Full Length Research Paper

Separation and recovery of organic acids from fermented kitchen waste by an integrated process

Farah Nadia Omar, Nor’Aini Abdul Rahman*, Halimatun Saadiah Hafid, Phang Lai Yee and Mohd Ali Hassan

Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, University Putra Malaysia, 43400 Serdang, Selangor, Malaysia.

*Corresponding author. E-mail: nor_aini@biotech.upm.edu.my.

Tel.: 603 8946 6669.  Fax: 603 8946 7510.

Accepted 4 September, 2009

   Abstract

Organic acids produced from anaerobic digestion of kitchen waste were recovered using a new integrated method which consisted of freezing and thawing, centrifugation, filtration and evaporation. The main organic acid produced was lactic acid (98%). After the freezing and thawing process, 73% of the total suspended solids were removed and the organic acids were elevated from 59.0 to 70 g/L. The evaporation technique was used to further concentrate the organic acids up to 224 g/L. Using the integrated recovery method, the reduction of the total suspended solids in the solution achieved was about 93%. The material balance for the recovery process was also presented.

Key words: Anaerobic digestion, kitchen waste, organic acids, recovery.