Relations between carbon removal rates, biofilm size and density of a novel anaerobic reactor: the inverse turbulent bed

2000 ◽  
Vol 41 (4-5) ◽  
pp. 253-260 ◽  
Author(s):  
P. Buffière ◽  
R. Moletta
Keyword(s):  
Removal Rate ◽  
Removal Rates ◽  
Carbon Removal ◽  
Biofilm Growth ◽  
Loading Rates ◽  
Biomass Activity ◽  
High Turbulence ◽  
The One ◽  
High Level ◽  
Very High

An anaerobic inverse turbulent bed, in which the biogas only ensures fluidisation of floating carrier particles, was investigated for carbon removal kinetics and for biofilm growth and detachment. The range of operation of the reactor was kept within 5 and 30 kgCOD· m−3· d−1, with Hydraulic Retention Times between 0.28 and 1 day. The carbon removal efficiency remained between 70 and 85%. Biofilm size were rather low (between 5 and 30 μm) while biofilm density reached very high values (over 80 kgVS· m−3). The biofilm size and density varied with increasing carbon removal rates with opposite trends; as biofilm size increases, its density decreases. On the one hand, biomass activity within the reactor was kept at a high level, (between 0.23 and 0.75 kgTOC· kgVS· d−1, i.e. between 0.6 and 1.85 kgCOD·kgVS · d−1).This result indicates that high turbulence and shear may favour growth of thin, dense and active biofilms. It is thus an interesting tool for biomass control. On the other hand, volatile solid detachment increases quasi linearly with carbon removal rate and the total amount of solid in the reactor levels off at high OLR. This means that detachment could be a limit of the process at higher organic loading rates.

The process of recruitment of immigrants in the construction sector. The cases of Italy and Portugal

2003 ◽  
Vol 9 (3) ◽  
pp. 452-468 ◽  
Author(s):  
Ivana Fellini ◽  
Pedro Góis ◽  
José Carlos Marques
Keyword(s):  
Mediterranean Area ◽  
Foreign Workers ◽  
Construction Sector ◽  
Skilled Workers ◽  
Factors Affecting ◽  
The One ◽  
High Level ◽  
Skills Shortages ◽  
Very High

This article deals with the recruitment and employment of foreign workers in the Italian and Portuguese construction sectors. The two countries show a very similar structure and organisation of the sector. Nevertheless, Italy only ‘imports’ immigrants for the sector whereas Portugal both imports foreign labour and exports construction workers on the European market. On the basis of a comparative analysis of the occupational structure of foreign workers and of interviews with construction employers in the two countries this article examines such differences and discusses how (also with reference to irregular work and the underground economy) and why the construction sector represents a key sector for the economic insertion and adaptation of immigrants in the Mediterranean area. Skills shortages and labour cost issues are highlighted as factors affecting recruitment of foreigners in a sector characterised by a very high level of deregulation and informality, and in which processes of downsizing on the one hand and externalisation on the other have had as an important outcome the nearly exclusive role of subcontracting in the recruitment of semi- and low-skilled workers.

Numerical Investigation of New Design of the Etoile Flow Straightener

2011 ◽  
Author(s):  
Boualem Laribi ◽  
Abdelkader Youcefi ◽  
Djelloul Belkacemi
Keyword(s):  
Velocity Profile ◽  
Numerical Investigation ◽  
Flow Behavior ◽  
Flow Parameters ◽  
Flow Metering ◽  
High Fluid ◽  
High Turbulence ◽  
High Level ◽  
High Degree ◽  
Very High

