Optimization of metal bio-acid leaching from mobile phone printed circuit boards using natural organic acids and H2O2

Journal of Material Cycles and Waste Management - With increased popularity and technological innovation, more and more electric and electronic equipment wastes (e-wastes) are being generated....     

Determining and evaluating the thermodynamic properties of municipal solid waste for different provinces of Iran

Journal of Material Cycles and Waste Management - To study, analyze and select the appropriate method for converting MSW into energy, the thermodynamic properties of the MSW are required including...     

What is an explosion? A case history of an investigation for the insurance industry

After a large property loss, the insured and insurers of a hydroelectric power plant in North America became embroiled in subrogation to determine if the event could be characterized as an explosion. The subject insurance policy provided coverage for explosions, but excluded mechanical breakdowns. Analysis by Exponent Failure Analysis Associates indicated that a consistent, cross-disciplinary definition for explosions can be extracted from published scientific literature, and that this incident was not an explosion because certain key requirements were missing during the accident. However, this investigation has highlighted the necessity for insurance companies and their insureds to better understand this term and thereby minimize future coverage disputes. This paper presents an analysis of this incident and describes the necessary characteristics of an explosion.     

Evaluation of membrane bioreactor for hypersaline oily wastewater treatment

Produced water is a significant waste stream generated in association with oil and gas production. It contains high concentrations of hydrocarbon constituents and different salts. In this study, a membrane sequencing batch reactor (MSBR) was used to treat synthetic and real produced water. The MSBR was evaluated in terms of biodegradation of hydrocarbons in the synthetic produced water with various organic loading rates (OLR) (0.281, 0.563, 1.124, 2.248, and 3.372 kg COD/(m³ day)), cycle time (12, 24, and 48 h), and membrane performance. The effects of salt concentrations at different total dissolved solids (TDS) (35,000, 50,000, 100,000, 150,000, 200,000, and 250,000 mg/L) on biological treatment of the pollutants in the synthetic and real wastewater were studied. At an OLR of 1.124 kg COD/(m³ day), an HRT of 48 h and TDS of 35,000 mg/L, removal efficiencies of 97.5%, 97.2%, and 98.9% of COD, total organic carbon (TOC), and oil and grease (O&G), respectively were achieved. For the real produced water, removal rates of 86.2%, 90.8%, and 90% were obtained for the same conditions. However, with increasing salt content, the COD-removal efficiencies of the synthetic and real produced water were reduced to 90.4% and 17.7%, respectively at the highest TDS.     

Impacts of land use and land cover change on the interactions among multiple soil-dependent ecosystem services (case study: Jiroft plain,Iran)

The spatial and temporal distribution pattern is an outstanding feature of the relationship among ecosystem services (ESs) that explains links between human activities and disturbed chemical composition of ecosystems. This study investigated the spatiotemporal variation of land use/cover changes (LUCC) and quantifies the change in four essential ecosystem services with an emphasis on soil (nutrient delivery ratio, carbon storage, crop production, and water yield) and their relationships in the Jiroft plain, Iran, during 1996–2016 through analytical tools including Land Change Modeler, and the Integrated Valuation of Ecosystem Services and Tradeoff. During the 20-year concentrate period, there was a considerable overall gain in cropland (5396 km²) and urban (1787 km²), loss of unused land (5692 km²), water (2088 km²), and forest (1083 km²). As a result of LUCC, while crop production and nutrient delivery ratio showed a rising trend, overall carbon storage and water yield decreased. The spatiotemporal trade-off between carbon storage and crop production, the temporal trade-off between crop production and water yield, and synergy between water yield and crop production were widespread in Jiroft plain. These results showed that the interaction among ESs mutates over time and can be changed under planning and policies. This study will enrich the research of the geographical distribution of ESs interaction in dryland ecosystems to provide practical ecosystem management under local conditions.

