Bioremediation of trace organic compounds found in precious metals refineries wastewaters: A review of potential options

Platinum group metal (PGM) refining processes produce large quantities of wastewater, which is contaminated with the compounds that make up the solvents/extractants mixtures used in the process. These compounds often include solvesso, β-hydroxyxime, amines, amides and methyl isobutyl ketone. A process to clean up PGM refinery wastewaters so that they could be re-used in the refining process would greatly contribute to continual water storage problems and to cost reduction for the industry. Based on the concept that organic compounds that are produced biologically can be destroyed biologically, the use of biological processes for the treatment of organic compounds in other types of waste stream has been favoured in recent years, owing to their low cost and environmental acceptability. This review examines the available biotechnologies and their effectiveness for treating compounds likely to be contained in precious metal extraction process wastewaters. The processes examined include: biofilters, fluidized bed reactors, trickle-bed bioreactors, bioscrubbers, two-phase partitioning bioreactors, membrane bioreactors and activated sludge. Although all processes examined showed adequate to excellent removal of organic compounds from various gaseous and fewer liquid waste streams, there was a variation in their effectiveness. Variations in performance of laboratory-scale biological processes are probably due to the inherent change in the microbial population composition due to selection pressure, environmental conditions and the time allowed for adaptation to the organic compounds. However, if these factors are disregarded, it can be established that activated sludge and membrane bioreactors are the most promising processes for use in the treatment of PGM refinery wastewaters

Biphenyl sorption to different soil clay minerals

Only limited information is available in the literature on the role of soil mineral surfaces in the sorption of hydrophobic organic pollutants. This knowledge gap is addressed through the assessment of biphenyl sorption to kaolinite, illite and bentonite; using the batch equilibration technique with incubations lasting 6 or 21 days at 28 ± 2°C in the dark [RT1]. Sorption of biphenyl onto kaolinite followed the Freundlich sorption isotherm, whereas linear sorption isotherms were observed on illite and bentonite [RT2]. The biphenyl sorption partition coefficient on kaolinite ranged from 0.1 to 9.1 cm3.g-1 after 6 days and no sorption was observed after 21 days. This could have been caused by a completely reversible sorption or a loss of binding capacity after 21 days [RT3]. The respective values of the biphenyl sorption partition coefficient on illite and bentonite ranged from 20.3 ± 0.3 to 120 ± 8 cm3.g-1.Sorption equilibrium on the internal clay surfaces was reached after 6 days, as indicated by the sorption data for illite and bentonite [RT4]. Access of biphenyl molecules to the internal clay surfaces is a function of the ionic strength of soil solution and the soil organic matter is the dominant site for biphenyl sorption after 6 to 21 days

The "old-new" challenges of water, sanitation and bioremediation in developing countries

Developing countries face challenges in the development of infrastructure and population growth. These lead to “side-effects" such as uncontrolled urbanization and the fact that basic services such as water and sanitation are lagging behind the actual needs on the ground. Historical challenges, lack of skilled staff and often lack of sustained funding are some of the reasons for the status quo. Extent of water and sanitation coverage often forces national and local governments to install the minimum-standard solutions, e.g. the ventilated improved pit latrines. This improves the public health status in the short-term, but causes problem in the long run due to the lack of regular maintenance such as through lack emptying of pits. Sometimes, construction of these facilities is of inferior standard. Pits are often built without lining or zero consideration is given to the local conditions in terms of soil properties, water table and the number of toilet users

Anaerobic digestion of fungally pre-treated wine distillery wastewater

The combination of fungal pre-treatment with Trametes pubescens and anaerobic digestion were tested for the removal of chemical oxygen demand (COD) and phenolic compounds from wine distillery wastewater. The COD removal efficiency after fungal pre-treatment reached 53.3%. During digestion, pH buffering was achieved using CaCO3 and K2HPO4. This provided a stable environment inside digester for efficient and time-independent COD removal. The total COD removal efficiency reached 99.5%, and the system proved able to eliminate shock COD loads, as indicated by the concentrations of sludge and volatile fatty acids. Complex changes of phenolic compounds are suspected in anaerobic digestionsystem, and are investigated further

Preliminary assessment of the gender aspects of disaster vulnerability and loss of human life in South Africa

