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500 S. 4th Ave, Brighton CO 80601 Sand/Oil Separator Guidance Sand/oil Separators are below ground tanks designed to capture dirt, sand, sweepings, minor petroleum spills, etc. from vehicle maintenance facilities to keep these substances out of the wastewater system. The separator treats these wastes by allowing substances lighter than water (such as oil) to float and substances heavier than water (such as sand) to sink. Only the gray water between these two zones should flow to the wastewater system. Why is maintenance needed? If the sand/oil separators are not pumped frequently enough, the heavier dirt, sand, sweepings (sludge) and/or the lighter oil and grease will occupy too much space in the tank and be siphoned through the outlet pipe to the wastewater system. If the separator is not maintained property wastes can also cause a blockage and/or odor problems and public health issues. What are your responsibilities? Inspect and log your sand/oil separator inspections to assure that it is pumped as needed to keep prohibited wastes out of the City’s wastewater system. Refer to City of Brighton Municipal Code Chapter 13, article 12 for a list of prohibited discharges. Immediately following pumping, make sure the “tee” on the outlet pipe of the sand/oil separator is present, is properly secured to the wall, to make sure the tank is not just being bypassed. The primary purpose of the “tee” is to trap floating materials and keep them from exiting the tank. Sand/oil separator maintenance records must be kept on site for at least three years and available upon request. All cleanout of sand/oil separators must be performed by a contracted company. This company must be a reliable and trustworthy hauler authorized to pump out sand/oil separators and permitted to properly dispose of the waste. The contracted company will be responsible for the collection and analysis of oily liquid from the separator. Typically this involves using on-site qualitative procedures, and when those indicate that the tested materials may be classified as hazardous waste, a verification sample will be collected and a verification test shall be performed by an accredited laboratory. Avoid using any chemicals that have hazardous characteristics. ---PAGE BREAK--- When should the sand/oil separator be pumped? Sand/oil separators are required to be pumped frequently (at least every 4 months, unless a different pumping frequency has been allowed by the City inspector) to prevent the discharge of waste materials into the sanitary sewer system. The separator must be cleaned when the total accumulation of surface oil and settled solids reaches twenty-five percent (25%) of the sand-oil separator’s overall liquid depth. The chart below provides you with different vertical distances from the bottom of the outlet “tee” (same as water level), to the floor of the sand/oil separator. If the bottom of your outlet “tee” is 24 inches from the floor of the interceptor then, the bottom sludge layer or the floating materials layer shall not occupy a depth within six inches from the bottom of the “tee”. Sand/Oil Separator Maintenance Chart Water Level (inches) 24 36 42 48 54 60 66 72 inches Max capacity (top & bottom) 25% (inches) 6 9 10.5 12 13.5 15 16.5 18 inches The amount of waste in the sand/oil interceptor can be determined by using a tape measure or long rod. Remember: It could cost you more money in the long run to wait until the last minute to have your sand/oil separator pumped. Pump it regularly to avoid potential damage to your system, facilities, or Utilities Wastewater Collection System. Recommended Best Management Practices (BMPs) to reduce pumping frequency • Don’t wash spills into the sand/oil separator. Instead, use dry clean-up methods. • Wash vehicles and engines less often. • Filter solids out of the sand/oil separator using grates and screens over floor drains. • Use reusable absorbent pads that absorb only floating oil and grease. Once saturated, squeeze the oil into your used oil drum. • The use of any product that facilitates the bypass of the separator to the wastewater mainline is strictly prohibited. • Post signage near floor drains to remind employees to follow BMP’s. • Chemicals should not be stored or used near the sand/oil separator’s floor drains. • Contain leaks or spills if it can be done so safely, report any significant spill into the sanitary sewer to the City of Brighton Utilities Department. ---PAGE BREAK--- MAINTENANCE LOG FOR SAND/OIL SEPARATOR