With the public outrage and tough laws against water pollution caused by industrial waste water, all factories are now strictly controlling discharge of waste.
Currently, each local government designates water-quality standards and enforces restrictions. The pH of discharged water is one of the most measured items under water-quality regulations. Although pH does not necessarily indicate a particular kind of pollution, it is closely related with the survival of aquatic life. Abnormal pH can cause settling of halomorphic compounds and pollution of water.
Also, each factory is required to treat its waste water to conform to the quality standard for waste water. Measuring pH is important in this process, too. For example, at a plating plant, treatment efficiency is greatly affected by pH of the processing solution when removing cyanide or chromium from waste water.
The pH of the water used in all the boilers, including those large boilers used at thermal power plants is maintained above 8 in order to prevent corrosion of pipes. The boiler water is also kept alkaline to prevent corrosion. However, if it becomes too alkaline, a calcium oxide is formed, which is caustic and adheres to the wall of the boiler. Thus, pH is maintained at about 9.4 in the boilers of thermal power plants.
With today's high-performance, high-efficiency boilers, control of the water becomes critical, and pH control of boiler water is conducted not only at power plants, but in a wide variety of fields.
In the gas industry, the pH of the water in liquefied gas is controlled in the mixing process to enhance caloric potential and prevent corrosion of tanks and pipes.
At filtration plants, water from rivers and lakes is disinfected with chlorine, and impurities are settled out and filtered out and removed with the aid of an agglutinating agent. At this stage, the pH of the water is maintained at a value appropriate for the action of the chlorine and the agglutinating agent.
Naturally, before this water is supplied to homes and commercial and public facilities, alkaline is added to neutralize it so it will be appropriate as drinking water, etc. At sewage-treatment plants, pH is measured not only in each process and at the time of the release after treatment, but also in adjustment of pH to optimize the activity of bacteria in sludge when using the activated-sludge method and treatment of generation of bubbles from the active agent.
*Scientific criminal investigation by police
Science plays an important role in modern criminal investigation. Measuring pH is helpful in determining a victim's time of death.
*Merchandise testing at department stores, consumer centers
Testing facilities of department stores and consumer centers conduct quality checks of merchandise so that consumers can buy, use and eat the merchandise without worry. Measuring pH can tell them the permanence of dye in a fabric or the freshness of food.
Measuring pH is essential for plant physiology, too. For example, pH is measured when experimenting with plant breeding and in the study of color change of flowers.
For fashionable hair styles, cold-waving liquid plays an important role in achieving such beautiful waves. At beauty salons, pH is regulated in the cold-waving liquid according to hair type and wave.
Bright green lawns grow with grass of uniform height, and contribute to enjoyable golfing. To keep the lawns in top condition, greens keepers check the pH of the soil and provides necessary care accordingly.
*Photo developing labs
Controlling the pH of the developer is a very important part of faithful color reproduction--of skin tones, the bright red of a flower, the blue of the sky. For color negatives, the pH value of developer varies from 3 to 12, depending on the developing process. A slight variance in pH can cause a difference in colors.
A clear blue sky seen through clean windows and shiny office floors will enhance the efficiency of your work. However, the precious wax will become cloudy if one does not completely remove the alkaline ingredient within the remover and detergent.
As you can see from this example, pH is an important factor in our daily lives.
The concentration of residual chlorine and the pH value are important items in controlling the water in swimming pools.
In fact, pH is measured in more fields than we have room here to list.