Pollutant Removal Processes Research Articles

Residence times of airborne pollutants in the urban environment

This study investigates the applicability and relevance of the residence time to the characterisation of airborne pollutant removal in the urban environment. Using large-eddy simulations of flow over an idealised building array and a realistic urban area, the statistical and spatial distributions of residence times are analysed for different source locations and wind conditions. For the idealised building array, the mean residence times in the avenue and intersection units depend on the mean flow, turbulent kinetic energy and wind direction. The probability density function (PDF) shows distinct early and late regimes when there are pollutant removal processes associated with different boundaries. For the realistic urban domain, the residence times are significantly shorter and stronger fluctuations are observed in the PDF, especially when the inflow winds are driven by the output from a high-resolution mesoscale model. The residence time is especially useful for applications to assessment and planning, when information about the timescale of pollutant removal is required and the flow is inhomogeneous and unsteady.

Degradation characteristics of four major pollutants in chemical pharmaceutical wastewater by Fenton process

Present study deals with the treatment of simulated chemical pharmaceutical wastewater (SCPW) using Fenton oxidation process for the degradation of typical pollutants containing n-butanol, ethyl p-nitrobenzoate, 4, 7-dichloroquinoline and ethyl acetoacetate. The effects of operational parameters like the initial pH, H2O2/Fe2+ molar ratio, H2O2 dosage and reaction time on the degradation efficiency of pollutants and biodegradability of SCPW were investigated. The Fenton reaction steps and the removal kinetics of SCPW were analyzed. Finally, the effects of the molecular structure on the degradation efficiency of organics were investigated. The degradation ratio of n-butanol, ethyl acetoacetate, 4, 7-dichloroquinoline, ethyl p-nitrobenzoate and chemical oxygen demand (COD) in SCPW is 56%, 75%, 100%, 78% and 38%, respectively, for conditions of initial pH of 2.5, H2O2/Fe2+ molar ratio of 20, H2O2 dosage of 0.6 Q (Q is the theoretical dosage of Fenton reagent) and reaction time of 30 min. The reaction steps analysis indicated that the biodegradability of SCPW was improved mainly by the oxidation intermediate of pollutants. The kinetics study showed that the removal processes of pollutants and COD were consistent with the second-order kinetic model. Quantum chemical analysis showed that the correlation between the total energy ERB3LYP and removal kinetic constant K[RH] was most significant, and ERB3LYP was negatively correlated with K[RH]. The results indicated that the higher the total energy of the organics, the more difficult it was to be removed. The findings reported herein are significant to predict the treatment efficiency of pollutants in real pharmaceutical wastewater.

Bioaugmentation and advanced oxidation process for organic and inorganic pollutants removal and pathogenic bacteria inactivation,s for El-Rahawy Drain, Egypt

River Nile (Rossita Branch) receives massive quantities of untreated or inadquite municipal wastewater, industrial and agricultural wastewater through El-Rahawy drain. Consequently, the objective of the present study was to design a system depending on biological treatment followed by Fenton reaction for treatment of El-Rahawy drain wastewater. The physicochemical and bacteriological parameters were estimated for El Rahawy drain wastewater and treated effluent of the drainage wastewater. The samples were collected after 24h and after the fourth day of the treatment. The bioaugmented bacterial consortium that used to enhance the biological treatment was nonpathogenic and eco-friendly, and the inoculated dose was 10 gm/m3/day. The removal efficiency of TDS reached 58.9% and 68.6 % by biological treatment after 24 h and 4 days. While the removal % of TDS reached 75.9% after 24 h of Fenton treatment, and this efficiency removal declined to 66.6% on the fourth day of the treatment. The removal efficiency of COD reached 33.3 and 56.8% after 24 h and 4 days of the biological treatment. Whereas the removal % of COD reached to 80% after 24 h, and this removal % declined to 78.8% after 4 days of Fenton treatment. The physicochemical and bacteriological parameters were declined by the treatment time increase. It was found that, the bioaugmented bacterial strains are able to grow well and produce more biodegeding enzymes after 24 h. Moreover, the biological treatment followed by the Fenton reaction is the most suitable solution for El-Rahawy drain treatment

Implementation of Floating Treatment Wetlands for Textile Wastewater Management: A Review

