Effect Of Aeration Time Research Articles

Performance of anaerobic/oxic/anoxic simultaneous nitrification, denitrification and phosphorus removal system overwhelmingly dominated by Candidatus_Competibacter: Effect of aeration time

The anaerobic/oxic/anoxic simultaneous nitrification, denitrification and phosphorus removal process (AOA-SNDPR) is a promising technology for enhanced biological wastewater treatment and in situ sludge reduction. Herein, effects of aeration time (90, 75, 60, 45, and 30 min, respectively) on the AOA-SNDPR were evaluated including simultaneous nutrients removal, sludge characteristics, and microbial community evolution, where the role of a denitrifying glycogen accumulating organisms, Candidatus_Competibacter, was re-explored given its overwhelming dominance. Results revealed that nitrogen removal was more vulnerable, and a moderate aeration period of 45–60 min favored nutrients removal most. Low observed sludge yields (Yobs) were obtained with decreased aeration (as low as 0.02–0.08 g MLSS/g COD), while MLVSS/MLSS got increased. The dominance of Candidatus_Competibacter was identified as the key to endogenous denitrifying and in situ sludge reduction. This study would aid the low carbon- and energy-efficient aeration strategy for AOA-SNDPR systems treating low-strength municipal wastewater.

Influence Modeling and optimization of sulphide removal by catalytic oxidation of tannery fur effluents [Modelamiento y optimización de la remoción de sulfuros por oxidación catalítica de efluentes de pelambre de curtiduría

The residual effluents from the fur stage of the bovine leather tannery industry are characterized by having a high concentration of sulfides. The objective of this study was to evaluate the effects of aeration time and pH in the residual effluents of the leather stage of the tannery, with the catalysts MnO2 and MnSO4 separately; as well as, determine adjustment models through the response surface methodology and the optimal intervals of the best conditions that lead to a higher percentage of sulfide removal. For this reason, the sulphide removal percentage was evaluated from samples extracted from the pellet stage, by means of catalytic oxidation treatments; varying the catalyst, pH and aeration time. The catalysts used were manganese dioxide (MnO2) and manganese sulfate (MnSO4) and for each catalyst the pH was varied in the values ​​of 8.5; 9.5; 10.2 and 13.4; likewise, the aeration time was varied in the values ​​of 30, 60, 90, 120, 150, 180, 210 and 240 minutes. 64 treatments were carried out, with 3 repetitions each, reporting the average values ​​of the sulfide removal percentage. The response surface methodology was used to adjust the correlation of the variables to a quadratic model; Likewise, through contour graphs the regions with the highest percentage of sulfide removal were easily identified and by superimposing contour graphs the optimal ranges of the variables pH and aeration time were determined for removal percentages greater than 98%. Based on this evaluation, it is proposed for treatments with manganese dioxide, aeration times between 160 to 240 min and pH between 8.5 to 9 and for treatments with manganese sulfate, aeration times between 110 to 240 min and pH between 8.5 to 9.8. The coefficients of multiple determination R2 for the models with catalyst MnO2 and MnSO4 were 97.51% and 95.12% respectively. With the MnSO4 catalyst, higher removal percentages were achieved at a shorter aeration time, compared to the treatments carried out with the MnO2 catalyst.

Numerical simulation of micro-nano bubble central intake aeration

In this paper, ANSYS FLUENT was used to simulate the gas-liquid two-phase flow in the process of micro-nano bubble aeration and optimized the central air intake aeration conditions. The particle size of microbubbles was 2 μm, the Eulerian model was used in multiphase flow model, and the standard k - ε model was used in turbulence model. The gas-liquid two-phase flow field with different aeration velocity was simulated. The effects of aeration time on gas holdup were studied. The results showed that the aeration effect was better with the increase of aeration speed, stronger turbulence, two-phase mixing and oxygen mass transfer.

Study on effect of aeration time on methylene blue removal using titanium dioxide

The aquatic organisms, human beings and other living species are affected due to polluted water excreted from industries. This polluted water contains various chemical substances such as dyes, cyanide etc. One such compound is Methylene blue dye which has an adverse effect on many living organisms. In this study Titanium dioxide (TiO2) nanoparticles was prepared which completely neutralize the effect of Methylene blue in water. The morphology of titanium dioxide has been studied through Scanning Electron Microscope (SEM). The efficiency of prepared nanoparticles has been tested in the presence of sunlight and aeration. The efficiency of Titanium dioxide was 85% at the end of 15 minutes which prohibit the effect of Methylene blue.

