Posts Tagged ‘Water Treatment’August 21, 2013
On August 20, the Iowa Environmental Protection Commission (EPC) held their regularly scheduled monthly meeting at Des Moines Water Works (DMWW). Prior to the business meeting, Commissioners Couser, Rastetter, Sinclair, Smith, and Ver Steeg, Iowa Department of Natural Resources (IDNR) staff, and representatives from environmental and agricultural organizations toured Des Moines Water Works’ Fleur Drive Treatment Plant to gain a better understanding of the treatment process. DMWW staff provided the Commissioners an insight into the condition and challenges of source waters used for drinking water for the more than 500,000 people in central Iowa.
Challenges expressed by DMWW included everything from high nitrates to flood events. However, most questions and comments stemmed from the exceptionally high nitrate levels this year. DMWW staff emphasized that even if nitrate levels are currently low, the combination of nitrates and phosphorus in the rivers and increasing temperatures will again challenge DMWW due to algae blooms. Algae can cause taste and odor problems and require additional filter maintenance, which slows the treatment process and reduces production capacity.
The EPC is a panel of nine citizens who provide policy oversight over Iowa’s environmental protection efforts. EPC members are appointed by the Governor and confirmed by vote of the Senate for four year terms.
View this important video about Des Moines Water Works’ locate program, water infrastructure and treatment process.
Video produced by Iowa One Call.Labels: Des Moines Water Works, Des Moines waterworks, DMWW, Iowa One Call, Water Treatment Posted in About Us, Customer Service, Customers, Water Treatment May 1, 2012
Des Moines Water Works (DMWW) has utilized two Aquifer Storage and Recovery (ASR) wells as sources of water for four years. These wells are installed deep into the Jordan Aquifer and used to store water that is needed when water demand is high – usually during the summer months when customers are using more water for irrigation of lawns and gardens. When water demand is low, mainly during winter months, DMWW will store drinking water down into the wells which displace the native Jordan water around the wells.
A total of 270 million gallons can be stored in each of two ASR wells during the winter months when DMWW has excess water treatment capacity. Then in the summer months, during higher water demand, the drinking water is pumped out of the ASR wells and into the water distribution system for use by customers. The water is pumped out of each of the ASR wells at three million gallons per day rate. These wells can pump for a total of 90 days to recover the 270 MG put into the wells.
The ASR wells can be constructed for about one-third the cost of adding capacity to an existing water treatment plant. These ASR wells are utilized to take capacity demand off the treatment plants.
This is just one of the methods DMWW uses to maximize the funds used to invest in the infrastructure required to deliver quality water to our customer in the quantities that they need.
Some people are more sensitive to subtle changes in taste or odors. Des Moines Water Works (DMWW) uses the Raccoon and Des Moines Rivers as water sources. By using surface water, there can be some seasonal variations that occur. The treatment process should eliminate the variation in finished water, but sometimes there will be a slight change some customers may notice. For example, there may be a slight increase in smell or taste of chlorine at times, especially during a river’s spring thaw. This is easily remedied by storing water for drinking in a pitcher in the refrigerator.
If you think you have an issue with taste and odor of the water in your home, there are a few things you can do to determine the source of the problem. Check to see if the problem is apparent in all fixtures of the home. For example, is the issue apparent in the bathroom, kitchen and laundry room utility sink? Many times the issue is only at one fixture. This would indicate the cause is something in the household plumbing. A few things to consider would be: Has there been a recent change in the household plumbing? Do you have an in-home water treatment device that needs regular service or filter changes? Plastics can impart flavors and odors to the water; this can include parts in the faucet, plumbing lines, or appliances. If the problem is present in all fixtures, try running the tub or shower faucet for a period of time and then recheck to see if there is still an issue.
If it is an odor issue, try pouring a glass and then smelling it in another room. Sometimes the odor may be coming from another source, possibly a drain or garbage can, in the same room. By eliminating this possibility, one can ensure that it is the water that contains the odor. If you notice a sulfur odor, it may be from your home’s hot water heater. If the temperature is not set high enough, bacteria can grow in the water heater. A possible solution for this would be to turn the heater up high for a couple hours then return the setting to a normal level. If this is done, please use caution the first few times water is turned on, as water could still be hot.
If you are storing drinking water for convenient use, here are a few things to help prevent taste and odor issues. Store water in a glass container, as plastic can impart taste or odors to the water. Also make sure the container has a good seal. Store in the refrigerator as water will have less flavor when chilled. If the water has sat for a while, it may be flat. If this is the case, pour it back and forth between containers or shake it to help aerate the water. This will help to add oxygen to the water and remove the stale, flat flavor.
If you are still experiencing problems, please call your Des Moines Water Works at 283-8700 and report the issue and the duration the problem has been apparent. We will work with you to diagnose the problem.
This fall, Des Moines Area Community College (DMACC) began offering a new curriculum at its Ankeny campus. Thanks to a joint effort between an industry-wide committee (including American Water Works Association-IA Section, Iowa Water Environment Association, Iowa Rural Water Association, Iowa Association of Municipal Utilities, and Iowa Department of Natural Resources), this new curriculum has been designed to help educate a future workforce to fill the large number of openings expected in the water and wastewater industries due to retirements.
There will be three areas of study: water, wastewater, and a combination water/wastewater embedded in a larger two year AAS Degree industrial program. There will be three levels of education available; a Degree, a Diploma, and a Certificate of Specialization. By embedding into a larger industrial program, DMACC won’t have the pressure of keeping numbers of water/wastewater students up in order to keep the program alive (which has been an issue in previous programs across the state). When the number of students allows it, the water/wastewater program will be offered by other community colleges around the state.
