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1

The synthesis of polyhydroxyalkanoates by activated sludge

100%
Klimiuk E., Pokoj T.
Biotechnologia
|
2008
|
issue 3
9-27
EN
Polyhydroxyalkanoates are polyesters insoluble in water, synthesized by microorganisms and accumulated intracellular as storage materials. They are marked by high degree of polimerization, non-toxicity, wide range of application and biodegrability. Until now, there have been applied mainly pure microbial cultures for industrial PHAs production. Currently, for that purpose there are conducted intensive investigations on use of mixed microbial cultures (activated sludge). The microorganisms of activated sludge accumulate polyhydroxyalkanoates as storage materials when availability of organics as electron donors and oxygen or nitrate (electron acceptors) is distributed in time and space or when the sludge is submitted to consecutive periods of external substrate accessibility and unavailability. The process efficiency depends on feed composition and reactor operating conditions. Nowadays, there are two types of reactor operational strategies. In municipal wastewater treatment plants, a two-stage process is used: 1 ? selection of excess sludge to specific type of substrate (molesses, whey) in SBR, and 2 ? PHAs production in batch reactor. In wastewater treatment plants from agricultural and food industry, acidogenic fermentation is introduced as an additional stage, where the organic wastes are converted into a mixture of organic acids, and then used as a substrate for PHAs storage.
2

Accumulation of polyhydroxyalkanoates (PHAs) in activated sludge under nitrogen limitation conditions. Part I. Effect of operational condition on effectiveness of poly(3-hydroxybutyric acid) (P(3HB)) accumulation

80%
Pokoj T., Klimiuk E., Kuczajowska-Zadrozna M.
Biotechnologia
|
2005
|
issue 4
197-213
EN
The accumulation of poly(3-hydroxybutyric acid) in activated sludge was investigated. Fed-batch culture was carried out using sodium acetate as the source of carbon. A lack of nitrogen was a stimulating factor of accumulation P(3HB). Two experimental series were run. In series 1, nitrogen was fed into abacterial culture once for the first 24 hours, in series 2 ? for 6 hours each day of the experiment. The effect of operational conditions was evaluated based on the accumulation of P(3HB) in biomass, specific growth rate of microorganisms (m) yield coefficients (YP(3HB)/C, YP(3HB)/X), and productivity P(3HB). It was proved that the degree of accumulation of P(3HB) in activated sludge was comparable in both series. The highest P(3HB) yield of 0.59 g P(3HB)/g COD was attained in series 1 at the 12 th our after ceasing the nitrogen feeding. In series 1, between the 36 th and 48 th hour, the productivity reached the level of about 34 mg P(3HB)/l?h). In series 2, YP(3HB)/C and the productivity accounted for 0.21 g P(3HB)/g ChZT and 21.58 mg P(3HB)/l?h, respectively. The limiting factor of P(3HB) productivity was low specific growth rate of microorganisms of activated sludge. The maximum specific growth (max) reached 0.03 h-1 in series 1 and 0.022h-1 in series 2.
3

Accumulation of polyhydroxyalkanoates (PHAs) in activated sludge under nitrogen limitation conditions. Part II. Estimation of bacterial diversity in activated sludge and analysis of a type of accumulated polyhydroxyalkanoates

80%
Klimiuk E., Ciesielski S., Pokoj T., Rogowski J.
Biotechnologia
|
2005
|
issue 4
214-226
EN
Community diversity of the activated sludge and the type of accumulated PHAs were investigated in this study. Fed-batch culture was carried out using medium culture containing sodium acetate as a carbon source. A factor triggering PHAs synthesis was a lack of nitrogen. The medium culture containing ammonium was periodically fed into bacterial culture for 6 hours each day of the experiment. Genetic analysis of the bacterial community was performed using 16S and 23S rRNA Intergeneric Spacer Region. The obtained results showed that the dominant belonged to the Betaproteobacteria class. In this study, the Time of flight - Secondary Ion Mass Spectrometry was used. This method revealed that the cells of the microorganisms contained mainly monomer units of 3-hydroxybutryric acid. The content of P(3HB) in dry weight accounted for 51% between 72nd and 120th hour of the experiment.
4

Preparation of activated sludge flocs to study their internal structure

80%
Barbusinski K., Koscielak H.
Biotechnologia
|
1997
|
issue 1
37-44
EN
A procedure for the preperation of activated sludge flocs to study their internal structure was presented.
5

Intracellular phosphorus accumulation by bacteria from the population of activated sludge

80%
Czerska B., Miksch K., Korstee G. J. J., Surmacz-Gorska J.
Biotechnologia
|
1997
|
issue 1
59-69
EN
Two strains of bacteria isolated from activated sludge were tested for their ability to grow under aerobic, anaerobic and denitrifying condition.The microorganisms stored phosphorus intracellulary as polyphosphates in aerobic and anoxic mileu.Both strains appared to be able to release phosphates anaerobicaly, which was stimulated by acetate.Particularly high P-relaese effect was observed in the case of bacteria which grew under anoxic conditions.
6

Phosphorus removal in the activated sludge process

80%
Barbusinski K.
Biotechnologia
|
1995
|
issue 2
153-163
EN
The machnism of biological phosphorus removal in activated sludge is not fully understood.On the other hand, the enhanced biological P-removal techniques are satisfactorily used in many full-scale wastewater treatment plants.In the paper, factors which influence the effectiveness of biological phosphorus reduction are discussed.
7

