Wastewater Treatment Methods Research Articles

Application of FeOOH nanorods as a heterogeneous Fenton catalyst: The Matter of aspect ratio

Due to the growing global population and shift towards industrialized societies, water pollution and the management of wastewater are becoming significant issues. Hence, there is a need for innovative approaches to remove contaminants from effluent streams to protect the environment and human health. The Fenton's reaction is an established method for wastewater treatment, and iron oxide hydroxide (FeOOH) nanorods have immense potential as heterogeneous Fenton catalysts. The catalytic potency of nanorods is determined by their morphology, especially their length. Therefore, this study aimed to synthesize FeOOH nanorods of different mean lengths (49–101 nm) and evaluate their catalytic activity in a Fenton's reaction. Nanorods with an average length of 78 nm had the highest catalytic activity, and 87% of methyl orange was degraded over the reaction. The greater catalytic activity of these nanorods can be attributed to their larger surface area compared to the other investigated sizes. FeOOH nanorods have a porous structure; thus, their surface area is not directly related to their particle size. These outcomes indicate that the porosity and surface area play a significant role in determining the performance of heterogeneous catalysts and, as a result, must be considered to develop efficient catalysts for environmental remediation.

Treatment of wastewater containing thallium(I) by long-term operated manganese sand filter: Synergistic action of MnOx and MnOM

The long-term and stable removal of thallium (Tl) from industrial wastewater generated by mining and smelting operations remains challenging. While sand filters are commonly applied for the simultaneous removal of Mn(II) and other heavy metals, they have limited efficacy in treating Tl-contaminated wastewater. To address this gap, we operated a lab-scale Mn sand filter (MF) without added microorganisms to investigate the efficiency and mechanisms of Mn(II) and Tl(I) removal. Trends in effluent Mn(II) and Tl(I) concentrations indicated three operational stages: start-up, developing and maturation. Over time, the removal efficiency of Tl(I) gradually improved, plateauing at approximately 80 % eventually. Throughout operation, Tl(I) was sequestrated via surface complexation and ion exchange. Besides, enrichment of Sphingobium and other typical manganese oxidizing microorganisms (MnOM) during operation facilitated Mn(II) and Tl(I) oxidation and sequestration by generating biogenic manganese oxides (BioMnOx). Additionally, the accurate control of water quality and operating conditions during operation could also enhance removal efficiency. In summary, physicochemical actions of Mn oxides and biochemical actions of microorganisms synergistically contributed to the sequestration of Mn(II) and Tl(I). These findings provided a novel and sustainable method for the long-term and stable treatment of industrial wastewater containing thallium.

Efficient wastewater treatment in petroleum refineries: Hybrid electro-fenton and photocatalysis (UV/ZnO) process

In this study, a new hybrid system composed of a photo-catalysis (UV/ZnO) process combined with an electro-Fenton (EF) process equipped with a micro porous graphite air diffusion cathode (MPGADC) was used to treat petroleum refinery wastewater (PRW). The hybrid system was operated in a batch recycle mode and its performance was investigated and optimized using a response surface methodology (RSM). Three operating parameters affecting on the removal efficiency (RE%) of chemical oxygen demand (COD) were investigated including current density (2–10 mA/cm2), ZnO dosage (0.05–0.35 g/L), and Fe2+concentration (0.05–0.15 mM). Results showed that the optimum operating conditions can be achieved using a current density of 6.44 mA/cm2, with ZnO dosage of 0.35 g/L, and concentration of Fe2+ ions at 0.05 mM in which RE% of 90.15% was obtained with requiring a total electrical energy consumption (EECT) of 19.102KWh/m3. Furthermore, analysis of variance (ANOVA) exhibited a high value of determination coefficient (R2) close to 98.24% indicating a satisfactory fit between the obtained regression model and the experimental results. Moreover, ANOVA results revealed that current density has the most significant effect on RE% with a contribution of 52.41% followed by ZnO dosage and Fe2+ concentration both of them with a contribution of 11.64%. The comparison between the individual photo-catalysis process and hybrid process showed that RE% increases from 77.83% to 90.15% making an enhancement by 15.83% in RE% while EECT decreased from 27.171to 19.102KWh/m3 making a reduction by 29.7% in EECT. Hence, combining EF with photo-catalysis process improves the efficiency and reduced the required energy in comparison with the individual photo-catalysis process. Therefore, the combined process could be considered as an alternative, sustainable, green and cost-effective method for treatment of refinery wastewaters.

