A pilot-scale study on PVA gel beads based integrated fixed film activated sludge (IFAS) plant for municipal wastewater treatment.

In the present study, a pilot-scale reactor incorporating polyvinyl alcohol gel beads as biomass carrier and operating in biological activated sludge mode (a combination of moving bed biofilm reactor (MBBR) and activated sludge) was investigated for the treatment of actual municipal wastewater. The results, during a monitoring period of 4 months, showed effective removal of chemical oxygen demand (COD), biological oxygen demand (BOD) and NH3-N at optimum conditions with 91%, ∼92% and ∼90% removal efficiencies, respectively. Sludge volume index (SVI) values of activated sludge varied in the range of 25-72 mL/g, indicating appreciable settling characteristics. Furthermore, soluble COD and BOD in the effluent of the pilot plant were reduced to levels well below discharge limits of the Punjab Pollution Control Board, India. A culture dependent method was used to enrich and isolate abundant heterotrophic bacteria in activated sludge. In addition to this, 16S rRNA genes analysis was performed to identify diverse dominant bacterial species in suspended and attached biomass. Results revealed that Escherichia coli, Pseudomonas sp. and Nitrosomonas communis played a significant role in biomass carrier, while Acinetobactor sp. were dominant in activated sludge of the pilot plant. Identification of ciliated protozoa populations rendered six species of ciliates in the plant, among which Vorticella was the most dominant.

Taxonomic description and genome sequence of Rheinheimera mesophila sp. nov., isolated from an industrial waste site.

A novel Gram-staining-negative gammaproteobacterium, designated IITR-13T, was isolated from a pesticide-contaminated soil and characterized using a polyphasic approach. On the basis of 16S rRNA gene sequence analysis, the strain showed the closest similarity (98.7 %) to Rheinheimera tangshanensis JA3-B52T followed by Rheinheimera texasensis A62-14BT (97.7 %) and Rheinheimera soli BD-d46T (97.3 %). The 16S rRNA gene sequence similarity of the novel strain to other members of the genus Rheinheimera was < 97.3 %. However, DNA-DNA hybridization between strain IITR-13T and the type strains of R. tangshanensis, R. texasensis and R. soli was 47.5 ± 0.6, 42.4 ± 0.4 and 39.8 ± 0.3 %, respectively; these values are less than 70 %, a threshold value for delineation of a novel species. The strain had C12 : 0 3-OH, C16 : 0, C17 : 1ω8c, summed feature 3 (C16 : 1ω6c/C16 : 1ω7c) and C18 : 1ω6c as the major fatty acids. The major isoprenoid quinones detected for strain IITR-13T were ubiquinone Q-8 and menaquinone MK-7.The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and seven unknown phospholipids. Based on phenotypic and chemotaxonomic characteristics and analysis of the 16S rRNA gene sequence, the novel strain should be assigned to a novel species, for which the name Rheinheimera mesophila sp. nov. is proposed, with the type strain IITR-13T ( = MTCC 12064T = DSM 29723T). Also, we report the draft genome sequence of Rheinheimera mesophila IITR-13T; the draft genome sequence includes 3 749 903 bases and comprises 3449 predicted coding sequences, with a G+C content of 47.8 %. It consists of 102 contigs (>1000 bp).