scholarly journals Effect of magnetic field on biomass properties and their role in biodegradation under condition of low dissolved oxygen

2021 ◽  
Vol 11 (7) ◽  
Author(s):  
Nur Syamimi Zaidi ◽  
Johan Sohaili ◽  
Khalida Muda ◽  
Mika Sillanpää ◽  
Norelyza Hussein
Keyword(s):  
Magnetic Field ◽  
Dissolved Oxygen ◽  
Biomass Concentration ◽  
Aerobic Bacteria ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Great Chance ◽  
Sludge Bulking ◽  
The Magnetic Field ◽  
High Biomass Concentration

AbstractLow condition of dissolved oxygen (DO) is commonly associated with sludge bulking problem that was able to disrupt the efficiency of wastewater treatment performances. Relatively, very little attention was paid to the possibility of applying magnetic field in controlling the bulking problem. Hence, this study aims to investigate the performance of magnetic field on biomass properties and its effect on biodegradation under low condition of DO. Two continuous laboratory-scale sequencing batch reactors—Reactor A (SBRA) and Reactor B (SBRB)—were setup. SBRA was equipped with the magnetic device to exhibit magnetic field of 88 mT, while SBRB acted as a control system. The results showed that the biomass concentration in SBRA was higher compared to SBRB. High biomass concentration in SBRA resulted to better settleability with mean SVI of less than 30 mL/g. SBRA also showed consistently high removal performances of organic and inorganic contents compared to SBRB. These observations confirmed that the magnetic field was able to enhance the biomass properties, which further enhance the biodegradation ability of the aerobic bacteria under low DO condition. This also indicates that under the sludge bulking circumstances, the use of magnetic field stands a great chance in maintaining high biodegradation of the treatment system.

Low dissolved oxygen sludge bulking in sequencing batch reactors

2005 ◽  
Vol 62 (4) ◽  
pp. 415-420 ◽  
Author(s):  
S. H. Hashemi ◽  
A. A. Azimi ◽  
A. Torabian ◽  
G. Nabi Bidhendi ◽  
R. Mahmoodkhani
Keyword(s):  
Dissolved Oxygen ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Low Dissolved Oxygen ◽  
Sludge Bulking

scholarly journals Microbial community similarity and dissimilarity inside and across full-scale activated sludge processes for simultaneous nitrification and denitrification

2020 ◽  
Vol 81 (2) ◽  
pp. 333-344
Author(s):  
Jianfeng Wen ◽  
Mark W. LeChevallier ◽  
Wendong Tao
Keyword(s):  
Microbial Community ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Relative Abundance ◽  
Nitrogen Removal ◽  
Full Scale ◽  
Batch Reactors ◽  
Simultaneous Nitrification And Denitrification ◽  
Sequencing Batch Reactors ◽  
Mixed Liquor

Abstract Simultaneous nitrification and denitrification under low dissolved oxygen conditions is an energy-saving modification of the activated sludge process to achieve efficient nitrogen removal. Geographically distinct full-scale treatment plants are excellent platforms to address the links of microbial community with operating parameters. Mixed liquor samples were collected from a sequencing batch reactor plant, oxidation ditch plant, and step-feed activated sludge plant. Next-Generation Sequencing of the samples showed that the microbial communities were similar at the phylum level among the plants, being dominated by Proteobacteria. Microbial composition of functional groups was similar between the react fill and react phases of the sequencing batch reactors, among four sequencing batch reactors, and among four oxidation ditches. Nitrospira was the only identified genus of autotropic nitrifying bacteria with a relative abundance of 2.2–2.5% in the oxidation ditches and 0.4–0.7% at the other plants. Heterotrophic nitrifying–aerobic denitrifying bacteria were dominated by Dechloromonas with a relative abundance of 0.4–1.0%. Microbial community composition and nitrogen removal mechanisms were related to overall level and local zonation of dissolved oxygen, mixed liquor suspended solids concentration, nitrogen and organic loadings, and solids retention time. Low dissolved oxygen and low organic and nitrogen loadings favored growth of Nitrospira.

Reactive textile dye colour removal in a sequencing batch reactor

2000 ◽  
Vol 42 (5-6) ◽  
pp. 321-328 ◽  
Author(s):  
N.D. Lourenço ◽  
J.M. Novais ◽  
H.M. Pinheiro
Keyword(s):  
Batch Reactor ◽  
Biomass Concentration ◽  
Reactive Dye ◽  
Textile Dye ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Colour Removal ◽  
Removal Capacity ◽  
Almost All ◽  
Remazol Brilliant Violet 5R

Two sequencing batch reactors (SBRs) with sequenced anaerobic/aerobic phases were used to study biological colour removal from a simulated cotton textile effluent containing an azo reactive dye. One of the reactors was daily fed with Remazol Brilliant Violet 5R dye and the other was used as control. When operating with a sludge retention time (SRT) of 15 days the total COD removal was around 80%, with 30% being removed anaerobically. After 40–50 days of acclimatization the colour removal efficiency reached a maximum, stable value of 90% from a feed dye concentration of 90 mg/l, almost all being removed during the anaerobic phase. This colour removal was attributed to microbial degradation rather than adsorption and colour removal capacity was not lost even after a seven-day absence of dye in the fed substrate. The dye-fed reactor experienced a reduction in the ORP values attained during the non-aerated phase, after acclimatization, an effect not observed in the dye-free control. Under denitrifying conditions it was observed that the decolouration levels achieved in the anaerobic phase decreased from 90% to 70% after only two cycles with a feed containing 45–60 mg NO3/l. Reduction of the SRT value from 15 to 10 days reduced the biomass concentration from 2.0 to 1.2 g VSS/l and lowered colour removal levels from 90% to 30–50%. When the SRT value was increased back to 15 days the colour removal capacity of the system was completely recovered, suggesting that with a SRT of 10 days the adequate microbial population could not be installed in the reactors.

