Real Industrial Effluent Research Articles

Optimization of a single chamber microbial fuel cell using Lactobacillus pentosus: Influence of design and operating parameters

Microbial fuel cells (MFCs) have been receiving an increased attention over the last years due to their potential to combat two global problems: waste pollution and energy demand. Additionally, when a wastewater is used, MFCs can perform its treatment while recovering energy, leading to the possibility of energy-producing wastewater treatment plants, offsetting their operational costs. However, to overcome their current limitations (lower power outputs and higher costs), a clear understanding of the effect of operation and design parameters on its overall performance is mandatory. Therefore, the goal of this work was to evaluate the effect of operating conditions - batch cycle and yeast extract concentration, and design parameters - anode electrode area, membrane thickness and active area, on the overall performance of a single chamber MFC. The MFC operated with a pure culture of Lactobacillus pentosus and a synthetic wastewater based on a real dairy industry effluent. The overall performance was evaluated through the power output and the COD removal rate. Additionally, the biofilm formed at the anode electrode was characterized in terms of biomass, proteins and polysaccharides content. For the conditions used in this work, a maximum power density of 5.04 ± 0.39 mW/m2 was achieved with an anode electrode area of 61 cm2, a batch cycle of 48 h, 50 mg/L of yeast extract and a Nafion 212 membrane with an active area of 25 cm2. The different conditions tested had a clear effect on the MFC energy production and biofilm characteristics, but not on the ability of L. pentosus to treat the dairy wastewater. The COD removal rates were in the range between 42% and 58%, for all the conditions tested.

The band structure control of visible-light-driven rGO/ZnS-MoS2 for excellent photocatalytic degradation performance and long-term stability

ZnS-MoS2 solid solution anchored on reduced graphene oxide sheet (rGO/ZnS-MoS2) was explored as novel visible-light-driven photocatalysts, and synthesized by solvent thermal method. The light absorption intensity of rGO/ZnS-MoS2 was greatly strengthened, and rGO/ZnS-MoS2 possess modulated continuous band gaps from 3.47 to 3.56 eV by changing the Zn/Mo ratios and rGO content. Their photocatalytic activities for 2-nitrophenol degradation are dependent on the chemical composition, and the optimal 11% rGO/ZnS-MoS2 possessed the highest photocatalytic performance, which could be attributed to the most efficient charge separation, the largest specific area, and its optimized band structure. Moreover, 11% rGO/ZnS-MoS2 can effectively treat real industrial effluent with 74.05% COD removal, and maintain long-term stability without obvious decline after five use cycle.

Implementation of fluidized-bed Fenton as pre-treatment to reduce chemical oxygen demand of wastewater from screw manufacture: Influence of reagents feeding mode

Abstract Advanced oxidation processes (AOPs) are promising technologies to mineralize organic pollutants and reduce chemical oxygen demand (COD) from water effluents. Unfortunately, treatment of real industrial effluents is barely reported in literature and actual application is rare. One of the technology transfer limitations is associated to the identification of the most suitable stage for AOPs implementation in existing water treatment facilities of industry manufacturers. Here, we report a complete study where the most suitable stage for Fenton treatment implementation for a screw manufacture industry water treatment facility is identified. Actual wastewater effluent was collected, characterized and treated by means of Fluidized-bed Fenton (FBF) treatment to reduce COD levels. Fenton’s reagents feeding mode is evaluated to better understand influence on continuous flow operational FBF performance and efficiency.

Catalytic metal oxide nanopowder composite Ti mesh for electrochemical oxidation of 1,4-dioxane and dyes

Electrocatalytic degradation of micropollutants is an attractive strategy for advanced wastewater management, but the development and optimization of innovative anodic materials are needed. This study investigated newly designed metal-TiO2 nanopowder composite coated Ti mesh anodes for enhanced degradation of 1,4-dioxane (10 mg/L spiked) and dyes present in real industrial wastewater effluents. Based on multi-component mixture coating tests, a metal-TiO2 composite for the most efficient electrocatalytic degradation of 1,4-dioxane was attained in the binary molar composition range of Ru:Ti = 0.6:0.4–0.9:0.1. Interestingly, Ir addition (i.e., ternary metal oxide composite) always had an antagonistic impact on the electrocatalytic performance. The binary metal oxide composite structure was X-rayed and identified as comprising RuO2-TiO2 crystals. Substantive removal of 1,4-dioxane and color was achieved with a small coating amount, but thicker coating had no or negative effects. This is possibly because the production of the oxidants responsible for organics degradation (reactive chlorine species and hydrogen peroxide) decreases with excessive coating layers. A properly coated binary RuO2-TiO2 composite Ti mesh anode was as effective (or more so) than the boron-doped diamond electrode in terms of 1,4-dioxane degradation and decolorization of real textile wastewater.

