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

Eikelboom, DH; Andreadakis, A; Andreasen, K

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