Flow metering of industrial fluids remains the concern of several researchers and exporting countries of gas and oil in the world. It is in this context that a vast numerical investigation is done in our laboratory of Industrial Fluids Measurements and Applications (FIMA). This article examines numerically a new design of the Etoile flow straightener which is described by the standard ISO 5167. This new design consists in removing the central part of the Etoile which, according to researchers, leads to a very high level of turbulence. Our intervention relates to the development and the establishment of the flow parameters downstream the Etoile with and without central part. The flow is produced by air in a 100mm pipe diameter and 40D of length with a Reynolds number of 2.5×105. The disturbance is a valve maintained 100%, 50% and 30% open. The flow parameters examined are velocity profile, turbulence intensity profile, and the fluid gyration angle. The code CFD Fluent is used for this simulation. The results obtained are compared according to directives of the standard ISO 5167. The results obtained show that for the valve settings 30% and 50% open, upstream the Etoile, we have a high turbulence level and a velocity profile with recirculation zones more significant for the valve 30% open than for the valve 50% open. It is also noted that the valve develop very high fluid gyration angle apart from the standard values. The flow behavior downstream the central part of Etoile described by the ISO 5167 is well simulated with the valve open at 100%, with a deficit of flow and a very high degree of turbulence. At this stage for the two designs, the noticed results seem so identical beyond a certain stations downstream the Etoile.

scholarly journals TRENDS OF AREA, PRODUCTION AND YIELD IN WESTERN UTTAR PRADESH ‘A DISTRICT-WISE ANALYSIS OF FOODGRAINS’

2017 ◽  
Vol 2 (1) ◽  
pp. 26-27
Author(s):  
Dr. Rajeev Sirohi
Keyword(s):  
Growth Process ◽  
Uttar Pradesh ◽  
Special Significance ◽  
Production And Distribution ◽  
Live Stock ◽  
Per Capita ◽  
The One ◽  
High Level ◽  
Agriculture Development ◽  
Very High

The term ‘agriculture’ literally means the science and practices of the cultivation of the soil including the raising of live stock. In economic jargon, the word includes the production and distribution of goods of agriculture origin for consumption by the population at large, domestic or foreign. In this respect it is a complex sector encompassing many products. The understanding of the contribution of agriculture to economy and of their relationship with the growth process of economy is of special significance for setting goals of agriculture development for a region and for designing a strategy for agriculture development.Agricultural development in Western Uttar Pradesh has been characterized by wide disparities. One the one hand there are districts which have experienced a very high level of per capita agricultural output caused by a sustained rise in per hectare agricultural  utput. In view of this it becomes necessary to study the extent of the inequalities in agricultural productivity and to identify the factors underlying this state affairs

Effect of full and partial-bed configuration on carbon removal performance of biological aerated filters

2008 ◽  
Vol 58 (5) ◽  
pp. 977-983 ◽  
Author(s):  
Fatihah Suja ◽  
Tom Donnelly
Keyword(s):  
Comparative Study ◽  
Removal Rate ◽  
Organic Loading ◽  
Carbon Removal ◽  
Loading Rates ◽  
Removal Capacity ◽  
Organic Removal ◽  
Biomass Loss ◽  
The Masses

A comparative study to explore the characteristics of partially and fully packed biological aerated filters (BAFs) in the removal of carbon pollutant, reveals that the partial-bed reactor can perform comparably well with the full-bed reactor. The organic removal rate was 5.34 kg COD m−3 d−1 at Organic Loading Rates (OLR) 5.80±0.31 kg COD m−3 d−1 for the full-bed, and 5.22 kg COD m−3 d−1 at OLR 5.79±0.29 kg COD m−3 d−1 for the partial-bed. In the partial-bed system, where the masses of biomass were only 41–51% of those of the full-bed, the maximum carbon removal limit was still between 5 to 6 kg COD m−3 d−1. At organic loadings above 5.0 kg COD m−3 d−1, the carbon removal capacity in both systems was limited by the mass and activity of microorganisms. The SRT in the full and partial-bed reactors was primarily controlled by the biomass loss in the effluent and during backwash operation. The SRT was reduced from 20.08 days at OLR 4.18±0.20 kg COD m−3 d−1 to 7.62 days at OLR 5.80±0.31 kg COD m−3 d−1 in the full-bed, and from 7.17 days to 4.21 days in the partial-bed. After all, SRT values in the partial-bed were always lower than those in the full-bed.