Enhancement of alkali- and oxidation-modified biochars derived from water hyacinth for ammonium adsorption capacity

ABSTRACT Wastewater containing high concentrations of ammonium-nitrogen (NH4 +-N) is considered a major concern because its untreated discharge has a variety of adverse effects on the environment and human health. Adsorption using biochars is an easy and cost-effective wastewater treatment method. However, aquatic plants such as water hyacinth for biochar feedstock are considered unsuitable for adsorbent use due to limited NH4 +-N adsorption capacity. In this study, biochar made from water hyacinth was modified with potassium hydroxide (KOH) and hydrogen peroxide (H2O2) to obtain highly efficient adsorbent. This study aimed to enhance NH4 +-N adsorption capacity by KOH- and H2O2-treatments and identify NH4 +-N adsorption mechanism of the modified biochars derived from water hyacinth. The NH4 +-N adsorption of all biochars was dependent on the initial solution pH increasing from pH 2 to 4, then relatively constant from pH 4 to 8. Pseudo-second-order model and Langmuir model were found to be the best fit for NH4 +-N adsorption data. The maximum NH4 +-N adsorption capacity of biochars increased about 8 times (17.1 mg g−1) and 10 times (21.5 mg g−1) after KOH- and H2O2-modification, respectively, compared to pristine biochar (2.14 mg g−1). The main NH4 +-N adsorption mechanisms were suggested as cation exchange for both biochars particularly KOH-modified biochar, and hydrogen bonding by oxygen-containing surface functional groups for H2O2-modified biochar. This study suggested that aquatic plant-based biochar, which has been considered difficult to use, had potential as a promising alternative adsorbent for removing NH4 +-N from wastewater through modification.

Estimating ammonium changes in pilot and full-scale constructed wetlands using kinetic model, linear regression, and machine learning

Constructed wetlands (CWs) are a widely utilized nature-based wastewater treatment method for various effluents. However, their application has been more focused on pilot and full-scale CWs with substantial surface areas and extended operation times, which hold greater relevance in practical scenarios. This study used kinetics, linear regression (LR), and machine learning (ML) models to estimate effluent ammonium in pilot and full-scale CWs. From screening 1476 papers, 24 pilot and full-scale CW studies were selected to extract data containing 15 features and 975 data points. Nine models were fit to this data, revealing that linear models were less effective in capturing CW effluent compared to nonlinear ML algorithms. For training data, the Monod kinetic model predicted the poorest performance with an RMSE of 41.84 mg/L and R2 of 0.34, followed by simple LR (RMSE 24.29 mg/L and R2 0.77) and multiple LR (RMSE 22.63 mg/L and R2 0.80). In contrast, Cubist and Random Forest achieved high performances, with an average RMSE of 12.01 ± 5.38 and an average R2 of 0.93 ± 0.07 for Cubist, and an average RMSE of 15.94 ± 10.69 and an average R2 of 0.91 ± 0.08 for RF. The trained Random Forest performed the best for new data, with an R2 of 0.93 and RMSE of 13.48 mg/L. This ML-based model is a valuable tool for efficiently estimating effluent ammonium concentration in pilot and full-scale CWs, thereby facilitating the design of systems.

Application of electrocoagulation process for the treatment of reactive blue 19 synthetic wastewater: Evaluation of different operation conditions and financial analysis

The aim of this study was to treat reactive blue 19 (RB 19) in solution by electrocoagulation (EC) process, using aluminum cathodes modified by zinc oxide nanoparticles (ZnO-NPs). Cyclic voltammetry methodology (CVM) was used to investigate the effect of coating aluminum electrodes with ZnO-NPs. The response surface methodology (RSM) based on central composite design (CCD) and analysis of variance (ANOVA) were used to evaluate and optimize the variables and the response, which was dye removal efficiency. The economic and energy analyses confirmed that this process was a promising method for pretreatment and treatment of industrial textile wastewater.

