Journal ArticleDOI
Anaerobic digestion and wastewater treatment systems
TLDR
It can be shown that there does not exist any need for ‘phase separation’ when treating non- or slightly acidified wastewaters and it looks necessary to reconsider theories for mass transfer in immobilized anaerobic biomass.Abstract:
Upflow Anaerobic Sludge Bed (UASB) wastewater (pre-)treatment systems represent a proven sustainable technology for a wide range of very different industrial effluents, including those containing toxic/inhibitory compounds. The process is also feasible for treatment of domestic wastewater with temperatures as low as 14-16 degrees C and likely even lower. Compared to conventional aerobic treatment systems the anaerobic treatment process merely offers advantages. This especially is true for the rate of start-up. The available insight in anaerobic sludge immobilization (i.e. granulation) and growth of granular anaerobic sludge in many respects suffices for practice. In anaerobic treatment the immobilization of balanced microbial communities is essential, because the concentration of intermediates then can be kept sufficiently low. So far ignored factors like the death and decay rate of organisms are of eminent importance for the quality of immobilized anaerobic sludge. Taking these factors into account, it can be shown that there does not exist any need for 'phase separation' when treating non- or slightly acidified wastewaters. Phase separation even is detrimental in case the acidogenic organisms are not removed from the effluent of the acidogenic reactor, because they deteriorate the settleability of granular sludge and also negatively affect the formation and growth of granular sludge. The growing insight in the role of factors like nutrients and trace elements, the effect of metabolic intermediates and end products opens excellent prospects for process control, e.g. for the anaerobic treatment of wastewaters containing mainly methanol. Anaerobic wastewater treatment can also profitably be applied in the thermophilic and psychrophilic temperature range. Moreover, thermophilic anaerobic sludge can be used under mesophilic conditions. The Expanded Granular Sludge Bed (EGSB) system particularly offers big practical potentials, e.g. for very low strength wastewaters (COD << 1 g/l) and at temperatures as low as 10 degrees C. In EGSB-systems virtually all the retained sludge is employed, while compared to UASB-systems also a substantially bigger fraction of the immobilized organisms (inside the granules) participates in the process, because an extraordinary high substrate affinity prevails in these systems. It looks necessary to reconsider theories for mass transfer in immobilized anaerobic biomass. Instead of phasing the digestion process, staging of the anaerobic reactors should be applied. In this way mixing up of the sludge can be significantly reduced and a plug flow is promoted. A staged process will provide a higher treatment efficiency and a higher process stability. This especially applies for thermophilic systems.read more
Citations
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Journal ArticleDOI
Conversion of wastes into bioelectricity and chemicals by using microbial electrochemical technologies.
Bruce E. Logan,Korneel Rabaey +1 more
TL;DR: In this paper, the key advances that will enable the use of exoelectrogenic microorganisms to generate biofuels, hydrogen gas, methane, and other valuable inorganic and organic chemicals are reviewed.
Journal ArticleDOI
Review paper on current technologies for decolourisation of textile wastewaters: Perspectives for anaerobic biotechnology
TL;DR: This paper provides a critical review on the current technologies available for decolourisation of textile wastewaters and it suggests effective and economically attractive alternatives.
Journal ArticleDOI
Bacterial community structures are unique and resilient in full-scale bioenergy systems
Jeffrey J. Werner,Dan Knights,Dan Knights,Marcelo Loureiro Garcia,Nicholas B. Scalfone,Samual Smith,Kevin E. Yarasheski,Theresa A. Cummings,Allen R. Beers,Rob Knight,Largus T. Angenent +10 more
TL;DR: Investigating the relationships of bacterial community structure with function and environment in a yearlong monthly time series of nine full-scale bioreactor facilities treating brewery wastewater found stronger relationships between community structure and its function rather than its environment.
Journal ArticleDOI
A review: the anaerobic treatment of sewage in uasb and egsb reactors
TL;DR: In this paper, the main characteristics of anaerobic sewage treatment are summarized, with special emphasis on the upflow anaerobically sludge blanket (UASB) reactor, with examples from Europe, Asia and the Americas.
Journal ArticleDOI
Methanogenesis facilitated by electric syntrophy via (semi)conductive iron-oxide minerals
TL;DR: It is suggested that Geobacter grew under syntrophic association with methanogens, and IET could occur via electric currents through (semi)conductive iron-oxide minerals (termed 'electric syntrophy') given the ubiquity of conductive minerals in nature.
References
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Journal ArticleDOI
Energy conservation in chemotrophic anaerobic bacteria.
TL;DR: This article corrects the article on p. 100 in vol.
Journal ArticleDOI
Use of the upflow sludge blanket (USB) reactor concept for biological wastewater treatment, especially for anaerobic treatment
TL;DR: In this paper, the main results obtained with the process in the laboratory as well as in 6 m3 pilot plant and 200 m3 full-scale experiments are presented and evaluated in this paper.
Journal ArticleDOI
UASB process design for various types of wastewaters
Gatze Lettinga,L.W. Hulshoff Pol +1 more
TL;DR: In this article, the design of UASB-reactors is discussed for different types of wastewater, viz. industrial soluble non-complex wastewaters, SS-rich complex wastewwaters and domestic sewage.
Journal ArticleDOI
Kinetics of Anaerobic Treatment
TL;DR: It is concluded that with but few exceptions, the evidence for the significance of mass transfer effects in the different reactor configurations is circumstantial and, in some cases, contradictory.
Journal ArticleDOI
Mechanism of inhibition caused by long‐chain fatty acids in anaerobic digestion process
TL;DR: The inhibitory effect of long‐chain fatty acids on the anaerobic digestion process was examined in batch experiments using synthetic substrates and neutral fat in the whole milk was easily hydrolyzed to long‐ chain fatty acids, which brought about the inhibition.