Effects of step ration on nitrogen removal efficiency in the step-feed anoxic-oxic activated sludge process.

The nitrogen removal efficiency of the step-feed anoxic-oxic activated sludge process, which has two anoxic tanks and two oxic tanks, was theoretically discussed on the basis of the stoichiometry of denitrification and nitrification reactions. As the first step, effluent NH4-N and NO3-N concentrations were formulated with four parameters; 1) a, equivalent ratio of alkalinity to ammonia in influent, 2) b, that of substrate to ammonia, 3) r, step ratio of influent to the second anoxic tank and 4) R, return (+ recycle) sludge ratio. This calculus was done for the possible sixteen (=24) cases which show different reaction patterns in four tanks, and 12 cases out of 16 were found to be available. The effects of step ratio, r were examined in its range of 0 - 1 at a fixed R value, and it was found that the increase of r alters the outcome in a different way depending on the ranges of a and b. Consequently, zoning of a-b coordinates was successfully made, and the optimal r value for maximum total nitrogen removal was obtained in each zone. In addition, the optimal volume allocation of the four tanks was discussed and the ratios were formulated for each zone.

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Operational Results of the Wolfsburg Wastewater Treatment Plant

Water Science & Technology ◽

10.2166/wst.1992.0496 ◽

1992 ◽

Vol 25 (4-5) ◽

pp. 203-209 ◽

Cited By ~ 7

Author(s):

R. Kayser ◽

G. Stobbe ◽

M. Werner

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Nitrogen Content ◽

Total Nitrogen ◽

Nitrogen Removal ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Phosphate Removal ◽

Total Nitrogen Content ◽

Activated Sludge Process

At Wolfsburg for a load of 100,000 p.e., the step-feed activated sludge process for nitrogen removal is successfully in operation. Due to the high denitrification potential (BOD:TKN = 5:1) the effluent total nitrogen content can be kept below 10 mg l−1 N; furthermore by some enhanced biological phosphate removal about 80% phosphorus may be removed without any chemicals.

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Specific organic and nutrient loads in stabilized sludge from municipal treatment plants

Water Science & Technology ◽

10.2166/wst.1996.0342 ◽

1996 ◽

Vol 33 (12) ◽

pp. 243-250 ◽

Cited By ~ 1

Author(s):

O. Nowak ◽

A. Franz ◽

K. Svardal ◽

V. Müller

Keyword(s):

Activated Sludge ◽

Nitrogen Removal ◽

Single Stage ◽

Nutrient Loads ◽

Activated Sludge Process ◽

Waste Sludge ◽

Sludge Stabilization ◽

Nitrogen Loads ◽

Theoretical Considerations ◽

P Removal

By means of theoretical considerations and of statistical evaluations, specific organic and nitrogen loads in separately stabilized sludge have been found to be in the range of 16 to 20g VSS/PE/d and of 1.1 to 1.5 g N/PE/d respectively. About 0.6g P/PE/d are removed from the wastewater in activated sludge plants without chemical or enhanced biological P removal. By using the single-stage activated sludge process without primary sedimentation and without separate sludge stabilization, almost complete nitrogen removal can be achieved, but specific organic and nitrogen loads in the waste sludge are up to two times higher than in separately stabilized sludge.

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Dynamic modeling of nitrogen removal for a three-stage integrated fixed-film activated sludge process treating municipal wastewater

Bioprocess and Biosystems Engineering ◽

10.1007/s00449-017-1862-3 ◽

2017 ◽

Vol 41 (2) ◽

pp. 237-247 ◽

Cited By ~ 3

Author(s):

Paul Moretti ◽

Jean-Marc Choubert ◽

Jean-Pierre Canler ◽

Pierre Buffière ◽

Olivier Pétrimaux ◽

...

Keyword(s):

Activated Sludge ◽

Dynamic Modeling ◽

Nitrogen Removal ◽

Municipal Wastewater ◽

Activated Sludge Process ◽

Fixed Film

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Enhancing nitrogen removal efficiency in a dyestuff wastewater treatment plant with the IFFAS process: the pilot-scale and full-scale studies

Water Science & Technology ◽

10.2166/wst.2017.522 ◽

2017 ◽

Vol 77 (1) ◽

pp. 70-78 ◽

Cited By ~ 4

Author(s):

Yanjun Mao ◽

Xie Quan ◽

Huimin Zhao ◽

Yaobin Zhang ◽

Shuo Chen ◽

...

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Removal Efficiency ◽

Nitrogen Removal ◽

Treatment Plant ◽

Oxygen Demand ◽

Pilot Scale ◽

Full Scale ◽

Nitrification And Denitrification ◽

Dyestuff Wastewater

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.

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