BOREHOLE WATER QUALITY TESTING AND TREATMENT

Borehole water can provide an important source of water for homes, farms, institutions, and commercial properties. However, clear water is not necessarily safe to drink. Dissolved minerals, microbial contamination, suspended particles, and naturally occurring chemical substances may affect water quality even when there is no visible sign of a problem.

Pro-Logic Technologies Limited provides technical support for borehole water system assessment, water quality testing coordination, treatment system planning, filtration assessment, and maintenance of associated pumping and water storage equipment.

The appropriate treatment depends on the water's intended use and the results of a suitable laboratory analysis. Testing should come before selecting a filtration or treatment system.

1. Why Is Borehole Water Quality Testing Important?

Groundwater quality varies with geology, groundwater conditions, nearby land use, borehole construction, and the condition of the storage and distribution system.

Water quality testing helps identify substances or organisms that may require treatment. It can also establish a baseline for future monitoring and help determine whether an existing treatment system is working effectively.

Testing is particularly important when:

• A new borehole has been drilled.
• Water is intended for drinking or food preparation.
• The water has developed an unusual smell, colour, or taste.
• There has been flooding or suspected contamination.
• Nearby sanitation systems or agricultural activities may affect groundwater.
• Scale, sediment, or staining is appearing in plumbing.
• A treatment system has been installed or serviced.
• Water quality has changed following borehole repairs or construction work.

Do not assume that boiling, filtering, or chlorinating water will remove every possible contaminant. Different problems require different treatment methods.

2. Common Borehole Water Quality Problems

Suspended particles and turbidity

Turbid water contains suspended material that can make it appear cloudy. Possible causes include fine sediment, disturbed borehole material, inadequate development after drilling, or problems within the water distribution system.

The cause should be investigated before choosing filtration equipment. Persistent sediment may require assessment of the borehole, pump installation, and pumping conditions.

High iron and manganese

Iron and manganese can cause reddish-brown or dark staining, discolouration, deposits, and unpleasant tastes. Their concentrations should be measured before selecting an appropriate treatment method.

Depending on the water chemistry, treatment may involve oxidation, filtration, or specialised media.

Hard water

Hardness is commonly associated with dissolved calcium and magnesium. It can cause scale on heating elements, water heaters, pipes, and fittings.

A water softener may be appropriate where hardness is confirmed and reduction is necessary. The system should be sized according to water demand, hardness levels, and the manufacturer's operating requirements.

Unpleasant smell or taste

Odour and taste problems can have several causes, including dissolved gases, organic substances, microbial activity, or chemical contamination.

The cause should be identified through appropriate testing rather than attempting treatment based only on smell.

Microbial contamination

Bacteria and other microorganisms may enter a water supply through contamination pathways associated with the borehole, its surroundings, storage tanks, or distribution system.

Water intended for drinking should be tested using an appropriate laboratory method. Disinfection may be necessary, but the treatment process should be selected according to the contamination risk and applicable drinking-water requirements.

Excessive salinity

High dissolved salts can make water taste unpleasant and may affect its suitability for drinking, irrigation, or industrial applications.

Testing can include electrical conductivity and total dissolved solids, followed by more detailed analysis where necessary. Reverse osmosis may be appropriate for certain salinity problems, but its suitability depends on the water chemistry and intended use.

3. What Parameters Should Be Tested?

The test panel should be selected according to the intended use, local requirements, and potential contamination sources.

For drinking-water assessment, relevant parameters may include:

• Microbiological: E. coli and other indicators specified by the laboratory or applicable standards.
• Physical: Colour, turbidity, temperature, and odour.
• General chemistry: pH, electrical conductivity, total dissolved solids, and hardness.
• Minerals: Iron, manganese, calcium, magnesium, and other relevant constituents.
• Chemical contaminants: Nitrate, fluoride, arsenic, or other substances where local geology and contamination risks make them relevant.

No single measurement proves that water is safe to drink. For example, a low total dissolved solids reading does not rule out microbial contamination, and clear water may still contain substances that require treatment.

Use a laboratory that can perform the relevant analyses and provide results suitable for comparison with applicable drinking-water standards.

