Cylindrical Reactor Research Articles

Measurement of radiative gas and particle emissions in biomass flames

Radiation is the dominant mode of heat transfer near the burner of coal and biomass-fired boilers. Predicting and measuring heat transfer is critical to the design and operation of new boiler concepts. The individual contributions of gas and particle phases are dependent on gas and particle concentration, particle size, and gas and particle temperature which vary with location relative to the flame. A method for measuring the contributions of both gas and particle radiation capable of being applied in harsh high temperature and pressure environments has been demonstrated using emission from particles and water vapor using an optical fiber probe transmitting a signal to a Fourier Transform Infrared (FTIR) spectrometer. The method was demonstrated in four environments of varying gas and particle loading using natural gas and pulverized wood flames in a down-fired 130 kWth cylindrical reactor. The method generates a gas and particle temperature, gas concentrations (H2O and CO2), total gas and particle intensities, and gas and particle total effective emissivity from line-of-sight emission measurements. For the conditions measured, downstream of the luminous flame zone, water vapor and CO2 radiation were the dominant modes of heat transfer (effective emissivity 0.13–0.19) with particles making a minor contribution (effective emissivity 0.01–0.02). Within a lean natural gas flame, soot emission was low (effective emissivity 0.02) compared to gas (0.14) but within a luminous flame of burning wood particles (500 µm mean diameter) the particles (soot and burning wood) produced a higher effective emissivity (0.17) than the gas (0.12). The measurement technique was therefore found to be effective for several types of combustion environments.

Isotropy of sphere packings in a cylindrical confinement

The underlying structure in apparently “randomly-packed” packed beds is a subject of topical interest, particularly in the context of deep processing, such as deep hydrodesulfurization. Packed beds typically exhibit “packing defects”; for instance, surface abnormalities such as a slope, a bump (convex surface), a hollow (concave surface), or even donut-shaped rings on the top surface of a packed bed. While these defects are observed at the top free surface of the packed bed, there are concerns that this may continue to propagate down the height, and in turn, cause local flow variations and differential wetting, which affect reactor performance, catalyst life, and formation of local hot spots. These defects come because of different protocols that are followed for packing particles, which are mainly developed out of empiricism since the physics of granular flow in confinements (such as a vertical cylindrical reactor vessel) is as yet not well understood. Earlier work on the structure of packed beds relates only to the spatial distribution of voidage, and not on how the particles are arranged with respect to each other in the reactor. This work is an attempt in that direction. We present first the use of Sequential Ballistic Deposition (SBD) algorithm to model the packing process itself, i.e., how the method of packing (modeled in this work through some simple protocols) yields a certain structure of the bed. Second, we show the use of Voronoi tessellation and the use of two of the Minkowski tensors (the Volume Moment Tensor and the Surface Orientation Tensor) to characterize the packed bed structure. Further analysis is presented which shows that we are able to fingerprint the packed bed formed through different packing methods, hence creating a link between the two.

Composting of chicken manure with a mixture of sawdust and wood shavings under forced aeration in a closed reactor system

PurposeThis study aimed to achieve successful composting and aeration rate and to optimize the carbon:nitrogen (C:N) ratio to provide favourable conditions for the process. In the current experiment, investigation were made on variations in physico–chemical properties, i.e., temperature, ammonia and carbon dioxide emissions, pH, electrical conductivity (EC), organic matter (OM) and seed germination index (GI%) of composting chicken manure mixed with sawdust and wood shavings under different aeration rates in a closed reactor system.MethodsThree cylindrical reactors (total volume, 60 L) were used with three aeration rates of 0.25, 0.50 and 0.75 L min−1 kg−1 OM. The air was dispensed from the bottom of an air compressor. The ambient and compost temperature were monitored thrice daily over 30 days of composting.ResultsThe highest temperatures were 56.9, 55.8 and 48.1 °C, with 0.25, 0.50 and 0.75 L min−1 kg−1 OM aeration rates, respectively. At the end of composting, lowest ammonia and carbon dioxide emissions were observed with 0.25 L min−1 kg−1 OM aeration, indicating that this compost was more stable than other composts. The lowest GI was recorded on day 30 with 0.75 L min−1 kg−1 OM aeration, indicating severe phytotoxicity in the substrate. Maximum OM degradation occurred with 0.25 L min−1 kg−1 OM aeration.ConclusionThis study, therefore, suggested that 0.25 L min−1 kg−1 OM aeration in the composing of the chicken manure mixed with sawdust and wood shavings in closed a reactor system provided the most favourable conditions for maturation.

