Effects of pH shock on microaerobic activated sludge system with a graphene oxide/nano-magnetic powder composite

2020 ◽  
Vol 35 (3) ◽  
pp. 457-463
Author(s):  
Huixia Lan ◽  
Xiangzhi Wang ◽  
Shixin Qi ◽  
Da Yang ◽  
Hao Zhang
Keyword(s):  
Graphene Oxide ◽  
Activated Sludge ◽  
High Throughput Sequencing ◽  
Impact Resistance ◽  
Magnetic Powder ◽  
Blank Group ◽  
Activated Sludge System ◽  
Ph Shock ◽  
Dominant Bacteria ◽  
The Impact

AbstractUsing the acclimated activated sludge from the pulping middle-stage effluent, the effect of pH shock on the micro-oxygen activated sludge system with a nano-magnetic powder/graphene oxide composite was studied. The results showed that the removal rates of chemical oxygen demand (CODCr) and ultraviolet adsorption at 254 nm (UV254) decreased. Also, the sludge settling performance was poor due to the impact of pH, but the impact resistance of nano-magnetic powder/graphene oxide group (MGO group) was higher and the recovery was faster. Results of high throughput sequencing indicated that the diversity of microbial community was reduced by the impact of pH, but it was significantly higher in MGO group than in the blank group. The dominant bacteria after pH shock or recovery in both of the system had a large difference. The percentage of the dominant bacteria in the MGO group was higher than that in the blank group. The MGO group had higher electron transfer system (ETS) activity which made the system having a strong pH impact resistance.

Study on pH Shock Resistance of the Magnetic Micro-Aerobic Activated Sludge System

2013 ◽  
Vol 807-809 ◽  
pp. 1441-1444
Author(s):  
Hui Xia Lan ◽  
Rui Chen ◽  
Ping Ma ◽  
Heng Zhang ◽  
Shan Hong Lan
Keyword(s):  
Activated Sludge ◽  
Removal Efficiency ◽  
Magnetic Powder ◽  
Effect Of Ph ◽  
Activated Sludge System ◽  
Low Load ◽  
Ph Shock ◽  
Shock Resistance ◽  
Recovery Experiment

the effect of pH shock on the magnetic micro-aerobic activated sludge system used to deal with low load glucose wastewater was studied. After pH shocking under the condition of pH=6.0 and 9.0 for 15 days, CODCr removal efficiency of the reactor with magnetic powder was higher than that of the reactor without magnetic powder, and remained above 80% in the 5 days recovery experiment at pH=7.5, while about 50% of the reactor without magnetic powder. SVI in the reactor with magnetic powder was lower than that of the reactor without magnetic powder after pH shocking, and after the 5 days' recovery experiments, SVI of the sludge with magnetic powder could recovered to the original value, but the indicators of the sludge without magnetic powder could not recovered to the original value.

Inhibition of sulfide generation by dosing formaldehyde and its derivatives in sewage under anaerobic conditions

2008 ◽  
Vol 57 (6) ◽  
pp. 915-919 ◽  
Author(s):  
L. Zhang ◽  
L. Mendoza ◽  
M. Marzorati ◽  
W. Verstraete
Keyword(s):  
Hydrogen Sulfide ◽  
Oxygen Uptake ◽  
Activated Sludge ◽  
Oxygen Uptake Rate ◽  
Urea Formaldehyde ◽  
Nitrification Rate ◽  
Economic Aspects ◽  
Anaerobic Conditions ◽  
Activated Sludge System ◽  
The Impact

Hydrogen sulfide emission in sewers is associated with toxicity, corrosion, odor nuisance and a lot of costs. The possibility to inhibit sulfide generation by formaldehyde and its derivatives (paraformaldehyde and urea formaldehyde) has been evaluated under anaerobic conditions. The impact of formaldehyde on an activated sludge system and an appraisal of the economic aspects are also presented. The optimum dosage to inhibit sulfide generation in sewage was 12–19 mg L−1 formaldehyde. The dosages of 32 mg L−1 paraformaldehyde or 100 mg L−1 urea formaldehyde were not capable of inhibiting sulfide generation in sewage. The impact of 19 mg L−1 formaldehyde on activated sludge system was negligible in terms of COD removal, nitrification rate and oxygen uptake rate.

