Water & Air Quality for Indoor Aquatic Recreation Facilities Prepared by: Franceen Gonzales Great...
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Transcript of Water & Air Quality for Indoor Aquatic Recreation Facilities Prepared by: Franceen Gonzales Great...
Water & Air Quality for Indoor Aquatic Recreation Facilities
Prepared by:Franceen GonzalesGreat Wolf Resorts
Presented by:Presented by:Douglas C. SackettDouglas C. SackettAssistant DirectorAssistant Director
NYS Dept. Of HealthNYS Dept. Of HealthBureau of Community Environmental Bureau of Community Environmental
Health and Food ProtectionHealth and Food Protection
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
Water(H2O)
Air
Water exists in equilibrium
H2O ↔ OH- and H+
H H
O
H
O-
H+
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
Sodium Hypochlorite (NaOCl)Calcium Hypochlorite (CaOCl)
Chlorine Gas (Cl2)Bromine compounds
Water (H2O)
Air
Sanitizers have much in common
Periodic Table of the Elements
Chlorine plus water creates hypochlorous acid
NaOCl + H2O → HOCl + NaOH
Na
Cl
O
H H
O
Cl
H+
O
Na OH-
Substitution Reaction with Bleach (NaOCl)
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
BacteriaHOCl 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+ + OCl-
What pH does traditional pool chemistry target?
How do air and water interact?
H2O (water)HOCl (hypochlorous acid)
OCl- (hypochlorite)
Air
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)
H2O (water)HOCl (hypochlorous acid)
OCl- and Cl- (chlorine)
Chlorine salts
Chlorine off-gases into the air
Air
Chlorine and salts are deposited
Byproducts in air cause corrosion
Now let’s add people
Urine/ sweat
Hair productsLotions, etc.
OCl-
Chlorine Salts
Chloramines
Body fluids are the culprit
H2O HOCl OCl-
Plus other byproducts
Other disinfection byproducts
Trichloramine(NCl3)
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 CompoundsOrganic 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
NASA CR-1802, July 1971
Urea Predominates – 86%Urea Predominates – 86%Courtesy of Dr. Richard Cavestri
Urea
(NH2)2CO
C
H
N
O
H H
N
H
O
Urea + HOCl
C
H
N
O
H H
N
H
H
O
Cl
H
O
Cl
H
N
H H
N
H
ClCl
Urea + 2 Hypochlorous Acid = MonochloraminesUrea + 2 Hypochlorous Acid = Monochloramines
(Monochloramine is a disinfectant!)(Monochloramine is a disinfectant!)
CO2
H2O
Monochloramine + HOCl
O
HN
H
Cl
Monochloramine + Hypochlorous Acid = Dichloramine
Cl
H
ClN
H
Cl
H2O
Dichloramine + HOCl
O
ClN
H
Cl
Cl
H
ClN
Cl
ClH2O
Dichloramine + Hypochlorous Acid = 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?
Trichloramine
Cl
Cl
Cl
N
Trichloramine is volatile
• Mono- and di- chloramine like to stay in the pool
• Trichloramine likes to off-gasNCl3 = 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
ClCl
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 introduced from above
Chloramines, DBPs, water Chloramines, DBPs, water borne particulates are off-borne particulates are off-
gassing near water surface. gassing near water surface. Removing air at this level can Removing air at this level can
improve air quality.improve air quality.Worst air exhausted
Air Handling
ModelNorth
Drawing Layout Model Layout
ResultsTemperature
Relative Humidity
Mean Age
Temperature, RH, and LMA Plots
North
Plot viewed from the East
Plot viewed from the East
Plot viewed from the East
Results
1
Plot 1: 5 ft above floor Plot 2: 25 ft above floor Plot 3: 60 ft above floor
Mean Age
2
3
Water slides not shown
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