Dynamics of phosphorus and organic substrates in anaerobic and aerobic phases of a sequencing batch reactor

1994 ◽  
Vol 30 (6) ◽  
pp. 237-246 ◽  
Author(s):  
A. Carucci ◽  
M. Majone ◽  
R. Ramadori ◽  
S. Rossetti

This paper describes a lab-scale experimentation carried out to study enhanced biological phosphate removal (EBPR) in a sequencing batch reactor (SBR). The synthetic feed used was based on peptone and glucose as organic substrate to simulate the readily biodegradable fraction of a municipal wastewater (Wentzel et al., 1991). The experimental work was divided into two runs, each characterized by different operating conditions. The phosphorus removal efficiency was considerably higher in the absence of competition for organic substrate between P-accumulating and denitrifying bacteria. The activated sludge consisted mainly of peculiar microorganisms recently described by Cech and Hartman (1990) and called “G bacteria”. The results obtained seem to be inconsistent with the general assumption that the G bacteria are characterized by anaerobic substrate uptake not connected with any polyphosphate metabolism. Supplementary anaerobic batch tests utilizing glucose, peptone and acetate as organic substrates show that the role of acetate in the biochemical mechanisms promoting EBPR may not be so essential as it has been assumed till now.

1995 ◽  
Vol 31 (2) ◽  
pp. 35-43 ◽  
Author(s):  
A. Carucci ◽  
K. Lindrea ◽  
M. Majone ◽  
R. Ramadori

The operation of an anaerobic/aerobic Sequencing Batch Reactor (SBR) with synthetic feed (glucose as the sole organic substrate) demonstrated periods of non-EBPR and EBPR operation in the absence of polyhydroxy alkanoate (PHA) storage. The glucose added as feed disappeared rapidly (within 10 minutes) and none of the normal fermentation products were detected in the supernatant in either mode of operation. Anaerobic/aerobic batch trials using the biomass from the SBR were conducted to examine the processes taking place and a rapid uptake of glucose was confirmed and was accompanied by a fall in pH. The biomass also demonstrated that anaerobic PHB storage occurred when acetate feed was used. The biomass was characterized by a large population of “G” bacteria, the absence of filamentous microorganisms, compact floc structure and high total carbohydrate (ca 40% w/w). The supernatant was characterized by low COD, TOC and the virtual absence of the glucose substrate. The observations indicate that EBPR was possible under circumstances which are not consistent with accepted mechanisms.


2016 ◽  
Vol 51 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Kshitij Ranjan ◽  
Shubhrasekhar Chakraborty ◽  
Mohini Verma ◽  
Jawed Iqbal ◽  
R. Naresh Kumar

Sequencing batch reactor (SBR) was assessed for direct co-treatment of old landfill leachate and municipal wastewater for chemical oxygen demand (COD), nutrients and turbidity removal. Nitrogen removal was achieved by sequential nitrification and denitrification under post-anoxic conditions. Initially, SBR operating conditions were optimized by varying hydraulic retention time (HRT) at 20% (v/v) landfill leachate concentration, and results showed that 6 d HRT was suitable for co-treatment. SBR performance was assessed in terms of COD, ammonia, nitrate, phosphate, and turbidity removal efficiency. pH, mixed liquor suspended solids, mixed liquor volatile suspended solids (MLVSS), and sludge volume index were monitored to evaluate stability of SBR. MLVSS indicated that biomass was able to grow even at higher concentrations of old landfill leachate. Ammonia and nitrate removal efficiency was more than 93% and 83%, respectively, whereas COD reduction was in the range of 60–70%. Phosphate and turbidity removal efficiency was 80% and 83%, respectively. Microbial growth kinetic parameters indicated that there was no inhibition of biomass growth up to 20% landfill leachate. The results highlighted that SBR can be used as an initial step for direct co-treatment of landfill leachate and municipal wastewater.


