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Phosphorus Removal (phosphorus + removal)

Distribution by Scientific Domains
Life Sciences30%

Kinds of Phosphorus Removal

  • biological phosphorus removal
    		•

    Selected Abstracts

    Ecophysiology of a group of uncultured Gammaproteobacterial glycogen-accumulating organisms in full-scale enhanced biological phosphorus removal wastewater treatment plants

    ENVIRONMENTAL MICROBIOLOGY, Issue 3 2006
    Yunhong Kong
    Summary The presence of glycogen-accumulating organisms (GAOs) in enhanced biological phosphorus removal (EBPR) plants can seriously deteriorate the biological P-removal by out-competing the polyphosphate-accumulating organisms (PAOs). In this study, uncultured putative GAOs (the GB group, belonging to the Gammaproteobacteria) were investigated in detail in 12 full-scale EBPR plants. Fluorescence in situ hybridization (FISH) revealed that the biovolume of the GB bacteria constituted 2,6% of total bacterial biovolume. At least six different subgroups of the GB bacteria were found, and the number of dominant subgroups present in each plant varied between one and five. Ecophysiological investigations using microautoradiography in combination with FISH showed that, under aerobic or anaerobic conditions, all subgroups of the GB bacteria could take up acetate, pyruvate, propionate and some amino acids, while some subgroups in addition could take up formate and thymidine. Glucose, ethanol, butyrate and several other organic substrates were not taken up. Glycolysis was essential for the anaerobic uptake of organic substrates. Polyhydroxyalkanoates (PHA) but not polyphosphate (polyP) granules were detected in all GB bacterial cells. Polyhydroxyalkanoate formation after anaerobic uptake of acetate was confirmed by measuring the increase in fluorescence intensity of PHA granules inside GB bacterial cells after Nile blue staining. One GB subgroup was possibly able to denitrify, and several others were able to reduce nitrate to nitrite. PAOs were also enumerated by FISH in the same treatment plants. Rhodocyclus -related PAOs and Actinobacteria -related PAOs constituted up to 7% and 29% of total bacterial biovolume respectively. Rhodocyclus -related PAOs always coexisted with the GB bacteria and showed many physiological similarities. Factors of importance for the competition between the three groups of important bacteria in EBPR plants are discussed. [source]

    Which are the polyphosphate accumulating organisms in full-scale activated sludge enhanced biological phosphate removal systems in Australia?

    JOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2006
    M. Beer
    Abstract Aims:, To see if the compositions of the microbial communities in full scale enhanced biological phosphorus removal activated sludge systems were the same as those from laboratory scale sequencing batch reactors fed a synthetic sewage. Methods:, Biomass samples taken from nine full scale enhanced biological phosphate removal (EBPR) activated sludge plants in the eastern states of Australia were analysed for their populations of polyphosphate (polyP)-accumulating organisms (PAO) using semi-quantitative fluorescence in situ hybridization (FISH) in combination with DAPI (4,-6-diamidino-2-phenylindole) staining for polyP. Results:, Very few betaproteobacterial Rhodocyclus related organisms could be detected by FISH in most of the plants examined, and even where present, not all these cells even within a single cluster, stained positively for polyP with DAPI. In some plants in samples from aerobic reactors the Actinobacteria dominated populations containing polyP. Conclusions:, The PAO populations in full-scale EBPR systems often differ to those seen in laboratory scale reactors fed artificial sewage, and Rhodocyclus related organisms, dominating these latter communities may not be as important in full-scale systems. Instead Actinobacteria may be the major PAO. Significance and Impact of the Study:, These findings illustrate how little is still known about the microbial ecology of EBPR processes and that more emphasis should now be placed on analysis of full-scale plants if microbiological methods are to be applied to monitoring their performances. [source]

    The beneficial role of intermediate clarification in a novel MBR based process for biological nitrogen and phosphorus removal

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2009
    MinGu Kim
    Abstract BACKGROUND: A novel membrane bioreactor (MBR) is described, employing an intermediate clarifier. Unlike the established function of a final clarifier in a conventional biological nutrient removal system, the role of an intermediate clarifier has rarely been studied. Thus, this work focused on explaining the fate of nutrients in the intermediate clarifier, as influenced by the hydraulic retention time (HRT) of the preceding anaerobic bioreactor. RESULTS: The system was tested with two different anaerobic/anoxic/aerobic biomass fractions of 0.25/0.25/0.5 (run 1) and 0.15/0.35/0.45 (run 2) using synthetic wastewater. The major findings of the study were that phosphorus (P) removal was affected by the role of the intermediate clarifier. In run 1, P was removed at a rate 0.16 g d,1 in the intermediate clarifier while in run 2, additional P was released at 0.49 g d,1. The nitrogen (N) removal efficiencies were 74 and 75% for runs 1 and 2 respectively, while P removal was 91 and 96%. P uptake by denitrifying phosphate accumulating organisms (DPAOs) accounted for 41,52% of the total uptake in the MBR. CONCLUSIONS: This study found that the intermediate clarifier assisted chemical oxygen demand (COD), N, and P removal. With respect to the fate of P, the intermediate clarifier functioned as an extended anaerobic zone when the HRT of the preceding anaerobic zone was insufficient for P release, and as a pre-anoxic zone when the anaerobic HRT was adequate for P release. Copyright © 2008 Society of Chemical Industry [source]