Polistirenin Süspansiyon Polimerizasyonuyla Üretiminde Tanecik Boyutu Dağılımının Reaktör Geometrisi ve Karıştırma Koşulları ile İlişkisi

The relation between the reactor geometry and agitation conditions on particle size distribution for suspension polymerization of polystyrene was analyzed. The reactor geometries were selected as cylindrical and spherical, respectively. Mechanical agitation was provided via double-impeller Marine type propeller at 1600 rpm and 2000 rpm. The diameters of the reactors were selected approximately the same for cylindrical and spherical reactors in order to keep effective mixing area similar in both geometries. All experiments were conducted around 8 hours to complete the polymerization reaction. Particle size distribution analyses showed that at faster agitation conditions in cylindrical reactor narrower and smaller particles are obtained as expected. On the other hand, in spherical reactor, vortex formation and non-uniform particle size distribution were observed at faster agitation. Interestingly, when agitation speed was decreased in spherical reactor, quite narrower and smaller particle size distributions with respect to cylindrical reactor were obtained. However, the number and average molecular weight analyses suggested that the particles obtained from spherical reactor has a lower molecular weight distribution than particles from cylindrical reactor. This was attributed to the decrease in effective mixing area due to the non-homogenous changes of the distance between reactor walls and impellers throughout the spherical reactor. The geometry change to spherical geometry obviously causes diminishing in mass transfer of initiators and suspension stabilizers so that a shortening of polymer chains lead to a slight increase in polydispersity index. 

Optimizing Plastic Waste into Bio Crude Fuel Oil using Pyrolysis Induction Thermal System for Energy Security in Indonesia through Analysis of R&D Efficiency: DEA Approach

Indonesia is still far from having an ideal future energy security, which is indicated by energy inefficiency. In fact, the dependency on fossil energy became a barrier to optimize the energy sector. Therefore, to achieve energy security, Indonesia should manage its energy resources strategically. As a solution, it can be solved by utilizing plastic waste as a source of alternative fuel (pyrognate) through pyrolysis treatment. Since plastics synthesized from non-renewable sources, they contributed to great environmental problems. The last research of plastic waste into fuel using element systems which had not reached the optimum temperature for cracking, could not produce more optimal component of distillation fraction, also the electrical power consumption was higher. The approach of this research used mix method analysis to measure the utilization of the plastic waste into fuel oil pyrolysis with the design of a cracking reactor prototype using induction heating technology. The LDPE which has been used in this paper is 0.5 kg, also the reactor which used is made by a stainless steel cylindrical reactor with the diameter of 3.5 inches and the height of 20 cm. It is acceptable because induction heating coils are simple installed at the periphery of the reactor body, the reactor body is heated by the direct induced heat. Subsequently, it heats up the plastic waste very fast at high pyrolysis temperature (400-500oC) and that is easily controlled to increase more fuel oil pyrolysis products (gasoline, kerosene and solar fraction) in a shorter time. Furthermore, the R&D efficiency results showed that the up and down pattern used in its score. It shows in the increasing of R&D efficiency start from 2009 with 0.891 and ended in escalated point with 1.00 efficiency score in 2016. The result showed that it has high energy efficiency due to fast start-up in the process causing low equipment cost (affordability), precision, and repeatability. With the right resolve, Indonesia will emerge to be stronger and more defensible in the realm of energy.

Performance of Helical Ribbon and Screw Impellers for Mixing Viscous Fluids in Cylindrical Reactors

The present paper deals with the mixing of a highly viscous fluid by close-clearance impellers in cylindrical vessels. The study is performed via numerical simulations. Calculations are achieved by the discretization of continuity and momentum equations with the finite volume method. The effect of blade diameter and its shape on the well-stirred region size and the power consumption is investigated. For highly viscous fluids, the obtained results suggest the use of impellers rotating at low Reynolds number, and having a blade with the same shape of the tank to ensure mixing near the vessel base. A comparison is made between the performance of a simple helical ribbon (HR), a simple small screw (SS), helical ribbon-small screw (HR-SS) and a large screw (LS) impeller. The predicted results allow the following classification of impellers studied, based on less power requirements and small size of well-agitated region: SS < HR < HR-SS < LS.

