Fuzzy multi-objective optimization case study based on an anaerobic co-digestion process of food waste leachate and piggery wastewater

This paper presents the development and evaluation of fuzzy multi-objective optimization for decision-making that includes the process optimization of anaerobic digestion (AD) process. The operating cost criteria which is a fundamental research gap in previous AD analysis was integrated for the case study in this research. In this study, the mixing ratio of food waste leachate (FWL) and piggery wastewater (PWW), calcium carbonate (CaCO3) and sodium chloride (NaCl) concentrations were optimized to enhance methane production while minimizing operating cost. The results indicated a maximum of 63.3% satisfaction for both methane production and operating cost under the following optimal conditions: mixing ratio (FWL: PWW) – 1.4, CaCO3 – 2970.5 mg/L and NaCl – 2.7 g/L. In multi-objective optimization, the specific methane yield (SMY) was 239.0 mL CH4/g VSadded, while 41.2% volatile solids reduction (VSR) was obtained at an operating cost of 56.9 US$/ton. In comparison with the previous optimization study that utilized the response surface methodology, the SMY, VSR and operating cost of the AD process were 310 mL/g, 54$/ton, respectively. The results from multi-objective fuzzy optimization proves to show the potential application of this technique for practical decision-making in the process optimization of AD process. © 2018 Elsevier Lt

Streamlining extracellular polymeric substance removal: Fuzzy multi-objective optimization of ultrasonic-Fenton treatment

Managing high water content sludge in wastewater treatment is crucial for sustainability. This involves a complex challenge of maximizing the removal of loosely bound extracellular polymeric substances (LB-EPS) while minimizing ultrasonic-Fenton process costs. This study introduces a novel approach to address these conflicting objectives by adopting fuzzy multi-objective optimization. This method reconciles the conflicting objectives by identifying the optimal conditions for ferrous ion (Fe2+) dosage, hydrogen peroxide (H2O2) dosage, and ultrasonication time. The optimization model incorporates empirical equations that define the effects of Fenton’s reagent and ultrasonication on LB-EPS removal, as well as considerations for material and electricity usage costs and the cumulative uncertainties associated with experimental runs. To effectively capture the trade-offs between EPS removal and process costs, the ɛ -constraint method was utilized to delineate the Pareto front. This approach significantly enhances LB-EPS removal from anaerobically digested sludge and establishes boundary limits within the Pareto front for practical application within the context of fuzzy optimization. The optimized solution derived from this innovative approach resulted in the conditions of 10 mM Fe2+dosage, 100 mM H2O2 dosage, and 10 min of ultrasonication. This configuration achieves an impressive 60.7% ± 3.7% LB-EPS removal while maintaining a cost of 26.6 USD/L and ensuring 100% overall satisfaction. This research represents a significant advancement in sludge dewatering strategies. It underscores the pivotal role of innovative decision-making approaches in advancing the field of sludge dewatering methodologies for more sustainable wastewater treatment practices

Solidification/stabilization of ASR fly ash using thiomer material: Optimization of compressive strength and heavy metals leaching

Optimization studies of a novel and eco-friendly construction material, Thiomer, was investigated in the solidification/stabilization of automobile shredded residue (ASR) fly ash. A D-optimal mixture design was used to evaluate and optimize maximum compressive strength and heavy metals leaching by varying Thiomer (20–40 wt%), ASR fly ash (30–50 wt%) and sand (20–40 wt%). The analysis of variance was utilized to determine the level of significance of each process parameters and interactions. The microstructure of the solidified materials was taken from a field emission-scanning electron microscopy and energy dispersive X-ray spectroscopy that confirmed successful Thiomer solidified ASR fly ash due to reduced pores and gaps in comparison with an untreated ASR fly ash. The X-ray diffraction detected the enclosed materials on the ASR fly ash primarily contained sulfur associated crystalline complexes. Results indicated the optimal conditions of 30 wt% Thiomer, 30 wt% ASR fly ash and 40 wt% sand reached a compressive strength of 54.9 MPa. For the optimum results in heavy metals leaching, 0.0078 mg/L Pb, 0.0260 mg/L Cr, 0.0007 mg/L Cd, 0.0020 mg/L Cu, 0.1027 mg/L Fe, 0.0046 mg/L Ni and 0.0920 mg/L Zn were leached out, being environmentally safe due to being substantially lower than the Korean standard leaching requirements. The results also showed that Thiomer has superiority over the commonly used Portland cement as a binding material which confirmed its potential usage as an innovative approach to simultaneously synthesize durable concrete and satisfactorily pass strict environmental regulations by heavy metals leaching. © 2017 Elsevier Lt