Biodegradation of Mixed Cultures on Azo Dyes and the Bioaugmentation Effects of the Activated Sludge System

2011 ◽  
Vol 183-185 ◽  
pp. 301-305
Author(s):  
Feng Xu
Keyword(s):  
Activated Sludge ◽  
Manganese Peroxidase ◽  
Impact Resistance ◽  
Mixed Cultures ◽  
Oxidative Enzymes ◽  
Augmented System ◽  
Activated Sludge System ◽  
Direct Blue ◽  
Degradation Rates ◽  
High Level

The biodegradation of mixed cultures was analyzed. The paper studied the effects of treat condition (static and shaking), concentration of dye, activities of oxidative enzymes (LiP, laccase and Manganese Peroxidase) and the bioaugmentation effects of the activated sludge system. The results showed that mixed cultures were able to degrade Reactive Brilliant Red X-3B and Direct Blue-6 (100 mg/L) completely within 32 h in shaking condition. As the initial concentration of Reactive Brilliant Red X-3B increased from 100mg/L to 900mg/L, the decolorization rate still maintain a high level only decreased from 99.3% to 83.5%. Induction in the activity of oxidative enzymes (LiP, laccase and Manganese Peroxidase) represented their role in degradation. In augmented experiments, it showed that in the control SBR system with the CODCr of the effluent was in three average levels 848, 1228, and 1550 mg/L, the CODCr degradation rates were 42.3%, 32.8% and 19.7%. In the augmented system treated with the same effluent, the degradation rates of augmented system were 86.5%, 71.8% and 59.8% respectively. It showed that the activated sludge was augmented by the mixed cultures which made the system to be more stable and improve impact resistance.

Research for Biodegradation and Bioaugmentation of Drilling Wastewater

2013 ◽  
Vol 684 ◽  
pp. 226-229
Author(s):  
Feng Xu ◽  
Jin Chuan Gu ◽  
Jin Bao
Keyword(s):  
Activated Sludge ◽  
Degradation Rate ◽  
Orthogonal Experiment ◽  
Impact Resistance ◽  
Single Strain ◽  
Optimal Ratio ◽  
Augmented System ◽  
Activated Sludge System ◽  
Degradation Rates ◽  
Drilling Site

The paper studied the degradation rate of single strain, the microorganisms agent compatibility and the bioaugmentation effects of the activated sludge system. The results showed that 10 strains screened from drilling site were able to degrade drilling wastewater. Confirm the optimal ratio of strains’ compatibility through orthogonal experiment. In augmented experiments, it showed that in the control SBR system with the COD of the effluent was in three different average levels (with two load shock), the COD degradation rates were 21.4%, 22.8% and 6.9%. In the augmented system treated with the same effluent, the degradation rates of augmented system were 64.8%, 62.78% and 66.9% respectively. It showed that the activated sludge was augmented by the mixed cultures which made the system to be more stable and improve impact resistance.

scholarly journals Modelling and Optimization of the Impact Resistance of Graphene Oxide Modified Crumb Rubber-ECC Using Response Surface Methodology

2021 ◽  
Vol 1197 (1) ◽  
pp. 012043
Author(s):  
Isyaka Abdulkadir ◽  
Bashar S. Mohammed ◽  
M. S. Liew ◽  
M. M. A. Wahab
Keyword(s):  
Response Surface Methodology ◽  
Graphene Oxide ◽  
Response Surface ◽  
Predictive Models ◽  
Impact Resistance ◽  
Crumb Rubber ◽  
Test Method ◽  
Fine Aggregate ◽  
The Impact

Abstract This paper presents the findings of an investigation on the impact resistance of graphene oxide (GO) modified rubberized engineered cementitious composite (GOCRECC) and the development of response-predictive models and optimization using response surface methodology (RSM). The input factors considered as the independent variables were the GO at 0, 0.02, 0.04, 0.06 and 0.08% addition by cement weight and crumb rubber (CR) at 1, 3 and 5% replacement of fine aggregate. Fifteen mixes having different quantities of input factors were used for the determination of the initial (E1) and ultimate (E2) impact energy using the ACI 544. R drop weight impact test method. The results showed that impact resistance of the GOCRECC mixes increased with increasing contents of the input factors. Response predictive models for E1 and E2 were developed and found to have high R2 values of 78 and 93% respectively, after validation using the analysis of variance (ANOVA). The optimization performed yielded an optimal amounts of the input factors of 0.0347 and 5% for GO and CR respectively at a desirability value of 74%.