Regression model, artificial neural network, and cost estimation for biosorption of Ni(II)-ions from aqueous solutions by Potamogeton pectinatus

ABSTRACTThis study investigated the application of Potamogeton pectinatus for Ni(II)-ions biosorption from aqueous solutions. FTIR spectra showed that the functional groups of –OH, C–H, –C = O, and –COO– could form an organometallic complex with Ni(II)-ions on the biomaterial surface. SEM/EDX analysis indicated that the voids on the biosorbent surface were blocked due to Ni(II)-ions uptake via an ion exchange mechanism. For Ni(II)-ions of 50 mg/L, the adsorption efficiency recorded 63.4% at pH: 5, biosorbent dosage: 10 g/L, and particle-diameter: 0.125–0.25 mm within 180 minutes. A quadratic model depicted that the plot of removal efficiency against pH or contact time caused quadratic-linear concave up curves, whereas the curve of initial Ni(II)-ions was quadratic-linear convex down. Artificial neural network with a structure of 5 – 6 – 1 was able to predict the adsorption efficiency (R2: 0.967). The relative importance of inputs was: initial Ni(II)-ions > pH > contact time > biosorbent dosage > particle-size. Freundlich isotherm described well the adsorption mechanism (R2: 0.974), which indicated a multilayer adsorption onto energetically heterogeneous surfaces. The net cost of using P. pectinatus for the removal of Ni(II)-ions (4.25 ± 1.26 mg/L) from real industrial effluents within 30 minutes was 3.4 $USD/m3.

Polydopamine coating assisted synthesis of MnO2 loaded inorganic/organic composite electrospun fiber adsorbent for efficient removal of Pb2+ from water

Polydopamine (PDA) and MnO2 have been proven to be promising adsorbents to capture Pb2+ from wastewater. In this study, MnO2 was in-situ loaded onto flexible electrospun polyacrylonitrile (PAN) fibers by the assistance of polydopamine coating (MnO2/PDA/PAN fibers) and the as-obtained MnO2/PDA/PAN fibers were utilized for the removal of Pb2+ from water. The structure and chemical composition of MnO2/PDA/PAN fibers were characterized in detail. The results indicated that the PDA coating onto PAN fibers can’t be neglected for loading MnO2. This preparation of MnO2/PDA/PAN fibers could avoid the agglomeration of MnO2 particles and make the adsorbent separate easily from the adsorption solution. The adsorption experiments showed that the adsorption process toward Pb2+ by MnO2/PDA/PAN fibers followed pseudo-second-order model and Langmuir isotherm model. In comparison with PDA/PAN fibers and MnO2/PAN fibers, MnO2/PDA/PAN fibers showed higher Pb2+ adsorption capacity. The maximum adsorption capacity calculated from Langmuir model was 185.19 mg/g, which is higher than most of the reported PDA or MnO2 based Pb2+ adsorbents. The adsorption toward Pb2+ by MnO2/PDA/PAN fibers still maintained stability after five adsorption/desorption cycles. In addition, the fiber adsorbent could also adsorb Pb2+ from real industrial effluent with removal efficiency above 95%. This work indicates that MnO2/PDA/PAN fibers have great potential to be used as effective adsorbents for practical Pb2+ removal.

Competitive biosorption of heavy metals from aqueous solutions onto Streptomyces rimosus

The aim of this study is the simultaneous biosorption of Cd+2 and Ni+2 on a dead biomass, Streptomyces rimosus pretreated with NaOH (0,1 M). Kinetic tests were carried out for the binary mixture (cadmium-nickel) during 6 hours contact time to ensure that balance was reached. The amounts adsorbed at equilibrium were 22.8 mg Ni2+/g and 9.86 mg Cd2+/g biomass, respectively. The biosorption depends mainly by some parameters, such as the pH, the initial concentration of metal and the initial concentration of biomass. The isotherm of adsorption according to two models, Langmuir and Freundlich, was carried out in our study. The results of the kinetics of adsorption show that the experimental values are well represented by the kinetic model of pseudo-second order. This enables us to determine the behavior of these adsorbents with respect to a real industrial effluent.

