Waterra has been providing customers with Simple Solutions for Groundwater Monitoring since 1985. Our product line has grown considerably to include pumps, filters, water level and hydrocarbon detection equipment, water quality testing equipment, bailers and other accessories.Waterra products are designed with the goal of making your life easier in the field.
- Business Type:
- Industry Type:
- Soil and Groundwater - Soil and Groundwater Monitoring and Testing
- Market Focus:
- Globally (various continents)
- Year Founded:
The equipment that Waterra provides is suitable for a wide variety of applications that go well beyond purging and sampling monitoring wells. A range of these applications and special situations and the equipment suitable for use in them are listed below.
In some situations sampling pumps may not be suitable for purging or sampling some wells. These situations could arise as a result of budget limitations, site logistics or even monitoring well characteristics.
Monitoring wells should always be capped in order to prevent foreign material from contaminating the well. Often the simplest method used to cap monitoring wells is to place a blind end cap over the open end of the well. Blind end caps are inexpensive and simply press fit onto the well. These caps are available from PVC suppliers and are made for both schedule 40 and 80 pipe in a wide range of sizes. These caps however do not provide any security for the monitoring well.
Piezometers or wells that have lost their original diameter as a result of collapse or obstruction by other equipment can continue to be sampled with the Waterra Inertial Pump.
Waterra currently offers three devices that can be used to collect samples of groundwater: the Waterra Inertial Pump, Waterra Disposable Bailers and the Waterra 12 Volt Submersible Pump. These products offer different features that cover most sampling needs in a broad range of sampling environments.
In the last few years, the popularity of establishing piezometers using drive point technology has increased substantially. The concept is to drive a hard point into the ground to establish a shallow piezometer. In order to drive these piezometers into the ground, they must be narrow diameter (approximate inner diameter of 1/2 inch (1.25 cm).
Unfortunately there are many sites where the groundwater is contaminated with hydrocarbon products. Some of these products are lighter than water (floaters) and some of them are heavier than water (sinkers). Naturally the presence of these products is not a good thing and it is of keen interest to establish their presence and if so how much product is present.
Once the presence of hydrocarbons is established, the usual course is to implement a remediation program. Of course, there is a requirement to monitor the hydrocarbon contamination on an ongoing basis to see how the remediation is progressing.
So the question is 'How does one detect and discriminate between oil and water down inside a narrow diameter well?'
Many jurisdictions specify that groundwater samples that are collected for the purpose of determining metal content must be passed through a filter having a 0.45 micron pore size. The philosophy is to remove suspended particulate matter that may contain or carry metals. It is argued that the particulate matter is not likely part of the normal groundwater flow but rather a byproduct of establishing wells and sampling groundwater. The bottom line is, there is a requirement for an efficient, cost effective means of filtering groundwater samples. To the extent that this can be accomplished in the field as the sample is collected then so much the better.
Purging, in the groundwater context, is the removal of volumes of well water. One may want to purge to remove the stagnant standing water from the well and allow fresh formation water to fill the well prior to sampling. Numerous clients report that they purge the equivalent of three well volumes prior to sampling, but protocols vary.
The other major purging reason is to draw down the well and hence the water table so as to establish a hydraulic gradient towards the well. This is typical in a recovery type situation where contaminants are encouraged to flow towards the well. Here, the purging is typically done over longer periods of time. This purge and recover type of application is described under the section entitled Well Development.
Surging is the process of creating a larger than usual flow through a screened interval usually with the goal of cleaning out smaller particulate matter or biological matter from the filter pack and/or adjacent formation.
This accumulated particulate or bio matter can be a potential problems as follows:
- Sample quality can be affected by sorption of potential contaminants from the matter contained in the filter pack or the adjacent formation.
- Sample quality can be affected by chemical interaction between the well water and this material.
- Sample quality can be affected if material is drawn into the sample.
- This material may accumulate to such an extent as to inhibit flow from the formation into the well.
It is a frequent requirement of groundwater monitoring programs to sample for the presence of volatile organic compounds (VOC) in groundwater. This can be a complicated procedure because these compounds are by definition volatile, and through the sampling process these compounds may escape from the water. Depending on the volatility of the compound and the sampling technique, the concentrations in the sample may be severely reduced. This could lead to inappropriate conclusions and recommendations based on the poor quality samples.
The challenge is to inexpensively collect samples without losing the VOCs.
When groundwater investigators go to the field, one of the first things that they do is to remove the well cap from the well and then look down the well. Mostly what they see is black nothingness and even if they could see the water level, they still would not know the depth below grade of the water table.
Well development is an important part of monitoring well procedures and is usually required in order to acquire a quality sample and adequately determine formation parameters such as permeability.
Fines are frequently mobile and will move from a high concentration to a low concentration. The ultimate low concentration is of course your monitoring well. Fine material will accumulate in monitors and sand packs will silt up and may require redevelopment.
Detractors from the Waterra System have frequently stated that the Inertial Pump's action on the monitoring well increases turbidity.This is true in monitoring wells that require development. In a monitor that is properly developed, the inertial pump cannot increase turbidity as the colloidal material has been removed from the well and the sand pack as per the definition of development.
It is very common to come across wells that are filling up with sediment. The sediment may be derived from the sides of the well (especially if it is an open well), or it may be derived from a permeable formation that carries material into the well, or it may be surface derived material that ends up in the well in any number of ways. The bottom line, however, is that sediment accumulates in the bottom of the well and there are potential problems as follows:
- sample quality can be affected by sorption of potential contaminants into or from the well bottom sediment
- sample quality can be affected by chemical interaction between the well water and well bottom sediment
- sample quality can be affected if well bottom sediment is drawn into the sample
- well bottom sediment may accumulate to such an extent as to inhibit access to the screened interval of choice.