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96 2019 INDUSTRY RESOURCE DIRECTORY Freezing: Protecting Your Units Rock Salt and Calcium Chloride Brine 1. Use a 200-gallon (approx.) tank for mixing. 2. Fill the tank with water. 3. Add 100 pounds crystal rock salt. 4. Add 100 pounds calcium chloride. 5. Mix well (an electric drill with a paint mixer works). 6. Pump mixture into truck using a small pump. 7. After filling the tank, run at least three (3) gallons of fresh water through the pump to be sure that all brine is washed out. This mix will be used when the temperature begins to average around 30˚F in the mornings. Increase the calcium chloride to 200 pounds (still to be used with 100 pounds of crystal rock salt) when the temperature begins to remain below freezing throughout the day. The timetable for cold weather servicing must, of course, be worked out according to temperature changes in your particular area. You will need to monitor this procedure carefully; your service technicians should let you know every few days how the mixture is working. Antifreeze An alternate method for winterizing units is the use of antifreeze. Before using antifreeze you must check with your local wastewater treatment facility to determine if they will accept it into their system. Use ethylene glycol, the main chemical in antifreeze on the market. When you seek the product to purchase, all you are looking for is the ethylene glycol, not the other additives that raise the price. Generally, two (2) ounces of deodorizer should be used with the antifreeze for the purpose of a slight mask. This may vary based on the product you are using. Check with your supplier to be sure. Below is a chart for percentage of antifreeze to use with water according to given temperatures. Numbers are based on a five (5) gallon charge. Contact your local health department before utilizing any winterizing mixture if you use a land application process of disposal. TEMPERATURE (˚F) % ANTIFREEZE WATER TOTAL 31–35 10 1/2 gal 4-1/2 gal 5 gal 26–30 15 3/4 gal 4-1/4 gal 5 gal 21–25 20 1 gal 4 gal 5 gal 16–20 25 1-1/4 gal 3-3/4 gal 5 gal 11–15 30 1-1/2 gal 3-1/2 gal 5 gal 5–10 35 1-3/4 gal 3-1/4 gal 5 gal Better worksites. Better weekends. Better world. EXCLUSIVE MEMBERS-ONLY CONTENT REDACTED Join us now at www.psai.org for access to this valuable information.