One-pot synthesis of Mn3O4/graphitic carbon nanoparticles for simultaneous nanomolar detection of Pb(II), Cd(II) and Hg(II)

In this paper, a facile one-step sucrose–nitrate decomposition method has been proposed to synthesis Mn3O4 nanoparticles (Mns)/graphitic carbon. The prepared material has been characterized by X-ray diffraction, Fourier transform infrared spectrometer, surface area analysis and transmission electron microscopy. The prepared Mns/graphitic carbon is drop-casted on glassy carbon electrode to allow the fabrication of electrochemical sensors for the simultaneous detection of Pb(II), Cd(II) and Hg(II) at nanomolar (nM) levels in aqueous solutions via differential pulse anodic stripping voltammetry. The proposed Mns/graphitic carbon sensors exhibit a wide linear range from 20 to 680 nM towards the simultaneous sensing of Cd(II), Pb(II) and Hg(II), and the corresponding limits of detection were found to be 0.48 × 10−11, 9.66 × 10−11 and 0.51 × 10−11 M, respectively. The practical application of the proposed sensor is evaluated within a real battery, industrial and chrome plating effluents.

Fixed-bed column studies of total organic carbon removal from industrial wastewater by use of diatomite decorated with polyethylenimine-functionalized pyroxene nanoparticles

In this study, a fixed-bed column adsorption process was employed to remove organic pollutants from a real industrial wastewater effluent using polyethylenimine-functionalized pyroxene nanoparticles (PEI-PY) embedded into Diatomite at very low mass percentage. Various dynamic parameters (e.g., inlet concentration, inlet flow rate, bed height, and PEI-nanoparticle concentration in Diatomite, (%nps)) were investigated to determine the breakthrough behavior. The obtained breakthrough curves were fit with a convection-dispersion model to determine the characteristic parameters based on mass transfer phenomena. The axial dispersion coefficient (DL) and group of dimensionless numbers; including Renold number (Re), Schmidt number (Sc), and Sherwood number (Sh) were all determined and correlated by Wilson-Geankoplis correlation that was used to estimate the external film diffusion coefficients (Kc) at 0.0015 < Re<55.

Photocatalytic treatment of dye wastewater and parametric study using a novel Z-scheme Ag2CO3/SiC photocatalyst under natural sunlight

Ag2CO3 is a known photocatalyst active in the visible region of solar spectrum. In the present study, a series of novel hybrid Ag2CO3/SiC nanostructures have been successfully synthesised through a simple precipitation route. The photocatalytic performance was evaluated by the degradation of MB under natural solar irradiation. It was observed that heterojunction with SiC improves its photoactivity by inducing a charge transfer between SiC and Ag2CO3 mimicking the Z-scheme in photosynthesis, proved by scavenger studies. The photocatalysts were characterized by XRD, SEM with EDX, TEM, TGA-DTG and UV-Vis/NIR. The best photocatalytic results and formal quantum efficiency (FQE) under natural sunlight were obtained with SCSC-12 nano-composite. The percentage photo-discolouration of MB over SCSC-12 was 98% against 90% with conventional TiO2. Factors viz., photocatalyst dosage, solution pH, solar intensity, substrate and its initial concentration and speed of agitation were found to influence photo-treatment. Corresponding optimum parametric values have been found and reported in terms of FQE. As a case study, performance of the photocatalyst was investigated on a real industrial effluent and rate expression developed in terms of TOC and [TOC]0. The present work, which includes a parametric study, has been carried out in direct solar light and is expected to be useful in real-time solar photocatalytic design of reactors and other solar applications for environmental remediation.

Application of Electrochemical Technology for Water Treatment of Brazilian Industry Effluents

Electrochemical technologies are a promising alternative for the treatment of wastewaters containing organic pollutants. The main advantages of these processes include environmental compatibility, versatility, energy efficiency, safety, selectivity, amenability to automation and cost effectiveness. However, the effectiveness of the electrochemical approaches depends strongly on electrode materials and cell parameters (mass transport, current density, water composition, etc.). Then, the use of high performance anodic materials can achieve high efficiency and lower the operating cost. Therefore, several research groups are recently studying the applicability of the electrochemical technologies for treating real domestic and industrial effluents, with the aim of that a diversification of techniques must be sought, adapting the treatment to each situation, as much as possible. In this context, this paper presents an overview of the application of electrochemical technologies to treat industrial effluents in the northeastern region of Brazil, emphasizing the use of direct and indirect electrochemical oxidation processes as an alternative to pollution abatement of effluents generated by textile and petrochemical industries.

