Wastewater Pathogens
What’s In There?
Steve Barnard
Muskegon County Wastewater
Management System
Afraid?
A little information goes a
long way…
Complex Issue
¾ Pathogen:
z
z
Bacteria
Viruses
Organism that causes disease
Bacteria
¾ Living
z
single cell organisms
Spherical (cocci),
Cylindrical (bacilli) and
Helical (spirilli); the spiral forms may be 15
microns long.
g
¾ Some
are pathogens
Bacteria
¾
Pathogen: Vibrio
Cholera; Disease:
Cholera;
Transmission: Person
to person;
¾
Pathogen: Salmonella
Typhi;
yp Disease:
Typhoid fever;
Transmission: Person
( animals)
(or
i l ) to person;
Bacteria
¾
Pathogen: Other types of
Salmonellae; Disease:
Various enteric fevers
(often called paratyphoid),
gastroenteritis,
septicemia (generalized
septicemia,
infection in which
organisms multiply in the
blood stream;
Transmission: Person (or
animals) to person;
¾
Pathogen:
g
Shigella
g
Dysenteriae; Disease:
Bacterial Dysentery;
Transmission: Person to
p
person
Bacteria
¾ Pathogen:
Escheiria Coli;
Disease: Diarrhea;
Transmission: Person to
person
Viruses
¾
Pathogen:
Poliovirus; Disease:
Poliomycetes;
Transmission:
Person to person
¾
Pathogen:
Coxsackievirus;
Disease: Various
cases including
respiratory disease,
fevers, rashes,
paralysis,
p
y , aseptic
p
meningitis,
myocarditis;
Transmission:
p
Person to person
Viruses
¾
H1N1 (Swine Flu) and
H5N1 (Bird Flu)
z
z
z
May be present in raw
wastewater. Readily
inactivated by disinfection
or digestion
Respiratory Illness, so
ingestion is not a method
of transmission.
Aerosolize as little as
possible
Aerosols
Viruses
¾ H5N1,
H5N1
z
z
z
H1N1
Does not survive outside body for extended
period of time
May survive through primary treatment, but
time is on your side.
Irrigation at our site
• 1980’s
980 s study
s udy showed
s o ed viruses
uses d
did
d not
o su
survive
e to
o
irrigation.
Viruses
¾ Hepatitis
z
z
z
z
A
Can cause severe liver damage
Spread fecal to oral
More common in developing countries
No documented cases of wastewater workers
contracting on the job.4
Viruses
¾ Hepatitis
z
z
z
z
B
B, C
Blood borne virus
Spread by direct contact with concentrated
blood or body fluids
Potentially fatal
One case of a worker infected by a needle
stick (bar screen)
Viruses
¾ HIV
z
z
z
z
Blood borne virus
Spread through direct contact with blood or
concentrated body fluids
Known since the 1980
1980’s
s
Does not survive outside the body
Chemical Exposures
¾ Gases
¾ Acids,
bases
¾ Organic
O
i Chemicals
Ch i l
¾ Metals
Gases
¾ Hydrogen
z
z
z
z
z
Sulfide
Toxic Gas!
Exposure limit 10 ppm (8 hr
hr.),
) 15 ppm STEL
Detectable at less than 100 ppb
Sense of smell quickly deadened
Local Ventilation
Gases
¾ Flammable
z
z
Gases
Accidental release from industry
Spills to sewer system
Organic Chemicals
¾ Vast
variety of possibilities
¾ Protective equipment and Engineering
Controls
¾ Regulation of discharges
¾ Know your customers
Acids / Bases
¾ Unlikely
to be present in concentration at
influent
¾ Release from industry to lift stations
¾ What you use around the plant is more
dangerous
dangerous
Metals
¾ Will
complex and bind in sludge
¾ Mercury is volatile and may be released in
aeration.
aeration
Exposure Routes
¾ Ingestion
z
z
(yuck)
Aerosols in the mouth
Swallowing
¾ Absorption
z
z
Through skin
Through cuts
¾ Injection
z
Forced directly into bloodstream
Will I get sick?
¾ It
It’ss
possible
possible, but unlikely
¾ Three things necessary for contracting a
disease
z
z
z
Pathogen
R t off entry
Route
t
Concentration
Concentration
¾ How
many organisms in how much water?
¾ How many organisms are required for
infection?
¾ Normal illness rates
¾ Pandemic rates
Is The Risk Really So Low?
¾ No
significant increase in human disease
appears to be attributable to aerosols from
wastewater treatment plants
plants, sludge
application, or spray irrigation sites. 1
¾ Questions remain
¾ Workers develop immunity, young workers
may have
h
lless resistance
i t
How Can Exposure Be Reduced?
¾ Engineering
z
Controls
Guards, baffles, covers
¾ Thoughtful
design (or modification)
¾ Personal Protective Equipment
¾ Industrial Pretreatment Program
¾ Hygiene!
yg e e
z
Momma told you to wash your hands
References
¾ 1:
Health Hazard Manual: Wastewater
Treatment Plant and Sewer Workers,
y 1997
Nellie J. Brown, Cornell University,
¾ 2: Safety and Health in Wastewater
Systems,
y
Water Environment Federation,
1994
¾ 3: www.all-about-wastewatertreatment.com/
¾ 4: www.cdc.gov
g
Wastewater Pathogens
g
What’s In There?
Steve Barnard
Muskegon County Wastewater
Management System
231 724
724.3441
3441
barnardst@co.muskegon.mi.us