Cleanup Operations Research Articles

Factors affecting fill removal from horizontal well during colied tubing cleanout operation

Coiled Tubing (CT) is extensively used in oil industry to clean the wellbore to increase the productivity of oil/gas well by removing the fill/sand downhole. Well cleanup operation for low bottom hole pressure is problematic and common cleanout fluids are not effective as a circulation fluid due to severe pressure losses and low suspension capability. The use of foam as cleaning agent has become more popular due to its low density and high viscosity. The objective of this paper is to investigate the factor effecting on fill concentration and pressure loss during horizontal wellbore cleanup operation at different CT/Annulus diameter ratios using Herschel Buckley viscosity model. Results showed that foam quality has the significantly high effect on fill concentration as compared to foam velocity. It is noticed that diameter ratio has high effect on particle removal when foam quality is 70%. Surprisingly, it is found that the effect of diameter ratio on fill concentration decreases when foam quality is 90%.

Radiological assessment in case of an incident at the hot cells clean-up

The clean-up and decontamination of the hot cells will be performed in the second phase of the WWR-S research reactor decommissioning. Identification of possible incidents or accidents is the key element in radiological assessment and prevention. As major incident it was considered a fire burst that occurred during the progress of the clean-up operations. The postulated incident has, as a consequence, thick smoke generation from the burned radioactive material and the dispersion of this material in the environment through the technological ventilation system and the evacuation chimney. From the performed analysis it can be seen that in the case of an incident to the reactor hot cells, an operator engaged in intervention operations could take an effective dose of 5.29 Sv per event, coming from both external and internal exposure. Such an incident, if it happens, would be classified of level 3 on the INES scale.

Managing legacy waste in the presence of cultural heritage at Wilkes Station, East Antarctica

ABSTRACTThe Antarctic Treaty has been the principal governing force in Antarctica since 1961. The Protocol on Environmental Protection to the Antarctic Treaty (Madrid Protocol) requires that all past and present work and waste-disposal sites are cleaned up unless doing so would cause greater environmental damage or the site is considered to be a monument of significant historical importance. Despite this requirement, legacy waste issues remain unresolved in parts of Antarctica. Clean-up operations in Antarctica are complicated by a combination of restricted access, extreme weather, financial limitations and logistical constraints. Further complications arise at sites such as Wilkes Station, where the requirement for clean-up coexists with the desire to preserve potentially valuable heritage items.Several buildings and artefacts with potential heritage value remain at Wilkes Station. However, Wilkes Station is not officially designated as a historic site or monument under the Antarctic Treaty, nor is it a national or world heritage place under Australian domestic legislation. Consequently the buildings and relics at Wilkes Station are afforded little protection under the existing relevant domestic and international legislative frameworks.This paper uses Wilkes Station as a case study of the complexities associated with conducting clean-up operations at contaminated sites with informal heritage value in Antarctica. The legislative and environmental considerations surrounding clean-up operations at Wilkes Station are also investigated. Furthermore, we argue the importance of a multi-disciplinary approach to operations which facilitate the clean-up of legacy waste and preservation of the potential heritage values at Wilkes. Finally, we recognise that the complexities discussed in this paper have wider applicability and we investigate the relevance of these issues to other Antarctic contaminated sites with formal or informal heritage value.

A probabilistic model estimating oil spill clean-up costs – A case study for the Gulf of Finland

Existing models estimating oil spill costs at sea are based on data from the past, and they usually lack a systematic approach. This make them passive, and limits their ability to forecast the effect of the changes in the oil combating fleet or location of a spill on the oil spill costs.In this paper we make an attempt towards the development of a probabilistic and systematic model estimating the costs of clean-up operations for the Gulf of Finland. For this purpose we utilize expert knowledge along with the available data and information from literature. Then, the obtained information is combined into a framework with the use of a Bayesian Belief Networks. Due to lack of data, we validate the model by comparing its results with existing models, with which we found good agreement.We anticipate that the presented model can contribute to the cost-effective oil-combating fleet optimization for the Gulf of Finland. It can also facilitate the accident consequences estimation in the framework of formal safety assessment (FSA).

