The role of fouling mechanisms in a membrane bioreactor

2007 ◽  
Vol 55 (8-9) ◽  
pp. 455-464 ◽  
Author(s):  
G. Di Bella ◽  
F. Durante ◽  
M. Torregrossa ◽  
G. Viviani ◽  
P. Mercurio ◽  
...  
Keyword(s):  
Hollow Fibre ◽  
Chemical Cleaning ◽  
Deposition Mechanism ◽  
Pore Blocking ◽  
Solids Concentration ◽  
Aeration System ◽  
Start Up ◽  
Cake Layer ◽  
Raw Wastewater

The present study has aimed to quantify the role of pore blocking and cake layer in a laboratory scale hollow fibre membrane module in submerged configuration. The membrane reactor (MBR) was fed with raw wastewater, only screened with a 2-mm sieve, collected from the Palermo WWTP. The MBR was characterised by an operating volume of 190 L and equipped with an aeration system located on the bottom of the reactor. The MBR operated for 65 days. The permeate was extracted by imposing a constant flux through the membrane (21 Lh−1m−2). The results confirm the importance of pore blocking control during start-up. In particular, it provides a rapid irreversible fouling that takes place at the beginning of the filtration process, before the deposition mechanism. Therefore, low suspended solids concentration in the initial phase causes a fast irreversible fouling. This circumstance creates the need for more frequent chemical cleaning after start-up without inoculum. Finally, the results underline that the cake has a mainly reversible feature.

Treatment of winery wastewaters in a membrane submerged bioreactor

2007 ◽  
Vol 56 (2) ◽  
pp. 63-69 ◽  
Author(s):  
P. Artiga ◽  
M. Carballa ◽  
J.M. Garrido ◽  
R. Méndez
Keyword(s):  
Tap Water ◽  
Oxygen Demand ◽  
Biomass Concentration ◽  
Pilot Scale ◽  
White Wine ◽  
Hollow Fibre ◽  
Organic Loading Rate ◽  
Wine Production ◽  
Solids Concentration ◽  
Start Up

Wine production is seasonal, and thus the wastewater flow and its chemical oxygen demand (COD) concentrations greatly vary during the vintage and non-vintage periods, as well as being dependant on the winemaking technologies used, e.g. red, white or special wines production. Due to this seasonal high variability in terms of organic matter load, the use of membrane biological reactors (MBR) could be suitable for the treatment of such wastewaters. MBR offers several benefits, such as rapid start up, good effluent quality, low footprint area, absence of voluminous secondary settler and its operation is not affected by the settling properties of the sludge. A pilot scale hollow fibre MBR system of 220 L was fed by adequately diluting white wine with tap water, simulating wastewaters generated in wineries. The COD in the influent ranged between 1,000 and 4,000 mg/L. In less than 10 days after the start up, the system showed a good COD removal efficiency. The COD elimination percentage was always higher than 97% regardless of the organic loading rate (OLR) applied (0.5–2.2 kg COD/m3 d), with COD concentrations in the effluent ranging between 20 and 100 mg/L. Although the biomass concentration in the reactor increased from 0.5 to 8.6 g VSS/L, the suspended solids concentration in the effluent was negligible. Apparent biomass yield was estimated in 0.14 g VSS/g COD.

Membrane thickening of water works sludge

2001 ◽  
Vol 1 (5-6) ◽  
pp. 215-220
Author(s):  
A. Gillighan ◽  
S.J. Judd ◽  
R. Eyres
Keyword(s):  
Hydraulic Resistance ◽  
Reasonable Agreement ◽  
Chemical Cleaning ◽  
Solids Concentration ◽  
Significant Difference ◽  
Layer Resistance ◽  
Tubular Membranes ◽  
Resistance Data ◽  
Mechanical Cleaning ◽  
Dynamic Layer

