Water Level Loggers

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Low Flow Groundwater Sampling

Dedicated Bladder Pump

Our dedicated bladder pump is small, efficient and can be left in situ. These pumps are ideal for low flow groundwater sampling from depths of up to 60 metres because, when dedicated to a well, samples are not disturbed, the pump is left in situ so sampling is always done from the same location for high quality, repeatable results. This method can save set-up time, time to de-contaminate the equipment and produces better, more accurate results.

Peristaltic Pump (Advanced)

Advantages

The Peristaltic Pump - Advanced is an electronic peristaltic pump with advanced memory option. This reliable and universal electronic peristaltic pump can create a perfect vacuum; it is a versatile pump for sampling and purging in shallow wells. Peristaltic Pumps are used for low flow sampling of groundwater; this pump is perfect for the attachment of an in-line filter, for use with a flow-through cell and multi parameter probes. Available with optional auto shut off to assist compliance with the latest standards and directives when low flow sampling in monitoring wells.

Benefits:

  • Reliable and easy to use and maintain
  • Splash proof for use in the field (IP64)
  • Built in maintenance free battery that runs between 2 and 5 hours depending on conditions & charging
  • Can pump product and water even if it contains sediment
  • Optional auto shut-off for draw-down control
  • Cheap disposable tubing - no chance of cross contamination.

Specifications: Peristaltic Pump Advanced

Technical specifications
Weight: 13kgs and is easy to transport
Power supply: Internal battery
Battery: 2 - 5 Hours depending on conditions and charging
Head lift of water: 9.5m
Voltage: 12 volt
Product material: Stainless steel, teflon
Flow rate: 2.2 Litres per minute

Videos, Manuals & Downloads

Low flow sampling with a Peristaltic Pump Video

Basic Operations Video

Contact

Please email sales@vanwalt.com or click here to complete our enquiry form.

HDPE Tubing

Both our Silicone peristaltic pump tubing and Polyethylene tubing are available in many diameters and lengths to fit all types of pump. It is hallmarked and carries our QA plus stamp.

Water Level Meter

Water Level or Dip Meters are used to measure water depth. They are available from stock in various lengths from 10 metres to 100 metres and longer lengths to order. Graduations are in cm increments and trigger a light and sound signal when immersed in water. Bottom sensors are also available to sound the depth of the well.

YSI Pro Plus Photo Gallery

YSI Pro Plus

The YSI Professional Plus handheld multiparameter water quality testing meter provides extreme flexibility for the measurement of a variety of combinations.

The new Quatro cable attached to the Pro Plus allows you to utilise 4-ports to measure temperature/conductivity, DO, and any two ISEs among pH, ORP, ammonium, chloride, or nitrate.

The Pro Plus instrument meets the demands of true field work. The instrument is rated to IP-67 standards even without the battery cover on. Other tough features include a -year warranty, Mil-spec connectors, rubber over moulded case, and a 2-year cable warranty. In-house testing procedures also include 1-meter drop tests from all angles to ensure expected field-durability.

Flowcell

Flow-through Cells are available for the YSI multi-parameter probe or with cut-outs for generic industry standard electrodes. They are normally used with peristaltic pumps.

Environmentally friendly low flow monitoring sampling solutions

Better, cheaper, more accurate and environmentally friendly monitoring solutions

We have bladder or peristaltic pumps and water quality meters to measure stability of parameters such as pH, DO and turbidity – full micro purging solutions available to buy or rent.

No purge sampling devices can save time and money so it's easy to see why they are gaining acceptance. In addition to the cost savings the logistics of no purge samplers are simple and above all it's 'green' technology. Like most new techniques it would appear that there is no "one size fits all" solution as some no purge samplers are good for VOC's and others for inorganics.

The Snap Sampler, now used extensively by companies like Shell, DuPont, Eastman-Kodak and Chevron who have 400 in boreholes in Australia, takes an instant 'snap' sample at a point in time. This sample can be depth specific and importantly is never exposed to the atmosphere. Alternatively Sorbisense collects a time interval profile, absorbing the sample over a period of time.

High Volume Purging

Prior to March 2011, high volume purging and sampling was mandatory for groundwater investigations on behalf of environmental research. After a well is constructed, well development should occur as soon as possible but not sooner than 48 hours after the swelling of the bentonite is completed. Thereafter groundwater sampling may take place after a 14 day wait. The well must then be purged at 3 times the wet well volume which includes the filter sand pack, prior to each sampling. During this process field parameters should be measured. Clearly, high volume purging produces much waste water which must be disposed of correctly and this can be expensive. Additionally, this technique may be risky for low recharge wells as it may draw the water level below the filter section of the well and introduce air to the sample.

Low Volume Purging

Low flow or micro purging is now an accepted method in the United States (Puls and Barcelona 1996) and in the UK following the publication of BS 10175:2011 in March 2011. With this type of sampling, a pump is hung in the well opposite the most contaminated zone in the well screen and adjusted to a very low speed. There is no need to renew (purge) the water in the blind section of the well. By using this method, the volume of the purge water can be reduced, sometimes significantly over the conventional purging method. Water quality indicator parameters are measured (pH, EC, DO and increasingly turbidity: EC and DO are the best stability indicators) until stability is achieved. After 3 successive readings of the water quality indicator parameters have stabilized (recorded after a minimum of one tubing, pump and flow-cell volume) per cycle then sampling can begin. It is customary, but not written in stone that drawdown is kept within 10 and 20cm and this should be regularly checked with a dipmeter. This technique is excellent for slow recovering wells and saves much time and purge water disposal volumes. A dedicated pumping system for each well is recommended. This ensures minimal mixing of the stagnant water above the screen.

Passive or Diffusion Sampling

"No purge devices are now beyond the infancy stage in the United States and have been gaining more acceptance since their first introduction in 2006. No doubt the technique will gain popularity in the EU. The idea is to deploy a device and leave it in a well for a certain period which may vary depending on the instrument used. Diffusion samplers need to reach an osmotic equilibrium with the surrounding water. Diffusion samplers are not a "one size fits all" solution and some are good for VOC's and SVOC's, such as the GORE samplers whereas others might be good for inorganics such as Columbia's RPP samplers. The common factor is that there is minimal disturbance in the water and whereas samplers such as the Hydrasleeve are an attractive low cost solution care must be taken that they do not disturb the sediment within the well which can cause excessive turbidity and perhaps cannot be implemented for sensitive analytes such as Redox, pH and Turbidity. Other systems are coming on the market and some offer a completely different solution for a buffet of compounds. Of great interest is the Snap Sampler from Prohydro which does not work on the principle of diffusion but rather grabs or "snaps" a sample of groundwater. Of all the samplers available at the moment this has the best proven track record of repeatability. Unlike the Hydrasleeve, it does not disturb the well water and therefore is perfectly suitable for all analytes. Where a conservation liquid needs to be used (such as metals) then that facility is catered for.

Passive, diffusion or no purge sampling has three huge benefits: They save time and money (50-80%), the logistics are simple and above all it is "green" technology.

Low Flow or No Flow Sampling Solutions