The textile industry is one of the most chemically intensive industries, and its wastewater is comprised of harmful dyes, pigments, dissolved/suspended solids, and heavy metals. The treatment of textile wastewater has become a necessary task before discharge into the environment. The textile effluent can be treated by conventional methods, however, the limitations of these techniques are high cost, incomplete removal, and production of concentrated sludge. This review illustrates recent knowledge about the application of floating treatment wetlands (FTWs) for remediation of textile wastewater. The FTWs system is a potential alternative technology for textile wastewater treatment. FTWs efficiently removed the dyes, pigments, organic matter, nutrients, heavy metals, and other pollutants from the textile effluent. Plants and bacteria are essential components of FTWs, which contribute to the pollutant removal process through their physical effects and metabolic process. Plants species with extensive roots structure and large biomass are recommended for vegetation on floating mats. The pollutant removal efficiency can be enhanced by the right selection of plants, managing plant coverage, improving aeration, and inoculation by specific bacterial strains. The proper installation and maintenance practices can further enhance the efficiency, sustainability, and aesthetic value of the FTWs. Further research is suggested to develop guidelines for the selection of right plants and bacterial strains for the efficient remediation of textile effluent by FTWs at large scales.

Role of Microorganisms in the Remediation of Wastewater in Floating Treatment Wetlands: A Review

This article provides useful information for understanding the specific role of microbes in the pollutant removal process in floating treatment wetlands (FTWs). The current literature is collected and organized to provide an insight into the specific role of microbes toward plants and pollutants. Several aspects are discussed, such as important components of FTWs, common bacterial species, rhizospheric and endophytes bacteria, and their specific role in the pollutant removal process. The roots of plants release oxygen and exudates, which act as a substrate for microbial growth. The bacteria attach themselves to the roots and form biofilms to get nutrients from the plants. Along the plants, the microbial community also influences the performance of FTWs. The bacterial community contributes to the removal of nitrogen, phosphorus, toxic metals, hydrocarbon, and organic compounds. Plant–microbe interaction breaks down complex compounds into simple nutrients, mobilizes metal ions, and increases the uptake of pollutants by plants. The inoculation of the roots of plants with acclimatized microbes may improve the phytoremediation potential of FTWs. The bacteria also encourage plant growth and the bioavailability of toxic pollutants and can alleviate metal toxicity.

Fast Start-Up ANAMMOX Operation Strategy and Flora Characteristics of a Biofilter

To achieve the rapid start-up of anaerobic ammonia oxidation (ANAMMOX) reaction at room temperature and sludge granulation, a small amount of ANAMMOX sludge was inoculated by an upflow biological filter reactor, and ANAMMOX was started by stage variable load and shortening hydraulic residence time (HRT) operation strategy. The reaction was evaluated, and the nitrogen removal characteristics of the biofilter were evaluated. The results showed that the biofilter started the ANAMMOX reaction in a medium-temperature (25-29℃) environment for 22 days. After 97 days of culture, the total nitrogen volume removal rate (NRR) reached 5.64 kg·(m3·d)-1, the total nitrogen (TN) removal rate was close to 80%, and the average particle size of the granular sludge was 4.5 mm. High-throughput sequencing analysis showed that the biofilter formed a layered structure of nitrifying bacteria-heterotrophic bacteria, anaerobic ammonium oxidation bacteria (AAOB), and AAOB-heterotrophic bacteria from bottom to top. The various microflora synergistically denitrified, creating a low dissolved oxygen (DO) stable environment for AAOB, and the dominant population Candidatus Kuenenia (AF375995.1) was enriched. In addition, the removal process of pollutants along the path and the characteristics of sludge along the process were analyzed, and it was verified that the sludge in the reaction zone had good ANAMMOX activity. An ANAMMOX-biofilter reactor achieves rapid start-up of the ANAMMOX reaction, sludge granulation, and efficient operation by effectively maintaining the amount of bacteria and stabilizing the reaction conditions.