The curriculum will be “in class” and “web-based” to reach both traditional and non-traditional students. The web-based students will attend one day of concentrated classes a week on campus. This allows students who are working, to take classes while continuing their employment.
DMWW assisted DMACC with the program and course design and will assist the instructors with assessment review. Des Moines Water Works is excited to have this new water/wastewater curriculum available to our employees and future employees.
- Samples of source water are taken prior to the treatment process on a daily basis.
- The samples are then placed in containers, such as petri dishes or pouches with numerous tiny capsules, along with “media,” a substance that acts like food for the bacteria.
- The samples are then left to incubate for approximately 24 hours.
- During this time, a bacterium can multiply from one to millions, making a colony that can be seen by the human eye in the culture plate.
The laboratory tests specifically for Coliform bacteria. Coliforms can be counted on a grid in the petri dish. E. Coli is grown in pouches with wells of medium. When placed under an ultraviolet light, the E. coli flouresces to a blue color indicating how many are present.
These tests are done before treatment and are indicators of the absence or presence of potential contamination in the water sample. All new water mains are tested for bacteria and must be free of all harmful bacteria before they are put into use.
The lime treatment process used by Des Moines Water Works kills 99.9 percent of bacteria and a chlorine additive eliminates anything that might be left, ensuring that your tap water is Water You Can Trust for Life.Labels: Des Moines Water Works, Des Moines waterworks, DMWW, E. Coli, Laboratory, water quality, Water Treatment Posted in Water Quality, Water Treatment August 16, 2011
When it comes to CaCO3, otherwise known as limestone, some like it hard and some like it soft. Water hardness is the amount of soap precipitating minerals in the water. The harder the water, the less effective soap will be.
Since 1948, lime softening has been a part of the treatment process at Des Moines Water Works. Powdered lime is mixed with water, forming a slurry, or thick liquid. This mixture is then fed into the four lime softening basins. As the water passes through the softening process, the lime slurry attaches to excess minerals in the water forming a lime floc. The limestone floc then settles to the bottom of the basins as by-product.
This process is beneficial for several reasons. First, removing the minerals helps lessen the hardness of the water, which allows detergents and soaps to clean better. Lime softening also kills harmful germs and bacteria, and causes a thin protective coating to form on the inside of pipes. This coating inhibits leaching of lead from older pipes into the drinking water supply.
DMWW strives to maintain the total hardness of drinking water to less than 150 mg/L. This equates to 8.76 grains of hardness on a water softener setting. Individuals who prefer softer water may consider purchasing and installing a water softening unit in their home. However, excessively soft water is very corrosive to your pipes.
There is no adverse health effect associated with hard or soft water – it’s just a matter of personal preference. You can get daily water hardness readings from DMWW’s lab reports.
Ignorance can be bliss, but most of us would like to be informed about what we are drinking. For this reason, Des Moines Water Works (DMWW) makes a conscientious effort to share with our customers all of the details pertaining to their drinking water system. Sometimes, the news isn’t always good!
E. coli is a species of bacteria found in the intestinal tract of vertebrates. DMWW lab staff regularly looks for them in our source waters and in our treated drinking water. E. coli is used as an indicator that water is potentially contaminated with human and animal waste, and therefore possible disease organisms. Not even one E. coli bacterium can legally be present in drinking water, according to the Environmental Protection Agency (EPA) standards. The numbers in source water can vary from zero to an amazingly high number in both the Raccoon and Des Moines Rivers. Des Moines Water Works relies heavily upon these two rivers as sources for fulfilling the Metro area’s daily demand for water. E. coli values over 2 million colonies/100 millimeter are present at times in some of the smaller streams that feed into our rivers.
DMWW’s extensive and rigorous treatment process physically removes or kills all of these bacteria before the water is delivered to customers. Nonetheless, customers should be aware of the water quality present in Iowa’s water resources, which are the source of drinking water for the state’s residents.Labels: Des Moines Water Works, Des Moines waterworks, DMWW, E. Coli, Source Water, water quality, Water Treatment Posted in Water Quality, Water Treatment February 10, 2011
Water from our rivers is “hard,” meaning it has a high mineral content, especially calcium and magnesium. This is because 100 million years ago, what is now Iowa, was under the surface of the ocean, and large limestone deposits are the result. As rain water and snow melt trickles through the limestone, toward shallow groundwater and eventually into our streams, it dissolves mineral deposits. Hardness is reduced in DMWW’s treatment plants using a process called lime softening.
The river water has a high nutrient content, especially nitrate-nitrogen and phosphorous. Some of the fertilizer used for crops is washed away or enters the streams through agricultural drainage tiles. Our super-rich soils also contain a lot of natural nitrogen and phosphorous, which is liberated from the soil during cultivation. The Raccoon and Des Moines Rivers have the highest and second-highest nitrate concentrations of the 42 largest Mississippi River tributaries. DMWW operates the world’s largest nitrate removal facility at its Fleur Drive Plant.
Our rivers have a relatively high level of sediment. Erosion is a natural process that has been greatly increased by both rural and urban land uses. It’s likely that most Iowa streams ran much clearer prior to settlement than in the present day. Loss of native perennial vegetation and increased streamflows because of human modification of natural hydrology, along with changes in land use and climate, are the primary culprits for increased erosion. In addition, levees have divorced streams from their floodplains, increasing river energy during high flows. This helps the stream scour sediment from the stream bed and banks. DMWW removes about 20,000 pounds of sediment (1,400 pounds per million gallons) from the treated river water every day, so the water will be clear and safe to drink.
Although DMWW’s source waters are considered impaired, DMWW is continuously adapting its treatment processes to deliver Water You Can Trust for Life.