Engine Cooling System Flush Water Disposal —
A Sensible, Safe and Affordable “Environmental-Business” Compromise
by IM Cool
Appeared in the September/December 2001 edition of
Recap: Unjustified environmental fear and regulations cause service shops to turn down cooling system flushes.
Proper procedures and enlightened agencies can bring back that much-needed service.
Suppose there was a man whose job for the past 31+
years has been to watch over folks who flush stuff into municipal sanitary sewer systems. During that time he certainly would have learned a lot about the makeup of those wastes, like which are detrimental to the sewage treatment process and which are not. Through constant analytical testing of in and outflows, he would also know which wastes (and how much of them) would actually produce a hazardous output from the sewage treatment process. Simply put, he would know what is safe for both the treatment plant, and the environment.
Now suppose that the hobbies of the person described above were automotive maintenance and restoration (particularly on Corvettes). What type of a person would you get? Easy, a Water Pollution Control Administrator who can minister a fair and accurate wastewater
discharge policy for automotive service shops. If your shop is in Hayward, California, you have such a public servant: Joe Lucia.
Joe understands the chemical products you use, why and how you use them, their cost and the cost of their disposal. Being a consumer, he is very conscious of the latter. That’s why, when the disposal of spent antifreeze became an environmental issue, Joe jumped in and made some important observations. Here’s his description of that process and outcome:
“Several years ago the City and other agencies conducted a sampling and analysis of the heavy metal concentrations of spent coolant as contained in the cooling system of vehicles at the time of system drain. Significant dissolved concentrations of several toxic heavy metals were found. These included copper, lead and zinc. Concentrations found significantly exceeded the end-of-pipe discharge standards for the City of Hayward as well as most other agencies. However, the analyses were of the concentrated cooling system drainage, NOT the “end-of-pipe” discharge from the shops (which is where the discharge standards apply). By capturing and recycling/off-hauling all of the spent coolant that can be practically performed, the remaining flushings should not cause an exceedance of end-of-pipe discharge standards for automotive service operations.”
What about the toxicity of Ethylene Glycol?
“The City has not performed analysis for Ethylene Glycol, per se, at the treatment plant inflow. However, ethylene glycol, while toxic at high concentration, is highly treatable at the concentrations received by a wastewater treatment plant. It is broken down by the biological processes just like all of the other organic compounds received for treatment. Of course, the discharge of “significant quantities” (hundreds of gallons) of relatively concentrated ethylene glycol could result in a toxic condition being created at our treatment plant. However, it’s highly unlikely that service shops will ever release such volumes.”
Description of the actual policy:
“The city allows automotive service facilities to discharge the flushings of automotive cooling systems into the sanitary sewer system PROVIDED that all coolant which can practically be drained from the system is first captured for recycling and/or off-site disposal. If all coolant is first drained and captured, the City deems the finish flushings to be in compliance with applicable sanitary sewer discharge regulations.”
City of Hayward’s procedures for coolant, and cooling system flushing, waste management:
1. There are no particular requirements or permitting required for the automotive service operation facilities. However, all flushings must discharge to an approved sanitary sewer fixture on the premises. This may be an INSIDE floor drain, a shop sink, etc. NO discharge to the storm sewer system (usually all drains external to a roofed building) is allowed under ANY circumstance. Such discharges are, by definition, illicit discharges and are a violation of federal law, which most cities are obligated to prohibit and enforce.
2. There is no restriction with respect to what type of vehicles may be serviced.
3. Preferred procedure: Flushing discharges are to be “free-flow” to the sanitary sewer system. Retention of flushing material in on-site tanks, with subsequent batch-type discharge, is not allowed without a special permit. Such a permit is not practical for an individual shop to apply for, or the city to issue.
Above: Joe Lucia, Water Pollution Control Administrator for Hayward, CA and an avid Corvette lover-maintainer. About the 1969 Corvette he’s owned since new, Joe says:
“It still has the original Harrison #3155316 aluminum radiator it was built with. I'm going to install a different engine so this radiator will be swapped for a Griffin aluminum replacement for the Harrison #3019190 copper/brass model. The original will be stored filled with a 65/35 mix of Prestone/water so as to keep it from drying out and corroding. Eventually it will be reinstalled along with the original engine.
