MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
Edited by Prof. Dr. Jose A. Perales Vargas-Machuca joseantonio.perales@uca.es Prof. Dr. Manuel A. Manzano Quiñones manuel.manzano@uca.es Environmental Technology Research Group University of Cádiz Spain
Cádiz, July 2002
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE DETERMINING CRITERIA FOR THE OBJECTIVES NO
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OIL ON SHORE
YES
IS THERE A SAFE ACCESS?
Next NO IS FREE OIL PRESENT? PROTECT THREATENED AREAS. MECHANICAL RECOVERY FROM THE SEA WHEN THE OIL MOVES FROM THE COAST
YES RECONSIDERER OTHER OBJECTIVES?
YES
IS THERE A THREATENED SITE?
OK
IS IT A HIGH ENERGY COAST?
NO
YES YES
IS IT A SITE OF SPECIAL CONCERN? (AMENITY BEACH OR ECOLOGICAL IMPLICATIONS) NO
NO YES
NO
NO NON BIOLOGICAL IN SITU TECHNIQUES
COMPLETED OBJECTIVES?
YES
IS A NON BIOLOGICAL IN SITU TECHNIQUE FEASIBLE AND EFFECTIVE ?
YES
CAN WE WAIT UNTIL WARMER SEASONS?
NO NO
IS AERATION FEASIBLE?
NO EROSION RISK? YES ON-SITE CHEMICAL PHYSICAL TREATMENT EX SITU BIOLOGICAL TECHNIQUES
YES IS AN EX SITU TECHNIQUE FEASIBLE AND EFFECTIVE?
NO
NO
IS THE OIL BIODEGRADABLE? YES
IS THE TEMPERATURE ADEQUATE? YES
NO
IS OXYGEN CONCENTRATION ADEQUATE?
OK IN-SITU BIOSTIMULATION AERATE BY ADDITION OF OXYGEN
YES
NO OBJECTIVES COMPLETED?
MONITORING
IN-SITU BIOSTIMULATION ADD NUTRIENTS WITH NUTRIENTS
YES NATURAL ATTENUATION AND MONITORING
NO
YES
YES
YES
NO
IS THE OIL BIODEGRADABLE?
NO
IS THERE OTHER LIMITING FACTOR?
NO
IS NUTRIENT CONTENT SUFFICIENT? YES
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
OIL ON SHORE
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
DETERMINING CRITERIA FOR THE OBJECTIVES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS THERE A SAFE ACCESS?
YES
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NO
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS FREE OIL PRESENT?
YES
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NO
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
RECONSIDER OTHER OBJECTIVES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS THERE A THREATENED SITE?
YES
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NO
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
PROTECT THREATENED AREAS. MECHANICAL RECOVERY FROM THE SEA WHEN THE OIL MOVES FROM THE COAST
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS IT A HIGH ENERGY COAST? YES
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NO
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS IT A SITE OF SPECIAL CONCERN ?
YES
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NO
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS THE OIL BIODEGRADABLE ? NO
YES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS A NON BIOLOGICAL IN-SITU TECHNIQUE FEASIBLE AND EFFECTIVE? NO
YES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
NON BIOLOGICAL IN-SITU TECHNIQUES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
COMPLETED OBJECTIVES? NO
YES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
TREATMENT FINISHED
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS THE TEMPERATURE ADEQUATE? NO
YES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
CAN WE WAIT UNTIL WARMER SEASONS? NO
YES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS OXYGEN CONCENTRATION ADEQUATE? NO
YES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS AERATION FEASIBLE? NO
YES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IN-SITU BIOREMEDIATION BY OXYGEN ADDITION TECHNIQUES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS AN EX-SITU TECHNIQUE FEASIBLE AND EFFECTIVE? NO
YES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
EROSION RISK? NO
YES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS THE OIL BIODEGRADABLE ? NO
YES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
ON SITE CHEMICAL-PHYSICAL TREATMENT
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
EX-SITU BIOLOGICAL TECHNIQUES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS NUTRIENT CONTENT SUFFICIENT ? NO
YES
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IN-SITU BIOREMEDIATION BY NUTRIENT ADDITION TECHNIQUES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
MONITORING
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
COMPLETED OBJECTIVES? NO
YES
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MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
IS THERE OTHER LIMITING FACTOR ? NO
YES SEE NOTE
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Explanations
MARINE BIOREMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE GUIDE
NATURAL ATTENUATION AND MONITORING
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Oil on Shore This is a bioremediation guide only for oil and marine environments. On the other hand, bioremediation has been considered as an effective technology only in the sediment. Therefore, the starting point of the flowchart will be the presence of crude oil on the shore.
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Determining Criteria for Objectives The first consideration has to be the establishment the reason for bioremediation, i.e., ecological and economic implications because they will determine not only the technology to be used but also the required final oil concentration
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Is there safe access? In occasions and due to the particular morphology of the coast, for example wave-cut rock platforms it becomes very difficult or practically impossible to carry out bioremediation technologies. In this situations the only solution is natural attenuation and monitoring.
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Is free oil present? Bioremediation is considered the second phase of the plan, first being the removal of free oil. Therefore, if the shoreline is saturated with oil it is first necessary and very important to remove it. The presence of free oil on shoreline can be easily noticed by simple visual observation.
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Is there a threatened site? Before consider which clean-up technologies should be used, it is necessary to know if the oil spill is still spreading to others non contaminated areas. In this case, the first action should be to confine the oil.
