but significantly affected by the difference in oxidant species. To sequester one mole of Se(IV), the minimum dosage of the required oxidant was calculated to be 3.94–4.09 for NaClO, 3.90–4.33 for H2O2, and 3.29–3.54 for KMnO4, respectively. Simultaneous aeration increased the removal efficiency of Se(IV) and substantially reduced the required dosage of oxidants. To form a strong contrast with very limited Se(IV) removal by ZVI alone, the coupling of NaClO and H2O2 into the ZVI system remarkably enhanced the performance of Se(IV) removal during the long term fixed-bed experiments with a real groundwater background. The ZVI columns coupled by NaClO and H2O2 steadily treated 10,000 volumes (BV) of real groundwater. X-ray adsorption near edge structure (XANES) demonstrated that more than 85% of the selenium was reduced to Se0 and Se2−, with Se0 as the dominant selenium species sequestered in the solid phase. Synchrotron-based scanning transmission soft X-ray microscopy (STXM) explicitly revealed the ubiquitous spatial distribution of selenium in the corrosion products and hence demonstrated a high accessibility of these corrosion products to selenite.

A Unique Autothermal Thermophilic Aerobic Digestion Process Showing a Dynamic Transition of Physicochemical and Bacterial Characteristics from the Mesophilic to the Thermophilic Phase.

A unique autothermal thermophilic aerobic digestion (ATAD) process has been used to convert human excreta to liquid fertilizer in Japan. This study investigated the changes in physicochemical and bacterial community characteristics during the full-scale ATAD process operated for approximately 3 weeks in 2 different years. After initiating simultaneous aeration and mixing using an air-inducing circulator (aerator), the temperature autothermally increased rapidly in the first 1 to 2 days with exhaustive oxygen consumption, leading to a drastic decrease and gradual increase in oxidation-reduction potential in the first 2 days, reached >50°C in the middle 4 to 6 days, and remained steady in the final phase. Volatile fatty acids were rapidly consumed and diminished in the first 2 days, whereas the ammonia nitrogen concentration was relatively stable during the process, despite a gradual pH increase to 9.3. Principal-coordinate analysis of 16S rRNA gene amplicons using next-generation sequencing divided the bacterial community structures into distinct clusters corresponding to three phases, and they were similar in the final phase in both years despite different transitions in the middle phase. The predominant phyla (closest species, dominancy) in the initial, middle, and final phases were Proteobacteria (Arcobacter trophiarum, 19 to 43%; Acinetobacter towneri, 6.3 to 30%), Bacteroidetes (Moheibacter sediminis, 43 to 54%), and Firmicutes (Thermaerobacter composti, 11 to 28%; Heliorestis baculata, 2.1 to 16%), respectively. Two predominant operational taxonomic units (OTUs) in the final phase showed very low similarities to the closest species, indicating that the process is unique compared with previously published ones. This unique process with three distinctive phases would be caused by the aerator with complete aeration.IMPORTANCE Although the autothermal thermophilic aerobic digestion (ATAD) process has several advantages, such as a high degradation capacity, a short treatment period, and inactivation of pathogens, one of the factors limiting its broad application is the high electric power consumption for aerators with a full-scale bioreactor. We elucidated the dynamics of the bacterial community structures, as well as the physicochemical characteristics, in the ATAD process with a full-scale bioreactor from human excreta for 3 weeks. Our results indicated that this unique process can be divided into three distinguishable phases by an aerator with complete aeration and showed a possibility of shortening the digestion period to approximately 10 days. This research not only helps to identify which bacteria play significant roles and how the process can be improved and controlled but also demonstrates an efficient ATAD process with less electric power consumption for worldwide application.