Fuzzy Optimization on the Synthesis of Chitosan-Graft-Polyacrylic Acid with Montmorillonite as Filler Material: A Case Study

In this paper, the synthesis of a chitosan–montmorillonite nanocomposite material grafted with acrylic acid is presented based on its function in a case study analysis. Fuzzy optimization is used for a multi-criteria decision analysis to determine the best desirable swelling capacity (YQ) of the material synthesis at its lowest possible variable cost. For YQ, the integrating the result’s cumulative uncertainty is an essential element to investigate the feasibility of the developed model equation. The Pareto set analysis is able to set the appropriate boundary limits for YQ and the variable cost. Two case studies are presented in determining the lowest possible cost: Case 1 for maximum YQ, and Case 2 for minimum YQ. These boundary limits were used in the fuzzy optimization to determine its global optimum results that achieved the overall satisfaction ratings of 67.2% (Case 1) and 52.3% (Case 2). The synthesis of the polyacrylic acid/chitosan material for Case 1 resulted in 305 g/g YQ and 10.8 USD/kg, while Case 2 resulted in 97 g/g YQ and 12.3 USD/kg. Thus, the fuzzy optimization approach proves to be a practical method for examining the best possible compromise solution based on the desired function to adequately synthesize a material

Production of Chemically Modified Bio-Based Wood Adhesive from <i>Camote</i> and Cassava Peels

Adhesives are significant for manufacturing competent, light, and sturdy goods in various industries. Adhesives are an important part of the modern manufacturing landscape because of their versatility, cost-effectiveness, and ability to enhance product performance. Formaldehyde and polymeric diphenylmethane diisocyanate (PMDI) are conventional adhesives utilized in wood applications and have been classified as carcinogenic, toxic, and unsustainable. Given the adverse environmental and health effects associated with synthetic adhesives, there is a growing research interest aimed at developing environmentally friendly bio-based wood adhesives derived from renewable resources. This study aimed to extract starch from camote and cassava peels and focuses on the oxidization of starch derived from camote and cassava peels using sodium hypochlorite to create bio-based adhesives. The mean yield of starch extracted from camote and cassava peels was 13.19 ± 0.48% and 18.92 ± 0.15%, respectively, while the mean weight of the oxidized starches was 34.80 g and 45.34 g for camote and cassava, respectively. Various starch ratios sourced from camote and cassava peels were examined in the production of bio-based adhesives. The results indicate that the 40:60 camote to cassava ratio yielded the highest solid content, while the 80:20 ratio resulted in the best viscosity. Furthermore, the 40:60 ratio produced the most favorable particle board in terms of mechanical properties, density, thickness, swelling, and water absorption. Consequently, the starch extracted from camote and cassava peels holds promise as a potential source for bio-based adhesives following appropriate chemical modification

Mixing-assisted oxidative desulfurization of model sulfur compounds using polyoxometalate/H2O2 catalytic system

Taiwan Desulfurization of fossil fuel derived oil is needed in order to comply with environmental regulations. Dibenzothiophene and benzothiophene are among the predominant sulfur compound present in raw diesel oil. In this study, mixing-assisted oxidative desulfurization of dibenzothiophene and benzothiophene were carried out using polyoxometalate/H2O2 systems and a phase transfer agent. The effects of reaction time (2–30 min) and temperature (30–70 °C) were examined in the oxidation of model sulfur compounds mixed in toluene. A pseudo first-order reaction kinetic model and the Arrhenius equation were utilized in order to evaluate the kinetic rate constant and activation energy of each catalyst tested in the desulfurization process. Results showed the order of catalytic activity and activation energy of the different polyoxometalate catalysts to be H3PW12O40 \u3e H3PM12O40 \u3e H4SiW12O40 for both dibenzothiophene and benzothiophene. © 2016 Chinese Institute of Environmental Engineering

Adsorption of benzothiophene sulfone over clay mineral adsorbents in the frame of oxidative desulfurization

