Optimization of low-grade coal and refuse-derived fuel blends for improved co-combustion behavior in coal-fired power plants.

This study is aimed at utilizing three waste materials, i.e., solid refuse fuel (SRF), tire derived fuel (TDF), and sludge derived fuel (SDF), as eco-friendly alternatives to coal-only combustion in co-firing power plants.

Identifying the socioeconomic determinants of industrial hazardous waste generation: South Korea as a case study.

The South Korean government has set an ambitious target to reduce industrial hazardous waste (IHW) as part of its transition towards a circular economy. Moreover, effective management of IHW within the country has become crucial, given that IHW trade is regulated by the Basel Convention. Despite the urgent need for well-founded environmental policies, there is a lack of essential information on the characteristics and determinants of IHW generation, which hinders the effectiveness of existing IHW policies.

Optimization of tetracycline removal from water by iron-coated pine-bark biochar.

We synthesized iron-coated pine-bark biochar (Fe-PBB) and determined the optimal conditions for removing the antibiotic tetracycline from water. The Fe-PBB was synthesized by depositing iron oxide on pyrolyzed pine-bark waste via a facile co-precipitation method. Characterization (SEM, EDX, and TGA) showed successful deposition of a mass of approximately 27% (w/w) iron on the PBB to synthesize Fe-PBB.

Production and characterization of cost-effective magnetic pine bark biochar and its application to remove tetracycline from water.

Low-cost adsorbent, pine bark biochar (PBB) from the forest residue, was produced and applied to remove tetracycline (TC) from aqueous solution via adsorption pathway. The PBB, hence obtained, was modified using aqueous ferric and ferrous ion solutions to obtain magnetic pine bark biochar (M-PBB). Batch adsorption experiments were conducted to examine the adsorption of TC by PBB and M-PBB in the variation of pH, contact time, dosage, and temperature.

High-Resolution Environmentally Extended Input-Output Model to Assess the Greenhouse Gas Impact of Electronics in South Korea.

South Korea is a global leader in electronics, but little is known about their climate change impact. Here, we estimate the direct and indirect greenhouse gas (GHG) emissions of Korean electronics by developing a new and high-resolution (∼380 sectors) environmentally extended input-output model, named KREEIO. We find that final demand for Korean electronics led to nearly 8% of national GHG emissions in 2017, mostly because of indirect emissions embodied in the electronics supply chain.

Characteristics of industrial hazardous waste generation in South Korea from 2008 to 2018 based on decoupling and decomposition analysis.

The industrial hazardous waste (IHW) generation to meet consumption is steadily increasing, resulting in environmental, health, and social problems around the world. To address IHW at the source, it is critical to understand the generation characteristics and key drivers on industrial hazardous waste generation (IHWG). This study analysed the generation characteristics of IHW of South Korea from 2008 to 2018 by decoupling and index decomposition analysis using Log Mean Divisia Index (LMDI) model.

Experimental modeling and optimization for the reduction of hexavalent chromium in aqueous solutions using ascorbic acid.

In this study, we investigated the reduction of toxic Cr(VI) to less toxic Cr(III) using ascorbic acid in various aqueous solutions: deionized water, synthetic soft water, synthetic hard water, and real tap water. The experiments were performed using a statistical experimental design. Response surface methodology (RSM) was used to correlate Cr(VI) reduction (response variable) with experimental parameters such as initial Cr(VI) concentration, humic acid concentration, and ascorbic acid dosage.

Decarbonization of Vietnam's economy: decomposing the drivers for a low-carbon growth.

Vietnam has witnessed a rapid increase in national-level CO emissions due to rising urbanization, economic expansion, export growth, and industrial development. Moreover, to support the ambitious economic growth targets, reliance on and consumption of fossil fuels are increasing by each passing year. With this circumstance, this study aims to analyze the key drivers of CO emissions in Vietnam from 1990 to 2016 using the Kaya identity and decomposition method.

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 (CaCO) and sodium chloride (NaCl) concentrations were optimized to enhance methane production while minimizing operating cost.

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 (20-40wt%), 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.

Ethanol mediated As(III) adsorption onto Zn-loaded pinecone biochar: Experimental investigation, modeling, and optimization using hybrid artificial neural network-genetic algorithm approach.