Sonochemical coupled synthesis of Cr-TiO2 supported on Fe3O4 structures and chemical simulation of the degradation mechanism of Malachite Green dye

Cr-TiO2 supported on Fe3O4 material was synthesized using a sonochemical method. By TEM images it was possible to observe cubic morphologies and by XRD and Raman spectroscopy the anatase phase was evaluated, showing that no subsequent thermal treatment was necessary. XPS analysis shows a decrease in the intensity of the Fe3O4 signals when the TiO2 is added to create the material discussed in this paper. Also, by this technique, it was possible to confirm the presence of Cr over the doped materials. In the photocatalysis test. 100% of color removal of the Malachite Green dye (10 mg L−1) was achieved after 300 min of reaction time under solar radiation in a cylindrical reactor with constant bubbling, and only 60% of TOC removal was reached. Using the Time Dependent – Density Functional Theory (TD-DFT) model, was possible to predict the by-products of the photocatalytic reaction of the Malachite Green dye, such as the leuco carbinol Malachite Green, 4-(dimethylamino) benzophenone and 4-[[4-(dimethylamino) phenyl] methyl]-N,N-dimethylaniline Malachite and it its compared with the experimental UV–vis spectra.

Hormones removal from municipal wastewater using ultrasound

Estrogens are one of the micro-pollutants in the wastewater which have detrimental effects on water living organisms. The aim of this study was to evaluate the efficiency of ultrasound to reduce the estrogen (E1) and 17 beta-estradiol (E2) from municipal wastewater. Hence, a cylindrical batch reactor was designed. The effects of powers, frequency, exposure time and pH on reduction efficiency were investigated. The residual concentration of E1 and E2 hormones was measured in reactor effluent by electrochemiluminescence (ECL) method. The results showed that ultrasound removed 85–96% of both E1 and E2 hormones after 45 min while other parameters changes in the range of their operations. Also, the frequency and power of ultrasound had a significant effect on reduction efficiency of hormones while the exposure had no significant effect. Furthermore, the interaction of power and frequency reduced their efficacy to 64.3% (Pvalue = 0.005). The result also indicated that the ultrasound waves have high ability to reduce Steroid hormones from municipal wastewater. The proposed method can be considered as one of the significant strategies for reduction or destruction of hormones from wastewater due to the non-generation of dangerous by-products and the low energy consumption.

Local mass-transfer study in a decaying swirling flow electrochemical reactor under single-phase and two-phase (gas-liquid) flow

Mass transfer was studied at the external electrode of a cylindrical electrochemical reactor with decaying swirling flow using a single phase electrolyte and also a dispersion of a gas phase in the solution. The local mass-transfer coefficients were measured with a segmented cathode using the reduction of ferricyanide as test reaction. Two strategies were used to introduce the gas phase. In the first case the gas was fed by three holes symmetrically drilled at the bottom of the central anode tube and in the second one by means of a tee fitting at the reactor inlet. The best performance was obtained with the single phase electrolyte giving 0.78 as the exponent of the Reynolds number and the mass-transfer distribution along the reactor length is more uniform than that reported for a parallel plate electrochemical reactor under laminar flow conditions. The mass-transfer enhancement factor related to an annular duct with axial developing flow ranges from 8 to 11. This high value is the consequence of two factors: (i) the intensive forced convection produced by the swirling flow at the outer electrode and (ii) the sudden expansion of the flow at the entrance due to the small tangential inlet. The fed of a gas phase in the reactor has scarce influence on the mass-transfer performance. A comparison of mass-transfer results with previous studies is made.

Treatment of hospital indoor air by a hybrid system of combined plasma with photocatalysis: Case of trichloromethane

The purpose of this study is to evaluate the efficiency of non-thermal plasma and heterogeneous photocatalysis processes for indoor air treatment using cylindrical continuous reactor at pilot scale and high flow rates. Trichloromethane (CHCl3) also called chloroform was chosen as a model pollutant representing hospital indoor air. This pollutant is considered as carcinogenic, mutagenic and reprotoxic agent. The effect of several parameters such as inlet pollutant concentrations (25–300 mg m−3), flow rates (2–8 m3 h−1), relative humidity of the effluent (5, 30, 50 and 90%) as well as input of the plasma discharge (9–21 kV) on the photodegradation of trichloromethane is investigated.Our findings show that the increase of flow rate leads to a reduction of degradation efficiency, while the humidity promotes the degradation in the case of photocatalysis process due to the formation of OH radicals.Moreover, the addition of a photocatalyst under UV radiation in the discharge zone enhances the reduction of ozone and CO gases compared to plasma process alone.The combination of plasma DBD and photocatalysis enhances the removal efficiency with a synergetic effect, leading to removal efficiency higher than 10% if we consider the sum of the contribution of each process separately.

