Urban runoff treatment using nano-sized iron oxide coated sand with and without magnetic field applying.

Increase of impervious surfaces in urban area followed with increases in runoff volume and peak flow, leads to increase in urban storm water pollution. The polluted runoff has many adverse impacts on human life and environment. For that reason, the aim of this study was to investigate the efficiency of nano iron oxide coated sand with and without magnetic field in treatment of urban runoff. In present work, synthetic urban runoff was treated in continuous separate columns system which was filled with nano iron oxide coated sand with and without magnetic field. Several experimental parameters such as heavy metals, turbidity, pH, nitrate and phosphate were controlled for investigate of system efficiency. The prepared column materials were characterized with Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDXA) instruments. SEM and EDXA analyses proved that the sand has been coated with nano iron oxide (Fe3O4) successfully. The results of SEM and EDXA instruments well demonstrate the formation of nano iron oxide (Fe3O4) on sand particle. Removal efficiency without magnetic field for turbidity; Pb, Zn, Cd and PO4 were observed to be 90.8%, 73.3%, 75.8%, 85.6% and 67.5%, respectively. When magnetic field was applied, the removal efficiency for turbidity, Pb, Zn, Cd and PO4 was increased to 95.7%, 89.5%, 79.9%, 91.5% and 75.6% respectively. In addition, it was observed that coated sand and magnetic field was not able to remove NO3 ions. Statistical analyses of data indicated that there was a significant difference between removals of pollutants in two tested columns. Results of this study well demonstrate the efficiency of nanosized iron oxide-coated sand in treatment of urban runoff quality; upon 75% of pollutants could be removed. In addition, in the case of magnetic field system efficiency can be improved significantly.

Application of Glycyrrhiza glabra root as a novel adsorbent in the removal of toluene vapors: equilibrium, kinetic, and thermodynamic study.

The aim of this paper is to investigate the removal of toluene from gaseous solution through Glycyrrhiza glabra root (GGR) as a waste material. The batch adsorption experiments were conducted at various conditions including contact time, adsorbate concentration, humidity, and temperature. The adsorption capacity was increased by raising the sorbent humidity up to 50 percent. The adsorption of toluene was also increased over contact time by 12 h when the sorbent was saturated. The pseudo-second-order kinetic model and Freundlich model fitted the adsorption data better than other kinetic and isotherm models, respectively. The Dubinin-Radushkevich (D-R) isotherm also showed that the sorption by GGR was physical in nature. The results of the thermodynamic analysis illustrated that the adsorption process is exothermic. GGR as a novel adsorbent has not previously been used for the adsorption of pollutants.

Treatment of saline wastewater by a sequencing batch reactor with emphasis on aerobic granule formation.

The formation and characteristics of aerobic granules in a sequencing batch reactor (SBR), designed to treat saline wastewater, have been investigated in this study. Granule structure was determined using scanning electron microscope (SEM), and polymerase chain reaction (PCR). Granules formed in the reactors were grouped into light brown granules and black granules that looked 'fluffy'. The first group was more dense than the second group and consequently had a higher settling velocity. The densities of the first and the second group were 0.056 and 0.035 g/ml, respectively. While the corresponding settling velocity were 1.35 and 0.97 cm/s, respectively. The kinetic coefficients K(s), k(d), k and Y in saline substrate (10 g NaCl/l) were estimated to be 195 mg s COD/l, 0.025 g VSS/g VSS d, 2.29 g s COD/g VSS d and 0.45 mg VSS/mg s COD, respectively. Analysis of granules using 16S rDNA sequences showed that the dominant microbial species was Klebsiella oxitoca. Minerals and the protozoan community in saline substrate facilitated the formation of granules. It was concluded that the fluffy granules are a variation of the light brown granules which are resistant to salt.