Public Health Implications of Water Supply Improvements

Monroe L. Weber-Shirk School of Civil and

Environmental Engineering

Public Health Implications of Water Supply Improvements

Did Environmental Engineers save the world?

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Public Health

Environmental Engineers help protect communities from waterborne disease

Water related Public Health is complexHygiene, education, Chlorine may be overratedHousehold infrastructure matters

Reflections on skepticism, engineering, and love

The role of Water Supply, Sanitation, and Hygiene (WASH)

Contribute significantly to mortality and morbidity on the global level

Have an enormous influence on U5MR (under 5 mortality rate)

What is the effect of safe drinking water?

Mills-Reincke Phenomenon

‘…. the purification of polluted public water-supplies reduces the general death-rate much more than it would be reduced by the saving of deaths from the commonly recognized water-borne disease, typhoid fever and Asiatic cholera alone.’Sedgwick WT, MacNutt JS. On the Mills-Reincke phenomenon and Hazen's theorem concerning the decrease in mortality from diseases other than typhoid fever following the purification of public water-supplies. J.Infect.Dis. 1910; 7 : 489-564.

This is the “Environmental Engineers Saved the World” Hypothesis.

U.S. Typhoid Fever Mortality

Chlorination was begun in Jersey City, N.J., in 1908. Adoption by other cities and towns across the US soon followed and resulted in the virtual elimination of waterborne diseases such as cholera, typhoid, dysentery and hepatitis A

Chlorine saved the day

Chlorination begins in Jersey City

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http://www.americanchemistry.com/s_chlorine/sec_content.asp?CID=1133&DID=4491&CTYPEID=109

Chlorine Cause and Effect:What else would you like to know…

What was the mortality rate before the introduction of chlorine?

When did other cities adopt chlorination?How did the mortality rate change for cities

when they began chlorinating?What other changes were occurring during

the 1900s that may have influenced mortality?

Disease rates as measures of efficiency

“The final criterion of the efficiency of a purification plant is the absence or prevalence in the community of water-borne diseases. Typhoid fever being the most typical and widespread of such diseases, statistics of its prevalence are of much significance. Prior to the general introduction of purification works, the typhoid death rate was invariably high in many of our large cities drawing their supply from polluted rivers and lakes. Most of these cities are now supplied with satisfactory water, and many records could be given showing the marked effect of water treatment on the typhoid rate. The following data for the cities of New Orleans, Pittsburgh and Cincinnati will suffice.”

Public Water-Supplies by Turneaure, Russell, Mead, Baker. John Wiley & Sons (1924) pages 430-431.

Evidence for a Causal Link:New Orleans, Pittsburgh, Cincinnati

Pittsburgh, Cincinnati and New Orleans were used as evidence of the efficacy of filtrationPublic Water-Supplies by Turneaure, Russell, Mead, Baker. John Wiley & Sons (1924)

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New Orleans, LA

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Cincinatti, OH

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Pittsburg, PA

Let’s look at all the data using log scale (showing improvement ratio)

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Chicago, IL

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Cleveland, OH

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Detroit, MI

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Jersey City, NJ

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Louisville, KY

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Memphis, TN

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Milwaukee, WI

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New Orleans, LA

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Philadelphia, PA

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St. Louis, MO

Correlation between Water Supply Improvements and Public Health?

A causal link?FiltrationChlorination

Delayed response?No link?US 1900 – 1940

interpretation?

Chorine isn’t always required

The European Union does not require disinfection. Of the 15 original European Union member states, only Spain and Portugal require disinfection in distribution systems.1

1) http://www.epa.gov/ogwdw/disinfection/tcr/pdfs/issuepaper_effectiveness.pdf

http://www.epa.gov/ogwdw/disinfection/tcr/pdfs/issuepaper_effectiveness.pdf

Trying to Understand the Data

“The steady reduction… is probably due in part to improved operation and in part to the gradual elimination of the disease from the community and so removing sources of contamination.”

“It should be noted that typhoid fever is frequently traced to other causes than the water-supply,…”

What do you think?

Public Water-Supplies by Turneaure, Russell, Mead, Baker. John Wiley & Sons (1924)

Causes of diarrhoea according to ‘Diseases of children’

1889 1899

Sour milkUnripe fruitInhalation of sewer gasEmanations from the soil

‘no doubt that the immediate cause is an infection of the alimentary canal, by …bacteria contained in milk or other forms of food’

EmpowermentPowerlessness!

Changes recommended: public health campaign

Breast feedBoil cow’s milk, sterilize bottlesProtect infants from persons known to be illControl fliesWash hands

You can improve your health!

