Sediment quality assessment guidelines(SQAGs) for seven trace elements were suggested to build an assessment system of freshwater sediment quality for a regulatory program in Korea. In this study, current one-step SQAGs were divided into three levels based on the probability of toxicity occurrence, namely, the threshold-effect-level(TEL), the probable-effect-level(PEL), and the apparent-effect-threshold(AET). A sediment toxicity database consisting of field-collected sediments and toxicity results from three different species were used to derive TEL, PEL, and AET. The ambient background concentrations of trace elements in freshwater sediments were used instead of the TEL values because TEL values were lower than the ambient background levels. To validate the reliability of the new SQAGs, a separate sediment toxicity database based on G. sobaegensis was used. When the mean quotient value for the PEL was 0.34, the reliability reached a maximum of 87% with a positive predictive value of 94% and a negative predictive value of 85%. These results showed the newly derived SQAGs were very useful for assessing and predicting the toxicity of field sediments in Korea. Finally, ambient background concentrations, a mean quotient of PEL of 0.34, and AETs were used to classify the quality of the field-collected sediments into four categories.

Biogas is a mixture of mainly CH4 and CO2, which can be generated from anaerobic digestion of organic materials. The use of biogas is mostly limited to thermal energy and electricity generation. However, the abundance of cheap shale gas and solar energy could drive out biogas for such applications in the near future. Hence, alternative applications of biogas have recently received great attention among researchers across the globe. This review, for the first time, discusses the feasibility of the bioconversion of biogas to value-added products, including single cell protein as animal feed supplement, and methanol that is an important building block in the chemical industries. Mechanisms of the process, microorgnisms involved and key parameters affecting their efficiency are discussed in detail. Some future research needs are suggested in order to deepen our understanding of these biochemical processes.

The microbial communities and operational performances of a conventional anaerobic digester (AD) and an AD combined with microbial electrolysis cells (ADMEC) were investigated. Primary sludge and waste-activated sludge were used as substrates, and next-generation sequencing (NGS) techniques were used to analyze the microbial characteristics. The results show that ADMEC can achieve a faster stabilization rate, higher organic decomposition, and methane production performance than AD. After both the ADMEC and AD reached a steady state, microbial results revealed that Methanobacterium beijingense and Methanosaeta concilii were the dominant methane-generating archaeal species in AD. In ADMEC, the relative abundance of methylotrophic methanogens (Thermoplasmata class), which has higher methane productivity than other methanogens, is significantly improved. For bacterial communities, an improved relative abundance of the Cloacamonas phylum, which is involved in amino acid fermentation, and in the Erysipelotrichi class, which grows well in environments with high organic concentrations, was observed in ADMEC. In summary, ADMEC is more efficient than AD because organic degradation and methanol production accelerated by bioelectrochemical reactions occur in ADMEC, leading to a favorable environment for the growth of methylotrophic methanogens in bulk solution.

The lignocellulosic derived cornstalk was sulfonated (SCS) to prepare an adsorbent, and cationic dye methylene blue (MB) was adsorbed using SCS to evaluate its usability. Sulfonation improved the number of carboxyl groups (-COOH) and increased the porosity and surface area of carbon. In the adsorption process in which MB is adsorbed using SCS in aqueous solution, the sulfone group expanded the form of the sulfonated adsorbent to increase the exposure of anions (sulfonic-acid (R-SO3H), carboxylic groups, and bonded OH-group) to the surface. As a result, the adsorption efficiency of MB, a cationic dye for SCS, was improved. The results of kinetics, adsorption isotherm and thermodynamics were suitable for Pseudo-2nd-order and Langmuir, and the adsorption process was endothermic and spontaneous physical adsorption. The maximal adsorptions capacity with Langmuir model was found to be 504.3 mg/g at 293K. Sulfonation improved not only electrostatic interaction but also π-π stacking in the adsorption process, which was very advantageous in adsorbing cationic dyes using lignocellulose-based adsorbents.

Insects have a great potential to be used as feedstocks for biodiesel production due to their intrinsic high lipid contents. In particular, biodiesel production from black soldier fly larvae (BSFL) is promising because of its advantages in engineering aspects such as a rapid proliferation, more lipid storage due to long-development time in larva stage, self-separation from organic waste. In this study, biodiesel was synthesized through (trans)esterification of BSFL grown on food waste to achieve both biofuel production from organic waste materials. In addition, all fuel properties of the biodiesel were examined to evaluate its feasibility as a potential transportation fuel in Korea. The highest yield of biodiesel obtained in this study was 86.51%. All the parameters of biodiesel produced from BSFL satisfied the Korea fuel standard (KS M 2965) except oxidation stability. The quality criterion of oxidation stability met the fuel standard with an addition of small quantity of <i>tert</i>-butylhydroquinone.

