ABSTRACT
Plants firing fuel oil produce huge quantities of fly ash as solid waste, which needs to be characterized prior to its proper management. It is worth mentioning that the published literature lack comprehensive information on the characteristics of such fly ash. Characteristics of fuel oil fly ash produced at selected power [PP] and water desalination [DP] plants were determined. The results showed that grain size of the DP fly ash [66.87 microm] is slightly larger than that of PP fly ash [63.09 microm]. The PP fly ash is mostly carbon while DP has a larger percent of metal oxide ashes. Ash content in PP and DP fly ash were 4.8 and 43.3 percent, respectively. Moreover, metal concentrations are higher in DP fly ash than that in PP fly ash. As an example, average vanadium concentrations were 15619 and 40879 mg/kg in PP and DP fly ash samples, respectively. Generally, fly ash samples produced at the two plants are different in their physical and chemical characteristics, which could be attributed to the different fuels and additives being used at the two plants
ABSTRACT
A lab-scale cross flow membrane bioreactor [CF-MBR] was operated to determine the biokinetic coefficients under MLSS concentrations of 5000 and 3000 mg/L. The investigation showed that the yield [Y], the endogenous decay coefficient [k[d], the maximum specific growth rate [micro[m]] and the saturation constant [K[s]] were 0.276 mg/mg, 0.07 /day, 0.653 /day, and 396.62 mg COD/L respectively for MLSS 5000 mg/L, and 0.222 mg/mg, 0.09 /day, 1.2 /day, and 659.45 mg COD/L for MLSS 3000 mg/L. The values of kinetic coefficients were within the normal range of the activated sludge process found in the literature, except the values of Y. However, value of Y increased with the increase of MLSS. Kinetic parameters determined from CF-MBR process were used to simulate the effluent COD. The simulation study showed good agreement between model prediction and experimental data. Sensitivity analysis was carried out to determine influence of biokinetic parameters on the effluent substrate concentration. From the analysis, it was evident that k[d] and K[s] were directly proportional to the effluent substrate concentration, while micro[m] was inversely proportional