Electrokinetic Enhanced Bioremediation of Soils Contaminated with Petroleum Hydrocarbons

Desorption of phenanthrene resulting from hydraulic flow is compared to desorption driven by electroosmotic flow with a similar flow rate. The power required for the hydraulic flow test was compared with the consumed power in the electrokinetics test. A novel approach, anode-cathode-compartment (ACC), was proposed to stabilize pH and distribute nutrients in soil in order to enhance electrokinetic bioremediation of soil contaminated with biodegradable compounds. The ACC technique was applied to investigate electrokinetic bioremediation of soil contaminated with phenanthrene. Mycobacterium pallens sp. was used to degrade phenanthrene. Solar energy was used to generate power for the hybrid technique. Three distinct bacterial strains designated as AC16, SM155, and SB53, were subjected to investigation, including ability to grow in liquid medium at different diesel fuel concentrations, identifying functional genes, and the ability to grow at different temperatures and pH. Electrokinetic bioremediation with ACC technique was conducted to mitigate soil contaminated with diesel fuel. The tests were conducted using the novel bacterial strains AC16, SM155 and SB53. The results showed that, the phenanthrene concentration in effluent samples after desorption by electroosmotic flow was found to be three to four times the concentration after desorption by hydraulic flow. The new ACC technique overcomes the shortcomings of other pH stabilization techniques by stabilizing the pH without the need for pumping or amendments. The use of solar panels as a sole source of power can reduce electricity transmission expenses and eliminate power loss in transmission lines. Diesel degradation in tests conducted with electrokinetic bioremediation was between 20 and 30%

Integrated solar electrokinetic remediation of soil contaminated with copper

Electrokinetic remediation is an emerging in-situ technology for cleaning contaminated soil. The contaminants are mobilized by passing a low-level direct current between a row of positively charged electrodes (anode) and negatively charged electrodes (cathode). Due to the low electric current required by the technology, solar power can be an excellent option for providing the electric field. Along with the environmental benefits of solar power, solar cells can provide electricity in remote sites with no access to power lines. The electrolysis reactions in electrokinetic process generate an acid front at the anode and a base front near the cathode. The acid front travels by electroosmosis and electromigration towards the cathode, while the base front moves by electromigration to the anode. The base front reacts with the cations in the soil pore fluid causing premature precipitation of the cations as heavy metal hydroxides at a distance from the cathode equal 0.3 to 0.5 times the distance between the electrodes

Enhancement of Bioremediation and Phytoremediation Using Electrokinetics

This chapter discusses the use of bioremediation and phytoremediation coupled with electrokinetics and presents the elements contributing to the success of the remediation process. A deep discussion and an overview of the current advancement in the biotechnologies are outlined in details. Innovative solutions for challenges facing the field application of the new technology are presented and new directions are proposed. A careful review for contaminated site conditions including pH, temperature, and other factors influencing the behavior of microbial community are presented. Great deal of discussion is around overcoming the adverse effect of electrolysis reactions, which is a by-product of electrokinetics. The discussion includes prolonging the survival of the indigenous bacteria, increase of microbial enzyme secretion, improvement of the indigenous bacteria metabolism, and exploration of metagenomics resources from soil biota. The challenges facing the field application of bioremediation and phytoremediation including the delivery of the electron donors and/or acceptors and nutrients to microorganisms involved in the biodegradation, particularly in clay soils, which has very low hydraulic conductivity, is discussed. The use of electrokinetics in biostimulation application to enhanced degradation of organic pollutant is reviewed. The implementation of bioaugmentation in bioremediation coupled with electrokinetics to enhance the outcome of bioremediation is presented

Wastewater Treatment Using Constructed Wetland: Current Trends and Future Potential

Constructed wetlands (CW) is an environmentally friendly technique for removing pollutants from wastewater and has been applied to municipal wastewater, petroleum refinery wastewater, agriculture drainage, acid mine drainage, etc. The past decade has seen a remarkable number of innovations in the exponentially growing field of microbiology. This manuscript covers a critical review of key aspects of CW, such as various types of CW, the contaminants and their removal mechanisms, degradation pathways, challenges and opportunities, materials, applications, and theory with a focus on recent advances in the last three decades. In addition, an attempt has been taken to project future advances in the field of CW and facilitate these advances by framing key unsolved problems in CW. Guidelines are prepared for the fast-growing CW field through the standardization of key design aspects. This review covers the evaluation of the current state-of-the-art of CW technology and provides definitions and performance metric nomenclature in an effort to unify the fast-growing CW community. It also contains an outlook on the emerging trends in CW and proposes future research and development directions