Nowadays, air pollution and consequently global warming are the major problems that the earth is faced with. These issues can influence climate change and human health. Building façades can play a significant role in the air quality of the urban environment. Therefore, this study draws upon the ability of nature in controlling carbon dioxide to compare three types of bio-façades (i.e. Water façade, Green façade, and Microalgae façade) and to identify an appropriate one. For this purpose, we analyzed documents and scientific literature qualitatively. Then, we identified the aforementioned types of biological façades and selected the most optimal one through the comparison. Additionally, for this comparison, the analytical hierarchy process (AHP) method was employed that resulted in achieving the higher scores by the microalgae façade among other bio-façades mentioned above. The major criteria considered for the AHP analysis included climatic, economic, architectural, environmental, and structural aspects of using the noted bio-façades in buildings. It should be emphasized that the environmental aspect was obtained as the most influential criterion among others. Finally, some technical tips and design requirements for bioreactors are depicted and discussed along with their upcoming challenges and future research direction.

To explore cheap, easily available and high adsorption performance bioadsorbent is still an important task for azo dye pollution control. In this study, the Methyl orange (MO) adsorption capacity by a novel bioadsorbent obtained from lychee and longan pericarps via simple modification was investigated. Prepared pericarps were modified by PEI at 30˚C and 65˚C, which improved the adsorption performance confirmed by batch adsorption experiments. The characteration of modified pericarps by X-ray diffraction, scanning electron microscopy and zeta potential indicated that the enhanced adsorption performance may be due to the abundant amines and imines and stronger electropositivity. The maximum adsorption capacity (349.37 mg/g) was observed for LC@PEI-65 at 45˚C and pH 4. Freundlich isotherm model fitted pretty well with the isotherm experiment data, and the isotherm experimental data were preferably described by pseudo-second order model indicating the chemical adsorption process, and the intra-particle diffusion also involved in the adsorption process. Characterization and adsorption tests suggested electrostatic interaction played a key role in MO removal, accompanied by intermolecular hydrogen bond, π-π dispersion interaction and pore filling collectively. The present study show that the cost-effective PEI modified pericarps could possess a hopeful application for azo dye removal from wastewater.

As part of the implementation of a rainwater harvesting system as an alternative water source supply for non-potable use, therefore the characteristic of chemical compounds was significantly explored. The Department of Chemistry, Malaysia, gave the data set for three years (2017-2019). Some chemometric techniques, including PCA, were performed to identify the dimensionality of the rainwater data, hence establishing the rainfall index's purity to determine the quality of rainwater in the study area. Discriminant analysis managed to differentiate each rain gauge station. Cluster analysis was then applied to perform smaller group of rain gauge stations. The result demonstrates that sea salt, secondary aerosols, trace metals, crustal origin, and organic acid dominated the dimensionality of rainwater data with a total variance of 53.38% and indicated that the PRI was significantly diversified into good purity of rainfall index (GPRI), (Labuan and Danum Valley), moderate purity of rainfall index (MPRI), (Kuching and Tawau) and bad purity of rainfall index (BPRI), (Kota Kinabalu and Bintulu). From the study, it can be stipulated that the chemical composition of rainwater in the study area was attributable to the local activities.

The present research introduces adsorption of sulfonated cobalt phthalocyanine catalyst (Europhtal) from the real wastewater that is produced in the mercaptan removal unit (Merox) of the third refinery, South Pars Gas Complex (SPGC), Assaluyeh, Iran. Therefore, novel low-cost natural zeolite modified with polyaluminium chloride (PAC) was investigated as an adsorbent for the treatment of Europhtal wastewater. Central composite design (CCD), as a set of response surface methodology (RSM), was applied to acquire optimum operational conditions such as contact time, pH, adsorbent dosage, and Europhtal concentration. Results showed that the removal percentage of Europhtal in the real wastewater was 93.4% at best operating condition consisting of a pH of 6.7, sonication time of 8 min, 0.035 g of adsorbent. The obtained results were evaluated by adsorption isotherms and kinetic parameters. It was found that the equilibrium data matched the Freundlich model acceptably, with the maximum experimental adsorption capacity of this model was 687.51 mg g-1 at 301.15 K. From the kinetic data, it was revealed that the adsorption process followed the pseudo-second-order kinetic model. Furthermore, the obtained thermodynamic parameters such as ∆H°, ∆S°, and ∆G° imply the endothermic essence of adsorption proceeding spontaneously.

In this study, it was aimed to determine the heavy metal pollution and the factors causing this pollution in the water and sediment of the Bartın River during rainy and dry periods. Concentrations of Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn, As and some other metals in water and sediment samples collected from 4 different points during rainy and dry periods were investigated. It has been determined that both natural sources (soil erosion) and anthropogenic sources (runoff in urban and agricultural areas) affect metal concentrations in water and sediment during the rainy period. Heavy metal accumulation was less at the point with the least water depth (≈ 2 m). Higher concentrations were determined at the point where soil transport was highest during the rainy period. Since EF values of As, Pb, Zn and Li were greater than two in both periods, it was determined that they were affected by anthropogenic sources (wastewater discharges, agricultural and urban activities). EF values less than one showed that Co, Cr, Ba, Ni, Mn were related to lithogenic actions and riverbank runoff. Non-carcinogenic effects caused by metals did not pose a risk to adults and children.