Biological ammonia removal from anaerobically pre-treated landfill leachate in sequencing batch reactors (SBR)

2001 ◽  
Vol 43 (3) ◽  
pp. 307-314 ◽  
Author(s):  
G. Yalmaz ◽  
I. Öztürk
Keyword(s):  
Carbon Source ◽  
Landfill Leachate ◽  
Cycle Time ◽  
Biomass Concentration ◽  
Ammonia Removal ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
The Third ◽  
External Carbon Source ◽  
The Difference

The aim of the study was to investigate both the use of the SBR technology in biological ammonia removal from landfill leachate, and the suitability of raw landfill leachate as external carbon source in denitrification step. The SBR was fed with diluted leachate for the first 42 days and then the effluent of UASBR was used as the feed. The SBR was operated intermittently with a cycle time of 24 hours. The effluent NH4+-N values of less than 5 mg NH4+-N L-1 was consistently observed for the initial NH4+-N levels of as high as 1000 mg NH4+-N L-1. The nitrification rates for the first, second and third stages were found as 5.7, 46.8 and 102.8 mg NH4+-N L-1 h-1, respectively. The difference of the nitrification rates in the 2nd and 3rd stages originated from increasing adaptation of the sludge as well as increasing biomass concentration (10.5 mg NH4+-N g-1VSS h-1). No significant accumulation of NO2--N has been observed during the study and NO2--N/NOx--N ratios measured in the 1st aerobic phase and the SBR effluent were less than 7%. The denitrification rates for the second (raw leachate as carbon source) and the third (Ca(CH3COO)2 as carbon source) stages were determined as 45.7 mg NOx--N L-1 h-1 (or 9.85 mg NOx--N g-1VSS h-1) and 125.7 mg NOx--N L-1 h-1 (or 12.88 mg NOx--N g-1VSS h1), respectively.

Dissolved oxygen as a key parameter to aerobic granule formation

2008 ◽  
Vol 58 (4) ◽  
pp. 781-787 ◽  
Author(s):  
B. S. McSwain Sturm ◽  
R. L. Irvine
Keyword(s):  
Dissolved Oxygen ◽  
Shear Force ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Batch Reactors ◽  
Aerobic Granules ◽  
High Shear ◽  
Sequencing Batch Reactors ◽  
Granule Formation ◽  
Substrate Removal

Much research has asserted that high shear forces are necessary for the formation of aerobic granular sludge in Sequencing Batch Reactors (SBRs). In order to distinguish the role of shear and dissolved oxygen on granule formation, two separate experiments were conducted with three bench-scale SBRs. In the first experiment, an SBR was operated with five sequentially decreasing superficial upflow gas velocities ranging from 1.2 to 0.4 cm s−1. When less than 1 cm s−1 shear was applied to the reactor, aerobic granules disintegrated into flocs, with corresponding increases in SVI and effluent suspended solids. However, the dissolved oxygen also decreased from 8 mg L−1 to 5 mg L−1, affecting the Feast/Famine regime in the SBR and the substrate removal kinetics. A second experiment operated two SBRs with an identical shear force of 1.2 cm s−1, but two dissolved oxygen concentrations. Even when supplied a high shear force, aerobic granules could not form at a dissolved oxygen less than 5 mg L−1, with a Static Fill. These results indicate that the substrate removal kinetics and dissolved oxygen are more significant to granule formation than shear force.

Biological phosphorus and nitrogen removal in sequencing batch reactors: effects of cycle length, dissolved oxygen concentration and influent particulate matter

2013 ◽  
Vol 68 (5) ◽  
pp. 982-990 ◽  
Author(s):  
Maneesha P. Ginige ◽  
Ahmet S. Kayaalp ◽  
Ka Yu Cheng ◽  
Jason Wylie ◽  
Anna H. Kaksonen
Keyword(s):  
Particulate Matter ◽  
Dissolved Oxygen ◽  
Cycle Length ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Organic C ◽  
N Removal ◽  
Do Concentration ◽  
Biological Phosphorus ◽  
P Removal

Removal of phosphorus (P) and nitrogen (N) from municipal wastewaters is required to mitigate eutrophication of receiving water bodies. While most treatment plants achieve good N removal using influent carbon (C), the use of influent C to facilitate enhanced biological phosphorus removal (EBPR) is poorly explored. A number of operational parameters can facilitate optimum use of influent C and this study investigated the effects of cycle length, dissolved oxygen (DO) concentration during aerobic period and influent solids on biological P and N removal in sequencing batch reactors (SRBs) using municipal wastewaters. Increasing cycle length from 3 to 6 h increased P removal efficiency, which was attributed to larger portion of N being removed via nitrite pathway and more biodegradable organic C becoming available for EBPR. Further increasing cycle length from 6 to 8 h decreased P removal efficiencies as the demand for biodegradable organic C for denitrification increased as a result of complete nitrification. Decreasing DO concentration in the aerobic period from 2 to 0.8 mg L−1 increased P removal efficiency but decreased nitrification rates possibly due to oxygen limitation. Further, sedimented wastewater was proved to be a better influent stream than non-sedimented wastewater possibility due to the detrimental effect of particulate matter on biological nutrient removal.

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