SUB-PROBLEMS INCLUDING LEADING TO IMPAIRMENT AND BEST PRACTICES FOR HAZARDOUS WASTE TANK SYSTEMS
(See endnote 93)
Hazardous waste tank systems are typically used on site by the generators of the hazardous waste material. The hazardous waste tank systems and regulations cover not only the tanks but also all ancillary equipment including the leak detection system and secondary containment which includes a liner external to the tank, a vault, or a double-walled tank. There is a system to determine problems at small quantity generators of hazardous waste and large quantity generators, with each of them having their own requirements. The total discussion of each is beyond the scope of this book except for a general discussion on the design and installation of new tank systems which will be included under Best Practices.
Best Practices for Hazardous Waste Tank Systems
• Use the best available technology in designing the tanks and ancillary equipment for the specific types of hazardous materials to be stored and treated.
• Determine the potential for corrosion of tanks by measuring: soil moisture content and pH; soil sulfide levels; soil resistivity and structure; stray electrical currents and underground metal structures such as piping; and techniques used to prevent corrosion.
• Ensure that the tanks are anchored to foundations and that the foundations will be able to support a fully loaded tank.
• Describe and show the evaluation of any leak detection equipment and corrosion protection equipment.
• Describe and evaluate spill prevention or overfill equipment as well as secondary containment systems which must contain 100% of all waste materials in tanks, pipes, and equipment and has its own leak detection system and alarms.
• Use visual inspections on a daily basis to determine any cracks, imperfections in the protective coating, corrosion, etc. and make necessary corrections. Determine if everything is in good working order.
• For each existing tank system that does not have secondary containment, it must be determined by a qualified professional engineer that the system is designed properly, has adequate structural strength and compatibility with the wastes being stored and treated, and is not leaking. If the system is found to be leaking or unfit for use, it must be put out of operation and a new tank system installed which meets all current requirements including a secondary containment system with proper detection for spills and leaks and an alarm system.
• Underground tank system components must not be affected by vehicle traffic. The tanks have to be anchored to the tank foundation which has to maintain the load of a full tank plus anything within the lines or equipment. The system must be able to handle potential ground movement due to frost. Everything around this underground system has to be noncorrosive and not conduct electricity.
• All spills or leaks of wastes must be immediately neutralized and cleaned up.
• Frequently check all pumps, plumbing, piping, valves, and check valves as well as supports.
• Pressurized above-ground piping systems must have automatic shut-off devices if the system loses pressure and an alarm system to notify the operator.
• All underground systems must be established in such a way that ignitable or explosive vapors are not produced.
• Rainwater must be kept away from the systems for at least a 25-year period.
• Utilize all Best Practices for hazardous waste landfills.
• Receive appropriate certifications from the governmental operating authorities.
• Keep an accurate log of all inspections and events which have occurred.