PROTECTION OF STORM DRAINS FROM OIL AT AUTOMOTIVE AGENCY
CASE STUDY N°.: 1
In the Capital Regional District of Greater Victoria on Vancouver Island, British Columbia, a bylaw has been enacted requiring companies who discharge wastewater into storm and sewer drains to restrict the Hydrocarbon oil levels to 15 parts per million (PPM).
With co-operation of a major car agency in Victoria, an extended trial was carried out to develop a containment system for several storm drains and sumps which discharge wastewater into the city storm drains.
The work involved several of the products using the MLM Technology including Basket Filters, Floor Drain Petro Barriers, Petropads, and SDB-OG (oil water separator).
Using this combination of different products, together with recommendations in the use of cleaning fluids, the auto company was awarded a Certificate of Compliance with the Bylaw by reducing the oil contamination in the discharge water from 240 – 500 PPM.
Another automotive agency has subsequently been approved using the Petro Barrier products and several more have agreed to use the technology and obtain certification.
A copy of the Certificate of Compliance issued to the auto agency is shown below:
Protection of Storm Drains in Automotive Agency
The Capital Region District of Greater Victoria, British Columbia, enacted a bylaw and a code of practice in 2004 requiring that automotive workshops restrict the levels of hydrocarbon oils and greases to 15 mg/l (15ppm) or less in the waste waters exiting from their place of business into the storm drainage system.
In many cases, businesses opted to seal off their drains from the local authority storm drains becoming “dry shops”.
In the case of one major car agency, with three workshops, this was particularly difficult because of the number of drains on their property which exited to the storm drains of the city of Victoria.
In particular, there were three major drains that collected water from a large car washing operation and an oil-water separator dealing with effluent from the detailing shop.
In all three cases, not only were these drains collecting water contaminated with visible oil, but there were significant amounts of grit and sludge being washed into them.
Initial random sampling of the water flowing into the city storm drain showed oil levels ranging up to 500 mg/l on occasions and the solids accumulation necessitated pumping out on a regular basis. The high levels of oil came from both the car washing operation (as many as 90 vehicles /day) and also from the oil-water separator which dealt with all waste water from the workshops, and in particular the detailing operation.
Petro Barrier Systems Inc. (PBSI), a small environmental company with patented technology and products for the containment of hydrocarbon oils to prevent contamination of storm water systems, together with Safechem Systems (SCS), involved with the marketing of this technology, approached the car agency with a proposal to protect the drains from oil contamination.
Initially, absorbent Petro pads were installed in all the California drains and sumps in the inside workshops. These absorbed and filtered any oil spills and prevented any contamination from exiting the work area.
In one instance, up to 3 gallons of transmission oil was inadvertently spilled into a sump containing a floating Petro Pad. This pad was able to absorb nearly 80% of this spill and the remaining oil was removed by spreading loose granular absorbent on the surface of the water to suck up the oil in 10 – 15 minutes. The absorbent reacts with the oil and eventually becomes a rubbery solid which does not leach from the solid. The previous solution was to remove all the oil and water with a vacuum pump and take the oily water to an approved treatment site for disposal.
For the three outside drains, proprietary designed equipment was installed to contain both the grit/sludge and the oils while allowing the water to exit from the property into the storm drains.
Drain – Car Wash
This drain took all water, oil and sludge from the area where all the cars were washed. It flowed into a second drain lower down the property and then into the city storm drain.
A mini-3-compartment oil and grit/water separator MLM-SDB-OG occupying some 50% of the space was installed in this drain. Provided that the grit build up was cleaned on a regular basis, the liquid exiting from the SDB-OG appeared reasonably clear with little evidence of sludge and sheen.
Drain – Mid-Yard
This drain received water from the above drain and rainwater and wash water from the pre-wash of cars prior to full wash treatment. It was also subject to any oil sheen from the car line up. The most serious source of oil contamination came from a pick-up truck, which housed old engines awaiting disposal. This resulted in significant volumes of sheen passing into this drain.
The water exiting from the drains to the storm drain does so by a siphoning action through a T-piece in the drains. This results in a level of water in the drain at all times.
The devices installed in this drain comprised a basket filter, MLM-SDBF, with absorbent Petro Pads and a storm drain barrier –MLM-SDB-OG. The basket filter is designed and installed in the drain to filter out oily sheen and also to contain any major oil contamination thereby preventing oil from entering the storm drain. The storm drain barrier – MLM-SDB-OG- is installed inside the basket filter to pre-screen any grit and sludge and act as an oil-water separator. An additional pre-screen of filter material is installed just under the drain grating to deal with larger sized grit. The protection is complete with a Petro Pad floating on the surface of the water inside the drain.
