NDWW -- The Day-to-Day Operation of a Water Company -- Water Treatment Processes
No one really thinks that much about their water supply, until one day, we turn on our faucet and nothing comes out. As we fume with shampoo in our hair, remember that, periodically, the water company has to flush the lines, to keep the quality of the water delivered in its peak condition. As you know, I work at a water companyand, while not privy to everything that goes on, Ive been there long enough to figure out a lot of things. So, while it is National Drinking Water Week, lets pay homage to all those men and women on the front line of producing a clean, safe water supply and delivering it to your door!
Weve discussed sources of your water supply in our last missive. Once the source water enters the treatment process, the water is ours, all ours! Mwah-ha-ha-ha-ha No, really, were the good guys! We serve the publics health, and work together to produce the best water we can, at the lowest cost possible!
Water treatment regimen for a Public Water Supply, (PWS), involve an industrial-scale process used to make water more acceptable for a drinking water supply. Few source waters are able to be used as a source of supply without some kind of treatment. The plant where I work produces an average of 45 million gallons of water every day! We are a groundwater plant, meaning that our source water is a groundwater supply.
The goal of all water treatment processes is to remove existing contaminants, or reduce the concentration of those contaminants so that the water is fit to drink, and meets both US EPA and State drinking water standards.
Substances removed during the process of drinking water treatment include:
- Suspended solids
- Bacteria
- Algae
- Viruses
- Fungi
- Minerals, such as iron, manganese, and sulphur, and
- Other chemical pollutants such as fertilizers, pesticides, etc. The REAL nasties.
The processes also include leaving residual disinfectants in the water in order to kill any bacteriological contamination during the distribution process
Processes from drinking water treatment include these listed below. These may be used singly, or in any combination to produce the desired effect. Not all treatment plants use all processes, because each treatment plant is designed to treat the specific source water.
- Pre-chlorination for algae control, arresting bacterial growth, and oxidation process for unwanted minerals such as iron, manganese, and sulphur;
- Aeration along with pre-chlorination for removal of dissolved iron and manganese, and the removal of sulphur dioxides;
- Coagulation use of Alum, Ferric Chloride, Ferrous sulfate, Ferric sulfate, or a Cationic polymer to alter the charge of the suspended particles in the water, this may be coupled with softening;
- Flocculation once the particles are charged, they tend to clump together for easier removal;
- Sedimentation basins are used to settle out the material before filtration;
- Filtration the treated water is gravity drained through graduated activated carbon, sand, and gravel filter to remove all the clumped particles;
- Desalination some areas use water that is high is salt and must be desalinated before it reaches the customer, and;
- Disinfection chlorine is added for killing bacteria throughout the distribution system. At this final point, fluoride is added to the water, as well.
Every treatment plant is different, and uses various parts of these processes to clean and disinfect the water that reaches your home. Typically, groundwater supplies require less treatment than surface water supplies, but may require pre-chlorination, aeration, and softening. Surface water supplies usually have a higher degree of particles in the water that must be removed prior to its arrival at your home. Our treatment plant started life as a surface water plant, and, even though we use wells now, the process we use is similar to a surface water supply.
Whos Who in the Water Industry
Many departments and personnel within the Water Company keep the water flowing through the treatment plant:
Operators operators must be licensed, (renewed yearly), in order to operate the pumps, valves, chemical feeds, and filters of the water plant. They accept deliveries of treatment chemicals, check the chemical feeds to make sure they are operating properly, gauge the amount of water running through the plant, plan for peak usage times, and oversee the entire process. The treatment plant is in operation 24 hours per day. They collect water samples for analysis, check the telemetry of all the operations of the treatment plant, and generally stay busier than a one-armed paper hanger.
Laboratory lab personnel include microbiologists who test the water for microbes, chemists, who test the water for chemicals, and other personnel whose main job is the testing of the raw water entering the plant, and at each step of the treatment process to make sure the process is operating effectively, and keep up with the ever-changing regulations on water quality, as well as other tasks. Every day, our laboratory personnel run over 5,000 tests on the water within the distribution system, as well as run required testing for daily, weekly, and quarterly reports for the Division of Water.
Maintenance maintenance personnel backwash and clean the filters, coagulation basins, and chemical feeds, make sure the back-up generators are working, maintain all equipment, unclog lines, work on pumps, valves, and fittings, and generally keep everything ship-shape so that the production of drinking water flows smoothly throughout the plant.
Engineering tweaks the process for variations in raw water quality, keep an eye on operations and maintenance, design small water lines for testing, keep electrical controls working, design additional controls, write specifications for additional work to be carried out at the treatment plants, test back-up generators and other systems, and oversee the general operations of the plant.
Source Water Protection Thats me! I work with the public education folks to protect the groundwater supply from potential contaminants, (Wellhead Protection), through educational activities. I also do other source water protection activities for the surface water supply. If there is a new gas station constructed in the Wellhead Protection Area, Im there to make sure they have met all state requirements, and have educational materials on Best Management Practices. I work with residences, businesses, and other government properties.
Purchasing orders and pays for the delivery of chemicals, equipment, and supplies, and works with contractors who work at the treatment plant to update infrastructure.
Legal develops contracts for contractors and sub-contractors, prepares legal documentation necessary for the operation of the treatment plant.
Risk and Safety Departments both departments work closely with one another to prevent injuries on the job, train personnel in emergency procedures, and provide appropriate safety equipment to personnel. Someday, Ill get my very own respirator! I hope.
Public Relations produces notices for the public about the treatment processes, educational activities.
IT Keeps all those computers working!
If you would like to see all the contaminants that are required for testing and compliance Go HERE to the US EPA drinking water standards page. MCL stand for Maximum Contaminant Level.
If you would like to see more information about fluoride in drinking water-- Go HERE .
If you would like more information about YOUR public drinking water supply-- Go HERE . This information will provide you with an address where you can contact your local water supply and request a Consumer Confidence Reporta report on the water quality delivered to your door!
Did You Know? Water Facts!
- The first municipal water filtration plant opened in Paisley, Scotland in 1832. The first municipal water treatment plant in the US, consisting of large sedimentation basins, was opened in 1862 at Louisville, Kentucky.
- Water managers in 36 states expect water shortages by 2013. California has a 20 year supply left, while New Mexico has only a 10 year supply left.
- Lake Mead has a 50% chance of going dry by 2021.
- 40% of US rivers and streams are too contaminated for fishing, swimming, or drinking because of massive toxic runoff from industrial farms, intensive livestock operations, and more than 1 billion pounds of industrial weed killer used in the country each year.
- Two-thirds of US estuaries and bays are moderately or severely degraded.
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WHAT a day! I burned my thumb rolling my hair this morning, and my thumb has a nice blister on it. Then, I thought I could sit on the nice new piece of driftwood at work, (which is a cypress root dug up in the new construction), and learned, alas, that I could not, as it tipped over on me, planting my face in the mulch. I grabbed a pair of pantyhose to wear to Peep's band concert, which had to be some of my oldest ones, and right during the Arabian Dances by Roland Barrett, the elastic gave away and I had to leave the building surreptitiously holding them up with one hand, shielded by my purse. We then met our fellow inlaws for a late dinner, and I managed to dump a newly opened packet of honey on myself at dinner. It hit the table, bounced, hit the bodice edge of my dress, spewing honey all over my, uh, "boobage", bounced, landed in my lap, and rolled off down into my purse. Honey was EVERYWHERE! All the way home, I could feel it trickling down, in spots...
It's good to be home!!!