There is one area of paper industry microbiology where active measures are needed to cultivate microbial flora: biological waste water treatment plants.
When focusing on activated sludge of aeration basin (anaerobic treatments will be discussed in another post), the roles of different microbes should first be understood.
The tasks of bacteria and protozoa - which are the beneficial microbial groups in the purification process - are different: bacteries are responsible for the transformations (mineralisation) of incoming organic compounds, Protozoa collects small particles (also bacteria) and acts as indicators of the activated sludge condition.
Bacteria shall also build up "flocs" which can settle down and be either returned backwards into the beginning of the purification process or totally removed from the plant. Significant amounts of nutrients will also be lead to the "sludge route" which is especially important for environmental reasons: no matter relatively low concentrations of nitrogen and phosphorus (compared with municipal waste water effluents), the volumes of P&P waste water effluents are huge.
Traditional parameters which are related to the microbiological status of activated sludge are C:P:R ratio, temperature, pH and oxygen concentration. In addition, the share of Protozoan indicator organisms are checked by microscopical methods.
ATP Assay is also a fast and reliable method to check the viability of activated sludge and control unfavourable sludge escape from secondary sedimentation basins (IM has written his second graduate work about this issue on 90's).
Incubations with PMEU equipment (FINNOFLAG Oy, Finland) have been very successful when the effects of low oxygen concentrations on the structure of flocs are the subject of the study. This method, in connection of bright field/dark field/phase contrast microscopy, gives also fast responses (even in hours) when the detrimental effects of toxic water fractions on activated sludge flora shall be checked.
There are many reasons for the bulking of activated sludge: nutrient supply, oxygen concentration, temperature etc. In all cases, a layer of activated sludge will rise on the surface of the basin and cannot be taken away from the water flow to sedimentation stages.
Measurements of redox potentials can give more information about the risks of anaerobic growth in biological waste water purification systems than sole oxygen concentration analyses(practical reslusts by IM). RO potential control may also work as a replacement/addition to traditional Respiratory Rate test, often used to check the viability of activated sludge.
Microbial activities continue also in sedimentation basins. IM has detected a significant rise of nitrogen concentration in certain basins in studies performed on 80's. The reason is obviously the activity of a coliform species, Klebsiella pneumoniae, which is able to fix nitrogen from atmosphere (nitrogen fixation). The routes of the pathogenic Legionella pneumophila in the purification process should also be investigated more deeply. Novel types of analytical methods to replace the traditional colony count methods (intended in the control of household water) shall be developed, however: L.pneumophila is very hard to "find" among other bacteria and fungi which are capable to grow extensively on selective nutrient media for Legionella.
ON LINE control has - until now - not got any role in HACCP of waste water treatment systems but promising technical solutions are already available for semi-continuous control of activated sludge microbiology.
Friday, July 18, 2008
Thursday, July 17, 2008
Biofuels from pulp industry have a gret potential in future.
IM follows frequently the network site "The Paper Index Times" which has published this new post today:
"Monday, July 14, 2008
Paper and Pulp Mills Poised to Produce Biofuels
No other industry is so well suited to produce fuels from waste wood cellulose than the paper/pulp industry. By converting pulp by-products from waste to precious fuel, pulp mills can do a big favour to themselves, the environment, and the energy consuming public.
The pulp and paper industry has the scale to produce more than 9 billion gallons per year of biofuels, or as much as 20,000 MW of biomass power - as much as 16 Quads of cumulative fossil energy savings – realize net CO2 emissions reductions of more than 100 million tons annually, in the process generating financial returns, relative to continued investment in existing technology, with internal rates of return between 15-40% depending of fuel prices and incentives, according to a presentation given by Navigant Consulting’s Ryan Katofsky at the “Florida Farm to Fuel Summit,” which took place in St. Petersburg July last year....Gasifying rather than incinerating black liquor in soda furnaces – as is common practice - results in the production of a number of by-products, including synthesis gas. The bio-syngas can then be turned into a range of liquid fuels, such as methanol, dimethyl ester (DME), Fischer-Tropsch synthetic diesel and hydrogen gas. _SourcePulp mills could easily become energy self-sufficient by using the waste process heat of paper manufacture, and eventually supply energy to the outside in the form of electricity or fuels. The more productive uses that can be found for solid waste, waste sludge, waste exhaust gases, waste heat, and waste water, the cleaner the environment will become--land, air, and water.
