Performance and Operational Aspects of Biological Phosphate Removal Plants in South Africa

1983 ◽  
Vol 15 (3-4) ◽  
pp. 219-232 ◽  
Author(s):  
B H Paepcke
Keyword(s):  
South Africa ◽  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Nitrogen Concentration ◽  
Air Entrainment ◽  
Phosphate Removal ◽  
Plant Performance ◽  
Nitrogen And Phosphorus ◽  
Multi Stage

A survey was undertaken of the operation and performance of eleven multi-stage activated sludge plants in South Africa designed for biological nitrogen and phosphorus removal. The results indicate that phosphorus removal has been consistently good in only one case, although several other plants have performed very well in recent months. The major factors adversely affecting phosphorus removal are excessive amounts of nitrate and dissolved oxygen in the anaerobic basins. Nitrate is introduced into the anaerobic basin in the return activated sludge when denitrification is incomplete. Incomplete denitrification is due to a disproportionately low amount of carbonaceous matter in the influent wastewater relative to the total nitrogen concentration. The dissolved oxygen is the result of air entrainment at the Archimedes screw return activated sludge pumps, at cascades in the influent and return sludge channels, and by vortices caused by the stirrers. Other factors which have significantly affected plant performance are mechanical problems, inadequate operator training, and insufficient sample analyses on which to base operating decisions. With due recognition paid to these problem areas, the performance of future designs should be much improved.

Improved Biological Phosphorus Removal Resulting from the Enrichment of Reactor Feed with Fermentation Products

1992 ◽  
Vol 26 (5-6) ◽  
pp. 943-953 ◽  
Author(s):  
L. H. Lötter ◽  
A. R. Pitman
Keyword(s):  
South Africa ◽  
Fatty Acids ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Volatile Fatty Acids ◽  
Phosphate Removal ◽  
Biodegradable Materials ◽  
Biological Phosphorus Removal ◽  
Fermentation Products ◽  
Biological Phosphorus

Research in South Africa has highlighted the dependence of biological phosphate removal mechanisms on the presence of certain minimum concentrations of some readily biodegradable materials including interalia volatile fatty acids. Successful generation of these compounds has been achieved at recently commissioned facilities at three of Johannesburg' activated sludge plants. Elutriation of the volatile fatty acids from the sludge was achieved by recycling sludge to the influent sewage stream. Significant improvements in phosphate removal were observed, thus reducing the demand for chemical dosing to achieve the phosphate standard. In this paper the effect of altering the feed sewage characteristics on biological phosphorus removal is discussed.

Extension of the Seehausen Sewage Works to Meet the New Requirements on Nitrogen and Phosphorus Removal

1992 ◽  
Vol 25 (4-5) ◽  
pp. 43-50
Author(s):  
G. Ermel ◽  
A. Mennerich ◽  
G. Höper
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Maximum Flow ◽  
Weather Conditions ◽  
Phosphate Removal ◽  
Biological Phosphorus Removal ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Two Stage ◽  
The North

At the Seehausen Sewage Works, the sewage arising from the City of Bremen is treated. The maximum dry weather sewage flow is about 150,000 m3/d; under storm weather conditions the maximum flow is 300,000 m3/d. The existing plant consists of a primary sedimentation followed by a two stage activated sludge plant. Waste sludge is treated in 5 anaerobic digesters followed by dewatering centrifuges. At present, the plant achieves full removal of the BOD5, however no nitrification. In accordance with the new German water laws and with respect to the eutrophication problems encountered in the North Sea, both nitrogen and phosphorus removal are required in the future. This paper describes the measures planned to enlarge the volume of the activated sludge plant for nitrification/denitrification and measures for biological phosphate removal by means of anaerobic basins. A new single stage activated sludge plant for 50% of the total sewage flow will be built. After completion of this plant, it will be operated in parallel with the existing two stage plant. Both, the old and the new part of the plant, will provide nitrification and denitrification. In addition, the new plant is designed for biological phosphorus removal. The existing secondary clarifiers will be connected to both plants at 50% each.

Nitrogen and Phosphorus Removal by Activated Sludge Process: A Review

2017 ◽  
Vol 14 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Zhengan Zhang ◽  
Shulin Pan ◽  
Fei Huang ◽  
Xiang Li ◽  
Juanfang Shang ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal

New German design guideline for single stage activated sludge plants

2000 ◽  
Vol 41 (9) ◽  
pp. 139-145
Author(s):  
R. Kayser
Keyword(s):  
Activated Sludge ◽  
Phosphorus Removal ◽  
Design Procedure ◽  
Single Stage ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Design Guideline

The German design guideline A 131 “Design of single stage activated sludge plants” was amended in 1999. The main changes of the guideline from 1991 are outlined. The design procedure for plants with nitrogen and phosphorus removal is presented.

Evolution of the Southpest Wastewater Treatment Plant

2000 ◽  
Vol 41 (9) ◽  
pp. 7-14
Author(s):  
A. Jobbágy ◽  
B. Literáthy ◽  
F. Farkas ◽  
Gy. Garai ◽  
Gy. Kovács
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Phosphorus Removal ◽  
Treatment Plant ◽  
Low Flow ◽  
Nitrate Content ◽  
Nitrogen And Phosphorus ◽  
Treated Effluent ◽  
Processing Wastes

The treated effluent of the Southpest Wastewater Treatment Plant is discharged into a small, low-flow branch of the Danube susceptible to eutrophication. The first, high-load activated sludge system with a hydraulic retention time of 2.5 hrs in the aerated basins, was installed here in 1966. The paper presents the evolution of the technology by illustrating the effects of the different changes carried out since 1991. Reconfiguration of the existing activated sludge basins connected originally in parallel into an arrangement of tanks in series increased the settleability of the sludge as well as the efficiency of COD removal significantly. Introduction of an anaerobic zone preceding the aerated basins facilitated biological excess phosphorus removal with a consequent release in the thickener and digester. Introducing lime addition into the recycled sludge processing wastes significantly improved the performance of the system. However, since there had been no provision built for eliminating the nitrate content of the recycled sludge, efficiency of phosphorus removal proved to be dependent on the eventually occurring nitrification. In order to achieve both an effective nitrogen and phosphorus removal the current technology established in 1999 applies a nitrification and a denitrification filter following the activated sludge unit and uses precipitation for phosphorus removal.

The Influence of Nitrogen on Phosphorus Removal in Activated Sludge Plants

1982 ◽  
Vol 14 (1-2) ◽  
pp. 31-45 ◽  
Author(s):  
J L Barnard
Keyword(s):  
Organic Carbon ◽  
Activated Sludge ◽  
Phosphorus Removal ◽  
Complete Removal ◽  
Phosphate Removal ◽  
Electron Donors ◽  
Biological Phosphorus Removal ◽  
Anaerobic Conditions ◽  
Low Level ◽  
Biological Phosphorus

This paper discusses the need for anaerobiases as a pre-requisite for phosphorus removal in activated sludge plants and the effect of nitrates on the anaerobic conditions. If the plant could be operated to avoid nitrification, biological phosphorus removal presents no problems. When nitrification is required, the nitrates must be reduced to a low level through internal denitrification. If sufficient carbon is available to ensure complete removal of the nitrates and anaerobic conditions in a specific zone in the plant, good phosphate removal can be ensured. Below COD : TKN ratios of 10 : 1 it is becoming more difficult to control the plant and special care should be taken to determine not only the quantity of organic carbon available as electron donors for removal of the nitrates but also the form in which it arrives at the plant.

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