Treatment Plant Tours- Des Moines Water Works
I. Organize group. Welcome them to the Water Works.
A. 3 water sources at Fleur Plant :
1. Raccoon River -adjacent to plant
2. Des Moines River - 5 mile pipe – intake at Prospect Park
3. Infiltration Gallery (underground water filtered through sand and gravel in
banks of river and underneath ponds in Water Works Park), 3 mile pipe
(concrete rings spaced very closely together), 48” diam., approx. 35 ft. below
surface to catch filtered water (narrow slits in top); gallery pumping station
built in 1918 to recharge ponds; pump water from Raccoon River into ponds
B. Other DMWW water resources
1. L.D. McMullen Treatment Plant – SW of town – nine radial collector
wells that collect water from banks of Raccoon River -15-25 mgd
2. Maffitt Reservoir – SW of town – used sometimes in summer only
3. Saylorville Treatment Plant – wells – located between Ankeny and
Johnston - uses nano and ultrafiltration (reverse osmosis) for removing
contaminants
II. West Low Lift/ Presedimentation Basins
A. Pump water out of the rivers to the treatment plant.
15 mgd
30 mgd
40 mgd
B. 2 underground pre-sed basins (size of football field and about 2 1/2
stories tall)- each one can hold 4 million gallons of water (same amount as in
Tenny Standpipe at Merle Hay Mall by Sears store), keep water at 35

- 60

(above freezing in winter and cooler in summer).
C. Powdered activated carbon is added to remove bad tastes and odors and
pesticides (for example, gasoline and animal waste).
D. Basins divided into 3 chambers or rooms –
1. water is mixed with chemicals by flocculators (look like large mixers)
2. ferric chloride is added to make dirt and sediment clump together and drop
to bottom of basins where it can be scraped away by flightboards (almost
like a row of snowplows); mud is pumped through pipe leading across river
to land DMWW owns- hope to build a wetland there eventually
3. remaining water moves onto the lime softening basins .
III. Treatment (Softening) Basins
A.
4 basins - each one can hold 4 million gallons of water.
B.
Water in Iowa is very
“hard”
because it contains many minerals, mostly calcium and magnesium, which make the water hard to clean with. Water has a lot of minerals in it because Iowa was once covered by shallow, warm seas; the climate changed, the seas receded and left behind many shell animals which were buried under heat and pressure for thousands of years and formed limestone. Limestone readily dissolves in water and makes the water “hard.”
When you try to clean with hard water, the soap gets attached to the minerals h:\educate\tours

instead of the dirt, so you have to use more soap and you still end up not feeling as clean. The minerals are also removed to improve the taste.
C.
Infiltration Gallery water brought in to mix with river water from presedimentation basins. Gallery is a 3-mile pipe lying about 30-35 feet below the ground in Water Works Park that collects water that has filtered through the layers of sand and gravel in the bottom and banks of the Raccoon
River, as well as through the bottom of the ponds (recharge basins) that
DMWW has put in the park to augment the water supply to the Gallery.
Pumps next to the river pump river water into the ponds.
D . Lime is mixed with water to form a lime slurry, which is fed from the
chemical building (top of Filter Building) by gravity through underground
pipes into the softening basins. Lime removes hardness minerals (mostly
calcium and magnesium that is dissolved in the water) to soften the water.
Softer water does not require as much soap or detergent to make a good lather.
Because of the high pH of lime, 99.9% of the bacteria are also killed during the
softening process. Carbon dioxide (CO
2
) is added to lower the pH level at the
end of the softening process.
E. Ferric chloride is also added as a coagulant (and sometimes alum) to make the
dissolved minerals that make water hard clump together and fall to the bottom
of the basins where flocculators push the minerals into a pipe leading to the
dewatering facilities.
F. Some minerals are left in the water to provide a protective coating on the
inside of pipes in the distribution system. This makes it more difficult for lead
to leach into the water supply.
G. Sludge Dewatering Facility (this building is pointed out and not actually
toured)-The sludge mixture that is removed in softening basins is pumped to
the silver-domed building to thicken, then into the dewatering facility where
the water is pressed out by fabric-lined presses forming cakes that are about
5’ in diameter and are dropped into semi-trailers awaiting on the lower level of
the building (about 8-10 semi-loads per day), where it is then transported to a
company that further dries the sludge so it can be used for land application
( A glime raises soil pH - Iowa has slightly acidic soil); other potential uses
include reclamation of abandoned mines and stabilization material for landfills.
The facility normally operates 16 hours per day, 6 days per week, but time can
increase in the summer months.
IV. Laboratory – (lab personnel will deliver this part of the tour)
A. Bacteriological (microbiological) laboratory - test for the presence of
harmful bacteria, viruses, and protozoa in the raw water, at different points in
the treatment process, in the finished water, and in distribution system; also
perform testing for local pools and spas and many of the suburbs.
B. Chemistry laboratory - mention various equipment used for testing
pesticides, lead, etc.; also the wet chemistry area where they perform many
basic chemical tests such as titrations, check the pH level, taste and odor, etc. h:\educate\tours