Porosimetric, Thermal and Strength Tests of Aerated and Nonaerated Concretes

The paper presents the results of porosimetry tests of lightweight concretes, obtained with three research methods. Impact of different porosity structures on the basic thermal and strength properties was also evaluated. Tests were performed, using the pressure gauge method on fresh concrete mixes, as well as using the mercury porosimetry test and optic RapidAir method on specimens prepared from mature composites. The study was conducted on lightweight concretes, based on expanded clay aggregate and fly ash aggregate, in two variants: with non-aerated and aerated cement matrix. In addition, two reference concretes, based on normal aggregate, were prepared, also in two variants of matrix aeration. Changes in thermal conductivity λ and volumetric specific heat cv throughout the first three months of curing of the concretes were examined. Additionally, tests for compressive strength on cubic samples were performed during the first three months of curing. It was found that the pressure gauge method, performed on a fresh mix, gave lowered values of porosity, compared to the other methods. The mercury porosity tests showed high sensitivity in evaluation of pores smaller than 30μm. Unfortunately, this technique is not suitable for analysing pores greater than 300μm. On the other hand, the optical method proves good in evaluation of large pores, greater than 300μm. The paper also presents results of correlation of individual methods of porosity testing. A consolidated graph of the pore structure, derived from both mercury and optical methods, was presented, too. For the all of six tested concretes, differential graphs of porosity, prepared with both methods, show a very broad convergence. The thermal test results indicate usefulness of aeration of the cement matrix of the composites based on lightweight aggregates for the further reduction of the thermal conductivity coefficient λ of the materials. The lowest values of the λ coefficient were obtained for the aerated concretes based of fly ash aggregate. A diminishing influence of aeration on the volumetric heat capacity cv is clearly seen. Simultaneous aeration of the matrix and use of lightweight aggregates brought about also a significant decrease in the average compressive strength fcm of the tested composites.

Enrichment of Parachlorella kessleri biomass with bioproducts: oil and protein by utilization of beet molasses

The aim of this study was to determine the suitability of beet molasses, an agro-industrial by-product, as an alternative culture medium component for photoheterotrophic and mixotrophic cultivation of Parachlorella kessleri. Application of beet molasses improved microalgal cell growth and modified the biochemical composition of P. kessleri biomass. During the addition of molasses to culture media with simultaneous aeration, the maximum biomass productivity, oil and protein productivity, and calorific value were 0.42 g L−1 day−1, 112.56 and 244.95 mg L−1 day−1, and 22.1 MJ kg−1, respectively. Under these conditions, the total content of polyunsaturated C16-C18 fatty acids decreased, which was suitable for application in biodiesel. Besides oils and carbohydrates, P. kessleri had an ability to synthesize significant amounts of proteins, especially during molasses utilization. This provides a possibility of a wide range of non-fuel applications of P. kessleri biomass.

Development of a CFD model for the simulation of a novel multiphase counter-current loop reactor

Many bio-based processes exhibit low yields resulting from inhibitions. This innovative concept for a multiphase-loop reactor can overcome these limitations with a simultaneous aeration and extraction of valuable compounds in one unit operation.One dispersed phase is used to initiate a loop flow in the reactor while the other phase is dispersed in the downcomer. Therefore, the second dispersed phase rises in the counter-current.The multiphase flow was simulated using a 2D axis-symmetric Euler-Euler approach in CFD. Besides friction force and gravitation the turbulent dispersion force was considered applying the standard k-ε turbulence model. The simulation of the reactor was validated in pilot-plant experiments. A comparison of the holdup of the dispersed phases and a visual evaluation of the flow field presented very good agreements between the experiments and simulations. Water, Shellsol T and synthetic air were used in the experiments. An improvement of the reactor design was possible based on additional simulation studies.

Escherichia coli inactivation by pressurized CO2 treatment methods at room temperature: Critical issues

This study aims to increase the inactivation efficiency of CO2 against Escherichia coli under mild conditions to facilitate the application of pressurized CO2 technology in water disinfection. Based on an aerating-cycling apparatus, three different treatment methods (continuous aeration, continuous reflux, and simultaneous aeration and reflux) were compared for the same temperature, pressure (0.3–0.7MPa), initial concentration, and exposure time (25min). The simultaneous aeration and reflux treatment (combined method) was shown to be the best method under optimum conditions, which were determined to be 0.7MPa, room temperature, and an exposure time of 10min. This treatment achieved 5.1-log reduction after 25min of treatment at the pressure of 0.3MPa and 5.73-log reduction after 10min at 0.7MPa. Log reductions of 4.4 and 5.0 occurred at the end of continuous aeration and continuous reflux treatments at 0.7MPa, respectively. Scanning electron microscopy (SEM) images suggested that cells were ruptured after the simultaneous aeration and reflux treatment and the continuous reflux treatment. The increase of the solubilization rate of CO2 due to intense hydraulic conditions led to a rapid inactivation effect. It was found that the reduction of intracellular pH caused by CO2 led to a more lethal bactericidal effect.

