What is it & why is it Important?
It is a measure of how acidic or basic a solution. The pH scale goes from 0 to 14 with 7 being neutral and anything below 7 is considered acidic and anything above considered basic or alkaline. It is a measurement of the concentration of hydrogen ions. There are a couple of important things that pH affects one being corrosively, which can severely damage plumbing and water appliances such as dishwashers and water heaters and can cause bluish green staining from the copper being dissolved. Another thing to consider is pH will significantly impact how water can be treated effectively.
Is pH Regulated?
The EPA regulates pH as a secondary contaminant, which means it is more of a guideline than an enforceable level. The EPA recommends pH to be between 6.5 and 8.5 standard pH units.
When water is exposed to the atmosphere, it has a tendency to take in carbon dioxide, some of which can react with water and in turn forms carbonic acid and H+, and lowers the pH level, thus it is important to measure pH immediately after sample collection.There are a couple of ways for determining pH levels. Many utilize pH indicators to get a general idea of the pH level. Indicators are chemicals added to the solution, which produce a color change, which is related to the level of pH. Unfortunately color is very subjective which can lead to imprecise reading of pH levels.
If a more accurate pH level is needed, one should consider a pH meter. pH meters utilize a glass probe, which produces a certain voltage based upon the pH level of the solution being measured. It is important to properly calibrate your pH meter to ensure a high level of accuracy. Meters should be calibrated based upon their usage. If used frequently, like in a laboratory it should be calibrated more frequently than is used less often. It should be calibrated using at least two buffers if not three. A buffer solution with a pH level of 7 is used along with one of 10 if the solution is suspected to be basic or a buffer with a pH of 4 if the solution is suspected to be acidic. If you are unsure of the general pH level it is best to calibrate using all three buffer solutions. To calibrate place the probe alternately in two solutions until the meter obtains an accurate reading, most modern meters will only need a single immersion to get an accurate reading. After the meter is calibrated, the probe should be rinsed using deionized or distilled water and blotted dry with a clean tissue, then quickly immerse into the sample. Treating pH
Water with low pH levels are typically treated either by passing the water through a bed of chemically reactive media such as a calcite tank or via feeding a liquid chemical such as a solution of soda ash. Keep in mind the addition of elements as a result of treatment may cause the water to hard, which may require additional treatment such as water softening. High level pH is commonly treated using a chemical feed of a weak acid solution.