Stability of solid-phase selenium species in fly ash after prolonged submersion in a natural river system

Selenium (Se) chemistry can be very complex in the natural environment, exhibiting different valence states (−2, 0, +4, +6) representing multiple inorganic, methylated, or complexed forms. Since redox associated shifts among most of known Se species can occur at environmentally relevant conditions, it is important to identify these species in order to assess their potential toxicity to organisms. In June of 2009, researchers from the US Army Engineer Research & Development Center (ERDC) conducted investigations of the fly ash spilled 6months previously into the Emory River at the TVA Kingston Fossil Plant, TN. Ash samples were collected on site from both the original ash pile (that did not move during the levee failure), from the spill zone (including the Emory River), and from the ash recovery ditch (ARD) containing ash removed during dredging cleanup operations. The purpose of this work was to determine the state of Se in the spilled fly ash and to assess its potential for transformation and resultant chemical stability from its prolonged submersion in the river and subsequent dredging. Sequential chemical extractions suggested that the river environment shifted Se distribution toward organic/sulfide species. Speciation studies by bulk XANES analysis on fly ash samples showed that a substantial portion of the Se in the original ash pile had transformed from inorganic selenite to a mixture of Se sulfide and reduced (organo)selenium (Se(-II)) species over the 6-month period. μ-XRF mapping data showed that significant trends in the co-location of Se domains with sulfur and ash heavy metals. Ten-d extended elutriate tests (EETs) that were bubbled continuously with atmospheric air to simulate worst-case oxidizing conditions during dredging showed no discernible change in the speciation of fly ash selenium. The enhanced stability of the organo- and sulfide-selenium species coincided with the mixture of the ash material with humic materials in the river, corresponding with notable shifts in the ash carbon- and nitrogen-functionality.

Nanoscience and Nanotechnology: Cracking Prodigal Farming

Nano-science coupled with nano-technology has emerged as possible cost-cutting measure to prodigal farming and environmental clean-up operations. It has ushered as a new interdisciplinary field by converging various science disciplines, and is highly relevant to agricultural and food systems. Environmental Protection Agency of USA defined nanotechnology as the understanding and control of matter at dimensions of roughly 1-100 nm, where unique physical properties make novel applications possible. By this definition all soilclays, many chemicals derived from soil organic matter (SOM), several soil microorganisms fall into this category. Apart from native soil-materials, many new nanotech products are entering into soil system, some of which are used for agricultural production and some others for many other purposes. Nano-science (also nanotechnology) has found applications in controlling release of nitrogen, characterization of soil minerals, studies of weathering of soil minerals and soil development, micro-morphology of soils, nature of soil rhizosphere, nutrient ion transport in soil-plant system, emission of dusts and aerosols from agricultural soil and their nature, zeoponics, and precision water farming. In its stride, nanotechnology converges soil mineralogy with imaging techniques, artificial intelligence, and encompass bio molecules and polymers with microscopic atoms and molecules, and macroscopic properties (thermodynamics) with microscopic properties (kinetics, wave theory, uncertainty principles, etc.), to name a few. Some of the examples include clinoloptolite and other zeolite based substrates, and Fe-, Mn-, and Cusubstituted synthetic hydroxyapatites that have made it possible to grow crops in space stations and at Antarctica. This has eliminated costs of repeated launching of space crafts. A disturbing fact is that the fertilizer use efficiency is 20-50 percent for nitrogen, and 10-25 percent for phosphorus (<1% for rock phosphate in alkaline calcareous soils). With nanofertilizers emerging as alternatives to conventional fertilizers, build ups of nutrients in soils and N at ur e P re ce di ng s : h dl :1 01 01 /n pr e. 20 09 .3 20 3. 1 : P os te d 29 A pr 2 00 9 thereby eutrophication and drinking water contamination may be eliminated. In fact, nanotechnology has opened up new opportunities to improve nutrient use efficiency and minimize 1 Paper presented at the International Symposium on Natural Resource Management held on 19-20 December 2008 at Jaipur, India (Accepted for publication by PROM Society) costs of environmental protection. It has helped to divulge to recent findings that plant roots and microorganisms can directly lift nutrient ions from solid phase of minerals (that includes so-called susceptible (i.e., easily weatherable, as well as non-susceptible minerals).