Conversion of CO2 in a packed-bed dielectric barrier discharge reactor

The conversion of CO2 into CO and O2 in a quartz cylindrical packed-bed dielectric reactor has been studied using CO2 and Ar gas mixtures at atmospheric pressure and near ambient temperature with quartz wool, γ-Al2O3, and TiO2 packing. The highest energy efficiencies and conversion rates were observed with TiO2 packing in 20% CO2 in Ar: 30% conversion with 2.9% energy efficiency, and 17.5% conversion with 5.0% energy efficiency. Both γ-Al2O3 and quartz wool also showed an enhancement in conversion over an unpacked reactor. The percentage of CO2 to Ar in the range of 20%–60% is shown to have only a minor effect on reactor performance. Conversion as a function of power input and flow rate is studied in detail for γ-Al2O3 and TiO2 packing with similar particle sizes. In both cases, simple chemical kinetic models show that the CO production rate is nearly equal for both materials, while reverse reaction rates to CO2 are doubled for γ-Al2O3 compared to TiO2. From detailed charge–voltage (Q-V) analysis of all four reactor configurations, it is revealed that the electric field at which discharging occurs is higher for both γ-Al2O3 and TiO2 as compared to the empty or quartz wool filled reactors. Comparing kinetic model results with the electrical Q-V analysis, it appears likely that the higher and similar magnitude electric fields occurring with γ-Al2O3 and TiO2 are directly responsible for the increased CO production rates via increased electron energies in the discharge. The higher reverse reaction rates for γ-Al2O3, and its subsequent poorer performance compared to TiO2, can be attributed to a significantly higher effective surface area, which increases undesirable surface reactions between CO and oxygen species.

Facile Synthesis and High Activity of Novel Composite C/Fe-BiVO₄ Photocatalyst for Degradation of Cipfloxacin.

A novel C/Fe-BiVO4 nanosheet composite photocatalyst combining the properties of both semiconductor and Fenton like catalyst was prepared via a two-step method involving Resin carbonization and hydrothermal process. The samples were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS), X-ray photoelectron spectroscopy (XPS), Fourier transformed infrared spectroscopy (FT-IR) and nitrogen adsorption-desorption measurements and fluorescence spectrum technique. Structure analyses indicated that C/Fe-BiVO4 presented a nanosheet and macro-meso dual porosity structure. Photocatalytic degradation of cipfloxacin (CIP) (10 mg/L) was studied using C/Fe-BiVO4 under simulated solar light (SSL) irradiation in a cylindrical reactor. Three experimental parameters were chosen as independent variables: pH, C/Fe-BiVO4 concentration, and H2O2 concentration. The catalyst shows high catalytic activity in cipfloxacin photodegradation reaction with the cipfloxacin conversion efficiency higher than 95.61% at experimental conditions (catalyst dose, 0.75 g · L-1; H2O2 dose, 200 mg · L-1; solution pH, 5.0). The process obeyed the pseudo first-order kinetics by assuming a constant concentration of OH•. The as-prepared composite exhibited high efficiency in the photocatalytic decomposition of Cipfloxacin (CIP) by the assistance of H2O2. This method is promising due to its inexpensive starting materials and good photocatalyst for degradation of emerging micropollutants.

Characteristics of photocatalytic decomposition of individual and binary mixture vapors of some VOCs by a cylindrical UV reactor with helically installed TiO2-coated perforated planes

The photocatalytic decomposition characteristics of individual and binary vapors of benzene, toluene, and ethylbenzene by a UV reactor were studied. The reactor was custom-designed to have a synergistic effect of photochemical oxidation by ozone generated by UV254+185 nm lamps and photocatalytic oxidation by TiO2 photocatalyst whose surface area was almost doubled by helically inserted TiO2-coated perforated planes. The removal efficiencies of individual vapors of benzene, toluene, and ethylbenzene generally increased in proportion to the relative humidity and oxygen supply. The photocatalytic decomposition kinetics of individual vapors, as well as binary vapors consisting of benzene-toluene, benzene-ethylbenzene, and toluene-ethylbenzene, followed the Langmuir-Hinshelwood (L-H) equation quite well. Maximum elimination capacities of individual vapors were 560 g/m3∙day, 630 g/m3∙day, and 1,024 g/m3∙day for benzene, toluene, and ethylbenzene, respectively. In view of mutual impact for the photocatalytic decomposition of binary vapors, the reaction rate of the target component was more influenced by the presence of the counter component with lower bond dissociation energy.

