Syd_water_09-25

Jeff Green | Jun 25, 2009

This meeting, held June 23, before the Committee of the Whole, was very sparsely attended by village residents. Cameron Smith of XCG Consultants presented a summary of the work done to date by his firm, in assessing the options for better removal of trihalomethanes (THMs) from the drinking water. He noted that Sydenham Lake has a relatively high amount of dissolved organic matter, probably because the lake is fed from wetland and bogs. The combination of chlorine and organic matter creates the THM by-products.

Testing indicated that the location of the water intake made no difference in the amount of organic matter present: various locations and depths showed no apparent variation in water quality.

After investigating a number of dis-infection methods, Smith said the one that seemed most effective and least costly appeared to be chloramination.

This involves reducing free chlorine contact time by adding a small amt of ammonia for secondary disinfection, which is long-lasting, and does not allow the formation of either THMs or HAAs (haloacetic acids) to build. UV would be used to inactivate Giardia & cryptosporidium. A further advantage of this process is the reduction of chlorine taste. However, the treated

water would be toxic to fish, and cannot be used in dialysis machines.

Chloramination is being used in a number of Ontario communities, including Toronto, Hamilton, Ottawa and Kitchener.

One resident questioned the effect on septic tanks: Smith responded that chlorine is quickly bound and neutralized by the organics in a septic tank, and should not present a problem. Another asked about reverse osmosis. The reply was that reverse osmosis is very expensive, requires lot of energy to operate, and is high maintenance.

Upgrades & modifications required to adapt the present plant to chloramination are expected to incur a Capital cost of $700,000 to $900,000 (two thirds of this cost should be covered by the Federal/provincial Build Canada grants) plus $5.000/year for the ammonia chemicals. There would be no change to the present plant's footprint.