Transcript Water & Air Quality Indoor Aquatic Facilities 3.27.2012 D. Sacket

Prepared by:
Franceen Gonzales
Great Wolf Resorts
Presented by:
Douglas C. Sackett
Assistant Director
NYS Dept. Of Health
Bureau of Community Environmental
Health and Food Protection
Water & Air Quality for Indoor
Aquatic Recreation Facilities
Issue
• A variety of health effects can occur
as a result of poor ventilation that
leads to accumulation of chemical
and biological products in the air.
Overview
• Indoor aquatic facilities are unique
• Water chemisty affects air quality
• Managing air quality through:
–Water chemistry
–Technological advances
–Air handling design
–Bather awareness
Indoor Aquatic Facilities are
Unique
• Controlled humidity and temperature
• Comfortable environment
• Restricted occupancy
• Air quality control is necessary
• 365 day operation is 3 outdoor seasons
of wear and tear
• Corrosion
Indoor Aquatic Facilities are varied
Water Chemistry Review
Air
Water
(H2O)
Water exists in equilibrium
H2O ↔ OH- and H+
H
H
H
H+
O
O-
Water molecules bond with other
water molecules
The average hydrogen bond lasts less than one trillionth of a second!
Now let’s add a sanitizer
Air
Sodium Hypochlorite (NaOCl)
Calcium Hypochlorite (CaOCl)
Chlorine Gas (Cl2)
Bromine compounds
Water (H2O)
Sanitizers have much in common
Periodic Table of the Elements
Chlorine plus water creates
hypochlorous acid
OH-
Na
Na
H
H
Cl
Cl
O
O
O
H
+
Substitution Reaction with Bleach (NaOCl)
NaOCl + H2O → HOCl + NaOH
Ions present in chlorine
compounds kill bacteria
• Cell walls of bacteria are negatively charged
• HOCl (hypochlorous acid) can penetrate
• OCl- (hypochlorite) is negative and cannot
penetrate as easily
HOCl
Bacteria
OCl-
How Chlorine Works to Disinfect
• Hypochlorous acid is more
powerful and exists at lower pH
• When pH rises, hypochlorite is
formed
HOCl + H2O → H3O+ + OClWhat pH does traditional pool
chemistry target?
How do air and water interact?
Air
H2O (water)
HOCl (hypochlorous acid)
OCl- (hypochlorite)
Water is hydrophilic
The average hydrogen bond lasts less than one trillionth of a second!
If it doesn’t have hydrogen,
then water doesn’t like it
H2O (water)
HOCl (hypochlorous acid)
OCl- (hypochlorite)
Chlorine off-gases into the air
OCl- and Cl(chlorine)
Air
Chlorine salts
H2O (water)
HOCl (hypochlorous acid)
Chlorine and salts are deposited
Byproducts in air cause corrosion
Now let’s add people
Body fluids are the culprit
OClChlorine Salts
Urine/
sweat
Hair products
Lotions, etc.
H 2O
HOCl
OClPlus other
byproducts
Trichloramine
(NCl3)
Chloramines
Other disinfection
byproducts
Did you pee in the pool?
1000 guests
Multiplied by % that pee in the pool
Multiplied by the avg volume a person
pees
Equals…..
Typical Organic Urine Compounds
Organic Compounds
Ammonium Salts
Creatinine
Taurine
Hippurate
Uropepsin
Cystine
Citrate
Creatine
Citrulline
Glucuronate
Glycine
Aminoisobutyric acid
Urate
Phenol
Threonine
Lactate
Histidine
Lysine
L-Glutamate
Androsterone
Incloxysulfuric acid
Asparate
1-Methylhistidine M-Hydroxyhippuric acid
Formate
Imidazole
Inositol
Pyruvate
Glucose
Urobilin
Oxalate
Asparagine
Tyrosine
Urea Predominates – 86%
NASA CR-1802, July 1971
Courtesy of Dr. Richard Cavestri
Urea
H
H
H
H
N
N
C
O
(NH2)2CO
Urea + HOCl
H
H
H
H
H
H
O
Cl
H
N
H
N
N
Cl
Cl
N
O
H
C
O
O
CO2
Cl
Urea
H
+
2 Hypochlorous Acid
H2O
= Monochloramines
(Monochloramine is a disinfectant!)
Monochloramine + HOCl
H2O
H
Cl
H
H
N
Cl
O
Cl
N
H
Cl
Monochloramine + Hypochlorous Acid = Dichloramine
Dichloramine + HOCl
H
Cl
Cl
Cl
Cl
N
N
O
Cl
H
Dichloramine + Hypochlorous Acid
Cl
H2O
= Trichloramine
Chloramine Formation from
Ammonia
Monochloramine
• NH3 + HOCl
→ NH2Cl + H2O
Dichloramine
• NH2Cl + HOCl → NHCl2 + H2O
Trichloramine
• NHCl2 + HOCl → NCl3 + H2O
(plus many other side reactions)
So what happens?
