Abstract
To meet the effluent requirements given for the sensitive receiving body, the Southpest Wastewafer Treatment Plant of Budapest, Hungary uses a combined activated sludge-biofilter system with chemical precipitation for P removal. Causes of the proliferation of glycogen accumulating organisms (GAOs) observed in the unaerated/oxic activated sludge unit of this system were investigated both in full-scale and in lab-scale experiments combined with a detailed analysis of the microbial communities. Concentration profile measurements throughout the 8-stage activated sludge unit indicated anaerobic conditions in the first two unaerated reactors and low orthophosphate level (< 1 mg l-1) in all of the stages that could not be attributed to the influent quality, but to Fe (III)-dosing to the returned activated sludge. Microbiological analysis revealed the presence of GAOs from the GB group in the Gammaproteobacteria and occasionally tetrad-forming organisms from Actinobacteria, and the absence of Rhodocyclus-related polyphosphate accumulating organisms (PAOs) in the activated sludge samples. Comparative lab-scale studies carried out in two identically arranged UCT-systems with staged anoxic reactors also confirmed that Fe (III)-dosing may result in phosphorus deficiency of the microbial niche, leading to the suppression of growth and EBPR activity of PAOs and to the proliferation of GAOs.
Original language | English (US) |
---|---|
Pages (from-to) | 101-109 |
Number of pages | 9 |
Journal | Water Science and Technology |
Volume | 54 |
Issue number | 1 |
DOIs | |
State | Published - 2006 |
Externally published | Yes |
Keywords
- Activated sludge
- Chemical precipitation
- Glycogen accumulating organisms
- Phosphorus removal
- Polyphosphate accumulating organisms
ASJC Scopus subject areas
- Environmental Engineering
- Water Science and Technology