Labels: cellulosic fuels, garbage energy
"Monday, July 14, 2008
Paper and Pulp Mills Poised to Produce Biofuels
No other industry is so well suited to produce fuels from waste wood cellulose than the paper/pulp industry. By converting pulp by-products from waste to precious fuel, pulp mills can do a big favour to themselves, the environment, and the energy consuming public.
The pulp and paper industry has the scale to produce more than 9 billion gallons per year of biofuels, or as much as 20,000 MW of biomass power - as much as 16 Quads of cumulative fossil energy savings – realize net CO2 emissions reductions of more than 100 million tons annually, in the process generating financial returns, relative to continued investment in existing technology, with internal rates of return between 15-40% depending of fuel prices and incentives, according to a presentation given by Navigant Consulting’s Ryan Katofsky at the “Florida Farm to Fuel Summit,” which took place in St. Petersburg July last year....Gasifying rather than incinerating black liquor in soda furnaces – as is common practice - results in the production of a number of by-products, including synthesis gas. The bio-syngas can then be turned into a range of liquid fuels, such as methanol, dimethyl ester (DME), Fischer-Tropsch synthetic diesel and hydrogen gas. _SourcePulp mills could easily become energy self-sufficient by using the waste process heat of paper manufacture, and eventually supply energy to the outside in the form of electricity or fuels. The more productive uses that can be found for solid waste, waste sludge, waste exhaust gases, waste heat, and waste water, the cleaner the environment will become--land, air, and water.
Labels: cellulosic fuels, garbage energy
Saturday, July 12, 2008
Features of sporeforming bacteria.
Sporeformers are certain bacteria which can transform themselves from vegetative (= growing) form to spores (= resting form). Best-known examples of these bacteria are aerobic sporeformers ("bacillus-type", inc. Bacillus sp. , Paenibacillus sp. and other Gram-positive, aerobic sporeformers) and anaerobic sporeformers (most common species belong to the genus Clostridium). These bacteria are very common in all environments, especially in soils.
Spores of bacteria are not intended in the reproduction of organisms (like fungal spores) but to keep bacteria alive in conditions where they cannot be metabolically active. Sporulation is caused by the lack of nutrients, and germination of spores takes place whenever environmental conditions turn better for the growth of the bacterial cells.
These bacteria are a problem for paper industry because their spores tolerate dryness, cleaning agents and biocides very well. Their main sources are mineral pigments and starches, especially when these raw materials are delivered to the mills as dry powders. Whenever they are slurried, an effective biocide program shall be applied in the total system of their storage and dosing into the machines.
Another problems are analytical ones. Spores can be detected after a simple pasteurization of the samples (vegetative cells get killed, only spores stay alive) but this procedure kills also vegetative sporeformes. An analysis called "Sporeforming bacteria" does therefore not show potential sporeformers which are in vegetative growth phase. In addition, germination of spores, like every other chances in the properties of bacteria, takes certain time. This slows the growth of spores on nutrient media significantly. Fastest germination times can be achieved by PMEU incubator but the outgrowth of spores into vegetative cells may take much longer periods on the agar plates.
Evaluation of biocides should also be done with equipments like PMEU which show the different effects of biocides in the original samples.
Last but not least: if the growth of certain aerobic sporeformers has been very active, starch-degrading enzymes can stay active after biocidic treatments. Amylases can be found even after heat treatments because many of them are thermotolerant ones.
Sporeforming bacteria of paper industry have been studied very actively in Helsinki University, Dep. of Applied Chemistry and Microbiology. IM recommends to read scientific articles, written by the research group of Professor Mirja Salkinoja-Salonen, in magazines like "Applied and Environmental Microbiology" and "Industrial Microbiology and Biotechnology".
This group of bacteria is always a target of HACCP activities of paper mills, especially when products with high hygiene quality are manufactured. Studies to understand their features is therefore continuing also in future.
Spores of bacteria are not intended in the reproduction of organisms (like fungal spores) but to keep bacteria alive in conditions where they cannot be metabolically active. Sporulation is caused by the lack of nutrients, and germination of spores takes place whenever environmental conditions turn better for the growth of the bacterial cells.
These bacteria are a problem for paper industry because their spores tolerate dryness, cleaning agents and biocides very well. Their main sources are mineral pigments and starches, especially when these raw materials are delivered to the mills as dry powders. Whenever they are slurried, an effective biocide program shall be applied in the total system of their storage and dosing into the machines.