4. How Borehole Water Samples Should Be Collected

Correct sample collection is essential because poor handling can affect the results.

Follow the receiving laboratory's instructions for the required containers, sampling point, flushing procedure, preservation, transport, and delivery time. Microbiological samples may require sterile containers and special handling.

Where practical, distinguish between the quality of the raw borehole water and the quality of water delivered after treatment. Separate samples may be needed to assess the borehole source, storage tank, and treated supply.

Record the sampling location, date, operating conditions, and whether the sample was collected before or after treatment.

Do not use an ordinary household bottle for a microbiological sample unless the laboratory specifically approves it. Incorrect containers and delays can compromise the test.

5. Borehole Water Filtration Systems

Filtration removes certain particles or contaminants from water. The correct filter depends on the size and type of material being targeted.

Sediment filters

Sediment filters can remove suspended particles such as sand and other material within the filter's rated range. They may help protect downstream equipment from particles, but they do not automatically remove dissolved chemicals or microorganisms.

Multimedia filtration

Some treatment systems use layers of filter media to remove suspended material and improve clarity. Design depends on the raw water quality, required flow, filter loading, and backwashing arrangements.

Iron and manganese filtration

Where testing confirms elevated iron or manganese, treatment may use oxidation followed by filtration or a suitable specialised medium. Performance depends on pH, dissolved oxygen, chemical conditions, and the selected media.

Activated carbon filtration

Activated carbon can reduce certain substances affecting taste and odour, including some organic compounds. It is not a universal treatment for every chemical contaminant and does not provide reliable disinfection by itself.

Cartridge filtration

Cartridge filters are used for specific particle-removal applications. Filter selection should consider the rated particle size, required flow, pressure drop, and replacement schedule.

Filtration equipment should be chosen only after the water quality and treatment objectives have been established.

6. Borehole Water Disinfection

Disinfection is used to control harmful microorganisms. Common approaches include appropriately designed chlorination and ultraviolet treatment.

Chlorination

Chlorination can disinfect water when the dose, contact time, water chemistry, and system conditions are suitable. Where required, residual disinfectant monitoring helps verify continued protection through storage and distribution.

The dosing arrangement should follow recognised guidance and applicable requirements. Do not estimate chemical doses without knowing the water conditions and treatment specifications.

Ultraviolet treatment

Ultraviolet systems can inactivate susceptible microorganisms when the equipment is correctly sized and operated. The water must meet the unit's requirements for clarity and UV transmittance.

UV treatment does not generally leave a disinfectant residual in the distribution system. Additional controls may therefore be necessary where recontamination is possible.

Neither method removes all dissolved chemical contaminants. Disinfection and chemical treatment serve different purposes.

7. Reverse Osmosis for Selected Water Quality Problems

Reverse osmosis uses a membrane to reduce many dissolved substances. It may be considered for certain salinity, dissolved-mineral, or specific contaminant problems when supported by water analysis.

The design must account for feed-water chemistry, pressure, flow demand, membrane selection, pretreatment, and concentrate disposal.

Reverse osmosis systems produce a treated stream and a reject stream. The reject water must be managed appropriately, and the system's recovery rate should be suitable for the available supply.

Pretreatment may be required to control sediment, scaling, iron, or other substances that could damage or foul the membrane.

Reverse osmosis is not automatically the best option for every borehole. A simpler treatment method may be more appropriate for a specific, confirmed problem.

8. Water Quality and Borehole Pump Performance

Water quality can influence pump reliability. Sand and abrasive particles may contribute to wear, while certain water chemistries can promote corrosion or deposits on system components.

If sediment levels increase, assess the borehole, pump setting, pumping water level, and operating conditions. Installing a filter at the property may not solve a problem originating within the borehole itself.

Pump selection and operating flow should remain compatible with the borehole's sustainable yield. Excessive pumping can cause the water level to fall and may contribute to sediment problems in some installations.

Maintenance should consider the pump, rising main, valves, storage tank, and treatment equipment as parts of the same water supply system.