Internal-micro-electrolysis-enhanced heterogeneous electro-Fenton process catalyzed by Fe/Fe3C@PC core–shell hybrid for sulfamethazine degradation

Core-shell structured hybrid octahedron, which contained a Fe-based nanoparticle core (Fe/Fe3C) and a graphitized porous carbon (PC) shell (Fe/Fe3C@PC), prepared through one-pot pyrolysis using MIL-101(Fe) as the sacrificial template, was used as a novel catalyst for the degradation of sulfamethazine (SMT) by heterogeneous electro-Fenton (Hetero-EF). Fe/Fe3C@PC outperformed common heterogeneous catalysts such as Fe0, Fe3O4 and Fe2O3 due to the synergistic effect between Fe/Fe3C nanoparticles and PC. The rate constant for SMT degradation in the Hetero-EF process was 7.17-folds of that in the heterogeneous Fenton (Hetero-F) process. The plausible catalytic mechanism and degradation pathway for mineralization of SMT by this Hetero-EF process were proposed, confirming the main role of surface-bound hydroxyl radical (OHads) oxidation. Moreover, internal-micro-electrolysis (IME)-enhanced Hetero-EF reaction was verified by experiments and density functional theory (DFT) calculations. Fe/Fe3C@PC could be easily recycled due to magnetism and well recovered via a simple thermal treatment in H2 atmosphere. This work enlightened metal–organic frameworks (MOFs) derived core–shell structured hybrids to be ultra-efficient heterogeneous catalysts and their catalytic mechanism promoting promising utilization in the Hetero-EF process for organic pollutants removal.

Influence of plasma treatment on the physical and chemical properties of sisal fibers and environmental application in adsorption of methylene blue

The sisal fiber (agave sisalana) is a natural material that presents interesting physical and chemical properties, such as, good adsorption capacity, biodegradability and possibility to be used in composites. Improving these properties is of great importance since sisal fiber may be used in various technological applications. The aim of this work was to study the influence of surface treatment on sisal fibers properties and its effect over methylene blue (MB) adsorption using kinetics models and isotherms studies. The treatment herein used was reactive microwave-assisted cold plasma using mixtures of Ar and CO2, which appears as an alternative to traditional chemical treatments. The adsorption kinetics studies were conducted in order to elucidate the behavior between adsorbent and adsorbate. For this purpose, two isotherm models were used, (i) Redlich-Peterson and (ii) Langmuir. The results show that the plasma treatment promoted an increase in fiber surface roughness, a slight and insignificant decrease in the fiber crystallinity index as well as the breaking and removal of hydroxyl groups with consequent modification of the lignocellulosic material’s original structure. The surface modification of sisal fibers by using cold plasma method promoted greater removal of the MB molecules reaching a 96 %. Kinetic and isotherm studies indicated that the adsorption mechanisms were favorable for both fibers and probably occurred in heterogeneous sites for both pristine and plasma-treated fibers. It was observed that the plasma treatment did not cause the loss of the original properties of the fibers and plays a fundamental role in increasing the adsorption, being indicated for wastewater pollutant removal processes at a low production cost as an alternative to the chemical process currently used.

Water Quality Improvement and Pollutant Removal by Two Regional Detention Facilities with Constructed Wetlands in South Texas

Stormwater runoff introduces several pollutants to the receiving water bodies that may cause degradation of the water quality. Stormwater management systems such as detention facilities and wetland can improve the water quality by removing various pollutants associated with the runoff. The objective of this research project is to determine the performance and efficiency of two major regional detention facilities (RDFs) with different designs and structures in reducing pollutants based on various storm events in McAllen, Texas. The two sites are the McAuliffe RDF and the Morris RDF; each site was incorporated with a constructed wetland with a different design and structure to enhance the pollutant removal process. The McAuliffe RDF reduced the concentration and load of many stormwater constituents in comparison to the Morris RDF. The observed concentrations and pollutant loads of suspended solids were much lower in the runoff of the inlet compared to the outlet for both sites. The McAuliffe RDF showed better concentration and load reduction for nutrients, such as nitrogen and phosphorus, of different species. However, both sites did not show a significant improvement of organic material. In addition, the indicator bacteria concentration represented a fluctuation between the inlet and outlet at each site.

Influence of filter layer positions and hydraulic retention time on removal of nitrogen and phosphorus by porous asphalt pavement.

