As head mechanic, Ruch is charged with maintaining a fleet that includes
250 tankers, 35 of which are devoted to hauling soybean oil. It’s Ruch’s
job to make sure the tanker trucks are cleaned out thoroughly after
transporting material. Often, residual sludge must be removed from
15,000-pound stainless steel semi-tankers after hauling 48,000 pounds of consumergrade
soybean oil. After the crew washes the inside of the tanker, the
wastewater requires processing before it can be discharged to the City
of Mankato sewer system.
To help remedy this
situation, Ruch wanted an oil skimmer system that would more
efficiently remove unwanted oil before the wastewater was processed
through the facility’s dissolved air flotation (DAF) unit. He
purchased the company’s first skimmer from Oil Skimmers Inc., in
1999, has purchased two skimmers since then and plans to buy
another.
The heart of this oil skimming system is a polyurethane closed-loop
tube, which circulates on the water’s surface and attracts oil as it
floats, automatically adjusting to changing water levels. As the oil-covered tube passes
through scrapers to be cleaned of oil, it automatically returns to
the water’s surface to collect more oil. The recovered oil, which is virtually waterfree, flows into a collection
vessel.
The water-free recovered oil also has reduced Ruch’s disposal costs.
“The oil skimmers we presently own have saved us enough time and
money to more than pay for their cost,” he says, noting that
purchasing the oil skimmers has simplified his primary goal of
meeting municipal regulations for recycling wastewater.
“Knowing that we satisfy the municipality takes a big load off my
shoulders;’ Ruch says. “That fact alone makes purchasing the oil
skimmers one of our best long-term investments!
Previously, before installing the Model 5H oil
skimmer, a maintenance crew sprayed water mixed with a non-toxic
chemical into the trailers to clean out the residual oil. The
oilinfused water was collected in holding tanks, and the
crew then manually skimmed oil from the holding tank. The DAF unit
was used with a flocking agent to break up the remaining oil and
bring the residuals to the top of the water. The DAF unit then
removed the remaining sludge from the water.
“I appreciate that municipal guidelines for wastewater are strict,”
says Ruch. “However, it costs us money to bring our wastewater up to
standards for recycling back into the system. Add those costs to the
increased cost of fuel to run the tankers, plus the normal cost of
doing business, and I figured there had to be a better way.”
According to Ruch, the DAF unit works well, but is expensive to
operate and maintain. “Before purchasing the oil skimmer, we would
put in a lot of hours to manually skim the oil from holding tanks
before using the DAF unit,” Ruch says.
The oil skimmer has eliminated the process of manually collecting
sludge from the wastewater.
“Then we had to add a lot of flocking agent in
the DAF unit to break up the oil, which also raises the cost of
operation.”
The oil skimmer has eliminated the process of
manually collecting sludge from the wastewater. This allows the DAF
unit to refine the wastewater more efficiently, using a smaller
amount of chemicals.
“There’s little or no maintenance or upkeep
with the Model 5H because there are few moving parts,” Ruch notes.
“We can let it run day and night, and occasionally look to see that
the container holding the skimmed oil is not overflowing.’
The fully automatic Model 5H offers rugged
construction and few moving parts, which contributes to continuous
operation with minimal wear and tear. Ken Gray, Oil Skimmers sales
manager, western region, notes that in some cases, models purchased
more than 25 years ago are still operating today.