Simulated solar-light induced photoelectrocatalytic degradation of bisphenol-A using Fe3+-doped TiO2 nanotube arrays as a photoanode with simultaneous aeration

Abstract The aeration assisted photoelectrocatalytic (“PEC + Aeration”) degradation of bisphenol A (BPA), a representative endocrine-disrupting chemical, was studied on Fe3+-doped TiO2 nanotube arrays (Fe/TNAs) under simulative solar-light irradiation. Fe/TNAs were prepared by anodization and subsequent dip-coating and characterized by field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction and UV–Vis reflectance spectroscopy. Results showed that higher efficiencies of BPA degradation and mineralization could be achieved from “PEC + Aeration” process than those from conventional PEC process. Effects of current density, initial pH, initial BPA concentration and airflow rate were investigated. Moreover, active species were identified to reveal the PEC degradation mechanism of BPA. H2O2, OH and O2 − are the main reactive species responsible for BPA degradation and aeration performs in BPA elimination. Results reveal that the proposed process is an efficient method for BPA degradation and mineralization.

New controlled release material: aerated egg white gels induced by calcium ions

The aim of the research was to use low-mineral egg white albumin isolate to obtain aerated calcium ion-induced gels and to investigate their aptitude as matrices for active ingredients release. Aerated gels were prepared by adding calcium ions to pre-heated protein dispersions with simultaneous aeration. 20 mM calcium concentration was an optimal concentration at which the maximum viscosity and hardness of the gels were found. For higher concentrations of calcium ions (25–30 mM), aerated gels were characterized by lower values of the moduli and tangent of the phase angle was larger for aerated gels which indicated more viscous character than that of non-aerated gels. Increased ions concentration causes higher aggregation of protein matrix and less smooth microstructure of the interface between the gel and air. An increase in calcium concentration from 5 to 30 mM caused an increase in an average bubble size. The release of calcium ions from aerated gels was measured in an artificial stomach. It occurred by Fickian diffusion through the swelling matrix and it was faster for the gels with higher concentration of calcium. An increase in calcium concentration caused an increase in surface roughness of the aerated gels. There were linear correlations between the quadratic mean of the surface roughness and “n” coefficient from the Ritger and Peppas equation and between the maximum roughness size and “n”. The increased calcium concentration made the gel microstructure more particulate and the surface rougher, which enabled faster proteolysis of the gel in an artificial stomach and faster diffusion of calcium ions.

Electrodialytic upgrading of three different municipal solid waste incineration residue types with focus on Cr, Pb, Zn, Mn, Mo, Sb, Se, V, Cl and SO4

Handling of air pollution control (APC) residues from municipal solid waste incineration (MSWI) is a challenge due to its toxicity and high leaching of toxic elements and salts. Electrodialysis (ED) of the material has shown potential for reduction of leaching of toxic elements and salts to produce a material feasible for substitution of cement in mortar. In this work results of 23 pilot-scale experiments (5–8kg APC residue each) in electrodialysis stack designed to investigate the leaching properties as a function of time and current density for APC residue from semi-dry and wet flue-gas cleaning systems, as well as MSWI fly ash without flue-gas cleaning products are reported. Significant leaching reduction of the critical elements Pb, Zn and Cl was obtained. The final leaching, however, depended mostly on the initial leaching, thus as leaching from fly ash and residue of wet flue-gas cleaning was lower before treatment compared to residues from semidry flue-gas cleaning, both Pb and Zn leaching could be reduced to lower levels in those materials, and they therefore appear more suitable for use in construction materials. The leaching reduction of Zn and to some degree Pb decreased with longer retention times and higher current densities. Cr and SO4 leaching increased during ED treatment, with lower increase at higher current. Washing or carbonation in combination with ED significantly reduced leaching of Pb and Zn from semidry residue. An indication of a similar effect to carbonation by simultaneous aeration with ED was observed and should be investigated further. While Mn and Mo leaching did not, Se, V and Sb leaching exceeded threshold values in semidry residue. The leaching of V seemed to increase while Se and Sb remained more or less constant during ED treatment.

Evaluation of Sequential Batch Reactor (SBR) Cycle Design to Observe the Advantages of Selector Phase Biology to Achieve Maximum Nutrient Removal

Pilot plant studies of sequential batch reactor (SBR) cycles revealed the role of selector phase biology (SPB) involved in COD removal, nitrification, denitrification and total phosphate removal. The phases namely anoxic, anaerobic and aerobic in single tank reactor design of SBR were showed effective biological nutrient removal (BNR) > 90% on average in 4 h designed cycle time with 12 h of hydraulic retention time (HRT). The phases were 2 h fill which includes 1 h simultaneous fill and aeration, 1 h settle and 1 h decant. This cycle design found effective to create selective environment for microbes to carry biological organic and nutrient removal reactions with improvement in sludge volume index (SVI).

