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Insights into Biotechnological Approaches for Treatment of Petroleum Refinery Effluents
Published in Gunjan Mukherjee, Sunny Dhiman, Waste Management, 2023
Mechanical barriers involve skimmers, which are used for removal of oil slicks (i.e., floating oil) from sea water surface before reaching surrounding coastlines. They are classified according to the area in which they are used like inshore, offshore, rivers, and superficial waters. Skimmers usually exist in the form of belts, disks, drums, mops, and floating suctions with a particular surface to facilitate adherence to spilt oil. Skimmers are divided into four classes depending upon the operating theory and mechanism. For instance, weir skimmers are based on gravity, oleophilic skimmers are based on oil adhesion to a moving surface, mechanical skimmers are based on physical oil picking by catches, scoops, belts, and eventually vacuum skimmers are based on pumps and suctions (Speight 2020). A skimmer’s effectiveness is determined by how quickly it gathers spilt oil, and quantities of water being collected. The obtained oil from skimmers is temporarily preserved in storage tanks. Skimmers are efficient in physical removal of oil slicks from the environment, allowing the recovered oil to be recycled and properly disposed of, hence reducing the subsequent environmental impacts. Current waves and wind influence the efficiency of spilt oil collection and retrieving. An experienced response team has to clearly understand the hydrodynamic processes.
Introduction to Oil Spills and their Clean-up
Published in Ozcan Konur, Petrodiesel Fuels, 2021
Skimmers are mechanical devices designed to remove floating oil from a water surface. They vary greatly in size, application, and capacity, as well as in recovery efficiency. They are classified according to the area where they are used, for example, inshore, offshore, in shallow water, or in rivers, and by the viscosity of the oil they are intended to recover. Most function best when the oil slick is relatively thick. The oil must, therefore, be collected in booms or against a shoreline or floating ice before skimmers can be used effectively. The skimmer is placed wherever the oil is most concentrated in order to recover as much oil as possible. Weather conditions at a spill site have a major effect on the efficiency of skimmers. Depending on the skimmer type, most will not work effectively in waves greater than 1 m in height or in currents > 0.5 m/s. Most do not operate effectively in water with ice or debris such as branches, seaweed, and floating waste. Some have screens around the intake to prevent debris or ice from entering, conveyors or similar devices to remove or deflect debris, and cutters to deal with seaweed. Very viscous oils, tar balls, or oiled debris can clog the intake or entrance and make it impossible to pump oil from the skimmer’s recovery system. Figure 42.2 shows a boom and a skimmer recovering oil.
Emergency Treatment of Marine Oil Spill
Published in Lin Mu, Lizhe Wang, Jining Yan, Information Engineering of Emergency Treatment for Marine Oil Spill Accidents, 2019
Lin Mu, Lizhe Wang, Jining Yan
The underwater pumping type skimmer is also called the underwater suction or weir type skimmer. Weir skimmer is generally composed of floatation, oil collector, edge height adjustment device, drain pump, oil suction pump and power system. It appears more like a funnel. The bottom is a drain pump, and the upper part is an oil suction pump. The suction inlet is deep into the oil slick layer, and the funnel is fixed on floatation for buoyancy force adjustment. The drain pump continuously absorbs water from the funnel during operation and drains it out from the bottom of the funnel to lower the water level in the funnel. The seawater and oil slick continuously enter from the upper part so that the oil layer in the funnel thickens and the oil suction pump sucks the oil and transfers it to an oil collector.
Oil spill cleanup by raw cellulose-based absorbents: a green and sustainable approach
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Minh Quang Chau, Tan Trung Truong, Anh Tuan Hoang, Tri Hieu Le
The use of NCAs combined with other advanced techniques in the cleanup of the oil spill has been experienced, and it has shown high efficiency. In the case of a relatively calm water surface, a mechanical device such as a skimmer can be used to collect oil spills. Nonetheless, the real condition is not always ideal; the spilled oils are thus absorbed into the porous structure of NCAs before skimmers are in place resulting in the likelihood of the reduction in spreading spilled oils or the formation of oil-water emulsion. Moreover, the use of NCAs is expected to reduce the spilled oils that are flowed to skimmers. This may interfere locally with the normal operation of skimmers (Fingas 2012). In a study of Cao et al. (Cao et al. 2018), high efficiency of up to 93% was reported while using a centrifuged filter in combination with the cattail fiber assembly to recover diesel oil. In the application of absorbents for floating booms that are utilized to limit the spreading of oils on the water surface, the absorbents have been shown to enhance the effectiveness in collecting spill oils. In experiments, they were operated in two ways: (i) – Directly placed onto spilled oil layers (Hubbe et al. 2013), and (ii) – Paired with booms to form “sorbent booms”. In recent years, the development of bacteria that can decompose oil has been paid much attention to. Therefore, a method of using bacteria-supporting nutrients which is incorporated into NCA may be a promising solution because cellulose is considered as a food or enzyme source keeping the bacteria (Sai, Fu, and Xing et al. 2015). It is worth mentioning that how and what should be done for the cultivation, harvesting, and storage of cellulose-based products to obtain the highest productivity should be closely associated with a necessity to evaluate their efficiency of oil absorption under realistic conditions with the impacts of the wave, wind, temperature, sea conditions, and degree of oil spillage.