Experimental evaluation of two low temperature energy storage prototypes based on innovative cementitious material

The world’s energy consumption has huge environmental and socioeconomic impacts. Heat storage allows the use of renewable energy in buildings to be increased and enhances their energy storage performance. Ettringite material has the advantage of high energy storage density at low temperature (60 °C) compared to existing adsorbent materials such as zeolites (around 200 °C). The objective of this study was to build and improve an experimental prototype of a thermochemical reactor to serve as a proof of concept. A previously modelled cylindrical thermochemical reactor with an axial metal tube was built in the laboratory. It was the first prototype, with a heat storage yield of 44% or storage capacity of 61 kWh/m3. To improve the heat storage performance of the thermochemical reactor, a second prototype without the metal tube was also developed in the laboratory. The storage tests with this second prototype showed a heat storage yield increase from 44% to 71%, with a storage density of 117 kWh/m3.

Optimization of advanced oxidation process based on persulfate (Uv/Na2s2o8/Fe2+) for phthalic acid removal from aqueous solutions with response surface methodology

BACKGROUND AND OBJECTIVE: Phthalic acid has high toxicity and low degradability which has put treatment of wastewater containing this compound prior to prevent its health and environmental hazards. Present study was conducted to Optimization of (UV/Na2S2O8/Fe2+) process for phthalic acid removal from aqueous solutions with response surface methodology. METHODS: This is an experimental study which was conducted at laboratory scale and synthetically in the cylindrical reactor containing UV-C lamp with 16 Watt power. Effects of variables including pH of solution (3-11), reaction time (0-60 min), concentration of persulfate (0.1-0.5 mmol/L), concentration of Fe2+ (0.1-0.2 mmol/L) and initial phthalaic acid (5-50 mg/L) on efficacy of process were investigated by response surface method (box Behnken method). The residual concentration of phthalic acid was measured by HPLC at a wavelength of 254 nm FINDINGS: The removal efficiency of phthalic acid increased by increasing pH level and reaction time. The maximum removal efficiency of phthalic acid attained as 98 percent at pH of 11, reaction time of 60 min, 0.15 mmol/L of Fe2+ concentration, persulfate concentration of 0.3 mmol/L and 5 mg of phthalic acid. The process of removing phthalic acid followed from first-order kinetic (R2=0.9766). The effects of all studied independent variables with p<0.05 on removal efficiency of phthalic acid were found significant. CONCLUSION: Obtained results indicated that the UV/Na2S2O8/Fe2+ process for removing phthalic acid from the aquatic environments has high efficiency. This issue confirms the acceptable efficiency of mentioned method for the removal of phthalic acid. © 2018, Babol University of Medical Sciences. All rights reserved.

Combustion properties of a low-vulnerability propellant: an experimental and theoretical study using laser ignition

ABSTRACTIgnition and combustion characteristics of a low-vulnerability propellant based on RDX are studied experimentally. Ignition is obtained using a laser diode. Experiments are performed in a cylindrical closed-volume reactor for different initial pressures and initial propellant masses under nitrogen and argon surrounding atmospheres. Ignition delays, maximal overpressures, and propagation rates are obtained for different initial pressures and laser powers. Thermodynamic predictions of overpressures are also compared with experimental ones. Finally, ignition probabilities for different laser powers and gaseous atmospheres are investigated using a revised Langlie method.

Numerical Study of Methane–Oxygen Premixed Flame Characteristics in Non-adiabatic Cylindrical Meso-Scale Reactors with the Backward-Facing Step

In the present study, the effects of reactor diameter, inlet velocity, velocity profile, equivalence ratio (Phi, Ф), and outer wall convective and radiative heat transfer coefficients on flame characteristics in cylindrical non-adiabatic meso-scale reactors with the backward-facing step were investigated numerically. The results showed that these parameters could strongly affect the mole fraction of radical species within the flame zone. Also, it was shown that as compared to the reactor with 3 mm inner diameter, increasing the inlet velocity in the reactor with 5 mm inner diameter may lead to the opposite effect on the flame location. In addition, it was observed that the velocity profile could sensibly affect the flame location, temperature, and the species mole fractions in the meso-scale reactors. Moreover, it was demonstrated that the effect of equivalence ratio on the flame characteristics was more crucial for the reactors with smaller diameters. Furthermore, it was maintained that the outer wall convective and radiative heat transfer coefficients could cause the flame instability in the meso-scale reactors because of decreasing the mole fraction of important species such as O, H, and OH in the vicinity of the reactor inner wall.

