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Pilāni, India

Kalyanaraman C.,CSIR - Central Leather Research Institute | Sri Bala Kameswari K.,CSIR - Central Leather Research Institute | Sudharsan Varma V.,CSIR - Central Leather Research Institute | Tagra S.,BITS Pilani Pilani Campus | Raghava Rao J.,CSIR - Central Leather Research Institute
Clean Technologies and Environmental Policy | Year: 2013

Fat liquoring, a post-tanning operation is carried out on tanned leather using oils, fats, or greases in emulsion form to make soft leathers and to improve the physical characteristics of the finished products during leather manufacturing. Around 10-15 % of un-exhausted fat liquor is discharged in the process water as wastewater. The major components of vegetable fat liquor are triacylglycerols, which primarily consist of glycerol molecules esterified with long chain fatty acids. The presence of fats, grease, and oils not only causes choking of wastewater conveyance mains but also interferes with the oxygen-transfer efficiency in aerobic treatment process. The aim of the present study is to assess the rate of biodegradability of vegetable-based fat liquor-containing wastewater generated from tanneries for various food to microbial (f/m) ratio, i.e., 0.35, 0.25, and 0.15 g biochemical oxygen demand (BOD5)/g volatile suspended solids (VSSs) day. The f/m ratio and reaction time were investigated in detail in aerobic batch reactor to arrive at the optimum ratio needed for biodegradation of vegetable fat liquor. From the aerobic biodegradation studies, it was established that at an f/m ratio of 0.15 and a reaction time of 24 h, BOD5 and chemical oxygen demand removals were 97.24 and 89.58 %, respectively. It was evident from Fourier transform infrared spectrometry and electrospray ionization-mass spectroscopy analysis that the triglycerides present in vegetable fat liquor were degraded effectively. © 2012 Springer-Verlag Berlin Heidelberg. Source

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