Journal of Hazardous Materials 110 (2004) 113–118 A new procedure for treatment of oily slurry using geotextile filters M.B. Mendonça a,∗ , M.C. Cammarota b , D.D.C. Freire b , M. Ehrlich c a Terrae Engenharia, Avenida Almirante Ari Parreiras, 649 Icarai, Niteroi, Rio de Janeiro, Brazil b School of Chemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil c COPPE, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil Available online 6 May 2004 Abstract A new procedure to mitigate the environmental impacts and reduce the cost of disposal of oil slurry is present in this paper. Waste from the petroleum industry has a high environmental impact. Systems for oil–water separation have been used to mitigate the contamination potential of these types of effluents. At the outlet of these systems, the oil is skimmed-off the surface, while the slurry is removed from the base. Due to the high concentration of contaminants, the disposal of this slurry is an environmentally hazardous practice. Usually this type of waste is disposed of in tanks or landfills after removal from the industrial plant. Basically, the proposed procedure utilizes drying beds with geotextile filters to both reduce the water content in the slurry and obtain a less contaminated effluent. Laboratory tests were carried out to simulate the drying system. Four types of filters were analyzed: two non-woven geotextiles, one woven geotextile, and a sand filter. © 2004 Elsevier B.V. All rights reserved. Keywords: Oil; Oily slurry; Drying bed; Geotextile; Filtration 1. Introduction Our energy needs are heavily dependent on oil and its derivatives, the waste that is produced in fuel production processes is now concern, but until recently received lit- tle attention. These waste materials include sludge and slurry from oil, and especially from lubricants. Some types of sludge/slurry may be reused, recycled, incinerated, co-processed, and even treated. However, even in developed countries, this sludge/slurry is stored in tanks or discharged into landfills almost arbitrarily, since there is no specific environmental legislation on the matter. Oily effluents produced in the petroleum production chain are treated primarily using traditional oil–water sep- aration systems (OWS) to minimize the oil levels and allow the oil to be recovered and the effluent treated. The equipment that is usually used for this type of treatment is the American Petroleum Institute (API) oil–water separa- tor. This is basically a rectangular tank through which the effluent flows at low speed; therefore, laminar flow predom- inates. Oil droplets rise, accumulate at the surface and are ∗ Corresponding author. Tel.: +55-213-8780038; fax: +55-213-8780038. E-mail address: marcos@terrae.com.br (M.B. Mendonça). skimmed-off. The solids settle to the bottom of the tank, are channeled into a ditch and are pumped out. Other types of gravity-based separators exist that are an improvement on the API type, such as the parallel plate interceptor. This sep- arator is filled with plates that accelerate the formation of large oil drops at the surface, improving the effectiveness of oil separation and reducing the size of the separator. While an API separator can supply effluents with 40–150 ppm oil, the parallel plate separator can supply effluents with 20 ppm oil. However, the API separator is much cheaper to buy and operate, which explains why it is often preferred [1]. Regardless oil levels in the wastewaters and water content in the disposal slurry remain high. A method for treating oily slurry is presented in this pa- per. The proposed method consists of a dehydration process using drying beds with geotextile filters to separate water from sludge. The aim is to obtain water with a lower oil con- tent, which makes further treatment easier; and, to obtain dehydrated slurry that can be reused in the co-processing of the cement or ceramics industry. Also, reducing the water content of the slurry enables its use as a source of energy. Even if the slurry could not be used in the co-processing, the dehydration would reduce the volume of the final waste to be discharged, minimizing the environmental impacts and costs involved. 0304-3894/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2004.02.044