Biosolids Corner Snippets November-December, 2004 Measuring pH in BiosolidsIf your biosolids treatment process relies on lime or alkaline addition to achieve pathogen reduction or vector attraction reduction, you are probably running frequent pH tests. According to Denise Uzupis, PADEP Central Office, there are often misconceptions about reporting pH corrected to 25 degrees Centigrade. Both the USEPA and PADEP regulations require that the pH reported be corrected to 25 degrees C. What causes confusion is that many pH meters have a feature called temperature compensation. If your pH meter does not have the temperature compensation, you would have to keep your deionized water and biosolids mixture at exactly 25 degrees C (77 degrees F) in order to measure pH accurately. If the pH meter has the temperature compensation feature, you can measure the pH at any temperature the mixture happens to be. However, this reading must then be corrected to 25 degrees C using a calculation. Knowing the temperature of the sample of biosolids, use the following formula to determine the actual pH needed to achieve lime or alkali stabilization.Correction Factor = 0.03 pH units x (25°C T°C measured) pH measured = ph measured + correction factor You can also use the chart on page 4-12 of the Department of Environmental Protection Biosolids Training Workbook to correct pH to 25 deg C. For more details on measuring pH go to the PADEP website, click on Subjects, click on Biosolids, click on Training and Technical Information for Generators and Appliers, click on Job Aides (top left of screen), click on Measuring pH Worksheet, scroll down and click on measuring pH of a sample, answer multiple choice questions and there you have it! The reason for the confusion may be that the web site uses the word compensated instead of the word corrected!During this voyage into the entrails of the DEP web site you may also see other interesting facts. Did you know that the pH meter should be a potentiometer and it should be calibrated daily? Or that the probe should be soaked in 0.1 N hydrochloric acid (HCl) for 15 minutes weekly? Or that the probe should be kept in pH storage solution (potassium chloride, KCl) when not in use. In addition, all meters must be able to measure to the nearest 0.1 pH units. Thoughts About the Work of Water Quality ProfessionalsIf you made it this far into this article without falling asleep you deserve a pat on the back. Whether you work at a plant, a regulatory agency, an engineering firm, a laboratory, provide equipment and services, or volunteer for stream clean up, you are all improving water quality. How important is that? The following provides amazing facts you may have overlooked that emphasize the importance of the work you do. Throughout the world, there is a shortage of clean water. The World Health Organization estimates that 10,000 children die everyday because they do not have enough clean water to drink.In America, Money Magazine does an annual survey to determine the factors most important to our quality of life. For the last 10 years, Clean Water has been in the top five factors contributing to a high quality of life.There is nothing simple about water. Ask yourself, what color is water? It is clear, but if it is deep enough it appears blue. This color can change to green or brown or any color depending on what else is in the water. When subject to turbulence it is white. In a lake it can reflect the colors around it, or sparkle in the sunlight. Nothing can evoke such a wide range of emotions as water can. The sound of a babbling brook or waves slapping on the shore can cause us to relax or be content. The sound of a leaky faucet can result in aggravation. Flooding waters can invoke fear, whereas water in the desert provides life saving relief from thirst. Polluted water causes us to recoil and instills resentment towards those who have contaminated it. No other material on earth serves so many uses. We use it for drinking, cooking, cleaning, cooling, disinfecting, sanitation, heating, transportation, manufacturing, power, recreation, fire fighting, irrigation, as a habitat for fish and plankton (organisms that produce most of the oxygen in our atmosphere.) Water is essential for all forms of life on earth. In fact, when astronomers look for signs of life in outer space, the first thing they look for is water.So what value is placed on those who cleanse that water, which has cleansed, nourished and enabled civilization? What value is placed on those who return it in its purified form to the world to be used again for the benefit of mankind and all Gods creatures? (Thats you, dear reader, and I think you are under appreciated.)No other material has caused so much death or destruction. Without proper treatment, disease can wipe out a population. Flooding, mudslides, rain, snow and drought have caused incalculable damage and loss of life.The importance of water is recognized in all cultures and virtually every religion uses water to symbolize a variety of lifes experiences. Throughout religions of the world, water symbolizes purity, cleansing, rebirth, renewal, initiation, youth and eternal life. Virtually all religions and scientists believe that in the beginning there was water, the earth was formless and empty. There was no sky and no dry land. Water has all the mystery, challenge and magic of the world hidden in it.As scientists, we see the sublime molecular framework namely the intensely stable and chemically potent coupling created when two hydrogen ions combine with oxygen. This bonding makes water one of the most common materials on earth. Water defies physical laws; it has a myriad of laboratory characteristics that make no scientific sense. It doesnt freeze or boil at the temperature one would expect. It is the only substance able to exist on earth naturally as a solid, liquid and a gas. As a solid it is lighter than its liquid form. Waters molecules are corrosive enough so that given time it can disintegrate the toughest metal. So benign, that life forms of all types flourished in it; in fact, life could not exist without it. Waters own molecules, like magnets, draw to each other more tenaciously than certain metals. In so many ways water is a fear and a fascination. It is no wonder that so many religions look towards water as a foundational metaphor. We can see water for what it most truly is -- a mystery, big and small. |