     

Oxidative potential (OP) and mineralogy of iron ore particulate matter at the Gol-E-Gohar Mining and Industrial Facility (Iran)

Concentrations of total suspended particulate matter, particulate matter with aerodynamic diameter <2.5 μm (PM_2.5), particulate matter <10 μm (PM₁₀), and fallout dust were measured at the Iranian Gol-E-Gohar Mining and Industrial Facility. Samples were characterized in terms of mineralogy, morphology, and oxidative potential. Results show that indoor samples exceeded the 24-h PM_2.5 and PM₁₀ mass concentration limits (35 and 150 µg m^?3, respectively) set by the US National Ambient Air Quality Standards. Calcite, magnetite, tremolite, pyrite, talc, and clay minerals such as kaolinite, vermiculite, and illite are the major phases of the iron ore PM. Accessory minerals are quartz, dolomite, hematite, actinolite, biotite, albite, nimite, laumontite, diopside, and muscovite. The scanning electron microscope structure of fibrous-elongated minerals revealed individual fibers in the range of 1.5 nm to 71.65 µm in length and 0.2 nm to 3.7 µm in diameter. The presence of minerals related to respiratory diseases, such as talc, crystalline silica, and needle-shaped minerals like amphibole asbestos (tremolite and actinolite), strongly suggests the need for detailed health-based studies in the region. The particulate samples show low to medium oxidative potential per unit of mass, in relation to an urban road side control, being more reactive with ascorbate than with glutathione or urate. However, the PM oxidative potential per volume of air is exceptionally high, confirming that the workers are exposed to a considerable oxidative environment. PM released by iron ore mining and processing activities should be considered a potential health risk to the mine workers and nearby employees, and strategies to combat the issue are suggested.     

The implementation of data reconciliation for evaluating a full-scale petrochemical wastewater treatment plant

Data reconciliation and mass balance analysis were conducted for the first time to improve the data obtained from a petrochemical wastewater treatment plant (WWTP), and the results were applied to evaluate the performance of the plant. Daily average values for 209 days from the inlet and outlet of the plant obtained from WWTP documentation center along with the results of four sampling runs in this work were used for data reconciliation and performance evaluation of the plant. Results showed that standard deviation and relative errors in the balanced data of each measurement decreased, especially for the process wastewater from 24.5 to 8.6 % for flow and 24.5 to 1.5 % for chemical oxygen demand (COD). The errors of measured data were −137 m³/day (−4.41 %) and 281 kg/day (7.92 %) for flow and COD, respectively. According to the balanced data, the removal rates of COD and 5-day biological oxygen demand (BOD₅) through the aeration unit were equal to 37 and 46 %, respectively. In addition, the COD and BOD₅ concentrations were reduced by about 61.9 % (2137 kg/day) and 78.1 % (1976 kg/day), respectively, prior to the biological process. At the same time, the removal rates of benzene, toluene, and styrene were 56, 38, and 69 %, respectively. The results revealed that about 40 % of influent benzene (75.5 kg/day) is emitted to the ambient air at the overhead of the equalization basin. It can be concluded that the volatilization of organic compounds is the basic mechanism for the removal of volatile organic compounds (VOCs) and it corresponds to the main part of total COD removal from the WWTP.

     

Water and waste load allocation in rivers with emphasis on agricultural return flows: application of fractional factorial analysis

In this paper, a new methodology is developed to handle parameter and input uncertainties in water and waste load allocation (WWLA) in rivers by using factorial interval optimization and the Soil, Water, Atmosphere, and Plant (SWAP) simulation model. A fractional factorial analysis is utilized to provide detailed effects of uncertain parameters and their interaction on the optimization model outputs. The number of required optimizations in a fractional factorial analysis can be much less than a complete sensitivity analysis. The most important uncertain inputs and parameters can be also selected using a fractional factorial analysis. The uncertainty of the selected inputs and parameters should be incorporated real time water and waste load allocation. The proposed methodology utilizes the SWAP simulation model to estimate the quantity and quality of each agricultural return flow based on the allocated water quantity and quality. In order to control the pollution loads of agricultural dischargers, it is assumed that a part of their return flows can be diverted to evaporation ponds. Results of applying the methodology to the Dez River system in the southwestern part of Iran show its effectiveness and applicability for simultaneous water and waste load allocation in rivers. It is shown that in our case study, the number of required optimizations in the fractional factorial analysis can be reduced from 64 to 16. Analysis of the interactive effects of uncertainties indicates that in a low flow condition, the upstream water quality would have a significant effect on the total benefit of the system.