23
Jul

WATER BOREHOLE REHABILITATION

WATER BOREHOLE REHABILITATION

Rehabilitation is the act of restoring something to its original state. What you need to know about borehole rehabilitation:

There are a number of potential causes for reduced yield from a domestic or commercial water borehole. These may include, but are not limited to:

  • Mechanical Blockage: mechanical blockage occurs when small soil particles or by-products from the well-wall build up and cause blockages or reduced flow.
  • Chemical Encrustation: essentially the chemical version of a mechanical blockage, chemical encrustation occurs when chemical deposits build up on the well screen or gravel pack and restrict the flow of water.
  • Bacteriological Plugging: Bacteria and other micro-organisms can also clog a borehole

How Borehole Rehabilitation Is Being Done

While the steps that need to be taken in order to rehabilitate a borehole will vary depending on the nature of the cause for the blockage or reduced flow, the following steps constitute a brief overview of the traditional steps borehole rehabilitation could or would necessitate:

1. A survey of the borehole will be undertaken first – the surveyor may ask you questions such as:

  • What was the initial depth of the borehole?
  • What the original yield was like compared to the current, reduced yield?
  • What is the diameter of the borehole?

The surveyor may also test the pH level of the water and perform other such assessments as indicated in order to diagnose the cause of reduced flow.

2. The pumping mechanism and/or other removable parts will be cleaned with a chlorine solution.

3. The borehole will be drained of all water and will be thoroughly cleaned of all sediment and debris.

4. Any damage to the inside of the borehole will be repaired. If the damage is too extensive, the borehole may be re-lined as opposed to simply repaired/patched.

5. The well itself will now be cleaned with chlorinated water.

6. Should the borehole/well require chemical cleaning it will take place at this juncture. If the well needs to be chemically cleaned, the process could take anywhere from 1 to 3 days and will mean the well needs to be dewatered thereafter in order to remove the chemicals and chemical residue.

7. The well/borehole will be disinfected. Chlorination is the most common method of disinfection undertaken.

8. Post chlorinated  well/borehole will need to be dewatered. The water will be tested until chlorine levels are back below 0.5mg per litre.

9. The well/borehole will be resealed.