Reading the Typhoid Data

How long did it take for typhoid incidence to decrease? _____________

If typhoid was waterborne how long should it have taken for filtration and chlorination to eliminate typhoid? _____________

How does milk get typhoid?

30 to 40 years

A few weeks

Human excrement (milker’s hands?) or bovine excrement

My Typhoid Conclusions

The reduction was not due to a one time centralized changeNot due to filtrationNot due to chlorination

Was due to changes that occurred at different times throughout the population Improved hygiene

Installation of toilets in bathrooms with sinks to wash hands and toilet paper

Education encouraging hand washingBetter food handling practices

Milk pasteurizationRefrigeration

Public Health Education and medical care

Typhoid was likely not waterborne

Southwark Water Source

Courtesy of the National Library of Medicine

The Grand Cholera Experiment

Those houses served by the Lambeth Company had a low incidence of cholera, lower than the average population of London as a whole

Those served by the Southwark Company had a very high incidence

The socioeconomic conditions, climate, soil, and all other factors were identical for the populations served by the two companies

Snow concluded that the water supply was transmitting the cholera agent

Snow's study is impressive since the germ theory of disease had not yet been established

Proof that cholera was waterborne

1892 Cholera outbreak in Hamburg Germany

Large outbreak of Cholera in Hamburg 17,000 cases; 8,600 deaths Very few cases in neighborhoods served by Altona's

filtered water supply Hamburg's sewers were upstream from Altona's intake!

Altona's water intake and filter beds Hamburg's sewer outfalls

HamburgAltona

Elbe RiverHamburg's water intake

Altona vs. Hamburg: Cholera Cases

Hamburg

Altona

Cases in Altona acquired in HamburgCholera cases

Received water from Altona

Cholera was waterborne

Slow sand filtration may have protected Altona

Maybe we are helping to save the world from stunted growth

Of the 555 million preschool children in developing countries, 32% are stunted and 20% are underweight.1

A key cause of child undernutrition is a subclinical disorder of the small intestine known as tropical enteropathy

Caused by faecal bacteria ingested in large quantities

http://www.sciencedirect.com/science/article/pii/S0140673609609508

Fecal-Oral Pathways

Human excreta

Animal excreta

Dry sanitation involving reuse

Waterborne sewage

Non recycling latrines

Soil

Surface water

Ground water

Food

Drinking water

Oral

Pathogen source

Sanitation method

Land application

Environment Transport

Hands

Crops

Flies

Water

HygieneWater treatmentSanitation

washing

Improved or Safe?Improved

Came out of a pipe that was near the town.

Meets the Millennium Development Goal!!!!!!!!!!!

SafeWas treated to remove contamination and won’t make you sick

ImprovedSafeConvenient

ImprovedSafeConvenient

The customer wanted…Safe water on tap

What do people want?Reliable, easy access to plenty of safe, aesthetically

pleasing water Judge based on __________________________

Will they be willing to pay for and maintain more expensive infrastructure to have aesthetically pleasing water? ________________________We are competing with expensive bottled water and

cheap unsafe, inconvenient, unreliable water sourcesCan we make tap water as reliable as bottled water and

almost as cheap as dirty water?

looks and taste/smell

YES! (at least in many cases)

Course Reflections?

What is one thing that you learned in this course that you want to always remember?

Form groups of 3 and share your ideas.One minute to reflect3 minutes to share your ideas

Skepticism and Group Think

My default setting when reading a textbook or peer reviewed paper about drinking water treatment is to not believe the claims of the authors (remember typhoid)

Drinking water treatment is NOT a mature field

Every one of the core unit processes is poorly understood

Emerging Field of Sustainable Hydraulic Water Treatment

Conventional mechanical

Computer controlled peristaltic pumps

Sustainable hydraulic

Automated chemical dose controller

Chemical dosing

Rapid Mix• Velocity Gradient

various mixersNot sure how to scale

• Energy dissipation rateOrifice and jetKolmogorov length scale vs. clay separation distance



Velocity gradientResidence timeMechanical paddles


Energy dissipation rateCollision potentialBaffles

Flocculator

Sedimentation• 4 m deep

Mechanical sludge removalusually no floc blankettube or plate settlers

• 2 m deephydraulic sludge removalfloc blanketplate settlersawesome hydraulic controls



Rapid Sand FilterBackwash pumps


Stacked Rapid Sand FilterNo change in flow for backwash

Widely applicable: less costly and operate without electricity

We need to solve the clogging slot problem

Filter

Engineering for Love

Love is about helping others to thriveWe design water treatment plants so that

communities can thriveWe intend to make a world of difference!

Documents

Public Health Implications of Water Supply Improvements