V. Filter Building - east wing built in 1949 and west wing in 1959
A. 16 sand and gravel filters - each one contains about 100 tons of gravel, 130
tons of sand; approximately 4-5 feet of water is brought in on top of 2 feet of
sand and 2 feet of gravel; approximately 50,000 gallons of water in each pool;
water slowly moves down through sand and gravel where tiny particles of lime
or dirt get trapped, leaving clean water to flow out the bottom of the basins into
awaiting pipes.
B. After a filter has been in operation for about 40 hours, a backwash is
performed to clean the sand and gravel; the pool is emptied and water and air
(the green tank is the air tank) are forced up through the bottom of the filter to
stir up any dirt, lime, etc. that is coating the sand and gravel or has settled in
the basins; it takes about 100,000 gallons of water to backwash one filter; this
“dirty” water is recycled back to the softening basins; this process takes about
30 minutes and is controlled by computers in the Control Center.
VI. Nitrate Removal Facility (usually have students sit on edge of a couple tanks –turn
on Clear Well lights when enter room)
A. Became operational in February 1992. Largest in world.
B. Nitrate concentrations in the Raccoon and Des Moines Rivers are our biggest
water quality problem. Sources of nitrate are fertilizers, decaying organic
matter, and sewage; during certain times of the year, especially springtime,
high levels are found in the rivers. As a utility, we must keep the level in our
finished water below 10 ppm (parts per million or mg/liter); levels above 10
ppm can be harmful to children under the age of six months by causing “ blue
baby syndrome” – nitrate converts to nitrite and makes it difficult for
oxygen to be carried through the baby’s bloodstream, thus, they can’t breathe.
C. When the facility is operated, an ion exchange process occurs , i.e. nitrate
is exchanged for a chloride (positive and negative charges attract); this process
doesn’t remove nitrate entirely, but it does bring it down to an acceptable level.
Costs around $6,000 per day.
D.
Flooded during Flood of ‘93
VII. (optional info) Nitrate Removal at Crystal Lake
In 2004 DMWW began testing an environmentally-friendly method of removing nitrate from our source water at Maffitt Reservoir. The concept is called off-river storage. River water is diverted into Crystal Lake where the tranquil water is conducive to the life-processes of microorganisms that can remove nitrate from the water. No chemicals and very little energy is used to remove nitrate in this manner, and no waste is discharged back into the river.
This process continues to be very successful in removing nitrate both at
Crystal Lake and at the ponds in Water Works Park.
VIII. Chlorine and Fluoride
A. Small amount of chlorine is added for disinfecting purposes in case any germs
have made it through the treatment process and to keep the water safe
throughout the distribution system.
B. Fluoride is added to help in the prevention of tooth decay. h:\educate\tours

C. Very small amounts of both of these chemicals are all that is needed.
IX. Clear Well
A.
10 million gallon underground tank that holds treated water
B.
approx. 20 feet deep
C.
looks blue/green because of blue DMWW symbol in the tile at the bottom
D.
flooded during Flood of ‘93
X. West High Lift Pumps (located NE of the nitrate removal facility)
A. These pumps pump water out of the clear well and into the distribution system
30 mgd
30 mgd
20 mgd
-we see the ventilators, not the pumps
B.
Flooded during Flood of ’93
C.
Levee is now 31’ (was 24” in 1993) – also put in flood gates at entrance to plant
XI. Emergency Generator
A. Operates using diesel fuel
B. Purchased to provide power in an emergency situation.
D.
When power goes out, generator will automatically come on in 10 seconds.
E.
Largest in North America
F.
Provides over 3 million watts of power. It has a horsepower of 5,500 hp (a car is under 200).
XII. Control Center – (just point out)
A. Our operations at both Fleur and L.D. McMullen Treatment Plants can be
monitored from this room, such as chemical feeds, water tower levels,
pressure, sludge dewatering presses, backwashing, etc.
B. A Control Center Operator is on duty 24 hours a day.
C. Control Center is on 2nd floor to provide flood protection.
D. SCADA system provides computerization of the operations at both plants
XIII. Pumping Station - East High Lift
A. Was built in 1921
B. Contains high service pumps = 2 electrical (15 mgd each) and 1 diesel
(25mgd)
C.
Capped pipe in SE corner left from time of steam-driven pumps. Could connect to electric pump at some time to increase capacity. h:\educate\tours

XIV. East Low Lift-down tunnel in pumping station (do not visit)
A. Contains gallery water pumps
XV. Miscellaneous
A.
Could briefly tell students about Fabrication, Vehicle Maintenance,
Distribution and Service Building.
B.
Average pumpage is about 45 mgd.
C.
Record pumpage was 95.64 mgd on July 23, 2012
D.
Entire treatment process takes 15-21 hours.
E.
All chemicals DMWW adds to the water during the treatment process, except chlorine and fluoride, are removed during the treatment processes.
F.
DMWW delivers water to an area that includes about 500,000 people.
G.
Des Moines Water Co. began pumping gallery water to Des Moines customers in 1871. City bought DMWW in 1919 and began construction of present pumping station.
H.
Infiltration Gallery was the sole source of water until started using the
Raccoon River in 1949.
I.
Lab started in 1912 and began adding chlorine to gallery water that same year.
J.
Started adding fluoride in 1959.
K.
Water Works Park is about 1,500 acres (largest inner city park in US).
L.
DMWW owns and operates 6 water storage facilities:
Hazen Tower – 2 mg
Nollen Standpipe – 4 mg
Wilchinski Standpipe – 2 mg
Tenny Standpipe – 4 mg
Louise P. Moon Storage Tank – 6 mg
Polk County Storage Tank- 5 mg
Total Storage Capacity- 23 mg
DMWW also stores water in two places in underground aquifers in
Ankeny as well as in an aquifer at the Louise B. Moon Storage Facility in
West Des Moines and another at the L.D. McMullen Treatment Plant .
Water is pumped into the aquifer during the winter months and pumped out in
the summer during times of high water demand (a small amount of chlorine is
added before it is pumped to customers). This is called Aquifer Storage and
Recovery (ASR).
M.
There are over 900 miles of water mains in Des Moines.
N.
There are about 7,750 fire hydrants in Des Moines. h:\educate\tours