Optimizing potassium ferrate for textile wastewater treatment by RSM

: This study examines the efficiency of photodegradation process (color and COD removal) in textile wastewater treatment, using copper oxide nanoparticles (CuO-NPs) as photocatalyst to propose a suitable alternative for the available approaches. The experiments were developed, using a central composite design and response surface methodology (RSM). RSM was applied to evaluate the effects of different variables, including pH, CuO- NPs concentration, reaction time, and UV light intensity, as well as their interactions for achieving optimal conditions. The second-order model consisted of linear and quadratic terms, which seemed appropriate for color and COD removal. All the variables showed significant effects on color and COD degradation. The optimal conditions for maximum color degradation (83%) included pH of 6.9, contact time of 60 min, CuO- NPs concentration of 0.05 g/L, and UV light intensity of 30 W. In addition, the optimal conditions for maximum COD reduction (99%) were pH of 6.8, contact time of 60 min, CuO-NPs concentration of 0.02 g/L, and UV light intensity of 30 W. Based on the results of this study, CuO-NPs can be used for effective treatment of textile wastewater by high COD and color removal.

Optimization and analysis of homogenous Fenton process for the treatment of dry-spun acrylic fiber manufacturing wastewater

Biodegradation of Olive Mill Wastewater by a newly isolated novel bacterial consortium under RSM optimized culture conditions

In this study, electron beam accelerator (EB) was used to treat textiles wastewater from Rawang Industrial Park, Selangor. The objectives were to determine effective energy, beam current and absorbed dose required for decoloration and degradation of the textiles effluent. The textiles effluent was irradiated in a batch with various energy of 1MeV to 3MeV at constant beam current of 30mA. It was observed that removal of color and COD increases with higher beam energy. The EB energy of 1MeV effectively to removed 58% color and 19% COD. For textile effluent sample irradiated at fix energy of 1MeV and 3Mev but at different beam current 10mA, 20mA and 30mA. It was observed that removal of color and COD increases with the increased of beam current at each energy. However removal of color was significantly better at 1Mev as compared to 3Mev. In the case of textiles effluent, irradiated at doses of 17, 20,25,30, 35, 100 and 200kGy using 30 kW power of EB (1Mev, 30mA), results shows removal of BOD5, COD and color were in the range 9%-33%, 14%-38% and 43%-78% respectively.

Catalytic ozonation is one of the promising treatment methods for removal of persistent organic compounds from water and wastewater. In this study, some metal slags such as: iron slag, lead slag, zinc slag, cadmium slag and copper slag originated from solid waste of Thai Nguyen Non-ferrous Metals Limited Company, Vietnam were used as heterogeneous catalysts for ozonation process to remove organic compounds from pulp wastewater. The effects of the initial pH (pHi) of pulp wastewater and the metal slag dosage on efficiency of decolorization and mineralization of pulp wastewater, in term of COD were investigated. The results indicated that iron slag was the most suitable catalyst for treatment of pulp wastewater by ozonation process with the highest removal efficiency of COD, namely, after 120 min of ozonation (with flowrate of O3 of 3.038 g/h) of the pulp wastewater (initial COD 1809 mg/L), COD removal efficiency, respectively, reached 91,16%; 84%; 83,83 %; 83,91%; 83,41% and 83,14% in the presence of iron, copper, zinc, lead, cadmium slag and ozone alone. Simultaneously, the color was almost completely removed (95.55 – 98.79%) by ozonation processes with using all before-mentioned metal slags as heterogeneous catalysts and ozone alone. Maximum COD and color removal efficiency obtained at pH 7 for ozonation alone and its combinations with iron slag. Moreover, an increase in the iron slag dosage from 0.125 g/L to 2.0 g/L for O3/iron slag could enhance COD and color removal of pulp wastewater. The K values (apparent first-order rate constant values) showed that the COD removal rate followed the pseudo-first-order kinetic model. This study also indicated that the main constituent FeO presence in iron slag reaction with O3 in heterogeneous catalytic ozonation system enhances removal efficiency of color and COD of pulp wastewater.

