International Journal of Environmental Sciences

Volume 3 Issue 1 2012- July 2012        Pages: 181- 191            <<Previous    Next>>

Performance of mixture of vegetable wastes with high carbohydrate content in anaerobic digestion process

Author Information:

Dhanalakshmi Sridevi.V1, Alwar Ramanujam.R2
1. Department of Chemistry, G K M College of Engineering & Technology, Chennai,
INDIA - 600063
2. Environment Technology Division, Central Leather Research Institute (CLRI),
Council of Scientific and Industrial Research (CSIR), Adyar, Chennai, INDIA - 600020

ABSTRACT

In our present study anaerobic digestion of mixture of vegetable wastes has been conducted in batch reactors of 500 ml capacity.   Vegetable wastes having near similar pH and moisture content have been chosen so that total solids content do not vary significantly in the feed composition for the study.  Carrot, beans and brinjal having pH 5.4, 5.8 and 5.7 respectively and moisture content 89.8%, 90.29% and 89.4% respectively were chosen for the study.  These wastes contain predominantly carbohydrates and less protein and fat.  Studies were carried out by preparing the feed consisting of carrot, beans and brinjal in different proportions to obtain organic load in three different ranges namely 0.06-0.09 gm VS, 0.13-0.17 gm VS and 0.19-0.26 gm VS.  The reactors were operated at these three different organic loads at various retention times.  The performance of the reactors was evaluated by estimating destruction of Total and Volatile Solids and by monitoring daily gas production.  Volatile Fatty Acid (VFA) profile was determined for each organic load at the end of each cycle of operation.  VFAs particularly acetic acid, propionic acid and valeric acid were present predominantly in all the three organic load ranges. The performance evaluation in terms of specific gas production based on amount of total solids added and volatile solids added has indicated that the mixture of vegetable wastes chosen for the study are amenable to anaerobic digestion.  The kinetics of the process has been studied using first order rate equation and reported in the paper.

Keywords: Anaerobic digestion, fruit and vegetable wastes, biogas, batch reactor, VFA profile.

DOI: 10.6088/ijes.2012030131018

© 2012 Copyright by the authors, licensee Integrated Publishing Association.This is an open access article distributed under the Creative Commons Attribution License (3.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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