This study was aimed to investigate the removal processes of nitrogen (TN), NH4 +-N and phosphorus (TP) from surface runoff by performing experiments on the filter layers in porous asphalt pavement (PAP). Experiments were conducted to compare the differences of the filter layer placed at the top, the middle or the bottom of PAP. The effects of retention time on the removal of the pollutants and the adsorption capacity of PAP materials were also investigated. Results indicated that the filter layer placed under the bed course improved the removal rates of pollutants compared to the other two cases on the whole. The concentration of TP in the effluent decreased by 80% after the 48 h retention time. In conclusion, this study demonstrated that the positions of filter layers and the temporary retention time of surface runoff within the bed course of PAP were critical parameters for determining the removal processes of pollutants. Thus, a certain retention time for surface runoff in bed course is of great importance for PAP to serve as an effective low impact development technology for stormwater management.

Metallic Active Sites on MoO2(110) Surface to Catalyze Advanced Oxidation Processes for Efficient Pollutant Removal.

SummaryAdvanced oxidation processes (AOPs) based on sulfate radicals (SO4⋅−) suffer from low conversion rate of Fe(III) to Fe(II) and produce a large amount of iron sludge as waste. Herein, we show that by using MoO2 as a cocatalyst, the rate of Fe(III)/Fe(II) cycling in PMS system accelerated significantly, with a reaction rate constant 50 times that of PMS/Fe(II) system. Our results showed outstanding removal efficiency (96%) of L-RhB in 10 min with extremely low concentration of Fe(II) (0.036 mM), outperforming most reported SO4⋅−-based AOPs systems. Surface chemical analysis combined with density functional theory (DFT) calculation demonstrated that both Fe(III)/Fe(II) cycling and PMS activation occurred on the (110) crystal plane of MoO2, whereas the exposed active sites of Mo(IV) on MoO2 surface were responsible for accelerating PMS activation. Considering its performance, and non-toxicity, using MoO2 as a cocatalyst is a promising technique for large-scale practical environmental remediation.

Tuning of Persulfate Activation from a Free Radical to a Nonradical Pathway through the Incorporation of Non-Redox Magnesium Oxide.

Nonradical-based advanced oxidation processes for pollutant removal have attracted much attention due to their inherent advantages. Herein we report that magnesium oxides (MgO) in CuOMgO/Fe3O4 not only enhanced the catalytic properties but also switched the free radical peroxymonosulfate (PMS)-activated process into the 1O2 based nonradical process. CuOMgO/Fe3O4 catalyst exhibited consistent performance in a wide pH range from 5.0 to 10.0, and the degradation kinetics were not inhibited by the common free radical scavengers, anions, or natural organic matter. Quantitative structure-activity relationships (QSARs) revealed the relationship between the degradation rate constant of 14 substituted phenols and their conventional descriptor variables (i.e., Hammett constants σ, σ-, σ+), half-wave oxidation potential (E1/2), and pKa values. QSARs together with the kinetic isotopic effect (KIE) recognized the electron transfer as the dominant oxidation process. Characterizations and DFT calculation indicated that the incorporated MgO alters the copper sites to highly oxidized metal centers, offering a more suitable platform for PMS to generate metastable copper intermediates. These highly oxidized metals centers of copper played the key role in producing O2•- after accepting an electron from another PMS molecule, and finally 1O2 as sole reactive species was generated from the direct oxidation of O2•- through thermodynamically feasible reactions.

Selecting and improving activated homogeneous catalytic processes for pollutant removal. Kinetics, mineralization and optimization

The degradation of a model pollutant, tartrazine, very used in food industry and usually present in WWTPs effluents and surface waters, was investigated by nine activated homogeneous catalytic processes, namely, Fe3+/H2O2, Fe2+/H2O2, UV/H2O2, UV/S2O82−, UV/Fe2+/H2O2, UV/Fe3+/H2O2, UV, VIS/Fe3+/H2O2, and VIS/Fe3+/H2O2/C2O42−. In order to compare the mineralization and oxidation ability of each process, the removal of dye, chemical oxygen demand (COD) and total organic carbon (TOC) were analyzed, as well as the overall kinetic rate constant. Also, the different oxidation path-ways (direct photolysis and/or oxidation by free radicals) were estimated for each system. After the comparison, the Fenton process, which had the highest mineralization values, was tested in luminous and dark phases using designed experiments, and the influences of all operating variables were studied by RSM.

Metabolomics Study of Subsurface Wastewater Infiltration System Under Fluctuation of Organic Load.

