Bioleaching of Copper from Electronic Waste Using Aspergillus niger

The recycling of printed circuit boards (PCBs) causes environmental problems by releasing dioxins and furans. The objective of this study is the recovery of copper from PCBs through the bioleaching process using Aspergillus niger which was isolated from the surface of Abu Tartur phosphate. In the bioleaching process, the optimum conditions were used to modify ammonium medium with inoculum spore size are 2Χ106 SFU/50 ml for 5 days at 30ͦ C in a pulp of 0.5% solid 150 mesh particle size and aeration at 200 rpm. Different carbon and nitrogen sources were used. Glucose (1.5%) and ammonium chloride (0.2%) were the best source of carbon and nitrogen, respectively. Also, the optimum initial medium’s pH was 7. At these conditions, about 100% of Cu was extracted. The mechanism of bioleaching was studied by detecting the production of organic acid through using brome cresol green as an indicator and HPLC analysis. The color change of agar medium of the incubated plate with A. niger from blue to yellow, and HPLC analysis showed detection malic and citric acids in the sample in presence e-waste higher than the sample without e-waste. E-waste before and after the bioleaching process was investigated using SEM. The surface of e-waste becomes more smooth and porous due to the bioleaching process.

Combination of methods of thermal and radiation treatment of sediments associated with PCBs – the Delor type

An efficient method of burning polychlorinated biphenyls (PCBs) is often used to remove the environmental burden of PCBs. However, combustion produces toxic dioxins and furans (PCDD/F), so residents are increasingly rejecting this method. The heat treatment (HT) method does not burn PCBs but evaporates it from sediments. Even in this process, PCDD/Fs are formed to a lesser extent, which are destroyed by radiation processing (RP) following the HT. At the same time, the RP method degrades PCB congeners down to biphenyls, which decompose easily in the environment. A block assembly of a complex synergistic combination of equipment for methods of thermal (HT) and radiation (RP) destruction of PCBs in sediments is proposed. The efficacy of this complex was preliminarily determined at a level of 70-fold reduction in PCB concentration in sediments. To achieve a higher reduction factor in the concentration of PCBs, possible procedures for optimizing the settings of individual devices of this complex are presented.

Aspects Regarding Polluting Emissions to the Stack of Clincher Ovens in Romanian Cement Factories

The paper presents an analysis of the flow of flue gases and dust in the area of the clinker kiln and in the area of the flour mill, as well as emission data for the last three consecutive years at the flour mill stack - clinker kiln, from some cement factories in Romania. In general, both emissions of dust (total powders) and pollutant gases (SOx, NOx, CO, dioxins and furans, VOC, heavy metals, etc.) were within the permissible limits set out in the Integrated Environmental Permit of the individual plants.

Determination of Formaldehyde from Disposal of Formaldehyde Fixed Biological Specimen Buried in Soil

Biomedical waste specifically anatomical specimens and body parts will be incinerated by a local incineration facility. However, the incineration of formaldehyde fixed specimen from hospitals poses hazardous effect to human and environment due to an exposure of highly toxic gases such as dioxins and furans. In addition, this practise is considered as non-shariah compliance by Muslim community. Thus, a safer and shariah-compliance option to dispose anatomical specimens through deep burial has been introduced. The concern has been raised on the side effect of the formaldehyde treated specimen to the environment. Formaldehyde is used widely for preservation of surgical and anatomical specimens. The formaldehyde toxicity specifically on the soil, soil water, soil animals and plants should be considered after the burial of the anotamical specimens. Thus, the aim of this study was to investigate the side effect of formaldehyde on soil after the burial of formalin fixed specimen on the environment. In this study, the amount of soil elemental distribution and formaldehyde concentration of pre-burial and post-burial of biological specimen were evaluated by using Energy Dispersive X-Ray Fluorescence (EDXRF) and Ultraviolet-Visible Spectrophotometer instrument, respectively. For EDXRF analysis at Point C, soil elemental distribution after burial of dead biological specimens has higher concentration compared to before the burial. The concentration of formaldehyde at Point C was higher after the burial of dead biological specimen compared to before burial, which exceeds the tolerable concentration recommended by the World Health Organisation (WHO).

PAH and POP Presence in Plastic Waste and Recyclates: State of the Art

The presence of different pollutants in recycled plastics is reviewed in this article. The desirable circular economy of plastics should be linked to the availability of clean recycled plastics with a non-significant and small to nil amount of substances of concern. Different researchers found polycyclic aromatic hydrocarbons (PAHs) and Persistent Organic Pollutants (POPs), such as brominated flame retardants (BFRs), pesticides, dioxins and furans (PCDD/Fs and PBDD/Fs) in plastic recyclates. This represents an added difficulty to the effective recycling process of plastics that reduces the demand for energy and materials, in addition to posing a great environmental danger since they represent a vector of accumulation of the contaminants that will finally appear in the most unexpected products. Life Cycle Analysis of the plastic wastes recycling process indicates a great saving of energy, water and CO2 emissions.

A Physiologically-Based Pharmaco-Kinetic Model For Disposition Of Dioxins And Furans In Fish

A Physiologically Based Pharmacokinetic (PBPK) model was developed for the disposition of dioxins in various fish species. The model was developed based on available information on the mechanisms of uptake, distribution, storage and elimination of dioxins in various species (other than fish) and empirical data on disposition of dioxins in the fish tissues. Two versions of the model were implemented: one for exposure to dioxins in water through the gill and the other one for exposure through food. Model compartments included the gill, kidney, liver and other richly-perfused tissues, as well as fat and other slowly-perfused tissues. In the food exposure version, the gut was also included as a richly-perfused tissue. The water exposure model was calibrated using two independent data sets for exposure of fathead minnow and medaka to 2,3,7,8-TCDD in water. The estimated parameter values in the two data sets were comparable and the predictions agreed with the observations very well. The results were compared to those produced by the default methods (bioconcentration factors). Uncertainty in the model prediction as a result of variability in input parameters was also discussed for the parameters with the highest impacts on the model outcome. The predictions of the food pathway exposure model were compared to data for rainbow trout liver.

A Physiologically-Based Pharmaco-Kinetic Model For Disposition Of Dioxins And Furans In Fish

A Physiologically Based Pharmacokinetic (PBPK) model was developed for the disposition of dioxins in various fish species. The model was developed based on available information on the mechanisms of uptake, distribution, storage and elimination of dioxins in various species (other than fish) and empirical data on disposition of dioxins in the fish tissues. Two versions of the model were implemented: one for exposure to dioxins in water through the gill and the other one for exposure through food. Model compartments included the gill, kidney, liver and other richly-perfused tissues, as well as fat and other slowly-perfused tissues. In the food exposure version, the gut was also included as a richly-perfused tissue. The water exposure model was calibrated using two independent data sets for exposure of fathead minnow and medaka to 2,3,7,8-TCDD in water. The estimated parameter values in the two data sets were comparable and the predictions agreed with the observations very well. The results were compared to those produced by the default methods (bioconcentration factors). Uncertainty in the model prediction as a result of variability in input parameters was also discussed for the parameters with the highest impacts on the model outcome. The predictions of the food pathway exposure model were compared to data for rainbow trout liver.