Macro- and micro-scale mixing in a shaken bioreactor for fluids of high viscosity

Orbitally shaken bioreactors, OSRs, are commonly employed in the pharmaceutical industry at the drug development and screening stage, because they provide a high throughput solution where several cell cultures can be run in parallel. In general cell-culture media used in bioprocessing exhibit a viscosity close to water, but this hypothesis is less valid when high density cell cultures are considered, such as in continuous fermentations, where cells are retained in the bioreactor at large densities and the drug-product is continuously removed and fed to the downstream capture steps of the process. In this context the viscosity of the culture media increases with culture time and with the amount of biomass present in the reactor. In this frame of work two sets of measurements, based on DIMST and pLIF, were carried out to further study the mixing dynamics in a orbitally shaken cylindrical reactor when fluids of viscosity higher than water are considered. These data allowed to identify different flow transitions, which have not been previously observed in the PIV experiments of Ducci and Weheliye (2014). The mixing time measurements highlighted the presence of a poor mixing region for all the flow regimes considered, irrespective of the vortical structure present in the flow, and an attempt was made to quantify the diffusion process occurring at the edges of this region. A more detailed understanding of the flow and deformation dynamics occurring at small scales can be gained from the pLIF measurements. These allowed to visualise the lamellar structures induced by the flow deformation occurring over several orbital cycles. The growth rate of the material lines was estimated and compared to models commonly employed in the literature to assess mixing dynamics. These information are relevant for micro-mixing models, when the mixing process is limited by the growth of the interfacial area rather than the reaction time.

Decolorization of Reactive Red 239 Via Heat Activated Persulfate

Effluents of cotton dyeing process of textile industry is considered as extremely polluted due to presence of unfixed azo dyes and auxiliary chemicals. The complex aromatic structure and non-biodegradability nature of azo dyes involved new and efficient treatment technologies to eliminate intense color from textile wastewater. In recent years, in-situ chemical oxidation technology (ISCO) using persulfate (S2O82-) as an oxidant has appeared to be a promising method for removal of azo dyes. S2O82- can be activated by UV, heat or transition metals to generate sulfate radical (SO4-). In this study, decolorization of Reactive Red 239 (RR239) azo dye via heat activated S2O82- was explored. Experiments were conducted in a cylindrical batch reactor equipped with a water jacket. Effect of parameters such as temperature, pH and S2O82- concentration on decolorization of RR239 was investigated. The results show that decolorization efficiency was enhanced with increasing temperature from 45 to 55°C but further increase in temperature did not enhance decolorization. The pseudo first order rate constant values fit well Arrhenius equation, yielding an activation energy of 108.75 kJ mol-1 for decolorization of RR239. The highest decolorization efficiency was obtained at pH=3 under the tested pH range. As S2O82- concentration increased decolorization efficiency increased. 89.67% and 39.05% decolorization and aromatic degradation efficiencies were observed within 120 minutes of reaction time, respectively. These results show that heat activated S2O82- method was a feasible method for decolorization of RR239.

Treatment of compost leachate by ferro-sonication process: Effect of some operational variables

Aim: Application of composting process for the management of organic solid waste led to the production of leachate, which causes many problems to environment. This study was aimed at investigation of ferro-sonication (FS) process in composting leachate degradation. Materials and Methods: Leachate samples were collected in composting factory located in Isfahan. In each run, 400 ml of leachate was sonicationed through an ultrasonic homogenizer in a cylindrical glass reactor. Ferrous sulfate was added to the reactor as accelerator agent. The effect of various parameters including pH, ferrous sulfate doses, sonication times, and ultrasonic intensity was studied in the removal of chemical oxygen demand (COD) and biological oxygen demand (BOD) from composting leachate. Results: The results showed that the COD and BOD removal rate was increased by increasing ferrous sulfate dosages, sonication time, and ultrasonic intensity. In addition, lower pH was favored for leachate degradation. In general, the optimum conditions for pH, ferrous sulfate dosage, irradiation time, and ultrasonic intensity were 3, 8 mmol, 180 min, and 150 W, respectively. Approximately 46% of COD and 33% of BOD were removed in optimum condition. Conclusion: These results revealed that FS can be effective in degradation of compost leachate and can be presented as a good choice for pretreatment of leachate.