Rapid manganese removal from mine waters using an aerated packed-bed bioreactor

In the UK, the Environmental Quality Standard for manganese has recently been lowered to 30 microg/L (annual average), which is less than the UK Drinking Water Inspectorate's Maximum Permitted Concentration Value (50 microg/L). Current passive treatment systems for manganese removal operate as open-air gravel-bed filters, designed to maximize either influent light and/or dissolved oxygen. This requires large areas of land. A novel enhanced bioremediation treatment system for manganese removal has been developed that consists of a passively aerated subsurface gravel bed. The provision of air at depth and the use of catalytic substrates help overcome the slow kinetics usually associated with manganese oxidation. With a residence time of only 8 h and an influent manganese concentration of approximately 20 mg/L, >95% of the manganese was removed. The treatment system also operates successfully at temperatures as low as 4 degrees C and in total darkness. These observations have positive implications for manganese treatment using this technique in both colder climates and where large areas of land are unavailable. Furthermore, as the operation of this passive treatment system continually generates fresh manganese oxyhydroxide, which is a powerful sorbent for most pollutant metals, it potentially has major ancillary benefits as a removal process for other metals, such as zinc.     

Science in the public process of ecosystem management: lessons from Hawaii, Southeast Asia, Africa and the US Mainland

Partnerships and co-operative environmental management are increasing worldwide as is the call for scientific input in the public process of ecosystem management. In Hawaii, private landowners, non-governmental organizations, and state and federal agencies have formed watershed partnerships to conserve and better manage upland forested watersheds. In this paper, findings of an international workshop convened in Hawaii to explore the strengths of approaches used to assess stakeholder values of environmental resources and foster consensus in the public process of ecosystem management are presented. Authors draw upon field experience in projects throughout Hawaii, Southeast Asia, Africa and the US mainland to derive a set of lessons learned that can be applied to Hawaiian and other watershed partnerships in an effort to promote consensus and sustainable ecosystem management. Interdisciplinary science-based models can serve as effective tools to identify areas of potential consensus in the process of ecosystem management. Effective integration of scientific input in co-operative ecosystem management depends on the role of science, the stakeholders and decision-makers involved, and the common language utilized to compare tradeoffs. Trust is essential to consensus building and the integration of scientific input must be transparent and inclusive of public feedback. Consideration of all relevant stakeholders and the actual benefits and costs of management activities to each stakeholder is essential. Perceptions and intuitive responses of people can be as influential as analytical processes in decision-making and must be addressed. Deliberative, dynamic and iterative decision-making processes all influence the level of stakeholder achievement of consensus. In Hawaii, application of lessons learned can promote more informed and democratic decision processes, quality scientific analysis that is relevant, and legitimacy and public acceptance of ecosystem management.     

Beyond ‘just’ flood risk management: the potential for—and limits to—alleviating flood disadvantage

Regional Environmental Change - The threat of flooding poses a considerable challenge for justice. Not only are more citizens becoming exposed to risk, but they are expected to play increasingly...     

Solar driven nitrous acid formation on building material surfaces containing titanium dioxide: A concern for air quality in urban areas?

The photoenhanced uptake of nitrogen dioxide (NO₂) to the surface of commercially available self-cleaning window glass has been studied under controlled laboratory conditions. This material is one of an array of modern building products which incorporate titanium dioxide (TiO₂) nanoparticles and are finding increasing use in populated urban areas. Amongst the principal drivers for the use of these materials is that they are thought to facilitate the irreversible removal of pollutants such as NO₂ and organic molecules from the atmosphere and thus act to remediate air quality. While it appears that TiO₂ materials do indeed remove organic molecules from built environments, in this study we show that the photoenhanced uptake of NO₂ to one example material, self-cleaning window glass, is in fact accompanied by the substantial formation (50–70%) of gaseous nitrous acid (HONO). This finding has direct and serious implications for the use of these materials in urban areas. Not only is HONO a harmful respiratory irritant, it is also readily photolysed by solar radiation leading to the formation of hydroxyl radicals (OH) together with the re-release of NO_x as NO. The net effect of subsequent OH initiated chemistry can then be the further degradation of air quality through the formation of secondary pollutants such as ozone and VOC oxidation products. In summary, we suggest that a scientifically conceived technical strategy for air quality remediation based on this technology, while widely perceived as universally beneficial, could in fact have effects precisely opposite to those intended.     