I've driven this car for 200,000 miles, including through Death Valley in July two years ago. With ambient temps of around 115°F, the radiator kept the engine below 210° at all times. Under “normal” temp conditions the engine usually never runs above 180°, or so. Quite good performance for a 30 year old radiator, I'd say.”
Technician training required?
“No significant training required. The following simple points must be observed and communicated to shop personnel with oversight by shop owner/manager:
1) All coolant, which can be practically drained from the cooling system, must first be drained and captured for recycling and/or off-site disposal. This includes all coolant that can be drained from the radiator and from the engine. If possible, engine block and cooling line drains should be opened or removed to allow for drainage of coolant from cooling passages. The block drainage procedure is especially important for vehicles equipped with copper/brass radiators since these cooling systems contain higher concentrations of toxic heavy metal contaminants such as dissolved copper, lead, and zinc.
2) No concentrated coolant drainage may be discharged.
3) Flushing must be directed to a SANITARY SEWER SYSTEM drain. No flushings may be discharged to the surface and/or a stormwater collection system;
4) No other automotive fluids may be discharged to the sanitary sewer system without SPECIFIC approval from the City. As a practical matter, few, if any, other automotive fluids are acceptable for discharge to the sanitary sewer system.”
Why Hayward authorizes this type of discharge?
“The City recognizes that cooling system service operations are a necessary service that the public needs and requires. At the same time, we know that automotive cooling systems do contain significant amounts of certain toxic heavy metals, which are controlled/regulated by local ordinance and federal law. The longer that coolant remains in the cooling system, the higher the concentrations of these constituents are apt to be.
Above: Joe prides himself on keeping up with any and all of the latest information affecting his service facility. It was the plight of beleaguered auto service shops that prompted him to provide this plan for cooling system flushing relief. Joe knows our industry and which services are environmentally risky, and which are not.
We regard our approach as a BALANCED and CO-OPERATIVE effort between the City to address the problems in a mutually beneficial manner AND, most importantly, in a manner which addresses the significant environmental issues in an environmentally responsible way. We understand that it is practical to capture the majority of coolant contained in an automotive cooling system and recycle it on or off-site. Recycling is the ABSOLUTE BEST way to deal with concentrated spent coolant solutions. We also understand that it is not practical, or even possible, to capture ALL of the spent coolant and it is certainly not practical to capture the flushing water for off-site disposal.”
Chemical cleaners and cooling system flushing
“The City of Hayward has no specific restriction to the use or discharge of commercial chemical cleaners (acid or caustic-based) normally used during the flushing of engine cooling systems. The volume of such chemicals used is very low in comparison to the volume of water used to actually perform the flush.”
Specified volume of flush water?
“No particular amount of flushing water is required. However, we strongly encourage the use of sufficient water to thoroughly flush out the cooling system. This is entirely consistent with doing a PROFESSIONAL, thorough and proper cooling system service.”
More about wastewater and the public responsibility
“The primary problem with coolant discharges relates to the heavy metals which coolant extracts from the various components of automotive cooling systems and which is, consequently, present in significant concentrations in the spent coolant. Worse yet is the fact that these metals include primarily copper, lead, and zinc. Copper and lead are two metals which are very difficult for wastewater treatment plants to remove These metals are restricted by state and federal regulatory agencies from the effluent which treatment plants are allowed to discharge into receiving waters (bays, estuaries, rivers, lakes or the ocean). So, everyone has to do their part to reduce the discharge of these metals. By automotive cooling service facilities carefully observing the policy, we feel that the environment can be protected AND the legitimate needs of consumers and automotive service facilities can be accommodated. But, it’s VERY IMPORTANT that everyone does his or her part in a responsible way. Otherwise, a more restrictive discharge policy will be needed in the future.”
Show this article to your local wastewater treatment manager
It’s possible that not all wastewater treatment personnel have been able to gather the information about coolant and engine flushing as Joe. If your local water pollution control manager is not quite up to speed on this subject, Joe invites you to share this article to them. In fact, if they would like to contact him for more information, here’s how:
Joseph A. Lucia, Water Pollution Control Administrator, Hayward Department of Public Works, 3700 Enterprise Dr., Hayward, CA 94545.