Design peculiarities and mathematical model of an enhanced low-frequency vibratory cavitation device

The thorough analysis of the technological processes used to purify the wastewater from food and processing enterprises (bakery, brewery, coffee, sugar, beverage, etc.) has established that among the most effective processes are the physical ones. From the wide range of physical methods of wastewater treatment, the cavitation treatment methods are of the most promising from the viewpoint of industrial application. The present paper considers an enhanced design of a low-frequency vibratory cavitation device with an electromagnetic drive. Unlike many other cavitators of ultrasonic or hydrodynamic action, the proposed vibratory cavitation device can treat the wastewater in a continuous liquid flow, has no rotating components and parts, which significantly increases its reliability and durability, and can be equipped with changeable concaves (grates) depending on the pollutants to be purified. The research methodology consists of two main stages: development of the dynamic diagram and mathematical model of the considered cavitation device; numerical simulation of the working members vibrations at different operational conditions. The obtained results are presented in the form of time dependencies of the concaves (grates) displacements, speeds, and accelerations under various viscous friction and excitation parameters. The main scientific novelty of this study, in addition to the improved design of the vibratory cavitator, is considering the influence of the changeable electromagnetic excitation force and viscous friction force on the dynamic behavior of the concaves (grates). Further investigations on the present topic can be focused on the practical implementation and experimental testing of the proposed cavitation device in order to increase the water purification degree.

New isostructural ZIFs for adsorption of crystal violet

Adsorption is considered an economical method for wastewater treatment due to its simple process, low cost of application and operation, and the fact that it does not require any additional pre-treatment. In this study, we have successfully synthesised two new isostructural zeolitic-imidazolate frameworks (ZIFs) with the purpose of utilising them as adsorbents for the removal of crystal violet (CV). Two isostructural ZIFs, namely ZIF-101 and ZIF-201, are consist of two different types of imidazolate-based linkers that are coordinated with different tetrahedral metal ions (Zn2+ and Co2+) to form a three-dimensional extended network with a cag topology. The products were characterised using single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), nuclear magnetic resonance (1H NMR), and fourier transform infrared (FTIR) spectroscopies. The two isostructural ZIFs, ZIF-101 and ZIF-201, crystallised in the identical space group and crystal system. It was discovered that the optimal conditions for CV adsorption were found to be at an initial CV concentration of 20 mg/L and an adsorbent dosage of 5 mg at neutral pH. The adsorption of CV using isostructural ZIFs fitted well with the pseudo-second-order kinetic model, and the best adsorption isotherm for this study is the Langmuir model, which proved that the adsorption of CV occur on the homogeneous surface of adsorbents. The maximum adsorption capacities using ZIF-101 and ZIF-201 are 7.86 mg/g and 10.83 mg/g, respectively.

Ecofriendly Synthesis of Magnetic Composites Loaded on Rice Husks for Acid Blue 25 Decontamination: Adsorption Kinetics, Thermodynamics, and Isotherms.

