Petroleum Hydrocarbon Removal from Wastewaters: A Review

Abstract

Oil pollutants, due to their toxicity, mutagenicity, and carcinogenicity, are considered a serious threat to human health and the environment. Petroleum hydrocarbons compounds, for instance, benzene, toluene, ethylbenzene, xylene, are among the natural compounds of crude oil and petrol and are often found in surface and underground water as a result of industrial activities, especially the handling of petrochemicals, reservoir leakage or inappropriate waste disposal processes. Methods based on the conventional wastewater treatment processes are not able to effectively eliminate oil compounds, and the high concentrations of these pollutants, as well as active sludge, may affect the activities and normal efficiency of the refinery. The methods of removal should not involve the production of harmful secondary pollutants in addition to wastewater at the level allowed for discharge into the environment. The output of sewage filtration by coagulation and dissolved air flotation (DAF) flocculation can be transferred to a biological reactor for further purification. Advanced coagulation methods such as electrocoagulation and flocculation are more advanced than conventional physical and chemical methods, but the major disadvantages are the production of large quantities of dangerous sludge that is unrecoverable and often repelled. Physical separation methods can be used to isolate large quantities of petroleum compounds, and, in some cases, these compounds can be recycled with a number of processes. The great disadvantage of these methods is the high demand for energy and the high number of blockages and clogging of a number of tools and equipment used in this process. Third-party refinement can further meet the objective of water reuse using methods such as nano-filtration, reverse osmosis, and advanced oxidation. Adsorption is an emergency technology that can be applied using minerals and excellent materials using low-cost materials and adsorbents. By combining the adsorption process with one of the advanced methods, in addition to lower sludge production, the process cost can also be reduced.

The Influence of Self-Heating Iron on the Thermal, Mechanical, and Swelling Properties of PDMS Composites for Organic Solvents Removal

“…The composites that hold solid metal fillers exhibit a range of outstanding properties, such as lower density, low cost, and simple fabrication [ 33 ]. These properties, together with the magnetic character, render the composites suitable for application in oil collection [ 34 , 35 , 36 ]. Magnetic character is also crucial for reusing and separating the composites from the medium simply by using a magnetic field.…”

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“…The observation here is similar to that made by Edori, et al [23] in the Edagberi River were total petroleum hydrocarbons concentration was as low as 2.47858±0.119mg/l in the month of December. The evaporation of the lighter fractions of total petroleum hydrocarbons is the fastest known physical process that influences the reduction of such in the aquatic environment [24]. The rate at which this occur can also be influenced by such factors as wind velocity, temperature, surface water characteristics of the river also known as turbulence [25], which are prevalent environmental conditions during the month of December in the area.…”

Impact of the Oxidant Type on the Efficiency of the Oxidation and Removal of Iron Compounds from Groundwater Containing Humic Substances

“…In the conducted tests, the lowest efficiency of removing iron compounds from groundwater after oxidation with hydrogen peroxide ( Figure 6 and Figure 8 ) could have been the result of using too low a dose of hydrogen peroxide and too high a pH value of water, which determines the form of the presence of the oxidant and different reaction mechanisms in acid and alkaline environments. According to literature reports [ 40 ], the use of appropriate oxidation parameters with Fenton’s reagent (pH = 4; Fe(II): H 2 O 2 = 1:5) ensures 90% removal efficiency from DOC with molecular weight > 0.5 kDa. However, this method is not commonly used for purifying water intended for human consumption due to the need to acidify the water and remove the Fe(III) ions formed.…”

“…The produced • OH after that oxidizes the organic substances [ 39 ]. According to literature reports [ 40 ], pH is a determinant factor in the Fenton process. At pH values in the range of 2.0–4.0, the highest concentration of Fe 2+ occurs, and hydrogen peroxide is most stable at pH levels in the range of 3.0–4.0.…”