Round drain – Lower Yard
This drain received rain run off (with sheen) from an area outside the oil storage facilities and also the water from the oil-water separator.
The oil storage area was particularly concerning because tankers transferred oils into holding tanks on a regular basis and drips and spills onto the asphalt yard were common.
The protective devices installed into this drain were identical to the square drain in the mid yard; i.e. a basket filter with Petro pads, an MLM-SDB-OG, pre screens for coarse grit and Petro Pads floating on the water.
After some preliminary problems with the operation of the MLM-SDB-OG, the water flow through the systems was more than adequate to deal with the volumes of water both from the car washing operations and also the normal rainfall.
(The MLM-SDB-OG is designed to operate on a by-pass system in the event of rainfalls greatly in excess of the norm or if the compartments become blocked for any reasons.)
The water exiting from the square mid and lower round drains was sampled and tested for total extractable hydrocarbons. The results were totally unacceptable, ranging from 200 – 450 mg/litre. Further examination of this contaminated water showed that the oil was “solubilised” in the water and could not be removed with the absorbent.
A review of the workshop operations and the car washing demonstrated that the use of detergent liquids was standard practice and it was quickly concluded that, with the existing methods of cleaning cars and automotive parts, it was unlikely that the water would ever achieve the desired target levels of oil going into the storm drains, mainly because of the solubilising effect of the detergents on the oils.
At this time, SCS, had acquired a water based cleaning fluid which was shown to be very effective in removing oils and dirt without causing any solubilising or emulsifying of the oil with water; i.e. the oil remained a discrete separate layer on the water surface.
The automotive company was approached to review the liquids used in the different cleaning operations and replace them with this water based cleaner. It was quickly demonstrated that the cleaner could in fact replace all of these different detergents and solvent cleaning liquids without any reduction in performance.
After several weeks with the replacement cleaner, the water exiting the drains was tested again and results of 5 – 10 mg/l were obtained.
The environmental officials of both the city of Victoria and the Capital Region District have now inspected the facilities, reviewed the technology and evaluated the levels of oil in the water entering the storm drains. A certificate has been issued to the automotive company indicating their compliance with the by-law requirements.
The municipal authorities do not endorse any specific technology but acknowledge the effectiveness of the technological approach based on acceptable oil levels as shown in test results.
A major conclusion, which has come out of this project, where significant quantities of grit and sludge are being washed into the drains, is the need for regular servicing of the installations to ensure the maximum efficiency of operation. Assuming regular servicing is carried out, this project has shown that storm drains can be effectively protected from oil contamination, both “sheen” and major spills
It should also be stressed that the MLM technology for oil spills does not prevent spills from occurring. Rather the technology provides a means of containing oil spills and protects water systems from major contamination of the drains.
The MLM technology is an insurance policy against potential spills, which could result in significant legal action and financial sanctions by regulatory authorities.
The MLM Technology
The Muir Lock Monster (MLM) technology for the containment of hydrocarbon oils and greases developed over the last 3 years has recently been awarded a patent by the US Patent and Trade Mark Office and also has preliminary acceptance for protection in more than 100 countries world-wide through the Patent Co-operation Treaty based in Geneva, Switzerland.
This project would not have been successful without the co-operation and dedication of both PBSI and SCS, and the management and employees of the automotive agency to achieve compliance with the regulations.
THREE STAGE OIL WATER SEPARATOR IN DRAIN OF AUTOMOTIVE CAR DEALERSHIP IN OPERATION
OIL AND SLUDGE WASHED INTO DRAIN AND PASSES INTO COMPARTMENT #1 WHERE IT SETTLES THEN WATER AND LESS OIL AND SLUDGE PASS INTO COMPARTMENT #2
OIL AND SLUDGE ARE ALLOWED TO SETTLE IN THIS COMPARTMENT AND WATER, RELATIVELY FREE OF OIL AND SLUDGE PASS INTO COMPARTMENT #3.
FINALLY OIL AND SLUDGE FREE WATER EXITS FROM #3 THROUGH THE OUTLET PIPE TO A SECOND DRAIN AND THEN TO THE CITY STORM DRAIN SYSTEM.
THE WATER IN #3 SHOWS NO EVIDENCE OF SLUDGE AND OIL SHEEN.