Mental Health in Residents 1.5 Years After the Hebei Spirit Oil Spill

Background: The assessment of the acute-phase mental health of the residents in the oil spill area showed a high degree of risk. Aims: The study intends to analyze the correlation between the damage of oil spill and mental health of the residents in the oil spill area, and identify the status of residents’ mental health according to the distance from the point of accident and the number of day for clean-up operation. Methods: The community survey of 9,246 residents was conducted 1.5 years after the oil spill accident. PTSD, depression, stress and anxiety were performed using the Posttraumatic Diagnostic Scale, Center for Epidemiologic Studies Depression Scale, Psychological Wellbeing Index, State-Trait Anxiety Inventory, respectively. Results: After adjusting for the covariates, the risks of having the symptoms of PTSD (OR 2.80, OR 3.24), depression (OR 1.13, OR 1.95), stress (OR 1.22, OR 1.36), and/or trait-anxiety (OR 1.52, OR 1.64) increased significantly according to the distance from the oil spill point to the residence and the total number of days of clean-up of participation.. conclusions: A higher rate of symptoms of mental health was found as the residents live closer to the accident point, and participate in longer clean-up work duration. it necessary to monitor the long-term mental health in residents

Impairments to Higher Mental Functions and Cognitive Auditory Evoked Potentials in Chernobyl Clean-Up Workers

Complex investigations including neuropsychological studies and analysis of cognitive auditory evoked potentials using a three-stimulus oddball paradigm were performed in 10 participants in the Chernobyl power station clean-up operation and 10 healthy subjects. Impairments to higher mental functions, including exhaustion, fatigue, and decreases in auditory-verbal and visual memory and motor functions, were seen in clean-up workers. Decreases in the amplitudes of all EP components (N1, N2, and P3) were seen in clean-up workers for all stimuli in both experimental situations (hearing all stimuli and counting target stimuli) as compared with normal. The latent periods (LP) of the N1 and N2 EP components were shorter in clean-up workers, while that of P3 was longer. The greatest differences in LP between groups were seen in the frontal areas of the left hemisphere for N1 and P3 and in the right hemisphere for N2. Correlation analysis between EP and neuropsychological investigations showed that changes in the LP of N1 correlated with impairments to short-term memory and postural praxis of the right hand, while changes in the LP of N2 correlated with impairments to long-term memory and postural praxis of the left hand. Changes in the LP of P3 correlated with impairments to complex cognitive activity. Thus, complex investigations revealed impairments to the perception, processing, and analysis of information, combined with reduced inhibition and an “uneconomical” type of responding, accompanied by impairments to higher mental functions in clean-up workers as compared with healthy subjects of the same age. Impairments seen in clean-up workers were similar to those seen in elderly people and support the hypothesis of early cerebral aging in clean-up workers induced by low doses of radiation.

Fukushima leaks 18 times worse than first thought

New revelations from stricken plant’s operator add to claims that it cannot cope with clean-up operation.

Molecular tools for monitoring harmful algal blooms

The world's oceans cover 70 % of the Earth's surface, and their dominant populations, both numerically and biomasswise, belong to microscopic protists and prokaryotes. The marine phytoplanktons are major components of both groups and are, by definition, high dispersal taxa with large population sizes. Small photosynthetic organisms are responsible for the bulk of primary production in oceanic and neritic waters. Microalgae in marine and brackish waters of Europe regularly cause harmful effects, considered from the human perspective, in that they cause economic damage to fisheries and tourism. Cyanobacteria cause similar problems in freshwaters. These episodes encompass a broad range of phenomena collectively referred to as ‘harmful algal blooms’ (HABs). For adequate management of these phenomena, monitoring of microalgae is required. However, present day monitoring is time consuming and based on morphology as determined by light microscopy, which may be insufficient to give definitive species and toxin attribution. The public perception of harmful algal blooms is often that of eutrophication, where increased nutrient loading results in large biomass blooms, which have a consequent effect on water quality (anoxia) and the ecosystem through substantial alterations in both the benthic and pelagic ecology. All too often, events that directly or indirectly relate to increased nutrients, such as dead zones in the northern Gulf of Mexico, a huge clean-up operation following an Enteromorpha bloom off Qingdao in time for the Olympic sailing competition in 2008 or the knock-on effects of hydrogen sulphide toxicity caused by rotting vegetation following extensive growth of both macro- (Ulva, Brittany coast of France) and micro- (Phaeocystis, North Wales, UK) algae, find substantial room in the popular press. What is less well-known is that HABs caused by toxinproducing algae have not only a far more serious impact on the quality of life, but also they are entirely natural. Anthropogenic impacts on toxic HABs are limited to either their global spread through potential transport vectors, such as ballast water of ships, or because of alterations in the coastline resulting from the construction of harbours and marinas, particularly around the Mediterranean coast, which promotes the development of chronic dinoflagellate blooms, such as the paralytic shellfish poisoning (PSP) toxin producer Alexandrium.