Another problems are analytical ones. Spores can be detected after a simple pasteurization of the samples (vegetative cells get killed, only spores stay alive) but this procedure kills also vegetative sporeformes. An analysis called "Sporeforming bacteria" does therefore not show potential sporeformers which are in vegetative growth phase. In addition, germination of spores, like every other chances in the properties of bacteria, takes certain time. This slows the growth of spores on nutrient media significantly. Fastest germination times can be achieved by PMEU incubator but the outgrowth of spores into vegetative cells may take much longer periods on the agar plates.
Evaluation of biocides should also be done with equipments like PMEU which show the different effects of biocides in the original samples.
Last but not least: if the growth of certain aerobic sporeformers has been very active, starch-degrading enzymes can stay active after biocidic treatments. Amylases can be found even after heat treatments because many of them are thermotolerant ones.
Sporeforming bacteria of paper industry have been studied very actively in Helsinki University, Dep. of Applied Chemistry and Microbiology. IM recommends to read scientific articles, written by the research group of Professor Mirja Salkinoja-Salonen, in magazines like "Applied and Environmental Microbiology" and "Industrial Microbiology and Biotechnology".
This group of bacteria is always a target of HACCP activities of paper mills, especially when products with high hygiene quality are manufactured. Studies to understand their features is therefore continuing also in future.
Monday, July 7, 2008
Concepts of microbial ecology and biotechnology in process industry.
Coming back to the issues of microbial ecology and biotechnology:
Both of them have helped IM to understand the multitude of microbial activities which are typical for paper industry. Technical framework, beginning from the preparation of raw materials and ending to the waste water treatment plants can be regarded as fermentors or bioreactors where growth conditions vary a lot. Everlasting input of bacteria (and sometimes also fungal organisms) contain strains which can be adapted into these processes and live in them over very long periods - even tens of years. These topics, definitely, belong also to the research area of microbial ecology and its theories about adaptation, competition, synergisms...
These issues have been discussed by IM already in previous posts and shall be taken into account - in more detailled form - in near future.
By the way - what would be more interesting than to have shared net forum of paper industry engineers, environmental microbiologists, ecologists, biotechnicians and other specialists to discuss about similarities and analogies between natural environments and paper mills? Even limnology gives hints to understand certain microbial activities - like the growth of microbes in water flows as biofilm organisms. Another analogy can be found when observing the microbial populations of lake or ocean sediments and the microbial flora of different kind of depositions in paper mill machinery.
IM is looking forward to hear various multiscience views by biologists, biotechnical and environmental microbiologists, ecologists, limnologists and oceanologists about similarities between natural environments and paper machines!
Both of them have helped IM to understand the multitude of microbial activities which are typical for paper industry. Technical framework, beginning from the preparation of raw materials and ending to the waste water treatment plants can be regarded as fermentors or bioreactors where growth conditions vary a lot. Everlasting input of bacteria (and sometimes also fungal organisms) contain strains which can be adapted into these processes and live in them over very long periods - even tens of years. These topics, definitely, belong also to the research area of microbial ecology and its theories about adaptation, competition, synergisms...
These issues have been discussed by IM already in previous posts and shall be taken into account - in more detailled form - in near future.
By the way - what would be more interesting than to have shared net forum of paper industry engineers, environmental microbiologists, ecologists, biotechnicians and other specialists to discuss about similarities and analogies between natural environments and paper mills? Even limnology gives hints to understand certain microbial activities - like the growth of microbes in water flows as biofilm organisms. Another analogy can be found when observing the microbial populations of lake or ocean sediments and the microbial flora of different kind of depositions in paper mill machinery.
IM is looking forward to hear various multiscience views by biologists, biotechnical and environmental microbiologists, ecologists, limnologists and oceanologists about similarities between natural environments and paper machines!
Sunday, July 6, 2008
Why shall paper industry be moved to foreign countries from Finland?
IM was sitting with an old friend from Helsinki on the terrace of his summer cottage (no water lines, no electricity)on yesterday evening.
- (IM) Where are we going in near future?
- Basic production (agriculture, fishing etc.) will be respected after a while...
- Why we cannot continue P&P production in Finland?
- Labour costs are not the problem. Their share is under 10% of the costs of paper production.
- But..?
- Transport of the products and price of the raw material are the main problems.
IM has read from local newspaper "KESKISUOMALAINEN" about the problems of timber production. A manager of timber enterprise told that "the taxes are the problem. Price of the Finnish raw wood is too high today. Government should help to have wood with acceptable prices..".
This is economy.
- (IM) Where are we going in near future?
- Basic production (agriculture, fishing etc.) will be respected after a while...
- Why we cannot continue P&P production in Finland?
- Labour costs are not the problem. Their share is under 10% of the costs of paper production.
- But..?
- Transport of the products and price of the raw material are the main problems.
