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Lifecore Biomedical Saves Over $69,000
Annually by Reducing Water and Sewer Costs
Evaluating Water Use to Decrease Cost
| Company |
Lifecore
Biomedical, Inc.
Chaska, Minnesota |
| Results |
Removing unnecessary
equipment and repairing water valves reduced water
use by 3.86 million gallons a year, saving $69,000
a year plus an anticipated $157,000 in one-time
SAC fees. |
| Cost |
$500
in supplies, $7,400 in flow meter rental fees, seven
hours of maintenance labor. |
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Lifecore Biomedical is a leading manufacturer
of dental implant systems, tissue regeneration products and
medical grade hyaluronan, a material with many uses in health
care. Lifecore manufactures medical grade hyaluronan (also
known as hyaluronic acid or sodium hyaluronate) using a fermentation
process that requires purified water, both as an ingredient
and for critical cleaning tasks. The Chaska plant used between
40,000 to 55,000 gallons of water per day.
Incentives for Change
A new family of products gained U.S. Food and Drug Administration
(FDA) approval in 2001. As Lifecore increases production,
the facility's water use will increase. Increased water use
will cost the company in price per gallon and in charges for
increased wastewater volume from both the Metropolitan Council
Environmental Services (MCES)—the metro area sewer authority—and
the City of Chaska.
MCES assesses a one-time Service Availability
Charge (SAC)* on increases in baseline water use in order
to fund expanded capacity in the sewer network. Because Lifecore
expected SAC charges to cost in the 100s of 1,000s of dollars,
the company requested a MnTAP intern to identify ways to reduce
water use and minimize the SAC fees.
The intern determined that the City of Chaska
had Basic Equivalent Unit (BEU) charges that were 2.5 times
higher than the SAC fees. BEUs are similar to SAC, but they
primarily support building infrastructure for distributing
freshwater. BEU charges are one-time costs.
Producing sterile, purified water at Lifecore
is expensive. It costs roughly 25 to 30 times the water and
sewer costs—as much as the SAC and BEU combined but on
a recurring basis.
* SAC unit = 274 gallons per day (gpd) of
sewered water.
Steam Generators
Pure-steam generators produce sterile steam from high purity
water for cleaning fermentation tanks and other production
equipment that comes in contact with the product. One generator
had a condensing coil to make steam sampling easier for quality
control. This coil used a 1.3 gallon-per-minute (gpm) continuous,
high purity water stream to condense a small, steam purge.
To lower the temperature before entering the polyvinyl chloride
(PVC) sewer line, a 1.0 gpm stream of city water was mixed
with the condensate wastewater. Lifecore wondered if the coil
could be removed from service because the second generator
operated without a condensing coil.
The intern found that quality control staff
had changed procedures and were taking samples at the steam's
points of use, making samples at the generators unnecessary.
Next, the intern investigated whether the coil's operating
parameters were embedded in the software programming of the
generator controls. Through the maintenance staff the intern
learned that the coil was manually adjusted
and could be removed without impacting how the generator operated.
The coil was removed in less than one hour for a total cost
of $20.
Cutting off the two continuous water streams
saved 1.2 million gallons per year (gpy) and cut utility costs
by $58,000 for high purity water and $1,800 for city water.
This reduction should reduce future SAC and BEU liabilities
by $49,000 at 2002 rates.
Autoclave
Two autoclaves were used to sterilize production equipment.
Both autoclaves were kept in standby mode when not in use,
where steam continued to warm the autoclave jacket and a continuous
flow of city water cooled the steam condensate. Standby mode
used 2.4 gpm of water on one autoclave and 3.6 gpm on the
second. The autoclaves were kept on standby rather than turned
off, in part for convenience and because previous experience
showed that thermal contraction and expansion during startup
and shut down led to increased maintenance for steam leaks.
The intern measured the temperature of wastewater at the drain during standby. Because the water temperature (56°F) was cooler than it needed to be for the PVC piping—rated to 150°F—the intern determined that the volume of cooling water could be reduced. Initial review of the plumbing and flow control system found three opportunities for improvement.