Development of a Totally Enclosed Fan-Cooled Traction Motor

The intake of dust and dirt contained outside the air into the motor while driving causes the maintenance of dismantling and clean-up operation once every three years. Moreover, excessive acoustic noise during high-speed operation is produced by the cooling fan on the rotor. Totally enclosed airtight motor was developed not only to deal with the dust-intake problem but also to reduce acoustic noise. This motor eliminates the requirement of periodical dismantling and clean-up operation. Excessive noise of internal cooling fan was decreased by newly developed uneven pitch blade fan. Further, traction motor without external fan was developed by thermofluid simulation. Acoustic noise and temperature rise of these motor were measured and compared.

Application of Chicory as Corrosion Inhibitor for Acidic Environments

Summary During acidizing stimulation or cleanup operations, metal tubulars, downhole tools/valves, and surface lines are exposed to acidic fluids and are prone to corrosion. Because corrosion rates drastically increase in high-temperature wells, controlling corrosion is critical and must be dealt with carefully. In addition, corrosion protection is important for maintaining the integrity and long life of downhole tools installed in a well. Several corrosion inhibitors, such as quaternary ammonium compounds and propargyl alcohol-based compounds, have been effectively used in the industry. However, because of stringent environmental regulations, attention has focused on the development of new corrosion inhibitors that are environmentally benign. Food-grade products that are considered "green" chemicals have significant potential as corrosion inhibitors in the oil and gas industry. In this paper, application of chicory as a corrosion inhibitor for high-temperature and strong-acidic conditions is discussed. Chicory is a perennial bush plant available in many parts of the world. The root of the chicory plant can be roasted and ground for use as a coffee substitute or additive. Chicory is environmentally acceptable and, being of plant origin, is widely recognized as biodegradable in nature. This study shows that chicory can provide corrosion protection for alloys such as N-80, 13Cr-L80, and 1010 steel in the presence of either inorganic or organic acids at temperatures up to 250°F (121°C). Considering its performance and lack of toxicity issues, chicory has significant potential for acid corrosion-inhibition applications. The mixing procedure for preparing the blend, experimental setup and test procedure, and laboratory results of high-pressure/high-temperature (HP/HT) corrosion tests are discussed.

Heavy metals and As transport under low and high flows in the River Guadiamar three years after the Aznalcóllar tailings dam failure : implications for river recovery and management

This paper presents work from an on-going research programme examining the recovery of the Guadiamar River following the April 1998 Aznalcóllar tailings dam failure. Analysis of heavy metal (Cd, Cu, Pb and Zn) and As in surface waters, valley floor alluvium, overbank and suspended sediments are compared between six study reaches downstream of the dam, over five sampling periods. The principal aims of the paper are to examine the distribution of contaminants in sediments and river waters and their delivery downstream under low and high flows, and the implications for river channel recovery and management three years after the tailings dam failure. Results from a survey of Guadiamar alluvium carried out in January 1999 showed that, although clean-up operations were largely successful in restoring the affected area to pre-spill conditions, sediments continued to exceed intervention thresholds for the region. Residual contaminant levels were highest near the spill source, with isolated ‘hotspots’of elevated contamination throughout the affected area, superimposed on a general downstream decline in concentrations. In terms of contaminant mobility, surface water samples taken in May 99, under very low flows, have dissolved Cd, Cu and Zn concentrations which fail EC directive thresholds for surface water abstraction. Element concentrations are significantly lower for waters in January 1999, when controlled discharge from the Agrio reservoir was taking place. Under high flow conditions, sediment-associated contaminant transport is dominant for all elements discussed, accounting for between 91% (Cu) and 99% (Pb) of export yields. This has lead to the remobilisation of significant quantities of contaminants, particularly Pb and Zn, during post-spill floods. Overbank deposits, however, show a fall in contaminant concentrations, following successive flood events. This has been due to sediment mixing of contaminated and “clean” material. Dilution has so far maintained contaminant concentrations below intervention threshold limits in the lower reaches, thereby offering a cautiously optimistic prognosis for the sensitive wetlands of Doñana.

Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record‐Breaking Enterprise

On 20 April 2010, an explosion on the Deepwater Horizon oil drilling platform killed 11 people, and the subsequent blowout of the deepwater wellhead sparked one of the most costly oil spills in history. In the days and months that followed, researchers and disaster response crews flocked to the Gulf of Mexico to study, assess, and guide cleanup operations. In the AGU monograph Monitoring and Modeling the Deepwater Horizon Oil Spill: A Record‐Breaking Enterprise, editors Yonggang Liu, Amy MacFadyen, Zhen‐Gang Ji, and Robert H. Weisberg pull together the results of the state‐of‐the‐art rapid response research conducted during the Gulf oil spill. Here Eos talks to Yonggang Liu.

Methods of Pollution Removal After Tanker “Erika” Accident

Marine accident of the Maltese tanker Erika is the biggest environmental disaster ever to hit France. 12th of December 1999, on the way from Dunkerque (France) to Livorno (Italy), Erika broke in two and sank near the French coast, spilling around 20.000 tons of heavy fuel oil into the sea. About 11.000 tons of dangerous cargo, trapped inside the sunken wreck, presented a danger to the environment. Severe weather conditions prevented any offshore clean-up operations. Oil trapped inside the wreckage was pumped out, while the on-shore clean-up operations lasted for another two years. This accident had a direct impact on the economy of affected regions and resulted in numerous lawsuits against the ship owners, charterers and classification societies. This paper aims to provide an overview of oil spill pollution clean-up methods and technologies after the accident of tanker Erika.

The type and spatial distribution of past waste at the abandoned Wilkes Station, East Antarctica

ABSTRACTLegacy waste is a significant problem in Antarctica. This is particularly the case where waste generated on stations prior to the 1980s was incinerated, placed in landfill sites or disposed of at sea. Although several Australian Antarctic Division (AAD) reports from the 1980s recognise that there are contaminated sites at the abandoned Wilkes Station, there has been no systematic attempt to classify the waste or define the spatial scale of the problem, making development of strategic and systematic clean-up or preservation programmes difficult. This article reports on a project to classify the waste remaining on Clark Peninsula using categories listed in Annex III, Article 2 of the Madrid Protocol (1991). 536 sites with one or more waste items have been identified in nine categories that are based on the degree of waste hazard, recyclability, heritage value and waste management potential. Fuel drums, petroleum hydrocarbons waste and contaminated sediment occur at 38% of the sites. This waste includes around 1020 partially full fuel drums. Heritage items that illustrate expedition life at Wilkes occur at about 10% of the sites. Solid, non-combustible waste, including scrap metal, copper wire and pipe, and steel mechanical parts, occurs at 25% of the sites. Potentially hazardous or harmful waste including electrical batteries, plastics including fuel bladders, food remains, treated timber and containers containing persistent compounds occur at 28% of sites. Although hazardous substances, such as caustic soda, explosives and asbestos, occur at only 9% of the sites, these items represent significant contamination and heath issues for the sites and for visiting explorers. Any future clean-up operations will require more than just the physical removal of waste. Preservation, removal and treatment of various types of waste from Wilkes will be required as part of a multi-year, multi-strategy approach.

Community-based participatory research projects and policy engagement to protect environmental health on St Lawrence Island, Alaska

ObjectivesThis article synthesizes discussion of collaborative research results, interventions and policy engagement for St Lawrence Island (SLI), Alaska, during the years 2000–2012.MethodsAs part of on-going community-based participatory research (CBPR) studies on SLI, 5 discrete exposure-assessment projects were conducted: (a) a biomonitoring study of human blood serum; (b–d) 3 investigations of levels of contaminants in environmental media at an abandoned military site at Northeast Cape – using sediment cores and plants, semi-permeable membrane devices and blackfish, respectively; and (e) a study of traditional foods.ResultsBlood serum in residents of SLI showed elevated levels of polychlorinated biphenyls (PCBs) with higher levels among those exposed to the military site at Northeast Cape, an important traditional subsistence-use area. Environmental studies at the military site demonstrated that the site is a continuing source of PCBs to a major watershed, and that clean-up operations at the military site generated PCB-contaminated dust on plants in the region. Important traditional foods eaten by the people of SLI showed elevated concentrations of PCBs, which are primarily derived from the long-range transport of persistent pollutants that are transported by atmospheric and marine currents from more southerly latitudes to the north.InterventionsAn important task for all CBPR projects is to conduct intervention strategies as needed in response to research results. Because of the findings of the CBPR projects on SLI, the CBPR team and the people of the Island are actively engaging in interventions to ensure cleanup of the formerly used military sites; reform chemicals policy on a national level; and eliminate persistent pollutants internationally. The goal is to make the Island and other northern/Arctic communities safe for themselves and future generations.ConclusionsAs part of the CBPR projects conducted from 2000 to 2012, a series of exposure assessments demonstrate that the leaders of SLI have reason to be concerned about the health of people due to the presence of carcinogenic chemicals as measured in biomonitoring and environmental samples and important traditional foods.

