Environmental remediation
[5] In the United States, the most comprehensive set of Preliminary Remediation Goals (PRGs) is from the Environmental Protection Agency (EPA) Regional Screening Levels (RSLs).
It wasn't until the use of newer polymer and chemical grouts in the 1950s and 1960s that Federal agencies of the US government recognized the need to establish a minimum project life of 50 years in real world applications.
[12] The Department of Energy is one US government agency that sponsors research to formulate, test and determine use applications for innovative polymer grouts used in waste containment barriers.
Portland cement was used in the past, however cracking and poor performance under wet-dry conditions at arid sites need improved materials to remedy.
Field implementation remains challenging: different environmental and site conditions require different materials and the placement technologies are specific to the characteristics of the compounds used which vary in viscosity, gel time and density:[13] "The selection of subsurface barriers for any given site which needs remediation, and the selection of a particular barrier technology must be done, however, by means of the Superfund Process, with special emphasis on the remedial investigation and feasibility study portions.
The chemical compatibility of the material with the wastes, leachates and geology with which it is likely to come in contact is of particular importance for barriers constructed from fluids which are supposed to set in-situ.
Recent advancements in bioaugmentation and biostimulation of the excavated material have also proven to be able to remediate semi-volatile organic compounds (SVOCs) onsite.
[citation needed] For most biodegradable materials like BTEX, MTBE and most hydrocarbons, bioreactors can be used to clean the contaminated water to non-detectable levels.
[citation needed] Depending on geology and soil type, pump and treat may be a good method to quickly reduce high concentrations of pollutants.
It is more difficult to reach sufficiently low concentrations to satisfy remediation standards, due to the equilibrium of absorption/desorption processes in the soil.
[citation needed] Solidification and stabilization work has a reasonably good track record but also a set of serious deficiencies related to durability of solutions and potential long-term effects.
[citation needed] Stabilization/solidification (S/S) is a remediation and treatment technology that relies on the reaction between a binder and soil to stop/prevent or reduce the mobility of contaminants.
[17] Oxygen gas or ambient air can also be injected to promote growth of aerobic bacteria which accelerate natural attenuation of organic contaminants.
[citation needed] The injection of gases into the groundwater may also cause contamination to spread faster than normal depending on the hydrogeology of the site.
SVE and MPE utilize different technologies to treat the off-gas volatile organic compounds (VOCs) generated after vacuum removal of air and vapors (and VOCs) from the subsurface and include granular activated carbon (most commonly used historically), thermal and/or catalytic oxidation and vapor condensation.
In soil or groundwater nanoremediation, nanoparticles are brought into contact with the contaminant through either in situ injection or a pump-and-treat process.
Most field applications of nanoremediation have used nano zero-valent iron (nZVI), which may be emulsified or mixed with another metal to enhance dispersion.
[21][22] That nanoparticles are highly reactive can mean that they rapidly clump together or react with soil particles or other material in the environment, limiting their dispersal to target contaminants.
One of their concerns is that the toxic chemicals would lead to the microbe's gene degradation, which would then be passed on to other harmful bacteria, creating more issues, if the pathogens evolve the ability to feed off of pollutants.
[25] It is dependent on saprophytic insect larvae, resistant to adverse environmental conditions and able to bioaccumulate toxic heavy metal contaminants.
[26][27] Black soldier fly larvae (BSFL) have also been used to monitor the degradation and reduction of anthropogenic oil contamination in the environment.
[citation needed] Cleaning of oil contaminated sediments with self collapsing air microbubbles have been recently explored as a chemical free technology.
The proponent needs to learn about "sensitive" (future) uses like childcare, schools, hospitals, and playgrounds as well as community concerns and interests information.
The use of incremental health risk is based on carcinogenic and other (e.g., mutagenic, teratogenic) effects and often involves value judgements about the acceptable projected rate of increase in cancer.
[citation needed] Monitoring for compliance against each standards is critical to ensure that exceedances are detected and reported both to authorities and the local community.
[citation needed] Enforcement is necessary to ensure that continued or significant breaches result in fines or even a jail sentence for the polluter.
[30] Dioxins from Union Carbide used in the production of now-banned pesticide 2,4,5-Trichlorophenoxyacetic acid and defoliant Agent Orange polluted Homebush Bay.
[citation needed] After three years of intensive research by the Croatian government, the EU funded the immobilization project in Bakar.
