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Biological phosphorus removal at temperatures from 3-degrees-c to 10-degrees-c - a full-scale study of a sequencing batch reactor unit
1994 (English)In: Canadian journal of civil engineering (Print), ISSN 0315-1468, Vol. 21, no 1, 81-88 p.Article in journal (Refereed) Published
Abstract [en]

Low temperature biological phosphorus removal technology was tested at a small village wastewater treatment plant near the Arctic circle. An aeration basin in a conventional activated sludge step was retrofitted to a sequencing batch reactor with a maximum volume of approximately 27 m3. The study period was November 1989 to June 1991. The wastewater temperature varied between 3 and 10-degrees-C during one full year and was below 5-degrees-C during approximately 240 days of the year. A total sequencing batch reactor cycle time of 6-12 hours produced a phosphorus reduction of 70-80%. During the same time, biochemical oxygen demand (BOD7) reductions varied between 70% and 90%. These reductions were achieved at supernatant suspended solid concentrations of 20-30 mg/L. Effluent soluble phosphorus concentrations were usually lower than 1.0 mg/L at water temperatures down to 5-degrees-C. At 4-degrees-C, a sharp increase to greater than 2.0 mg/L was evident. Supernatant soluble BOD7 was less than 8 mg/L and was found to be independent of temperature.

Place, publisher, year, edition, pages
1994. Vol. 21, no 1, 81-88 p.
Keyword [en]
biological waste-water phosphorus removal, sequencing batch reactor, cold climate
National Category
Other Environmental Engineering Water Engineering
URN: urn:nbn:se:kth:diva-14320ISI: A1994NC25500008OAI: diva2:332218
QC 20100803Available from: 2010-08-03 Created: 2010-08-03 Last updated: 2010-08-03Bibliographically approved
In thesis
1. SBR-technology - use and potential applications for treatment of cold wastewater
Open this publication in new window or tab >>SBR-technology - use and potential applications for treatment of cold wastewater
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Biological nutrient removal is used as an indicator of SBR performance at nine different SBRplants operated for a long period at low water temperatures (5 – 10oC). Typically needed aeratedSRT (Solids Residence Time) for complete nitrification is found to be in the range of 6 – 10 days.Biological phosphorus removal has been found to take place at 5oC.

The specific nitrification and denitrification rates (g N/kg VSS/h) have been found to besubstantially higher than those found in design recommendations. At temperatures < 10 oC thenitrification rates have been found up to 4 g Nox/kg VSS/h.

It has also been possible to establish a relation between the COD/N ratio and the nitrificationrate, showing that the rate increases to high rates when the ratio decreases.

Enhanced biological phosphorus removal has been demonstrated at two different plants even atlow water temperatures 5 – 7 oC.

Efficient biological nitrogen removal and phosphorus removal has been demonstrated at bothlow water temperatures and in presence of very high Chromium concentrations in inlet water, upto 20 mg Cr/l.

The plants operated with a short fill time in comparison with the total cycle time for the SBRprocess have all demonstrated good sludge settling properties, suggesting that the SBR processmay incorporate a good sludge selection performance.

Once a flexible operation strategy has been installed (in most cases through PLC systems) it hasbeen possible to meet load variations to maintain good treatment results. This has been found tobe true for most of the plants included in the thesis.

Finally, a modified way to assess the energy efficiency for the system is analysed and suggested.Instead of using the traditional ratio kWh/kg BODremoved the use of kWh/kg OCPremoved as a basisfor energy efficiency is used as a far more relevant efficiency measurement.

Place, publisher, year, edition, pages
Stockholm: KTH, 2009. xviii, 63 p.
Trita-LWR. PHD, ISSN 1650-8602 ; 1050
Intermittent operation, Water temperature, nitrogen, phosphorus, SBR, reaction rates
National Category
Other Environmental Engineering
urn:nbn:se:kth:diva-10550 (URN)978-91-7514-341-5 (ISBN)
Public defence
2009-06-03, Sal F3, Lindstedtsvägen 26, KTH, Stockholm, 10:00 (English)
QC 20100803Available from: 2009-05-26 Created: 2009-05-26 Last updated: 2010-08-03Bibliographically approved

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