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