Organic matters (OMs) and their oxidization products often influence the fate and transport of heavy metals in the subsurface aqueous systems through interaction with the mineral surfaces. This study investigates the ethanol (EtOH)-mediated As(III) adsorption onto Zn-loaded pinecone (PC) biochar through batch experiments conducted under Box-Behnken design. The effect of EtOH on As(III) adsorption mechanism was quantitatively elucidated by fitting the experimental data using artificial neural network and quadratic modeling approaches.

Novel synthesis and applications of Thiomer solidification for heavy metals immobilization in hazardous ASR/ISW thermal residue.

The present paper reports the novel synthesis and application of Thiomer solidification for heavy metal immobilization in hazardous automobile shredder residues and industrial solid waste (ASR/ISW) thermal residues. The word Thiomer is a combination of the prefix of a sulfur-containing compound "Thio" and the suffix of "Polymer" meaning a large molecule compound of many repeated subunits. To immobilize heavy metals, either ASR/ISW thermal residues (including bottom and fly ash) was mixed well with Thiomer and heated at 140°C.

Characterization of co-digestion of industrial sludges for biogas production by artificial neural network and statistical regression models.

The characteristics and impact of industrial sludges of paper, chemical, petrochemical, automobile, and food industries situated in the Ulsan Industrial Complex, Ulsan, Republic of Korea in co-digestion for biogas production were assessed by artificial neural network (ANN) and statistical regression models. The regression model was based on a simplex-centroid mixture design and the ANN was based on a resilient back-propagation algorithm (topology 5-7-1). Using connection weights and bias of the trained ANN model, the impact of each sludge of co-digestion was assessed using Garsons' algorithm.

Back propagation neural network model for predicting the performance of immobilized cell biofilters handling gas-phase hydrogen sulphide and ammonia.

Lab scale studies were conducted to evaluate the performance of two simultaneously operated immobilized cell biofilters (ICBs) for removing hydrogen sulphide (H2S) and ammonia (NH3) from gas phase. The removal efficiencies (REs) of the biofilter treating H2S varied from 50 to 100% at inlet loading rates (ILRs) varying up to 13 g H2S/m(3) ·h, while the NH3 biofilter showed REs ranging from 60 to 100% at ILRs varying between 0.5 and 5.

Optimization of co-digestion of various industrial sludges for biogas production and sludge treatment: methane production potential experiments and modeling.

Optimal biogas production and sludge treatment were studied by co-digestion experiments and modeling using five different wastewater sludges generated from paper, chemical, petrochemical, automobile, and food processing industries situated in Ulsan Industrial Complex, Ulsan, South Korea. The biomethane production potential test was conducted in simplex-centroid mixture design, fitted to regression equation, and some optimal co-digestion scenarios were given by combined desirability function based multi-objective optimization technique for both methane yield and the quantity of sludge digested. The co-digestion model incorporating main and interaction effects among sludges were utilized to predict the maximum possible methane yield.

Occurrence and removal of antibiotics, hormones and several other pharmaceuticals in wastewater treatment plants of the largest industrial city of Korea.

Occurrence and removal efficiencies of 20 pharmaceuticals and personal care products (PPCPs) including antibiotics, hormones, and several other miscellaneous pharmaceuticals (analgesics, antiepileptics, antilipidemics, antihypertensives, antiseptics, and stimulants) were investigated in five wastewater treatment plants (WWTPs) of Ulsan, the largest industrial city of Korea. The compounds were extracted from wastewater samples by solid-phase extraction (SPE) and analyzed by High-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The results showed that acetaminophen, atenolol and lincomycin were the main individual pollutants usually found in concentrations over 10 μg/L in the sewage influent.

Enhanced methane recovery by food waste leachate injection into a landfill in Korea.

The current food waste leachate (FWL) disposal practice in Korea warrants urgent attention and necessary action to develop an innovative and sustainable disposal strategy, which is both environmentally friendly and economically beneficial. In this study, methane production by FWL injection into a municipal solid waste landfill with landfill gas (LFG) recovery facility was evaluated for a period of more than 4 months. With the target of recovering LFG with methane content ~50%, optimum LFG extraction rate was decided by a trial and error approach during the field investigation in five different phases.

