INTRODUCTION
Water tests are important to detect types of contaminants in the water and water treatment is an important process to remove contaminants.
Regular testing of the water supply could be helpful to ensure a safe water supply. This data is valuable in solving possible future problems and alleviating the existing problem in the water treatment system.
Importance of water testing
Water testing could be used to identify the suitability of the water source. For example, drinking water, livestock water or irrigation water. Results of the water testing could be used as data to analyze the quality and the usage of water. Hence, there would be a more effective water resources distribution.
Water testing is also important to identify possible issues that exist on the water source. For instance, if water contains coliform bacteria. Water testing could detect the presence of harmful bacteria, which could possibly cause water borne diseases. Then, specific problems of the water sources could be addressed clearly and appropriately. Water testing is important to secure public health and ensure the reliability of water sources.
Water quality Testing- Types
- Basic water test (pH, ions: sodium, chloride, iron, lead, fluoride)
Water sources may be contaminated by waste from factories. Excessive amounts of ions may impact the smell, taste and the quality of the water. For instance, Fluoride is a micro-nutrient which is important to health. However, excessive amounts of fluoride would trigger dental problems.
- Coliform tests
Water sources may be contaminated by animal and human waste. Coliform bacteria would worsen the water quality and trigger water borne diseases. Coliform tests detect the presence of harmful microorganisms in water. For example, the amount of E. coli in water.
- Nitrate and phosphate tests
Fertilizers, pesticides and waste of the manufactory might leak into the water sources. High levels of nitrate in water would affect the quality of water and indicate the presence of other contaminants. For example, the oxygen level of the water.
- Mineral tests (lead, copper, heavy metal, sodium)
Mineral testing is important to determine the quality of the water sources and prevent the contamination of several types of minerals.
- pH tests
pH is the measurements of hydrogen ions in the water samples. Acidic and alkaline would affect the taste and the health of water.
- Chloride tests
High levels of chloride are usually present in contaminated water. The measurement of chloride is important to prevent the corrosion of pipelines.
- Turbidity tests
The testing of turbidity is the measurements of the amount of particulate matter in the water. High levels of turbidity of water would affect the cleanness of water.
- Salinity tests
Salinity tests is the testing of sodium chloride in the water samples
- Pesticide tests
- Electrical conductivity tests
Water quality Testing- Steps
- Identify testing options
Factors of testing options:
- Objectives (e.g., Identify an appropriate drinking water source)
- Test parameters
– Concentration range, accuracy and precision
- Time
- Need (e.g., Assessing the effectiveness of a water treatment technology, Donor request, Government verification of a treatment technology)
- Technical skills (Capacity of staff to conduct testing, Availability of staff and training levels, Availability of testing equipment and consumable items)
- Budget (e.g., Cost of equipment and consumable items needed for testing
and Staffing costs)
2. Collecting samples
Step 1: Collect water samples using a sample container (vial or cup) and fill the container to the marked level carefully.
Coliform tests: sterile containers should be used to collect samples.
All tests (samples from taps): let the water samples run for about 3-5 minutes before collecting for better results.
Step 2: Handle and preserve the collected samples carefully for better results.
Keep the samples in cool place (20 ºC – 32.2 ºC) and place the samples carefully
Water tests and recommended tests
3. Getting results
3.1 Using test strips
The changing colour of the test strips determine the concentration of certain types of chemicals in the water samples.
Step 3: Immerse the test strip in the desired water sample and remove within 5 seconds
Step 4: Hold the strip horizontally and gently tap or shake to remove excess water. Take extra precaution to ensure that the water from test pads don’t bleed into each other
Step 5: Read the test results carefully within 60 seconds in a good light and with the test area held near the colour chart on the bottle label. Changes in a colour that appear along the edges of the test pads or after more than 2 minutes have passed are no significance.
3.2 Using colour disk kits
Compared to test strips, colour test kits are available for a wider range of chemical range.
Step 3: Adds a powder packet or a few drops of a liquid reagent which would react with interesting compounds to a water sample in a reusable plastic tube.
Step 4: place the sample tube in a small plastic viewing box.
Step 5: find the part that best matches the color of the sample from the colour chart.
3.3 Digital instruments
Digital instruments could be used to measure chemicals in water. They provide the most accurate result
3.4 Colorimeters, Photometers
Colorimeters and photometers measure the amount of coloured light absorbed by a coloured sample in reference to a colourless sample blank. Photometers and colorimeters are similar but use different technologies to take the colour measurements.
Step 3: Adds a powder packet or a few drops of a liquid reagent which would react with interesting compounds to a water sample in a reusable plastic tube.
Step 4: Put the meter in the water and measure.
3.5 Arsenic test kit
Arsenic test kits provide colour reference charts, with reported detection limits around 0.01 mg/L. However, evaluations have shown that the results are an estimate, especially at lower levels (<0.1 mg/L).
Step 3: Follow the steps and pack the water samples back to the lab.
