Bioremediation of contaminated soil and groundwater by in situ biostimulation

Abstract

Bioremediation by in situ biostimulation is an attractive alternative to excavation of contaminated soil. Many in situ remediation methods have been tested with some success; however, due to highly variable results in realistic field conditions, they have not been implemented as widely as they might deserve. To ensure success, methods should be validated under site-analogous conditions before full scale use, which requires expertise and local knowledge by the implementers. The focus here is on indigenous microbial degraders and evaluation of their performance. Identifying and removing biodegradation bottlenecks for degradation of organic pollutants is essential. Limiting factors commonly include: lack of oxygen or alternative electron acceptors, low temperature, and lack of essential nutrients. Additional factors: the bioavailability of the contaminating compound, pH, distribution of the contaminant, and soil structure and moisture, and in some cases, lack of degradation potential which may be amended with bioaugmentation. Methods to remove these bottlenecks are discussed. Implementers should also be prepared to combine methods or use them in sequence. Chemical/physical means may be used to enhance biostimulation. The review also suggests tools for assessing sustainability, life cycle assessment, and risk assessment. To help entrepreneurs, decision makers, and methods developers in the future, we suggest founding a database for otherwise seldom reported unsuccessful interventions, as well as the potential for artificial intelligence (AI) to assist in site evaluation and decision-making.

The function of microbial enzymes in breaking down soil contaminated with pesticides: a review

“…Conventional methods of treating contaminated soil, such as soil washing, excavation, land filling, incineration, coagulation-flocculation, chemical oxidation, filtration, and photodegradation are generally time-consuming, expensive, and do not always provide a complete solution, resulting in secondary pollutants [ 65 , 66 ]. For example, high temperature incineration decomposition offers highly efficient pollutant removal, but it is neither economical nor socially acceptable [ 65 ].…”

“…It has technical and cost benefits, even though bioremediation might take more time to carry out than conventional methods [ 65 ]. Employing microbes for degradation and detoxification of contaminants is now being increasingly employed as the preference technology for site clean-up [ 33 , 66 ]. In contrast to the conventional approaches, bioremediation more sustainable with less harmful byproducts being produced [ 21 , 33 ].…”

Molecular Fingerprinting of the Biodegradation of Petroleum Organic Pollutants in Groundwater and under Site-Specific Environmental Impacts

“…Petroleum is a complex mixture that contains thousands of different organic compounds with various physical-chemicalbiological features [11][12][13], which differentiate their fate and migration pathways and make in situ remediation complicated [14,15]. Once hydrocarbon contaminants infiltrate into the subsurface and groundwater, they are subjected to various natural attenuation processes [16,17], which can be divided into abiotic processes and biodegradation [18,19]. Because of this environmentally friendly feature, biodegradation is considered a promising approach and has been widely used in groundwater petroleum remediation [20].…”