- J.A. Egea (1)
- Jingyi Han (1)
- Y.L. Lu (1)
- W. Luo (1)
- A.H. Paulitsch-Fuchs (1)
- J. Racyte (1)
- H.H.M. Rijnaarts (1)
- Jim Ruijven van (1)
- Y.J. Shi (1)
- Y.M. Sun (1)
- D. Vries (1)
- T.Y. Wang (1)
- G. Wang (1)
- D.R. Yntema (1)
Alternating electric fields combined with activated carbon for disinfection of Gram negative and Gram positive bacteria in fluidized bed electrode system
Racyte, J. ; Bernard, S. ; Paulitsch-Fuchs, A.H. ; Yntema, D.R. ; Bruning, H. ; Rijnaarts, H.H.M. - \ 2013
Water Research 47 (2013)16. - ISSN 0043-1354 - p. 6395 - 6405.
water treatment plants - urban waste-water - antibiotic-resistance - antimicrobial activity - escherichia-coli - inactivation - particles - cells - flow - viability
Strong electric fields for disinfection of wastewaters have been employed already for several decades. An innovative approach combining low strength (7 V/cm) alternating electric fields with a granular activated carbon fluidized bed electrode (FBE) for disinfection was presented recently. For disinfection performance of FBE several pure microbial cultures were tested: Bacillus subtilis, Bacillus subtilis subsp. subtilis, Enterococcus faecalis as representatives from Gram positive bacteria and Erwinia carotovora, Pseudomonas luteola, Pseudomonas fluorescens and Escherichia coli YMc10 as representatives from Gram negative bacteria. The alternating electric field amplitude and shape were kept constant. Only the effect of alternating electric field frequency on disinfection performance was investigated. From the bacteria tested, the Gram negative strains were more susceptible and the Gram positive microorganisms were more resistant to FBE disinfection. The collected data indicate that the efficiency of disinfection is frequency and strain dependent. During 6 h of disinfection, the decrease above 2 Log units was achieved with P. luteola and E. coli at 10 kHz and at dual frequency shift keying (FSK) modulated signal with frequencies of 10 kHz and 140 kHz. FBE technology appears to offer a new way for selective bacterial disinfection, however further optimizations are needed on treatment duration, and energy input, to improve effectiveness.
Juiste combinatie maakt honderd procent reiniging mogelijk : vier zuiveringsmethoden getest
Beerling, Ellen ; Ruijven, Jim van - \ 2013
greenhouse horticulture - pesticides - emission - disposal - water treatment - waste water treatment - surface water - water treatment plants - agricultural research
Hexachlorobenzene sources, levels and human exposure in the environment of China
Wang, G. ; Lu, Y.L. ; Han, Jingyi ; Luo, W. ; Shi, Y.J. ; Wang, T.Y. ; Sun, Y.M. - \ 2010
Environment International 36 (2010)1. - ISSN 0160-4120 - p. 122 - 130.
persistent organic pollutants - polybrominated diphenyl ethers - human breast-milk - polychlorinated biphenyl residues - organochlorine pesticides ocps - water treatment plants - pearl river delta - taihu lake region - temporal trends - asian countries
This article summarizes the published scientific data on sources, levels and human exposure of hexachlorobenzene (HCB) in China. Potential sources of unintended HCB emission were assessed by production information, emission factors and environmental policies. HCB was observed in various environmental compartments in China. HCB levels increased from South China to North China in most of environmental compartments (air, soil and mussel). Some hotspots were identified near the factories producing and using HCB. In terms of spatial distribution, HCB concentrations in air and shellfish showed much variation, which indicated some primary emission sources in China. HCB levels in air and human milk in China were relatively higher than those in other countries, but HCB levels in other compartments were similar to those in Europe and other countries in Eastern Asia. In the limited studies on temporal trends of HCB levels in China, HCB concentrations in air, sediment, fish and human milk did not show a consistent downward trend. Although HCB levels in food and human milk does not pose a health risk in China at present, long-term exposure to HCB should not be overlooked.
Global optimization for integrated design and control of computationally expensive process models
Egea, J.A. ; Vries, D. ; Alonso, A.A. ; Banga, J.R. - \ 2007
Industrial & Engineering Chemistry Research 46 (2007)26. - ISSN 0888-5885 - p. 9148 - 9157.
water treatment plants - control strategies - simulation - denitrification - nitrification
The problem of integrated design and control optimization of process plants is discussed in this paper. We consider it as a nonlinear programming problem subject to differential-algebraic constraints. This class of problems is frequently multimodal and "costly" (i.e., computationally expensive to evaluate). Thus, on the one hand, local optimization techniques usually fail to locate the global solution, and, on the second hand, most global optimization methods require many simulations of the model, resulting in unaffordable computation times. As an alternative, one may consider global optimization methods which employ surrogate-based approaches to reduce computation times and which require no knowledge of the underlying problem structure. A challenging wastewater treatment plant (WWTP) benchmark model1 is used here to evaluate the performance of these techniques. Numerical experiments with different optimization solvers indicate that the proposed benchmark optimization problem is indeed multimodal, and that via global optimization we can achieve an improvement of the controllers' performance compared to the best tuned controllers' settings available in the literature. Moreover, these results show that surrogate-based methods may reduce computation times while ensuring convergence to the best known solutions. --------------------------------------------------------------------------------