Sorption of triclosan onto activated carbon, kaolinite and montmorillonite: effects of pH, ionic strength, and humic acid.

Sorption of triclosan on three sorbents, viz., activated carbon, kaolinite and montmorillonite was studied as a function of pH, ionic strength and humic acid (HA) concentration through controlled batch experiments. Triclosan sorption was found to be higher in the acidic pH range, as varying pH showed significant influence on the surface charge of the sorbents and degree of ionization of the sorbate.

Methane production from food waste leachate in laboratory-scale simulated landfill.

Due to the prohibition of food waste landfilling in Korea from 2005 and the subsequent ban on the marine disposal of organic sludge, including leachate generated from food waste recycling facilities from 2012, it is urgent to develop an innovative and sustainable disposal strategy that is eco-friendly, yet economically beneficial. In this study, methane production from food waste leachate (FWL) in landfill sites with landfill gas recovery facilities was evaluated in simulated landfill reactors (lysimeters) for a period of 90 d with four different inoculum-substrate ratios (ISRs) on volatile solid (VS) basis. Simultaneous biochemical methane potential batch experiments were also conducted at the same ISRs for 30 d to compare CH(4) yield obtained from lysimeter studies.

Urban water infrastructure optimization to reduce environmental impacts and costs.

Urban water planning and policy have been focusing on environmentally benign and economically viable water management. The objective of this study is to develop a mathematical model to integrate and optimize urban water infrastructures for supply-side planning and policy: freshwater resources and treated wastewater are allocated to various water demand categories in order to reduce contaminants in the influents supplied for drinking water, and to reduce consumption of the water resources imported from the regions beyond a city boundary. A case study is performed to validate the proposed model.

Oxidation of polyvinyl alcohol by persulfate activated with heat, Fe2+, and zero-valent iron.

The oxidation of polyvinyl alcohol (PVA) by persulfate (S(2)O(8)(2-)) activated with heat, Fe(2+), and zero-valent iron (Fe(0)) was investigated via batch experiments. It was hypothesized that elevated temperature and the addition of Fe(2+) or Fe(0) into a persulfate-water system could enhance the oxidation of PVA by activated persulfate. Increasing the temperature from 20 to 60 degrees C or 80 degrees C accelerated the oxidation rate of PVA, which achieved complete oxidation in 30 and 10 min, respectively.

A unified model of ammonium oxidation rate at various initial ammonium strength and active ammonium oxidizer concentrations.

This paper attempts to provide insight into the biological ammonium oxidation process applied to high-strength ammonium wastewater treatment. The ammonium oxidation process has been investigated at various ammonium and biomass concentrations. Using the oxygen uptake rate (OUR) method, a proportion of both active ammonium oxidizers (AAO) and nitrite oxidizers to the total suspended solids were separately estimated, and then tested to normalize the ammonium oxidation rate at various ammonium strengths and AAO concentrations.

Methane production potential of leachate generated from Korean food waste recycling facilities: a lab-scale study.

This paper examines the applicability of food waste leachate (FWL) in bioreactor landfills or anaerobic digesters to produce methane as a sustainable solution to the persisting leachate management problem in Korea. Taking into account the climatic conditions in Korea and FWL characteristics, the effect of key parameters, viz., temperature, alkalinity and salinity on methane yield was investigated.

Adsorption equilibrium and kinetics of polyvinyl alcohol from aqueous solution on powdered activated carbon.

In this study, powdered activated carbon (PAC) was used to remove polyvinyl alcohol (PVA) from the aqueous PVA solution. The adsorption kinetics has been studied pertaining to various initial PVA concentration and PAC dosage. The rates of adsorption were found to conform to the second-order kinetics with good correlation.

An analysis of synergistic and antagonistic behavior during BTEX removal in batch system using response surface methodology.

The removal of benzene, toluene, ethylbenzene and xylene (BTEX) as quaternary mixtures were studied in batch systems using a well-defined mixed microbial culture. The synergistic and antagonistic effects of total BTEX removal (BTEXT-RE) due to the presence of mixed substrate was evaluated through experiments designed by response surface methodology (RSM). The low and high concentrations of individual BTEX were 15 and 75 mg l(-1), respectively.