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The impact of reduced phosphorus levels on microbial floc properties during biological treatment of pulp and paper wastewaters.
- Source :
-
Water science and technology : a journal of the International Association on Water Pollution Research [Water Sci Technol] 2007; Vol. 55 (6), pp. 73-9. - Publication Year :
- 2007
-
Abstract
- The effect of limiting P in activated sludge was investigated in laboratory scale sequencing batch reactors (SBRs) fed effluent from a container board mill. Floc characterization included measurement of hydrophobicity, surface charge, and analysis of extracellular polymeric substances (EPS). Reactor performance was assessed by monitoring COD and inorganic P removal, MLSS, and sludge settleability (SVI and batch settling flux) over a period of eight months. Control reactors (BOD:N:P of 100:5:1) were compared to reactors run under P-limited conditions (100:5:0.3; 100:5:0.1). Reactor performance at lower temperatures (14 degrees C; control = 26 degrees C) was also studied to assess the impact of P-limitation. Changes in floc structure and the composition of EPS occurred within 1 to 3 days following a reduction in P levels. There was an insignificant increase in SVI; however, gravitational settling velocity and batch settling flux values for low P floc were consistently higher than for floc generated under control conditions. Lower temperatures (14 degrees C) resulted in a deterioration in floc settling properties at a BOD:N:P of 100:5:1. This impact on settling was significantly reduced at a BOD:P of 100:0.1. Reducing P concentrations in the wastewater treatment system has the potential to improve sludge settleability and reduce final P discharges.
Details
- Language :
- English
- ISSN :
- 0273-1223
- Volume :
- 55
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- Water science and technology : a journal of the International Association on Water Pollution Research
- Publication Type :
- Academic Journal
- Accession number :
- 17486837
- Full Text :
- https://doi.org/10.2166/wst.2007.214