A more eco-friendly synthesis of flocculants to treat wastewaters using health-friendly solvents

The main objective of this work was to investigate the possibility of producing new polyelectrolytes (flocculants) synthesized using health-friendly ingredients. A well-known copolymer used in water treatment, poly(acrylamide-co-2-(acryloyloxy)ethyltrimethyl ammonium chloride), was prepared by inverse-emulsion polymerization using new alternative organic phases. Specifically, three different purified oils of liquid saturated hydrocarbons with high boiling point and high purity were tested as synthesis media in the development of copolymers with different charge densities. In all of these oils, the toxic polycyclic aromatics and the heavy metals were not present. The polyelectrolytes were characterized in terms of shear viscosity, hydrodynamic diameter, molecular weight, zeta potential, intrinsic viscosity, and chemical composition (13C NMR and FTIR). Final results revealed the success of the application of the new health-friendly formulation in the polymerization to produce polyelectrolytes and, additionally, the polymers produced had good flocculation efficiency in two different real industrial effluents.

Electrical energy per order determination for the removal pollutant from industrial wastewater using UV/Fe2+/H2O2 process: Optimization by response surface methodology

Comparison of UV, H2O2, Fe2+, UV/H2O2, UV/Fe2+, Fe2+/H2O2 and UV/Fe2+/H2O2 processes for the removal of percentage color, COD and electrical energy per order from the effluent distillery industry. The results showed that, UV/Fe2+/H2O2 process yield higher percentage color and COD removal with low electrical energy per order than UV, UV/H2O2, UV/Fe2+ process. To obtain the UV/Fe2+/H2O2 process performance by operating various parameters on the percentage color and COD removal using response surface methodology. A Regression quadratic model describing the percentage color and COD removal efficiency of UV/Fe2+/H2O2 process were developed and validate by analysis of variance. Experimental results showed that, UV/Fe2+/H2O2 process can effectively reduced 96.50% of color and 84.40% of COD removal of the distillery industry wastewater under the optimum conditions such as Fe2+–1.50mM, H2O2–200mM, COD–1500ppm and pH–3.2, respectively. Result concluded that, UV/Fe2+/H2O2 process can be used effectively for the treatment of real industrial effluent.

Treatment of wastewater by mixed bacterial consortium in continuous reactors packed with solid waste

Phenol is one of the priority pollutants as declared by EPA (USA). Very few comparative studies have been carried out with continuous packed bed reactors (PBR) for bacterial degradation of phenol and applying the result in real time situation. The present study compared the performance of a co-current and a counter-current continuous PBR in degrading phenol by a mixed consortium of bacteria isolated from the East Calcutta Wetlands based on both rate of phenol degradation and phenol removal efficiency. Different process parameters like air flow rate, hydraulic retention time and temperature were varied for both the systems. Performance of the co-current continuous PBR was found to be more efficient. To validate the performance of this system in actual application in industry a real time phenolic industrial effluent was fed to this system. Phenol degradation rate was 1.43mg/lmin and the phenol removal efficiency of this co-current continuous PBR was 72.85%.

Chromium (VI) Removal from Wastewater by Electrocoagulation Process Using Taguchi Method: Batch Experiments

Electrocoagulation is an electrochemical method for treatment of different types of wastewater whereby sacrificial anodes corrode to release active coagulant (usually aluminium or iron cations) into solution, while simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation or settling. The Taguchi method was applied as an experimental design and to determine the best conditions for chromium (VI) removal from wastewater. Various parameters in a batch stirred tank by iron metal electrodes: pH, initial chromium concentration, current density, distance between electrodes and KCl concentration were investigated, and the results have been analyzed using signal-to-noise (S/N) ratio. It was found that the removal efficiency of chromium increased with increasing current density and KCl concentration, and decreases with increasing initial chromium concentration and distance between electrodes, while pH shows peak performance curve. Experimental work have been performed for synthetic solutions and real industrial effluent. The results showed that the removal efficiency of synthetic solution is higher than industrial wastewater, the maximum removal for prepared solution is 91.72 %, while it was 73.54 % for industrial wastewater for the same conditions.

Ultrasound assisted mixed azo dye adsorption by chitosan–graphene oxide nanocomposite

Mixed azo dyes present in various effluents may often impair adsorption efficiency thereby questioning applicability of the same in a real-time scenario. In this study, simultaneous adsorption of acid yellow 36 (AY) and acid blue 74 (AB) from their aqueous solutions was carried out with graphene oxide nanoplatelets embedded in chitosan matrix (GO–Cs–Nc) with assistance of ultrasound exposure. Results obtained were subjected to analysis for process isotherms, kinetics and thermodynamics. This process was also optimized for best results using response surface methodology (RSM) and modelled with artificial neural network (ANN). The nanocomposite was characterised both before and after adsorption using FTIR, SEM, TEM and AFM. Under the experimental conditions prescribed by RSM, 0.50gL−1 of adsorbent was responsible for 98.18% and 98.80% removal of AY and AB respectively when exposed to 6.48min of ultrasonic irradiation. Hence, ultrasound assisted GO–Cs–Nc proved to be a cost effective and sustainable adsorbent effective in low dosage and significantly reduced time with possible application for treatment of real industrial effluents rich in mixed dyes.

