www.amazon-papyrus.comDELIVERING VALUE THROUGH PEOPLE CHEMISTRY
Controlling Microbiological Growth
and Foul Odors in Papermaking
Ezwar Roezzaman
Papermaking Process is Bioreactor
AspergillusMucorPenicillium
Protozoa
Algae
Aerobes
Facultative aerobesBacteria
AcinetobacterBacillus (spore-former)Pseudomonas
Single-cell:
BeggiatoaHaliscomenobacterSphaerotilus
Filamentous:
EnterobacterEscherichia coliKlebsiella
Clostridia Desulfovibrio Spirilla
Anaerobes
Filamentous or single-cell:
Paramecium
Coliforms:
(spore-former)
(sulfate-reducer)
Oscillatoria, Chlorella
Yeast
Mold
Fungi
Nutrients
PH
Retention
time
Oxygen
Levels
Temperature
Water
Slime Outbreaks
Higher Water Closure in Papermaking
Faster
accumulation of
solids & additives
Increased water
temperature
Higher System
Conductivity
Higher solid &
Microorganisms
contamination
load in effluent
• Lower oxygen
solubility in water
• Accelerate anaerobic
growth
Speedup corrosion
process
• Reintroduction of
microorganisms & odorous
agents to wetend
• Massive deposit problem
• Filamentous bacteria
bulking
• Difficulties in controlling
system retention
• Faster deposition
• Feeds Microorganisms
Anaerobic Bacteria Outbreaks
Anaerobic Bacteria
Reduced Fiber
strength
Bad smell
Toxic Gases
Explosion
Microbial Induced
Corrosion
Spoilage of Coating & Additives
Reduced brightness
Case Study : FW Consumption vs VFA in
recycled packaging mill
Negative correlation between FW consumption and VFA buildup in wetend.
Higher FW consumption reduces VFA
Common Microbiological Odors : H2S
and VFA
H2S• At 0.1 ppm - can be detected by the
human nose
• At 3 ppm - the odor becomes
objectionable
• At 10 ppm- Noticeable health affects
and headaches will occur
• At 100 ppm - people lose ability to
smell
• By 300 ppm - life threatening
• At 1000 ppm- irreversible
respiratory failure
• VFA• Fatty acids with a carbon chain of six
or fewer
• Intermediate chemistry of anaerobic
degradation into methanes
• Mainly acetic, butyric, propionic,
valeric acids
• VFA has different smell threshold
and characteristics
• Very common in recycled packaging
grades
• VFA may be generated in process or
come with reused water from WWTP
Degradation of organics
Sulfate reduction -230 mV
SO4
H2S HS- S2-
-250 to – 400 mv
VFA :
-100 to
-200 mV
Controlling microbiological related Odor
Mechanical / Design
Improvements
• Reduce generation of anaerobic conditions: improved agitation, Cascading ww, Chest aeration, reduce stagnant zone
• Use of Odor control equipments:
• Scrubbers
• Adsorbers
• UV, Plasma,
• etc.
Operational Improvements
• Proper chest level management
• Proper Housekeepings
Chemical Improvements
• Biocides
• Cleaners
• Air phase treatment
• Enzymes
• Living bacteria culture
• Oxidizers
• Alkaline soln.
• Metal precipitants
• etc.
Improving Biocide Program
• Change from “deposit control” focus to overall aspect
of Microbiological control
• Proper system survey and product selection
Some biocide actives are not effective in anaerobic
conditions
• Proper program design, application, and monitoring
Include monitoring of anaerobic bacteria
• Periodic program review and optimization
Minimizing Odor in WWTP
• Strict monitoring & control on WWTP operational
parameters on each process stage – continuous review
& optimize if necessary
• Preventing anaerobic conditions in aerobic stages
• Minimizing retention under anaerobic conditions
• Reduction on input of sulfates and control nutrients
• Periodic cleaning / maintenance of the WWTP system
• Addition of odor control chemicals
Advantages of Chemical Treatments
• Generally high removal efficiency
• Lower cost than mechanical systems – reduce big
capital investment
• Flexibility of treatment options based on type of chemistry,
system requirements, and regulatory compliances
• Little equipment maintenance and operation cost
• Ability to match chemical specific odor problems
• High ROI : savings on raw materials / chemical additives,
operational & cleaning costs
Paper Machine Dryer Exhaust
odor
Exhaust in dryer
Direct addition of Odor Neutralizer
Cooling Tower & vacuum Sealing
water treatment
Cool air in
few odor out
Warm water
Contain H2S
OC 3803/
OC 3801 spray nozzles
• Cooling Tower
OC 3808
/ OC 3818
OC 3808
H2S Control in Effluent Plant
H2S odor
H2S odor
Different Spray Application Method
Mist fan
Spray in exhaust / chimney
Sludge processing plant
Waste water tank
Brightness Improvement
• The pulp comes out from storage
tower turns black in color after
long shut down
• H2S generated by SRB reacts with
metals and create blackish metal
sulfide. Brightness of Pulp and the
finish paper was reduced. Foul
H2S odor also found
• Addition of AmiSense OC 3820
helps to recover the pulp & finish
paper brightness at shirt period of
time
Monitoring Equipment
• The monitoring Program is
tailored designed according to
program needs
• Biocide monitoring should include
anaerobic counts, ORP
• Measurement of total sulfides,
VFA
• Measurement of odorous gases Sulfide Test
Acetic Acid gas tester
H2S gas tester
Ammonia gas tester
Mercaptan gas tester
VOC tester
Summary
• Papermaking process is favorable environment for growth of
microorganisms, and may results is several microbiological related
• Microbiological related-odor problems in papermaking is an
increasing trend, especially with higher use of recycled fibers and
higher water closure
• Better control of microbiological related odors can be approached
through mechanical, operational, and chemical improvements
• Having and effective biocide program and odor control application
are important to produce paper process and products low in odor.