Effect of Aeration Time on Preserved Wastewater Treatment of Activated Sludge Process

effects of aeration time on the COD removal rate, turbidity removal rate, pH, conductivity, SS removal rate, absorbance and decolorization rate were investigated by using activated sludge process treatment of a high concentration of preserved wastewater. results showed that with the extension of the aeration time, the wastewater quality improved gradually. treatment effect was the best after the activated sludge treatment of the preserved wastewater for 32 h. Meanwhile, the COD removal rate, turbidity removal rate, pH, conductivity, SS removal rate, absorbance and decoloration rate of the preserved wastewater were 94.2%, 42%, 5.68, 0.247x104, 57.8%, 0.429, and 51.5%, respectively. effluent quality has reached the three-level standard of The Integrated Wastewater Discharge Standard (GB8978-1996).

Effect of aeration time on the operation of SBR and SBBR reactor

Effect of aeration time on the operation of SBR and SBBR reactor

Effect of aeration time on the operation of SBR and SBBR reactor

Effect of aeration time on the operation of SBR and SBBR reactor

Enhanced As(III) removal at low concentrations by the combined pre-oxidation and nanofiltration membrane process

A specially designed combined process of pre-oxidation and nanofiltration membrane was utilized to remove As(III) in the contaminated water without reagent addition and sediment creation in this work. Different parameters that affected the rejections of As(III) and As(V) were discussed, including the initial concentration, pH of the feed, and the cross-flow filtration pressure. The rejection of As(III) was over 70% which was restricted to the high initial feed concentration, while it was around 40% under the other conditions. Whereas, the rejection of As(V) maintained above 95% in all tests. As a result, As(III) was first pre-oxidized before membrane filtration. The ozone and aeration oxidation methods were used to oxidize As(III). The effects of aeration time and oxidation time were studied. The experimental results indicated that the rejection of As(III) was increased to over 90% after pre-oxidation, and the permeate could meet the drinking water standard for As in China. Particularly, the aeration took a much longer oxidation time than ozone, but it was still a more suitable method as the pre-oxidation process because of its safety and easy operability.

Optimization of organics and nitrogen removal in intermittently aerated vertical flow constructed wetlands: Effects of aeration time and aeration rate

In this study, to optimize aeration for the enhancement of organics and nitrogen removal in intermittently aerated vertical flow constructed wetlands (VF CWs) for treating domestic wastewater, the experimental VF CWs were operated at different aeration time (1 h d−1, 2 h d−1, 4 h d−1, 6 h d−1, 8 h d−1 and 10 h d−1) and aeration rate (0.1 L min−1, 0.2 L min−1, 0.5 L min−1, 1.0 L min−1 and 2.0 L min−1) to investigate the effect of artificial aeration on the removal efficiency of organics and nitrogen. The results showed that the optimal aeration time and aeration rate were 4 h d−1 and 1.0 L min−1, which could create the appropriate aerobic and anoxic regions in CWs with the greater removal of COD (97.2%), NH4+-N (98.4%) and TN (90.6%) achieved simultaneously during the experiment. The results demonstrate that the optimized intermittent aeration is reliable option to enhance the treatment performance of organics and nitrogen at a lower operating cost.

Treatment of Rosin Wastewater by Boiler Slag Adsorption and Activated Sludge Biodegradation

In the presented patent, wastewater treatment from pine gum resin processing had been studied and the suitable conditions for treating the wastewater were obtained. This patent utilized two processes: the primary treatment of boiler slag adsorption and the secondary treatment of activated sludge biodegradation. Under the primary treatment, the chemical oxygen demand (COD) and suspended substances (SS) in the wastewater were examined systematically at various slag’s sizes and solution pH values. The suitable technological conditions of the slag adsorption treatment found were boiler slag size of 1.00-1.41 mm and solution pH value of 6.0. The adsorption experimental equilibrium data was found to fit the Langmuir model well, and the breakthrough curve of adsorption column test was also obtained. The effluent treated by the boiler slag adsorption was further treated by activated sludge biodegradation. The effects of aeration time and coagulation/ precipitation time on biodegradation process were studied and the suitable biodegradation conditions obtained were as follows: the coagulation/precipitation time of 60 min, the aeration time of 6 h for COD and aeration time of 8 h for SS, respectively. Keywords: Activated sludge, adsorption, boiler slag, chemical oxygen demand, gum resin processing wastewater, langmuir.

