In this study, the removal of phenol and naphthalene from aqueous solutions was investigated using different bacterial strains, granular activated carbon and biological activated carbon as a combination of the two systems. Laboratory experiments for adsorption, biodegradation and biosorption of both chemicals were carried out in batch reactors at 25 °C and shaking at 120 revolutions per minute. The experiments in this study showed that the biodegradation process that actually exists did not play a significant role in the removal of both compounds by the suspension containing biomass and GAC.
Furthermore, decreasing the microbial concentration in the BAC system increased the GAC adsorption capacity. Walid Harnza, Head of the Department of Biology who allowed me to work and complete experiments in the Microbiology and Molecular Biology Laboratories. Salem Hegazy from the Department of Civil Engineering, who provided me with the necessary information on the use of laboratory instruments and apparatus.
Khaled El Tarabily, who not only provided me with the information needed to enrich and isolate the bacteria, but also performed the identification step of the isolated microorganisms. My parents and my son Hussam, who played an important role in the development of the thesis, which was the crowning achievement of my academic life.
LIST OF TABLES
R2 coefficient and rate parameters of zero order linearized kinetic equation of phenol and naphthalene bioadsorbed by inactive P7 and Nl7. R2 coefficient and rate parameters of 1 sl order linearized kinetic equation of phenol and naphthalene bioadsorbed by inactive P7 and N 1 7. R2 coefficient and rate parameters of 2nd order linearized kinetic equation of phenol and naphthalene bioadsorbed by inactive P7 and N 1 7.
R2 coefficient and rate parameters of the 3rd order linearized kinetic equation of phenol and naphthalene bioadsorbed by inactive P7 and N 1 7.
LIST OF SYMBO LS
CHAPTER 1
I NTRO DUCTION
CHAPTER 2
LITERATURE REVIEW
CHAPTER 3
CHAPTER 4
1 and 4.2 clearly showed that there is no loss of phenol and naphthalene in the control sample (empty solution without activated carbon) due to evaporation and or decomposition on the walls of the container under the conditions of the experiments. The high affinity between naphthalene and GAC is probably the result of the molecules favorably accumulating more tightly than that of phenol. Finally the stationary phase continued until the end of the experiment (1 5 days) without breaking.
The results showed that the uptake of phenol reached equilibrium within the first 100 hours of the experiment. The reduction of phenol and naphthalene during the process may be due to the biological action of the bacteria (degradati n) and biosorption of its wall cells alone. When N16 was used inside the bacterial system and the BAC system to remove 30 ppm naphthalene, no significant difference in growth rate was observed.
The results showed that phenol removal using BAC as well as using bacteria reached equilibrium within the first 100 hours of the test. On the other hand, the blockage of GAC micropores by bacterial cells had decreased its adsorption efficiency. Overall pollutant removal was limited to adsorption using the remaining unblocked micropores of the GAC and degradation by growing bacteria.
1 3 Phenol removal with the same concentrations of biomass P l O within the bacterial system and the BAC system ( 100 vol. Inactive bacteria were considered as carbon adsorption material, whose cell walls contained the active sites necessary for the adsorption of both chemicals. using a 40% concentration bacteria increased phenol biosorption by 6% using inactive P7 cells.
19 and Figure 4.20 showed that the use of inactive bacteria did not increase the GAC removal capacity. It is expected that the removal of phenol or naphthalene using biomass alone was achieved by the degradation and adsorption of these chemicals at the active sites of the cell walls within the bacterial system. The only increase in the biosorption capacity of phenol and naphthalene was achieved when the concentration of bacteria (volumetric reduction of the suspended biomass solution) was combined with GAC in the biosorption system.
MA THEM A TICAL M ODELING
The general equation of the rate of phenol removed from inactive BAC can be described in Equations (39) and (40). According to these values, about 80% of the total biological activity for phenol removal was due to surface absorption on the cell walls, while less than 2 1% of this activity was due to biodegradation. In the case of naphthalene, the contribution of surface biosorption was higher than that of phenol.