Addressing the growing need for methods for ecofriendly dye removal from aqueous media, this study explores the potential of rice husks coated with iron oxide (Fe2O3@RH composites) for efficient Acid Blue 25 decontamination. The adsorption potential of Acid Blue 25 is analyzed using raw rice husks and Fe2O3 nanoparticles in the literature, but their enhanced removal capacity by means of Fe2O3@RH composites is reported for the first time in this study. Fe2O3@RH composites were analyzed by using analytical techniques such as TGA, SEM, FTIR, BET, and the point of zero charge (pH(PZC)). The Acid Blue 25 adsorption experiment using Fe2O3@RH composites showed maximum adsorption at an initial concentration of Acid Blue 25 of 80 ppm, a contact time of 50 min, a temperature of 313 K, 0.25 g of Fe2O3@RH composites, and a pH of 2. The maximum percentage removal of Acid Blue 25 was found to be 91%. Various linear and nonlinear kinetic and isothermal models were used in this study to emphasize the importance and necessity of the adsorption process. Adsorption isotherms such as the Freundlich, Temkin, Langmuir, and Dubinin-Radushkevich (D-R) models were applied. The results showed that all the isotherms were best fitted on the data, except the linear form of the D-R isotherm. Adsorption kinetics such as the intraparticle kinetic model, the Elovich kinetic model, and the pseudo-first-order and pseudo-second-order models were applied. All the kinetic models were found to be best fitted on the data, except the PSO model (types II, III, and IV). Thermodynamic parameters such as ΔG° (KJ/mol), ΔH° (KJ/mol), and ΔS° (J/K*mol) were studied, and the reaction was found to be exothermic in nature with an increase in the entropy of the system, which supported the adsorption phenomenon. The current study contributes to a comprehensive understanding of the adsorption process and its underlying mechanisms through characterization, the optimization of the conditions, and the application of various models. The findings of the present study suggest practical applications of this method in wastewater treatment and environmental remediation.

N-doped citrate-sludge-derived carbon (NCSC) effectively promotes peroxymonosulfate activation for perfluorooctanoic acid (PFOA) removal with surface-mediated electron transfer mechanism

In traditional wastewater treatment methods, the removal of emerging contaminants including perfluorooctanoic acid (PFOA) can be challenging. To address this, biochar is commonly utilized as an activator for peroxymonosulphate (PMS) to effectively eliminate organic pollutants. Sewage sludge has shown potential as a biochar precursor, but its complex composition and variable iron content, as well as the low specific surface area of the product limit the practical use of iron-dominated sludge-derived catalysts. To overcome this limitation, N-doped citrate-sludge-derived carbon (NCSC) was synthesized, possessing a low iron content (0.29 at%) and a large specific surface area (315.31 m2 g−1). As a comparison, Fe-/N-doped citrate-sludge-derived carbon (Fe-NCSC) was prepared by introducing exogenous iron, resulting in a higher iron content (2.12 at%) but a significantly reduced specific surface area (73.87 m2 g−1). In performance evaluation, the NCSC/PMS system achieved impressive removal efficiency, effectively eliminating 99.8% of PFOA (at an initial concentration of 2 mg L−1) within 60 min, while Fe-NCSC/PMS only achieved 84.6%. The slightly lower reaction rate per specific surface area of NCSC/PMS proved that large specific surface area was NCSC’s key advantage. The lower sensitivity of NCSC to pH and water substrates than FeNCSC suggested different activation mechanisms. Further analysis of reactive sites and species showed that the main oxidation mechanism of NCSC/PMS was forming the surface-bound PMS-NCSC complexes at the N sites, followed by PFOA donating electrons to the complexes to be oxidized, which was different from the Fe/N-dominated singlet oxygen mechanism of Fe-NSC/PMS. Furthermore, the reusability of the NCSC was demonstrated, with the removal rate decreasing to only 90.1% after four cycles and recovering to 94.8% after heated regeneration. In conclusion, this study provides a viable method for the elimination of emerging contaminants such as PFOA in water remediation.

A fungal-algal self-flocculation system and its application to treat filter sludge leachate in the sugar industry

The efficient and economical treatment of wastewater using microalgae has attracted much attention. However, harvesting microalgae cells from treated wastewater remains challenging. In the present study, a Chlorella vulgaris suspension containing filamentous fungi Aspergillus niger and Chaetomium gracile was successfully used to construct a self-flocculating system, with a microalgae flocculation efficiency of 99.6% achieved by gravity sedimentation within 4 h. The diameter of fungi played an important role in determining flocculation efficiency, and the optimal particle size was 10 mm. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) results indicated that the sweeping action of fungal mycelia and the interaction between the functional groups of fungi and the C. vulgaris surface contributed to improve flocculation. Co-cultivation of C. vulgaris and fungi could effectively remove 83.53%, 94.45% and 76.88% of total phosphorus, total nitrogen and chemical oxygen demand, respectively, from the sludge leachate from a sugar mill. The fungal-algal biomass reached 5.75 g/L. Herein, the constructed self-flocculation system had coupled efficient flocculation of C. vulgaris with removal of pollutants from wastewater in a short period of time, and providing a green, pollution-free, low-cost method for simultaneous wastewater treatment and the production of high quality biomass.

