The global use of petroleum hydrocarbons for energy and raw materials in various applications has increased with extensive release of a wide variety of contaminants into the environment, affecting soil, surface water and groundwater. The effect results to numerous health, ecological and environmental issues. However, treatment of contamination and pollution caused by petroleum hydrocarbons is a huge and laborious work. It involves several in situ or ex situ treatments comprising containment, separation and destruction which include biological, chemical, physico-chemical, thermal and heat, electric and electromagnetic, acoustic and ultrasonic treatment methods. These treatment methods involve several other techniques and strategies as listed in this review. The health risks pose by petroleum hydrocarbon pollution have driven scientists to research, develop and implement risk-based remediation strategies for restoration and reclamation of affected environments. To select the best treatment option for remediation, it is important to comprehend the nature, composition, properties, sources of pollution, type of environment, fate, transport and distribution of the pollutants, mechanism of degradation, interaction and relationships with microorganisms, the intrinsic and extrinsic factors affecting remediation. It helps to evaluate and predict the chemical behaviour of the pollutants with the short and long-term effects and mitigate the effects of pollution and limit exposure to the pollutants. Despite the available remediation options for petroleum hydrocarbon management and removal, sufficient and complete remediation can be implemented by adoption of proper approach derived from risk-based management procedure that can be practical, scientifically defensible, widely adapted, sustainable, non-invasive, eco-friendly and cost-efficient. This paper provides an overview of the various remediation and treatment technologies derived from risk-based approaches that are used for isolation, containment, separation, restoration reclamation and remediation of soil, sediments, surface water and groundwater contaminated by petroleum hydrocarbons and organic compounds.

Remediation of soil and water contaminated with petroleum hydrocarbon: A review

A comprehensive guide of remediation technologies for oil contaminated soil — Present works and future directions

Organic contamination and remediation in the agricultural soils of China : a critical review

Widespread pollution of terrestrial ecosystems with petroleum hydrocarbons (PHCs) has generated a need for remediation and, given that many PHCs are biodegradable, bio- and phyto-remediation are often viable approaches for active and passive remediation. This review focuses on phytoremediation with particular interest on the interactions between and use of plant-associated bacteria to restore PHC polluted sites. Plant-associated bacteria include endophytic, phyllospheric, and rhizospheric bacteria, and cooperation between these bacteria and their host plants allows for greater plant survivability and treatment outcomes in contaminated sites. Bacterially driven PHC bioremediation is attributed to the presence of diverse suites of metabolic genes for aliphatic and aromatic hydrocarbons, along with a broader suite of physiological properties including biosurfactant production, biofilm formation, chemotaxis to hydrocarbons, and flexibility in cell-surface hydrophobicity. In soils impacted by PHC contamination, microbial bioremediation generally relies on the addition of high-energy electron acceptors (e.g., oxygen) and fertilization to supply limiting nutrients (e.g., nitrogen, phosphorous, potassium) in the face of excess PHC carbon. As an alternative, the addition of plants can greatly improve bioremediation rates and outcomes as plants provide microbial habitats, improve soil porosity (thereby increasing mass transfer of substrates and electron acceptors), and exchange limiting nutrients with their microbial counterparts. In return, plant-associated microorganisms improve plant growth by reducing soil toxicity through contaminant removal, producing plant growth promoting metabolites, liberating sequestered plant nutrients from soil, fixing nitrogen, and more generally establishing the foundations of soil nutrient cycling. In a practical and applied sense, the collective action of plants and their associated microorganisms is advantageous for remediation of PHC contaminated soil in terms of overall cost and success rates for in situ implementation in a diversity of environments. Mechanistically, there remain biological unknowns that present challenges for applying bio- and phyto-remediation technologies without having a deep prior understanding of individual target sites. In this review, evidence from traditional and modern omics technologies is discussed to provide a framework for plant-microbe interactions during PHC remediation. The potential for integrating multiple molecular and computational techniques to evaluate linkages between microbial communities, plant communities and ecosystem processes is explored with an eye on improving phytoremediation of PHC contaminated sites.

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The Interaction between Plants and Bacteria in the Remediation of Petroleum Hydrocarbons: An Environmental Perspective

A review on the application of chemical surfactant and surfactant foam for remediation of petroleum oil contaminated soil.

Micro-macrobubbles interactions and its application in flotation technology for the recovery of high density oil from contaminated sands

Interaction studies between high-density oil and sand particles in oil flotation technology

The interaction studies between high-density oil and bubbles were investigated to understand the bubble attachment behaviour on oil with respect to bubble size, pH and temperature. An increase in the bubble size from 350 µm (microbubbles) to 1000 µm (macrobubbles) demonstrated a decrease in the attachment force due to the reduction in contact angle by 7%. The results were in good agreement with the bubble-strength visualization tests, as the retraction of microbubble attached onto oil demonstrated a significant change in shape from concave to convex, as opposed to constant shape of macrobubble attachment-retraction from the oil layer. This was attributed to a higher cross sectional area to volume ratio (IA:V) of 12.3 for oil-microbubble attachment compared to IA:V of 4.9 for oil-macrobubble attachment. Due to the higher IA:V, microbubble is more firmly attached onto the oil layer compared to macrobubbles. Therefore, microbubbles could help to enhance the flotation process as it would preferentially attach to the oil contaminant as opposed to macrobubbles. The results also indicate that increase in pH is detrimental for oil-bubble attachment due to the production of natural surfactants, while the increase in temperature does not appear to affect the bubble attachment on the oil layer.

Mee Wei Lim

Papers

A comprehensive guide of remediation technologies for oil contaminated soil — Present works and future directions

Micro-macrobubbles interactions and its application in flotation technology for the recovery of high density oil from contaminated sands

Interaction studies between high-density oil and sand particles in oil flotation technology

Analysis of attachment process of bubbles to high-density oil: Influence of bubble size and water chemistry