To understand the effect of HRT and SRT on parameters was the prime motive of the studies. The parameters such as chemical oxygen demand (COD), soluble COD (Sol.COD), biochemical oxygen demand (BOD), nitrogen (ammonia NH4, nitrate NO3) contents and phosphorus contents (Phosphate PO4), total suspended solids (TSS) and volatile suspended solids (VSS), soluble microbial products (SMP), proteins, carbohydrates, acetate and alkalinity (ALK) for hospital wastewater and residential quarter wastewater were considered . The experiments have been performed on laboratory-scale hollow fiber submerged membrane bioreactor (MBR) for wet season i.e. rainy season. The results have discovered a high removal efficiency of COD, BOD and ammonia which ranged between 93.15 to 97.98 %, 94.20 to 98.74 % and 97.21 to 98.74 %, respectively. While, for TSS and VSS, the removals were found to above 99.00 %. The phosphorus removal efficiency (54.55 to 58.00 %) was found to be inadequate compare to other parameters. The removal efficiencies decreased with increase in HRT, while efficiency increased with increase in SRT. Better results were obtained with residential wastewater as compared to hospital wastewater. Keywords: sludge retention time, hydraulic retention time, removal efficiency, wet season

In Y2 O3–Al2 O3 system, compounds Y3 Al5 O12 (yttrium aluminum garnet-YAG), YAP (yttrium aluminum perovskite-YAlO3,) and Y4 Al2 O9 (yttrium aluminate monoclinicYAM,) are well known. YAG and YAP are of considerable technological importance. The conventional solid-state reaction techniques require high sintering temperatures (above 1800°C) to prepare phase pure compounds. Though several soft chemical routes have been explored for synthesis of YAG, YAP and YAM, most of these methods are complex. Moreover, phase pure materials are not obtained in one step, but prolonged annealing at temperatures around 1000 C is necessary. One step combustion synthesis of these compounds is reported in this paper using a modified procedure and employing mixed (glycine + urea) fuel. Phosphors based on Eu3+ activation were also prepared which exhibited characteristic photoluminescence. The emission spectrum of Eu3+ doped YAG phosphor is dominated by orange emission due to 5 D0- 7 F1 transition with inversion symmetry. However, the emission spectrum of Eu3+ doped YAP phosphor is dominated by red emission due to 5 D0- 7 F2 transition without inversion symmetry. The PL spectrum of Eu3+ doped YAM phosphor consists of similar emission intensities for both 5 D0- 7 F1 (590 nm) and 5 D0- 7 F2 (607 nm) transitions. Keywords: phosphors; combustion synthesis; luminescence; Eu3+; YAG ; YAP ; YAM

Recently in this laboratory a new route for the synthesis of 2-chloro-4, 6- distitutedthiocarbamido-1, 3, 5-triazines was developed to increase the yield of products by maintaining the purity of them and the time span required for the completion of reactions was also decreases. These are eco-friendly reactions. Novel green synthesis ofchloro-4,6-distitutedthiocarbamido-1,3,5-triazines (IIIa-e) was successfully carried out by interacting cyanuryl chloride (I) with various thiourea in (IIa-e) in 1:2 molar ratio in ethanol-acetone medium. During the synthesis parameters of green chemistry are maintained. The justification and identification of the structure of these newly synthesized compounds had been established on the basis of chemical characteristics, elemental analysis and through spectral data. Keywords: Green synthesis, cyanuryl chloride, substitutedthiourea, 1, 3, 5-triazine, acetone-ethanol.