Promoting Effect of Silver Oxide Nanoparticles on the Oxidation of Bisphenol B by Ferrate(VI).

Bisphenol B (BPB, 2,2-bis(4-hydroxyphenyl) butane), as a substitute for bisphenol A, has been widely detected in the environment and become a potential threat to environmental health. This work found that silver oxide nanoparticles (Ag2O) could greatly promote the removal of BPB by ferrate (Fe(VI)). With the presence of 463 mg/L Ag2O, the amount of Fe(VI) required for the complete removal of 10 μM BPB will be reduced by 70%. Meanwhile, the recyclability and stability of Ag2O have been verified by recycling experiments. The characterization results and in situ electrochemical analyses showed that Ag(II) was produced from Ag(I) in the Fe(VI)-Ag2O system, which has a higher electrode potential to oxidize BPB to enhance its removal. A total of 13 intermediates were identified by high-resolution mass spectrometry, and three main reaction pathways were proposed, including oxygen transfer, bond breaking, and polymerization. Based on the toxicity assessment through the ECOSAR program, it is considered that the presence of Ag2O reduced the toxicity of BPB oxidation intermediates to aquatic organisms. These results would deepen our understanding of the interaction between Fe(VI) and Ag2O, which may provide an efficient and environmentally friendly method for water and wastewater treatment.

Fabrication of Bi/BiOCOOH/PVDF with improved photocatalytic activity for the degradation of ciprofloxacin

The development of a low-cost and recyclable method for wastewater treatment has been a major challenge. Polyvinylidene fluoride (PVDF) membranes have received considerable attention owing to their excellent mechanical strength, unique antioxidant properties, and low cost. In this study, Bi/BiOCOOH/PVDF composite membrane materials were prepared using a simple two-step solvent thermal method and phase conversion method. The results showed that under the synergistic action of adsorption and photocatalysis, the photocatalytic degradation efficiency of Bi/BiOCOOH composite material and Bi/BiOCOOH/PVDF composite membrane material for ciprofloxacin (CIP) was much higher than that of BiOCOOH. The introduction of PVDF acted as a carrier, improved the adsorption of the catalytic material to CIP, and facilitated the effective collision of the photocatalytic active site and CIP. The experimental results and theoretical calculations confirmed that the combination of Bi and BiOCOOH effectively improved the light absorption capacity and photocatalytic performance. The reproducibility test revealed that the small amount of new composite catalyst for Bi/BiOCOOH/PVDF as a carrier was lost and that the Bi/BiOCOOH/PVDF catalyst still had high catalytic activity. In addition, the influence of water matrix factors, such as pH and anion, on the photocatalytic degradation experiment was investigated, which would provide some reference for the actual wastewater treatment of the composite catalyst. This study demonstrates a photocatalytic activation mechanism between metals and semiconductors and provides some basis for constructing catalysts for the synergistic and effective treatment of water pollution through a combined adsorption and photocatalysis process.

RSM Optimization of Direct Orange 26 Adsorption on Low-Cost Silica Fume Adsorbent

