Simultaneous Carbon-Oxidation and Nutrient (N and P) Reduction in a Batch-Fed Reactor by Pseudomonas sp. P1 Isolated from a Small-scale Slaughterhouse Wastewater

Abstract

Aims: Laboratory scale evaluation of phosphorus removal along with organic and nitrogen reduction in a batch reactor under anoxic-aerobic environment using Phosphorous Accumulating Organisms (PAOs). Study Design: Isolation of the predominant bacterial species through phenotypic and phylogenetic characterization of acclimatized sludge collected from a slaughterhouse wastewater treatment plant. Selected isolates able to utilize acetate compounds as superior carbon and energy source in sequential mode of operation. Place and Duration of Study: Environmental engineering Laboratory, Department of Civil Engineering, Jadavpur University, Kolkata, India from March 2013 until October 2015. Methodology: Biological phosphorous study was performed in presence of acclimatized PAOs under anoxic and aerobic condition environment in a batch fed reactor. Selection and Isolation of the most potent isolate and identify PAO species by 16S rDNA study. Thereafter, kinetics study of phosphorous reduction in presence of organic carbon and nitrogen source along with some important process parameters affecting the performance. Results: Molecular phylogenetic identification, supported by chemotaxonomic and physiological properties assigned isolated PAOs (Pseudomonas sp. P1) as a close relative (99%) of Pseudomonas aeruginosa. Isolated PAOs (Pseudomonas sp. P1) showed that 94.30% SCOD reduction from an initial SCOD value of 600±20 mg/L and 81.38% and 87.98% of NH4+-N and PO43--P removal from an initial NH4+-N and PO43--P concentration of 50±5 and 10±1 mg/L, after 24 hr contact period in a batch reactor.  Conclusion: The investigation result demonstrated that the bacterial species Pseudomonas sp.P1 exhibited appreciable removal of phosphorous along with organic (SCOD), nitrogen (NH4+-N, NO3--N) in the batch reactor under anoxic and aerobic condition sequentially which may be applied for real life situation particularly to treat slaughterhouse effluent.