scholarly journals The Muslim Employment Gap, Human Capital, and Ethno-Religious Penalties: Evidence from Switzerland

2018 ◽  
Vol 6 (2) ◽  
pp. 151-161 ◽  
Author(s):  
Anaïd Lindemann ◽  
Jörg Stolz
Keyword(s):  
Human Capital ◽  
Religious Affiliation ◽  
Contextual Factors ◽  
The Other ◽  
Level Of Education ◽  
Migration Factors ◽  
Employment Gap ◽  
The One ◽  
High Level ◽  
Very High

In Europe, Muslims are more likely to be unemployed than non-Muslims. Many studies try to explain this employment gap by human capital and contextual factors on the one hand, and by ethno-religious penalties (discrimination due to religious affiliation, religiosity, or migration factors) on the other. In these studies, it is normally assumed that human capital mediates the effect of Muslim affiliation, and that controlling for human capital will therefore reduce the odds for Muslims of being unemployed. We replicate the well-known study by Connor and Koenig (2015) along these lines, using the most recent and representative Swiss data from 2014 (N = 16,487). Our key result is that Muslim affiliation does not mediate, but actually moderates, the effect of human capital on unemployment. We find a powerful interaction in that Muslims both with a very low and a very high level of education are disproportionally often unemployed. This is important because it means that raising the human capital of Muslims will not automatically lessen, but may instead actually widen, the employment gap. We discuss possible theoretical mechanisms that might explain this finding.

Treatment of wastewater containing high phenol concentrations using stabilisation ponds enriched with activated sludge

2005 ◽  
Vol 51 (12) ◽  
pp. 257-260 ◽  
Author(s):  
M.S. Ramos ◽  
J.L. Dávila ◽  
F. Esparza ◽  
F. Thalasso ◽  
J. Alba ◽  
...  
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Sole Carbon Source ◽  
Removal Rate ◽  
Phenol Removal ◽  
Removal Rates ◽  
Loading Rates ◽  
Waste Stabilisation Ponds ◽  
Maximum Value ◽  
Removal Efficiencies

Treatment of wastewater containing high phenol concentrations (up to 4,000 mg/l, 1,600 kg/ha.d) in laboratory-scale stabilisation ponds enriched with activated sludge was studied. Phenol was biodegraded efficiently, even when fed as the sole carbon source. At influent concentrations of 1,000, 1,300, 1,600, 1,900, 2,500, 3,000 and 4,000 mg/l of phenol (loading rates of 400, 520, 640, 760, 1,000, 1,200 and 1,600 kg phenol/ha.d), the phenol removal efficiencies were 92, 89, 81, 81, 76, 65 and 22%, respectively. At 4,000 mg/l of phenol, the enriched ponds were significantly inhibited. The maximum phenol removal rate observed was 780 kg/ha.d, which is 7.7 times higher than the maximum value reported for attached-growth waste stabilisation ponds. All along the experiments, the enriched ponds showed removal rates 1.8–20.5 times higher than the values observed in control pond (not enriched). The results suggest that enrichment is an effective method to increase xenobiotic removal rates of stabilisation ponds.

التغير المناخي واثره في المقنن المائي لمحصول العنب في محافظة ديالى

2019 ◽  
Vol 1 (34) ◽  
pp. 391-422
Author(s):  
اشواق حسن حميد صالح
Keyword(s):  
Climate Change ◽  
Statistical Analysis ◽  
Wind Speed ◽  
Extreme Temperature ◽  
Solar Brightness ◽  
The Subject ◽  
Climate Station ◽  
The Times ◽  
High Level ◽  
Very High