Efeitos da aeração sobre as características da silagem de cana-de-açúcar

This trial aimed at evaluating the deleterious effects of aeration time on nutritive value and other fermentative characteristics of sugarcane silage. A completely randomized design was used with three treatments and four repetitions per treatment. Fresh chopped sugarcane was exposed to aeration for 0, 4 or 8 hours, and ensiled soon after. After exposure, the material was ensiled in 12 laboratory silos (plastic buckets). Silos were opened 85 days after ensiling, when organic acids contents and chemical composition of silages were determined. Deviation of linearity (p in vitro digestibility of dry matter. For organic acids content, deviation of linearity was observed on acetic acid, with the lowest content (1.5% of DM) observed after 8 hours of aeration, and a negative linear effect was observed for lactic and butyric acids, as well as for pH values. There were no effects on ethanol concentration, which remained very high (22% of DM), regardless of aeration time. Aerobic stability of silage worsened with the increase in aeration time.

The Effect of Aeration Time on the Residual Ethylene Oxide Concentration Absorbed in PVC Material Sterilized Within a Reusable Rigid Container

The Effect of Aeration Time on the Residual Ethylene Oxide Concentration Absorbed in PVC Material Sterilized Within a Reusable Rigid Container

Toxic effects of ethylene oxide residues on bovine embryos in vitro

The potential of ethylene oxide (EtO) residues in exposed plastic tissue culture dishes to adversely affect bovine oocyte maturation, fertilization and subsequent embryonic development was monitored. In experiment 1, the effects of aeration time and aeration combined with washing of EtO-gassed culture dishes on the extent of residual toxicity were investigated. There was no cleavage in any treatment in which oocytes were matured and fertilized in dishes exposed to EtO. EtO residues caused functional degeneration of oocytes even when culture dishes were aerated for more than 12 days post EtO-exposure and repeatedly washed. In experiment 2, the residual toxicity of EtO gas on in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) were evaluated. Cleavage rate significantly decreased and post-cleavage development was retarded in ova maintained in dishes treated with EtO either during IVM or IVF. EtO residues may be more detrimental to spermatozoa than to oocytes which may have been the primary cause of fertilization failure during IVF.

Biological Treatment of Chlorhexidine Digluconate-Containing Waste Water. III. Effect of Long Time Aeration on the Treatment Efficiency in Batch Activated Sludge Treatment.

The effect of aeration time on the efficiency of batch activated sludge treatment was experimentally investigated to treat wastewater containing higher concentration of CHG (chlorhexidine digluconate) with the activated sludge acclimated to CHG of constant concentration. 2 ppm and 10 ppm CHG-containing wastewater was charged into the aeration vessel keeping activated sludge acclimated to 0.5 ppm CHG-concentration and treated under the different conditions (6 h, 12 h, 22 h) on aeration time for one month and their treatment efficiency were compared with that of control (CHG : 0.5 ppm, aeration : 6h). The results shown were as follows. The treatment efficiency of both 2 ppm and 10 ppm CHG-containing wastewater under the same aeration time as control was remarkably inferior to that of the control. Longer time aeration, however, remarkably improved the treatment efficiency of all of TOD (Total Oxygen Demand), TOC (Total Organic Carbon), COD (Chemical Oxygen Demand), NH4+ and NO3- except TOD, NH4+ and NO3- in case of 10 ppm CHG-containing wastewater. In case of 10 ppm CHG-containing wastewater, long time aeration was effective for the first 5 d after the starting operation, but the treatment efficiency of TOD, NH4+ and NO3- went down suddenly from 6th day and after then the efficiency of TOD by long time aeration was getting lower and lower day by day. Whereas the effect of long time aeration as to NH4+ and NO3- nearly disappeared after 6th day. NO2- was almost absent in effluent during the experiment.