Effect of interior door position on room-to-room differences in residential pollutant concentrations after short-term releases

Residential interior door positions influence the pollutant concentrations that result from short-term indoor sources, such as cigarettes, candles, and incense. To elucidate this influence, we reviewed past studies and conducted new experiments in three residences: a single-story 714 m³ ranch-style house, a 510 m³ two-story split-level house, and a 200 m³ two-story house. During the experiments, we released sulfur hexafluoride or carbon monoxide tracer gas over short periods (≤30 min) and measured concentrations in the source room and at least one other (receptor) room for various interior door opening positions. We found that closing a door between rooms effectively prevented transport of air pollutants, reducing the average concentration in the receptor room relative to the source room by 57–100% over exposure periods of 1–8 h. When intervening doors were partially or fully open, the reduction in average concentrations ranged from 3% to 99%, varying as a function of door opening width and the distance between source and receptor rooms.     

Adopting and applying eco-design techniques: a practitioners perspective

This paper discusses the findings of a small scale research project which explored the possibility of adopting eco-design techniques. The paper focuses on identifying how eco-design techniques can be determined as being compatible with new product development processes. Via the development of a five stage ‘applicability framework’, this study demonstrates how a compatible suite of tools can be identified for application to product development processes. Testing and validation of this ‘applicability framework’, which was used to identify three key eco-design techniques; namely checklists, guidelines, and a material, energy and toxicity (MET) matrix, is shown to have taken place in relation to the development of a lightweight chemical detector product. It is established that checklists, guidelines and the MET matrix can be used both on a specific product, and also more generally in the design process. In particular, the MET matrix is shown as being used to successfully identify key environmental aspects of the product during its lifetime. The paper concludes by arguing that eco-design techniques may not have been more widely adopted by businesses because such methods are not necessarily generic and immediately applicable, but instead require some form of process-specific customisation prior to use, which can in turn act as a barrier to adoption. It is also highlighted that the shear diversity of pressures that come to bear during the product development process can also act as a barrier to adoption, and that the full integration of eco-design techniques will have to encompass approaches which overcome such pressures.     

Inception of formation and early morphogenesis of the bacterial light organ of the sea urchin cardinalfish, <Emphasis Type="Italic">Siphamia versicolor</Emphasis>

The cardinalfish Siphamia versicolor (Perciformes: Apogonidae) forms a bioluminescent symbiosis with the marine luminous bacterium Photobacterium mandapamensis, harboring the bacteria in a ventral, disc-shaped light organ and using the bacterial light apparently for counterillumination and attracting prey. Little definitive information has been available on the developmental and microbiological events surrounding the initiation of symbiosis, a critical stage in the life history of the fish, in S. versicolor or any of the many other species of bacterially luminous fish. To identify the stage at which light organ formation begins, to determine the origin of cells forming the light organ, and to characterize its bacterial colonization status during development, early developmental stages of S. versicolor obtained and reared from wild-caught mouth-brooding males were examined with histological and microbiological methods. A light organ primordium was not evident in embryos, post-embryos, or pre-release larvae, whereas the light organ began to form within 1 day of release of full-term pre-flexion larvae from the mouths of male fish. Analysis of post-release larvae revealed that the light organ arises from a proliferation and differentiation of intestinal epithelial cells, and that it quickly develops structural complexity, including the formation of chambers and gaps contiguous with the intestinal epithelium. However, the nascent light organ remained uncolonized by the symbiotic bacteria through several days of post-release development, even in the presence of high numbers of the symbiotic bacteria. These results demonstrate that the inception of light organ formation in S. versicolor occurs independently of its symbiotic bacteria and that receptivity to bacterial colonization apparently requires substantial post-release development of the light organ. Larvae therefore most likely acquire their symbiotic bacteria from seawater, during or shortly after the transition from the pre-flexion to the flexion developmental stage.     

Assessment of the environmental profile of PLA,PET and PS clamshell containers using LCA methodology

Life cycle assessments of bio-based polymer resin and products historically have shown favorable results in terms of environmental impacts and energy use compared to petroleum-based products. However, calculation of these impacts always depends on the system and boundary conditions considered during the study. This paper reports a cradle-to-cradle Life Cycle Assessment (LCA) of poly(lactic acid) (PLA) in comparison with poly(ethylene terephthalate) (PET) and poly(styrene) (PS) thermoformed clamshell containers, used for packaging of strawberries with emphasis on different end-of-life scenarios. It considers all the inputs such as fertilizers, pesticides, herbicides and seed corn required for the growing and harvesting of corn used for manufacturing PLA. For PET and PS, the extraction of crude oil and the entire cracking processes from crude oil through styrene and ethylene glycol and terephathalic acid are considered. Global warming, aquatic acidification, aquatic eutrophication, aquatic ecotoxicity, ozone depletion, non-renewable energy and respiratory organics, land occupation and respiratory inorganics were the selected midpoint impact categories. The geographical scope of the study reflects data from Europe, North America and the Middle East. PET showed the highest overall values for all the impact categories, mainly due to the higher weight of the containers. The main impacts to the environment were the resin production and the transportation stage of the resins and containers. This implies that the transportation stage of the package is an important contributor to the environmental impact of the packaging systems, and that it cannot be diminished.