Effect of combined drink cans and steel fibers on the impact resistance and mechanical properties of concrete

2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Impact Resistance ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Indirect Tensile ◽  
The Impact

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    

Oxidation Ditch

2018 ◽  
Author(s):  
Gede H Cahyana
Keyword(s):  
Activated Sludge ◽  
Special Form ◽  
Oxidation Ditch ◽  
End Point ◽  
Activated Sludge System

As a part of activated sludge system, oxidation ditch has a special form like a canal without end point. Rotor is used to diffuse oxygen from air to the water.

Parameters for Measuring the Activity and Viability of Activated Sludge

1974 ◽  
Vol 9 (1) ◽  
pp. 235-249 ◽  
Author(s):  
S.G. Nutt ◽  
K.L. Murphy
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Biological System ◽  
Analytical Methods ◽  
Heterogeneous System ◽  
Removal Rate ◽  
Bacterial Species ◽  
Atp Content ◽  
Culture Studies ◽  
Activated Sludge System

Abstract Conventional wastewater parameters are accepted as inadequate estimates of the condition of activated sludge but numerous other indices have been suggested as specific measurements of the activity and viability of the biomass. Literature in the related fields of microbiology and biochemistry were reviewed in order to select the most appropriate activity parameters for application to a heterogeneous biological material. Modified analytical methods were applied to a well-controlled biological system containing a single predominant bacterial species to evaluate the relative merit of each as an indicator of viability and activity. The potential of each parameter in a complex heterogeneous system was determined by monitoring each index in a bench activated sludge system. The predominant culture studies indicated that the ATP content of the biomass and the dehydrogenase activity were potential indicators of cell viability in a simple system. However, in the complex activated sludge system, only the ATP content showed significant correlation to the organic carbon removal rate.

The Impact of a Chemostat Discharge Containing Oil Degrading Bacteria on the Biological Kinetics of a Refinery Activated Sludge Process

1988 ◽  
Vol 20 (11-12) ◽  
pp. 131-136 ◽  
Author(s):  
A. D. Wong ◽  
C. D. Goldsmith
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Waste Treatment ◽  
Treatment Plant ◽  
Utilization Rate ◽  
Activated Sludge Process ◽  
Kinetic Evaluation ◽  
Degrading Bacteria ◽  
Waste Treatment Plant ◽  
The Impact

The effect of discharging specific oil degrading bacteria from a chemostat to a refinery activated sludge process was determined biokinetically. Plant data for the kinetic evaluation of the waste treatment plant was collected before and during treatment. During treatment, the 500 gallon chemostatic growth chamber was operated on an eight hour hydraulic retention time, at a neutral pH, and was fed a mixture of refinery wastewater and simple sugars. The biokinetic constants k (days−1), Ks (mg/L), and K (L/mg-day) were determined before and after treatment by Monod and Lineweaver-Burk plots. Solids discharged and effluent organic concentrations were also evaluated against the mean cell retention time (MCRT). The maximum utilization rate, k, was found to increase from 0.47 to 0.95 days−1 during the operation of the chemostat. Subsequently, Ks increased from 141 to 556 mg/L. Effluent solids were shown to increase slightly with treatment. However, this was acceptable due to the polishing pond and the benefit of increased ability to accept shock loads of oily wastewater. The reason for the increased suspended solids in the effluent was most likely due to the continual addition of bacteria in exponential growth that were capable of responding to excess substrate. The effect of the chemostatic addition of specific microbial inocula to the refinery waste treatment plant has been to improve the overall organic removal capacity along with subsequent gains in plant stability.

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