Climate change and its impact on water resources is the problem of the times. Therefore, this study is concerned with the subject of climate change and its impact on the water ration of the grape harvest in Diyala Governorate. The study was based on the data of the Khanaqin climate station for the period 1973-2017, (1986-2017) due to lack of data at governorate level. The general trend of the elements of the climate and its effect on the water formula was extracted. The equation of change was extracted for the duration of the study. The statistical analysis was also used between the elements of the climate (actual brightness, normal temperature, micro and maximum degrees Celsius, wind speed m / s, relative humidity% The results of the statistical analysis confirm that the water ration for the study area is based mainly on the X7 evaporation / netting variable, which is affected by a set of independent variables X1 Solar Brightness X4 X5 Extreme Temperature Wind Speed ​​3X Minimal Temperature and Very High Level .

Comparative study of domestic wastewater treatment efficiencies between facultative pond and water spinach pond

1995 ◽  
Vol 32 (3) ◽  
pp. 263-270 ◽  
Author(s):  
Seni Karnchanawong ◽  
Jaras Sanjitt
Keyword(s):  
Growth Rates ◽  
Domestic Wastewater ◽  
Pilot Scale ◽  
Organic Content ◽  
Water Spinach ◽  
Removal Rates ◽  
Mass Removal ◽  
Loading Rates ◽  
Tropical Conditions ◽  
Average Water

Two pilot-scale studies were comparatively conducted under tropical conditions during December 1992 to September 1993. One study involved facultative ponds(FP) and the others water spinach ponds(SP). Four rectangular concrete ponds, 0.8 m × 2.4 m × 1.1 m (width × length × depth), were employed to treat the Chiang Mai University campus wastewater. Water spinach (Ipomoea aquatica) was planted in two of the ponds. The influent characteristics noted showed a low organic content, i.e. BOD 25.4-29.9 mg/l, with BOD:N ratio around 1:1. The investigations were conducted using the following hydraulic retention times (HRT): 1.6, 2, 2.7, 4, 8 and 16 d. The results showed that the BOD, COD and SS mass removal rates increased as the mass loading rates increased and the SP was significantly more effective in reducing the organic content than the FP. No relationship was found between TN mass removal and the loading rates. However, the TP mass removal rates in the SP and the FP were rather low and were considered to be insignificant. It was observed that SS accumulated in the water spinach root systems which tended to act as a strainer. This process led to plant growth inhibition and finally die-off. The average water spinach growth rates varied from 37 to 107 g wet wt./(m2.d) and no relationship was established between the growth rates and the HRT.

Analysis of organic removal rates in the aerated submerged fixed film process

1998 ◽  
Vol 38 (8-9) ◽  
pp. 213-221 ◽  
Author(s):  
Mohamed F. Hamoda ◽  
Ibrahim A. Al-Ghusain
Keyword(s):  
Pilot Plant ◽  
Removal Rate ◽  
Domestic Wastewater ◽  
Removal Rates ◽  
Hydraulic Loading ◽  
Organic Removal ◽  
Wide Range ◽  
Fixed Film ◽  
Cod Removal Rate ◽  
And Performance

Performance data from a pilot-plant employing the four-stage aerated submerged fixed film (ASFF) process treating domestic wastewater were analyzed to examine the organic removal rates. The process has shown high BOD removal efficiencies (> 90%) over a wide range of hydraulic loading rates (0.04 to 0.68 m3/m2·d). It could also cope with high hydraulic and organic loadings with minimal loss in efficiency due to the large amount of immobilized biomass attained. The organic (BOD and COD) removal rate was influenced by the hydraulic loadings applied, but organic removal rates of up to 104 kg BOD/ m2·d were obtained at a hydraulic loading rate of 0.68 m3/m2·d. A Semi-empirical model for the bio-oxidation of organics in the ASFF process has been formulated and rate constants were calculated based on statistical analysis of pilot-plant data. The relationships obtained are very useful for analyzing the design and performance of the ASFF process and a variety of attached growth processes.

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