IM has read from local newspaper "KESKISUOMALAINEN" about the problems of timber production. A manager of timber enterprise told that "the taxes are the problem. Price of the Finnish raw wood is too high today. Government should help to have wood with acceptable prices..".
This is economy.
Microbiology shall be taken as an important issue in paper production.
IM will thank Dr. Elias Hakalehto about his valuable comments!
It seems that there is only one industrial environment where the intense growth of harmful bacteria is allowed: paper and board production.
This is caused by the need of huge amounts of water inside paper mills. This water is carrying valuable raw materials and (despite the frequent questions by IM) the most spoiled water fractions will not be delivered to waste water treatment. The spare of water has led to (microbiologically) insane solutions like the use of certain white water fractions in spray water system of wire section. Every microbiologist knows what happens...
There are several microbiological threats in paper industry:
* spoilage of raw materials
* biofilm and slime problems of the machines
* defects of product hygiene
* health risks
Production of paper without water was discussed at 80's. It does not work. Connection of fibres in wire section has failed. Water is needed to form a network of fibres, strong enough to "jump" to pressing section. It is an impressive event: still having tens of percents water, paper will go independently over a gap between wire and pressing rolls, without any support...
Water is needed in paper machines, no doubt. But how to control its microbiological quality?
Harmful bacteria can (which IM has experienced) be detected with rapid methods like PMEU, ATP Assay and PCR. It is the question of (economical) resources if it will be done.
It seems that there is only one industrial environment where the intense growth of harmful bacteria is allowed: paper and board production.
This is caused by the need of huge amounts of water inside paper mills. This water is carrying valuable raw materials and (despite the frequent questions by IM) the most spoiled water fractions will not be delivered to waste water treatment. The spare of water has led to (microbiologically) insane solutions like the use of certain white water fractions in spray water system of wire section. Every microbiologist knows what happens...
There are several microbiological threats in paper industry:
* spoilage of raw materials
* biofilm and slime problems of the machines
* defects of product hygiene
* health risks
Production of paper without water was discussed at 80's. It does not work. Connection of fibres in wire section has failed. Water is needed to form a network of fibres, strong enough to "jump" to pressing section. It is an impressive event: still having tens of percents water, paper will go independently over a gap between wire and pressing rolls, without any support...
Water is needed in paper machines, no doubt. But how to control its microbiological quality?
Harmful bacteria can (which IM has experienced) be detected with rapid methods like PMEU, ATP Assay and PCR. It is the question of (economical) resources if it will be done.
Thursday, July 3, 2008
The role of Klebsiella pneumoniae as an opportunistic pathogen in paper industry.
Klebsiella pneumoniae is a common bacterium of the BERGEY's group "Gram-negative facultatively anaerobic rods", having motility by peritrichous flagella and being unable to perform oxidase test positively.
The former description indicates that we can set K.pneumoniae into the family Enterobacteriaceae with such, maybe better-known bacteria like Escherichia coli and Salmonella sp. They all have one distinct feature: they can grow either aerobically (= in an atmosphere containing oxygen) or anaerobically (= in an atmosphere without oxygen). The presence of two different energy metabolism, aerobic respiration and fermentation, allow this adaptation into two significantly different environments.
Klebsiella pneumoniae likes to live in wet environments and can use different sugars as the source of energy and carbon.
All these features of this bacterium declare its tendency to live in paper industry waters containing sugars from wood (waters originating mechanical pulp production; debarker waters; waste waters containing pulp mill effluents). The capability to use atmospheric nitrogen (N2) as the source of nitrogen (called nitrogen fixation) is also common among K.pneumoniae strains and gives to it good chances to compete with such microbes which are depending on organic nitrogen supply - which is often very poor in paper industry waters, having low N:C ratio.
What makes this peaceful situation more hazardous, are some other features of Klebsiella pneumoniae: its ability to produce exopolysaccharide capsel (= slime) and its resistance against several antibiotics. Optimal temperature for its growth is 35-37 oC which is responding to the body temperature of a man.
It has been described as an independent species already in 1885. Genus is named respecting famous Dr. Klebs, well-known microbiologist; name of this species comes from its ability to cause bacterial pneumoniae and other severe infections which may be fatal for weak persons (very young, very old or those having poor immune response like cancer patients). BROCK says: " ..the presence of bacteria in the blood is generally indicative of systemic infection. The most common pathogens found in blood include...enteric bacteria, especially Escherichia coli and Klebsiella pneumoniae...".
