Refinar búsqueda
Resultados 1-10 de 12
Examining the role of estrogenic activity and ocean temperature on declines of a coastal demersal flatfish population near the municipal wastewater outfall of Orange County, California, USA
2018
Andrzejczyk, Nicolette | Sakamoto, Ken | Armstrong, Jeff | Schlenk, Daniel
Wastewater treatment plant effluent introduces a mixture of pollutants into marine environments; however, the impacts of chronic sublethal exposures on populations are often unclear. Presence of estrogenic agents in sediments and uptake of these compounds by demersal flatfishes has been reported at the Orange County Sanitation District (OCSD) wastewater outfall. Furthermore, estrogenic activity has been identified in male flatfish in the area, potentially contributing to observed population declines in the OCSD region. Rising ocean temperatures may further contribute to flatfish declines as relationships between temperature and abundance have been reported in the Southern California Bight. To investigate declines, sex ratios, condition factor, organ health indices, hormones, and vitellogenin were quantified in flatfish collected at OCSD outfall and reference sites. Additionally, historical temperature data was examined for trends with population abundances. Rather than being linked to estrogenic activity, results indicated that population declines were more correlated to increases in ocean temperature.
Mostrar más [+] Menos [-]The dependency analysis between energy consumption, sanitation, forest area, financial development, and greenhouse gas: a continent-wise comparison of lower middle-income countries
2018
Khan, Muhammad Tariq Iqbal | Yaseen, Muhammad Rizwan | Ali, Qamar
This study explored the long-run association among greenhouse gases (GHGs), financial development, forest area, improved sanitation, renewable energy, urbanization, and trade in 24 lower middle-income countries from Asia, Europe, Africa, and America (South and North) by using panel data from 1990 to 2015. Granger causality was tested by Toda and Yamamoto approach. The bi-directional causality was established among urbanization and GHGs (Asia), financial development and forest (Asia), energy use and renewable energy (Asia), renewable energy and forest (Asia), improved sanitation and forest (Asia, Africa, America), urbanization and forest (Asia), and improved sanitation and financial development (Europe). The GHG emission also shows one-way causality is running from financial development to GHG (America), energy to GHG (Asia), renewable energy to GHG (America), forest area to GHG (America), trade openness to GHG (Africa), urbanization to GHG (Europe), GHG to financial development (Europe), GHG to energy use (Europe, Africa, and America), and GHG to trade openness (Asia). On the basis of fully modified ordinary least square and generalized method of moment, the reciprocal relationship of GHGs was observed due to financial development in Asia and Africa; renewable energy in all panels; forest area in Asia, Europe, and America; improved sanitation in Asia, Africa, and America; trade openness in Africa; and urbanization in Europe and America. Policymakers should concentrate on these variables for the reduction in GHGs. The annual convergence towards long-run equilibrium was 50.5, 31.9, and 20.9% for America, Asia, and Africa, respectively.
Mostrar más [+] Menos [-]Using a Numerical Model to Track the Discharge of a Wastewater Treatment Plant in a Tidal Estuary
2018
True, Ernest D.
Along the coast of Maine, USA, there are numerous wastewater treatment plants that discharge their treated effluents into a river estuary which is shared by commercial fishing and shellfish harvesting. Occasionally, there can be failures or bypasses of treatment plants that lead to untreated or partially treated sewage flowing into shellfish harvesting waters. To prevent any toxic contamination of harvested shellfish, a prohibitive zone is established around the treatment plant where shellfish harvesting is prohibited. The U.S. Food and Drug Administration has conducted numerous dye studies on both coasts of the USA to determine these prohibitive zones, based on the guidelines of the National Shellfish Sanitation Program. In May 2010, the FDA conducted such a dye study at the Yarmouth, Maine wastewater treatment plant. The results are compared with a numerical coastal model that provides the velocity field for the currents around the treatment plant. This model includes a diffusion equation to simulate dye dispersion from a point source which is used to determine the prohibitive zone. The numerical model shows good correlation with the FDA dye study report and establishes a prohibitive zone for commercial harvesting in keeping with that of the FDA study. The benefits of the numerical model include sampling at thousands of locations simultaneously, seasonal changes in river volumes, and changes in plant discharge volumes.