    Effects of influent C/N ratio, C/P ratio and volumetric exchange ratio on biological phosphorus removal in UniFed SBR process

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2008
    Chen-hong Zhao
    Abstract BACKGROUND: UniFed SBR is a novel process that can achieve high levels of nitrogen and phosphorus removal simultaneously in a simple single SBR tank. In this study, effects of influent C/N ratio, influent C/P ratio and volumetric exchange ratio on biological phosphorus removal in UniFed SBR process were investigated in a lab-scale UniFed apparatus treating real domestic wastewater. RESULTS: The results showed that phosphorus removal efficiency increased as C/N ratio increased from 27% at 2.8 to 88% at 5.7. For C/N ratios 6.5 and above, complete phosphorus removal could be achieved. When C/N ratios and volumetric exchange ratio were fixed at 6 and 33%, respectively, phosphorus removal efficiency remained at 100% for C/P ratios higher than 33; effluent phosphate concentration was below the detection limit. For C/P ratios lower than 33, phosphorus removal efficiency decreased linearly with C/P ratio. Under the same influent C/N ratio and C/P ratio, the following factors all contributed to better phosphorus removal performance: greater volumetric exchange ratio; more organic substrate for PAOs to utilize, less inhibition by NOx, of phosphorus release during the feed/decant period; more PHB synthesized; and more aerobic phosphate uptake. CONCLUSION: High influent C/N ratio, high C/P ratio and high volumetric exchange ratio were beneficial to phosphorus removal in this process. Copyright © 2008 Society of Chemical Industry [source]

    Effect of changes of pH on the anaerobic/aerobic transformations of biological phosphorus removal in wastewater fed with a mixture of propionic and acetic acids

    JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2006
    Yinguang Chen
    Abstract Most studies on the transformation of enhanced biological phosphorus removal have used acetic acid as the carbon source and focused on the anaerobic phase. In this paper the anaerobic and aerobic transformations of phosphorus removal microorganisms at various pH values were investigated with wastewater containing 3.14 mM C propionic acid and 1.56 mM C acetic acid. It was observed that the influence of acidic pH on the concentrations of mixed-liquor suspended solids and biomass was stronger than that of basic pH, and the maximal cell growth appeared at pH 7.6. The observed uptake rate of propionic acid was much faster than that of acetic acid at all pH values investigated, and both were affected by pH. The anaerobic transformations of polyhydroxyalkanoates and glycogen linearly decreased with increasing pH from 6.6 to 8.6, and a greater glycogen transformation correlated to greater polyhydroxyalkanoate transformation in both anaerobic and aerobic stages. Further studies revealed that at pH 6.6 and 8.6 the overall phosphorus release and uptake was low and there was no net phosphorus removal, although the initial phosphorus release was high. However, when the pH was controlled at pH 7.1 and 7.6, a phosphorus removal efficiency of 97.03% and 96.43% was achieved, respectively, which was greater than that of 87.46% at uncontrolled pH. Copyright © 2006 Society of Chemical Industry [source]

    Purification of metallurgical-grade silicon up to solar grade

    PROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2001
    N. Yuge
    An estimate has been made of the feasibility of a metallurgical purification process, the NEDO (New Energy and Industrial Technology Development Organization) melt-purification process, for manufacturing solar-grade silicon from metallurgical-grade silicon. Equipment has been developed to pilot manufacturing plant scale. The system comprises an electron-beam furnace for phosphorus removal and a plasma furnace for boron removal. Each furnace has a mold for directional solidification to remove metallic impurities. The concentration of each impurity in the silicon ingot purified through the whole process satisfied the solar-grade level. The Solar-grade silicon produced showed p -type polarity and resistivity within the range 0·5,1·5,,,cm. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Identification and comparison of aerobic and denitrifying polyphosphate-accumulating organisms

    BIOTECHNOLOGY & BIOENGINEERING, Issue 2 2003
    Raymond J. Zeng
    Abstract Two laboratory-scale sequencing batch reactors (SBRs) were operated for enhanced biological phosphorus removal (EBPR) in alternating anaerobic,aerobic or alternating anaerobic,anoxic modes, respectively. Polyphosphate-accumulating organisms (PAOs) were enriched in the anaerobic,aerobic SBR and denitrifying PAOs (DPAOs) were enriched in the anaerobic,aerobic SBR. Fluorescence in situ hybridization (FISH) demonstrated that the well-known PAO, "Candidatus Accumulibacter phosphatis" was abundant in both SBRs, and post-FISH chemical staining with 4,6-diamidino-2-phenylindol (DAPI) confirmed that they accumulated polyphosphate. When the anaerobic,anoxic SBR enriched for DPAOs was converted to anaerobic,aerobic operation, aerobic uptake of phosphorus by the resident microbial community occurred immediately. However, when the anaerobic,aerobic SBR enriched for PAOs was exposed to one cycle with anoxic rather than aerobic conditions, a 5-h lag period elapsed before phosphorus uptake proceeded. This anoxic phosphorus-uptake lag phase was not observed in the subsequent anaerobic,aerobic cycle. These results demonstrate that the PAOs that dominated the anaerobic,aerobic SBR biomass were the same organisms as the DPAOs enriched under anaerobic,anoxic conditions. © 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 83: 140,148, 2003. [source]