Recycling Solid Waste from the Olive Oil Extraction Process RIRDC Pub. No. 08/165 RIRDCNew ideas for rural Australia 08-165 solid waste.indd 1 15/10/2008 2:17:55 PM Recycling Solid Waste from the Olive Oil Extraction Process by Assoc. Professor N.G. (Tan) Nair and Dr Julie Markham October 2008 RIRDC Publication No 08/165 RIRDC Project No UWS 20-A © 2008 Rural Industries Research and Development Corporation. All rights reserved. ISBN 1 74151 754 0 ISSN 1440-6845 Recycling Solid Waste from the Olive Oil Extraction Process Publication No. 08/165 Project No. UWS 20-A The information contained in this publication is intended for general use to assist public knowledge and discussion and to help improve the development of sustainable regions. You must not rely on any information contained in this publication without taking specialist advice relevant to your particular circumstances. While reasonable care has been taken in preparing this publication to ensure that information is true and correct, the Commonwealth of Australia gives no assurance as to the accuracy of any information in this publication. The Commonwealth of Australia, the Rural Industries Research and Development Corporation (RIRDC), the authors or contributors expressly disclaim, to the maximum extent permitted by law, all responsibility and liability to any person, arising directly or indirectly from any act or omission, or for any consequences of any such act or omission, made in reliance on the contents of this publication, whether or not caused by any negligence on the part of the Commonwealth of Australia, RIRDC, the authors or contributors. The Commonwealth of Australia does not necessarily endorse the views in this publication. This publication is copyright. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. However, wide dissemination is encouraged. Requests and inquiries concerning reproduction and rights should be addressed to the RIRDC Publications Manager on phone 02 6271 4165. Researcher Contact Details Assoc. Professor N.G.(Tan) Nair Dr Julie Markham Centre for Plant and Food Science School of Natural Science University of Western Sydney University of Western Sydney Phone: + 61(02) 45701332 (Mobile:04 0986 6809) Phone: + 61 (02) 4570 1221 Fax: + 61(02) 45701314 Fax: + (02) 4570 1267 Email: [email protected] Email: [email protected] In submitting this report, the researcher has agreed to RIRDC publishing this material in its edited form. RIRDC Contact Details Rural Industries Research and Development Corporation Level 2, 15 National Circuit BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: 02 6271 4100 Fax: 02 6271 4199 Email: [email protected]. Web: http://www.rirdc.gov.au Published in October 2008 by Union Offset ii Foreword The main objective of the project was to recycle solid waste produced from the 2- and 3-phase olive oil mill extraction processes. A composting technique was developed for this purpose that can be applied as an olive mill waste management tool. The technique is characterised by process efficiency and low cost. The process was used for composting olive husk waste collected from 2005, 2006 and 2007 harvests. The study was done over three years at three sites in New South Wales. The olive industry will benefit from the results of this project by being able to convert liabilities (wastes) to assets (value-added compost). The consequence is management of environmental pollution, and sustainable and responsible farming practices. The amendment of olive grove soil with the olive husk compost will assist in healthy growth of the trees by improving the physical, nutritional and microbial status of the soil. The key findings of the project are the ability to covert the raw, phytotoxic olive husk waste to non- phytotoxic compost high in organic matter. There was a gradual decrease in the level of phenols in the olive husk during the composting process resulting in a product which is amenable to the growth of plants. A new procedure for extracting phenol was developed successfully in this project for the purpose of assaying phenols in the compost. Using this method, levels of phenol in the compost dropped from 29.68 mg/g at the early stages of the process to 8.9 mg/g at the completion. Although the majority of Australian olive growers use the 2-phase oil extraction process, the composting procedure developed in this project was found to be applicable to both the 2- and 3-phase olive husk wastes. This project was funded from RIRDC Core Funds which are provided by the Australian Government and, from cash and in-kind contributions from Rylstone Olive Press, Rylstone, NSW,and in-kind contributions from Lakelands Olives, Clandulla, NSW, Southern Cross Laboratories, Dural, NSW, and Glenlee Olive Grove, Camden, NSW. This report is an addition to RIRDC’s diverse range of over 1800 research publications and forms part of our New Plant Products Program that facilitates the aims of new industries based on plants or plant products having commercial potential in Australia Most of our publications are available for viewing, downloading or purchasing online through our website: • downloads at www.rirdc.gov.au/fullreports/index.html • purchases at www.rirdc.gov.au/eshop Peter O’Brien Managing Director iii Acknowledgments Financial contributors: Rural Industries Research and Development Corporation, Jayne Bentivoglio, Rylstone Olive Press, Rylstone, NSW. In-kind contributors: Jayne Bentivoglio, Rylstone Olive Press, Rylstone, NSW; Knut Kammann, Lakelands Olives, Clandulla, NSW; Robert Unsworth, Southern Cross Laboratories, Dural, NSW; Trish and David Wilson, Glenlee Olive Grove, Camden, NSW. Adrian Moller, Rylstone Olive Press; Shane Pennell, Lakelands Olives; Karl Kelleman, Glenlee Olive Grove for their valuable assistance with preparation olive husk compost. Roslyn Woodfield, Centre for Plant and Food Science, University of Western Sydney, for technical assistance with laboratory assays. Liz Kabanoff, Centre for Plant and Food Science, University of Western Sydney, for assistance in the preparation of scanning electron micrographs. iv Contents Foreword ............................................................................................................................iii Acknowledgments ...............................................................................................................iv List of Tables ......................................................................................................................vi List of Figures .....................................................................................................................vi Executive Summary ...........................................................................................................vii Introduction.........................................................................................................................1 Objectives ............................................................................................................................6 Methodology ........................................................................................................................7 Results ...............................................................................................................................10 Discussion ..........................................................................................................................23 The problem - The olive mill waste...........................................................................................23 The solution to the problem .......................................................................................................23 The olive oil extraction methods versus the olive mill waste ....................................................24 Physical characteristics of olive husk ........................................................................................24 Olive husk composting process..................................................................................................24 Conclusions................................................................................................................................27 Implications .......................................................................................................................28 Recommendations..............................................................................................................29 Composting recommendation ....................................................................................................29 Steps to disseminate the results of the project ...........................................................................29 Further development to maximise the results of the project ......................................................29 References..........................................................................................................................30 Appendices.........................................................................................................................35 v List of Tables Table 1 – Comparison of solid and liquid wastes* produced by the 2- and 3-phase olive oil extraction processes.......................................................................................................... 2 Table 2 – Comparisons of some characteristics of olive waste (olive husk) generated ................... 2 Table 3 – Composition of the trial batches used in composting