Mostrar más [+] Menos [-]Wetlands for wastewater treatment and subsequent recycling of treated effluent: a review
2018
Almuktar, Suhad A. A. A. N. | Abed, Suhail N. | Scholz, Miklas
Due to water scarcity challenges around the world, it is essential to think about non-conventional water resources to address the increased demand in clean freshwater. Environmental and public health problems may result from insufficient provision of sanitation and wastewater disposal facilities. Because of this, wastewater treatment and recycling methods will be vital to provide sufficient freshwater in the coming decades, since water resources are limited and more than 70% of water are consumed for irrigation purposes. Therefore, the application of treated wastewater for agricultural irrigation has much potential, especially when incorporating the reuse of nutrients like nitrogen and phosphorous, which are essential for plant production. Among the current treatment technologies applied in urban wastewater reuse for irrigation, wetlands were concluded to be the one of the most suitable ones in terms of pollutant removal and have advantages due to both low maintenance costs and required energy. Wetland behavior and efficiency concerning wastewater treatment is mainly linked to macrophyte composition, substrate, hydrology, surface loading rate, influent feeding mode, microorganism availability, and temperature. Constructed wetlands are very effective in removing organics and suspended solids, whereas the removal of nitrogen is relatively low, but could be improved by using a combination of various types of constructed wetlands meeting the irrigation reuse standards. The removal of phosphorus is usually low, unless special media with high sorption capacity are used. Pathogen removal from wetland effluent to meet irrigation reuse standards is a challenge unless supplementary lagoons or hybrid wetland systems are used.
Mostrar más [+] Menos [-]The search for an alternative to piped water and sewer systems in the Alaskan Arctic
2018
Hickel, Korie A. | Dotson, Aaron | Thomas, Timothy K. | Heavener, Mia | Hébert, Jack | Warren, John A.
Forty-two communities in rural Alaska are considered unserved or underserved with water and sewer infrastructure. Many challenges exist to provide centralized piped water and sewer infrastructure to the homes, and they are exacerbated by decreasing capital funding. Unserved communities in rural Alaska experience higher rates of disease, supporting the recommendation that sanitation infrastructure should be provided. Organizations are pursuing alternative solutions to conventional piped water and sewer in order to maximize water use and reuse for public health. This paper reviews initiatives led by the State of Alaska, the Alaska Native Tribal Health Consortium, and the Yukon Kuskokwim Health Corporation to identify and develop potential long-term solutions appropriate and acceptable to rural communities. Future developments will likely evolve based on the lessons learned from the initiatives. Recommendations include Alaska-specific research needs, increased end-user participation in the design process, and integrated monitoring, evaluation, and information dissemination in future efforts.
Mostrar más [+] Menos [-]Cadmium, mercury, and nickel adsorption by tetravalent manganese feroxyhyte: selectivity, kinetic modeling, and thermodynamic study
2018
Kokkinos, Evgenios | Soukakos, Konstantinos | Kostoglou, Margaritis | Mitrakas, Manassis
This study is aiming to investigate tetravalent manganese feroxyhyte (TMFx) adsorption efficiency in removing heavy metals. The motivation of this study was the fact that TMFx is a highly negatively charged nanostructure material and that the metals Cd, Hg, and Ni were characterized as priority pollutants for drinking water. TMFx was evaluated through batch and continuous flow experiments in National Sanitation Foundation (NSF) water matrix which simulated the physicochemical characteristics of natural water. Water’s pH significantly influences Cd and Ni adsorption efficiency which gradually increases when pH value rises from 5 to 9, while the corresponding one for Hg remains almost constant. Thermodynamic data showed a spontaneous and an exothermic nature weak-chemisorption (ΔΗ° = −17.5 ± 2 kJ/mol) of Cd, Ni, and Hg by TMFx. The determined ranking of adsorption affinity and selectivity (Cd > Ni > Hg) seems to be governed by the metals’ speciation, as well as by hydration free energy, which is influenced, however, by their atomic radius. The lower adsorption capacity and selectivity of TMFx for Hg should be attributed both to uncharged species and to higher atomic radius. The similar Cd and Ni speciation in the NSF water matrix leads to the conclusion that the better affinity, selectivity, and adsorption kinetic of Cd versus Ni should be attributed to the lower hydration free energy of Cd which is in turn related to its higher atomic radius. The faster adsorption kinetic (Hg > Cd > Ni) of Hg may be attributed to the lower radius of its anhydrate species. Furthermore, TMFx showed high removal efficiency under continuous flow application in an adsorption bed setup. The determined uptake capacity (q RL) at equilibrium-breakthrough concentration equal to the drinking water regulation limit (RL) of each metal were q ₁ = 2.5 μg Hg/mg TMFx, q ₅ = 5.2 μg Cd/mg TMFx, and q ₂₀ = 7.1 μg Ni/mg TMFx. Leaching tests of spent TMFx samples from the rapid small-scale column tests (RSSCTs) could be treated either as inert wastes after Cd and Ni adsorption or as non-hazardous waste after Hg adsorption.
