ASSIGNMENT
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Ref No: 3246
- Pump and treat combined with hydraulic gradient control for groundwater remediation and receptor protection.
In the view of Rivett et al. (2006), in the past few years, there has been an increase in number incidence of the groundwater pollution that has led to an increasing interest in the best possible ways for the management as well as the restoration of the contaminated sites.
Along with this interest is being developed in the improvement ofthe management tools for the aquifers that can integrate with the flow of ground water and also the transport simulation of the solute by using the optimization methods.
Like it was seen during experiments that adaptation of such methods can help the hydrologists in the evaluation as well as the planning schemes that are designed forthe restorationof the aquifers. Particularly scientists put forward a design for the methodology of control through hydraulic gradient that aimed of containing and also the removal of the contaminants from the groundwater.
After the contaminated groundwater is being excavated from subsurface by the use of pumps, it is treated before its discharge. Thus this methodology is called as the pump-and-treat system. This is most abundantly used method for remediation of the groundwater. It is also mostly associated with the treatment strategies like Air Stripping, Liquid-phase Granular Activated Charcoal and etc. (Rivett et al., 2006).
The design of the wells and the pumping system and the method of treatment aremostly dependent on characteristics of the contamination site and the type of targeted contaminant. It is common to find wellswhere groundwater is being extracted ata same time.
Such wells are screened at varied depths in order to maximize their efficiency. One of the very major components of any such groundwater pumping system comprises a monitoring program for the ground water that verifies the efficiency of the system.
It Monitors the cleanup and also allows the operator to adjust the system as a response to the changes in the conditions of the subsurface (Matott, Rabideau and Craig, 2006).
One main issue faced by a pump-and-treat plant during work is the determination of time when to turn off the system. For the contaminants levels that have been regulated by EPA, the levels that established under “Safe Drinking Water Act” are mostly the prevailing levels which are met by the ground water.
The requirements for the termination are basically based on objectives for the cleanup which have been defined during the preliminary stages of the process of remedial that are combined with the aspects (site-specific) that were revealed during the remedial operations (Chang, Chu and Hsiao, 2007).
Assignment. Many limitations and concerns are associated with the pump and treat systems. First of all they are very time taking approximately about 50-100 years I order to reach their cleanup goals. The pumping of the contaminated water from the surface depresses levels of the groundwater which leave residuals onto the soil.
After the levels of the groundwater return to their actual normal level the contaminants that had been absorbed on soil surface become dissolved. This dissolving of the absorbed contaminants on the surface of the soil is called as “rebound.”
The tests for there bound should be regularly and frequently performed during the early years after turning off the pump and treat system from any site or may be also after any major rain or any flooding event in a particular area.
The decontamination of ground water through hydraulic control is designed to lower the potentionchiometeric surface or the water table in order to reduce the discharge of the off-site.
It is done to minimize the rate of migrations by the removal of the contaminated waste materials and also to limit plume to a low water table which is formed due to the combination of injection and pumping wells.
Assignment A proper sentience of the pumps and the wells has to be insured in this method and the system responds according to the changes seen in the ground water levels.
Moreover, the physical and biological units for the treatment above ground may be important to tackle any kind of contaminated water that is to be pumped by wells (Bayer, Finkel and Teutsch, 2005).
In the last few decades specifically, after the 1990’s thorough studies of the pump and treat systems were carried out which indicated that the standards for the drinking water are somehow impossible to achieve in a small time frame on many sites.
During the years 1982 to 1992 73 percent of the cleanups of the super fund sites of the groundwater that has been contaminated were recorded using this pump and treat system technology. The practicality and affectivity of this procedure largely depend on the hydrogeological and properties of the contaminant under treatment.
In case of increasingly difficult sites fortreatment, the possibility of a total cleanup is reduced to a great extent and chances of success are least (Chang, Chu and Hsiao, 2007) Assignment
According to Bayer, Finkel and Teutsch(2005), there are many different alternatives that are adopted for the removal of the contaminants by the hydraulic control at the subsurface level which may be a part of an overall plan for remediation of a site.
Amongthem, the mostly used methods are the pump wells. Basically the pump wells are used to excavate the groundwater that has been contaminated from a saturated sire by the creation of a capturing zone for the migrating contaminants Assignment.
The most problematic thing that is being faced is the complete treatment and disposing of the water that has been contaminated. For this purpose, on-site facilities for their treatment are necessary before the reinjection of the water back into the contaminated water or maybe the release to the sanitary system surface.
Assignment. The pumping out of the contaminated water from the ground is carried out by the use of standard good mechanics and hydraulic gradient principles and also the capture zone phenomenon.
If the concepts of hydrogeology are conducive during the injection and pumping systems then many different design approaches can be adopted in order to develop a reliable and efficient system for the removal of the contaminants.
The most practical design that has been adopted successfully was for sandy or silty soils or sands which have been clearly characterized and they include those where the goals for the cleanup were not very strict (Matott, Rabideau and Craig, 2006).
2) Continuous ground gas monitoring as a means of speeding up ground gas risk assessments.
According to Park et al. (2008), there are many gasses present in the ground which include carbon dioxide and methane that are found in the soils as well as in rocks because they constitute an important component of the geochemical cycle of planet Earth. The risks which arise due to the presence of all these gasses is normally because of
- The accumulation of these gasses in large volumes
- The abrupt release of the gasses in a confined area
- Or maybe the combination of above-mentioned possibilities
This condition requires the presence of the fissures and cracks in the surface of Earth which can act in the form of conduits with high permeability in order to release the gasses from the ground. Assignment
Examples of such cracks and fissures are the faults in the surface of the earth and the volcanic activity like for example countries like Italy and Baku…………………….continued
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