552 research outputs found
Economic and environmental assessment of small and decentralized wastewater treatment systems
The aim of the present work was the assessment of economic and environmental aspects of decentralised
energy-saving wastewater treatment systems. The formulated investment and operation cost functions
were adjusted by a power law function. The different wastewater systems serving population settlements
between 50 p.e. and 250 p.e., presented associated investment costs varying from 400 €/p.e. to 200 €/p.e.
and annual operation costs in the range of 70 €/p.e. to 20 €/p.e., respectively. A Life Cycle Analysis
approach was used to compare the environmental impact alternative wastewater systems. The assessment
was focused on two energy-saving systems (constructed wetland and slow rate infiltration) and a
conventional one (activated sludge process). The low environmental impact of the energy-saving
wastewater treatment systems was demonstrated, being the most relevant the global warming indicator.
Options for reduction of life cycle impacts were assessed including materials used in construction and
operation lifetime of the systems. A 10 % extension of operation lifetime of constructed wetland and slow
rate infiltration systems lead to a 5 % and 7 % decrease in the abiotic depletion indicator, respectively,
and to a 1 % decrease in CO2 emissions in both systems. Replacing steel with HDPE in the activated
sludge tank resulted in a 1 % reduction in CO2 emission and 1 % in the abiotic depletion indicator. In the
case of the Imhoff tank a 1 % reduction in CO2 emissions and 5 % in abiotic depletion indicator were
observed when concrete was replaced by HDPE. Therefore, considering the huge potential of energy
saving wastewater treatment systems, the overall environmental impact of such design alternatives should
not be discarded.EU Program INTERREG III-B Atlantic Arc, Depuranat project (n.º 54)
Life cycle assessment of wastewater treatment options for small and decentralized communities
Sustainability has strong implications on the practice of engineering. Life cycle assessment (LCA)
is an appropriate methodology for assessing the sustainability of a wastewater treatment plant design. The
present study used a LCA approach for comparing alternative wastewater treatment processes for small and
decentralised rural communities. The assessment was focused on two energy-saving systems (constructed
wetland and slow rate infiltration) and a conventional one (activated sludge process). The low environmental
impact of the energy-saving wastewater treatment plants was demonstrated, the most relevant being the
global warming indicator. Options for reduction of life cycle impacts were assessed including materials used
in construction and operational lifetime of the systems. A 10% extension of operation lifetime of constructed
wetland and slow rate infiltration systems led to a 1% decrease in CO2 emissions, in both systems. The
decrease in the abiotic depletion was 5 and 7%, respectively. Also, replacing steel with HDPE in the
activated sludge tank resulted in a 1% reduction in CO2 emission and 1% in the abiotic depletion indicator.
In the case of the Imhoff tank a 1% reduction in CO2 emissions and 5% in the abiotic depletion indicator
were observed when concrete was replaced by HDPE.(undefined
Economic and environmental assessment of small and decentralized wastewater treatment systems
The aim of the present work was the assessment of economic and environmental aspects of
decentralized energy-saving wastewater treatment systems. The formulated investment and
operation cost functions were adjusted by a power law function. The different wastewater systems
serving population settlements between 50 p.e. and 250 p.e., presented associated investment
costs varying from €400/p.e. to €200/p.e. and annual operation costs in the range of €70/p.e.– €20/
p.e., respectively. A life cycle analysis approach was used to compare the environmental impact of
alternative wastewater treatment systems. The assessment was focused on two energy-saving
systems (constructed wetland and slow rate infiltration) and a conventional one (activated sludge
process). Low environmental impact of energy-saving wastewater treatment systems was
demonstrated, being the most relevant the global warming indicator. Options for reduction of life
cycle impacts were assessed including materials used in construction and operation lifetime of
the systems. A 10% extension of operation lifetime of constructed wetland and slow rate infiltration
systems lead to a 5% and 7% decrease in the abiotic depletion indicator, respectively, and to a 1%
decrease in CO2 emissions in both systems. Replacing steel with HDPE in the activated sludge
tank resulted in a 1% reduction in CO2 emission and 1% in the abiotic depletion indicator. In the
case of the Imhoff tank a 1% reduction in CO2 emissions and 5% in abiotic depletion indicator
were observed when concrete was replaced by HDPE. Therefore, considering the huge potential
of energy saving wastewater treatment systems, the overall environmental impact of such design
alternatives should not be discarded.EU Program INTERREG
III-B Atlantic Arc, Depuranat project (No. 54
Cost-effectiveness analysis for sustainable wastewater engineering and water resources management : a case study at Minho–Lima river basins (Portugal)
A cost-effectiveness integrated methodology applied in a water resources management and
sanitation project in Minho and Lima’s region (Portugal) is presented. First, environmental
objectives and programmes of measures (PM) are established and priorities are identified using a
cause–effect assessment matrix and a global effectiveness index. Aiming to achieve more demanding
goals, some complementary actions are considered, including “decentralized low-energy
wastewater treatment plants construction”. A geographic information system was used to select
potential implementation sites, and suitable treatment processes for each location are identified.