9. Water Storage Tank Hygiene

Even when raw borehole water has acceptable quality, an inadequately maintained tank can introduce contamination.

Storage tanks should have suitable covers, protected openings, secure access points, and appropriately arranged inlet and outlet connections. The overflow and drain should be positioned to minimise the risk of contamination entering the tank.

Inspection and cleaning should follow a suitable schedule based on tank conditions, water quality, and the manufacturer's recommendations. Where microbial contamination is suspected, investigate the tank and distribution network as well as the borehole.

After cleaning, disinfection, or significant repairs, consider whether follow-up sampling is necessary to verify the condition of the supply.

10. Selecting the Right Water Treatment System

A reliable treatment design follows a sequence of assessment, analysis, selection, installation, and verification.

First, establish the intended use: drinking, cooking, bathing, irrigation, livestock, or a specific industrial process. Next, identify the water quality problem through appropriate testing.

Then select treatment equipment capable of addressing the measured contaminants at the required flow rate. Consider pressure loss, operating costs, filter replacement, chemical requirements, backwashing, electricity, wastewater, and access for maintenance.

After installation, verify performance using appropriate operating checks and, where necessary, follow-up laboratory testing.

A treatment system should not be described as producing safe drinking water solely because it has been installed. Its performance must be confirmed against the relevant requirements.

11. Borehole Water Quality Monitoring

Water quality can change over time. Periodic monitoring helps identify changes in the source, treatment process, storage tank, or distribution network.

The monitoring schedule should be based on intended use, applicable standards, local risks, previous test results, and advice from the relevant laboratory or water-quality professional.

Additional testing may be warranted after flooding, suspected contamination, major borehole repairs, treatment-system failure, or a sudden change in colour, taste, smell, or clarity.

Keep a record of laboratory reports, treatment changes, maintenance, filter replacement, disinfection, and any unusual events. These records make it easier to identify trends and plan corrective action.

12. Water Quality Assessment for Different Applications

Residential properties: Assess water intended for drinking, cooking, bathing, laundry, and household appliances.

Apartment buildings: Consider source quality, storage-tank hygiene, distribution conditions, and the needs of multiple occupants.

Schools and institutions: Prioritise drinking-water safety, tank hygiene, treatment maintenance, and appropriate monitoring.

Farms: Select tests according to whether water is used for irrigation, livestock, domestic purposes, or agricultural processing.

Commercial and industrial facilities: Identify process-specific requirements and contaminants that may affect equipment or production.

Water that is suitable for one application may not be suitable for another. Drinking-water quality requirements differ from irrigation and specialised industrial requirements.

Frequently Asked Questions

Is clear borehole water safe to drink?

Not necessarily. Some contaminants cannot be detected by sight, smell, or taste. Appropriate laboratory testing is needed to assess whether the water meets the relevant drinking-water requirements.

Can boiling make all borehole water safe?

No. Boiling can inactivate many disease-causing microorganisms when done correctly, but it does not remove most dissolved chemical contaminants and may concentrate some substances as water evaporates.

Does a sediment filter make borehole water drinkable?

Not by itself. Sediment filters remove particles within their rated range but do not necessarily remove bacteria, viruses, or dissolved chemical contaminants.

How do I choose a water treatment system?

Start with laboratory test results, intended use, required flow rate, and the contaminants that need to be reduced. Select equipment designed for those specific conditions.

Why does borehole water leave brown stains?

Iron is one possible cause, although other minerals or sediment may contribute. Test the water before selecting an iron-removal or filtration system.

Should water be tested after installing treatment equipment?

Yes, where appropriate. Follow-up testing helps establish whether the treatment is meeting its objectives and whether the delivered water meets the applicable requirements.

Contact Pro-Logic Technologies Limited

For borehole water system assessment, treatment planning, filtration equipment assessment, water storage inspection, and pump-system maintenance support, contact Pro-Logic Technologies Limited.

Phone: 0723763173
Website: https://prologictecnologies.co.ke

When requesting an assessment, provide the intended use of the water, any laboratory results, the symptoms observed, and details of existing filtration or disinfection equipment.

Test first, choose treatment based on the results, and verify the final water quality.