Removal of carbamazepine from aqueous solution by adsorption on fly ash-amended soil

Carbamazepine (CBZ), nonbiodegradable pharmaceutical residue, has become an emerging pollutant in several aquatic environments. The effectiveness of the mixture of soil and fly ash (FA) in adsorbing CBZ from aqueous solution has been studied as well as agitation time, FA content, initial CBZ concentration and desorption as a function of FA content. The adsorption kinetics fits a hyperbolic or pseudo-second-order model. The maximum adsorbed amounts for natural soil and a mixture of soil/FA ranged from 77 to 158 mg kg−1. Rate constants were considered relatively low (4.15–15.59 × 10−4 kg mg−1 min). The logarithmic form of the Freundlich equation gave a linearity and the Kf constants increased with the increase of FA content in adsorbent mixtures and with the affinity between the adsorbent surface and adsorbed solute. The mean removed amounts of CBZ by adsorption batch experiments in a soil mixture with 30% FA content were up to 92.8% for coal FA and 33% in natural soil. This work proved that the mixture of the coal FA and soil can be used as an efficient adsorbent material for removal of CBZ from water.

Removal of pharmaceutical residue in municipal wastewater by DAF (dissolved air flotation)–MBR (membrane bioreactor) and ozone oxidation

Growing attention is given to pharmaceutical residue in the water environment. It is known that pharmaceuticals are able to survive from a series of wastewater treatment processes. Concerns regarding pharmaceutical residues are attributed to the fact that they are being detected in water and sediment environment ubiquitously. Pharmaceutical treatment using a series of wastewater treatment processes of the DAF (dissolved air flotation)–MBR (membrane bioreactor)–ozone oxidation was conducted in the study. DAF, without addition of coagulant, could remove CODcr (chemical oxygen demand by Cr) up to over 70%, BOD 73%, SS 83%, T-N 55%, NH4+ 23%, and T-P 65% in influent of municipal wastewater. Average removal rates of water quality parameters by the DAF–MBR system were very high, e.g. CODcr 95.88%, BOD5 99.66%, CODmn (chemical oxygen demand by Mn) 93.63%, T-N 69.75%, NH4-N 98.46%, T-P 78.23%, and SS 99.51%, which satisfy effluent water quality standards. Despite the high removal rate of the wastewater treatment system, pharmaceuticals were eliminated to be about 50–99% by the MBR system, depending on specific pharmaceuticals. Ibuprofen was well removed by MBR system up to over 95%, while removal rate of bezafibrate ranged between 50 and 90%. With over 5 mg/l of ozone oxidation, most pharmaceuticals which survived the DAF–MBR process were removed completely or resulted in very low survival rate within the range of few micrograms per litre. However, some pharmaceuticals such as bezafibrate and naproxen tended to be resistant to ozone oxidation.