Today, dye pollutants enter resources of water through various industries. Due to the stability and carcinogenicity of dye pollutants, it is necessary to treat colored wastewater before entering the aqueous cycle. One of the important methods for wastewater treatment is adsorption. In this study, the effect of industrial waste of silica fume adsorbent on azo dye Direct Orange 26 (DO26) was investigated. Design of experiment was carried out with CCD method by using Design Expert software version 7 to model and investigate the effects of parameters pH, concentration, amount of adsorbent, and time. The model proposed by the software is a second-order model. According to the findings, important and effective parameters for the quadratic model of experimental design were obtained from ANOVA (analysis of variance). The optimum conditions for the maximum removal of DO26 (95.26%) were obtained to be at pH 2.01, contact time of 55.15 minutes, adsorbent amount of 0.2 g, and initial concentration of 44 ppm. The experimental kinetic data were analyzed through the conventional kinetic models, and the results demonstrate that the sorption kinetics can be accurately described by the pseudo-second order model. Also, based on FESEM image, silica fume has a spherical and porous structure, therefore, silica fume can remove dye pollutants from water as a cheap adsorbent.

Bioelectricity Generation from Microbial Fuel Cell utilizing Sewage Wastewater and Cow Urine from Dutse Metropolis Jigawa State

Microbial fuel cells (MFCs) are technologies that directly transform chemical energy into electrical energy by oxidizing organic matter using bacteria as biocatalysts. MFCs offer a potential technology for converting wastewater into useful energy source and at the same time serve as wastewater treatment facilities. This makes it superior to other wastewater treatment methods. This study focused on the utilization of MFCs to generate bioelectricity from sewage wastewater using cow urine as inoculum and identify the bacteria colonizing the anode electrode. The experiment were conducted using two-chambered MFC constructed using locally sourced materials. Wastewater was characterized using standard methods. The characteristics of the sewage wastewater are: 680 mg/L Chemical oxygen Demand (COD), 457 mg/L Biochemical oxygen Demand (BOD) and pH of 7.4. The maximum voltage, power and current density obtained were 196 mV, 18.26 mW/m2 and 97 mA/m2 respectively. The MFC shows a reduction in COD value by 82 % (680mg/L initial and 120 mg/L final).The identification of the anodic biofilms showed the presence of Bacillus spp and klebsiella spp based on their microscopic and biochemical characterization. The results of this study can contribute to improve understanding and optimizing electricity generation in MFC, Further study would be conducted in order to identify the microorganisms at molecular level.

Hybrid heterogeneous decontamination of polluted organic effluents using tailoring Fe2O3-ZnO over rGO via cutting-edge cold plasma technology

Regarding limited drinking water resources and also increasing pollution production rate from various industries, wastewater treatment methods have attracted considerable attention. Herein, sono-photodegradation of methylene blue (MB) was investigated over plasma-treated Fe2O3-ZnO/rGO (denoted as Fe2O3-ZnO/rGO (P)). Characterization of the photocatalysts was evaluated by XRD, FESEM, EDX, HRTEM, SAED, BET-BJH, DRS, and PL analyses. The defects, revealed by SAED, are related to thermal reduction and residual functional groups on rGO sheets. TEM and dot-mapping analysis showed considerable enhancement in the distribution of active phases on rGO. Furthermore, plasma treatment enhanced the contact area between nanoparticles and rGO sheets. BET-BJH represented Fe2O3-ZnO/rGO (P) as a mesoporous composite appropriate for degradation reaction. Moreover, the specific surface areas were 77 and 63 m2/g and total pore volumes were 109 and 84 cm3/g, for Fe2O3-ZnO/rGO and Fe2O3-ZnO/rGO (P) catalysts, respectively. The reason is that large clusters on the surface have been crushed and consequently blocked micropores. Due to more contact area in the plasma-treated sample, the recombination of photoinduced charges was declined, as in the condition of 20 mg/L initial MB concentration and 1g/L catalyst dosage, degradation reached from 83.4 to 97.5 %. Furthermore, plasma treatment caused a faster shift of the photogenerated charge into the graphene lattice. Plasma-treated Fe2O3-ZnO/rGO showed good reusability and degradation was 89.3 % after 5 runs.