Evaluation and prediction of membrane fouling in a submerged membrane bioreactor with simultaneous upward and downward aeration using artificial neural network-genetic algorithm

This paper describes the effect of simultaneous upward and downward aeration on the membrane fouling and process performances of a submerged membrane bioreactor. Trans-membrane pressure (TMP) and membrane permeability (Perm) were simulated using multi-layer perceptron and radial basis function artificial neural networks (MLPANN and RBFANN). Genetic algorithm (GA) was utilized in order to optimize the weights and thresholds of the models. The results indicated that the simultaneous aeration does not significantly improve the removal efficiency of contaminants. The removal efficiencies of BOD, COD, total nitrogen, NH4+−N and TSS were 97.5%, 97%, 94.6%, 96% and 98%, respectively. It was observed that the TMP increases and the Perm decreases as operational time increases. The TMP increasing rate (dTMP/dt) and the Perm decreasing rate (dPerm/dt) for the upward aeration were 2.13 and 2.66 times higher than that of simultaneous aeration, respectively. The training procedures of TMP and Perm models were successful for both RBFANN and MLPANN. The train and test models by MLPANN and RBFANN showed an almost perfect match between the experimental and the simulated values of TMP and Perm. It was illustrated that the GA-optimized ANN predicts TMP and permeability more accurately than a network with a trial-and-error approach calibration.

Ultrasonic removal of pyridine from wastewater: optimization of the operating conditions

In this study, a fundamental research had been carried out to explore the removal of pyridine in wastewater by ultrasound radiation. The effects of initial pyridine concentration, radiation time, pH, aeration, and the reaction temperature on the pyridine removal efficiency were investigated. The removal rates of pyridine at 180 min sonication time were found to decrease from 53 to 15 % with increasing the initial concentration from 10 to 100 mg/L. However, the total amount of pyridine degraded after 60 min at 100 mg/L was as much as three times larger than that degraded at 10 mg/L. The optimal pH was found to be 9 which resulted in 25 % pyridine removal after 180 min ultrasound radiation. By observing the change of pH value with the sonication time up to 60 min, it was observed that, pH of the sonicated pyridine aqueous mixture has decreased from 9.2 to 6.2 during the irradiation. The decrease in the pH may be attributed due to the formation of peroxy radicals in the solution and subsequently formation of oxygen free radicals. The simultaneous aeration could improve pyridine removal efficiency of ultrasound irradiation by 24 %. With increasing media temperatures, the removal efficiencies of pyridine increased in the temperature range in this study. In the end, it could be proposed that ultrasound radiation was an effective method for the removal of pyridine from wastewater.

Physical and oxidative removal of organics during Fenton treatment of mature municipal landfill leachate

Municipal landfill leachate, especially mature leachate, may disrupt the performance of moderately-sized municipal activated sludge wastewater treatment plants, and likewise tend to be recalcitrant to biological pretreatment. Recently, Fenton methods have been investigated for chemical treatment or pre-treatment of mature leachate. In this paper, the results of laboratory tests to determine the roles of oxidation and coagulation in reducing the organic content of mature leachate during Fenton treatment are presented. The efficiencies of chemical oxygen demand (COD) oxidation and coagulation were tested, and the ratio of COD removal by oxidation to that by coagulation was assessed, under various operating conditions. Low initial pH, appropriate relative and absolute Fenton reagent dosages, aeration, and stepwise addition of reagents increased COD removal by oxidation and the importance of oxidation relative to coagulation. Simultaneous aeration and stepwise reagent addition allowed comparable treatment without initial acidification pH, due to the generation of acidic organic intermediates and the continuous input of CO 2. On the other hand, high COD oxidation efficiency and low ferrous dosage inhibited COD removal by coagulation. At significantly high oxidation efficiency, overall COD reduction decrease slightly due to low coagulation efficiency. Under the most favorable conditions (initial pH 3, molar ratio [H 2O 2]/[Fe 2+] = 3, [H 2O 2] = 240 mM, and six dosing steps), 61% of the initial COD was removed, and the ratio of COD removal oxidation to coagulation was 0.75. Results highlighted the synergistic roles of oxidation and coagulation in Fenton treatment of mature leachate, and the role of oxidation in controlling the efficiency of removal of COD by coagulation.