scholarly journals Simultaneous removal of Fe3+ and nitrate in the autotrophic denitrification immobilized systems

2017 ◽  
Vol 18 (5) ◽  
pp. 1625-1634
Author(s):  
Jun feng Su ◽  
Ting ting Lian ◽  
Ting lin Huang ◽  
Dong hui Liang ◽  
Wen dong Wang
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Simultaneous Removal ◽  
Autotrophic Denitrification ◽  
Four Levels ◽  
Experimental Group

Abstract In this study, strain CC76, identified as Enterobacter sp., was tested for the reduction of Fe3+ and denitrification using immobilized pellets with strain CC76 as experimental group (IP) and immobilized pellets with strain CC76 and magnetite powder as experimental group (IPM) in the autotrophic denitrification immobilized systems (ADIS). Compared with IP, a higher nitrate removal rate was obtained with IPM by using three levels of influent Fe3+ (0, 5, and 10 mg/L), four levels of pH (5.0, 6.0, 7.0, and 8.0), and three levels of hydraulic retention time (HRT) (12, 14, and 16 h), respectively. Furthermore, response surface methodology (RSM) analysis demonstrated that the optimum removal ratios of nitrate of 87.21% (IP) and 96.27% (IPM) were observed under the following conditions: HRT of 12 h, pH of 7.0 and influent Fe3+ concentration of 5 mg/L (IP) and 1 mg/L (IPM).

Autotrophic denitrification of landfill leachate using elemental sulphur

1996 ◽  
Vol 34 (5-6) ◽  
pp. 469-476 ◽  
Author(s):  
A. Koenig ◽  
L. H. Liu
Keyword(s):  
Particle Size ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Nitrate Removal ◽  
Packed Bed ◽  
Elemental Sulphur ◽  
Limiting Factor ◽  
Autotrophic Denitrification ◽  
Sulphur Particle

One of the most economical means of nitrogen removal from leachate is biological treatment by nitrification, followed by heterotrophic denitrification. An alternative biological denitrification process is autotrophic denitrification using Thiobacillus denitrificans. This autotrophic bacteria oxidizes elemental sulphur to sulphate while reducing nitrate to elemental nitrogen gas, thereby eliminating the need for addition of organic carbon compounds. For this study, pilot-scale elemental sulphur packed bed columns with fixed-film denitrification have been selected as the most suitable treatment process. The effect of hydraulic retention time as well as the effect of concentration and loading rate of nitrate on nitrate removal efficiency as a function of sulphur particle size were determined. The results indicate that (i) autotrophic denitrification can effectively remove nitrate from synthetic and actual nitrified leachate at concentrations much higher than hitherto reported; (ii) the minimum hydraulic retention time necessary for complete denitrification depends on sulphur particle size; (iii) the maximum area loading rate, in g NO3−-N/m2·d, appears to be the process limiting factor and is practically independent of sulphur particle size; and (iv) the observed stoichiometric relationships compare well with those previously reported.

scholarly journals Evaluating the Effect of pH, Temperature, and Hydraulic Retention Time on Biological Sulphate Reduction Using Response Surface Methodology

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2662
Author(s):  
Mukhethwa Judy Mukwevho ◽  
Dheepak Maharajh ◽  
Evans M. Nkhalambayausi Chirwa
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Mine Drainage ◽  
Reduction Rate ◽  
Sulphate Reduction ◽  
Promising Alternative ◽  
Effect Of Ph ◽  
Independent Variables

Biological sulphate reduction (BSR) has been identified as a promising alternative for treating acid mine drainage. In this study, the effect of pH, temperature, and hydraulic retention time (HRT) on BSR was investigated. The Box–Behnken design was used to matrix independent variables, namely pH (4–6), temperature (10–30 °C), and HRT (2–7 days) with the sulphate reduction efficiency and sulphate reduction rate as response variables. Experiments were conducted in packed bed reactors operating in a downflow mode. Response surface methodology was used to statistically analyse the data and to develop statistical models that can be used to fully understand the individual effects and the interactions between the independent variables. The analysis of variance results showed that the data fitted the quadratic models well as confirmed by a non-significant lack of fit. The temperature and HRT effect were significant (p < 0.0001), and these two variables had a strong interaction. However, the influence of pH was insignificant (p > 0.05).

