Category Archives: Cholera Outbreak

Bad Water Part Two

Ft. Collins CO City Park Lake

Let’s continue with stories about what happens when pathogenic organisms get into a potable water supply.  Usually the causes of disease outbreaks are caused by no treatment or failure of the treatment process.  This one, however, is because of a cross connection.

Cross connections are when a treated water system is contaminated by water coming into it downstream of the treatment plant.  Garden hoses are a good example.  If the sprinkler head is in a puddle while in use and a negative pressure occurs, contaminated water can be sucked  Into the piping system.  Opening a fire hydrant in the area is a common cause.  Flow in the water main increases and the venturi effect can pull water from the garden hose into the main.  In big buildings, bad plumbing can let boiler or air conditioning into the building plumbing system.

Fort Collins, Colorado had a major cross connection event before I went to water-wastewater school there.  The lab people at the wastewater plant got a phone call one weekend.  The caller said several people in her neighborhood around City Park had gotten sick in recent days.  They went right out and sampled in several places.  Sure enough, the drinking water had coliform bacteria, a sure indicator of fecal contamination.   Much fire hydrant flushing ensued and a boil order went into effect.  All the testing indicated the water was still bad around City Park.  It occurred to someone to check with the Parks Department.  The park was irrigated with water from City Park Lake.  There were times when irrigation demand exceeded flow onto the lake and city water was used to supplement the ditch water.  This is from memory.  No online references.

There are backflow preventers to keep the systems separate.  You have seen those big brass devices in parks in your area.  Another method is an air gap.  City water drops out of a pipe above a tank where the water is collected and pumped out.  The air gap keeps things safe.  Well, the old tank had rusted out and someone just put in a piece of pipe. Lake water into city water.  There are lots of wild geese in Fort Collins using that lake.  Fecal-oral.

If you have been to New York, you have seen all those old water tanks on the top of buildings.  City water is pumped into the tank then the water is contaminated by sediment accumulated on the bottom of the tank or a hole allows birds and animals to enter the tank.

The worst example of a tank getting contaminated occurred many years ago in a water district south of Colorado Springs.  The maintenance people entered the hatch in the top of a several million gallon storage tank and discovered a dead body floating there.  No diseases had been reported, verifying the old water adage “The solution to pollution is dilution.”  I did a Web search on this event.  For some reason, there is not a word online.

Years later, the city of Alamosa, Colorado found coliform bacteria in the city water.  A boil order went into place and the search began.  The local water department was overwhelmed and Denver Water sent a team to help.  Much searching led to discovering the bad stuff was coming from a big storage tank that had seen no maintenance in years.  Usually storage tanks are regularly taken out of service and cleaned.  With Denver Water it is an annual practice.  That Alamosa tank had a lot of sludge on the bottom and a hole just under the roof where birds were entering.  Again, fecal-oral.

My experience along this line was when I was working at the Greeley, Colorado wastewater plant in the spring of 1979.  The Cache La Poudre had a huge spring runoff.  The flood washed out a pipeline in the plant that moved raw wastewater across the river.  The city’s untreated sewage went into the river for several days until an emergency pipeline was built.  The solution to pollution was in effect because flow in the river was at record levels.

Early in the twentieth century, many cities built primary wastewater plants to provide some treatment.  The wastewater went into big settling tanks where a lot of the solids were removed and the remainder went to the river.   Greeley did that.  There was an old pump that handled the sludge that went into service in 1926.  Secondary treatment came in, but during World War II, many systems shut the secondary systems down to conserve electric power.  Partly treated sewage in the river all over the country.  When the Poudre flooded, we had to wear hip boots around the plant.  The door to that old pump station was sandbagged to keep the river out.  The whole thing got rebuilt just as I left Greeley for Manitou Springs and away from wastewater plants.

Raw Sewage Into Stream

Growing up in Fruita, Colorado in the 1950’s,  my friends and I roamed all over the town.  Just southwest of town we were exploring a natural wash and discovered the sewage outfall for the town of  Fruita, population 1800.  Raw sewage went into the wash and to the Colorado River a mile downstream.  Gross.  There were lots of what we called in the wastewater trade “white trout” hanging from the bushes.  Some years later, the town built a sewage lagoon to treat the wastewater.