The Impact of Sleep Complaints on Physical Health and Immune Outcomes in Rescue Workers

The present study evaluated the extent to which sleep assessed soon after a trauma predicted subsequent physical health and immune functioning in rescue workers. Participants included 159 men and women who performed rescue and clean-up operations at the site of a major airplane crash. One hundred twenty-eight participants were retained for a 1-year follow-up. Self-report measures of sleep quality and psychological distress were obtained within 2 months of the crash, and a physical health questionnaire was completed at 1-year follow-up. Natural killer cell number and cytotoxicity were assessed using blood samples collected from a subset of participants (n=51) at 1-year follow-up. After adjustment for sex, age, body mass index, and initial distress, initial sleep quality complaints were associated with more physical symptoms (β=.32; p<.001), poorer perceived health (β=-.27; p=.009), and increased healthcare utilization (β=.31; p=.003) on follow-up. In contrast, initial sleep quality was not associated with natural killer cell number (r=0.10; p=.55) or activity (r=0.02; p=.90). Change in sleep quality during the year after the crash was not a significant predictor of health or immune outcomes. These data suggest that poor sleep quality in the aftermath of trauma signals an increased risk for future adverse physical health outcomes and underscore the importance of addressing sleep complaints soon after trauma to mitigate negative impact on physical health.

Should I stay or should I go? An experimental study of health and economic government policies following a severe biological agent release

Extensive research has explored policy chal- lenges associated with preparing and responding to a large- scale biological release. A key component in recovery strategy development that has received less attention is the understanding of government policy influence on the impacted populations' migratory decisions. This study experimentally manipulates health and economic govern- ment policies during response and recovery to assess the extent to which public migration is contingent on the level of government intervention. Set immediately following a large- scale anthrax release in San Francisco, we use a five episode video scenario to describe details about the environmental impacts of the disaster, emergency response procedures, and clean-up operations. Within these video segments, the extent of government involvement in economic and health risk policies is manipulated. Using these manipulations as pre- dictors, we track how varying levels of government risk signals influence migration behavior at three distinct decision points during disaster recovery. In addition, two belief scales and two scales of emotion (affect) are included as predictors to explore the potential for their mediating role in explaining intentions to migrate. We find that the decision to migrate is highly context-sensitive, with each decision point showing a unique combination of significant predictors influencing decision making. At 19 days following the anthrax release, the health risk policy manipulation has both a direct and indirect effect on migration behavior. At 3 months, the influence of the health risk policy manipulation is mediated by beliefs, and at 1 year, only indirect effects associated with affect and beliefs influence migration.

Application of Modified Coir Fiber as Eco-friendly Oil Sorbent

Application of Modified Coir Fiber as Eco-friendly Oil Sorbent Lignocellulosic fibers are attractive materials due to its abundance nature, sustainability and biodegradability. They are economical and have low processing energy requirements. Modification of these fibers to make them hydrophobic may allow them to be used as sorbent in oil spill. Oil spills can damage the flora and fauna of the sea and have a great impact on economy and environment. In this study, coir fibers have been acetylated to impart hydrophobicity and increase the oil sorption capacity. The product so formed was characterized by FT-IR, TG, SEM and its degree of acetylation was also evaluated. The extent of acetylation was measured by weight percent gain. Studies indicate that a simple squeezing operation was sufficient to remove most of the oil sorbed by the fibers so that the sorbents can be recycled several times for oil spill clean-up. The results suggest that a total or partial substitution of commercial non biodegradable synthetic oil sorbents by natural sorbent materials like modified coir fibers could be beneficial in the oil spill clean-up operation for improving the efficiency of oil sorption.