Subsurface Wastewater Infiltration System (SWIS) is a sewage ecological treatment technology with low investment, energy consumption, and operating cost. SWIS soil contains a large variety of microorganisms. The metabolic process and production of microorganisms are an important basis for qualitatively describing the process of pollutant removal. In order to discover the microbial decontamination pathways in SWIS, the metabolic profiles of soil microorganisms in SWIS were analyzed by UPLC-MS. Partial least squares-discriminant analysis (PLS-DA)and principal component analysis (PCA) pattern recognition methods were used to classify the samples. According to the model's variable importance factor (VIP value), potential biomarkers were screened and biological information contained in the metabolites was also analyzed. The correlation between metabolites and environmental factors was explored by RDA analysis. In total, 230 differential metabolites with VIP value greater than 1.5 were screened out when the influent organic load fluctuated at 250mgL-1, 400mgL-1, and 500mgL-1. After identifying and screening, 35 differential metabolites were identified and used to further analyze the metabolic pathway. It turns out that microbial metabolites in SWIS were mainly glycosides, fatty acids, amino acids, pigments, diterpenoids, and some polymers under medium and high organic loading conditions. At low organic load, the microbial metabolites in SWIS were mainly ketones, alcohols, and esters.

Mo0 and Mo4+ bimetallic reactive sites accelerating Fe2+/Fe3+ cycling for the activation of peroxymonosulfate with significantly improved remediation of aromatic pollutants.

In Fe2+/peroxymonosulfate (PMS) activation system, the slow cycle rate of Fe3+/Fe2+ has been considered to be the limiting step in the remediation of organic contaminants. In this paper, commercial molybdenum (Mo) powder is employed as the cocatalyst in Fe2+/PMS system, which can significantly accelerate the Fe3+/Fe2+ cycling efficiency by the exposed bimetallic active sites of Mo4+ and Mo0, and the process is accelerated as the amount of Mo powder increased. The Mo cocatalytic Fe2+/PMS system exhibits an enhanced performance for the activation of PMS and the removal of different aromatic pollutants including dyes, phenolic pollutants and antibiotics, in a wide pH range of 4.0-9.0. Importantly, Mo powder exhibits excellent cycle performance in the PMS activation system, and rhodamine B (RhB) can be removed within 10min even after 5 cycles. Electron paramagnetic resonance (EPR) prove that the sulfate radicals (SO4-) is the major reactive oxides species in the PMS activation, the increase of Fe2+ content induced by the cocatalytic effect of Mo powder can effectively promote the production of SO4- and increase the utilization of PMS. In addition, to observe the process of pollutant removal more intuitively, HPLC-MS is used to analyze the decomposing pathway of RhB and sulfadiazine in Mo+FeSO4+PMS system. It is believed that this research provides a new idea for the efficient activation of PMS by iron ions in a wide initial pH range, which is expected to be applied to the treatment of large-scale industrial wastewater.

Stirring-ageing technique to develop zirconium-pillared bentonite clay along with its surface profiling using various spectroscopic techniques

The pillared clays are getting wide attention due to the easiness in tailoring their surface for customized applications. In our laboratory, we have adopted a novel synthetic route to pillar zirconium species within intercalation spaces of bentonite clay through stirring-ageing technique and prepared the zirconium-pillared bentonite clay (ZPBC). A series of experiments conducted to optimize the stirring-ageing time span revealed that 2–4 h span is sufficient for getting a good yield of ZPBC. The synthesized ZPBC was characterized using certain well-developed sophisticated techniques to obtain their physical, structural and morphological properties. The high surface area 109 m2 g−1 noticed for ZPBC is suitable in retaining the chemical moieties of special interest during pollutant removal processes. X-ray fluorescence studies revealed that there is an increase in wt% of Zr (4.76%) in pillared clay compared to Na-bentonite which indicates that Zr has been successfully loaded on the surface of parent clay during pillarization. The mineralogical composition and the gradual changes in the interlayer spacing of parent and pillared clay are well established using X-ray diffraction technique. The Raman spectrum identifies changes in the lattice vibration modes of ZPBC as pillaring takes place. The surface topographical changes that occurred in clay after modification were revealed from the scanning electron microscopy images. The prepared ZPBC were tested successfully for the removal of phosphate from aqueous solution and obtained a maximum adsorption capacity 58.83 mg g−1 at 30 °C.