The efficacy of ultrafiltration (UF) and microfiltration (MF) membranes was assessed for the concentration of actual waterworks sludges using crossflow tubular membranes operated at constant trans-membrane pressure. The MF membrane gave higher initial fluxes than the UF membrane but after 10 min of filtration the flux value and its decline tended to be very similar for both membranes operating under the same conditions. All membranes gave permeate product water of <0.2 NTU and <100ppb coagulant at all times. For both membranes mechanical cleaning, with sponge balls, was at least as effective as acid chemical cleaning, indicating that no significant permanent internal fouling occurred for these membrane materials. Hydraulic resistance data indicated a significant difference in the dynamic layer resistance between the two membranes. Whilst the UF membrane had a hydraulic resistance 3.7 times that of the MF membrane, the dynamic layer formed on the UF membrane during operation displayed a maximum hydraulic resistance almost nine times lower than that of the MF membrane operating under the same conditions. Correlation of cake resistance R versus feed solids concentration C for all the data generated for t>0 demonstrated reasonable agreement with the expression R∝ca where a=0.37 in the current study. This trend has been recorded in previous reported studies, a varying between 0.33 and 0.62 depending on sludge dewaterability.

The Role of Global Entrepreneurship in Utilizing Retired Workforce and Export Start-Up

2017 ◽  
Vol 21 (2) ◽  
pp. 23-44
Author(s):  
Kyungil Khoe ◽  
Hyuk-Jin Ko ◽  
Yeonsung Cho ◽  
Seon-U Kim
Keyword(s):  
Start Up ◽  
Global Entrepreneurship

scholarly journals Innovation Capabilities and the Performance of Start-Ups in Korea: The Role of Government Support Policies

2021 ◽  
Vol 13 (11) ◽  
pp. 6009
Author(s):  
Se-Kyoung Choi ◽  
Sangyun Han ◽  
Kyu-Tae Kwak
Keyword(s):  
Firm Performance ◽  
Financial Support ◽  
Political Support ◽  
Sustainable Growth ◽  
Government Support ◽  
Role Of Government ◽  
Positive Effects ◽  
Start Up ◽  
Start Ups

What kind of capacity is needed to improve the performance of start-ups? How effective are government support policies in improving start-up performance? Start-ups are critical firm group for ensuring the prospective and sustainable growth of an economy, and thus many countries’ governments have established support policies and they are likely to engage more widely in forward-looking political support activities to ensure further growth and expansion. In this paper, the effect of innovation capabilities and government support policies on start-up performance is examined. We used an unbalanced panel data analysis with a random effect generalized least squares. We investigated the effect of government support policies on 4368 Korean start-ups. The findings indicated that technology and knowledge capabilities had positive effects on the sales performance of start-ups, and government financial support positively affected the relationship between knowledge capability and firm performance. However, when government financial support increased, marketing capability was negatively associated with firm performance. These results demonstrate the significant role of government financial support, including its crowding in but also its crowding out effect. Practical implications: To be more effective, governments should employ innovation-driven entrepreneurship policy approaches to support start-ups. To improve their performance, start-ups need to increase their technology and knowledge capabilities. This study extends recent efforts to understand more fully the effect of government support policies on start-ups differing in their technology, knowledge, and marketing capabilities.

scholarly journals Universities and start-up creation by Ph.D. graduates: the role of scientific and social capital of academic laboratories

2021 ◽  
Author(s):  
Alessandro Muscio ◽  
Sotaro Shibayama ◽  
Laura Ramaciotti
Keyword(s):  
Social Capital ◽  
Training Period ◽  
Scientific Excellence ◽  
Academic Knowledge ◽  
Start Up ◽  
Industry Collaboration ◽  
Business Experience ◽  
Subject Areas ◽  
Scientific Capital