- A solenoid valve, that controlled flow to the aspirator used during the evacuation steps of the sterilizing cycle, leaked badly. The solenoid valve was repaired.
- One autoclave used a manually-set needle valve to control standby flow. A temperature regulating valve replaced the needle valve, cutting off the continuous cold water flow when it was not needed to reduce wastewater temperature.
- One autoclave using a newer temperature regulating valve was suspected of malfunctioning. The valve was repaired by replacing a missing orifice plug.
Repairs and modifications took about seven
hours of labor (cost $175) and cost about $500 in valves and
repair supplies. Wastewater flows during standby were reduced
to drips and trickles of less than 0.03 gpm each. Savings
were $8,600 per year in water and sewer fees, and possibly
$98,800 in avoided future SAC and BEU charges.
Evaporation Losses
The building air conditioning system included a cooling tower.
This cooling tower used an average of 2,000 gpd of water over
the six-month cooling season. The company did not know how
much of this evaporated and how much was sewered as blow-down
to control scale formation and the buildup of dissolved solids.
The intern examined the cooling tower's
control system, which was controlled by a flow meter on the
makeup water feedline. The water was purged from the system
to the sewer periodically. Using this information, the intern
determined how much makeup water was added between purges
and calculated evaporation rates.
The intern conservatively calculated 1.3
gallons of blow-down for every 47.1 gallons of makeup water.
MCES approved the calculations for evaporation rates based
on the number of purges recorded. While water use did not
change, excluding evaporation losses will cut Lifecore's sewer
bill. The company should save $870 a year in sewer fees and
may avoid $9,100 in future SAC charges.
Other Options
Lifecore was also considering proposals to:
- Add programmable controls to the fermentation process to reduce variability in water use between batches
- Optimize or eliminate condensate cooling
- Improve the steam yield from the steam generators
- Recycle off-spec high purity water to the feed side of the water purification system.
Application to Other
Companies
Measuring flow was critical to understand water use in Lifecore's
complex system. Because the company had numerous locations
that did not have permanent flow meters installed, it rented
two Panametric clamp-on flow meters that used an ultrasonic
signal to track flows over time. Rented at $7,400 for six
weeks, the meters were expensive but allowed the company to
easily monitor flows.
Consider including flow meters in the design
of new processes or when significantly modifying existing
processes. Turbine meters are much cheaper to purchase. They
are permanent and install as part of the pipe, tracking flow
by a turbine that spins as the flow
pushes past. Turbine meters require more effort to install
as a retrofit.
Rotometers are among the simplest, most
reliable and least expensive flow meters. The do not track
flow over time but provide visual feedback to operators on
flow level. Like other permanent meters, rotometers are more
difficult to install as retrofits.
The following clues helped Lifecore uncover opportunities to reduce its process water use. Look for them in your facility too.
- Similar equipment using different water volumes
- Visible flows that look larger than necessary or are present when they should not be (i.e., continuous flows when equipment is not running)
- Cool temperatures on drain lines from cooling applications. If you are trying to remove heat from a process, the used cooling water should be noticeably warmer after its use. A simple test is to feel if the outflow pipe is warm.
Impact at Lifecore
Water was reduced by 3.86 million gallons a year by removing
a condenser coil that was no longer needed and by repairing
water valves on two autoclaves. These changes reduced water
and sewer fees by $69,000 a year. As increased production
raises water use, the one-time SAC and city BEU charges are
expected to be $157,000 lower.
The changes cost $500 in supplies, $7,400
to rent two strap-on ultrasonic flow meters, seven hours of
maintenance labor and 500 hours of a student intern’s
labor to analyze a complex water distribution system and research
reduction options.
More Information
MnTAP has a variety of technical assistance services available to help Minnesota businesses implement industry-tailored solutions that maximize resource efficiency, prevent pollution, increase energy efficiency, and reduce costs.Our information resources are available online. Or,
call MnTAP at 612.624.1300 or 800.247.0015 from greater Minnesota
for personal assistance or more information about MnTAP’s
Intern Program.
This project was conducted in 2002 by MnTAP
intern Leslie Koesler, a chemical engineering senior at the
University of Minnesota.
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