In this study, the performance of powdered activated carbon(PAC) contactor located in the Hakya water treatment plant(WTP) was evaluated. The result of tracer tests showed that the plug flow portion was more than 70 %. According to the total organic carbon(TOC) data of target WTP, there were no clear evidence that the addition of PAC contributed to the removal of organics. However, the results of jar test, conducted with the raw water taken from the Hakya WTP, proved that PAC could remove dissolved organic carbon(DOC) to some extent when the proper velocity gradient was maintained. It was estimated that the production rate of Hakya WTP, defined as the ratio of the operating flow rate to the design flow rate, was only 50 %. Because of this lower production rate, the mixing intensity in the contactor is much less than the designed value and, finally, the performance of PAC contactor was much less than what was expected.

Recent studies have revealed the poisonous nature of aluminum(III) species to aquatic and terrestrial organisms. Therefore, this investigation aims to develop batch adsorption experiments in the laboratory, aiming to the removal of aluminum(III) from aqueous solutions onto powdered activated carbon (PAC). The latter (which is an effective and inexpensive sorbent) was prepared from olive stones generated as plant wastes and modified with an aqueous modifying oxidizing agent, viz. HNO3. The main parameters (i.e. initial solution pH, sorbent and Al3+ ions concentrations, stirring times and temperature) influencing the sorption process were examined. The results obtained revealed that the sorption of Al3+ ions onto PAC is endothermic in nature and follows first-order kinetics. The adsorption data were well described by the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) adsorption models over the concentration range studied. Under the optimum experimental conditions employed, the removal of ca. 100% Al3+ ions in the concentration range 1.35-2.75 mg·l-1 was attained. Moreover, the procedure was successfully applied to the recovery of aluminum spiked to some environmental water samples with an RSD (%), does not exceed 1.22%.