Download Cleaner Production – Recovery of Tank Wash Water – Paint Factory

Cleaner Production – Recovery of Tank Wash Water –
Paint Factory
Background
The Paint Factory was established in 1972 as a family company in the outer suburbs of
Melbourne, for the manufacture of high performance architectural paints. Since then it has
developed a comprehensive product range, including all popular architectural paint types and
finishes. Its core range of products are high performance interior and exterior paints primers
and undercoats, stains and clear finishes. Since 1994 the Paint Factory’s production facility
has been located in Bayswater North where paints are manufactured for distribution across
Australia and Asia.
The Process
Paints are manufactured in batch blending tanks according to specific recipes. The Paint
Factory Production facility in Bayswater North can be separated into two distinct areas.
Water Based Acrylic
Solvent Based
1. Water Based Acrylic
The water based acrylic area has two
blending tanks where specific acrylic paint
recipes are produced. The general ingredients
for these types of paints are water, pigment,
resin,
additives
and
biocides
(anti
fungal/bacterial agents).
The pigment is
added to the blending tank in a powder form.
To prevent pigment dust emanating
throughout the factory, vacuum extraction
units are used.
Any residual pigment
dispersing out of the blending tank is drawn
up into the extraction unit, which then passes
through a number of filters. The filtered
residual powder is collected as solid waste.
Figure 1: Acrylic Blending Tanks
After a batch of paint was produced the blending tank and all associated tools used with that
batch (eg. agitator) need to be cleaned. Before the cleaner production initiatives the blending
tanks were cleaned by a low-pressure water rinse technique. All wastewater was then stored
in a 25,000L underground sludge-holding tank. Once every two months a waste disposal
company would empty the sludge tank at a cost of approximately $5,000.
2. Solvent
Solvent-based paints contain essentially the same core ingredients as acrylic paints besides the
distinction in base. Solvent-based paints are not susceptible to fungi and bacteria therefore no
biocide is required. The blending tank cleaning process is done with a solvent, which is
recycled back into the next batch as a raw material.
Cleaner Production
The
cleaner
production
initiative
implemented by the Paint Factory involved
the reuse of the wash water that was
previously being disposed of in the acrylic
area. An 800L holding tank was purchased
into which all white wash water was emptied
after cleaning.
White paint washing’s currently constitutes
over 60% of wastewater produced during
cleaning operations. The other 40% comes in
the form of green wash water. These green
washings are currently discharged into the
sludge tank, as they are unable to be
recycled back into the process.
Figure 2: Wash Water Holding Tank
The inability to recycle green wash water is due to its strong pigment and its potential
frequency of use. Opportunities to recycle this wash water are not frequent enough and are
limited to few product batches. To maintain the wash waters integrity large amounts of
biocide would be used, rendering recycling economically unviable.
As well as the wash water from the blending tanks, all
equipment used in the batching process is cleaned in a
dedicated trough. Wastewater from the trough is
temporarily stored in a bin with an automated mercury
pump system in place to transfer the trough water to the
holding tank.
The holding tank is treated and tested three times a week
with biocide to ensure the complete integrity of the wash
water. The wash water is then recycled into a
acrylic paint product batch.
Stringent research, development and quality control
testing has enabled the Paint Factory to develop
empirical alterations to product recipes to take into
account the use of waste water which has levels of
thickeners remaining in it. Hence raw materials, as
well as water, are being recycled. This additional
amount of thickener in each batch has also led to
enhanced product quality saving over $12,000 per annum.
Figure 3: The final product
In addition to the recycling of wash water, the purchase of a Karcher high-pressure water gun
has meant a reduction of cleaning time and wash water usage. This resulted in a cleaning
water usage reduction of 60% per batch or 70L of water per batch.
Paint
Blending
Vessel
Raw Materials
Paint
Washings
Recycled Wash Water
Biocide Addition
Wash Water
Holding Tank
Note: Adjustment in
recipy to allow for
addition of wash water
as raw material
Advantages of the Process
The main advantage has been the elimination of the major source of wastewater and the
associated cost savings. The high-pressure system has also decreased the time required for
cleaning.
Cost Benefit
Capital Costs
Tank
Pump
Bin
Piping
Stands
Karcher Gun
$1,000
$220
$12
$200
$100
$498
$2,030
Labour Costs
Plumber
Electrician
Fork Lift
Management
R&D Costs
TOTAL SET UPCOSTS
OPERATING COSTS
Biocide Usage, p/a
Savings
Waste Disposal, p/a
Labour, p/a
Water, p/a
Raw Material, p/a
TOTAL SAVINGS, p/a
PAYBACK PERIOD
$350
$125
$60
$100
$635
$3,250
$5,915
$1,121.12
$12,500
$3,900
$650
$12,272
$28,200.88
3 Months
Cleaner Production Incentives
There were a number of incentives for the Paint Factory to address its wastewater problem:
The company was going through a tough period and cost cutting measures needed to be
implemented.
Improved efficiency of process
Environmental Compliance
Improved Public Image
Barriers
The only barriers that were encountered were the research and development required in order
to understand the wastewater chemistry. There was no resistance from management towards
implementation since the capital outlay was minimal and the pay back period was incredibly
small.
Future Improvements
Use the two discarded resin tanks at the back of the plant to store liquid resin. Bulk resin
deliveries instead of 1000L OPTI tanks.
Future R&D to determine whether the green wastewater can be recycled.
Implementation of an Environmental Management System(EMS)
Contact Details
Fred Dellisola
Technical Operations Manager
No. 1 14-20 Kelvin Rd
Bayswater North
VIC, 3153
: 9761 5931 or 0411340 487
Fax: 9761 4681