Application of response surface methodology (RSM) to optimize coagulation–flocculation treatment of leachate using poly-aluminum chloride (PAC) and alum

This work is an effort to remediate rice grain-based biodigester effluent (BDE) by applying the sono-electrocoagulation (SEC) process using Iron as a sacrificial electrode to accomplish this process. A batch reactor is used for the investigation. The effect of the SEC process on the reduction of chemical oxygen demand (COD) and color from the wastewater was studied by varying operating parameters including ultrasonic power (U), current density (j), initial pH (pHi), and electrolysis time (t) in the ranges of 20-60 W, 49.5-247.5 A/m2, 2-10 and 12-60 minutes respectively. The results obtained were optimized by using central composite design (CCD) which is a special feature of the response surface method (RSM). This tool is well applicable in the SEC process to explores the relationships between different varying operating parameters with two responses namely COD and color removal efficiency. The RSM is to use a sequence of designed experiments to obtain an optimal response. The analysis demonstrated that the quadratic regression model fitted well with SEC-generated data. Moreover, no significant difference was found between experimental and predicted data. The coefficient of determination (R2) of 0.9995 and 0.9895 were observed for COD and color removal efficiency. Results indicated that the COD removal efficiency of 93% and color removal efficiency of 88% were found at optimum conditions U of 50, J of 198 A/m2, pHi of 7, and t of 48 minutes.

Biological treatment, ozonation and chemical precipitation were studied at bench scale to investigate color and COD removal efficiencies in three dye waste effluents of cotton, synthetic and woven fabric processing. The aerobic biodegradability of ozonated and unozonated samples was investigated in fill-and-draw activated sludge systems. An ozone dosage of 0.8 g/L was applied for 30 minutes in a semi-batch reactor widi volume of 10 L. Alum, FeCl3 and FeSO4 were studied as coagulants during chemical clarification and anionic polyelectrolyte was used to improve COD removal efficiency. The results indicated that color removal efficiencies of 78 - 100 percent were obtained with ozonation at a dosage of 0.8 g/L. COD removal efficiencies of 59 - 71 percent were obtained with combined treatment of ozonation and chemical clarification, while 62 - 82 percent were achieved with a combination of ozonation and biological treatment. A combination of ozonation and biological treatment is proposed for medium strength wastewater to obtain sufficient color and COD removal. For high strength wastewaters, chemical clarification should be used as a pretreatment before the ozonation and biological treatment to be able to achieve the discharge standards.

A fair amount of India’s gross domestic product is contributed by distilleries, which are considered the backbone industries of India. Distilleries indeed play key roles in India’s exports. Distillery wastewater is recognized as one of the recalcitrant wastewaters, containing extremely high organic loading and having an adverse impact when released into the environment. The aim of the present study was to optimize the conditions required for attaining improved COD removal efficiency in distillery wastewater through an electro-Fenton (EF) process. The effect of various operating parameters, viz. H2O2 dosage (555–2220 mg L−1), spacing between the iron electrodes (2–6 cm), electrode dipping area (35–65 cm2), initial pH (2–9), and constant voltage supply (5–15 V), were investigated by carrying out the EF process in batch mode. As a result of the EF study, COD removal efficiency of 79.5% for an initial COD of 5500–6000 mg L−1 was achieved for the distillery wastewater under the condition of 1665 mg L−1 H2O2, 2.5 cm of spacing between the electrodes, 55 cm2 of electrode dipping area, pH 3, and constant voltage supply of 5 V. In the same study, the kinetics of the process was also investigated, and it obeyed the pseudo-first-order reaction. The EF process effectively degrades complex organic compounds in distillery wastewater into simpler, potentially less toxic substances, as demonstrated by gas chromatography–mass spectrometry (GC-MS) analysis and pathway elucidation. The central composite design (CCD) of the response surface methodology (RSM) model was used to optimize the COD removal in distillery wastewater through the EF process. In line with the batch experimental results, RSM projections also indicated that the optimum conditions required for attaining a maximum of 70.8% COD removal efficiency in distillery wastewater are found to be 1402 mg L−1 H2O2 dosage, 3 cm electrode spacing, 60 cm2 dipping area, 5 V voltage, and pH 2.18. The research data supported the conclusion that the EF process is feasible for distillery wastewater treatment, which preferably can be applied extensively.