Cooxidation of some nonionic surfactans

80%
Janosz-Rajczyk M., Grabinska-Sota E., Litwin E.
Biotechnologia
|
1997
|
issue 1
117-130
EN
Biodegradation was carried out in the laboratory continous-flow activated sludge system and the river water test.In the river water tests, the source of carbon and energy for the microorganisms was nonionic surfactant or nonionic surfactant and glucose.The river ware tests were conducted with and without plants as Cryptocoryne.it has been found that the nonionic surfactant with chain branching was readily biodegradable in the cooxidation process by the microorganisms of activated sludge and microorganisms from the river water test.
8

Optimization of activated sludge storage before RNA isolation

80%
Cydzik-Kwiatkowska A., Wnuk M.
Biotechnologia
|
2011
|
issue 1
101-105
EN
Proper sample storage before RNA isolation is crucial for a reliable assessment of microbial activity in activated sludge. In our studies, different amounts of activated sludge expressed in mg of total suspended solids (TSS) were fixed with a constant volume of RNA later RNA Stabilization Reagent (QIAGEN, Germantown, MD, USA) and stored for 3 or 6 months. The results obtained point out that for the best RNA recovery, 1 mg of activated sludge TSS should be fixed with 33 ?l of the RNAlater. It was also observed that a longer storage period (6 vs. 3 months) of the activated sludge in RNA later lowered RNA recovery by, on average, 25 ? 15% although bacterial diversity in all samples remained unaltered.
9

Nitrogen removal from wastewater with high ammonia nitrogen comcentration via shorter nitrification and denitrification

80%
Surmacz-Gorska J., Cichon A., Miksch A.
Biotechnologia
|
1997
|
issue 1
52-58
EN
Research carried out confirmed the possibility removal by means of shorter nitrification and denitrification in high ammonia concentration wastewater.During nitrification ammonia nitrogen was oxidized to nitrite nitrogen and further oxidation to nitrate nitrogen was stopped.Build-up of nitrite nitrogen was reduced to free nitrogen during denitrification process where reduction of nitrate nitrogen to nitrite nitrogen was avoided.
10

The dynamics of biological reduction of phosphorus and nitrogen compounds in the UCT model system

70%
Czerska B., Miksch K., Surmacz-Gorska J., Debkowska Z.
Biotechnologia
|
1993
|
issue 3
108-115
EN
Investigations on dynamics of and reduction in the system were conducted. After three-week adaptation period, population of activated sludge microorganisms indicated capacity for excessive phosphorus uptake. Source of carbon in synthetic nutrient medium was then sodium acetate (0,5g/l), the concentration of PO4 - 30 mg/l and the NH4 concentration - 60mg/l. At the second stage of the studies the PO3/4 concentration was 15 mg/l in inflow., with increased up to 40 mg/l under anaerobic conditions and decreased to 0,5-1,5 mg/l under aerobic conditions. Togrether wiyth conversions of phosphorus compounds, nitrification processes occurred under aerobioc conditions (12,10-23,15 mg/l) and dentrification in an anoxic reactor (0,1 - 9,5 mg/l). Intensity of the phosphorus and nirogen conversions depended upon biomass loading, degree of recirulation and retention times in the reactors.
11

The influence of aeration intensity on biocenosis and activated sludge function

61%
Hul M., Drzewicki A.
Biotechnologia
|
2001
|
issue 4
189-201
EN
The research was carried out in a conventional sewage treatment plant equipped with completely mixed reactors, located in Olsztyn. The main problem was that it was impossible to simultaneously achieve high treatment efficiency and appropriate sedimentation of the activated sludge. The observations were made at different levels of aeration intensity, controlled by the depth of the mechanical surface aerator submersion. The study confirmed a positive effect of the intensive aeration on the process efficiency and the structure of microfauna and a negative effect on the sedimentation of the activated sludge. The increase of the dissolved oxygen concentration from 1-2 mg?? dm-3 to 3,0-3,3 mg?? dm-3 was accompanied by a 10% growth of COD reduction (from 72-75% to 80-89%), 2-fold increase of ciliates species diversity (from 4-7 to 8-12 taxa), including predators, and the rise of the SVI value from 73 to 441 ml?? g-1. It was recorded that a higher aeration rate results in the flocs lightness, as a consequence of air saturation, and the development of filamentous microorganisms, mainly Microthrix parvicella and Type 1851. The double mechanism of sedimentation disturbances was indicated by the decline of the SVI value to about 200 ml?? g-1 recorded after emerging of aerators irrespective of the same number of filaments. Foam was thought to be the primary proliferation area of low F:M filamentous microorganisms and it appeared as a result of excessive turbidity in the reactors. Foam contained a large amount of M. parvicella and Type 1851. Foam removal by means of water stream at the initial stage of its formation seems to be the most effective method to prevent the bulking of the activated sludge.
12

Application of advanced measuring techniques for study of activated sludge flocs characteristic

51%
Barbusinski K., Klos M.
Biotechnologia
|
1997
|
issue 3
51-61
EN
The activated sludge process is one of the major biological wastewater treatment techniques. The physical properties of the activated sludge flocs are interesting for numerous practical reasons, including activated sludge mass transfer phenomena, biomass flocculation, solid-liquid separation, sludge thickening and dewatering. Application of the advanced measuring techniques, such as image analysis system, and development of specific experimental methods including sample preparation (embedding procedures and microtome sectioning) as well as multi-exposure photography with stroboscope illumination source, can provide complex information about flocs and may lead to a better understanding of the activated sludge process and more effective control of the process performance. In this paper, the results of a recent study concerning the physical properties and structure of the activated sludge flocs are presented.
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