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Combination of Fenton oxidation and composting for the treatment of the olive solid residue and the olive mile wastewater from the olive oil industry in Cyprus
Antonis A. Zorpas a,*, Costa N. Costa b
aInstitute of Environmental Technology and Sustainable Development, Department of Research and Development, Laboratory of Environmental Friendly Technology, P.O. Box 34073, 5309, Paralimni, Cyprus b Cyprus University of Technology, Department of Environmental Management, Cyprus
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Co-composting of olive oil solid residue (OOSR) and treated wastewaters(with Fenton) from the olive oil production process has been studied as an alternative method for the treatment of wastewater containing high organic and toxic pollutants in small olive oil industry in Cyprus. The experimental results indicated that the olive mill wastewater (OMW) is detoxiﬁed at the end of Fenton Process and the COD is reduced up to 70%. The ﬁnal co-composted material of OOSR withthe treated olive mile wastewater (TOMW) is presented with optimum characteristics and is suitable for agricultural purpose. The ﬁnal product coming out from an in-Vessel reactor seems to mature faster than the product from the windrow system and is presented with a better soil conditioner. Ó 2010 Elsevier Ltd. All rights reserved.
Article history: Received 3 February 2010 Received in revisedform 6 May 2010 Accepted 10 May 2010
Keywords: Fenton Compost Olive mill wastewater Olive oil solid residue
1. Introduction Olive oil production is considered one of the oldest agricultural industries in the Mediterranean countries. Approximately 1.8 Â 106 t of olive oil is produced annually worldwide where the majority of it is produced in the Mediterranean basin. The average amount of olivemill wastewater (OMW) produced during the milling process is 1.2–1.8 m3 tÀ1 of olives. OMW resulting from the production processes in the Mediterranean region surpasses 30 million per year (El-Gohary et al., 2009). The treatment of liquid wastes produced from olive oil production is still a major challenge facing this industry. The main problem is attributed to its dark color, high organic contentand toxicity which are due to the presence of phenolic compounds. COD values of OMW may reach 150 g LÀ1, most of which are in a particulate form while suspended solids up to 190 g LÀ1 have been recorded (Canizares et al., 2007). Olive oil extraction is among the most traditional agricultural industries in Cyprus and it has always been, and is among the importance for the national economy. Thetotal area under olive cultivation is about 7400–8000 ha with about 2.2– 2.7 million productive trees. It is estimated that olive trees hold 44.7% of the total agricultural area under permanent crops. This represents approximately 5.6% of the country’s cropped area
* Corresponding author. E-mail addresses: email@example.com, firstname.lastname@example.org, email@example.com (A.A. Zorpas),firstname.lastname@example.org (C.N. Costa). URLs: http://www.envitech.org (A.A. Zorpas), http://www.cut.ac.cy (C.N. Costa). 0960-8524/$ - see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.biortech.2010.05.030
and contributed 2.7–2.9% of total agricultural output. Olive mill wastewaters (OMW) constitute a serious environmental problem in the Mediterranean Sea region due to theunique features associated with this type of agro-waste, namely seasonal and localized production (typically between October and March), low ﬂowrates (between 10 and 100 m3 dÀ1) and high and diverse organic load (Gotsi et al., 2005). The quantity of olive oil mill vegetation and washing efﬂuents (commonly referred to as olive mill efﬂuents or wastewaters (OME or OMW) generated, and consequently the...