The physiological and biochemical features of K.pneumoniae strains isolated from patient samples and either from waste waters (DUFOUR & CABELLI 1976) or from paper industry processes (MENTU 1982) are very identical and the risk to be infected by this opportunistic pathogen is therefore obvious.
Finnish Work Environment Fund funded a research project in the beginning of 80's to investigate health risks, connected to the contaminated aerosols in the paper machine and debarker halls. K.pneumoniae was one of the microbes investigated in this research. The results of this extended project were published in Appl. Environ.Microbiology (SEPPO I. NIEMELÄ, PENTTI VÄÄTÄNEN, JUHA MENTU, ANTTI JOKINEN, PAAVO JÄPPINEN & PAAVO SILLANPÄÄ 1985). The writers said at the end of this article's Discussion: "...The lack of correlation between microbial incidence and occurrence of symptoms seems to indicate that permanent colonization of the process water microbes is not common or that the human pathogenity of these microbes is low. The microbes found in nasal cavities were evidently mostly transient. We conclude that the natural host defenses of the basically healthy adult worker population are normally effective enough to protect the workers from the the opportunistic pathogens present in the process waters and in the air of the paper mill environment. This does not preclude the possibility of a worker's becoming a host to a pathogenic microbe when the worker is in a subnormal state of health".
After 20 year from the publishing of this article, first cases of Legionella pneumophila infections, connected with paper industry, were found.
- Detailed list of references is not included in this article (to spare rows) but available on request from IM.
The former description indicates that we can set K.pneumoniae into the family Enterobacteriaceae with such, maybe better-known bacteria like Escherichia coli and Salmonella sp. They all have one distinct feature: they can grow either aerobically (= in an atmosphere containing oxygen) or anaerobically (= in an atmosphere without oxygen). The presence of two different energy metabolism, aerobic respiration and fermentation, allow this adaptation into two significantly different environments.
Klebsiella pneumoniae likes to live in wet environments and can use different sugars as the source of energy and carbon.
All these features of this bacterium declare its tendency to live in paper industry waters containing sugars from wood (waters originating mechanical pulp production; debarker waters; waste waters containing pulp mill effluents). The capability to use atmospheric nitrogen (N2) as the source of nitrogen (called nitrogen fixation) is also common among K.pneumoniae strains and gives to it good chances to compete with such microbes which are depending on organic nitrogen supply - which is often very poor in paper industry waters, having low N:C ratio.
What makes this peaceful situation more hazardous, are some other features of Klebsiella pneumoniae: its ability to produce exopolysaccharide capsel (= slime) and its resistance against several antibiotics. Optimal temperature for its growth is 35-37 oC which is responding to the body temperature of a man.
It has been described as an independent species already in 1885. Genus is named respecting famous Dr. Klebs, well-known microbiologist; name of this species comes from its ability to cause bacterial pneumoniae and other severe infections which may be fatal for weak persons (very young, very old or those having poor immune response like cancer patients). BROCK says: " ..the presence of bacteria in the blood is generally indicative of systemic infection. The most common pathogens found in blood include...enteric bacteria, especially Escherichia coli and Klebsiella pneumoniae...".
The physiological and biochemical features of K.pneumoniae strains isolated from patient samples and either from waste waters (DUFOUR & CABELLI 1976) or from paper industry processes (MENTU 1982) are very identical and the risk to be infected by this opportunistic pathogen is therefore obvious.
Finnish Work Environment Fund funded a research project in the beginning of 80's to investigate health risks, connected to the contaminated aerosols in the paper machine and debarker halls. K.pneumoniae was one of the microbes investigated in this research. The results of this extended project were published in Appl. Environ.Microbiology (SEPPO I. NIEMELÄ, PENTTI VÄÄTÄNEN, JUHA MENTU, ANTTI JOKINEN, PAAVO JÄPPINEN & PAAVO SILLANPÄÄ 1985). The writers said at the end of this article's Discussion: "...The lack of correlation between microbial incidence and occurrence of symptoms seems to indicate that permanent colonization of the process water microbes is not common or that the human pathogenity of these microbes is low. The microbes found in nasal cavities were evidently mostly transient. We conclude that the natural host defenses of the basically healthy adult worker population are normally effective enough to protect the workers from the the opportunistic pathogens present in the process waters and in the air of the paper mill environment. This does not preclude the possibility of a worker's becoming a host to a pathogenic microbe when the worker is in a subnormal state of health".
After 20 year from the publishing of this article, first cases of Legionella pneumophila infections, connected with paper industry, were found.
- Detailed list of references is not included in this article (to spare rows) but available on request from IM.
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