Well, I  think I have given you enough horror stories

 

Bad Water Part One

Giardia Lamblia Cysts

I spent thirty years in the water business, both water and wastewater.  During that time I learned about or saw many examples of what can go wrong.  There are the big ones such as Flint, Michigan where process and raw water changes sent corrosive water into a system with lots of lead pipes.  In Milwaukee, 1993, runoff from manure-laden agricultural land contaminated Lake Michigan water, the source for Milwaukee’s treatment plant.  Lots of people got sick from cryptosporidium,  a single cell organism resistant to chlorine.  The water was within standards, but that didn’t matter to the 400,000 people affected.  The big ones are the headline makers but there are many other outbreaks, usually in small water systems.

First, I must point out that water treatment starting around the start of the twentieth century is the single greatest public health advance in history.  Chlorination along with a good sedimentation and filtration process are the weapons.  We can be grateful we almost always have clean, safe water coming out of the tap in most of the developed world.  This is not so in much of sub-Saharan Africa, Haiti, and now Puerto Rico.

In 1854, the source of a cholera outbreak in Soho, London was traced to a single well which was contaminated by a nearby cesspit.  Taking the handle off the pump ended the outbreak.  This was the first scientific validation of the germ theory of disease.  The main theory at the time was that disease was borne by miasma, bad air.  Later, chlorine was introduced as the main barrier to waterborne disease,  along with filtration.

Things mostly went well.  Government regulation insured drinking water would be treated.  Here in Colorado, however, there is a confounding variable.  Our pure mountain water can transmit Beaver Fever.  The technical term is Giardiasis, caused by a single called organism called Giardia Lamblia.  These little critters, like Cryptosporidium, have a cell wall tough enough to resist chlorine in the concentration which reliably kills  bacteria and viruses.

Like most waterborne diseases, transmission is fecal-oral.  People drink water containing feces from warm-blooded animals.  The reliable way to eliminate the pathogens is a well operated complete treatment process which removes the cysts.  Ultraviolet light also kills them.  Denver, for example, has never had a Giardia outbreak, even while treating more than 400 million gallons per day in summer.

There are pitfalls, especially in small water systems.  Plant operators are required to have certification from the state health department, but many rural operators have a weak science background and passed the written tests by studying test questions collected by pervious test takers.  The head of the water department may be the mayor’s brother in law or a good old boy who does what they have always done and may cheat on the lab tests and paperwork.

A good example was in 1979 in Estes Park, Colorado.  People started getting sick, often tourists who had returned home before becoming ill.  Giardiasis is a nasty disease.  Cramps, raging diarrhea, and a violent headache.  After a few days, the symptoms subside, only to return a couple of weeks later.  The cause? The old guy running the plant saw the water from Rocky Mountain National Park  was so clear in late summer he turned off the chemical feed used to trap Giardia cysts so the filters can remove them. The cysts went right through the filter.

I had a partner I worked with in the Greeley wastewater plant who got Giardia.  She was a bit doctor resistant and didn’t go in until after the third bout.  There is a medicine called Flagyl that cures the disease in a few days.  She had gotten so weak her immune system didn’t recover fully for a year.  She came down with every little disease that came along for that year.  The county health department tested all the staff.  I was positive for amoebic dysentery, but symptom free.  We worked around big open tanks with mechanical aerators flinging the water in the air to bring up the dissolved oxygen level enough to grow the beneficial organisms that ate the bad ones.  We breathed that aerosol.  I didn’t occur to anyone to use masks around the tanks.

There is the reason for wastewater treatment.  The process removes or kills most of the bad guys before the water goes into the river.  Thus, people using the water downstream don’t have as much of a mess to clean up.  Think about Mississippi River water in New Orleans.  Safe drinking water can come from the river if treated.

For many years, many systems relied solely on chlorine to insure safe drinking water. New York City  still does.  Seattle used to do chlorination only, but now treats the water (one of the plants using ultraviolet disinfection.).  I was one of the first persons hired by the City of Manitou Springs, Colorado to operate their new treatment plant.  Prior to building the plant, All they did was chlorinate.  The water was from the north side of Pikes Peak and of high quality except after summer thunderstorms.  Then, people got sand and pine needles out of the tap.  Risky, and the health department demanded a treatment plant.

Stay tuned, more to come.