2006 ◽  
Vol 53 (9) ◽  
pp. 63-70 ◽  
Author(s):  
X. Wang ◽  
M. Ji ◽  
J.F. Wang ◽  
Z. Liu ◽  
Z.Y. Yang

An unusual phenomenon of anaerobic phosphate uptake under alternating anaerobic/aerobic condition was observed in a granular sludge sequencing batch reactor, fed with acetate as sole organic substrate. Anaerobic phosphate uptake efficiencies remained at 50–70% as the influent P/COD was increased from 2/100 to 4/100, and results showed that anaerobic uptake of phosphate was correlated with anaerobic absorption of acetate. Excluding the main possibility of chemical phosphate removal, it appeared that phosphate uptake during the anaerobic phase was associated with organisms enriched in the reactor. Moreover, results indicated that intracellular glycogen was used as the main energy source of organics anaerobic absorption and intracellular polymers storage. Measuring and analysing the variation of phosphate, organic substrate, intracellular glycogen and pH in the anaerobic phase, a preliminary explanation was developed that anaerobic uptake of phosphate was the demand of intracellular glycogen degradation, and extracellular phosphate was transported to intracellular by pH gradient-sensitive phosphate carrier protein.


1991 ◽  
Vol 23 (7-9) ◽  
pp. 1405-1415 ◽  
Author(s):  
Simón González-Martinez ◽  
Peter A. Wilderer

Biological phosphate removal was achieved in a laboratory scale fixed bed biofilm reactor. To create the conditions required to enrich for phosphate accumulating bacteria, the reactor was periodically filled and drained, and the aerator periodically turned on and off (Sequencing Batch Reactor strategy). The reactor performed very effectively, but it took several weeks to reach steady-state. The highest phosphate uptake rates were observed when sequestration of the organic substrates was accomplished at an early stage of the anaerobic process phase, and release of phosphate at the expense of sequestered or stored substrates (endogenous phosphate release) was encouraged. In the range between 15°C to 25°C, the temperature had only minor effects. The biofilm dry weight contained about 5 per cent phosphate.


2007 ◽  
Vol 73 (7) ◽  
pp. 2257-2270 ◽  
Author(s):  
Johwan Ahn ◽  
Sarah Schroeder ◽  
Michael Beer ◽  
Simon McIlroy ◽  
Ronald C. Bayly ◽  
...  

ABSTRACT All activated sludge systems for removing phosphate microbiologically are configured so the biomass is cycled continuously through alternating anaerobic and aerobic zones. This paper describes a novel aerobic process capable of decreasing the amount of phosphate from 10 to 12 mg P liter−1 to less than 0.1 mg P liter−1 (when expressed as phosphorus) over an extended period from two wastewaters with low chemical oxygen demand. One wastewater was synthetic, and the other was a clarified effluent from a conventional activated sludge system. Unlike anaerobic/aerobic enhanced biological phosphate removal (EBPR) processes where the organic substrates and the phosphate are supplied simultaneously to the biomass under anaerobic conditions, in this aerobic process, the addition of acetate, which begins the feed stage, is temporally separated from the addition of phosphate, which begins the famine stage. Conditions for establishing this process in a sequencing batch reactor are detailed, together with a description of the changes in poly-β-hydroxyalkanoate (PHA) and poly(P) levels in the biomass occurring under the feed and famine regimes, which closely resemble those reported in anaerobic/aerobic EBPR processes. Profiles obtained with denaturing gradient gel electrophoresis were very similar for communities fed both wastewaters, and once established, these communities remained stable over prolonged periods of time. 16S rRNA-based clone libraries generated from the two communities were also very similar. Fluorescence in situ hybridization (FISH)/microautoradiography and histochemical staining revealed that “Candidatus Accumulibacter phosphatis” bacteria were the dominant poly(P)-accumulating organisms (PAO) in both communities, with the phenotype expected for PAO. FISH also identified large numbers of betaproteobacterial Dechloromonas and alphaproteobacterial tetrad-forming organisms related to Defluviicoccus in both communities, but while these organisms assimilated acetate and contained intracellular PHA during the feed stages, they never accumulated poly(P) during the cycles, consistent with the phenotype of glycogen-accumulating organisms.