AbstractThis paper investigates how the characteristics of university laboratories influence the propensity of Ph.D. students to entrepreneurship, and thus, contribute to the transfer of academic knowledge to society. As determinants of Ph.D. entrepreneurship, we focus on the lab scientific and social capital as well as on the business experience that Ph.D. students acquire during their training period. The empirical exercise is based on questionnaire survey data of 5266 Ph.D. students in Italian universities in all subject areas. First, we find that 6.7% of the Ph.D. graduates engage in startup activities, and thus, Ph.D. training seems to contribute to knowledge transfer through entrepreneurship. Second, Ph.D. entrepreneurship is driven by business experience, in the forms of industry collaboration and industrially applicable research projects, during their training period. Third, the lab scientific capital is negatively associated with Ph.D. entrepreneurship, suggesting a conflict between scientific excellence and entrepreneurship, but this effect is mitigated if students acquire business experience. Fourth, the lab social capital increases the chance of startup when students have business experience. We further investigate the effects of lab environment by distinguishing between startups that are based on university research and startups that are not, finding different determinants.

The link between interpersonal and interorganisational networking: the role of start-up members' achievement-related affect

2021 ◽  
Vol 13 (1) ◽  
pp. 63
Author(s):  
Maria Beatriz Esperança ◽  
Aristides I. Ferreira ◽  
Catarina Correia Leal ◽  
Timo Braun
Keyword(s):  
Start Up

scholarly journals The Role of Marketing Research for Entrepreneurship

2007 ◽  
Vol 6 (2) ◽  
pp. 25-37
Author(s):  
Jyotirmoy Ghosh ◽  
G Anjaneyaswamy
Keyword(s):  
Life Cycle ◽  
Market Research ◽  
Planning Process ◽  
Marketing Research ◽  
New Product ◽  
Entrepreneurial Marketing ◽  
Actual Experience ◽  
Marketing Decision ◽  
Start Up

Marketing research is defined as "the systematic and objective process of gathering, recording, and analyzing data for aid in making marketing decision." The essence of marketing research is to provide information used in decision making, and for the entrepreneur; there are fundamental differences between market information needed prior to start up and after a firm is established. Prior to opening for business, the entrepreneur wants to know whether a market exist for a new product or service, who is likely to be a primary customer, how to position the enterprise in a market, and how the product or service will be priced, promoted and distributed. Addressing these issues become part of the pre start up planning process. Once a firm has become established, much of this information is authenticated through actual experience, and market research expands to include a continuous competitive analysis.An effort has been made to demonstrate the above mentioned characteristics of marketing research undertaken by the entrepreneurs. The first half of the article portrays an effective framework of the methodology for marketing research. Entrepreneurial marketing research differs from its normal counterpart. These exclusive features are expressed and discussed in details. In the second part of the article, an effort has been made to narrate the nature of marketing research that can be ideally applied to all the different stages of successful venture life cycle. The functioning of all the different stage of the life cycle are discussed with the corresponding marketing research techniques that can be ideally applied, being expressed.

scholarly journals Role of technopreneurs in indain context

2019 ◽  
Vol 9 (4) ◽  
pp. 249-252
Author(s):  
ARUNKUMAR B ◽  
GURUNATHAN A
Keyword(s):  
Developed Countries ◽  
Achievement Level ◽  
Indian Government ◽  
Indian Context ◽  
Start Up ◽  
Long Time ◽  
Technology Parks ◽  
Current Scenario ◽  
The Developed Countries

Start-up is a basic thing that a person trying to do something real and new, it has high rates of failure, but the minority of successes includes companies that have evolved as giant and market setters. People who use technology for being entrepreneurs are called as technopreneurs, being born the risk in business in addition to being accomplished the achievement level in innovative and initiative a new kind of product and service to the community. India is enjoying with the fruitful result on the progress of start-up environment which it has been focusing for a long time, the best time for promoting the techno start-up to be apillar of strength in the forthcoming trends. The boom of technopreneurs of our nation had been targeted by the developed countries since 2010. A new benchmark may be set in heavily offering number of opportunities to extent the business, which is also a next level of the start-up environmentin the current scenario and the efforts are taken by the Indian Government. The Technopreneurship's growth and contribution to the start-up technopreneurs in Indian context are catered in this paper and in addition new schemes and well equipped technology parks will be effectuated for the goodness of the new start-up.

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