Potential of water fern (Azolla pinnata R.Br.) in phytoremediation of integrated industrial effluent of SIIDCUL, Haridwar, India: removal of physicochemical and heavy metal pollutants

Integrated industrial effluent (IIE) released from SIIDCUL causes serious environmental problems in the vicinity of Haridwar, India. Therefore, this study investigated the potential of water fern (Azolla pinnata R.Br.) for phyto-treatment of IIE. Laboratory experiments with six IIE concentrations (0 as control with bore well water, 20, 40, 60, 80 and 100%) were performed for bio-removal of selected physicochemical, microbiological and heavy metal parameters of IIE in pot type experiments. The overall results described maximum removal of physico-chemical (pH, EC, TDS, BOD, COD, TKN, Ca, Mg, Na, K), microbiological (MPN and SPC) and heavy metals (Cd, Cu, Cr, Fe, Pb, Mn, and Zn) parameters in 60% concentration of IIE, respectively. The stimulus effect of IIE concentration on pollutant removal process was confirmed using Kruskal–Wallis post hoc test, one way ANOVA (p < 0.05), and linear regression (R2 < 0.85) tools. Besides this, A. pinnata relative plant growth rate was also maximum in 60% IIE treatment. This is the first report on phytoremediation of IIE while findings of this study showed that A. pinnata was useful for the eco-friendly treatment of SIIDCUL IIE and could minimize potential wastewater management issues.

Electro-crystallized SnO2 nanoparticles for river-water heavy-metal ion pollutant removal process

SnO2 nanoparticles were electro-crystallized in an electrochemical cell containing two tin electrodes, and an electrolyte solution of C4H12Cl and the effect of growth conditions has been studied on their structural properties. The XRD patterns confirmed the formation of tetragonal tin dioxide at 700 °C. SEM images showed the mean particle size ranges from 12 to 35 nm, depending on growth conditions. The particles synthesized at 25 V, 55 °C, and 0.004 M with mean size of about 12 nm are the smallest particles. The band gap of SnO2 nanoparticles is found to be 4.2 eV. The removal of cobalt and cadmium from laboratory water and Seimareh and Karoon rivers in Iran has been investigated. The results showed that in the optimal removal conditions; 10 V, pH of 13, initial heavy metals’ concentration of 100 mg/L and reaction time of 30 and 50 min, the removal efficiency of cadmium and cobalt is 100% and 99.95%, respectively.

Effects of layered combined substrates on plant growth and treatment performance and its spatiotemporal variation of vertical-flow constructed wetlands.

Layered combined bio-ceramic, zeolite, and anthracite were used as substrates in vertical-flow constructed wetlands (VFCWs) for enhancing contaminant removal from synthetic municipal wastewater. Plant growth and propagation and the removal of organic matter, nitrogen, and phosphorus as well as its spatiotemporal variation were evaluated systematically. The results demonstrated that three different substrates were adequate for the establishment of Canna indica L., especially for zeolite. All small-scale VFCW units were simultaneous efficient in removing CODCr (73.9-78.7%), NH4+-N (83.8-89.9%), TN (88.3-91.5%), SRP (93.8-98.6%), and TP (87.1-90.9%) with a little significant difference on treatment performance. Different pollution removal processes followed a different trend because of their different removal mechanisms driven by the synergy of substrate, plant, and microorganism. Purification space moved down due to the adsorption capacity consumption of upper layer substrate over time. It was concluded that VFCWs filled with layered combined bio-ceramic, zeolite, and anthracite had great potential for treating municipal wastewater.

Assessment of pollutant removal processes and kinetic modelling in vertical flow constructed wetlands at elevated pollutant loading.

Constructed wetland (CW), an ecological wastewater treatment technology, is low cost and easily to operate. Vertical flow constructed wetland (VF-CW) systems have been used to treat various wastewaters across the world. The present work exhibits the detail study of five type's multi-layered vertically constructed wetlands operated at 24h hydraulic retention time under semi-continuous vertical flow mode. Except N-NO3-, all the pollutants were sufficient removal in iron scraps constructed wetland (ISs-CW). The highest average pollutant removal efficiency achieved in ISs-CW was 85.04%, 77.57%, 85.99%, 62.01% and 88.91% for N-NH4+, N-NO2+, total nitrogen, total phosphate and sulphate respectively. The present CWs planted with Eichhornia crassipes is a promising system for municipal wastewater treatment. The first-order kinetic modelling was best suited for the removal rate since it presents higher R2, rate constant (k) and B values.