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Is it a high energy coast? It is very important to differentiate between high and low energy coasts in order to determine what type of bioremediation technology is the most appropriate for each case. Generally in high energy coasts in-situ bioremediation technologies are not feasible because the sediments are likely to be removed by tidal action. In order to have information about the classification of the offshore related with its energy, geomorphologic cartography is a very useful tool. Back to the previous slide
Is it a site of special concern? (Amenity beach or ecological implications) One important question is how long will clean-up take. Related to this aspect, in-situ bioremediation technologies are long-term clean-up technologies, so they can not be selected when in a hurry are which is the case with economic (amenity beach) or ecological reasons (high ecological value zone). Nevertheless, it is necessary to keep in mind that as fast is a clean-up technology, higher is the environmental impact that its application could provoke on the contaminated compartment, so a balance between both possibilities, impact from the oil spill and impact from carry out the cleaning process, should be considered.
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Is oil biodegradable? Bioremediation is only applicable in significantly biodegradable oils. Far from being a homogeneous substance, crude oil is a complex mixture of thousands of different chemical compounds. Since components of petroleum degrade at different rates, it is difficult and misleading to speak in terms of an overall biodegradation rate. Biodegradation rates are typically highest for the saturates, followed by the light aromatics, with high-molecular-weight aromatics, asphaltenes, and resins exhibiting extremely low rates of degradation. As a spill weathers, its composition changes: the light aromatics and light alkanes dissolve or evaporate rapidly and are metabolised by microorganisms. The heavier components that are harder to degrade remain. Therefore no crude oil is subject to complete biodegradation, and claims that all of a light oil or more than 50 percent of a heavy oil can be biodegraded in days or weeks are highly suspect.
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Is the temperature adequate? At low temperature, the rate of hydrocarbon metabolism by microorganisms decreases. Also, lighter fractions of petroleum become less volatile, thereby leaving the petroleum constituents that are toxic to microbes in the water for a longer time and depressing microbial activity. Petroleum also becomes more viscous at low temperature. Hence, less spreading occurs and less surface area is available for colonisation by microorganisms. Therefore, a minimum temperature is required in order to promote such bio-reactions. This minimum temperature is between 5 and 10ยบC, depending on the latitude.
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Can we wait until warmer seasons? In temperate regions, seasonal changes in water temperature affect the rate of biodegradation, but the process continues yearround.
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Is oxygen concentration adequate? Oxygen is one of the most important requirements for microbial degradation of hydrocarbons. When oxygen is not available, the rates of biodegradation decrease. Thus, oil that has sunk to the sea floor and been covered by sediment takes much longer to degrade. Oxygen availability there is determined by depth in the sediment, height of the water column, and turbulence. Low-energy beaches and fine-grained sediments may also be depleted in oxygen; thus, the rate of biodegradation may be limited in these areas. There are two organoleptic indicators that can be easily used to establish if a sediment is under anaerobic or aerobic conditions. One is the colour of the sediment, which is black under anaerobic conditions due to formation of metallic sulfides. Nevertheless, this indicator could not be very useful because the colour of the oil. The second indicator is the odour of the anaerobic sediment, which is nauseating due to emissions of hydrogen sulfide acids, ammonia and intermediates from degradation of organic compounds with nitrogen and sulfur. Back to the previous slide
Is the nutrient content sufficient? Nutrients such as nitrogen and phosphorus play a critical role in limiting the rate of biodegradation in marine waters. Several studies have shown that an inadequate supply of these nutrients may result in a slow rate of biodegradation. Although petroleum is rich in the carbon required by microorganisms, it is deficient in the mineral nutrients necessary to support microbial growth. Marine and other ecosystems are often deficient in these substances because non-oil degrading microorganisms (including phytoplankton) consume them in competition with the oil degrading species. Also, phosphorus precipitates as calcium phosphate at the pH of seawater. The nutritional requirements of carbon to nitrogen is 10:1 and carbon to phosphorus 30:1.
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Monitoring For proper application of the technology, there is a need for monitoring programmes to quantify intrinsic rates of oil loss and degradation, demostrate treatment efficacy and identify operational endpoint. A major obstacle is heterogeneity within the natural environment. Absolute levels of contamination can vary widely over a site and simple estimates of biodegradation based on sequential samples can be confounded by this heterogeneity, unless large number of samples are taken. This problem can be resolved by the normalisation of data to conserved markers such us hopanes and chrysenes found within the oil. Nevertheless this solution has high costs and are time consuming. Other possibilities include reliable microbial response and ecotoxicologycal monitoring protocols to verify efficacy for toxicity reduction over that of no treatment.
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Are there other limiting factors? In addition to the nutrients just cited, some organisms may also need organic nutrients. Required organic nutrients, know as growth factors, are compounds needed by organisms as precursors or constituents of organic cell material that cannot be synthesised from other carbon sources. Although growth factors requirements differ from one organism to another, the major growth factors fall into the follow three main classes: amino acids, purines and pyrimidines and vitamins.
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Are there other limiting factors? Note: If at the previous question about if the oxygen concentration is adequate the answer was not, then it has to be considered that the oxygen is a limiting factor.
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On-site Chemical-Physical Treatment The on-site treatments consists on those ex-situ technologies where the removed sediment is located nearby the contaminated area but in a zone not influenced by the tide.
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Erosion Risk If an ex-situ bioremediation technology is applied, the removal of the original sediments can affect the littoral drift, because it causes changes in the granuloumetry of the sediment
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