Consideration and Approval of Proprietary Purchase:  Purchase of Saf-T-Chlor dry sodium chlorite and drums from CDG Environmental, LLC.

The Water Services Water Production Section uses a chlorine dioxide generator for surface water pretreatment, or pre-oxidation, at the Lake Mary Water Treatment Plant. The current chlorine dioxide generator at Lake Mary was installed by CDG Environmental, LLC in 2008. It requires the use of the proprietary chemical Saf-T-Chlor dry sodium chlorite requested in this purchase.

Using the chlorine dioxide generator as a pretreatment method works well for treating metals such as iron and manganese and as a disinfectant for bacteria, protozoa and algae and taste and odor compounds without creating disinfectant by-products (DBPs).  With the increase in Lake Mary water levels, it is anticipated that more surface water will be utilized this year.  It is necessary to purchase the Saf-T-Chlor dry premium chlorite and accompanying drums in order to maintain the current treatment process and maximize the use of surface water from Lake Mary.

Water Production annually budgets for chemical expenditures under account 202-08-301-1011-0-4362 (Lake Mary Water Treatment Plant (Chemicals)) to cover the costs associated with chemicals used at the Lake Mary Water Treatment Plant.

This expenditure assists Water Production in meeting Safe Drinking Water regulations pertaining to disinfection by-products.

Flagstaff Regional Plan, Goal WR.4:  Logically enhance and extend the City's public water, wastewater, and reclaimed water services including their treatment, distribution, and collection systems in both urbanized and newly developed areas of the City to provide efficient delivery of services.  Policy WR.4.2:  Maintain, at the City level, a financially stable utility to provide reliable, high-quality utility services.

This will be the first time Water Production has sought purchasing approval of sodium chlorite drums from CDG Environmental, LLC over $50,000 (fifty thousand dollars).

1. Approve the purchase of Saf-T-Chlor dry sodium chlorite and drums from CDG Environmental, LLC to be used with the onsite chlorine dioxide generator at the Lake Mary Water Treatment Plant for surface water production; or
2. Reject the purchase of Saf-T-Chlor dry sodium chlorite and drums from CDG Environmental, LLC and leave Water Production with the options of either finding another chlorine dioxide or other pre-treatment/pre-oxidation system to use or return to using chlorine for raw water pre-oxidation or pre-treatment.

In 2008, the Lake Mary Water Treatment Plant upgraded the treatment process or added an onsite chlorine dioxide generator to be able to apply chlorine dioxide to raw water.  CDG Environmental, LLC was chosen as the supplier of the equipment which utilizes Saf-T-Chlor, a proprietary dry form of sodium chlorite that is used to make the chlorine dioxide on-site.  The use of chlorine dioxide as a pre-treatment for surface water helps oxidize iron and manganese, reduce taste and odor, disinfect any bacteria, parasites or algae in the water; without creating disinfectant by-products (DBPs).  In 2015, Water Production increased the use of chlorine dioxide to help reduce DBPs.  Now in 2019, the City plans on increasing the amount of surface water processed to maximize the benefits of using surface water.  Past sodium chlorite purchases were always below the annual thresholds, however, with increased usage compounded with an increase in surface water production, expenditures for the sodium chlorite require Council approval.

As required under the Procurement Code, the information regarding the proprietary status of the Saf-T-Chlor dry sodium chlorite and drums from CDG Environmental, LLC was provided to Purchasing. One of the factors considered was the safety protection with the purchase of proprietary steel drums that are completely sealed preventing against splash, spills or leaks that may harm employees. Purchasing determined that this proprietary purchase was acceptable.

The use of chlorine dioxide as a raw water oxidant has been shown to minimize disinfectant by-product formation in the City of Flagstaff's drinking water.

The use of chlorine dioxide is roughly 14 times as expensive as using chlorine, however, the benefits outweigh the costs, specifically with reduced disinfection by-product (DBP) formation.

Allowing the expenditure of up to $100,000 (one hundred thousand dollars) annually on Saf-T-Chlor dry sodium chlorite and drums from CDG Environmental, LLC will enable Water Production to take advantage of the abundant water in Upper Lake Mary in 2019 while keeping disinfectant by-products under maximum contaminant levels (mcl's).

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