This conclusion is consistent with the decrease in concentrations observed when using active BAC and inactive BAC. The ratio of surface absorption to biological activity (aphenol = 0.797, anaphthalene = 0.844) was used to observe the increase in the number of active sites in GAC when decreasing the concentration of bacteria used within the inactive BAC. Where /phenol 40% and /naphthalene 45% are the fraction of active sites available in GAC when 40% and 45% of bacterial suspension are used to remove phenol and naphthalene, respectively.
Using 40% by volume of bacterial suspension combined with GAC within the BAC system for phenol removal would leave an additional 12% of the GAC active site free of bacteria (unblocked). In addition, the use of 45% suspension instead of 100% within the BAC increased the proportion of GAC active site that adsorbed naphthalene by 25%. About 30% of the active sites were free of bacteria and able to adsorb naphthalene in the presence of bacteria.
In general, the use of less concentration of bacteria in the BAC system improved the adsorption capacity of GAC.
CHAPTER 6
Lower removal (compared to removal by activated carbon) of phenol and naphthalene was obtained when biomass alone was present. Removal of the two compounds was improved using a combined system of biomass and activated carbon, but did not reach the removal achieved by activated carbon alone. This indicated that the use of biomass in suspension blocks some of the available area for sorption on the activated carbon.
The removal of phenol and naphthalene with a slurry containing inactive biomass plus GAC closely matched that with active biomass. This indicated that biodegradation, which does exist, did not play a major role in the removal of the two compounds. The contribution of biodegradation process in the overall removal of phenol and naphthalene in BAC system was equal to 0.2 and 0.
The fraction of available active sites on GAC (f) when using 1 00 % (vol.) of bacterial suspension in BAC system was equal to 0.2585 and 0.049 for phenol and naphthalene, respectively. Based on calculations, only one fourth of the active sites on the surface of GAC were used to adsorb phenol within the active BAC system, while 5% of the active sites were adsorbed naphthalene. The biological activity in an activated carbon system for pollutant removal can be improved by using immobilized cells attached to solid material instead of.
Therefore, the detrimental effect of the free cells in blocking the active sites on GAC will no longer occur during biosorption. In addition, the use of nitrogen or phosphorus compounds as bacterial nutrients can improve the removal efficiency through degradation. It is very important to study the performance of a BAC system under varying concentrations of biomass to achieve the highest possible numbers of free active sites on GAC.
The determination of the amount of chemicals biologically adsorbed using only inactive bacteria can be applied in the future to investigate the removal efficiency of this system. Further investigation can be applied to measure the adsorbed amount of chemicals on the cell walls of bacteria by means of a chemical extraction in order to confirm the contribution of the three expected removal mechanisms in BAC system. In conclusion, it is very important to study the removal efficiency of bacteria isolated from the local environment of the UAE using different reactor designs to investigate their degradation ability in the field industry.
RE FEREN CES
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Fox, P., en Suidan, M.T Shock and Transient Loading On Anaerobic Reactor Coupled with Absorber", Journal of Environmental Engineering, Vol. R Granular Activated Carbon and Biological Activated Carbon Treatment of Dissolved and Sorbed Polychlorinated Biphenyls", Water Environmental Research, Vol. . 34;Biodegradasie van antraseen en fluoranteen deur fungi geïsoleer uit 'n eksperimentele gekonstrueerde vleiland vir afvalwaterbehandeling", Water Research, Vol.
Temperature Effects of Trickle-Bed Biofilter For Treating BTEX Vapors", Journal of Environmental Engineering Vol. Nutt S.G., 1 989, 'Optimization and Control Petroleum Refinery Wastewater Treatment Systems-Status, Trends and Needs", Water Pollution Research Journal o/Canada, Full. Shim, 1.S., Lewandowski, G.A. Comparison of various measures of microbial growth kinetics in suspended and biofilm cultures during biodegradation of naphthalene", Water Environment Research, Vol.
M Biodegradation of Petroleum Wastewater in a Modified Rotating B iological Contactor, with Polyurethane Foam Attached to Discs", Water Resources, Vol. Vol. Yu-Chun Chiang P.E., Pen-Chi Chiang, P.E., and Chang, E.E Effects of Surface Characteristics of Activated Carbons on VOC Adsorption", Journal of Environmental Engineering, Vol.
