| Source
newsletter winter 2002 |
|
 |
Optimizing Your Curds and Whey
A Minnesota
dairy ran CIPs after producing its curds and whey. Along came
an intern who worked along with them helping to make reducing
waste pay.
Having
a computer control cleaning production equipment, one Minnesota
dairy eliminated most of the waste caused by day-to-day inconsistencies
from cleaning.
The dairy
facility produces cream, cheese, lactose products and protein
concentrates. Most of its clean-in-place (CIP) systems—which
eliminate the need to dismantle equipment in order to clean
and sanitize—are centrally controlled and monitored by
a computer that runs pumps and valves and designates time,
temperature and conductivity requirements.
But, in
1999, the company was overloading its water pretreatment plant—both
with water volume and biochemical oxygen demand (BOD). The
dairy speculated that the flushes and rinses of its CIP systems
were too long, contributing to the problem.
"We
had gotten a number of new CIP systems and we were more concerned
about getting them up and running, and running properly, than
the extra water each of them was using," said the whey-side
manager. "When we read about the intern program, we said
this is something an intern can take care of."
The dairy
had MnTAP intern Zachery Perry, a chemical engineering
student, review its CIP systems and adjust the duration of
the water flushes and rinses. The intern also investigated
ways to reduce BOD loading.
"He
was one of the best interns I've ever had," said the
whey-side manager. "When my management asked me to supervise
him my first comment was I don't have time for a baby-sitting
job. But, I spent one day with him and let him go."
Reducing
Rinse Water
The CIP process generally consists of rinses, which go to
the drain, and acid and caustic washes, which return to the
tanks for reuse. The intern optimized CIP rinse times. Overall,
pre and post rinses were shortened slightly and wash rinses
between solutions were shortened substantially.
Decreasing
BOD Loading
CIP procedures often contributed significantly to the dairy's
BOD loading, especially during cleanup at the end of a day's
run when a line's left over product was washed down the drain.
Most of
the solutions were adjustments to operating procedures. By
requiring operators to flush systems before they were routed
to the drain at the end of the day, only five to six percent
solid waste exited the machine instead of 20 percent.
Overall
Results
With the MnTAP intern's help, the dairy decreased its water
use by 8.5 million gallons annually, saving over $20,000.
It also decreased its BOD loading by 2.5 percent, saving over
$6,000 per year.
By fine
tuning its system, the company reduced waste effectively without
overhauling its current technology. The company has since
expanded.
|