Mostrar más [+] Menos [-]Greenlandic water and sanitation—a context oriented analysis of system challenges towards local sustainable development
2018
Hendriksen, Kåre | Hoffmann, Birgitte
Today, as Greenland focuses on more economic and cultural autonomy, the continued development of societal infrastructure systems is vital. At the same time, pressure is put on the systems by a lack of financial resources and locally based professional competences as well as new market-based forms of organization. Against this background, the article discusses the challenges facing Greenland’s self-rule in relation to further develop the existing water and wastewater systems so that they can contribute to the sustainable development of Greenland. The article reviews the historical development of the water supply and wastewater system. This leads to an analysis of the sectorisation, which in recent decades has reorganized the Greenlandic infrastructures, and of how this process is influencing local sustainable development. The article discusses the socio-economic and human impacts and points to the need for developing the water and sanitation system to support not only hygiene and health, but also local sustainable development.
Mostrar más [+] Menos [-]Greenlandic water and sanitation systems—identifying system constellation and challenges
2018
Hendriksen, Kåre | Hoffmann, Birgitte
A good water supply and wastewater management is essential for a local sustainable community development. This is emphasized in the new global goals of the UN Sustainable Development, where the sixth objective is to: “Ensure availability and sustainable management of water and sanitation for all” (United Nations 2015). This obviously raises the question of how this can be achieved considering the very different conditions and cultures around the globe. This article presents the Greenlandic context and elucidates the current Greenland water supply system and wastewater management system from a socio-technical approach, focusing on the geographic, climatic and cultural challenges. The article identifies a diverse set of system constellations in different parts of Greenland and concludes with a discussion of health and quality of life implications.
Mostrar más [+] Menos [-]How useful are geochemical and mineralogical indicators in assessing trace metal contamination and bioavailability in a post-restoration Mediterranean lagoon?
2018
Oueslati, Walid | Helali, Mohamed Amine | Mensi, Ikram | Bayaoui, Malek | Touati, Hiba | Khadraoui, Amani | Zaabooub, Noureddine | Added, Ayed | Aleya, Lotfi
Tunis’s Lake North (LNT), located on the Mediterranean Sea, and Tunisia’s most important lagoon due to its economic value and its strategic position within the city, has recently undergone a vast sanitation project. To study the lagoon’s level of metal pollution, three sediment cores were taken and the sediments were analyzed for trace and major elements, acid volatile sulfides (AVS), total organic carbon (TOC), and minerals. Results showed that TOC concentrations (0.2–3.1%) decreased following the lagoon’s restoration. In addition, in comparison to historical data, concentrations of Cu (16–69.5 μg g⁻¹), Zn (60.6–191.4 μg g⁻¹), and Pb (13–100.9 μg g⁻1) also decreased. Enrichment factor calculation with respect to the crust and local background showed that the sediment had long been contaminated by human pollution and especially by Pb, Zn, and Cu. The AVS to simultaneously extracted metal (SEM) ratio revealed values generally less than 1 indicating no sediment toxicity risks. Statistics revealed a detrital origin for certain metals and a diagenetic origin for FeS₂ and carbonate minerals.
Mostrar más [+] Menos [-]Rapid monitoring and evaluation of a community-led total sanitation program using smartphones
2018
Ravindra, Khaiwal | Mor, Suman
India accounts for around 50% of the world’s open defecation, and under a World Bank initiative, a rural district was selected to be the first open defecation-free (ODF) district in Punjab. Considering this, the current study aims to evaluate the application and impact of a smartphone-based instant messaging app (IMA) on the process of making Fatehgarh Sahib an ODF district. The District Administration involved the Water Supply and Sanitation Department, Non-government Organizations, and volunteers to promote the process of a community-led total sanitation. Proper training was provided to the volunteers to spread awareness about the triggering events, health impacts of open defecation, and monetary benefits of building new individual household latrine (IHHL). IMA was used as an aid to speed up monitoring and for the evaluation of a sanitation program. All the volunteers were connected to an IMA. This helped in providing a transparent and evidence-based field report on triggering events, follow-up activities, validation of existing IHHL, and monitoring of construction of new IHHL. IMA is a cost-effective tool as it is already being used by the volunteers and requires no additional cost (on the user or on the project) but requires a training on ethical uses of mobile and data safety.
Mostrar más [+] Menos [-]