Kinetics of biological methane oxidation in the presence of non-methane organic compounds in landfill bio-covers

In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH₄) oxidation process were examined. The investigation was performed on compost experiments incubated with CH₄ and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH₄ oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 °C without any NMOCs the V_max value was 35.0 μg ${\text{CH}}_4{\text{h}}^{-1}{\text{g}}_{\text{wet wt}}^{-1}$. This value was reduced to 19.1 μg ${\text{CH}}_4{\text{h}}^{-1}{\text{g}}_{\text{wet wt}}^{-1}$ when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH₄ in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated.     

Fuzzy-based wastewater quality indices for pollution classification: a case study in the United Arab Emirates

This paper presents a fuzzy logic-based tool for assessing the pollution concentration of effluents generated by various industrial and commercial activities. The study proposes a fuzzy overall pollution compliance index (FOPCI) (range 0–100) to classify the wastewater discharged from various types of properties present in Ajman, United Arab Emirates. The work mainly focused on three types of pollution that can occur at the inlets of the wastewater treatment plant of Ajman, due to discharge of industrial and commercial effluents, namely pH pollution, salt pollution, and organic pollution. The proposed FOPCI integrates six characteristics, namely pH, Cl^?, SO₄ ^2?, conductivity, chemical oxygen demand (COD), and fats, oils, and greases (FOG) values into a readily understandable scale. The FOPCI is developed by using the Fuzzy Inference System Toolbox available in MATLAB in two steps, in which during the first step, three sub-indices, namely fuzzy pH compliance index, fuzzy salt compliance index, and fuzzy organic compliance index are developed. It is then processed in the second stage to develop the FOPCI. Fuzzy rules are used to classify effluents quality into six categories based on the concentration of pollutant in the effluent, namely “Excellent Quality”, “Good Quality”, “Acceptable Quality”, “Moderately Polluting”, “Highly Polluting”, and “Extremely Polluting”. This linguistic classification using fuzzy logic will be helpful as a decision support system to provide an outline for the prioritization of plans for wastewater management based on the values of the indices developed.     

A comprehensive systematic review of photocatalytic degradation of pesticides using nano TiO2

Environmental Science and Pollution Research - This study has systematically reviewed all of the research articles about the photocatalytic degradation of pesticides using titanium dioxide (TiO2)...     

Rapid photodegradation and detection of zolpidem over β-SnWO4 and α-SnWO4 nanoparticles: optimization and mechanism

Environmental Science and Pollution Research - We reported the tin (II) tungstate nanoparticles as the photocatalyst and sensor modifier that were synthesized via chemical precipitation reaction...     

A fuzzy multi-attribute approach to select the welding process at high pressure vessel manufacturing

Metal welding process selection calls for extensive know-how which deals with a huge amount of knowledge. Hence, the automation of knowledge through a knowledge-based system will greatly enhance the decision-making process. Fuzzy analytical hierarchy process (AHP)-TOPSIS investigates the relative welding process selection factors and it can compare and evaluate different welding processes between 0 and 1.This paper describes a knowledge-base system developed for identifying the most appropriate welding processes to suit specific circumstances. In the present study, nine important welding processes were used in the system. Ten parameters namely alloy class, material thickness, deposition rate, design application, joint configuration, operator factor, capital cost, equipment portability, filler metal utilization and welding position, are used to determine the best selection among competitive welding processes for high pressure vessel production. Also the sensitivity analysis was carried out for five cases.     

Kinetics and thermodynamics studies of cobalt,strontium and caesium sorption on marble from aqueous solution

Adsorption onto solid phases plays an important role in the transport of radionuclides and contaminants in the environment. Radionuclides in radioactive waste have been considered to be hazardous pollutants, and their migration with groundwater is strongly affected by sorption on the geologic media. Therefore, the knowledge of radionuclide sorption is of great importance in the management of radioactive wastes. A series of batch sorption experiments were conducted separately to investigate sorption and transport behaviour of cobalt, strontium and caesium on and through marble. Batch-mode kinetic and equilibrium studies have been carried out at different temperatures. Sorption experimental data were analysed by kinetic and isotherm models. Based on the results obtained, it can be concluded that the marble is an economic and efficient retaining material for environmental hazardous migration and/or leakage of some radionuclides. Therefore, this study could be used as a starting point to establish and consider that rock as a reactive barrier around the disposal facilities at the nuclear activity centres.     

Spongy Ni/Fe carbonate-fluorapatite catalyst for efficient conversion of cooking oil waste into biodiesel

Environmental Chemistry Letters - Biodiesel produced from animal and plant fat oils is sustainable, but there is a need for efficient heterogeneous catalysts for transesterification of crude oils...     

Effect of leachate recirculation on mesophilic anaerobic digestion of food waste

The effects of using untreated leachate for supplemental water addition and liquid recirculation on anaerobic digestion of food waste was evaluated by combining cyclic water recycle operations with batch mesophilic biochemical methane potential (BMP) assays. Cyclic BMP assays indicated that using an appropriate fraction of recycled leachate and fresh make up water can stimulate methanogenic activity and enhance biogas production. Conversely increasing the percentage of recycled leachate in the make up water eventually causes methanogenic inhibition and decrease in the rate of food waste stabilization. The decrease in activity is exacerbated as the number cycles increases. Inhibition is possibly attributed to accumulation and elevated concentrations of ammonia as well as other waste by products in the recycled leachate that inhibit methanogenesis.