Optimization of batch process parameters for Congo red color removal by Neurospora crassa live fungal biomass with wheat bran dual adsorbent using response surface methodology

Empirical modeling of olive oil mill wastewater treatment using loofa-immobilized Phanerochaete chrysosporium

This paper presents data for the synthesis and characterization of layer double hydroxides (LDH) and their use for color and chemical oxygen demand (COD) removal from effluents generated by a textile industry. Adsorption studies with raw and biologically treated (activated sludge) textile effluent showed that the pseudo-second order model best fitted the experimental data, leading to adsorption coefficients of 39.1 and 102.9 mgCOD/gLDH for raw and treated effluents, respectively. The best conditions for color and COD removal were obtained at lower values of temperature and pH (25 °C and pH 7) and, in these conditions, an LDH dose of 10 g/L resulted in color removal efficiencies of 56% for samples of raw and 66% for samples of treated effluent. Recycling studies indicated that the reuse of thermally treated LDH led to a progressive loss in the removal efficiencies of COD and color. The reduction was more pronounced with samples of the raw textile effluent. LDH characterization performed before and after each adsorption and regeneration experiment showed that there was no intercalation of dye molecules in the interlayer region of the LDH, indicating that COD and color removal might be due to the adsorption of organic molecules onto the LDH surface.

Diatoms hold great promise as potential sources of biofuel production. In the present study, the biomass and lipid production in the marine diatom Navicula phyllepta, isolated from Cochin estuary, India and identified as a potential biodiesel feedstock, were optimized using Plackett-Burman (PB) statistical experimental design followed by central composite design (CCD) and response surface methodology (RSM). The growth analyses of the isolate in different nitrogen sources, salinities and five different enriched sea water media showed the best growth in the cheapest medium with minimum components using urea as nitrogen source at salinity between 25 and 40gkg-1. Plackett-Burman experimental analyses for screening urea, sodium metasilicate, sodium dihydrogen phosphate, ferric chloride, salinity, temperature, pH and agitation influencing lipid and biomass production showed that silicate and temperature had a positive coefficient on biomass production, and temperature had a significant positive coefficient, while urea and phosphate showed a negative coefficient on lipid content. A 24 factorial central composite design (FCCD) was used to optimize the concentration of the factors selected. The optimized media resulted in 1.62-fold increase (64%) in biomass (1.2±0.08gL-1) and 1.2-fold increase (22%) in estimated total lipid production (0.11±0.003gL-1) compared to original media within 12days of culturing. A significantly higher biomass and lipid production in the optimized medium demands further development of a two-stage strategy of biomass production followed by induction of high lipid production under nutrient limitation or varying culture conditions for large-scale production of biodiesel from the marine diatom.

The effects of chromium bioaccumulation in Pseudokirchneriella subcapitata were evaluated by Central Composite Design (CCD), factorial 2 2 and Response Surface Methodology (RSM). All the models of regression generated by CCD were highly significant, with R 2 between 77 and 88%, which is the percentual variability in the response that the model can account for. This is indicative of a satisfactory representation of the process models whose data can be used for simulations of response. The maximum shrinkage biovolume presented 28–69% reduction compared to controls. Results from this study suggest that the smaller algal cells amplify metal binding sites, leading to an increased bioaccumulation and a consequential increased capacity to accumulate chromium. Nevertheless, the absorption capacity decreases for more elevated chromium concentrations and for longer exposure. Keywords : Algae, Biovolume, Central Composite Design, Metal, Selenastrum capricornutum .

Optimization using response surface methodology and kinetic study of Fischer–Tropsch synthesis using SiO2 supported bimetallic Co–Ni catalyst