Pretreatment of wastewater containing a mixture of organic pollutants obtained from a CC2 plant by coagulation.

Coagulation is one of the most important physicochemical treatment steps in industrial wastewater to reduce the suspended and colloidal materials responsible for colour and turbidity of the wastewater. The manufacturing plant of N,N'-Dichloro bis (2,4,6-trichlorophenyl) urea (CC2) produces wastewater containing pyridine, acetic acid and diphenyl urea (DPU). The wastewater also contains lot of suspended solids like CC2 and various poly-aromatic compounds. In our present investigation, our basic aim was to find an effective coagulation process for the pretreatment of wastewater discharged from the CC2 plant. Studies were conducted to find out a suitable and effective coagulant for pretreatment of this wastewater. Various coagulating agents such as alum, ferric chloride, sodium carboxymethyl cellulose (Na-CMC) were used. Alum was found to be the most effective coagulant. Coagulation of the wastewater resulted in the total suspended solids (TSS) removal in the range of 92-94% and chemical oxygen demand (COD) removal in the range of 59 to 65% at a dose of 500 mg L(-1) of alum at a pH>or=7.0. After coagulation the concentration of pyridine in wastewater was found to be reduced by 10.0% and that of DPU 40-45% with a dosage of 500 mg L(-1) alum.

Japanese Encephalitis Outbreak, India, 2005.

An outbreak of viral encephalitis occurred in Gorakhpur, India, from July through November 2005. The etiologic agent was confirmed to be Japanese encephalitis virus by analyzing 326 acute-phase clinical specimens for virus-specific antibodies and viral RNA and by virus isolation. Phylogenetic analysis showed that these isolates belonged to genogroup 3.

Adsorption of dimethyl methylphosphonate on metal impregnated carbons under static conditions.

Active carbon, grade 80 CTC, of surface area 1199m(2)/g, 12x30 BSS particle size and coconut shell origin was impregnated (5%, W/W) with various impregnants such as Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate, Cu(II) 1,1,1-trifluoroacetylacetonate, 1-phenylbute-1,3-dione-2-oxime plus Cu(II) using incipient wetness technique. These impregnated carbons along with active carbon (Grade 80 CTC) and whetlerite were studied for the adsorption of dimethyl methylphosphonate (DMMP) at 33+/-1 degrees C under static conditions. Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate impregnated carbon system showed highest uptake (68.5%, W/W) of DMMP amongst all the carbon systems, however, active carbon with higher surface area could adsorb 61.5% (W/W) of DMMP under same conditions. It indicated that the adsorption by Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate impregnated carbon was not only due to physisorption but chemisorption as well. Kinetics of adsorption was also studied and various parameters such as equilibration time, equilibration capacity, rate constant (k), diffusional exponent (n) and constant (K) were determined. Carbons with and without DMMP exposure were also studied using IR and TGA techniques. Reaction products were analyzed using gas chromatography coupled with mass spectrometry (GC/MS) and found to be methyl methylphosphonic acid (MMPA) and methylphosphonic acid (MPA) for Cu(II) 1,1,1,5,5,5-hexafluoroacetylacetonate impregnated carbon.

In-situ degradation of sulphur mustard and its simulants on the surface of impregnated carbon systems.

Bis-2-chloroethyl sulphide (sulphur mustard or HD) is an extremely toxic and persistent chemical warfare agent. For in situ degradation of HD and its analogues (simulants), i.e., dibutyl sulphide (DBS) and ethyl 2-hydroxyethyl sulphide (HEES), different carbon systems such as 11-molybdo-1-vanadophosphoric acid impregnated carbon (V(1)/C), ruthenium chloride impregnated carbon (Ru/C) and combination of these two (V(1)/Ru/C) were prepared. These carbons were characterized for cumulative micropore volume and surface area by N(2) BET. The kinetics of the in situ degradation of HD and its simulants were studied and found to be following the first order kinetics. Kinetic rate constants and t(1/2) values were determined. Products were characterized using NMR, IR and GC-MS. Reaction products were found to be sulphoxide and sulphone. The combined system, i.e., 11-molybdo-1-vanadophosphoric acid plus ruthenium chloride (V(1)/Ru/C) was found to be best for in-situ degradation of HD and its simulants. In-situ degradation by polyoxometalate based system was found to be stoichiometry based while Ru/C oxidized HD in presence of chemisorbed oxygen. In combined system of V(1)/Ru/C ruthenium worked as a catalyst and polyoxometalate acted as a source of oxygen. Effect of moisture was also studied in combined system. Rate of degradation of HD was found to be increasing with increased percentage of moisture content.