The centralized and decentralized wastewater treatment plants combination is promising, achieving
a cost-effectiveness attendance of €1510/equivalent-inhabitant in Minho–Lima river basins
EFHC1 variants in juvenile myoclonic epilepsy: reanalysis according to NHGRI and ACMG guidelines for assigning disease causality
Peer reviewe
Characteristics of Abnormal Diffusivity in Normal-Appearing White Matter Investigated with Diffusion Tensor MR Imaging in Tuberous Sclerosis Complex
Genetic signatures of parental contribution in black and white populations in Brazil
Two hundred and three individuals classified as white were tested for 11 single nucleotide polymorphisms plus two insertion/deletions in their Y-chromosomes. A subset of these individuals (n = 172) was also screened for sequences in the first hypervariable segment of their mitochondrial DNA (mtDNA). In addition, complementary studies were done for 11 of the 13 markers indicated above in 54 of 107 black subjects previously investigated in this southern Brazilian population. The prevalence of Y-chromosome haplogroups among whites was similar to that found in the Azores (Portugal) or Spain, but not to that of other European countries. About half of the European or African mtDNA haplogroups of these individuals were related to their places of origin, but not their Amerindian counterparts. Persons classified in these two categories of skin color and related morphological traits showed distinct genomic ancestries through the country. These findings emphasize the need to consider in Brazil, despite some general trends, a notable heterogeneity in the pattern of admixture dynamics within and between populations/groups
Structural and molecular correlates of cognitive aging in the rat
Aging is associated with cognitive decline. Herein, we studied a large cohort of old age and young adult male rats and confirmed that, as a group, old rats display poorer spatial learning and behavioral flexibility than younger adults. Surprisingly, when animals were clustered as good and bad performers, our data revealed that while in younger animals better cognitive performance was associated with longer dendritic trees and increased levels of synaptic markers in the hippocampus and prefrontal cortex, the opposite was found in the older group, in which better performance was associated with shorter dendrites and lower levels of synaptic markers. Additionally, in old, but not young individuals, worse performance correlated with increased levels of BDNF and the autophagy substrate p62, but decreased levels of the autophagy complex protein LC3. In summary, while for younger individuals "bigger is better", "smaller is better" is a more appropriate aphorism for older subjects.Portuguese Foundation for Science and Technology (FCT) with fellowships granted to: Cristina Mota (SFRH/BD/81881/2011), Susana Monteiro (SFRH/BD/69311/2010), Sofia Pereira das Neves and Sara Monteiro-Martins (PIC/IC/83213/2007); and by the European Commission within the 7th framework program, under the grant agreement: Health-F2-2010-259772 (Switchbox). In addition, this work was co-funded by the Northern Portugal Regional Operational Programme (ON.2 SR&TD Integrated Program – NORTE-07-0124-FEDER-000021), through the European Regional Development Fund (FEDER) and by national funds granted by FCT (PEst-C/SAU/LA0026/2013), and FEDER through the COMPETE (FCOMP-01-0124-FEDER-037298)
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