The Horizontal Directional Drilled Well (HDDW) technique is an unique and proven method for groundwater extraction and infiltration. This new technology has many different applications, and has advantages compared to other (similar) techniques. In this in-depth article you will learn what the basics are of the HDDW technology. Moreover, this text is a transcription of our video which explains the principles even better. For those who prefer to read, continue reading. We recommend our video though.
Video about our HDDW technique:
Basics of the HDDW method
‘HDDW’ stands for ‘Horizontal Directional Drilled Wells’. A filter tube is inserted into an aquifer by means of a horizontal directional drill. Together with a necessary pump, this creates a filter system that offers huge advantages compared to conventional methods. It is extremely important the dimensions of the filter holes correspond correctly to the soil composition to, ensure maximum filter functionality. The soil directly beneath the filter tube is the area filter.
Solution for consistent soil
It’s possible to determine the correct perforation of the filter tube beforehand, if the soil composition is consistent. Consequently, there will be no sand delivery and the system can continue to function optimally. However, if the composition of the soil is non consistent, then it’s impossible to determine the correct dimensions of the filter holes. The HDDW solves this problem. An artificial area filter is used, to create an optimal soil structure. Again, this makes it possible to calculate the perforation. This prevents the delivery of sand and results in an optimally functioning filter system. The installation of an HDDW starts with pilot drilling. Based on precise calculations, a borehole is drilled into the desired soil layer. Drilling fluid is added during the pilot drilling typically a mix with clay, which prevents the borehole from collapsing in on itself, while removing the drilled soil. After the pilot drilling, a so called ‘reamer’ is used, to empty the borehole until the desired diameter is achieved. The filter system is then installed. The first step involves installing a pipe sleeve. The natural area filter is used if the soil composition is consistent. A filter tube is drawn through the pipe sleeve. The pipe sleeve is removed as soon as the filter tube is positioned correctly. The drilling fluid is transported away from the drilled location at the same time. The soil collapses around the filter tube, and the water present redistributes itself along the soil and the filter.
Solution for non-consistent soil
However, if the soil composition is not consistent, then it’s necessary to opt for an artificial area filter. There are two ways to achieve this. The first method involves enwrapping the filter tube with an artificial area filter beforehand. The soil then sinks onto the area filter and the pipe sleeve is removed. The second variation involves fitting an interior support pipe in the pipe sleeve. This extra pipe installs the artificial area filter when the pipe sleeve is removed. The soil once again subsides and the filter system is installed. In order that the filter system functions as required, the area filter is permanently integrated into the soil after the installation. We call this: ‘generating the soils’. The removal of the drilling fluid when pulling the pipe sleeve away, is an important first step. The area filter is then optimized. By means of extracting water with a high with a high flow rate, all by means of mechanical vibrations, the fine particles and the last pieces of the drilling fluid are loosened and drained away through the filter tube. This ultimately results in a clean area filter, with a natural transition into the existing soil and material. The HDDW is now ready for use.
- Extraction of drinking water
- Underground heat and cold storage
- Redevelopment/ decontamination
- Stabilisation of land and dikes
- Rain-water infiltration, and
- Groundwater management
- Is installed in one single, possibly thin, aquifer
- Offers a huge capacity per filter
- Is low maintenance
- Involves fewer pumps and pipes
- Requires less space
In short (summary)
The HDDW offers you a sustainable, qualitative solution for water extraction or infiltration against a minimal Total Cost of Ownership. Would you like to know more about the specific advantages applicable for your use? Please feel free to contact us via our contact page.
- Harry Bos, Resultaten DMC-systeem in AIO experiment 2012, October 5th 2012 (PDF)
- Jan Willem Kooiman, Oman-Netherlands, Masqat, October 16th 2010 (PDF)
- Dutch Water Sector on the HDDW technology, April 1st 2007 (Article)
- More educational video’s on our YouTube channel.