Salicylic-Acid-Mediated Enhanced Biological Treatment of Wastewater

Activated sludge represents a microbial community which is responsible for reduction in pollution load from wastewaters and whose performance depends upon the composition and the expression of degradative capacity. In the present study, the role of salicylic acid (SA) has been evaluated for acclimatization of activated sludge collected from a combined effluent treatment plant followed by analysis of the physiological performance and microbial community of the sludge. The biodegradative capacity of the acclimatized activated sludge was further evaluated for improvement in efficiency of chemical oxygen demand (COD) removal from wastewater samples collected from industries manufacturing bulk drugs and dyes and dye intermediates (wastewater 1) and from dye industry (wastewater 2). An increase in COD removal efficiency from 50% to 58% and from 78% to 82% was observed for wastewater 1 and wastewater 2, respectively. Microbial community analysis data showed selective enrichment and change in composition due to acclimatization by SA, with 50% of the clones showing sequence homology to unidentified and uncultured bacteria. This was demonstrated by analysis of partial 16S rDNA sequence data generated from dominating clones representing the metagenome which also showed the appearance of a unique population of clones after acclimatization, which was distinct from those obtained before acclimatization and clustered away from the dominating population.     

Induced Electrical Conductivity of Gamma Irradiated S-Hydroxyquinolinc Metal Complexes

The effect of gamma radiation on the electrical conductivity σ of 8-hydroxyquinoline metal complexes was studied. The induced electrical conductivity for the investigated compounds was found to decrease on increasing radiation dose and approaches nearly that of the ligand at doses range from 3 to 5 MGy (300 to 500 Mrd). On the other hand, the increase in the activation energy ΔE by irradiation was found to depend on the crystal field stabilization energy (C.F.S.E.) in high spin tetrahedral field and the ionic potential of the metal.     

Effect of Gamma Radiation on the IR Spectra of Some Divalent and Trivalent 8-Hydroxyquinoline Complexes

The I R spectra of ten elements chelated with 8-hydroxyquinoline were measured before and after gamma irradiation with different doses (7–518 Mrd) and discussed. It was found that the rate of decrease, K, of the absorbancy of M—O and (C—O)-M stretching vibration bands depends on the chelated cation. Moreover, the Cu 8-hydroxyquinoline complex is suggested as gamma dosimeter for doses ranging from 4.8 to 160 Mrd.