Survey of filamentous populations in nutrient removal plants in four European countries

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dc.contributor.author Eikelboom, DH en
dc.contributor.author Andreadakis, A en
dc.contributor.author Andreasen, K en
dc.date.accessioned 2014-03-01T02:41:34Z
dc.date.available 2014-03-01T02:41:34Z
dc.date.issued 1998 en
dc.identifier.issn 0273-1223 en
dc.identifier.uri https://dspace.lib.ntua.gr/xmlui/handle/123456789/30532
dc.subject Filamentous bacteria en
dc.subject Microbial population en
dc.subject Nutrient removal en
dc.subject.classification Engineering, Environmental en
dc.subject.classification Environmental Sciences en
dc.subject.classification Water Resources en
dc.subject.other Bacteria en
dc.subject.other Denitrification en
dc.subject.other Flocculation en
dc.subject.other Growth kinetics en
dc.subject.other Sewage treatment plants en
dc.subject.other Bacterial populations en
dc.subject.other Bulking en
dc.subject.other Filamentous bacteria en
dc.subject.other Nutrient removal en
dc.subject.other Activated sludge process en
dc.subject.other activated sludge en
dc.subject.other nutrient en
dc.subject.other removal en
dc.subject.other waste water en
dc.subject.other activated sludge en
dc.subject.other bacterium en
dc.subject.other biomass en
dc.subject.other conference paper en
dc.subject.other denitrification en
dc.subject.other denmark en
dc.subject.other germany en
dc.subject.other greece en
dc.subject.other netherlands en
dc.subject.other nutrient en
dc.title Survey of filamentous populations in nutrient removal plants in four European countries en
heal.type conferenceItem en
heal.identifier.primary 10.1016/S0273-1223(98)00120-6 en
heal.identifier.secondary http://dx.doi.org/10.1016/S0273-1223(98)00120-6 en
heal.language English en
heal.publicationDate 1998 en
heal.abstract A joint EU research project aimed at solving activated sludge bulking in nutrient removal plants was initiated in 1993. The project started with a survey of the size and composition of the filamentous population in nutrient removal plants in Denmark, Germany, Greece and the Netherlands. The results show that biological nutrient removal process conditions indeed favour filamentous micro-organisms in their competition with floc forming organisms. An increase in the size of the filamentous population resulted in a deterioration of the settling properties of the biomass, except for plants with Bio-P removal conditions. It is assumed that in the latter case the dense clusters of Bio-P bacteria increase the weight of the flocs, and compensate for the effect of the larger number of filaments. Although exceptions frequently occur, the following sequence in decreasing filamentous organism population size was observed for the process conditions indicated: completely mixed + simultaneous denitrification; completely mixed + intermittent aeration/denitrification; alternating anoxic/oxic process conditions, with an anaerobic tank for biological phosphate removal (Bio-Denipho); alternating anoxic/oxic process conditions (Bio-Denitro); predenitrification. The surveys provided little information about the effect of nutrient removal in plants with plug flow aeration basins. Simultaneous precipitation with aluminium salts nearly always resulted in a low number of filaments and a good settling sludge. The size of the filamentous organism population showed a seasonal pattern with a maximum in winter/early spring and a minimum during summer (in Greece: during autumn). This seasonal variation is primarily caused by the effect of the season on the population sizes of M. parvicella, N. limicola and Type 0092. M. parvicella is by far the most important filamentous species in nutrient removal plants. In Denmark only, Type 0041 also frequently dominates the filamentous population, but seldom causes severe bulking. Considering their frequency of occurrence, approx. 10 other filamentous micro-organisms are of minor importance. Growth of some of these species, viz. those which use soluble substrate, can be prevented by the introduction of Bio-P process conditions. M. parvicella and Type 0041 (and probably also Actinomycetes and the Types 1851 and 0092) seem to compete for the same substrates i.e. the influent particulate fraction. Most of the differences in composition of the filamentous microorganism population can be explained by whether or not premixing of influent and recycled sludge is used. In general, premixing for a short period of time followed by anoxic conditions favours Type 0041. M. parvicella seems to proliferate if the particulate fraction is first hydrolysed or if it enters the plant via an oxic zone. It is concluded that bulking in nutrient removal plants is mainly caused by filamentous species requiring the particulate fraction for their growth.A survey of the size and composition of the filamentous populations in nutrient removal plants in Denmark, Germany, Greece and the Netherlands is presented. It is shown that biological nutrient removal conditions favour filamentous microorganisms in their competition with floc-forming bacteria. It is concluded that bulking phenomenon in nutrient removal plants is mainly due to the filamentous species (M. parvicella, N. limicola) requiring the presence of particulate fraction for their growth. en
heal.publisher Elsevier Sci Ltd, Exeter, United Kingdom en
heal.journalName Water Science and Technology en
dc.identifier.doi 10.1016/S0273-1223(98)00120-6 en
dc.identifier.isi ISI:000073933300046 en
dc.identifier.volume 37 en
dc.identifier.issue 4-5 en
dc.identifier.spage 281 en
dc.identifier.epage 289 en

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