The performance and microbial community of anaerobic membrane bioreactor for high calcium papermaking wastewater treatment

High calcium papermaking wastewater challenges anaerobic biological technology applications, leading to sludge calcification and unstable reactor operation. This study employed an anaerobic membrane bioreactor (AnMBR) to treat high-calcium papermaking wastewater (1000 mg/L) and achieved an average chemical oxygen demand removal efficiency of 90.1%. No significant accumulation of volatile fatty acids was observed during the entire experimental period. The methane production capacity decreased with the increasing inlet calcium ion concentration, and the maximum methane production rate in Stage 4 was 115.4 mL·(gVSS·d)−1. The maximum transmembrane pressure reached was 4.33 kPa, and the sludge was primarily present in the form of flocs due to the hydraulic shear effects. Anaerolineaceae, Bacteroidetes_vadinHA17, Methanosaetaceae and Methanobacteriaceae were identified as the dominant bacterial species in Stage 4, correlating with the robust anaerobic digestion performance. In conclusion, the AnMBR exhibited a reliable and effective treatment method for high calcium papermaking wastewater.

OXIDATION METHODS FOR PHENOLE-CONTAINING WASTEWATER TREATMENT

One of the most complex environmental problems generated by the development of human economic activity is the problem of the negative impact of chemically polluted territories on the objects of the hydrosphere. A lot of toxic compounds, getting into water reservoirs, cause the water area deterioration, the death of their flora and fauna, make the water unusable either for drinking nor for cultural and household needs. Recently, the attention of specialists has been attracted by a group of persistent organic pollutants. All these substances belong to the class of organochlorine pollutants, as well as by-products of hydrocarbon production (for example: dioxins, furans, formaldehydes, phenols). These substances are resistant to decomposition and toxic. Among the most dangerous water pollutants, along with heavy metal ions, petroleum products, surfactants and polyaromatic compounds, are phenol and its derivatives. Phenol-containing wastewater is generated at enterprises of the pulp and paper, woodworking, food industries, leather, chemical, coke, petrochemical industries, etc. When even a small amount of phenolic compounds gets into a water body, the reservoir self-cleaning capacity decreases. In this regard, the problem of an objective assessment of hydrosphere pollution by phenols and its derivatives and the search for new effective methods of wastewater treatment are urgent tasks. The paper describes oxidation methods for wastewater treatment from phenol.

Gerçek Tekstil Atıksularının Perovskite/Aktif Karbon Kompozit Katalizör Varlığında Elektrokoagülasyon ve Fenton Benzeri Oksidasyondan Oluşan Hibrit Sistem Kullanılarak Son Arıtımı

A hybrid wastewater treatment method was used to improve the quality of the treated wastewater for possible reuses. Real textile wastewater was subjected to electrocoagulation and Fenton like oxidation sequentially. In the Fenton like oxidation process the performances of BiFeO3/RHAC and BiNiO3/RHAC (RHAC: Rice husk based activated carbon) catalysts were compared. BiNiO3/RHAC was determined to be more effective in total organic carbon removal. A parametric study was carried out in the presence of the selected BiNiO3/RHAC catalyst to investigate the effect of the catalyst loading, pH and the oxidant dosage on total organic carbon removal. The most suitable reaction conditions were determined as 1.5 g/L of catalyst loading, pH 7, and 2 mM initial hydrogen peroxide concentration. 17% and 15.7% total organic removal efficiencies were achieved in electrocoagulation and Fenton like oxidation processes, respectively, whereas the cumulative removal efficiency was 32.7%.

The Potential of Ozone/UV System in The Treatment of Batik Wastewater in Indonesia

The Batik dyeing method, producing famous fabric products recognized locally and internationally, requires lots of wax and dyes in the dyeing process. The wastewater containing high loads of organic pollutants requires proper treatment to prevent environmental damage. Among many technologies developed for wastewater treatment, combining ozonation and UV irradiation has been a promising method due to its effectiveness in degrading and reducing the organic pollutants in wastewater. In this study, Batik wastewater was treated using commercially available ozone generators and UV lamps in a combined ozone/UV system to confirm the effectiveness and to propose a simple and economically feasible method for Batik wastewater treatment. The color and the suspended solids in the wastewater were reduced significantly after 48-hour treatment using the setup in this study. A simple simulation of the investment and operational costs was also conducted.