1994 ◽  
Vol 29 (7) ◽  
pp. 109-117 ◽  
Author(s):  
J. S. Čech ◽  
P. Hartman ◽  
M. Macek

Population dynamics of polyphosphate-accumulating bacteria (PP bacteria) was studied in a laboratory sequencing batch reactor simulating anaerobic-oxic sludge system. The competition between PP bacteria and another microorganism (“G bacteria”) for anaerobic-oxic utilization of acetate as the sole source of organic carbon was observed. The competition was found to be seriously influenced by protozoan and metazoan grazing: Predation-resistant “G bacteria” forming large compact flocs outcompeted PP bacteria. Several breakdowns of enhanced biological phosphorus removal were observed. The first one was related to the development of an euglenid flagellate Entosiphon sulcatus and attached ciliates Vorticella microstoma and V. campanula. The second system collapse was connected with a rapid proliferation of rotifers. An alternative-prey predation was thought to be a mechanism of PP bacteria elimination.


Vestnik MGSU ◽  
2019 ◽  
pp. 589-602 ◽  
Author(s):  
Tran Ha Quan ◽  
Elena S. Gogina

Introduction. Vietnamese urban municipal wastewater treatment plants are mainly of aeration-type facilities. Nowadays, an aeration-type plant, the Sequencing Batch Reactor (SBR), is widely applied and possesses a number of advantages over traditional systems with suspended activated sludge. Advantages of the SBR are mainly concluded in simplicity of operation, occupied area and cost. There is a number of problems at the wastewater treatment plants; they are connected with supplying only a half of wastewater design amount for the treatment as well as with quality of the purified water that must satisfy requirements of the Vietnamese discharge standard, the Standard A. Therefore, reconstruction and modification of the SBR is the major challenger to ensure the sustained development of large Vietnamese cities and maintenance of ecological balance. Materials and methods. To enhance the efficiency of wastewater purification in the SBR, the experiments were set on reactor reconstruction and modification by two directions: (1) Technological method, i.e. applying the Biochip 25 biocarrier, and (2) Operation method, i.e. adding the anoxic phase in reactor operation cycle. Laboratory tests were conducted for each of the directions, including comparison of a typical reactor with the modified one. Results. The study resulted in obtaining an optimal amount of the BioChip biocarrier material (10 to 20 %) that increased efficiency of wastewater purification by 10 to 20 %. In addition to this, when creating an anoxic phase of the operation cycle, efficiency of nitrogen removal increased by 20 %. When the denitrification occurs under the anoxic conditions, it contributes to stabilization of ammonium nitrogen removal for daily nitrogen loading in reactor of 0.3 to 0.8 TKN kg/sludge kg. Conclusions. The suggested technology provides the quality of treated water corresponding with the Vietnamese Standard A requirements. At the present, it is planned to proceed with the experiment on the base of Vietnamese semi-industrial plant for research and appraisal of the SBR reconstruction and modification method. Acknowledgements. The authors are grateful to AKVA Control company in Samara for granted biocarrier Mutag BioChip 25 and to Associate Professor Tran Van Quang and his students, Nguyen Ngoc Phuong and Truong Quoc Dai, of Environment Protect Research Center, Danang University for support of the experiment.


2000 ◽  
Vol 41 (1) ◽  
pp. 97-104 ◽  
Author(s):  
J.C. Akunna ◽  
C. Jefferies

Field trials were carried out using two types of package units designed for the treatment of domestic sewage from individual households. One of the units was a commercially available rotating biological contactor (RBC) system. The other was a newly developed sequencing batch reactor (SBR) system. Trials were carried at the site of a local sewage treatment plant where degritted raw sewage from a combined sewerage network was fed to the two units for a period of four months. Both units produced good effluent quality, well below 20/30 (BOD/SS) during steady-state performance. However, shorter start-up time was observed with the SBR unit together with better effluent quality (up to BOD<10 mg/l and SS<15 mg/l). Furthermore, the SBR unit produced effluents with ammonia nitrogen and total phosphorus levels of 3 mg/l and 2 mg/l respectively, for influent levels that varied from 20 to 60 mg N-NH3/l and from 15 to 17 mg/l of total phosphorus. On the other hand, significant nutrient removal did not seem tohave occurred in the RBC unit. During testing to meet the requirements of British Standard (BS 6297), it was observed that the SBR can tolerate shockloads and periods following zero flow better than the RBC unit.


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