Cold climate sequencing batch reactor biological phosphorus removal: results 1991-92
1993 (English)In: Proceedings of the 2nd International Conference on Design and Operation of Small Wastewater Treatment Plants / [ed] H. Ødegaard, Oxford: Pergamon Press, 1993, 275-282 p.Conference paper (Refereed)
The aeration tank in a small scale wastewater treatment plant was converted to a sequencing batch reactor (SBR) with a maximum volume of approx. 27 m super(3). The main purpose of this study was to examine low temperature biological phosphorous removal (BPR). The wastewater temperature varied during the study between 3 and 8 degree C, with a water temperature at or below 5 degree C during seven months of the year. The SBR unit has been in operation from the end of 1989, the study period discussed here covered July 1991 - December 1992. SBR cycle time was varied between 6 and 12 hours, giving a total daily treatment capacity of between 18 and 36 m super(3). The influent biological oxygen demand - 7 days (BOD sub(7)) levels varied between 88 and 165 mg/l. Corresponding phosphorous levels were between 3.10 and 9.55 mg/l. The mean efficient level of phosphorous was 1.57 mg/l and the B)D sub(7) was 23 mg/l. This gives a mean total phosphorous reduction of 74% and a BOD sub(7) reduction of 81%. During the study, mean supernatant suspended solids (SS) levels were quite high at around 36 mg/l. This high SS level contributed a major part of both outlet phosphorous as well as BOD sub(7) value. Effluent soluble values for phosphorous and BOD sub(7) were 0.79 mg/l and 9 mg/l. The supernatant SS component of BOD sub(7) and phosphorous increased at lower temperatures. It was not possible to reduce or balance this increase by increased cycle time or increased settling time within the maximum cycle time available (12 hours). Stable low supernatant phosphorous and BOD sub(7) levels are thus to a large degree controlled by the effluent SS level. A maximum of 20 mg/l supernatant SS is necessary to reach target supernatant values of less than 1 mg/l of phosphorous and 15 mg/l of BOD sub(7).
Place, publisher, year, edition, pages
Oxford: Pergamon Press, 1993. 275-282 p.
Water Science and Technology, ISSN 0273-1223 ; 28:10
Research subject Urban Water Engineering
IdentifiersURN: urn:nbn:se:ltu:diva-37068Local ID: af29c350-3e27-11de-bf5b-000ea68e967bOAI: oai:DiVA.org:ltu-37068DiVA: diva2:1010566
International Conference on Design and Operation of Small Wastewater Treatment Plants : 28/06/1993 - 30/06/1993
Godkänd; 1993; 20090511 (andbra)2016-10-032016-10-03Bibliographically approved