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

Choi, Angelo Earvin Sy,Park, Hung Suck Elsevier 2018 Journal of environmental management Vol.223 No.-

<P><B>Abstract</B></P> <P>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 (CaCO<SUB>3</SUB>) 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, CaCO<SUB>3</SUB> – 2970.5 mg/L and NaCl – 2.7 g/L. In multi-objective optimization, the specific methane yield (SMY) was 239.0 mL CH<SUB>4</SUB>/g VS<SUB>added</SUB>, while 41.2% volatile solids reduction (VSR) was obtained at an operating cost of 56.9 US$/ton. In comparison with the previous optimization study that utilized the response surface methodology, the SMY, VSR and operating cost of the AD process were 310 mL/g, 54% and 83.2 US$/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.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Strategically analyzed a case study based on the anaerobic co-digestion process. </LI> <LI> Incorporated operating cost in a multi-objective fuzzy optimization approach. </LI> <LI> Obtained maximum satisfaction of 63.3% for methane production and operating cost. </LI> <LI> Optimal compromise solution obtained an operating cost of 56.9 US$/ton. </LI> <LI> Fuzzy optimum parameters: 1.4 mixing ratio, 2970.5 mg/L CaCO<SUB>3</SUB> and 2.7 g/L NaCl. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ultrasound Assisted Oxidative Desulfurization: A Definitive Screening Design Analysis

Angelo Earvin Sy Choi,Susan Roces,Nathaniel Dugos,Meng-Wei Wan,Hung-Suck Park 한국폐기물자원순환학회 2016 한국폐기물자원순환학회 학술대회 Vol.2016 No.11

The desulfurization of untreated petroleum oil is required in order to comply with stringent environmental regulations. Ultrasound-assisted oxidative desulfurization (UAOD) is an innovative technology for sulfur removal in order to avoid the environmental hazards associated with the combustion of sulfur compounds in raw diesel oil. In this study, diesel oil is treated through UAOD. The effects of ultrasound time (6-30 min), amplitude (20-60%), phase transfer agent (100-500mg), catalyst dosage (10-500mg), H2O2 concentration (30-50%v/v), organic to aqueous phase (OP:AP) ratio (50:50-90:10) and reaction temperature (30-70℃) were examined. The screening analysis used is the definitive screening design that statistically determines the parameters that have a significant effect on the oxidation of diesel oil. Results indicate that significant factors (p-value < 0.5) where ultrasound time, amplitude, catalyst dosage and reaction temperature; while the phase transfer agent, H2O2 concentration and OP:AP ratio were insignificant (p-value > 0.5) on the response of sulfur conversion in the untreated diesel oil. This study concludes that the essential factors to achieve deep desulfurization in diesel oil include ultrasound time, amplitude, H2O2 concentration and reaction temperature which are key factors in the oxidation of sulfur compounds to achieve low sulfur containing diesel oil.

Ultrasound Assisted Oxidative Desulfurization: A Definitive Screening Design Analysis

( Angelo Earvin Sy Choi ),( Susan Roces ),( Nathaniel Dugos ),( Meng-wei Wan ),( Hung-suck Park ) 한국폐기물자원순환학회(구 한국폐기물학회) 2016 한국폐기물자원순환학회 추계학술발표논문집 Vol.2016 No.-

The desulfurization of untreated petroleum oil is required in order to comply with stringent environmental regulations. Ultrasound-assisted oxidative desulfurization (UAOD) is an innovative technology for sulfur removal in order to avoid the environmental hazards associated with the combustion of sulfur compounds in raw diesel oil. In this study, diesel oil is treated through UAOD. The effects of ultrasound time (6-30 min), amplitude (20-60%), phase transfer agent (100-500mg), catalyst dosage (10-500mg), H₂O₂ concentration (30-50%v/v), organic to aqueous phase (OP:AP) ratio (50:50-90:10) and reaction temperature (30-70℃) were examined. The screening analysis used is the definitive screening design that statistically determines the parameters that have a significant effect on the oxidation of diesel oil. Results indicate that significant factors (p-value < 0.5) where ultrasound time, amplitude, catalyst dosage and reaction temperature; while the phase transfer agent, H₂O₂ concentration and OP:AP ratio were insignificant (p-value > 0.5) on the response of sulfur conversion in the untreated diesel oil. This study concludes that the essential factors to achieve deep desulfurization in diesel oil include ultrasound time, amplitude, H₂O₂ concentration and reaction temperature which are key factors in the oxidation of sulfur compounds to achieve low sulfur containing diesel oil.

Fuzzy optimization for the removal of uranium from mine water using batch electrocoagulation: A case study

Choi Angelo Earvin Sy,Futalan Cybelle Concepcion Morales,이정재 한국원자력학회 2020 Nuclear Engineering and Technology Vol.52 No.7

This research presents a case study on the remediation of a radioactive waste (uranium: U) utilizing a multi-objective fuzzy optimization in an electrocoagulation process for the iron-stainless steel and aluminum-stainless steel anode/cathode systems. The incorporation of the cumulative uncertainty of result, operational cost and energy consumption are essential key elements in determining the feasibility of the developed model equations in satisfying specific maximum contaminant level (MCL) required by stringent environmental regulations worldwide. Pareto-optimal solutions showed that the iron system (0 mg/L U: 492 USD/g-U) outperformed the aluminum system (96 mg/L U: 747 USD/g-U) in terms of the retained uranium concentration and energy consumption. Thus, the iron system was further carried out in a multi-objective analysis due to its feasibility in satisfying various uranium standard regulatory limits. Based on the 30 mg/L MCL, the decision-making process via fuzzy logic showed an overall satisfaction of 6.1% at a treatment time and current density of 101.6 min and 59.9 mA/cm2 , respectively. The fuzzy optimal solution reveals the following: uranium concentration e 5 mg/L, cumulative uncertainty e 25 mg/ L, energy consumption e 461.7 kWh/g-U and operational cost based on electricity cost in the United States e 60.0 USD/g-U, South Korea e 55.4 USD/g-U and Finland e 78.5 USD/g-U.

