 |
| Most
parts manufactured at Metal Seal and Products are anodized.
The random loading style automated line runs virtually non-stop
at the facility, where brake parts, medical and electronic
parts are manufactured.
|
"The county
was sure that our water meter was faulty. They tried to arrange
for us to shut down so they could come in and take the meter apart
and inspect it," stated Dale Diemer, environment, safety and
health manager for Metal Seal and Products, Inc. (Willoughby, OH).
The county had trouble believing that the company's water savings
could be due to the new water recycling and wastewater system it
installed for use with its anodizing, zinc plating and passivation
processes. Eventually, Mr. Diemer convinced the county that the
water savings was due to the new system, and the shutdown was avoided.
According to
Gordon Diemer, plant manager and cousin of Dale, the whole system
came about because the company was spending a "small fortune"
on water and waste treatment. "We were also having a lot of
plating problems, where we were probably reworking 12-15% of what
we made," noted Mr. Diemer.
Major customers
for Metal Seal include the automotive, plumbing and electronics
industry, with automotive making up the majority of the work. Metal
Seal handles all parts from start to finish. It receives the raw
steel and aluminum and uses CNC machinery, drills, tappers, spindle
and screw machines, among others to form the metals into parts.
Parts for the automotive industry include mostly brake pistons for
anti-lock brake systems, ABS components and other automotive and
truck brake components.
Most of these
parts are passivated, zinc plated or anodized. The zinc plating
line was replaced a year and a half ago in order to increase capacity.
The old line could handle approximately 60,000 pieces per day. The
new line tripled the capacity of the previous line. However, the
new installation was not without problems. Gordon Diemer tells of
a frustrating, but now somewhat amusing story of what happened in
one of the zinc plating tanks. "After we put in the new zinc
line, one of our zinc plating baths went bad. We were getting terrible
plating. We sent out a bath sample to Atotech for analysis, and
it came back with formaldehyde in it. That was odd, and we did not
know where it was coming from until we realized that someone had
left the overhead door in the back open too long and some leaves
had blown into the tank. When the leaves break down, they create
formaldehyde. We had to dump an 8,000 gal tank, scrub it, passivate
it, hose it out and make it up all over again. Not to mention the
debris we found in the tank from the guys working on the roof putting
in a new air duct: PVC, a screwdriver, fiberglass and a steak knife.
I would not want to go through that again."
The zinc line
is automated with five rack stations and one barrel station. Parts
are manually loaded and then a PLC reads the bar code to determine
the plating sequence for the parts.
The new water
recycling and waste treatment system from Kinetico
Inc. has helped tremendously on the zinc plating line. Not only
are the rinses and baths cleaner, but also the blue bright, yellow
and olive drab chromates adhere better to the parts. The olive drab
is a special color that Metal Seal runs only for Ford. Ford wants
everything under the hood of the truck to be silver or black, however
this one part cannot be made black, and Ford does not want it silver.
The dark olive drab is the best option. "It is a difficult
bath to maintain," noted Mr. Diemer. "We only run about
10,000 pieces a year in this color. It is finicky, with a tight
pH and concentration range."
All finishing
baths are titrated daily using an auto-titrator. Metal Seal also
does routine split sampling of the baths, sending samples to Atotech
and an independent laboratory for analysis.
Most of the
parts at Metal Seal, however, are anodized. Recently, Metal Seal
installed its third anodizing line, having outgrown the previous
two. The new line, from Abfintech, is random loading and runs nearly
nonstop, anodizing between 80,000 and 120,000 pieces a day of mostly
6061 aluminum and its alloys. Both Type II and Type III anodizing
are done on the 43-station line where parts can be also be dyed
purple, red, gold, brown, green and blue. Parts are dyed for identification
purposes only, since all the parts Metal Seal manufactures are functional
in nature.
| TABLE
I-Chemical Design Specifications
|
Solution Temperature, maximum
pH (range)
TDS (total dissolved solids), maximum
TSS (total suspended solids), maximum
Conductivity
TOC (total organic carbons), maximum
Oils and Grease, maximum
Cyanide
Copper
Nickel
Lead
Chromate
Zinc |
Influent
120F
2-12
500 mg/liter
25 mg/liter
1,000 micromhos
25 mg/liter
5 mg/liter
0 mg/liter
<50 mg/liter
<50 mg/liter
<10 mg/liter
<10 mg/liter
<50 mg/liter
|
Effluent
120F
6-8
10 mg/liter
2 mg/liter
20 micromhos
<5 mg/liter
<1mg/liter
<1mg/liter
<1mg/liter
<1mg/liter
<1mg/liter
<1mg/liter |
The Kinetico
system again helped with the anodizing line by not only keeping
the rinses clean and cleaning up the baths through turnovers, but
the dyes now adhere much better. "Our reject rate has gone
from 12-15% down to 1-2%," commented Mr. Diemer. "I attribute
it all to the water softener we put in that removes calcium and
magnesium. By filtering out the magnesium and calcium, we were able
to use sulfuric acid instead of hydrochloric acid in the treatment
system. Sulfuric acid is less expensive. Because our baths and rinses
are so clean, we save about $2,000 to 4,000 a month in chemical
costs."
