Evaluation of combined chemical and biological nutrient removal

1996 ◽  
Vol 34 (1-2) ◽  
pp. 285-292 ◽  
Author(s):  
P. R. Thomas ◽  
D. Allen ◽  
D. L. McGregor
Keyword(s):  
Total Phosphorus ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Treatment Plant ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Minor Variation ◽  
Plant Trials ◽  
A Minor ◽  
Biological Phosphorus

This study was undertaken to optimise phosphorus removal by incorporating a chemical dosing facility in an existing biological nutrient removal activated sludge plant at Albury in Australia. Results of pilot plant trials and jar tests indicated that both alum and ferric chloride successfully reduced the orthophosphate concentrations with only a minor variation in the chemical costs. However, alum was chosen as the preferred chemical for use in the full-scale plant and tests showed that alum precipitation combined with biological nutrient removal lowered the orthophosphate (ortho-P) concentrations to as low as 0.01 mg/L with average total phosphorus (total-P) levels of around 0.5 mg/L. It is concluded that maximising total phosphorus removal in the treatment plant would require optimising biological phosphorus removal, applying correct chemical dosages to varying mixed liquor orthophosphate concentrations, adequate mixing, suitable pH values and minimising suspended solids in the clarifier effluent.

Practical Experience with Biological Phosphorus Removal Plants in Johannesburg

1983 ◽  
Vol 15 (3-4) ◽  
pp. 233-259 ◽  
Author(s):  
A R Pitman ◽  
S L V Venter ◽  
H A Nicholls
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Operating Experience ◽  
Practical Experience ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Factors Affecting ◽  
Process Improvements ◽  
Biological Phosphorus

This paper describes three years operating experience with two full-scale biological nutrient removal activated sludge plants. Factors affecting biological phosphorus removal are highlighted and possible process improvements suggested.

Comparison of nutrient removal efficiency between pre- and post-denitrification wastewater treatments

2006 ◽  
Vol 53 (9) ◽  
pp. 169-175 ◽  
Author(s):  
K. Hamada ◽  
T. Kuba ◽  
V. Torrico ◽  
M. Okazaki ◽  
T. Kusuda
Keyword(s):  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Nutrient Removal Efficiency ◽  
Polyphosphate Accumulating Organisms ◽  
Biological Phosphorus ◽  
Denitrification Process

A shortage of organic substances (COD) may cause problems for biological nutrient removal, that is, lower influent COD concentration leads to lower nutrient removal rates. Biological phosphorus removal and denitrification are reactions in which COD is indispensable. As for biological simultaneous nitrogen and phosphorus removal systems, a competition problem of COD utilisation between polyphosphate accumulating organisms (PAOs) and non-polyphosphate-accumulating denitrifiers is not avoided. From the viewpoint of effective utilisation of limited influent COD, denitrifying phosphorus-removing organisms (DN-PAOs) can be effective. In this study, DN-PAOs activities in modified UCT (pre-denitrification process) and DEPHANOX (post-denitrification ptocess) wastewater treatments were compared. In conclusion, the post-denitrification systems can use influent COD more effectively and have higher nutrient removal efficiencies than the conventional pre-denitrification systems.

Simultaneous removal of organic and strong nitrogen from sewage in a pilot-scale BNR process supplemented with food waste

2004 ◽  
Vol 49 (5-6) ◽  
pp. 257-264 ◽  
Author(s):  
S.R. Chae ◽  
S.H. Lee ◽  
J.O. Kim ◽  
B.C. Paik ◽  
Y.C. Song ◽  
...  
Keyword(s):  
Carbon Source ◽  
Food Waste ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Pilot Scale ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
External Carbon Source ◽  
N Removal ◽  
Biological Phosphorus

As the sewerage system is incomplete, sewage in Korea lacks easily biodegradable organics for nutrient removal. In this country, about 11,400 tons of food waste of high organic materials is produced daily. Therefore, the potential of food waste as an external carbon source was examined in a pilot-scale BNR (biological nutrient removal) process for a half year. It was found that as the supply of the external carbon increased, the average removal efficiencies of T-N (total nitrogen) and T-P (total phosphorus) increased from 53% and 55% to 97% and 93%, respectively. VFAs (volatile fatty acids) concentration of the external carbon source strongly affected denitrification efficiency and EBPR (enhanced biological phosphorus removal) activity. Biological phosphorus removal was increased to 93% when T-N removal efficiency increased from 78% to 97%. In this study, several kinds of PHAs (poly-hydroxyalkanoates) in cells were observed. The observed PHAs was composed of 37% 3HB (poly-3- hydroxybutyrate), 47% 3HV (poly-3-hydroxyvalerate), 9% 3HH (poly-3-hydroxyhexanoate), 5% 3HO (poly-3-hydroxyoctanoate), and 2% 3HD (poly-3-hydroxydecanoate).

