The physicochemical characteristics and anaerobic degradability of desiccated coconut industry waste water

Chanakya, HN and Khuntia, Himanshu Kumar and Mukherjee, Niranjan and Aniruddha, R and Mudakavi, JR and Thimmaraju, Preeti (2015) The physicochemical characteristics and anaerobic degradability of desiccated coconut industry waste water. In: ENVIRONMENTAL MONITORING AND ASSESSMENT, 187 (12).

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Abstract

Desiccated coconut industries (DCI) create various intermediates from fresh coconut kernel for cosmetic, pharmaceutical and food industries. The mechanized and non-mechanized DCI process between 10,000 and 100,000 nuts/day to discharge 6-150 m(3) of malodorous waste water leading to a discharge of 2646642 kg chemical oxygen demand (COD) daily. In these units, three main types of waste water streams are coconut kernel water, kernel wash water and virgin oil waste water. The effluent streams contain lipids (1-55 g/l), suspended solids (6-80 g/l) and volatile fatty acids (VFA) at concentrations that are inhibitory to anaerobic bacteria. Coconut water contributes to 20-50 % of the total volume and 50-60 % of the total organic loads and causes higher inhibition of anaerobic bacteria with an initial lag phase of 30 days. The lagooning method of treatment widely adopted failed to appreciably treat the waste water and often led to the accumulation of volatile fatty acids (propionic acid) along with long-chain unsaturated free fatty acids. Biogas generation during biological methane potential (BMP) assay required a 15-day adaptation time, and gas production occurred at low concentrations of coconut water while the other two streams did not appear to be inhibitory. The anaerobic bacteria can mineralize coconut lipids at concentrations of 175 mg/l; however; they are severely inhibited at a lipid level of = 350 mg/g bacterial inoculum. The modified Gompertz model showed a good fit with the BMP data with a simple sigmoid pattern. However, it failed to fit experimental BMP data either possessing a longer lag phase and/or diauxic biogas production suggesting inhibition of anaerobic bacteria.

Item Type:	Journal Article
Publication:	ENVIRONMENTAL MONITORING AND ASSESSMENT
Publisher:	SPRINGER
Additional Information:	Copy right for this article belongs to the SPRINGER, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS
Keywords:	Coconut industry; Waste water; Lipids; Anaerobic digestion; Volatile fatty acids; Biomethane potential; Modified Gompertz model
Department/Centre:	Division of Mechanical Sciences > Centre for Sustainable Technologies (formerly ASTRA) Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	07 Jan 2016 07:11
Last Modified:	07 Jan 2016 07:11
URI:	http://eprints.iisc.ac.in/id/eprint/53043

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