Denitrificiation in a Non-Nitrifying Activated Sludge System

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1097-1104 ◽  
Author(s):  
A. Lyngå ◽  
P. Balmér
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Nitrogen Removal ◽  
Cost Effective ◽  
Pilot Scale ◽  
Anoxic Zone ◽  
Sludge Treatment ◽  
Activated Sludge System ◽  
Cost Effective Method ◽  
Nitrate Supply

Post-nitrification and recycling of the nitrified effluent to an anoxic zone in an activated sludge system for denitrification is proposed as a potentially cost-effective method for nitrogen removal in existing activated sludge treatment plants. Denitrification in a non-nitrifying activated sludge system with a SRT of 3-4 days has been studied in pilot scale. The results show that denitrification rates of at least 10 g N03-N/(kgVSS h) can be achieved. At COD/NO3-N ratios above 15, nitrate supply appears to control the denitrification rate while at COD/NO3-N ratios below 15 the rate appears to be controlled by the supply of easily biodegradable organic matter.

Internal recycle to improve denitrification in a step feed anoxic/aerobic activated sludge system

2009 ◽  
Vol 60 (7) ◽  
pp. 1661-1668 ◽  
Author(s):  
C. A. Boyle ◽  
C. J. McKenzie ◽  
S. Morgan
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Anoxic Zone ◽  
Activated Sludge System ◽  
Low Load ◽  
Aerobic Zone ◽  
Wastewater Treatment Plant Effluent

During periods of low load (weekends and holidays) the Mangere wastewater treatment plant effluent has breached the summer consent conditions for total nitrogen. The purpose of this research was to determine if an internal recycle would improve nitrogen removal in the anoxic/aerobic activated sludge reactors sufficient to meet the summer resource consent standard. The recycle returned nitrate rich mixed liquor from the downstream aerobic zone back to the initial anoxic zone, thus potentially improving denitrification. A full scale trial showed that installation of the internal recycle on each RC would have satisfied the resource consent for total nitrogen in most cases over the three summer resource consent periods since the upgrade. However, further modifications of the internal recycle would be required to ensure that consent conditions were satisfied at all times and to improve the consistency of the results.

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

2017 ◽  
Vol 77 (1) ◽  
pp. 70-78 ◽  
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.

scholarly journals Cost Effective Method for Toxicity Screening of Pharmaceutical Wastewater Containing Inorganic Salts and Harmful Organic Compounds

2019 ◽  
Vol 23 (1) ◽  
pp. 52-63 ◽  
Author(s):  
Elina Strade ◽  
Daina Kalnina
Keyword(s):  
Activated Sludge ◽  
Biological Treatment ◽  
Oxygen Demand ◽  
Cost Effective ◽  
Practical Implementation ◽  
Toxicity Screening ◽  
Pharmaceutical Wastewater ◽  
Cost Effective Method ◽  
Wide Range ◽  
Wastewater Biological Treatment

Abstract Pharmaceutical wastewater biological treatment plants are stressed with multi-component wastewater and unexpected variations in wastewater flow, composition and toxicity. To avoid operational problems and reduced wastewater treatment efficiency, accurate monitoring of influent toxicity on activated sludge microorganisms is essential. This paper outlines how to predict highly toxic streams, which should be avoided, using measurements of biochemical oxygen demand (BOD), if they are made in a wide range of initial concentration. The results indicated that wastewater containing multivalent Al3+ cations showed a strong toxic effect on activated sludge biocenosis irrespectively of dilutions, while toxicity of phenol and formaldehyde containing wastewater decreased considerably with increasing dilution. Activated sludge microorganisms were not sensitive to wastewater containing halogenated sodium salts (NaCl, NaF) and showed high treatment capacity of saline wastewater. Our findings confirm that combined indicators of contamination, such as chemical oxygen demand (COD), alone do not allow evaluating potential toxic influence of wastewater. Obtained results allow identifying key inhibitory substances in pharmaceutical wastewater and evaluating potential impact of new wastewater streams or increased loading on biological treatment system. Proposed method is sensitive and cost effective and has potential for practical implementation in multiproduct pharmaceutical wastewater biological treatment plants.

Fate of selected RCRA compounds in a pilot-scale activated sludge system

1996 ◽  
Vol 68 (3) ◽  
pp. 260-269 ◽  
Author(s):  
S. K. Bhattacharya ◽  
R. L. Madura ◽  
R. A. Dobbs ◽  
R. V. R. Angara ◽  
H. Tabak
Keyword(s):  
Activated Sludge ◽  
Pilot Scale ◽  
Activated Sludge System
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