Browsing by Author "Kalibbala, Martin"

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    Fecal Coliform Mortality in Water Hyacinths Ponds
    (2000) Mayo, Aloyce W.; Kalibbala, Martin
    The effects of various environmental factors, sedimentation and attachment of faecal coliforms on water hyacinths, Eichhornia crassipes, were investigated in a pilot-scale water hyacinths pond. This investigation was conducted to evaluate the role of solar intensity, pH, dissolved oxygen, temperature, sedimentation, and attachment of faecal bacteria on Eichhornia crassipes on disappearance of bacteria in a water hyacinths pond. A mathematical model that used the plug flow philosophy and incorporated aforementioned factors to predict faecal coliform mortality rate was developed. The proposed multifactor model satisfactorily predicted mortality rate of faecal coliforms in a pilot-scale water hyacinths constructed wetland. The environmental factors such as solar intensity and pH were the key factors if the coverage of water hyacinths is minimum, but attachment of bacteria to water hyacinths played a major role in a wetland fully covered with water hyacinths.
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    Modelling Faecal Coliform Mortality in Water Hyacinths Ponds
    (2007) Kalibbala, Martin; Mayo, Aloyce W.
    The effects of various environmental factors, sedimentation and attachment of faecal coliforms on water hyacinths, Eichhornia crassipes, were investigated in a pilot-scale water hyacinths pond. This investigation was conducted to evaluate the role of solar intensity, pH, dissolved oxygen, temperature, sedimentation, and attachment of faecal bacteria on Eichhornia crassipes on disappearance of bacteria in a water hyacinths pond. A mathematical model that used the plug flow philosophy and incorporated aforementioned factors to predict faecal coliform mortality rate was developed. The proposed multifactor model satisfactorily predicted mortality rate of faecal coliforms in a pilot-scale water hyacinths constructed wetland. The environmental factors such as solar intensity and pH were the key factors if the coverage of water hyacinths is minimum, but attachment of bacteria to water hyacinths played a major role in a wetland fully covered with water hyacinths.
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    Modelling Faecal Streptococci Mortality in Constructed Wetlands Implanted with Eichhornia Crassipes
    (2008) Kalibbala, Martin; Mayo, Aloyce W.; Asaeda, Takashi; Shilla, Daniel
    Faecal streptococci mortality was investigated in a water hyacinth (Eichhornia crassipes) constructed wetland pond. The wetland was 7.5 m long, 1.5 m wide and 1.0 m deep, and was implanted with E. crassipes. In order to assess the performance of the system towards bacterial mortality, a mathematical model, based on plug flow philosophy was developed. The model incorporated the role of factors, namely solar intensity, pH, dissolved oxygen, temperature, sedimentation, and root attached growth. Model analysis strongly suggests that bacterial mortality rate constant was largely influenced by two factors, namely solar intensity and root biofilm attachment, with both contributing approximately 70.5% of removal. The contribution of other factors like temperature, dissolved oxygen, pH and sedimentation on bacterial mortality rate were less significant. For example, dissolved oxygen, pH and sedimentation contributed 5%, 8% and 0.82%, respectively. Thus, the sedimentation factor was omitted from the model because of its insignificant contribution. The same was done for temperature, due to low ambient temperature range (3.1°C) in the study area. The overall model bacterial removal efficiency was 83%.
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    Phosphorus speciation in Myall Lake sediment, NSW, Australia
    (2009-03) Shilla, Daniel; Asaeda, Takashi; Kalibbala, Martin
    The amount of phosphorus and its fractions in the sediment of Lake Myall, NSW, Australia, was assessed using a sequential extraction technique. Five sedimentary phosphorus reservoirs were measured, namely loosely sorbed phosphorus (NH4Cl–P), iron associated phosphorus (BD–P), calcium bound phosphorus (HCl–P), metal oxide bound phosphorus (NaOH–P) and residual phosphorus (organic and refractory P, Res-P). Samples were taken from the deep and shallow sites of the lake. During the analysis, the average concentrations of each fraction of phosphorus was calculated. The results depicted that the total phosphorus (TP) content and chemically extractable phosphorus in both fine and coarse sediment fractions from the deep sites of the lake were significantly higher than those of the shallow sites, except for HCl–P extracted from the fine sediment fraction. Sediment TP was also strongly and positively correlated to sediment Fe. The phosphorus in the sediment mainly consisted of BD–P and Res-P, while NH4Cl–P and HCl–P only contributed a minor part. The rank order of the different phosphorus extracts was similar for the two sites, namely Residual-P>BD–P>NaOH–P>HCl–P>NH4Cl–P.