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

Baek, Jin Woong,Choi, Angelo Earvin Sy,Park, Hung Suck Elsevier 2017 Waste management Vol.70 No.-

<P><B>Abstract</B></P> <P>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 (20–40wt%), ASR fly ash (30–50wt%) and sand (20–40wt%). 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 30wt% Thiomer, 30wt% ASR fly ash and 40wt% sand reached a compressive strength of 54.9MPa. For the optimum results in heavy metals leaching, 0.0078mg/LPb, 0.0260mg/L Cr, 0.0007mg/LCd, 0.0020mg/L Cu, 0.1027mg/L Fe, 0.0046mg/L Ni and 0.0920mg/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 asa 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.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Innovative synthesis of Thiomer solidified ASR fly ash. </LI> <LI> D-optimal mixture design of compressive strength and heavy metals leaching. </LI> <LI> Thiomer as a binding material exhibited superiority over ordinary Portland cement. </LI> <LI> Heavy metals were converted to metal sulfides/sulfates upon utilization of Thiomer. </LI> <LI> Thiomer proves to be a novel green construction material. </LI> </UL> </P>

Thiomer solidification of an ASR bottom ash: Optimization based on compressive strength and the characterization of heavy metal leaching

Son, Jae Hyop,Baek, Jin Woong,Choi, Angelo Earvin Sy,Park, Hung Suck ELSEVIER 2017 JOURNAL OF CLEANER PRODUCTION Vol.166 No.-

<P><B>Abstract</B></P> <P>This study examines the function of Thiomer solidification as a novel environment friendly construction material and its immobilization capacity over heavy metals in the automotive shredder residue (ASR) bottom ash. The morphology of the mixture using a field emission-scanning electron microscopy consistently illustrated the effective bonding between Thiomer and sand towards ASR bottom ash due to acting as fillers to reduce the gaps in its surface during Thiomer solidification. A D-optimal mixture design was further utilized in order to evaluate and optimize the parameters of Thiomer (25–35 wt%), ASR bottom ash (30–45 wt%) and sand (30–40 wt%) on the response of compressive strength. Result showed that optimum compressive strength of 55.9 MPa can be attained at 33.6, 36.4 and 30.0 wt% of Thiomer, ASR bottom ash and sand, respectively. The solidified Thiomer specimen showed superior structural strength over ordinary Portland cement concrete at curing time of 1 and 7 days. Furthermore, a mean heavy metal concentrations of 0.055 ppm Cu<SUP>2+</SUP>, 0.105 ppm Zn<SUP>2+</SUP>, 0.045 ppm Pb<SUP>2+</SUP>, 0.078 ppm Cr<SUP>6+</SUP> and 0.002 ppm Cd<SUP>2+</SUP> were achieved at various mixture designs in the heavy metal immobilization which satisfies stringent environmental standards. Thus, the application of Thiomer proves to be a promising construction material that can pose as an alternative over common cement due to promoting high durability and being eco-friendly.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel synthesis of Thiomer solidification in ASR bottom ash. </LI> <LI> Utilized D-optimal mixture design to determine optimum result for compressive strength. </LI> <LI> Thiomer solidification showed superior compressive strength over ordinary cement. </LI> <LI> Results indicate an efficient heavy metals immobilization by Thiomer solidification. </LI> <LI> Thiomer proves to be an innovative eco-friendly construction material. </LI> </UL> </P>

Co-benefit potential of industrial and urban symbiosis using waste heat from industrial park in Ulsan, Korea

Kim, Hyeong-Woo,Dong, Liang,Choi, Angelo Earvin Sy,Fujii, Minoru,Fujita, Tsuyoshi,Park, Hung-Suck Elsevier 2018 Resources, conservation, and recycling Vol.135 No.-

<P><B>Abstract</B></P> <P>Energy depletion and global climate change have stimulated the Korean government to strengthen energy saving and efficiency measures in all sectors. However, in industrial sector where huge energy is consumed, only small portions of the high-grade waste heat from industrial processes have been utilized by another process through industrial symbiosis networks in industrial park and large quantities of low-grade waste heat are mostly discharged into the environment. Through technological assessment of energy balance between waste heat source in industrial park and heat sink in industrial park and urban area, this study systematically develops an industrial-urban symbiosis (I-US) and conducts a co-benefit analysis for 4 scenarios. Based on the investigation on the energy utilization status of Ulsan, the scenarios for potential I-US networks are evaluated. For the supply and demand side, potential energy sources and sinks are estimated at 49,321 and 15,424TJ/yr, respectively, noting that the demand side considered four scenarios based on the local condition analysis. Through these scenarios for the energy symbiosis networks; a reduction of 243,396ton/yr CO<SUB>2</SUB> emission and 48 million US Dollar/yr fuel cost were achieved. Due to a large transition cost for a district heating system, I-US public private partnership business model is highly recommended to attract long-term investment and institutional incentives of carbon credit and energy service companies fund are conducive to put these scenarios into practice.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A comprehensive co-benefit analysis was studied in industrial and urban symbiosis. </LI> <LI> High and low-grade waste heat were focused for the symbiosis networks. </LI> <LI> Four scenarios were investigated for its economic and environmental effects. </LI> <LI> CO<SUB>2</SUB> emissions and fuel cost reduction was achieved in the energy symbiosis network. </LI> </UL> </P>