Effects of injection of acetic acid and propionic acid for total phosphorus removal at high temperature in enhanced biological phosphorus removal process

2014 ◽  
Vol 69 (10) ◽  
pp. 2023-2028 ◽  
Author(s):  
C. Y. Ki ◽  
K. H. Kwon ◽  
S. W. Kim ◽  
K. S. Min ◽  
T. U. Lee ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Source ◽  
Removal Efficiency ◽  
Total Phosphorus ◽  
Phosphorus Removal ◽  
Treatment Plant ◽  
Biological Phosphorus Removal ◽  
External Carbon Source ◽  
Removal Process ◽  
Biological Phosphorus

In summer, wastewater treatment plant total phosphorus (TP) removal efficiency is low in South Korea. The reason is because of high temperatures or significant fluctuation of inflow characteristics caused by frequent rainfall. Hence, this study tried to raise TP removal efficiency by injecting fixed external carbon sources in real sewage. Polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) compete to occupy microorganisms at high temperature. Propionate is known to restrain GAOs. Thus, acetate and propionate were chosen as the external carbon source in this study to find out the suitable volume and ratio of carbon source which ensured the dominance of PAOs. An external carbon source was supplied in the anaerobic reactor of the biological phosphorus removal process at high temperature (above 25 °C). TP removal efficiency was improved by injecting an external carbon source compared to that without an external carbon source. Also, it remained relatively stable when injecting an external carbon source, despite the variation in temperature. TP removal efficiency was the highest when injecting acetate and propionate in the proportion of 2:1 (total concentration as chemical oxygen demand (COD) is 12 mg/L in influent).

Temperature effects on biological nutrient removal system with weak municipal wastewater

1998 ◽  
Vol 37 (9) ◽  
pp. 219-226 ◽  
Author(s):  
Choi Euiso ◽  
Rhu Daewhan ◽  
Yun Zuwhan ◽  
Lee Euisin
Keyword(s):  
Low Temperature ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Temperature Effects ◽  
Municipal Wastewater ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Removal Efficiencies ◽  
Biological Phosphorus ◽  
Operating Result

The wastewater characteristics of low organic strength coupled with low temperature would be considerable variables for design and operation of biological nutrient removal (BNR) systems. But temperature studies have mostly been focused on individual process with biological phosphorus removal, nitrification and denitrification, respectively. Overall temperature effects on BNR system may not be fully represented by sum of results of separated studies on biological nutrient removal steps. The operating result of a retrofitted full scale unit along with laboratory-scale BNR unit indicated 90% of nitrification was possible at temperature as low as 8°C. However, the denitrification was turned out to be a key step to regulate the overall nutrient removal efficiencies. When the operating temperature dropped down, a rapid decrease of phosphorus removal efficiencies was observed by the nitrate in return sludge. If nitrification was not well developed, phosphorus removal returned to the normal efficiency even at low temperature of 5°C. The phosphorus removal mechanism was not influenced at this low temperature.

Retrofit of biological nutrient removal process assisted by numerical simulation with activated sludge model no. 2

1996 ◽  
Vol 34 (1-2) ◽  
pp. 221-228 ◽  
Author(s):  
Gakuji Kurata ◽  
Kazushi Tsumura ◽  
Syoichiro Nakamura ◽  
Michio Kuwahara ◽  
Akio Sato ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Biological Nutrient Removal ◽  
Organic Substrates ◽  
Biological Phosphorus Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Removal Process ◽  
Biological Phosphorus

In existing wastewater treatment plants that employ biological nitrogen and phosphorus removal processes, a low concentration of organic substrates in the influent wastewater has a destabilizing effect on the phosphorus removal process. Many efforts have been made to combat this problem, including reconstructing the process flow and improving operation and control systems. However, because the mechanism used for biological phosphorus removal is complex, it is difficult to establish effective empirical methods. For this paper, we constructed a simulator for the wastewater treatment process and tried to improve on current procedures, focusing on the planning, execution, and evaluation of methods of retrofitting existing WWTP with equipment for biological nutrient removal. The Shinnanyo WWTP uses the anaerobic/aerobic activated sludge process to remove nitrogen and phosphorus biologically. At this plant, however, the influent wastwwater has an insufficient concentration of organic substrates, thus decreasing the efficiency of the biological phosphorus removal. An analysis of organic consumption in the reaction tank on the simulation suggested that injecting primary sludge into the reaction tank would increase the efficiency of phosphorus removal process. Full scale experiments conducted at the plant verified the efficiency of this method. In addition, by shortening the A-SRT, ensuring that nitrification is not negatively affected, the efficiency of the nitrogen and phosphorus removal was significantly improved.

Design Considerations for Nutrient Removal Activated Sludge Plants

1991 ◽  
Vol 23 (4-6) ◽  
pp. 781-790 ◽  
Author(s):  
A. R. Pitman
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Phosphorus Removal ◽  
Full Scale ◽  
Biological Nutrient Removal ◽  
Biological Phosphorus Removal ◽  
Anoxic Zone ◽  
Mixed Liquor ◽  
Design Considerations ◽  
Biological Phosphorus

Based on more than 10 years' experience with biological nutrient removal in Johannesburg, this paper highlights aspects which should be borne in mind in the design of such processes. Feed sewage quality and the question of treating raw or settled sewage are considered. More importantly, methods of rendering the feed more suitable for biological phosphorus removal are detailed. As nitrate feedback to the anaerobic zone can often mitigate against good phosphorus removal, methods of obviating this are covered. In this respect the need for, and placement of a second anoxic zone are discussed. Process type and configuration are covered as well as zone retention periods and the split of process volume into unaerated and aerated fractions. Aeration systems and the tailoring of aeration to process needs are also discussed. Two problems that have been experienced in many full-scale plants are bulking sludges and prolific growths of nuisance scums. Methods of minimising these problems are discussed. Finally, mixed liquor and return sludge recycles; aspects to be borne in mind in the design of final clarifiers and the provision of standby chemical addition are discussed.

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