The adsorption of benzothiophene sulfone (BTO) from model fuel oil was investigated using three different clay mineral adsorbents. The adsorption characteristics of clay mineral adsorbents such as activated clay, bentonite and kaolinite were evaluated using Fourier transform infrared spectroscopy and Brunauer, Emmett and Teller surface area analyzer. A batch process was conducted to determine the adsorption performances at varying contact time, reaction temperature and initial concentration. Increasing adsorption capacities followed the order of kaolinite \u3c bentonite \u3c activated clay. The equilibrium isotherms using Langmuir and Freundlich models yielded a good fit (R2 \u3e 0.98) indicating a monolayer and heterogeneous adsorption. A second order reaction kinetic model showed high suitability (R2 \u3e 0.97) based on the experimental data. Results showed that adsorption follows a two-step process: (1) fast adsorption rate for the first two hours and (2) markedly slow adsorption rate until equilibrium. The clay minerals have different functional groups present in its surface which determines the essential adsorption characteristics. The thermodynamic parameters for BTO adsorption onto clay mineral adsorbents indicated an endothermic reaction. Activated clay and kaolinite were spontaneous and non-spontaneous, respectively, while bentonite was found to be only non-spontaneous at 25 °C. In comparison with conventional adsorbents, activated clay was found to be superior in the application of sulfone adsorption in fuel oil. © 201

Fuzzy Optimization for the Remediation of Ammonia: A Case Study Based on Electrochemical Oxidation

This case study covers the application of the fuzzy optimization in simultaneously satisfying various constraints that include the compliance of ammonia and nitrate concentrations with stringent environmental standards. Essential components in the multi-criteria decision-making analysis is in the utilization of the Box-Behnken design (BBD) response equations, cost equations and the cumulative uncertainty of response towards the sodium chloride dosage, current density and electrolysis time parameters. The energy consumption in the electrochemical oxidation of ammonia plays an essential role in influencing the total operating cost analysis. The determination of boundary limits based on the global optimum resulted in the complete ammonia removal and USD 64.0 operating cost as its maximum boundary limits and the 40.6% ammonia removal and USD 17.1 as its minimum boundary limits. Based on the fuzzy optimal results, the overall satisfaction level incurred a decrease in adhering with a lower ammonia standard concentration (10 mg/L at 80.3% vs. 1.9 mg/L at 76.1%) due to a higher energy consumption requirement. Global optimal fuzzy results showed to be highly cost efficient (232.5% lower) as compared to using BBD alone. This demonstrates the practicality of fuzzy optimization applications in the electrochemical reactions

Oxidation by H2O2 of bezothiophene and dibenzothiophene over different polyoxometalate catalysts in the frame of ultrasound and mixing assisted oxidative desulfurization

© 2016 Elsevier Ltd. All rights reserved. Desulfurization involves the removal of refractory sulfur compounds in fossil-fuel derived oils. In this study, an ultrasound and mixing assisted oxidative desulfurization of synthetic oil containing sulfur compounds of benzothiophene and dibenzothiophene were carried out using different polyoxometalate catalysts, H2O2 oxidant and a phase transfer agent. The effects of reaction time (2-30 min) and temperature (30-70 °C) were examined in the oxidation of benzothiophene and dibenzothiophene. Results showed high correlation to the pseudo first-order reaction kinetics (R2 \u3e 0.97) and Arrhenius equation (R2 \u3e 0.99) that draws out the rate constant and activation energy of each catalyst tested in the oxidation process. Oxidation of benzothiophene and dibenzothiophene using different polyoxometalate catalysts showed a catalytic activity trend of Na3PW12O40 \u3e H3PW12O40 \u3e H3PM12O40 \u3e H4SiW12O40. Furthermore, ultrasound and mixing assisted oxidative desulfurization showed comparable results (\u3c5% difference) in oxidation efficiency and better performance in the kinetic reaction rate and activation energy as compared to conventional oxidation step in the oxidative desulfurization technique

Operating cost study through a Pareto-optimal fuzzy analysis using commercial ferrate (VI) in an ultrasound-assisted oxidative desulfurization of model sulfur compounds

There is a need for transportation fuel such as diesel oil to undergo a desulfurization process prior to its usage in order to comply with stringent environmental regulations. Predominant organic sulfur compounds present in fuel oils comprise benzothiophene (BT) and dibenzothiophene (DBT). High sulfur compound reduction is attainable through a desulfurization process but this often leads to risking higher operating cost due to longer reaction time and the use of large amounts of oxidizing agent and phase transfer agent. Fuzzy logic, which is often used in multi-objective decision-making models, is able to meet the desired objective and satisfy the given constraints at the same time. In this study, a pareto-optimal fuzzy analysis is used in order to determine the best conditions in the ultrasound-assisted oxidative desulfurization process and at the same time achieving the lowest possible operating cost for reducing BT and DBT. Process parameters investigated include ultrasonication time (10–30 min), phase transfer agent (100–300 mg), organic to aqueous phase ratio (10:30–30:10), and ferrate concentration (100–300 ppm) for the reduction of model sulfur compounds. Results through fuzzy optimization indicated optimum results of 93.79 % BT conversion with operating cost of US$0.830 and 88.36$ 0.769. © 2015, Springer-Verlag Berlin Heidelberg