Effect of nitrate concentration, pH, and hydraulic retention time on autotrophic denitrification efficiency with Fe(II) and Mn(II) as electron donors

2016 ◽  
Vol 74 (5) ◽  
pp. 1185-1192 ◽  
Author(s):  
Jun-feng Su ◽  
Jing-xin Shi ◽  
Ting-lin Huang ◽  
Fang Ma ◽  
Jin-suo Lu ◽  
...  
Keyword(s):  
Electron Donor ◽  
Retention Time ◽  
Hydraulic Retention Time ◽  
Nitrate Concentration ◽  
Nitrate Removal ◽  
Electron Donors ◽  
Autotrophic Denitrification ◽  
Weakly Alkaline ◽  
Removal Ratio

The role of electron donors (Fe2+ and Mn2+) in the autotrophic denitrification of contaminated groundwater by bacterial strain SY6 was characterized based on empirical laboratory-scale analysis. Strain SY6 can utilize Fe2+ more efficiently than Mn2+ as an electron donor. This study has shown that the highest nitrate removal ratio, observed with Fe2+ as the electron donor, was approximately 88.89%. An immobilized biological filter reactor was tested by using three levels of influent nitrate (10, 30, and 50 mg/L), three pH levels (6, 7, and 8), and three levels of hydraulic retention time (HRT; 6, 8, and 12 h), respectively. An optimal nitrate removal ratio of about 95% was achieved at pH 6.0 using a nitrate concentration of 50 mg/L and HRT of 12 h with Fe2+ as an electron donor. The study showed that 90% of Fe2+ and 75.52% removal of Mn2+ were achieved at pH 8.0 with a nitrate concentration of 50 mg/L and a HRT of 12 h. Removal ratio of Fe2+ and Mn2+ is higher with higher influent nitrate and HRT. A weakly alkaline environment assisted the removal of Fe2+ and Mn2+.

Quantification of tool chatter and metal removal rate using wavelet denoising and statistical approach

2018 ◽  
Vol 49 (2) ◽  
pp. 62-81 ◽  
Author(s):  
Shailendra Kumar ◽  
Bhagat Singh
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Metal Removal ◽  
Removal Rate ◽  
Statistical Significance ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Metal Removal Rate ◽  
Chatter Index ◽  
Tool Chatter

Tool chatter is an unavoidable phenomenon encountered in machining processes. Acquired raw chatter signals are contaminated with various types of ambient noises. Signal processing is an efficient technique to explore chatter as it eliminates unwanted background noise present in the raw signal. In this study, experimentally recorded raw chatter signals have been denoised using wavelet transform in order to eliminate the unwanted noise inclusions. Moreover, effect of machining parameters such as depth of cut ( d), feed rate ( f) and spindle speed ( N) on chatter severity and metal removal rate has been ascertained experimentally. Furthermore, in order to quantify the chatter severity, a new parameter called chatter index has been evaluated considering aforesaid denoised signals. A set of 15 experimental runs have been performed using Box–Behnken design of experiment. These experimental observations have been used to develop mathematical models for chatter index and metal removal rate considering response surface methodology. In order to check the statistical significance of control parameters, analysis of variance has been performed. Furthermore, more experiments are conducted and these results are compared with the theoretical ones in order to validate the developed response surface methodology model.

Simultaneous removal of nitrogen and phosphorus in a two-biofilter system

2000 ◽  
Vol 41 (12) ◽  
pp. 101-106 ◽  
Author(s):  
D. Pak ◽  
W. Chang
Keyword(s):  
Retention Time ◽  
Phosphorus Removal ◽  
Hydraulic Retention Time ◽  
Loading Rate ◽  
Aerobic Condition ◽  
Nitrogen Loading ◽  
Simultaneous Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Factors Affecting

A two-biofilter system operated under alternate conditions of anaerobic/aerobic was tested to simultaneously remove nitrogen and phosphorus from sewage. The factors affecting simultaneous removal of nitrogen and phosphorus by the two-biofilter system were investigated. Those factors appeared to be influent COD/T-N and COD/T-P ratio, nitrogen loading rate and hydraulic retention time. Nitrite and nitrate produced in the biofilter in aerobic condition affected phosphorus removal by the two-biofilter system. The amount of biomass wasted during the backwash procedure also affected total nitrogen and phosphorus removal by the system.

Sign in / Sign up

Export Citation Format

Share Document