Cl
N
Cl
Cl
Trichloramine
Trichloramine is volatile
• Mono- and di- chloramine like to
stay in the pool
• Trichloramine likes to off-gas
NCl3 = trichloramine
• Trichloramine content in air
requires a specialized test
Typical Reaction to
Chloramine Exposure in Indoor
Swimming Pools
•
•
•
•
Irritated Eyes
Nasal and throat irritation
Coughing
Breathing difficulty
– Chest tightness
– Wheezing
– Congestion
Current Suggested Trichloramine
Thresholds in mg/m3
•
•
•
•
•
•
•
Levesque - .37
Massin - .5
Gagniere - .5
Hery - .5 - .7
Bernard - .3
Thickett - .5 (above threshold shows decrease in pulmonary function)
WHO provisional value 2006 - 0.5
Organochloramines Theory
• Cell wall of bacteria are proteins
• Hypochlorous acid kills bacteria, breaks it into smaller
pieces
• There are theories that chlorine could be randomly
attached to those small pieces of bacterial “carcass”
(proteins)
• Water chemistry shows combined chlorine to be much
higher when tested with DPD.
• These could be organochloramines (chlorine attached to
proteins of bacterial bodies)
• Larger organochloramines do not have the volatility of
nitrogen trichloride (TCA)
How do we control irritants?
• Water Quality
– Limit introduction of chlorine
– Secondary technology to break down combined chlorine
like UV, ozone
– Ultra filtration
• Air Handling
– Keep it clean
– Monitor temperature and humidity
– Push air high, remove it low
• People
– Public awareness
– Loading/occupancy
– Enforcement
Water Quality
• Maintain balance of free chlorine: not too much
in the air, not too much to create TCAs
– Keep it as close to 1.0 with effective pH and ORP
• Drop pH to achieve ORP for effective disinfection
– Ideal 7.2-7.4
• Ultra filtration addresses bacterial bodies
• Keep combined chlorine low
– Introduce fresh water every day
– Use secondary technology
Health department criteria for outdoor
pools is not always most conducive
to the quality of water and air in an
indoor environment
Indoor Pools are Unique
• Breakpoint chlorination is not always
feasible
– Cannot exhaust the off-gassing fast enough
• Pools recover at night
– Turn on features early to exhaust off-gassing
– Keep UV or ozone on
• Fresh air operation in the morning can
help
Secondary Technology - UV
• Low maintenance, less space required
• UV is effective at reducing chloramines, not
temperature sensitive
• Breakpoint chlorination not needed
• Disinfection is effective with exposure time
• Wavelengths 200-400 nm associated with
disinfection
UV breaks the bonds
of trichloramine
Cl
Cl
N
Cl
Cl
Other Technologies
• Ozone
– Effective oxidizer and disinfectant
– Requires extended contact time
– Equipment requires higher maintenance, more
space and is costly
• Monopersulfate
– Non-chlorine shock to oxidize contaminants
– Specialized test kit needed
Air Handling Principles
• 30 years of HVAC design for “dry” buildings doesn’t
work well for “wet” buildings
• Need to focus on the worst air
• Balance air exchange (fresh air and exhaust) with
energy efficiency (heat recovery)
• Selecting the right unit to move the air is as
important as designing the distribution and
controlling it
• It’s not a warehouse, it is a microcosm of weather
systems
• Body oils affect filtration
Air Handling
Air
introduced
from above
Worst air
exhausted
Chloramines, DBPs, water
borne particulates are offgassing near water surface.
Removing air at this level can
improve air quality.
Model
Drawing Layout
Model Layout
Temperature
Plot viewed from
the East
Results
Temperature, RH,
and LMA Plots
Relative Humidity
Plot viewed from
the East
Mean Age
Plot viewed from
the East
North
Water slides not shown
Results
Mean Age
3
2
1
Plot 1: 5 ft above floor
Plot 2: 25 ft above floor
Plot 3: 60 ft above floor
Air Flow
Paths
Animation
View from floor
indicated by red
arrow above.
Courtesy of TDMG
Air Handling Practices
• Keep the system clean
– Fans and blades
– Returns and ducts
– Filters
• Air, like pools, recover at night
– Keep UV or ozone operating at night
– Keep air handlers operating at night
• Set points for humidity and temperature can
be indicators of air quality but do not account
for contaminants
Address it at the Source
What They Need to Know
• TAKE A SHOWER BEFORE YOU ENTER THE
POOL and AFTER YOU LEAVE
• DO NOT PEE IN THE POOL
• DO NOT POOP IN THE POOL
What Operators Can Do
•
•
•
•
Provide guest awareness
Limit time in hot tubs, especially toddlers
Monitor occupancy in pools
Get parents to
– Take children to the bathroom
– Teach them not to pee in the pool
– Make them shower before they enter the pool
Guest
Education
Assisting Employees
•
•
•
•
•
•
Observe behavior
Keep an open door to sharing issues
Talk to employees
Experience it for yourself
Provide awareness
Offer alternatives
Critical Items
• Water chemistry
– Chlorine levels
– pH level
– Fresh water
• Correct ventilation scheme
– Volume
– Control
– Distribution
• Clean Bathers