Report to: General Committee Report Date: August 18, 2008

SUBJECT: Salt Water Pool Disinfection/Filtration

PREPARED BY: Colin Service, Manager Planning & Policy Development

RECOMMENDATION:

That the report entitled Salt Water Pool Disinfection/Filtration be received;

And that the Town of Markham staff continue to research alternative forms of pool sanitation with alternatives proposed in a subsequent report;

And further that Shore Tilbe Irwin and Partners be directed to incorporate liquid chlorine in the design of East Markham Community Centre;

And that Staff be authorized and directed to do all things necessary to give effect to this resolution.

1. Purpose 2. Background 3. Discussion 4. Financial

5. Others (Environmental, Accessibility, Engage 21st, Affected Units) 6. Attachment(s)

PURPOSE:

The purpose of this report is to respond to Council’s request to evaluate the effectiveness of utilizing salt water systems in Town of Markham pool operations.

BACKGROUND:

On October 9, 2007, Council directed staff to review the utilization of salt water sanitation systems as an alternative to chlorine to maintain the Town’s public swimming pools and report back.

It is necessary to and heavily legislated that the water quality in swimming pools and spas be physically and biologically clean. Both physical or mechanical and chemical cleaning must converge to create and maintain the high standard of cleanliness. The physical or mechanical cleaning of the pool water is accomplished by adequate circulation/filtration. The chemical cleaning is done through oxidation (chlorine.). Chloramines are a by-product of the initial sanitation from chemical cleaning. A secondary sanitation must then be used to address the creation of chloramines. Various chemicals can be added to the pool such as lithium hypochlorite, potassium monopersulfate or extremely high levels of chlorine. This is referred to as superchlorinations, breakpoints and shocks to the pool.

Cleanliness and Disinfection of Class A Pools

The Town of Markham Pools are all Class A Pools. According to Public Pools Regulation 565, the definition of a Class A pool is “A pool to which the general public is admitted”.

Requirements for disinfection of a Class A pool include that pool water be treated with chlorine or a chlorine compound by means of an adjustable dosing device and that the residual of free available chlorine is not less than 0.5 milligrams per litre in every part of the pool (Reference: Reg. 565.s.7.7.a.)

Fundamentals of Salt Water Chlorination

To create a salt water pool, salt is added to the pool to maintain 2,600-3,000 milligrams per litre of salt, a level similar to what is in tears. As a comparison, the salt level in the ocean is over 300,000 milligrams per litre. A Salt Water Chlorinator then produces its own chlorine when mildly salted water passes through a salt cell. The chlorine that is produced dissolves instantly in the pool water, maintaining the legal requirements for chlorine disinfection.

There is a very common perception that salt water pools are chlorine free pools. However, salt water pools operate with as much chlorine as do pools utilizing a liquid chlorination system. The main difference is that because the chlorine is produced and instantly dissolves in the pool water, the traditional smell of chlorine is not as strong.

OPTIONS/ DISCUSSION:

Currently the Town of Markham operates all pools with liquid chlorine as the primary method of disinfection. Below is a summary of the pros and cons of our existing system compared with a salt water system.

Table One - Existing Liquid Chlorine

Pros

- Existing system has proven to be functionally effective, safe and simple to operate - Liquid chlorine is pumped in from outside eliminating the need for staff contact - All Town of Markham pool operators are trained in the operation of existing systems - Capable of maintaining water clarity for high bather loads - Fluctuating bather loads are easily accommodated - There is no new capital costs associated with continuing use of existing system

Cons

- Skin may become irritated if bathers have a chlorine sensitivity or allergy - There is a strong smell that is associated with liquid chlorine use in public pools, particularly indoor public pools

Table Two: Salt Water Chlorinator

Pros

- Water feels “softer” due to the increase of Total Dissolved Solids in the water - Customers may be more comfortable in water with less skin irritation - Chlorine generated is not handled by staff – enclosed cells, safe to operate - Chemical savings as you are generating chlorine

Cons

- Skin may become itchy if bathers do not shower within a half hour of exiting water - No additional protection from chlorine resistant parasites - System is not common throughout Ontario – more difficult to find qualified companies for maintenance and repair service - Costly to install and maintain for minimal benefits - Corrosive on metals such as heat exchangers, pumps, mechanical equipment, copings of pools and building envelope - Skin may become irritated if bathers have a chlorine sensitivity or allergy - Waste water may pose an environmental hazard such as damage to downstream agricultural and aquatic uses due to the chloride content. - Slow to react to high demand bather loads - Increased total dissolved solids (TDS) may result in staining of the bottom of pool, water inlets, etc.

FINANCIAL CONSIDERATIONS AND TEMPLATE:

Based on consultation with Water & Ice North America LTD and SP&S Pools, the following capital costs were identified in consideration of pool size, flow rates of each pool and other pool operating parameters.

The estimated annual costs were based on the maintenance contract estimate as provided by Water & Ice North America LTD and in consultation with SP&S Pools. The annual maintenance costs using the current disinfection method for the pools at the seven facilities is approximately $3,000.

Disinfection Method	Capital Costs to Install	Estimated Annual Maintenance Costs
	( - ) Number of pools per facility	(per Facility)
Salt Water Chlorinator	Angus Glen (3) $ 86,000	Angus Glen $10,000
	Centennial (4) $108,000	Centennial $12,000
	Milliken Mills (3) $ 86,000	Milliken Mills $10,000
	Thornlea (1) $ 35,000	Thornlea $ 3,500
	Thornhill (3) $ 73,000	Thornhill $ 6,500
	Morgan (2) $ 57,000	Morgan $ 2,000
	Rouge River (1) $ 35,000	Rouge River $ 1,200
	SUB-TOTAL $480,000	TOTAL $45,000
	10% Engineering $ 48,000
	TOTAL $528,000

ENVIRONMENTAL CONSIDERATIONS:

While some consider salt water pools to be a more environmentally friendly way to run pools, the opposite may in fact be true. On a daily basis, the Town of Markham drains 30,000 to 40,000 gallons of water from public pools to allow for make-up water to be added. In a salt water pool, the waste water would have a residual of 2,600-3,000 milligrams per litre of salt. Salt dissolved in water forms sodium and chloride. Chlorides are not healthy for the environment. A district in California recently banned all pools with a salt water level of 2,000 milligrams per litre or higher from connecting to the area’s sewer system in order to protect downstream agricultural and aquatic uses as the sewage plant can not remove chlorides from the water.

Salt water pools have also been found to be corrosive on the building envelope, the mechanical equipment and metal components. It can affect concrete copings and leaves salt residue everywhere.

RECOMMENDED

BY: ________________________ ________________________

Barbara M. Roth Brenda Librecz

Director of Recreation Services Commissioner,

Community & Fire Services

ATTACHMENTS:

Appendix 1 – Electrolytic Chlorine Generators

Appendix 2 – Powerpoint Presentation on Salt Water Pools

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