Effects of root exudates on rhizosphere bacteria and nutrient removal in pond-ditch circulation systems (PDCSs) for rural wastewater treatment

A brief review of recent developments in biological nitrogen and phosphorus removal technology is presented. Guidelines are outlined of how current understanding of these two removal mechanisms can be applied in the upgrading of existing wastewater treatment plants for biological nutrient removal. A case history dealing with the upgrading of the conventional activated sludge process located at Penticton, British Columbia, to a biological nutrient removal facility with a design flow of 18,200 m3/day (4.0 IMGD) is presented as a design example. Process components requiring major modification were the headworks, bioreactors and sludge handling facilities.

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Nutrient Removal in Small Wastewater Treatment Plants

Water Science & Technology ◽

10.2166/wst.1990.0203 ◽

1990 ◽

Vol 22 (3-4) ◽

pp. 211-216

Author(s):

Niels Skov Olesen

Keyword(s):

Wastewater Treatment ◽

Nitrogen Removal ◽

Nutrient Removal ◽

Phosphorus Removal ◽

Wastewater Treatment Plants ◽

Ferrous Sulphate ◽

Practical Solution ◽

Sensitive Technique ◽

Pumping Station ◽

Denitrification Reactor

In some areas of Denmark nutrient removal is required even for very small wastewater plants, that is down to 500 pe (pe = person equivalents). The goal for the removal is 80% removal of nitrogen and 90% removal of phosphorus, or in terms of concentrations: 8 mg nitrogen/l and 1.2 mg phosphorus/l. The inlet concentrations are typically 40 mg N/l and 10 mg P/l. The paper presents the results from two such plants with a capacity of 800 pe. Phosphorus removal is made by simultaneous precipitation with ferrous sulphate. Nitrogen removal is carried out using the recirculation method. Both plants were originally rotor aerated oxidation ditches. They have been extended with a denitrification reactor and a recirculation pumping station. At present both plants have been in activity for about 3 years and with satisfactory results. Average concentrations of nitrogen (summer) and phosphorus is 7 mg/l and 0.9 mg/l respectively. Nitrogen removal seems to be a practical solution on these small plants. It is,though, sensitive to temperature and highly oxidized rain water. Phosphorus removal seems to be an easily run and relatively non-sensitive technique at least when using simultaneous precipitation.

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Experience with nutrient removal in a fixed-film system at full-scale wastewater treatment plants

Water Science & Technology ◽

10.2166/wst.1997.0030 ◽

1997 ◽

Vol 36 (1) ◽

pp. 129-137 ◽

Cited By ~ 7

Author(s):

Vibeke R. Borregaard

Keyword(s):

Wastewater Treatment ◽

Surface Area ◽

Nutrient Removal ◽

Wastewater Treatment Plants ◽

High Specific Surface Area ◽

Biological Nutrient Removal ◽

Growth Processes ◽

Total N ◽

Attached Growth ◽

On Line

In the upgrade of wastewater treatment plants to include biological nutrient removal the space available is often a limiting facor. It may be difficult to use conventional suspended growth processes (i.e. activated sludge) owing to the relatively large surface area required for these processes. Recent years have therefore seen a revived interest in treatment technologies using various types of attached growth processes. The “new” attached growth processes, like the Biostyr process, utilise various kinds of manufactured media, e.g. polystyrene granules, which offer a high specific surface area, and are therefore very compact. The Biostyr plants allow a combination of nitrification-denitrification and filtration in one and the same unit. The results obtained are 8 mg total N/l and an SS content normally below 10 mg/l. The plants in Denmark which have been extended with a Biostyr unit have various levels of PLC control and on-line instrumentation.

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