| 21. |
- Korsak, Larisa, et al.
(författare)
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Evaluation of anaerobic sludge activity in wastewater treatment plants in Nicaragua
- 2006
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Ingår i: Water Pollution VIII. - 184564042X ; , s. 571-579
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Konferensbidrag (refereegranskat)abstract
- Sludge of three municipal anaerobic wastewater treatment plants was evaluated. This study was initiated due to the low activity observed in the anaerobic wastewater treatment plants in Nicaragua. An additional goal to select one of them, if possible, as an inoculum for the brewery treatment plant was proposed. Two of these plants work with an Imhoff tank and one with a Septic tank followed by an anaerobic upflow filter. The study consisted in the characterization of biomass in terms of Specific Methanogenic Activity (SMA), Volatile Suspended Solids (VSS), density, pH, and redox potential (RP). The treated waters were also analysed for nutrients, heavy metals and the organic load. The substrate used in the experiments for determining the methanogenic activity was acetic acid. NaHCO3 was added to maintain pH in the normal range of operation. The tests were carried out at a sludge load of 1.5 g VSS/l. The results indicate that treated wastewater does not have any impediment to proper development of microorganisms; no presence of toxic substances and enough essential nutrients were detected. The specific methanogenic activity of sludge (SMA) in the Imhoff tanks is relatively close and oscillates between 0.16-0.28 g CH4-COD/g VSS/day, and in the septic tank is 0.09 g CH4-COD/g VSS/day. These values agree with the methanogenic activity found in the literature for septic tanks (0.02-0.1 g CH4-COD/gVSS/day). The highest methanogenic activity measured during the test was 0.28g CH4-COD/g VSS/day in the sludge of the Imhoff tank in The Viejo city, so this sludge could be proposed as a seed for the brewery treatment plant.
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| 22. |
- Zapata Campos, María José, 1972, et al.
(författare)
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Global narratives of sustainable waste governance in Managua, Nicaragua
- 2011
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Ingår i: Globalization and Development: Rethinking Interventions and Governance.
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Konferensbidrag (refereegranskat)abstract
- Waste is one of the glocal meta-problems and as such an issue for both global and local governance. While waste is a global fluid, with the risks and profitability associated to its movement, it is also an extremely localized phenomenon (Honor Fagan, 2003). The notion of waste is a construct. Its meaning varies between places and societies at different times (MacKillop, 2009); as does the way societies engage with their waste and deal with it. In the last decades waste governance has being constructed as a sustainability problem for both the global North and the global South. A significant number of international multi-lateral organisations are concerned with the issue of sustainable waste governance, bringing global ideas from the North to the South. Most international and national development aid organisations (e.g. UNEP, UN-Habitat, UE …) carry out development projects, programs and experiences of transference of knowledge and best practices regarding a sustainable waste governance. These discourses of what sustainable waste governance is generated by global organisations shape the local practices for the organizing of waste. The definition, problematisation, policies, plans, technologies and management models used for the governing of waste locally is affected considerably by the discourses within and amongst these global organisations, as are the practices of sustainability they propose and promote. However, the global discourse of a sustainable waste management is neither unique nor uniform. The multiplicity of global actors hence leads to a multiplicity of narratives and discourses on sustainable waste governance. In this paper we aim at exploring some of the many global narratives of waste governance in order to unfold how these views pervade local waste governance and policies. In order to do that the paper focus on the case study of Managua, in Nicaragua, and the six development projects funded by different international aid development organisations (Spanish and Italian Aid Agencies, UN-Habitat, US-AID, European Union URBAL, PNUD) related to the city waste governance. Our data consist of policy documents from these organisations supported by personal interviews with key actors related to these projects and non-participant observations over a multitude of meetings and events. After presenting the different global narratives of waste governance in the findings section, we discuss in the conclusions how predominant global waste narratives have stabilized in the discourse of an urban sustainable development in Managua. We end the paper by contextualizing the conclusions with the concepts, assumptions and practices that give shape to the policies and practices connected to ‘sustainable development’
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| 26. |
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| 27. |
- Bergkvist, Lisa, et al.
(författare)
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Carbon Sequestration Potential f Agroforestry Systems For Phytoremediation In Chinandega, Nicaragua
- 2018
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Ingår i: Linnaeus Eco-Tech 2018. ; , s. 211-211
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Greenhouse gases in the atmosphere have increased to earlier unrecorded levels, causing global climate change that increases GMT and threaten ecosystems and livelihoods. IPCC report suggest that agroforestry offers considerable carbon sequestration (c seq.) potential, especially for developing countries. The purpose of this study is to estimate the c seq. potential in different agroforestry systems suitable in Chinandega, Nicaragua - a deforested region where the ground is polluted by toxaphene and other POP:s. Three scenarios where studied; Shading system using Tectona grandis and Pogostemon cablin; Alley cropping using Erythrina poeppigiana and Ricinus communis and Silvopasture using Cordia alliodora and Brachiaria ruziziensis, the last scenario being divided into two subscenarios; unmanaged (grazed) and managed (harvested) grass. Calculations were performed using the modelling program CO2FIX v. 3.2, with a runtime of 100 years and assuming deforested area with no previous land use. Results show a significantly higher c seq. potential in Shading system (168/217 MgC/ha). Alley cropping yields 71 MgC/ha and Silvopasture results in 80/84 MgC/ha unmanaged and 65/70 MgC/ha managed. The higher number includes products from harvest. All scenarios show fluctuations over time due to thinning and harvesting practices. Phytoremediation potential of POPs has been shown in Ricinus communis and grass species. Soil c seq. is especially important to consider in longterm scenarios as this c seq. can be sustained over longer time. The inclusion of crop residue, the effect of grazing animals or changes in density of trees and crops and environmental fate of the toxic compounds need further assessment before considering large scale applications. Agroforestry practices could contribute to several benefits, including climate change mitigation and phytoremediation.
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| 30. |
- Garca, I., et al.
(författare)
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Removal of natural organic matter by conventional and enhanced coagulation in Nicaragua
- 2007
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Ingår i: Water Resources Management IV. - : WIT Press. - 9781845640743 ; , s. 399-409
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Konferensbidrag (refereegranskat)abstract
- Enhanced coagulation was applied to raw water from a drinking water plant in Nicaragua through bench scale jar test in order to reduce the presence of natural organic matter (NOM) and decrease the trihalomethanes (THMs) formation which has been linked to carcinogenic diseases. Due to the lack of information about the presence of chlorination by-products (CBPs) like trihalomethanes, a study of their formation by varying pH, contact time, temperature and chlorine dose was also performed; following conventional or enhanced coagulation treatment. The results show that enhanced coagulation decreases considerably the formation of THMs because it reduces strongly the presence of organic matter due to the fact that higher alum doses were used in comparison with conventional coagulation utilized at the facility. The removal of dissolved organic carbon (DOC) was improved from 44 at the facility to 67 with enhanced coagulation. Trihalomethanes concentration increases drastically when extreme conditions of the four parameters evaluated were applied exceeding the maximum contaminant levels of USEPA (80 g/L) but not the Nicaraguan target value (460 g/L) for both coagulation types.
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