Mercury Detection in Real Industrial Flue Gas Using a Nanostructured Quartz Crystal Microbalance

We present for the first time a nanostructured gold-based microsensor that can successfully detect elemental mercury (Hg0) vapor through a nonspectroscopic means, directly from a real industry effluent gas sample obtained from an alumina refinery. The developed sensor did not require any preconditioning of the sampled industrial gas in order to remove humidity content as is the case for laborious solid sorbent methods (i.e., Appendix K and Method 30B) certified by the United States Environmental Protection Agency (US-EPA). The sensor was developed by electrodepositing gold (Au) nanostructures (nanospikes) directly on the electrodes of the humble quartz crystal microbalance (QCM) transducer. Significantly, despite attempting to introduce a memory effect into the sensor in order to replicate real world scenarios during testing, the developed sensor still reported the Hg0 vapor concentrations in the industrial gas to within ±8% of the certified solid sorbent analysis conducted at the time of obtaining the sa...

Two fold modified chitosan for enhanced adsorption of hexavalent chromium from simulated wastewater and industrial effluents

Ionic solid (Ethylhexadecyldimethylammoniumbromide) impregnated phosphated chitosan (ISPC) was synthesized and applied for enhanced adsorption of hexavalent chromium from industrial effluent. The compound obtained was extensively characterized using instrumental techniques like FT-IR, TGA-DTA, XRD, SEM, BET and EDX. ISPC showed high adsorption capacity of 266.67mg/g in accordance with Langmuir isotherm model at pH 3.0 due to the presence of multiple sites which contribute for ion pair and electrostatic interactions with Cr(VI) species. The sorption kinetics and thermodynamic studies revealed that adsorption of Cr(VI) followed pseudo-second-order kinetics with exothermic and spontaneous behaviour. Applicability of ISPC for higher sample volumes was discerned through column studies. The real chrome plating industry effluent was effectively treated with total chromium recovery of 94%. The used ISPC was regenerated simply by dilute ammonium hydroxide treatment and tested for ten adsorption-desorption cycles with marginal decrease in adsorption efficiency.

Treatment of high-strength wastewater by Fe2+-activated persulphate and hydrogen peroxide

Ferrous ion-activated persulphate and hydrogen peroxide were studied for the treatment of real high-strength industrial effluent. The Fenton process demonstrated greater organic load removal, biodegradability improvement and toxicity reduction as well as lower treatment cost than the activated persulphate system. However, the use of an activated persulphate process was more favourable due to the exothermic effect intrinsic to the Fenton reaction, which resulted in a rapid increase in the temperature of the high-strength wastewater along with excessive foam formation. Overall, for the H2O2/Fe2+ and processes, the application of a chemical oxygen demand (COD)/oxidant/Fe2+ weight ratio of 1/0.4/0.075 resulted in a COD removal of 58 and 50%, a 7-day biochemical oxygen demand/COD ratio increase from 0.14 to 0.3 and 0.23, and an increase in the EC50 (Daphnia magna) by 6.5-fold and 2.9-fold, respectively. The stepwise addition of the oxidant and activator was favourable for the Fenton process and resulted in negligible improvement in the wastewater treatment efficacy in the activated persulphate system.

Feasibility of electrocoagulation/flotation treatment of waste offset printing developer based on the response surface analysis

In the printing plate developing process, the offset printing developer undergoes changes, as well as enrichment by the various chemicals, i.e. metals, organic binders and photosensitive compounds. The objective of this study was to investigate the electrocoagulation/flotation (ECF) treatment efficiency for the removal of copper, turbidity and organic substances from the waste offset printing developer (WOPD). The effect of operational parameters, such as electrode materials, current density, interelectrode distance and operating time, was studied. Also, the response surface analysis was applied to evaluate the effect of main operational variables and to get a balanced removal efficiency of investigated WOPD parameters by ECF treatment. The removal efficiency increases significantly with the increasing of operating time and mainly increases with the increasing of current density. The obtained results show that the interelectrode distance and combinations of electrodes determine the removal efficiency of copper, turbidity and organic substances. Based on the obtained results, the optimized parameters for the ECF treatment removal of investigated WOPD parameters were identified as: Al(−)/Fe(+) electrode combination with interelectrode distance of 1.0cm, operating time of 5min and current density of 8mAcm−2. This study confirms the practical feasibility of ECF method for treating real printing industrial effluent under optimum conditions.