South Africa has reached a medium level of human development and has a heterogeneous situation with respect to disaster risk management. In this article, a preliminary assessment of the gender aspects of disaster vulnerability and fatalities is presented. The United Nations, the Health Systems Trust and Statistics South Africa were used as data sources for the following gender-segregated values: the life expectancy at birth, unemployment rates, the human development index values, the maternal mortality rates and the number of deaths from unnatural and non-natural causes. The relevant inequality indices were then calculated and used to draw conclusions regarding the gender aspects of disaster risk management in South Africa. Results of the calculations indicate that between 1980 and 2011 men were 10% more vulnerable with respect to their health status. However, the gender differences have been decreasing in recent years. Access of women to healthcare is decreasing with time, potentially decreasing the recovery potential of whole families. Women are more economically vulnerable than men in South Africa, as they are 16.3% – 33% more likely to be unemployed than men. Educational status of both genders in South Africa is comparable based on literacy and enrolment rates at primary and secondary level. On the other hand, men are five times more likely to suffer fatal injuries during disasters

Anaerobic digestion of fungally pre-treated wine distillery wastewater

The combination of fungal pre-treatment with Trametes pubescens and anaerobic digestion were tested for the removal of chemical oxygen demand (COD) and phenolic compounds from wine distillery wastewater. The COD removal efficiency after fungal pre-treatment reached 53.3%. During digestion, pH buffering was achieved using CaCO3 and K2HPO4. This provided a stable environment inside digester for efficient and time-independent COD removal. The total COD removal efficiency reached 99.5%, and the system proved able to eliminate shock COD loads, as indicated by the concentrations of sludge and volatile fatty acids. Complex changes of phenolic compounds are suspected in anaerobic digestion system, and are investigated further

Between science, science-fiction and COVID19 as a way to interpret the ontological realm of COVID19.

The current article is an attempt by the authors to present a bioethical case, or rather a search being undertaken to develop tools to interpret the novel ontological realm which has been created, and continues to be transformed in real time, by the COVID19 pandemic and its aftermath. The ontological realm is new, but the physical features of the world and the human in it are partially constants and identical to the previous realm parameters, the pre-COVID19 space-time. The question of existence in the new ontological realm is...how can the continuum of Homo sapiens and its existence be sustained in this new realm? The tools being developed use of previous information and knowledge of the members of Homo sapiens as a starting point and source of metaphors as tools to facilitate existence in the new realm. In this way, existing knowledge, which is held by individual members of Homo sapiens, and which exists and continues being created in the continuum of Homo sapiens, can be the foundation for the creation of new knowledge about the post-COVID19 realm and the individual and collective comprehension of humans of it and in it. Conceptual metaphors, the creation of compound metaphor and the prospective dialectic are suggested by authors as a possible epistemic implementation mechanisms in this context. The adaptation of humanity, its imagination and some professions are used to demonstrate the case for the ‘new science of human existence’ in the post-COVID19 world

Biphenyl sorption to different soil clay minerals

Only limited information is available in the literature on the role of soil mineral surfaces in the sorption of hydrophobic organic pollutants. This knowledge gap is addressed through the assessment of biphenyl sorption to kaolinite, illite and bentonite; using the batch equilibration technique with incubations lasting 6 or 21 days at 28 ± 2°C in the dark [RT1]. Sorption of biphenyl onto kaolinite followed the Freundlich sorption isotherm, whereas linear sorption isotherms were observed on illite and bentonite [RT2]. The biphenyl sorption partition coefficient on kaolinite ranged from 0.1 to 9.1 cm3.g-1 after 6 days and no sorption was observed after 21 days. This could have been caused by a completely reversible sorption or a loss of binding capacity after 21 days [RT3]. The respective values of the biphenyl sorption partition coefficient on illite and bentonite ranged from 20.3 ± 0.3 to 120 ± 8 cm3.g-1.Sorption equilibrium on the internal clay surfaces was reached after 6 days, as indicated by the sorption data for illite and bentonite [RT4]. Access of biphenyl molecules to the internal clay surfaces is a function of the ionic strength of soil solution and the soil organic matter is the dominant site for biphenyl sorption after 6 to 21 days