In addition
to reducing reject rates, the water softener, in conjunction with
the wastewater treatment system, has helped Metal Seal save even
more money by recycling 80% of its water. In addition, it has enabled
Metal Seal to meet the discharge limits proposed by the new MP&M
rule. With this foundation, Metal Seal hopes to become a small
quantity hazardous waste generator. Presently, Metal Seal separates
its wastes into two streams, chrome (from the sodium dichromate
and red dye) and nonchrome. It loses the 20% of water to the chromium
wastes, because that water is not recycled. Treating all of the
waste as one stream used to generate 8-10 tons of F006 and F019
filter cake every 90 days, making Metal Seal a large quantity generator.
"Now we are down to a one-cubic-yard box, roughly 1,000 lbs
every 3-4 weeks. We are right on the edge of becoming a small quantity
generator," said Mr. Diemer. "When we add a sludge dryer
to take 50% of the moisture out of the filter cake, we should be
able to reduce hazardous waste (filter cake) below the 2,200 lb/month
cut off."
|
TABLE
II-Waste Disposal Cost Savings
|
|
Roll-Off Rental
Transportation (4x/year) Liners (4x/year)
Disposal/Treatment (each trip)
YEARLY TOTAL:
Hazmat Box (12x/year)
Transportation (6x/year)
Disposal/Treatment (12x/year)
YEARLY TOTAL:
|
Previous
Costs
$238.50/month
$300.00
$30.00
$175.00/ton
$11,182.50
Current Costs
$70.00
$400.00
$150.00/box
$5040.00
|
After separating
the chrome and nonchrome streams, rinse water from the zinc plating,
anodizing and passivating lines flows by gravity to two lift stations.
Air diaphragm pumps, controlled by level sensors in the lift stations,
pump the rinse water to the water recycling system feed tank. From
the feed tank, duplex feed pumps pressurize the water through backwashing
media filters, granular activated carbon filtration, cation ion
exchange and anion ion exchange. The deionized (DI) water is collected
in a storage tank where duplex pumps return it to the rinse tanks.
The return pumps also recirculate water through an ultraviolet light
to control microbiological growth in the stored water. The system
is capable of processing 100 gpm.
The backwashing
filtration system has two 36-inch diameter tanks of filter media.
The filter media removes solids that may precipitate when acid and
caustic rinse water combine in the system feed tank. During normal
operation, one tank processes the entire flow while the other is
in backwash or standby. Flow to the ion exchange system stops during
a filter backwash. A differential pressure switch senses the pressure
drop across the operating filter, initiating a filter backwash.
The filters can also backwash based on volume of water processed.
After passing
through the media filter, the water flows through two 42-inch diameter
granular activated carbon filters. The activated carbon removes
oils and dissolved organic compounds that could foul the ion exchange
resins. The carbon filters backwash automatically based on the water
volume processed. During filtration, both carbon tanks process solution.
During backwash, the full flow is processed through one tank, and
the filtered water is used to backwash the other tank. After the
activated carbon filter, bag filters are used to catch any solids
that pass through the backwashing filters.
After the water
has been processed through all the filtration steps, it goes through
duplex cation and duplex anion exchange tanks. The tanks are duplex
to provide an uninterrupted flow of DI water. DI water is collected
in a 4,000 gal tank, allowing for an uninterrupted supply to the
plating lines, even during operations such as filter backwashing,
where the flow rate temporarily slows down.
The main control
panel for the system contains the PLC that monitors and controls
all system functions. The PLC and all system controls are accessed
through an operator interface panel. The control panel also contains
a modem with a dedicated phone line, so that the PLC can be accessed
remotely for monitoring and troubleshooting.
As for the
operator, the display at his control is a touch screen that can
be used to adjust system set points (password protected) and display
and log system alarms. The display shows piping, tanks, vessels
and automatic valves. "This entire system is very easy to operate,"
stated Mr. Diemer. "We simply come in each morning, push a
button on the DI unit and open 7 valves, and we are ready for the
day." Flow and system status changes are shown by color changes.
Actual flow rates, conductivities and other parameters are displayed
as well.
All of these
changes have helped Metal Seal produce a better product more efficiently.
And, not only that, the system has helped the company save on chemical,
water and hazardous waste disposal costs. "We were averaging
about $7,000 a quarter on water bills before installing the system.
Our average bill now is $4,100. That's a 30% savings, even though
production has increased. We are spending 25 to 35% less on chemicals
and recycling 80% of our water. We have also achieved QS 9000 certification.
When we get to small quantity generator status, and we will achieve
that, we will be far ahead of the game," stated Mr. Diemer.
